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Diffstat (limited to 'modules/libpref/Preferences.cpp')
| -rw-r--r-- | modules/libpref/Preferences.cpp | 5519 |
1 files changed, 5519 insertions, 0 deletions
diff --git a/modules/libpref/Preferences.cpp b/modules/libpref/Preferences.cpp new file mode 100644 index 0000000000..cfc498d5c2 --- /dev/null +++ b/modules/libpref/Preferences.cpp @@ -0,0 +1,5519 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +// Documentation for libpref is in modules/libpref/docs/index.rst. + +#include <ctype.h> +#include <stdlib.h> +#include <string.h> + +#include "SharedPrefMap.h" + +#include "base/basictypes.h" +#include "GeckoProfiler.h" +#include "MainThreadUtils.h" +#include "mozilla/ArenaAllocatorExtensions.h" +#include "mozilla/ArenaAllocator.h" +#include "mozilla/ArrayUtils.h" +#include "mozilla/Attributes.h" +#include "mozilla/Components.h" +#include "mozilla/dom/PContent.h" +#include "mozilla/HashFunctions.h" +#include "mozilla/HashTable.h" +#include "mozilla/Logging.h" +#include "mozilla/Maybe.h" +#include "mozilla/MemoryReporting.h" +#include "mozilla/Omnijar.h" +#include "mozilla/Preferences.h" +#include "mozilla/ResultExtensions.h" +#include "mozilla/SchedulerGroup.h" +#include "mozilla/ScopeExit.h" +#include "mozilla/Services.h" +#include "mozilla/ServoStyleSet.h" +#include "mozilla/SpinEventLoopUntil.h" +#include "mozilla/StaticMutex.h" +#include "mozilla/StaticPrefsAll.h" +#include "mozilla/SyncRunnable.h" +#include "mozilla/Telemetry.h" +#include "mozilla/UniquePtrExtensions.h" +#include "mozilla/URLPreloader.h" +#include "mozilla/Variant.h" +#include "mozilla/Vector.h" +#include "nsAppDirectoryServiceDefs.h" +#include "nsCategoryManagerUtils.h" +#include "nsClassHashtable.h" +#include "nsCOMArray.h" +#include "nsCOMPtr.h" +#include "nsComponentManagerUtils.h" +#include "nsCRT.h" +#include "nsDataHashtable.h" +#include "nsDirectoryServiceDefs.h" +#include "nsIConsoleService.h" +#include "nsIFile.h" +#include "nsIMemoryReporter.h" +#include "nsIObserver.h" +#include "nsIObserverService.h" +#include "nsIOutputStream.h" +#include "nsIPrefBranch.h" +#include "nsIPrefLocalizedString.h" +#include "nsIRelativeFilePref.h" +#include "nsISafeOutputStream.h" +#include "nsISimpleEnumerator.h" +#include "nsIStringBundle.h" +#include "nsISupportsImpl.h" +#include "nsISupportsPrimitives.h" +#include "nsIZipReader.h" +#include "nsNetUtil.h" +#include "nsPrintfCString.h" +#include "nsQuickSort.h" +#include "nsReadableUtils.h" +#include "nsRefPtrHashtable.h" +#include "nsRelativeFilePref.h" +#include "nsString.h" +#include "nsTArray.h" +#include "nsThreadUtils.h" +#include "nsUTF8Utils.h" +#include "nsWeakReference.h" +#include "nsXPCOMCID.h" +#include "nsXPCOM.h" +#include "nsXULAppAPI.h" +#include "nsZipArchive.h" +#include "plbase64.h" +#include "PLDHashTable.h" +#include "plstr.h" +#include "prlink.h" +#include "xpcpublic.h" + +#ifdef DEBUG +# include <map> +#endif + +#ifdef MOZ_MEMORY +# include "mozmemory.h" +#endif + +#ifdef XP_WIN +# include "windows.h" +#endif + +using namespace mozilla; + +using ipc::FileDescriptor; + +#ifdef DEBUG + +# define ENSURE_PARENT_PROCESS(func, pref) \ + do { \ + if (MOZ_UNLIKELY(!XRE_IsParentProcess())) { \ + nsPrintfCString msg( \ + "ENSURE_PARENT_PROCESS: called %s on %s in a non-parent process", \ + func, pref); \ + NS_ERROR(msg.get()); \ + return NS_ERROR_NOT_AVAILABLE; \ + } \ + } while (0) + +#else // DEBUG + +# define ENSURE_PARENT_PROCESS(func, pref) \ + if (MOZ_UNLIKELY(!XRE_IsParentProcess())) { \ + return NS_ERROR_NOT_AVAILABLE; \ + } + +#endif // DEBUG + +//=========================================================================== +// Low-level types and operations +//=========================================================================== + +typedef nsTArray<nsCString> PrefSaveData; + +// 1 MB should be enough for everyone. +static const uint32_t MAX_PREF_LENGTH = 1 * 1024 * 1024; +// Actually, 4kb should be enough for everyone. +static const uint32_t MAX_ADVISABLE_PREF_LENGTH = 4 * 1024; + +// This is used for pref names and string pref values. We encode the string +// length, then a '/', then the string chars. This encoding means there are no +// special chars that are forbidden or require escaping. +static void SerializeAndAppendString(const nsCString& aChars, nsCString& aStr) { + aStr.AppendInt(aChars.Length()); + aStr.Append('/'); + aStr.Append(aChars); +} + +static char* DeserializeString(char* aChars, nsCString& aStr) { + char* p = aChars; + uint32_t length = strtol(p, &p, 10); + MOZ_ASSERT(p[0] == '/'); + p++; // move past the '/' + aStr.Assign(p, length); + p += length; // move past the string itself + return p; +} + +// Keep this in sync with PrefValue in parser/src/lib.rs. +union PrefValue { + // PrefValues within Pref objects own their chars. PrefValues passed around + // as arguments don't own their chars. + const char* mStringVal; + int32_t mIntVal; + bool mBoolVal; + + PrefValue() = default; + + explicit PrefValue(bool aVal) : mBoolVal(aVal) {} + + explicit PrefValue(int32_t aVal) : mIntVal(aVal) {} + + explicit PrefValue(const char* aVal) : mStringVal(aVal) {} + + bool Equals(PrefType aType, PrefValue aValue) { + switch (aType) { + case PrefType::String: { + if (mStringVal && aValue.mStringVal) { + return strcmp(mStringVal, aValue.mStringVal) == 0; + } + if (!mStringVal && !aValue.mStringVal) { + return true; + } + return false; + } + + case PrefType::Int: + return mIntVal == aValue.mIntVal; + + case PrefType::Bool: + return mBoolVal == aValue.mBoolVal; + + default: + MOZ_CRASH("Unhandled enum value"); + } + } + + template <typename T> + T Get() const; + + void Init(PrefType aNewType, PrefValue aNewValue) { + if (aNewType == PrefType::String) { + MOZ_ASSERT(aNewValue.mStringVal); + aNewValue.mStringVal = moz_xstrdup(aNewValue.mStringVal); + } + *this = aNewValue; + } + + void Clear(PrefType aType) { + if (aType == PrefType::String) { + free(const_cast<char*>(mStringVal)); + } + + // Zero the entire value (regardless of type) via mStringVal. + mStringVal = nullptr; + } + + void Replace(bool aHasValue, PrefType aOldType, PrefType aNewType, + PrefValue aNewValue) { + if (aHasValue) { + Clear(aOldType); + } + Init(aNewType, aNewValue); + } + + void ToDomPrefValue(PrefType aType, dom::PrefValue* aDomValue) { + switch (aType) { + case PrefType::String: + *aDomValue = nsDependentCString(mStringVal); + return; + + case PrefType::Int: + *aDomValue = mIntVal; + return; + + case PrefType::Bool: + *aDomValue = mBoolVal; + return; + + default: + MOZ_CRASH(); + } + } + + PrefType FromDomPrefValue(const dom::PrefValue& aDomValue) { + switch (aDomValue.type()) { + case dom::PrefValue::TnsCString: + mStringVal = aDomValue.get_nsCString().get(); + return PrefType::String; + + case dom::PrefValue::Tint32_t: + mIntVal = aDomValue.get_int32_t(); + return PrefType::Int; + + case dom::PrefValue::Tbool: + mBoolVal = aDomValue.get_bool(); + return PrefType::Bool; + + default: + MOZ_CRASH(); + } + } + + void SerializeAndAppend(PrefType aType, nsCString& aStr) { + switch (aType) { + case PrefType::Bool: + aStr.Append(mBoolVal ? 'T' : 'F'); + break; + + case PrefType::Int: + aStr.AppendInt(mIntVal); + break; + + case PrefType::String: { + SerializeAndAppendString(nsDependentCString(mStringVal), aStr); + break; + } + + case PrefType::None: + default: + MOZ_CRASH(); + } + } + + static char* Deserialize(PrefType aType, char* aStr, + Maybe<dom::PrefValue>* aDomValue) { + char* p = aStr; + + switch (aType) { + case PrefType::Bool: + if (*p == 'T') { + *aDomValue = Some(true); + } else if (*p == 'F') { + *aDomValue = Some(false); + } else { + *aDomValue = Some(false); + NS_ERROR("bad bool pref value"); + } + p++; + return p; + + case PrefType::Int: { + *aDomValue = Some(int32_t(strtol(p, &p, 10))); + return p; + } + + case PrefType::String: { + nsCString str; + p = DeserializeString(p, str); + *aDomValue = Some(str); + return p; + } + + default: + MOZ_CRASH(); + } + } +}; + +template <> +bool PrefValue::Get() const { + return mBoolVal; +} + +template <> +int32_t PrefValue::Get() const { + return mIntVal; +} + +template <> +nsDependentCString PrefValue::Get() const { + return nsDependentCString(mStringVal); +} + +#ifdef DEBUG +const char* PrefTypeToString(PrefType aType) { + switch (aType) { + case PrefType::None: + return "none"; + case PrefType::String: + return "string"; + case PrefType::Int: + return "int"; + case PrefType::Bool: + return "bool"; + default: + MOZ_CRASH("Unhandled enum value"); + } +} +#endif + +// Assign to aResult a quoted, escaped copy of aOriginal. +static void StrEscape(const char* aOriginal, nsCString& aResult) { + if (aOriginal == nullptr) { + aResult.AssignLiteral("\"\""); + return; + } + + // JavaScript does not allow quotes, slashes, or line terminators inside + // strings so we must escape them. ECMAScript defines four line terminators, + // but we're only worrying about \r and \n here. We currently feed our pref + // script to the JS interpreter as Latin-1 so we won't encounter \u2028 + // (line separator) or \u2029 (paragraph separator). + // + // WARNING: There are hints that we may be moving to storing prefs as utf8. + // If we ever feed them to the JS compiler as UTF8 then we'll have to worry + // about the multibyte sequences that would be interpreted as \u2028 and + // \u2029. + const char* p; + + aResult.Assign('"'); + + // Paranoid worst case all slashes will free quickly. + for (p = aOriginal; *p; ++p) { + switch (*p) { + case '\n': + aResult.AppendLiteral("\\n"); + break; + + case '\r': + aResult.AppendLiteral("\\r"); + break; + + case '\\': + aResult.AppendLiteral("\\\\"); + break; + + case '\"': + aResult.AppendLiteral("\\\""); + break; + + default: + aResult.Append(*p); + break; + } + } + + aResult.Append('"'); +} + +namespace mozilla { +struct PrefsSizes { + PrefsSizes() + : mHashTable(0), + mPrefValues(0), + mStringValues(0), + mRootBranches(0), + mPrefNameArena(0), + mCallbacksObjects(0), + mCallbacksDomains(0), + mMisc(0) {} + + size_t mHashTable; + size_t mPrefValues; + size_t mStringValues; + size_t mRootBranches; + size_t mPrefNameArena; + size_t mCallbacksObjects; + size_t mCallbacksDomains; + size_t mMisc; +}; +} // namespace mozilla + +static StaticRefPtr<SharedPrefMap> gSharedMap; + +// Arena for Pref names. Inside a function so we can assert it's only accessed +// on the main thread. +static inline ArenaAllocator<4096, 1>& PrefNameArena() { + MOZ_ASSERT(NS_IsMainThread()); + + static ArenaAllocator<4096, 1> sPrefNameArena; + return sPrefNameArena; +} + +class PrefWrapper; + +class Pref { + public: + explicit Pref(const nsACString& aName) + : mName(ArenaStrdup(aName, PrefNameArena()), aName.Length()), + mType(static_cast<uint32_t>(PrefType::None)), + mIsSticky(false), + mIsLocked(false), + mHasDefaultValue(false), + mHasUserValue(false), + mIsSkippedByIteration(false), + mDefaultValue(), + mUserValue() {} + + ~Pref() { + // There's no need to free mName because it's allocated in memory owned by + // sPrefNameArena. + + mDefaultValue.Clear(Type()); + mUserValue.Clear(Type()); + } + + const char* Name() const { return mName.get(); } + const nsDependentCString& NameString() const { return mName; } + + // Types. + + PrefType Type() const { return static_cast<PrefType>(mType); } + void SetType(PrefType aType) { mType = static_cast<uint32_t>(aType); } + + bool IsType(PrefType aType) const { return Type() == aType; } + bool IsTypeNone() const { return IsType(PrefType::None); } + bool IsTypeString() const { return IsType(PrefType::String); } + bool IsTypeInt() const { return IsType(PrefType::Int); } + bool IsTypeBool() const { return IsType(PrefType::Bool); } + + // Other properties. + + bool IsLocked() const { return mIsLocked; } + void SetIsLocked(bool aValue) { mIsLocked = aValue; } + bool IsSkippedByIteration() const { return mIsSkippedByIteration; } + void SetIsSkippedByIteration(bool aValue) { mIsSkippedByIteration = aValue; } + + bool IsSticky() const { return mIsSticky; } + + bool HasDefaultValue() const { return mHasDefaultValue; } + bool HasUserValue() const { return mHasUserValue; } + + template <typename T> + void AddToMap(SharedPrefMapBuilder& aMap) { + aMap.Add(NameString(), + {HasDefaultValue(), HasUserValue(), IsSticky(), IsLocked(), + IsSkippedByIteration()}, + HasDefaultValue() ? mDefaultValue.Get<T>() : T(), + HasUserValue() ? mUserValue.Get<T>() : T()); + } + + void AddToMap(SharedPrefMapBuilder& aMap) { + if (IsTypeBool()) { + AddToMap<bool>(aMap); + } else if (IsTypeInt()) { + AddToMap<int32_t>(aMap); + } else if (IsTypeString()) { + AddToMap<nsDependentCString>(aMap); + } else { + MOZ_ASSERT_UNREACHABLE("Unexpected preference type"); + } + } + + // Other operations. + + bool GetBoolValue(PrefValueKind aKind = PrefValueKind::User) const { + MOZ_ASSERT(IsTypeBool()); + MOZ_ASSERT(aKind == PrefValueKind::Default ? HasDefaultValue() + : HasUserValue()); + + return aKind == PrefValueKind::Default ? mDefaultValue.mBoolVal + : mUserValue.mBoolVal; + } + + int32_t GetIntValue(PrefValueKind aKind = PrefValueKind::User) const { + MOZ_ASSERT(IsTypeInt()); + MOZ_ASSERT(aKind == PrefValueKind::Default ? HasDefaultValue() + : HasUserValue()); + + return aKind == PrefValueKind::Default ? mDefaultValue.mIntVal + : mUserValue.mIntVal; + } + + const char* GetBareStringValue( + PrefValueKind aKind = PrefValueKind::User) const { + MOZ_ASSERT(IsTypeString()); + MOZ_ASSERT(aKind == PrefValueKind::Default ? HasDefaultValue() + : HasUserValue()); + + return aKind == PrefValueKind::Default ? mDefaultValue.mStringVal + : mUserValue.mStringVal; + } + + nsDependentCString GetStringValue( + PrefValueKind aKind = PrefValueKind::User) const { + return nsDependentCString(GetBareStringValue(aKind)); + } + + void ToDomPref(dom::Pref* aDomPref) { + MOZ_ASSERT(XRE_IsParentProcess()); + + aDomPref->name() = mName; + + aDomPref->isLocked() = mIsLocked; + + if (mHasDefaultValue) { + aDomPref->defaultValue() = Some(dom::PrefValue()); + mDefaultValue.ToDomPrefValue(Type(), &aDomPref->defaultValue().ref()); + } else { + aDomPref->defaultValue() = Nothing(); + } + + if (mHasUserValue) { + aDomPref->userValue() = Some(dom::PrefValue()); + mUserValue.ToDomPrefValue(Type(), &aDomPref->userValue().ref()); + } else { + aDomPref->userValue() = Nothing(); + } + + MOZ_ASSERT(aDomPref->defaultValue().isNothing() || + aDomPref->userValue().isNothing() || + (aDomPref->defaultValue().ref().type() == + aDomPref->userValue().ref().type())); + } + + void FromDomPref(const dom::Pref& aDomPref, bool* aValueChanged) { + MOZ_ASSERT(!XRE_IsParentProcess()); + MOZ_ASSERT(mName == aDomPref.name()); + + mIsLocked = aDomPref.isLocked(); + + const Maybe<dom::PrefValue>& defaultValue = aDomPref.defaultValue(); + bool defaultValueChanged = false; + if (defaultValue.isSome()) { + PrefValue value; + PrefType type = value.FromDomPrefValue(defaultValue.ref()); + if (!ValueMatches(PrefValueKind::Default, type, value)) { + // Type() is PrefType::None if it's a newly added pref. This is ok. + mDefaultValue.Replace(mHasDefaultValue, Type(), type, value); + SetType(type); + mHasDefaultValue = true; + defaultValueChanged = true; + } + } + // Note: we never clear a default value. + + const Maybe<dom::PrefValue>& userValue = aDomPref.userValue(); + bool userValueChanged = false; + if (userValue.isSome()) { + PrefValue value; + PrefType type = value.FromDomPrefValue(userValue.ref()); + if (!ValueMatches(PrefValueKind::User, type, value)) { + // Type() is PrefType::None if it's a newly added pref. This is ok. + mUserValue.Replace(mHasUserValue, Type(), type, value); + SetType(type); + mHasUserValue = true; + userValueChanged = true; + } + } else if (mHasUserValue) { + ClearUserValue(); + userValueChanged = true; + } + + if (userValueChanged || (defaultValueChanged && !mHasUserValue)) { + *aValueChanged = true; + } + } + + void FromWrapper(PrefWrapper& aWrapper); + + bool HasAdvisablySizedValues() { + MOZ_ASSERT(XRE_IsParentProcess()); + + if (!IsTypeString()) { + return true; + } + + if (mHasDefaultValue && + strlen(mDefaultValue.mStringVal) > MAX_ADVISABLE_PREF_LENGTH) { + return false; + } + + if (mHasUserValue && + strlen(mUserValue.mStringVal) > MAX_ADVISABLE_PREF_LENGTH) { + return false; + } + + return true; + } + + private: + bool ValueMatches(PrefValueKind aKind, PrefType aType, PrefValue aValue) { + return IsType(aType) && + (aKind == PrefValueKind::Default + ? mHasDefaultValue && mDefaultValue.Equals(aType, aValue) + : mHasUserValue && mUserValue.Equals(aType, aValue)); + } + + public: + void ClearUserValue() { + mUserValue.Clear(Type()); + mHasUserValue = false; + } + + nsresult SetDefaultValue(PrefType aType, PrefValue aValue, bool aIsSticky, + bool aIsLocked, bool* aValueChanged) { + // Types must always match when setting the default value. + if (!IsType(aType)) { + return NS_ERROR_UNEXPECTED; + } + + // Should we set the default value? Only if the pref is not locked, and + // doing so would change the default value. + if (!IsLocked()) { + if (aIsLocked) { + SetIsLocked(true); + } + if (!ValueMatches(PrefValueKind::Default, aType, aValue)) { + mDefaultValue.Replace(mHasDefaultValue, Type(), aType, aValue); + mHasDefaultValue = true; + if (aIsSticky) { + mIsSticky = true; + } + if (!mHasUserValue) { + *aValueChanged = true; + } + // What if we change the default to be the same as the user value? + // Should we clear the user value? Currently we don't. + } + } + return NS_OK; + } + + nsresult SetUserValue(PrefType aType, PrefValue aValue, bool aFromInit, + bool* aValueChanged) { + // If we have a default value, types must match when setting the user + // value. + if (mHasDefaultValue && !IsType(aType)) { + return NS_ERROR_UNEXPECTED; + } + + // Should we clear the user value, if present? Only if the new user value + // matches the default value, and the pref isn't sticky, and we aren't + // force-setting it during initialization. + if (ValueMatches(PrefValueKind::Default, aType, aValue) && !mIsSticky && + !aFromInit) { + if (mHasUserValue) { + ClearUserValue(); + if (!IsLocked()) { + *aValueChanged = true; + } + } + + // Otherwise, should we set the user value? Only if doing so would + // change the user value. + } else if (!ValueMatches(PrefValueKind::User, aType, aValue)) { + mUserValue.Replace(mHasUserValue, Type(), aType, aValue); + SetType(aType); // needed because we may have changed the type + mHasUserValue = true; + if (!IsLocked()) { + *aValueChanged = true; + } + } + return NS_OK; + } + + // Prefs are serialized in a manner that mirrors dom::Pref. The two should be + // kept in sync. E.g. if something is added to one it should also be added to + // the other. (It would be nice to be able to use the code generated from + // IPDL for serializing dom::Pref here instead of writing by hand this + // serialization/deserialization. Unfortunately, that generated code is + // difficult to use directly, outside of the IPDL IPC code.) + // + // The grammar for the serialized prefs has the following form. + // + // <pref> = <type> <locked> ':' <name> ':' <value>? ':' <value>? '\n' + // <type> = 'B' | 'I' | 'S' + // <locked> = 'L' | '-' + // <name> = <string-value> + // <value> = <bool-value> | <int-value> | <string-value> + // <bool-value> = 'T' | 'F' + // <int-value> = an integer literal accepted by strtol() + // <string-value> = <int-value> '/' <chars> + // <chars> = any char sequence of length dictated by the preceding + // <int-value>. + // + // No whitespace is tolerated between tokens. <type> must match the types of + // the values. + // + // The serialization is text-based, rather than binary, for the following + // reasons. + // + // - The size difference wouldn't be much different between text-based and + // binary. Most of the space is for strings (pref names and string pref + // values), which would be the same in both styles. And other differences + // would be minimal, e.g. small integers are shorter in text but long + // integers are longer in text. + // + // - Likewise, speed differences should be negligible. + // + // - It's much easier to debug a text-based serialization. E.g. you can + // print it and inspect it easily in a debugger. + // + // Examples of unlocked boolean prefs: + // - "B-:8/my.bool1:F:T\n" + // - "B-:8/my.bool2:F:\n" + // - "B-:8/my.bool3::T\n" + // + // Examples of locked integer prefs: + // - "IL:7/my.int1:0:1\n" + // - "IL:7/my.int2:123:\n" + // - "IL:7/my.int3::-99\n" + // + // Examples of unlocked string prefs: + // - "S-:10/my.string1:3/abc:4/wxyz\n" + // - "S-:10/my.string2:5/1.234:\n" + // - "S-:10/my.string3::7/string!\n" + + void SerializeAndAppend(nsCString& aStr) { + switch (Type()) { + case PrefType::Bool: + aStr.Append('B'); + break; + + case PrefType::Int: + aStr.Append('I'); + break; + + case PrefType::String: { + aStr.Append('S'); + break; + } + + case PrefType::None: + default: + MOZ_CRASH(); + } + + aStr.Append(mIsLocked ? 'L' : '-'); + aStr.Append(':'); + + SerializeAndAppendString(mName, aStr); + aStr.Append(':'); + + if (mHasDefaultValue) { + mDefaultValue.SerializeAndAppend(Type(), aStr); + } + aStr.Append(':'); + + if (mHasUserValue) { + mUserValue.SerializeAndAppend(Type(), aStr); + } + aStr.Append('\n'); + } + + static char* Deserialize(char* aStr, dom::Pref* aDomPref) { + char* p = aStr; + + // The type. + PrefType type; + if (*p == 'B') { + type = PrefType::Bool; + } else if (*p == 'I') { + type = PrefType::Int; + } else if (*p == 'S') { + type = PrefType::String; + } else { + NS_ERROR("bad pref type"); + type = PrefType::None; + } + p++; // move past the type char + + // Locked? + bool isLocked; + if (*p == 'L') { + isLocked = true; + } else if (*p == '-') { + isLocked = false; + } else { + NS_ERROR("bad pref locked status"); + isLocked = false; + } + p++; // move past the isLocked char + + MOZ_ASSERT(*p == ':'); + p++; // move past the ':' + + // The pref name. + nsCString name; + p = DeserializeString(p, name); + + MOZ_ASSERT(*p == ':'); + p++; // move past the ':' preceding the default value + + Maybe<dom::PrefValue> maybeDefaultValue; + if (*p != ':') { + dom::PrefValue defaultValue; + p = PrefValue::Deserialize(type, p, &maybeDefaultValue); + } + + MOZ_ASSERT(*p == ':'); + p++; // move past the ':' between the default and user values + + Maybe<dom::PrefValue> maybeUserValue; + if (*p != '\n') { + dom::PrefValue userValue; + p = PrefValue::Deserialize(type, p, &maybeUserValue); + } + + MOZ_ASSERT(*p == '\n'); + p++; // move past the '\n' following the user value + + *aDomPref = dom::Pref(name, isLocked, maybeDefaultValue, maybeUserValue); + + return p; + } + + void AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf, PrefsSizes& aSizes) { + // Note: mName is allocated in sPrefNameArena, measured elsewhere. + aSizes.mPrefValues += aMallocSizeOf(this); + if (IsTypeString()) { + if (mHasDefaultValue) { + aSizes.mStringValues += aMallocSizeOf(mDefaultValue.mStringVal); + } + if (mHasUserValue) { + aSizes.mStringValues += aMallocSizeOf(mUserValue.mStringVal); + } + } + } + + private: + const nsDependentCString mName; // allocated in sPrefNameArena + + uint32_t mType : 2; + uint32_t mIsSticky : 1; + uint32_t mIsLocked : 1; + uint32_t mHasDefaultValue : 1; + uint32_t mHasUserValue : 1; + uint32_t mIsSkippedByIteration : 1; + + PrefValue mDefaultValue; + PrefValue mUserValue; +}; + +struct PrefHasher { + using Key = UniquePtr<Pref>; + using Lookup = const char*; + + static HashNumber hash(const Lookup aLookup) { return HashString(aLookup); } + + static bool match(const Key& aKey, const Lookup aLookup) { + if (!aLookup || !aKey->Name()) { + return false; + } + + return strcmp(aLookup, aKey->Name()) == 0; + } +}; + +using PrefWrapperBase = Variant<Pref*, SharedPrefMap::Pref>; +class MOZ_STACK_CLASS PrefWrapper : public PrefWrapperBase { + using SharedPref = const SharedPrefMap::Pref; + + public: + MOZ_IMPLICIT PrefWrapper(Pref* aPref) : PrefWrapperBase(AsVariant(aPref)) {} + + MOZ_IMPLICIT PrefWrapper(const SharedPrefMap::Pref& aPref) + : PrefWrapperBase(AsVariant(aPref)) {} + + // Types. + + bool IsType(PrefType aType) const { return Type() == aType; } + bool IsTypeNone() const { return IsType(PrefType::None); } + bool IsTypeString() const { return IsType(PrefType::String); } + bool IsTypeInt() const { return IsType(PrefType::Int); } + bool IsTypeBool() const { return IsType(PrefType::Bool); } + +#define FORWARD(retType, method) \ + retType method() const { \ + struct Matcher { \ + retType operator()(const Pref* aPref) { return aPref->method(); } \ + retType operator()(SharedPref& aPref) { return aPref.method(); } \ + }; \ + return match(Matcher()); \ + } + + FORWARD(bool, IsLocked) + FORWARD(bool, IsSticky) + FORWARD(bool, HasDefaultValue) + FORWARD(bool, HasUserValue) + FORWARD(const char*, Name) + FORWARD(nsCString, NameString) + FORWARD(PrefType, Type) +#undef FORWARD + +#define FORWARD(retType, method) \ + retType method(PrefValueKind aKind = PrefValueKind::User) const { \ + struct Matcher { \ + PrefValueKind mKind; \ + \ + retType operator()(const Pref* aPref) { return aPref->method(mKind); } \ + retType operator()(SharedPref& aPref) { return aPref.method(mKind); } \ + }; \ + return match(Matcher{aKind}); \ + } + + FORWARD(bool, GetBoolValue) + FORWARD(int32_t, GetIntValue) + FORWARD(nsCString, GetStringValue) + FORWARD(const char*, GetBareStringValue) +#undef FORWARD + + PrefValue GetValue(PrefValueKind aKind = PrefValueKind::User) const { + switch (Type()) { + case PrefType::Bool: + return PrefValue{GetBoolValue(aKind)}; + case PrefType::Int: + return PrefValue{GetIntValue(aKind)}; + case PrefType::String: + return PrefValue{GetBareStringValue(aKind)}; + default: + MOZ_ASSERT_UNREACHABLE("Unexpected pref type"); + return PrefValue{}; + } + } + + Result<PrefValueKind, nsresult> WantValueKind(PrefType aType, + PrefValueKind aKind) const { + if (Type() != aType) { + return Err(NS_ERROR_UNEXPECTED); + } + + if (aKind == PrefValueKind::Default || IsLocked() || !HasUserValue()) { + if (!HasDefaultValue()) { + return Err(NS_ERROR_UNEXPECTED); + } + return PrefValueKind::Default; + } + return PrefValueKind::User; + } + + nsresult GetValue(PrefValueKind aKind, bool* aResult) const { + PrefValueKind kind; + MOZ_TRY_VAR(kind, WantValueKind(PrefType::Bool, aKind)); + + *aResult = GetBoolValue(kind); + return NS_OK; + } + + nsresult GetValue(PrefValueKind aKind, int32_t* aResult) const { + PrefValueKind kind; + MOZ_TRY_VAR(kind, WantValueKind(PrefType::Int, aKind)); + + *aResult = GetIntValue(kind); + return NS_OK; + } + + nsresult GetValue(PrefValueKind aKind, uint32_t* aResult) const { + return GetValue(aKind, reinterpret_cast<int32_t*>(aResult)); + } + + nsresult GetValue(PrefValueKind aKind, float* aResult) const { + nsAutoCString result; + nsresult rv = GetValue(aKind, result); + if (NS_SUCCEEDED(rv)) { + // ToFloat() does a locale-independent conversion. + *aResult = result.ToFloat(&rv); + } + return rv; + } + + nsresult GetValue(PrefValueKind aKind, nsACString& aResult) const { + PrefValueKind kind; + MOZ_TRY_VAR(kind, WantValueKind(PrefType::String, aKind)); + + aResult = GetStringValue(kind); + return NS_OK; + } + + // Returns false if this pref doesn't have a user value worth saving. + bool UserValueToStringForSaving(nsCString& aStr) { + // Should we save the user value, if present? Only if it does not match the + // default value, or it is sticky. + if (HasUserValue() && + (!ValueMatches(PrefValueKind::Default, Type(), GetValue()) || + IsSticky())) { + if (IsTypeString()) { + StrEscape(GetStringValue().get(), aStr); + + } else if (IsTypeInt()) { + aStr.AppendInt(GetIntValue()); + + } else if (IsTypeBool()) { + aStr = GetBoolValue() ? "true" : "false"; + } + return true; + } + + // Do not save default prefs that haven't changed. + return false; + } + + bool Matches(PrefType aType, PrefValueKind aKind, PrefValue& aValue, + bool aIsSticky, bool aIsLocked) const { + return (ValueMatches(aKind, aType, aValue) && aIsSticky == IsSticky() && + aIsLocked == IsLocked()); + } + + bool ValueMatches(PrefValueKind aKind, PrefType aType, + const PrefValue& aValue) const { + if (!IsType(aType)) { + return false; + } + if (!(aKind == PrefValueKind::Default ? HasDefaultValue() + : HasUserValue())) { + return false; + } + switch (aType) { + case PrefType::Bool: + return GetBoolValue(aKind) == aValue.mBoolVal; + case PrefType::Int: + return GetIntValue(aKind) == aValue.mIntVal; + case PrefType::String: + return strcmp(GetBareStringValue(aKind), aValue.mStringVal) == 0; + default: + MOZ_ASSERT_UNREACHABLE("Unexpected preference type"); + return false; + } + } +}; + +void Pref::FromWrapper(PrefWrapper& aWrapper) { + MOZ_ASSERT(aWrapper.is<SharedPrefMap::Pref>()); + auto pref = aWrapper.as<SharedPrefMap::Pref>(); + + MOZ_ASSERT(IsTypeNone()); + MOZ_ASSERT(mName == pref.NameString()); + + mType = uint32_t(pref.Type()); + + mIsLocked = pref.IsLocked(); + mIsSticky = pref.IsSticky(); + + mHasDefaultValue = pref.HasDefaultValue(); + mHasUserValue = pref.HasUserValue(); + + if (mHasDefaultValue) { + mDefaultValue.Init(Type(), aWrapper.GetValue(PrefValueKind::Default)); + } + if (mHasUserValue) { + mUserValue.Init(Type(), aWrapper.GetValue(PrefValueKind::User)); + } +} + +class CallbackNode { + public: + CallbackNode(const nsACString& aDomain, PrefChangedFunc aFunc, void* aData, + Preferences::MatchKind aMatchKind) + : mDomain(AsVariant(nsCString(aDomain))), + mFunc(aFunc), + mData(aData), + mNextAndMatchKind(aMatchKind) {} + + CallbackNode(const char** aDomains, PrefChangedFunc aFunc, void* aData, + Preferences::MatchKind aMatchKind) + : mDomain(AsVariant(aDomains)), + mFunc(aFunc), + mData(aData), + mNextAndMatchKind(aMatchKind) {} + + // mDomain is a UniquePtr<>, so any uses of Domain() should only be temporary + // borrows. + const Variant<nsCString, const char**>& Domain() const { return mDomain; } + + PrefChangedFunc Func() const { return mFunc; } + void ClearFunc() { mFunc = nullptr; } + + void* Data() const { return mData; } + + Preferences::MatchKind MatchKind() const { + return static_cast<Preferences::MatchKind>(mNextAndMatchKind & + kMatchKindMask); + } + + bool DomainIs(const nsACString& aDomain) const { + return mDomain.is<nsCString>() && mDomain.as<nsCString>() == aDomain; + } + + bool DomainIs(const char** aPrefs) const { + return mDomain == AsVariant(aPrefs); + } + + bool Matches(const nsACString& aPrefName) const { + auto match = [&](const nsACString& aStr) { + return MatchKind() == Preferences::ExactMatch + ? aPrefName == aStr + : StringBeginsWith(aPrefName, aStr); + }; + + if (mDomain.is<nsCString>()) { + return match(mDomain.as<nsCString>()); + } + for (const char** ptr = mDomain.as<const char**>(); *ptr; ptr++) { + if (match(nsDependentCString(*ptr))) { + return true; + } + } + return false; + } + + CallbackNode* Next() const { + return reinterpret_cast<CallbackNode*>(mNextAndMatchKind & kNextMask); + } + + void SetNext(CallbackNode* aNext) { + uintptr_t matchKind = mNextAndMatchKind & kMatchKindMask; + mNextAndMatchKind = reinterpret_cast<uintptr_t>(aNext); + MOZ_ASSERT((mNextAndMatchKind & kMatchKindMask) == 0); + mNextAndMatchKind |= matchKind; + } + + void AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf, PrefsSizes& aSizes) { + aSizes.mCallbacksObjects += aMallocSizeOf(this); + if (mDomain.is<nsCString>()) { + aSizes.mCallbacksDomains += + mDomain.as<nsCString>().SizeOfExcludingThisIfUnshared(aMallocSizeOf); + } + } + + private: + static const uintptr_t kMatchKindMask = uintptr_t(0x1); + static const uintptr_t kNextMask = ~kMatchKindMask; + + Variant<nsCString, const char**> mDomain; + + // If someone attempts to remove the node from the callback list while + // NotifyCallbacks() is running, |func| is set to nullptr. Such nodes will + // be removed at the end of NotifyCallbacks(). + PrefChangedFunc mFunc; + void* mData; + + // Conceptually this is two fields: + // - CallbackNode* mNext; + // - Preferences::MatchKind mMatchKind; + // They are combined into a tagged pointer to save memory. + uintptr_t mNextAndMatchKind; +}; + +using PrefsHashTable = HashSet<UniquePtr<Pref>, PrefHasher>; + +// The main prefs hash table. Inside a function so we can assert it's only +// accessed on the main thread. (That assertion can be avoided but only do so +// with great care!) +static inline PrefsHashTable*& HashTable(bool aOffMainThread = false) { + MOZ_ASSERT(NS_IsMainThread() || ServoStyleSet::IsInServoTraversal()); + static PrefsHashTable* sHashTable = nullptr; + return sHashTable; +} + +#ifdef DEBUG +// This defines the type used to store our `once` mirrors checker. We can't use +// HashMap for now due to alignment restrictions when dealing with +// std::function<void()> (see bug 1557617). +typedef std::function<void()> AntiFootgunCallback; +struct CompareStr { + bool operator()(char const* a, char const* b) const { + return std::strcmp(a, b) < 0; + } +}; +typedef std::map<const char*, AntiFootgunCallback, CompareStr> AntiFootgunMap; +static AntiFootgunMap* gOnceStaticPrefsAntiFootgun; +#endif + +// The callback list contains all the priority callbacks followed by the +// non-priority callbacks. gLastPriorityNode records where the first part ends. +static CallbackNode* gFirstCallback = nullptr; +static CallbackNode* gLastPriorityNode = nullptr; + +#ifdef DEBUG +# define ACCESS_COUNTS +#endif + +#ifdef ACCESS_COUNTS +using AccessCountsHashTable = nsDataHashtable<nsCStringHashKey, uint32_t>; +static AccessCountsHashTable* gAccessCounts = nullptr; + +static void AddAccessCount(const nsACString& aPrefName) { + // FIXME: Servo reads preferences from background threads in unsafe ways (bug + // 1474789), and triggers assertions here if we try to add usage count entries + // from background threads. + if (NS_IsMainThread()) { + uint32_t& count = gAccessCounts->GetOrInsert(aPrefName); + count++; + } +} + +static void AddAccessCount(const char* aPrefName) { + AddAccessCount(nsDependentCString(aPrefName)); +} +#else +static void MOZ_MAYBE_UNUSED AddAccessCount(const nsACString& aPrefName) {} + +static void AddAccessCount(const char* aPrefName) {} +#endif + +// These are only used during the call to NotifyCallbacks(). +static bool gCallbacksInProgress = false; +static bool gShouldCleanupDeadNodes = false; + +class PrefsHashIter { + using Iterator = decltype(HashTable()->modIter()); + using ElemType = Pref*; + + Iterator mIter; + + public: + explicit PrefsHashIter(PrefsHashTable* aTable) : mIter(aTable->modIter()) {} + + class Elem { + friend class PrefsHashIter; + + PrefsHashIter& mParent; + bool mDone; + + Elem(PrefsHashIter& aIter, bool aDone) : mParent(aIter), mDone(aDone) {} + + Iterator& Iter() { return mParent.mIter; } + + public: + Elem& operator*() { return *this; } + + ElemType get() { + if (mDone) { + return nullptr; + } + return Iter().get().get(); + } + ElemType get() const { return const_cast<Elem*>(this)->get(); } + + ElemType operator->() { return get(); } + ElemType operator->() const { return get(); } + + operator ElemType() { return get(); } + + void Remove() { Iter().remove(); } + + Elem& operator++() { + MOZ_ASSERT(!mDone); + Iter().next(); + mDone = Iter().done(); + return *this; + } + + bool operator!=(Elem& other) { + return mDone != other.mDone || this->get() != other.get(); + } + }; + + Elem begin() { return Elem(*this, mIter.done()); } + + Elem end() { return Elem(*this, true); } +}; + +class PrefsIter { + using Iterator = decltype(HashTable()->iter()); + using ElemType = PrefWrapper; + + using HashElem = PrefsHashIter::Elem; + using SharedElem = SharedPrefMap::Pref; + + using ElemTypeVariant = Variant<HashElem, SharedElem>; + + SharedPrefMap* mSharedMap; + PrefsHashTable* mHashTable; + PrefsHashIter mIter; + + ElemTypeVariant mPos; + ElemTypeVariant mEnd; + + Maybe<PrefWrapper> mEntry; + + public: + PrefsIter(PrefsHashTable* aHashTable, SharedPrefMap* aSharedMap) + : mSharedMap(aSharedMap), + mHashTable(aHashTable), + mIter(aHashTable), + mPos(AsVariant(mIter.begin())), + mEnd(AsVariant(mIter.end())) { + if (Done()) { + NextIterator(); + } + } + + private: +#define MATCH(type, ...) \ + do { \ + struct Matcher { \ + PrefsIter& mIter; \ + type operator()(HashElem& pos) { \ + HashElem& end MOZ_MAYBE_UNUSED = mIter.mEnd.as<HashElem>(); \ + __VA_ARGS__; \ + } \ + type operator()(SharedElem& pos) { \ + SharedElem& end MOZ_MAYBE_UNUSED = mIter.mEnd.as<SharedElem>(); \ + __VA_ARGS__; \ + } \ + }; \ + return mPos.match(Matcher{*this}); \ + } while (0); + + bool Done() { MATCH(bool, return pos == end); } + + PrefWrapper MakeEntry() { MATCH(PrefWrapper, return PrefWrapper(pos)); } + + void NextEntry() { + mEntry.reset(); + MATCH(void, ++pos); + } +#undef MATCH + + bool Next() { + NextEntry(); + return !Done() || NextIterator(); + } + + bool NextIterator() { + if (mPos.is<HashElem>() && mSharedMap) { + mPos = AsVariant(mSharedMap->begin()); + mEnd = AsVariant(mSharedMap->end()); + return !Done(); + } + return false; + } + + bool IteratingBase() { return mPos.is<SharedElem>(); } + + PrefWrapper& Entry() { + MOZ_ASSERT(!Done()); + + if (!mEntry.isSome()) { + mEntry.emplace(MakeEntry()); + } + return mEntry.ref(); + } + + public: + class Elem { + friend class PrefsIter; + + PrefsIter& mParent; + bool mDone; + + Elem(PrefsIter& aIter, bool aDone) : mParent(aIter), mDone(aDone) { + SkipDuplicates(); + } + + void Next() { mDone = !mParent.Next(); } + + void SkipDuplicates() { + while (!mDone && + (mParent.IteratingBase() ? mParent.mHashTable->has(ref().Name()) + : ref().IsTypeNone())) { + Next(); + } + } + + public: + Elem& operator*() { return *this; } + + ElemType& ref() { return mParent.Entry(); } + const ElemType& ref() const { return const_cast<Elem*>(this)->ref(); } + + ElemType* operator->() { return &ref(); } + const ElemType* operator->() const { return &ref(); } + + operator ElemType() { return ref(); } + + Elem& operator++() { + MOZ_ASSERT(!mDone); + Next(); + SkipDuplicates(); + return *this; + } + + bool operator!=(Elem& other) { + if (mDone != other.mDone) { + return true; + } + if (mDone) { + return false; + } + return &this->ref() != &other.ref(); + } + }; + + Elem begin() { return {*this, Done()}; } + + Elem end() { return {*this, true}; } +}; + +static Pref* pref_HashTableLookup(const char* aPrefName); + +static void NotifyCallbacks(const nsCString& aPrefName, + const PrefWrapper* aPref = nullptr); + +static void NotifyCallbacks(const nsCString& aPrefName, + const PrefWrapper& aPref) { + NotifyCallbacks(aPrefName, &aPref); +} + +// The approximate number of preferences in the dynamic hashtable for the parent +// and content processes, respectively. These numbers are used to determine the +// initial size of the dynamic preference hashtables, and should be chosen to +// avoid rehashing during normal usage. The actual number of preferences will, +// or course, change over time, but these numbers only need to be within a +// binary order of magnitude of the actual values to remain effective. +// +// The number for the parent process should reflect the total number of +// preferences in the database, since the parent process needs to initially +// build a dynamic hashtable of the entire preference database. The number for +// the child process should reflect the number of preferences which are likely +// to change after the startup of the first content process, since content +// processes only store changed preferences on top of a snapshot of the database +// created at startup. +// +// Note: The capacity of a hashtable doubles when its length reaches an exact +// power of two. A table with an initial length of 64 is twice as large as one +// with an initial length of 63. This is important in content processes, where +// lookup speed is less critical and we pay the price of the additional overhead +// for each content process. So the initial content length should generally be +// *under* the next power-of-two larger than its expected length. +constexpr size_t kHashTableInitialLengthParent = 3000; +constexpr size_t kHashTableInitialLengthContent = 64; + +static PrefSaveData pref_savePrefs() { + MOZ_ASSERT(NS_IsMainThread()); + + PrefSaveData savedPrefs(HashTable()->count()); + + for (auto& pref : PrefsIter(HashTable(), gSharedMap)) { + nsAutoCString prefValueStr; + if (!pref->UserValueToStringForSaving(prefValueStr)) { + continue; + } + + nsAutoCString prefNameStr; + StrEscape(pref->Name(), prefNameStr); + + nsPrintfCString str("user_pref(%s, %s);", prefNameStr.get(), + prefValueStr.get()); + + savedPrefs.AppendElement(str); + } + + return savedPrefs; +} + +#ifdef DEBUG + +// Note that this never changes in the parent process, and is only read in +// content processes. +static bool gContentProcessPrefsAreInited = false; + +#endif // DEBUG + +static Pref* pref_HashTableLookup(const char* aPrefName) { + MOZ_ASSERT(NS_IsMainThread() || ServoStyleSet::IsInServoTraversal()); + + MOZ_ASSERT_IF(!XRE_IsParentProcess(), gContentProcessPrefsAreInited); + + // We use readonlyThreadsafeLookup() because we often have concurrent lookups + // from multiple Stylo threads. This is safe because those threads cannot + // modify sHashTable, and the main thread is blocked while Stylo threads are + // doing these lookups. + auto p = HashTable()->readonlyThreadsafeLookup(aPrefName); + return p ? p->get() : nullptr; +} + +// While notifying preference callbacks, this holds the wrapper for the +// preference being notified, in order to optimize lookups. +// +// Note: Callbacks and lookups only happen on the main thread, so this is safe +// to use without locking. +static const PrefWrapper* gCallbackPref; + +Maybe<PrefWrapper> pref_SharedLookup(const char* aPrefName) { + MOZ_DIAGNOSTIC_ASSERT(gSharedMap, "gSharedMap must be initialized"); + if (Maybe<SharedPrefMap::Pref> pref = gSharedMap->Get(aPrefName)) { + return Some(*pref); + } + return Nothing(); +} + +Maybe<PrefWrapper> pref_Lookup(const char* aPrefName, + bool aIncludeTypeNone = false) { + MOZ_ASSERT(NS_IsMainThread() || ServoStyleSet::IsInServoTraversal()); + + AddAccessCount(aPrefName); + + if (gCallbackPref && strcmp(aPrefName, gCallbackPref->Name()) == 0) { + return Some(*gCallbackPref); + } + if (Pref* pref = pref_HashTableLookup(aPrefName)) { + if (aIncludeTypeNone || !pref->IsTypeNone()) { + return Some(pref); + } + } else if (gSharedMap) { + return pref_SharedLookup(aPrefName); + } + + return Nothing(); +} + +static Result<Pref*, nsresult> pref_LookupForModify( + const nsCString& aPrefName, + const std::function<bool(const PrefWrapper&)>& aCheckFn) { + Maybe<PrefWrapper> wrapper = + pref_Lookup(aPrefName.get(), /* includeTypeNone */ true); + if (wrapper.isNothing()) { + return Err(NS_ERROR_INVALID_ARG); + } + if (!aCheckFn(*wrapper)) { + return nullptr; + } + if (wrapper->is<Pref*>()) { + return wrapper->as<Pref*>(); + } + + Pref* pref = new Pref(aPrefName); + if (!HashTable()->putNew(aPrefName.get(), pref)) { + delete pref; + return Err(NS_ERROR_OUT_OF_MEMORY); + } + pref->FromWrapper(*wrapper); + return pref; +} + +static nsresult pref_SetPref(const nsCString& aPrefName, PrefType aType, + PrefValueKind aKind, PrefValue aValue, + bool aIsSticky, bool aIsLocked, bool aFromInit) { + MOZ_ASSERT(XRE_IsParentProcess()); + MOZ_ASSERT(NS_IsMainThread()); + + if (!HashTable()) { + return NS_ERROR_OUT_OF_MEMORY; + } + + Pref* pref = nullptr; + if (gSharedMap) { + auto result = + pref_LookupForModify(aPrefName, [&](const PrefWrapper& aWrapper) { + return !aWrapper.Matches(aType, aKind, aValue, aIsSticky, aIsLocked); + }); + if (result.isOk() && !(pref = result.unwrap())) { + // No changes required. + return NS_OK; + } + } + + if (!pref) { + auto p = HashTable()->lookupForAdd(aPrefName.get()); + if (!p) { + pref = new Pref(aPrefName); + pref->SetType(aType); + if (!HashTable()->add(p, pref)) { + delete pref; + return NS_ERROR_OUT_OF_MEMORY; + } + } else { + pref = p->get(); + } + } + + bool valueChanged = false; + nsresult rv; + if (aKind == PrefValueKind::Default) { + rv = pref->SetDefaultValue(aType, aValue, aIsSticky, aIsLocked, + &valueChanged); + } else { + MOZ_ASSERT(!aIsLocked); // `locked` is disallowed in user pref files + rv = pref->SetUserValue(aType, aValue, aFromInit, &valueChanged); + } + if (NS_FAILED(rv)) { + NS_WARNING( + nsPrintfCString("Rejected attempt to change type of pref %s's %s value " + "from %s to %s", + aPrefName.get(), + (aKind == PrefValueKind::Default) ? "default" : "user", + PrefTypeToString(pref->Type()), PrefTypeToString(aType)) + .get()); + + return rv; + } + + if (valueChanged) { + if (aKind == PrefValueKind::User) { + Preferences::HandleDirty(); + } + NotifyCallbacks(aPrefName, PrefWrapper(pref)); + } + + return NS_OK; +} + +// Removes |node| from callback list. Returns the node after the deleted one. +static CallbackNode* pref_RemoveCallbackNode(CallbackNode* aNode, + CallbackNode* aPrevNode) { + MOZ_ASSERT(!aPrevNode || aPrevNode->Next() == aNode); + MOZ_ASSERT(aPrevNode || gFirstCallback == aNode); + MOZ_ASSERT(!gCallbacksInProgress); + + CallbackNode* next_node = aNode->Next(); + if (aPrevNode) { + aPrevNode->SetNext(next_node); + } else { + gFirstCallback = next_node; + } + if (gLastPriorityNode == aNode) { + gLastPriorityNode = aPrevNode; + } + delete aNode; + return next_node; +} + +static void NotifyCallbacks(const nsCString& aPrefName, + const PrefWrapper* aPref) { + bool reentered = gCallbacksInProgress; + + gCallbackPref = aPref; + auto cleanup = MakeScopeExit([]() { gCallbackPref = nullptr; }); + + // Nodes must not be deleted while gCallbacksInProgress is true. + // Nodes that need to be deleted are marked for deletion by nulling + // out the |func| pointer. We release them at the end of this function + // if we haven't reentered. + gCallbacksInProgress = true; + + for (CallbackNode* node = gFirstCallback; node; node = node->Next()) { + if (node->Func()) { + if (node->Matches(aPrefName)) { + (node->Func())(aPrefName.get(), node->Data()); + } + } + } + + gCallbacksInProgress = reentered; + + if (gShouldCleanupDeadNodes && !gCallbacksInProgress) { + CallbackNode* prev_node = nullptr; + CallbackNode* node = gFirstCallback; + + while (node) { + if (!node->Func()) { + node = pref_RemoveCallbackNode(node, prev_node); + } else { + prev_node = node; + node = node->Next(); + } + } + gShouldCleanupDeadNodes = false; + } + +#ifdef DEBUG + if (XRE_IsParentProcess() && + !StaticPrefs::preferences_force_disable_check_once_policy() && + (StaticPrefs::preferences_check_once_policy() || xpc::IsInAutomation())) { + // Check that we aren't modifying a `once`-mirrored pref using that pref + // name. We have about 100 `once`-mirrored prefs. std::map performs a + // search in O(log n), so this is fast enough. + MOZ_ASSERT(gOnceStaticPrefsAntiFootgun); + auto search = gOnceStaticPrefsAntiFootgun->find(aPrefName.get()); + if (search != gOnceStaticPrefsAntiFootgun->end()) { + // Run the callback. + (search->second)(); + } + } +#endif +} + +//=========================================================================== +// Prefs parsing +//=========================================================================== + +extern "C" { + +// Keep this in sync with PrefFn in parser/src/lib.rs. +typedef void (*PrefsParserPrefFn)(const char* aPrefName, PrefType aType, + PrefValueKind aKind, PrefValue aValue, + bool aIsSticky, bool aIsLocked); + +// Keep this in sync with ErrorFn in parser/src/lib.rs. +// +// `aMsg` is just a borrow of the string, and must be copied if it is used +// outside the lifetime of the prefs_parser_parse() call. +typedef void (*PrefsParserErrorFn)(const char* aMsg); + +// Keep this in sync with prefs_parser_parse() in parser/src/lib.rs. +bool prefs_parser_parse(const char* aPath, PrefValueKind aKind, + const char* aBuf, size_t aLen, + PrefsParserPrefFn aPrefFn, PrefsParserErrorFn aErrorFn); +} + +class Parser { + public: + Parser() = default; + ~Parser() = default; + + bool Parse(PrefValueKind aKind, const char* aPath, const nsCString& aBuf) { + MOZ_ASSERT(XRE_IsParentProcess()); + return prefs_parser_parse(aPath, aKind, aBuf.get(), aBuf.Length(), + HandlePref, HandleError); + } + + private: + static void HandlePref(const char* aPrefName, PrefType aType, + PrefValueKind aKind, PrefValue aValue, bool aIsSticky, + bool aIsLocked) { + MOZ_ASSERT(XRE_IsParentProcess()); + pref_SetPref(nsDependentCString(aPrefName), aType, aKind, aValue, aIsSticky, + aIsLocked, + /* fromInit */ true); + } + + static void HandleError(const char* aMsg) { + nsresult rv; + nsCOMPtr<nsIConsoleService> console = + do_GetService("@mozilla.org/consoleservice;1", &rv); + if (NS_SUCCEEDED(rv)) { + console->LogStringMessage(NS_ConvertUTF8toUTF16(aMsg).get()); + } +#ifdef DEBUG + NS_ERROR(aMsg); +#else + printf_stderr("%s\n", aMsg); +#endif + } +}; + +// The following code is test code for the gtest. + +static void TestParseErrorHandlePref(const char* aPrefName, PrefType aType, + PrefValueKind aKind, PrefValue aValue, + bool aIsSticky, bool aIsLocked) {} + +static nsCString gTestParseErrorMsgs; + +static void TestParseErrorHandleError(const char* aMsg) { + gTestParseErrorMsgs.Append(aMsg); + gTestParseErrorMsgs.Append('\n'); +} + +// Keep this in sync with the declaration in test/gtest/Parser.cpp. +void TestParseError(PrefValueKind aKind, const char* aText, + nsCString& aErrorMsg) { + prefs_parser_parse("test", aKind, aText, strlen(aText), + TestParseErrorHandlePref, TestParseErrorHandleError); + + // Copy the error messages into the outparam, then clear them from + // gTestParseErrorMsgs. + aErrorMsg.Assign(gTestParseErrorMsgs); + gTestParseErrorMsgs.Truncate(); +} + +//=========================================================================== +// nsPrefBranch et al. +//=========================================================================== + +namespace mozilla { +class PreferenceServiceReporter; +} // namespace mozilla + +class PrefCallback : public PLDHashEntryHdr { + friend class mozilla::PreferenceServiceReporter; + + public: + typedef PrefCallback* KeyType; + typedef const PrefCallback* KeyTypePointer; + + static const PrefCallback* KeyToPointer(PrefCallback* aKey) { return aKey; } + + static PLDHashNumber HashKey(const PrefCallback* aKey) { + uint32_t hash = HashString(aKey->mDomain); + return AddToHash(hash, aKey->mCanonical); + } + + public: + // Create a PrefCallback with a strong reference to its observer. + PrefCallback(const nsACString& aDomain, nsIObserver* aObserver, + nsPrefBranch* aBranch) + : mDomain(aDomain), + mBranch(aBranch), + mWeakRef(nullptr), + mStrongRef(aObserver) { + MOZ_COUNT_CTOR(PrefCallback); + nsCOMPtr<nsISupports> canonical = do_QueryInterface(aObserver); + mCanonical = canonical; + } + + // Create a PrefCallback with a weak reference to its observer. + PrefCallback(const nsACString& aDomain, nsISupportsWeakReference* aObserver, + nsPrefBranch* aBranch) + : mDomain(aDomain), + mBranch(aBranch), + mWeakRef(do_GetWeakReference(aObserver)), + mStrongRef(nullptr) { + MOZ_COUNT_CTOR(PrefCallback); + nsCOMPtr<nsISupports> canonical = do_QueryInterface(aObserver); + mCanonical = canonical; + } + + // This is explicitly not a copy constructor. + explicit PrefCallback(const PrefCallback*& aCopy) + : mDomain(aCopy->mDomain), + mBranch(aCopy->mBranch), + mWeakRef(aCopy->mWeakRef), + mStrongRef(aCopy->mStrongRef), + mCanonical(aCopy->mCanonical) { + MOZ_COUNT_CTOR(PrefCallback); + } + + PrefCallback(const PrefCallback&) = delete; + PrefCallback(PrefCallback&&) = default; + + MOZ_COUNTED_DTOR(PrefCallback) + + bool KeyEquals(const PrefCallback* aKey) const { + // We want to be able to look up a weakly-referencing PrefCallback after + // its observer has died so we can remove it from the table. Once the + // callback's observer dies, its canonical pointer is stale -- in + // particular, we may have allocated a new observer in the same spot in + // memory! So we can't just compare canonical pointers to determine whether + // aKey refers to the same observer as this. + // + // Our workaround is based on the way we use this hashtable: When we ask + // the hashtable to remove a PrefCallback whose weak reference has expired, + // we use as the key for removal the same object as was inserted into the + // hashtable. Thus we can say that if one of the keys' weak references has + // expired, the two keys are equal iff they're the same object. + + if (IsExpired() || aKey->IsExpired()) { + return this == aKey; + } + + if (mCanonical != aKey->mCanonical) { + return false; + } + + return mDomain.Equals(aKey->mDomain); + } + + PrefCallback* GetKey() const { return const_cast<PrefCallback*>(this); } + + // Get a reference to the callback's observer, or null if the observer was + // weakly referenced and has been destroyed. + already_AddRefed<nsIObserver> GetObserver() const { + if (!IsWeak()) { + nsCOMPtr<nsIObserver> copy = mStrongRef; + return copy.forget(); + } + + nsCOMPtr<nsIObserver> observer = do_QueryReferent(mWeakRef); + return observer.forget(); + } + + const nsCString& GetDomain() const { return mDomain; } + + nsPrefBranch* GetPrefBranch() const { return mBranch; } + + // Has this callback's weak reference died? + bool IsExpired() const { + if (!IsWeak()) return false; + + nsCOMPtr<nsIObserver> observer(do_QueryReferent(mWeakRef)); + return !observer; + } + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const { + size_t n = aMallocSizeOf(this); + n += mDomain.SizeOfExcludingThisIfUnshared(aMallocSizeOf); + + // All the other fields are non-owning pointers, so we don't measure them. + + return n; + } + + enum { ALLOW_MEMMOVE = true }; + + private: + nsCString mDomain; + nsPrefBranch* mBranch; + + // Exactly one of mWeakRef and mStrongRef should be non-null. + nsWeakPtr mWeakRef; + nsCOMPtr<nsIObserver> mStrongRef; + + // We need a canonical nsISupports pointer, per bug 578392. + nsISupports* mCanonical; + + bool IsWeak() const { return !!mWeakRef; } +}; + +class nsPrefBranch final : public nsIPrefBranch, + public nsIObserver, + public nsSupportsWeakReference { + friend class mozilla::PreferenceServiceReporter; + + public: + NS_DECL_ISUPPORTS + NS_DECL_NSIPREFBRANCH + NS_DECL_NSIOBSERVER + + nsPrefBranch(const char* aPrefRoot, PrefValueKind aKind); + nsPrefBranch() = delete; + + static void NotifyObserver(const char* aNewpref, void* aData); + + size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const; + + private: + using PrefName = nsCString; + + virtual ~nsPrefBranch(); + + int32_t GetRootLength() const { return mPrefRoot.Length(); } + + nsresult GetDefaultFromPropertiesFile(const char* aPrefName, + nsAString& aReturn); + + // As SetCharPref, but without any check on the length of |aValue|. + nsresult SetCharPrefNoLengthCheck(const char* aPrefName, + const nsACString& aValue); + + // Reject strings that are more than 1Mb, warn if strings are more than 16kb. + nsresult CheckSanityOfStringLength(const char* aPrefName, + const nsAString& aValue); + nsresult CheckSanityOfStringLength(const char* aPrefName, + const nsACString& aValue); + nsresult CheckSanityOfStringLength(const char* aPrefName, + const uint32_t aLength); + + void RemoveExpiredCallback(PrefCallback* aCallback); + + PrefName GetPrefName(const char* aPrefName) const { + return GetPrefName(nsDependentCString(aPrefName)); + } + + PrefName GetPrefName(const nsACString& aPrefName) const; + + void FreeObserverList(void); + + const nsCString mPrefRoot; + PrefValueKind mKind; + + bool mFreeingObserverList; + nsClassHashtable<PrefCallback, PrefCallback> mObservers; +}; + +class nsPrefLocalizedString final : public nsIPrefLocalizedString { + public: + nsPrefLocalizedString(); + + NS_DECL_ISUPPORTS + NS_FORWARD_NSISUPPORTSPRIMITIVE(mUnicodeString->) + NS_FORWARD_NSISUPPORTSSTRING(mUnicodeString->) + + nsresult Init(); + + private: + virtual ~nsPrefLocalizedString(); + + nsCOMPtr<nsISupportsString> mUnicodeString; +}; + +//---------------------------------------------------------------------------- +// nsPrefBranch +//---------------------------------------------------------------------------- + +nsPrefBranch::nsPrefBranch(const char* aPrefRoot, PrefValueKind aKind) + : mPrefRoot(aPrefRoot), + mKind(aKind), + mFreeingObserverList(false), + mObservers() { + nsCOMPtr<nsIObserverService> observerService = services::GetObserverService(); + if (observerService) { + ++mRefCnt; // must be > 0 when we call this, or we'll get deleted! + + // Add weakly so we don't have to clean up at shutdown. + observerService->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, true); + --mRefCnt; + } +} + +nsPrefBranch::~nsPrefBranch() { FreeObserverList(); } + +NS_IMPL_ISUPPORTS(nsPrefBranch, nsIPrefBranch, nsIObserver, + nsISupportsWeakReference) + +NS_IMETHODIMP +nsPrefBranch::GetRoot(nsACString& aRoot) { + aRoot = mPrefRoot; + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::GetPrefType(const char* aPrefName, int32_t* aRetVal) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& prefName = GetPrefName(aPrefName); + *aRetVal = Preferences::GetType(prefName.get()); + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::GetBoolPrefWithDefault(const char* aPrefName, bool aDefaultValue, + uint8_t aArgc, bool* aRetVal) { + nsresult rv = GetBoolPref(aPrefName, aRetVal); + if (NS_FAILED(rv) && aArgc == 1) { + *aRetVal = aDefaultValue; + return NS_OK; + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::GetBoolPref(const char* aPrefName, bool* aRetVal) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::GetBool(pref.get(), aRetVal, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::SetBoolPref(const char* aPrefName, bool aValue) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::SetBool(pref.get(), aValue, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::GetFloatPrefWithDefault(const char* aPrefName, + float aDefaultValue, uint8_t aArgc, + float* aRetVal) { + nsresult rv = GetFloatPref(aPrefName, aRetVal); + + if (NS_FAILED(rv) && aArgc == 1) { + *aRetVal = aDefaultValue; + return NS_OK; + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::GetFloatPref(const char* aPrefName, float* aRetVal) { + NS_ENSURE_ARG(aPrefName); + + nsAutoCString stringVal; + nsresult rv = GetCharPref(aPrefName, stringVal); + if (NS_SUCCEEDED(rv)) { + // ToFloat() does a locale-independent conversion. + *aRetVal = stringVal.ToFloat(&rv); + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::GetCharPrefWithDefault(const char* aPrefName, + const nsACString& aDefaultValue, + uint8_t aArgc, nsACString& aRetVal) { + nsresult rv = GetCharPref(aPrefName, aRetVal); + + if (NS_FAILED(rv) && aArgc == 1) { + aRetVal = aDefaultValue; + return NS_OK; + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::GetCharPref(const char* aPrefName, nsACString& aRetVal) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::GetCString(pref.get(), aRetVal, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::SetCharPref(const char* aPrefName, const nsACString& aValue) { + nsresult rv = CheckSanityOfStringLength(aPrefName, aValue); + if (NS_FAILED(rv)) { + return rv; + } + return SetCharPrefNoLengthCheck(aPrefName, aValue); +} + +nsresult nsPrefBranch::SetCharPrefNoLengthCheck(const char* aPrefName, + const nsACString& aValue) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::SetCString(pref.get(), aValue, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::GetStringPref(const char* aPrefName, + const nsACString& aDefaultValue, uint8_t aArgc, + nsACString& aRetVal) { + nsCString utf8String; + nsresult rv = GetCharPref(aPrefName, utf8String); + if (NS_SUCCEEDED(rv)) { + aRetVal = utf8String; + return rv; + } + + if (aArgc == 1) { + aRetVal = aDefaultValue; + return NS_OK; + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::SetStringPref(const char* aPrefName, const nsACString& aValue) { + nsresult rv = CheckSanityOfStringLength(aPrefName, aValue); + if (NS_FAILED(rv)) { + return rv; + } + + return SetCharPrefNoLengthCheck(aPrefName, aValue); +} + +NS_IMETHODIMP +nsPrefBranch::GetIntPrefWithDefault(const char* aPrefName, + int32_t aDefaultValue, uint8_t aArgc, + int32_t* aRetVal) { + nsresult rv = GetIntPref(aPrefName, aRetVal); + + if (NS_FAILED(rv) && aArgc == 1) { + *aRetVal = aDefaultValue; + return NS_OK; + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::GetIntPref(const char* aPrefName, int32_t* aRetVal) { + NS_ENSURE_ARG(aPrefName); + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::GetInt(pref.get(), aRetVal, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::SetIntPref(const char* aPrefName, int32_t aValue) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::SetInt(pref.get(), aValue, mKind); +} + +NS_IMETHODIMP +nsPrefBranch::GetComplexValue(const char* aPrefName, const nsIID& aType, + void** aRetVal) { + NS_ENSURE_ARG(aPrefName); + + nsresult rv; + nsAutoCString utf8String; + + // We have to do this one first because it's different to all the rest. + if (aType.Equals(NS_GET_IID(nsIPrefLocalizedString))) { + nsCOMPtr<nsIPrefLocalizedString> theString( + do_CreateInstance(NS_PREFLOCALIZEDSTRING_CONTRACTID, &rv)); + if (NS_FAILED(rv)) { + return rv; + } + + const PrefName& pref = GetPrefName(aPrefName); + bool bNeedDefault = false; + + if (mKind == PrefValueKind::Default) { + bNeedDefault = true; + } else { + // if there is no user (or locked) value + if (!Preferences::HasUserValue(pref.get()) && + !Preferences::IsLocked(pref.get())) { + bNeedDefault = true; + } + } + + // if we need to fetch the default value, do that instead, otherwise use the + // value we pulled in at the top of this function + if (bNeedDefault) { + nsAutoString utf16String; + rv = GetDefaultFromPropertiesFile(pref.get(), utf16String); + if (NS_SUCCEEDED(rv)) { + theString->SetData(utf16String); + } + } else { + rv = GetCharPref(aPrefName, utf8String); + if (NS_SUCCEEDED(rv)) { + theString->SetData(NS_ConvertUTF8toUTF16(utf8String)); + } + } + + if (NS_SUCCEEDED(rv)) { + theString.forget(reinterpret_cast<nsIPrefLocalizedString**>(aRetVal)); + } + + return rv; + } + + // if we can't get the pref, there's no point in being here + rv = GetCharPref(aPrefName, utf8String); + if (NS_FAILED(rv)) { + return rv; + } + + if (aType.Equals(NS_GET_IID(nsIFile))) { + ENSURE_PARENT_PROCESS("GetComplexValue(nsIFile)", aPrefName); + + nsCOMPtr<nsIFile> file(do_CreateInstance(NS_LOCAL_FILE_CONTRACTID, &rv)); + + if (NS_SUCCEEDED(rv)) { + rv = file->SetPersistentDescriptor(utf8String); + if (NS_SUCCEEDED(rv)) { + file.forget(reinterpret_cast<nsIFile**>(aRetVal)); + return NS_OK; + } + } + return rv; + } + + if (aType.Equals(NS_GET_IID(nsIRelativeFilePref))) { + ENSURE_PARENT_PROCESS("GetComplexValue(nsIRelativeFilePref)", aPrefName); + + nsACString::const_iterator keyBegin, strEnd; + utf8String.BeginReading(keyBegin); + utf8String.EndReading(strEnd); + + // The pref has the format: [fromKey]a/b/c + if (*keyBegin++ != '[') { + return NS_ERROR_FAILURE; + } + + nsACString::const_iterator keyEnd(keyBegin); + if (!FindCharInReadable(']', keyEnd, strEnd)) { + return NS_ERROR_FAILURE; + } + + nsAutoCString key(Substring(keyBegin, keyEnd)); + + nsCOMPtr<nsIFile> fromFile; + nsCOMPtr<nsIProperties> directoryService( + do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv)); + if (NS_FAILED(rv)) { + return rv; + } + + rv = directoryService->Get(key.get(), NS_GET_IID(nsIFile), + getter_AddRefs(fromFile)); + if (NS_FAILED(rv)) { + return rv; + } + + nsCOMPtr<nsIFile> theFile; + rv = NS_NewNativeLocalFile(""_ns, true, getter_AddRefs(theFile)); + if (NS_FAILED(rv)) { + return rv; + } + + rv = theFile->SetRelativeDescriptor(fromFile, Substring(++keyEnd, strEnd)); + if (NS_FAILED(rv)) { + return rv; + } + + nsCOMPtr<nsIRelativeFilePref> relativePref = new nsRelativeFilePref(); + Unused << relativePref->SetFile(theFile); + Unused << relativePref->SetRelativeToKey(key); + + relativePref.forget(reinterpret_cast<nsIRelativeFilePref**>(aRetVal)); + return NS_OK; + } + + NS_WARNING("nsPrefBranch::GetComplexValue - Unsupported interface type"); + return NS_NOINTERFACE; +} + +nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, + const nsAString& aValue) { + return CheckSanityOfStringLength(aPrefName, aValue.Length()); +} + +nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, + const nsACString& aValue) { + return CheckSanityOfStringLength(aPrefName, aValue.Length()); +} + +nsresult nsPrefBranch::CheckSanityOfStringLength(const char* aPrefName, + const uint32_t aLength) { + if (aLength > MAX_PREF_LENGTH) { + return NS_ERROR_ILLEGAL_VALUE; + } + if (aLength <= MAX_ADVISABLE_PREF_LENGTH) { + return NS_OK; + } + + nsresult rv; + nsCOMPtr<nsIConsoleService> console = + do_GetService("@mozilla.org/consoleservice;1", &rv); + if (NS_FAILED(rv)) { + return rv; + } + + nsAutoCString message(nsPrintfCString( + "Warning: attempting to write %d bytes to preference %s. This is bad " + "for general performance and memory usage. Such an amount of data " + "should rather be written to an external file. This preference will " + "not be sent to any content processes.", + aLength, GetPrefName(aPrefName).get())); + + rv = console->LogStringMessage(NS_ConvertUTF8toUTF16(message).get()); + if (NS_FAILED(rv)) { + return rv; + } + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::SetComplexValue(const char* aPrefName, const nsIID& aType, + nsISupports* aValue) { + ENSURE_PARENT_PROCESS("SetComplexValue", aPrefName); + NS_ENSURE_ARG(aPrefName); + + nsresult rv = NS_NOINTERFACE; + + if (aType.Equals(NS_GET_IID(nsIFile))) { + nsCOMPtr<nsIFile> file = do_QueryInterface(aValue); + if (!file) { + return NS_NOINTERFACE; + } + + nsAutoCString descriptorString; + rv = file->GetPersistentDescriptor(descriptorString); + if (NS_SUCCEEDED(rv)) { + rv = SetCharPrefNoLengthCheck(aPrefName, descriptorString); + } + return rv; + } + + if (aType.Equals(NS_GET_IID(nsIRelativeFilePref))) { + nsCOMPtr<nsIRelativeFilePref> relFilePref = do_QueryInterface(aValue); + if (!relFilePref) { + return NS_NOINTERFACE; + } + + nsCOMPtr<nsIFile> file; + relFilePref->GetFile(getter_AddRefs(file)); + if (!file) { + return NS_NOINTERFACE; + } + + nsAutoCString relativeToKey; + (void)relFilePref->GetRelativeToKey(relativeToKey); + + nsCOMPtr<nsIFile> relativeToFile; + nsCOMPtr<nsIProperties> directoryService( + do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv)); + if (NS_FAILED(rv)) { + return rv; + } + + rv = directoryService->Get(relativeToKey.get(), NS_GET_IID(nsIFile), + getter_AddRefs(relativeToFile)); + if (NS_FAILED(rv)) { + return rv; + } + + nsAutoCString relDescriptor; + rv = file->GetRelativeDescriptor(relativeToFile, relDescriptor); + if (NS_FAILED(rv)) { + return rv; + } + + nsAutoCString descriptorString; + descriptorString.Append('['); + descriptorString.Append(relativeToKey); + descriptorString.Append(']'); + descriptorString.Append(relDescriptor); + return SetCharPrefNoLengthCheck(aPrefName, descriptorString); + } + + if (aType.Equals(NS_GET_IID(nsIPrefLocalizedString))) { + nsCOMPtr<nsISupportsString> theString = do_QueryInterface(aValue); + + if (theString) { + nsString wideString; + + rv = theString->GetData(wideString); + if (NS_SUCCEEDED(rv)) { + // Check sanity of string length before any lengthy conversion + rv = CheckSanityOfStringLength(aPrefName, wideString); + if (NS_FAILED(rv)) { + return rv; + } + rv = SetCharPrefNoLengthCheck(aPrefName, + NS_ConvertUTF16toUTF8(wideString)); + } + } + return rv; + } + + NS_WARNING("nsPrefBranch::SetComplexValue - Unsupported interface type"); + return NS_NOINTERFACE; +} + +NS_IMETHODIMP +nsPrefBranch::ClearUserPref(const char* aPrefName) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::ClearUser(pref.get()); +} + +NS_IMETHODIMP +nsPrefBranch::PrefHasUserValue(const char* aPrefName, bool* aRetVal) { + NS_ENSURE_ARG_POINTER(aRetVal); + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + *aRetVal = Preferences::HasUserValue(pref.get()); + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::LockPref(const char* aPrefName) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::Lock(pref.get()); +} + +NS_IMETHODIMP +nsPrefBranch::PrefIsLocked(const char* aPrefName, bool* aRetVal) { + NS_ENSURE_ARG_POINTER(aRetVal); + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + *aRetVal = Preferences::IsLocked(pref.get()); + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::UnlockPref(const char* aPrefName) { + NS_ENSURE_ARG(aPrefName); + + const PrefName& pref = GetPrefName(aPrefName); + return Preferences::Unlock(pref.get()); +} + +NS_IMETHODIMP +nsPrefBranch::ResetBranch(const char* aStartingAt) { + return NS_ERROR_NOT_IMPLEMENTED; +} + +NS_IMETHODIMP +nsPrefBranch::DeleteBranch(const char* aStartingAt) { + ENSURE_PARENT_PROCESS("DeleteBranch", aStartingAt); + NS_ENSURE_ARG(aStartingAt); + + MOZ_ASSERT(NS_IsMainThread()); + + if (!HashTable()) { + return NS_ERROR_NOT_INITIALIZED; + } + + const PrefName& pref = GetPrefName(aStartingAt); + nsAutoCString branchName(pref.get()); + + // Add a trailing '.' if it doesn't already have one. + if (branchName.Length() > 1 && !StringEndsWith(branchName, "."_ns)) { + branchName += '.'; + } + + const nsACString& branchNameNoDot = + Substring(branchName, 0, branchName.Length() - 1); + + for (auto iter = HashTable()->modIter(); !iter.done(); iter.next()) { + // The first disjunct matches branches: e.g. a branch name "foo.bar." + // matches a name "foo.bar.baz" (but it won't match "foo.barrel.baz"). + // The second disjunct matches leaf nodes: e.g. a branch name "foo.bar." + // matches a name "foo.bar" (by ignoring the trailing '.'). + nsDependentCString name(iter.get()->Name()); + if (StringBeginsWith(name, branchName) || name.Equals(branchNameNoDot)) { + iter.remove(); + // The saved callback pref may be invalid now. + gCallbackPref = nullptr; + } + } + + Preferences::HandleDirty(); + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::GetChildList(const char* aStartingAt, + nsTArray<nsCString>& aChildArray) { + NS_ENSURE_ARG(aStartingAt); + + MOZ_ASSERT(NS_IsMainThread()); + + // This will contain a list of all the pref name strings. Allocated on the + // stack for speed. + AutoTArray<nsCString, 32> prefArray; + + const PrefName& parent = GetPrefName(aStartingAt); + size_t parentLen = parent.Length(); + for (auto& pref : PrefsIter(HashTable(), gSharedMap)) { + if (strncmp(pref->Name(), parent.get(), parentLen) == 0) { + prefArray.AppendElement(pref->NameString()); + } + } + + // Now that we've built up the list, run the callback on all the matching + // elements. + aChildArray.SetCapacity(prefArray.Length()); + for (auto& element : prefArray) { + // we need to lop off mPrefRoot in case the user is planning to pass this + // back to us because if they do we are going to add mPrefRoot again. + aChildArray.AppendElement(Substring(element, mPrefRoot.Length())); + } + + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::AddObserverImpl(const nsACString& aDomain, nsIObserver* aObserver, + bool aHoldWeak) { + PrefCallback* pCallback; + + NS_ENSURE_ARG(aObserver); + + const nsCString& prefName = GetPrefName(aDomain); + + // Hold a weak reference to the observer if so requested. + if (aHoldWeak) { + nsCOMPtr<nsISupportsWeakReference> weakRefFactory = + do_QueryInterface(aObserver); + if (!weakRefFactory) { + // The caller didn't give us a object that supports weak reference... + // tell them. + return NS_ERROR_INVALID_ARG; + } + + // Construct a PrefCallback with a weak reference to the observer. + pCallback = new PrefCallback(prefName, weakRefFactory, this); + + } else { + // Construct a PrefCallback with a strong reference to the observer. + pCallback = new PrefCallback(prefName, aObserver, this); + } + + auto p = mObservers.LookupForAdd(pCallback); + if (p) { + NS_WARNING("Ignoring duplicate observer."); + delete pCallback; + return NS_OK; + } + + p.OrInsert([&pCallback]() { return pCallback; }); + + // We must pass a fully qualified preference name to the callback + // aDomain == nullptr is the only possible failure, and we trapped it with + // NS_ENSURE_ARG above. + Preferences::RegisterCallback(NotifyObserver, prefName, pCallback, + Preferences::PrefixMatch, + /* isPriority */ false); + + return NS_OK; +} + +NS_IMETHODIMP +nsPrefBranch::RemoveObserverImpl(const nsACString& aDomain, + nsIObserver* aObserver) { + NS_ENSURE_ARG(aObserver); + + nsresult rv = NS_OK; + + // If we're in the middle of a call to FreeObserverList, don't process this + // RemoveObserver call -- the observer in question will be removed soon, if + // it hasn't been already. + // + // It's important that we don't touch mObservers in any way -- even a Get() + // which returns null might cause the hashtable to resize itself, which will + // break the iteration in FreeObserverList. + if (mFreeingObserverList) { + return NS_OK; + } + + // Remove the relevant PrefCallback from mObservers and get an owning pointer + // to it. Unregister the callback first, and then let the owning pointer go + // out of scope and destroy the callback. + const nsCString& prefName = GetPrefName(aDomain); + PrefCallback key(prefName, aObserver, this); + mozilla::UniquePtr<PrefCallback> pCallback; + mObservers.Remove(&key, &pCallback); + if (pCallback) { + rv = Preferences::UnregisterCallback( + NotifyObserver, prefName, pCallback.get(), Preferences::PrefixMatch); + } + + return rv; +} + +NS_IMETHODIMP +nsPrefBranch::Observe(nsISupports* aSubject, const char* aTopic, + const char16_t* aData) { + // Watch for xpcom shutdown and free our observers to eliminate any cyclic + // references. + if (!nsCRT::strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) { + FreeObserverList(); + } + return NS_OK; +} + +/* static */ +void nsPrefBranch::NotifyObserver(const char* aNewPref, void* aData) { + PrefCallback* pCallback = (PrefCallback*)aData; + + nsCOMPtr<nsIObserver> observer = pCallback->GetObserver(); + if (!observer) { + // The observer has expired. Let's remove this callback. + pCallback->GetPrefBranch()->RemoveExpiredCallback(pCallback); + return; + } + + // Remove any root this string may contain so as to not confuse the observer + // by passing them something other than what they passed us as a topic. + uint32_t len = pCallback->GetPrefBranch()->GetRootLength(); + nsDependentCString suffix(aNewPref + len); + + observer->Observe(static_cast<nsIPrefBranch*>(pCallback->GetPrefBranch()), + NS_PREFBRANCH_PREFCHANGE_TOPIC_ID, + NS_ConvertASCIItoUTF16(suffix).get()); +} + +size_t nsPrefBranch::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const { + size_t n = aMallocSizeOf(this); + + n += mPrefRoot.SizeOfExcludingThisIfUnshared(aMallocSizeOf); + + n += mObservers.ShallowSizeOfExcludingThis(aMallocSizeOf); + for (auto iter = mObservers.ConstIter(); !iter.Done(); iter.Next()) { + const PrefCallback* data = iter.UserData(); + n += data->SizeOfIncludingThis(aMallocSizeOf); + } + + return n; +} + +void nsPrefBranch::FreeObserverList() { + // We need to prevent anyone from modifying mObservers while we're iterating + // over it. In particular, some clients will call RemoveObserver() when + // they're removed and destructed via the iterator; we set + // mFreeingObserverList to keep those calls from touching mObservers. + mFreeingObserverList = true; + for (auto iter = mObservers.Iter(); !iter.Done(); iter.Next()) { + auto callback = iter.UserData(); + Preferences::UnregisterCallback(nsPrefBranch::NotifyObserver, + callback->GetDomain(), callback, + Preferences::PrefixMatch); + iter.Remove(); + } + + nsCOMPtr<nsIObserverService> observerService = services::GetObserverService(); + if (observerService) { + observerService->RemoveObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID); + } + + mFreeingObserverList = false; +} + +void nsPrefBranch::RemoveExpiredCallback(PrefCallback* aCallback) { + MOZ_ASSERT(aCallback->IsExpired()); + mObservers.Remove(aCallback); +} + +nsresult nsPrefBranch::GetDefaultFromPropertiesFile(const char* aPrefName, + nsAString& aReturn) { + // The default value contains a URL to a .properties file. + + nsAutoCString propertyFileURL; + nsresult rv = Preferences::GetCString(aPrefName, propertyFileURL, + PrefValueKind::Default); + if (NS_FAILED(rv)) { + return rv; + } + + nsCOMPtr<nsIStringBundleService> bundleService = + services::GetStringBundleService(); + if (!bundleService) { + return NS_ERROR_FAILURE; + } + + nsCOMPtr<nsIStringBundle> bundle; + rv = bundleService->CreateBundle(propertyFileURL.get(), + getter_AddRefs(bundle)); + if (NS_FAILED(rv)) { + return rv; + } + + return bundle->GetStringFromName(aPrefName, aReturn); +} + +nsPrefBranch::PrefName nsPrefBranch::GetPrefName( + const nsACString& aPrefName) const { + if (mPrefRoot.IsEmpty()) { + return PrefName(PromiseFlatCString(aPrefName)); + } + + return PrefName(mPrefRoot + aPrefName); +} + +//---------------------------------------------------------------------------- +// nsPrefLocalizedString +//---------------------------------------------------------------------------- + +nsPrefLocalizedString::nsPrefLocalizedString() = default; + +nsPrefLocalizedString::~nsPrefLocalizedString() = default; + +NS_IMPL_ISUPPORTS(nsPrefLocalizedString, nsIPrefLocalizedString, + nsISupportsString) + +nsresult nsPrefLocalizedString::Init() { + nsresult rv; + mUnicodeString = do_CreateInstance(NS_SUPPORTS_STRING_CONTRACTID, &rv); + + return rv; +} + +//---------------------------------------------------------------------------- +// nsRelativeFilePref +//---------------------------------------------------------------------------- + +NS_IMPL_ISUPPORTS(nsRelativeFilePref, nsIRelativeFilePref) + +nsRelativeFilePref::nsRelativeFilePref() = default; + +nsRelativeFilePref::~nsRelativeFilePref() = default; + +NS_IMETHODIMP +nsRelativeFilePref::GetFile(nsIFile** aFile) { + NS_ENSURE_ARG_POINTER(aFile); + *aFile = mFile; + NS_IF_ADDREF(*aFile); + return NS_OK; +} + +NS_IMETHODIMP +nsRelativeFilePref::SetFile(nsIFile* aFile) { + mFile = aFile; + return NS_OK; +} + +NS_IMETHODIMP +nsRelativeFilePref::GetRelativeToKey(nsACString& aRelativeToKey) { + aRelativeToKey.Assign(mRelativeToKey); + return NS_OK; +} + +NS_IMETHODIMP +nsRelativeFilePref::SetRelativeToKey(const nsACString& aRelativeToKey) { + mRelativeToKey.Assign(aRelativeToKey); + return NS_OK; +} + +//=========================================================================== +// class Preferences and related things +//=========================================================================== + +namespace mozilla { + +#define INITIAL_PREF_FILES 10 + +static NS_DEFINE_CID(kZipReaderCID, NS_ZIPREADER_CID); + +void Preferences::HandleDirty() { + MOZ_ASSERT(XRE_IsParentProcess()); + + if (!HashTable() || !sPreferences) { + return; + } + + if (sPreferences->mProfileShutdown) { + NS_WARNING("Setting user pref after profile shutdown."); + return; + } + + if (!sPreferences->mDirty) { + sPreferences->mDirty = true; + + if (sPreferences->mCurrentFile && sPreferences->AllowOffMainThreadSave() && + !sPreferences->mSavePending) { + sPreferences->mSavePending = true; + static const int PREF_DELAY_MS = 500; + NS_DelayedDispatchToCurrentThread( + NewRunnableMethod("Preferences::SavePrefFileAsynchronous", + sPreferences.get(), + &Preferences::SavePrefFileAsynchronous), + PREF_DELAY_MS); + } + } +} + +static nsresult openPrefFile(nsIFile* aFile, PrefValueKind aKind); + +static nsresult parsePrefData(const nsCString& aData, PrefValueKind aKind); + +// clang-format off +static const char kPrefFileHeader[] = + "// Mozilla User Preferences" + NS_LINEBREAK + NS_LINEBREAK + "// DO NOT EDIT THIS FILE." + NS_LINEBREAK + "//" + NS_LINEBREAK + "// If you make changes to this file while the application is running," + NS_LINEBREAK + "// the changes will be overwritten when the application exits." + NS_LINEBREAK + "//" + NS_LINEBREAK + "// To change a preference value, you can either:" + NS_LINEBREAK + "// - modify it via the UI (e.g. via about:config in the browser); or" + NS_LINEBREAK + "// - set it within a user.js file in your profile." + NS_LINEBREAK + NS_LINEBREAK; +// clang-format on + +// Note: if sShutdown is true, sPreferences will be nullptr. +StaticRefPtr<Preferences> Preferences::sPreferences; +bool Preferences::sShutdown = false; + +// This globally enables or disables OMT pref writing, both sync and async. +static int32_t sAllowOMTPrefWrite = -1; + +// Write the preference data to a file. +class PreferencesWriter final { + public: + PreferencesWriter() = default; + + static nsresult Write(nsIFile* aFile, PrefSaveData& aPrefs) { + nsCOMPtr<nsIOutputStream> outStreamSink; + nsCOMPtr<nsIOutputStream> outStream; + uint32_t writeAmount; + nsresult rv; + + // Execute a "safe" save by saving through a tempfile. + rv = NS_NewSafeLocalFileOutputStream(getter_AddRefs(outStreamSink), aFile, + -1, 0600); + if (NS_FAILED(rv)) { + return rv; + } + + rv = NS_NewBufferedOutputStream(getter_AddRefs(outStream), + outStreamSink.forget(), 4096); + if (NS_FAILED(rv)) { + return rv; + } + + struct CharComparator { + bool LessThan(const nsCString& aA, const nsCString& aB) const { + return aA < aB; + } + + bool Equals(const nsCString& aA, const nsCString& aB) const { + return aA == aB; + } + }; + + // Sort the preferences to make a readable file on disk. + aPrefs.Sort(CharComparator()); + + // Write out the file header. + outStream->Write(kPrefFileHeader, sizeof(kPrefFileHeader) - 1, + &writeAmount); + + for (nsCString& pref : aPrefs) { + outStream->Write(pref.get(), pref.Length(), &writeAmount); + outStream->Write(NS_LINEBREAK, NS_LINEBREAK_LEN, &writeAmount); + } + + // Tell the safe output stream to overwrite the real prefs file. + // (It'll abort if there were any errors during writing.) + nsCOMPtr<nsISafeOutputStream> safeStream = do_QueryInterface(outStream); + MOZ_ASSERT(safeStream, "expected a safe output stream!"); + if (safeStream) { + rv = safeStream->Finish(); + } + +#ifdef DEBUG + if (NS_FAILED(rv)) { + NS_WARNING("failed to save prefs file! possible data loss"); + } +#endif + + return rv; + } + + static void Flush() { + MOZ_DIAGNOSTIC_ASSERT(sPendingWriteCount >= 0); + // SpinEventLoopUntil is unfortunate, but ultimately it's the best thing + // we can do here given the constraint that we need to ensure that + // the preferences on disk match what we have in memory. We could + // easily perform the write here ourselves by doing exactly what + // happens in PWRunnable::Run. This would be the right thing to do + // if we're stuck here because other unrelated runnables are taking + // a long time, and the wrong thing to do if PreferencesWriter::Write + // is what takes a long time, as we would be trading a SpinEventLoopUntil + // for a synchronous disk write, wherein we could not even spin the + // event loop. Given that PWRunnable generally runs on a thread pool, + // if we're stuck here, it's likely because of PreferencesWriter::Write + // and not some other runnable. Thus, spin away. + mozilla::SpinEventLoopUntil([]() { return sPendingWriteCount <= 0; }); + } + + // This is the data that all of the runnables (see below) will attempt + // to write. It will always have the most up to date version, or be + // null, if the up to date information has already been written out. + static Atomic<PrefSaveData*> sPendingWriteData; + + // This is the number of writes via PWRunnables which have been dispatched + // but not yet completed. This is intended to be used by Flush to ensure + // that there are no outstanding writes left incomplete, and thus our prefs + // on disk are in sync with what we have in memory. + static Atomic<int> sPendingWriteCount; + + // See PWRunnable::Run for details on why we need this lock. + static StaticMutex sWritingToFile; +}; + +Atomic<PrefSaveData*> PreferencesWriter::sPendingWriteData(nullptr); +Atomic<int> PreferencesWriter::sPendingWriteCount(0); +StaticMutex PreferencesWriter::sWritingToFile; + +class PWRunnable : public Runnable { + public: + explicit PWRunnable(nsIFile* aFile) : Runnable("PWRunnable"), mFile(aFile) {} + + NS_IMETHOD Run() override { + // Preference writes are handled a bit strangely, in that a "newer" + // write is generally regarded as always better. For this reason, + // sPendingWriteData can be overwritten multiple times before anyone + // gets around to actually using it, minimizing writes. However, + // once we've acquired sPendingWriteData we've reached a + // "point of no return" and have to complete the write. + // + // Unfortunately, this design allows the following behaviour: + // + // 1. write1 is queued up + // 2. thread1 acquires write1 + // 3. write2 is queued up + // 4. thread2 acquires write2 + // 5. thread1 and thread2 concurrently clobber each other + // + // To avoid this, we use this lock to ensure that only one thread + // at a time is trying to acquire the write, and when it does, + // all other threads are prevented from acquiring writes until it + // completes the write. New writes are still allowed to be queued + // up in this time. + // + // Although it's atomic, the acquire needs to be guarded by the mutex + // to avoid reordering of writes -- we don't want an older write to + // run after a newer one. To avoid this causing too much waiting, we check + // if sPendingWriteData is already null before acquiring the mutex. If it + // is, then there's definitely no work to be done (or someone is in the + // middle of doing it for us). + // + // Note that every time a new write is queued up, a new write task is + // is also queued up, so there will always be a task that can see the newest + // write. + // + // Ideally this lock wouldn't be necessary, and the PreferencesWriter + // would be used more carefully, but it's hard to untangle all that. + nsresult rv = NS_OK; + if (PreferencesWriter::sPendingWriteData) { + StaticMutexAutoLock lock(PreferencesWriter::sWritingToFile); + // If we get a nullptr on the exchange, it means that somebody + // else has already processed the request, and we can just return. + UniquePtr<PrefSaveData> prefs( + PreferencesWriter::sPendingWriteData.exchange(nullptr)); + if (prefs) { + rv = PreferencesWriter::Write(mFile, *prefs); + // Make a copy of these so we can have them in runnable lambda. + // nsIFile is only there so that we would never release the + // ref counted pointer off main thread. + nsresult rvCopy = rv; + nsCOMPtr<nsIFile> fileCopy(mFile); + SchedulerGroup::Dispatch( + TaskCategory::Other, + NS_NewRunnableFunction("Preferences::WriterRunnable", + [fileCopy, rvCopy] { + MOZ_RELEASE_ASSERT(NS_IsMainThread()); + if (NS_FAILED(rvCopy)) { + Preferences::HandleDirty(); + } + })); + } + } + // We've completed the write to the best of our abilities, whether + // we had prefs to write or another runnable got to them first. If + // PreferencesWriter::Write failed, this is still correct as the + // write is no longer outstanding, and the above HandleDirty call + // will just start the cycle again. + PreferencesWriter::sPendingWriteCount--; + return rv; + } + + protected: + nsCOMPtr<nsIFile> mFile; +}; + +// Although this is a member of Preferences, it measures sPreferences and +// several other global structures. +/* static */ +void Preferences::AddSizeOfIncludingThis(MallocSizeOf aMallocSizeOf, + PrefsSizes& aSizes) { + if (!sPreferences) { + return; + } + + aSizes.mMisc += aMallocSizeOf(sPreferences.get()); + + aSizes.mRootBranches += + static_cast<nsPrefBranch*>(sPreferences->mRootBranch.get()) + ->SizeOfIncludingThis(aMallocSizeOf) + + static_cast<nsPrefBranch*>(sPreferences->mDefaultRootBranch.get()) + ->SizeOfIncludingThis(aMallocSizeOf); +} + +class PreferenceServiceReporter final : public nsIMemoryReporter { + ~PreferenceServiceReporter() {} + + public: + NS_DECL_ISUPPORTS + NS_DECL_NSIMEMORYREPORTER + + protected: + static const uint32_t kSuspectReferentCount = 1000; +}; + +NS_IMPL_ISUPPORTS(PreferenceServiceReporter, nsIMemoryReporter) + +MOZ_DEFINE_MALLOC_SIZE_OF(PreferenceServiceMallocSizeOf) + +NS_IMETHODIMP +PreferenceServiceReporter::CollectReports( + nsIHandleReportCallback* aHandleReport, nsISupports* aData, + bool aAnonymize) { + MOZ_ASSERT(NS_IsMainThread()); + + MallocSizeOf mallocSizeOf = PreferenceServiceMallocSizeOf; + PrefsSizes sizes; + + Preferences::AddSizeOfIncludingThis(mallocSizeOf, sizes); + + if (HashTable()) { + sizes.mHashTable += HashTable()->shallowSizeOfIncludingThis(mallocSizeOf); + for (auto iter = HashTable()->iter(); !iter.done(); iter.next()) { + iter.get()->AddSizeOfIncludingThis(mallocSizeOf, sizes); + } + } + + sizes.mPrefNameArena += PrefNameArena().SizeOfExcludingThis(mallocSizeOf); + + for (CallbackNode* node = gFirstCallback; node; node = node->Next()) { + node->AddSizeOfIncludingThis(mallocSizeOf, sizes); + } + + if (gSharedMap) { + sizes.mMisc += mallocSizeOf(gSharedMap); + } + +#ifdef ACCESS_COUNTS + if (gAccessCounts) { + sizes.mMisc += gAccessCounts->ShallowSizeOfIncludingThis(mallocSizeOf); + } +#endif + + MOZ_COLLECT_REPORT("explicit/preferences/hash-table", KIND_HEAP, UNITS_BYTES, + sizes.mHashTable, "Memory used by libpref's hash table."); + + MOZ_COLLECT_REPORT("explicit/preferences/pref-values", KIND_HEAP, UNITS_BYTES, + sizes.mPrefValues, + "Memory used by PrefValues hanging off the hash table."); + + MOZ_COLLECT_REPORT("explicit/preferences/string-values", KIND_HEAP, + UNITS_BYTES, sizes.mStringValues, + "Memory used by libpref's string pref values."); + + MOZ_COLLECT_REPORT("explicit/preferences/root-branches", KIND_HEAP, + UNITS_BYTES, sizes.mRootBranches, + "Memory used by libpref's root branches."); + + MOZ_COLLECT_REPORT("explicit/preferences/pref-name-arena", KIND_HEAP, + UNITS_BYTES, sizes.mPrefNameArena, + "Memory used by libpref's arena for pref names."); + + MOZ_COLLECT_REPORT("explicit/preferences/callbacks/objects", KIND_HEAP, + UNITS_BYTES, sizes.mCallbacksObjects, + "Memory used by pref callback objects."); + + MOZ_COLLECT_REPORT("explicit/preferences/callbacks/domains", KIND_HEAP, + UNITS_BYTES, sizes.mCallbacksDomains, + "Memory used by pref callback domains (pref names and " + "prefixes)."); + + MOZ_COLLECT_REPORT("explicit/preferences/misc", KIND_HEAP, UNITS_BYTES, + sizes.mMisc, "Miscellaneous memory used by libpref."); + + if (gSharedMap) { + if (XRE_IsParentProcess()) { + MOZ_COLLECT_REPORT("explicit/preferences/shared-memory-map", KIND_NONHEAP, + UNITS_BYTES, gSharedMap->MapSize(), + "The shared memory mapping used to share a " + "snapshot of preference values across processes."); + } + } + + nsPrefBranch* rootBranch = + static_cast<nsPrefBranch*>(Preferences::GetRootBranch()); + if (!rootBranch) { + return NS_OK; + } + + size_t numStrong = 0; + size_t numWeakAlive = 0; + size_t numWeakDead = 0; + nsTArray<nsCString> suspectPreferences; + // Count of the number of referents for each preference. + nsDataHashtable<nsCStringHashKey, uint32_t> prefCounter; + + for (auto iter = rootBranch->mObservers.Iter(); !iter.Done(); iter.Next()) { + auto callback = iter.UserData(); + + if (callback->IsWeak()) { + nsCOMPtr<nsIObserver> callbackRef = do_QueryReferent(callback->mWeakRef); + if (callbackRef) { + numWeakAlive++; + } else { + numWeakDead++; + } + } else { + numStrong++; + } + + uint32_t oldCount = 0; + prefCounter.Get(callback->GetDomain(), &oldCount); + uint32_t currentCount = oldCount + 1; + prefCounter.Put(callback->GetDomain(), currentCount); + + // Keep track of preferences that have a suspiciously large number of + // referents (a symptom of a leak). + if (currentCount == kSuspectReferentCount) { + suspectPreferences.AppendElement(callback->GetDomain()); + } + } + + for (uint32_t i = 0; i < suspectPreferences.Length(); i++) { + nsCString& suspect = suspectPreferences[i]; + uint32_t totalReferentCount = 0; + prefCounter.Get(suspect, &totalReferentCount); + + nsPrintfCString suspectPath( + "preference-service-suspect/" + "referent(pref=%s)", + suspect.get()); + + aHandleReport->Callback( + /* process = */ ""_ns, suspectPath, KIND_OTHER, UNITS_COUNT, + totalReferentCount, + "A preference with a suspiciously large number " + "referents (symptom of a leak)."_ns, + aData); + } + + MOZ_COLLECT_REPORT( + "preference-service/referent/strong", KIND_OTHER, UNITS_COUNT, numStrong, + "The number of strong referents held by the preference service."); + + MOZ_COLLECT_REPORT( + "preference-service/referent/weak/alive", KIND_OTHER, UNITS_COUNT, + numWeakAlive, + "The number of weak referents held by the preference service that are " + "still alive."); + + MOZ_COLLECT_REPORT( + "preference-service/referent/weak/dead", KIND_OTHER, UNITS_COUNT, + numWeakDead, + "The number of weak referents held by the preference service that are " + "dead."); + + return NS_OK; +} + +namespace { + +class AddPreferencesMemoryReporterRunnable : public Runnable { + public: + AddPreferencesMemoryReporterRunnable() + : Runnable("AddPreferencesMemoryReporterRunnable") {} + + NS_IMETHOD Run() override { + return RegisterStrongMemoryReporter(new PreferenceServiceReporter()); + } +}; + +} // namespace + +// A list of changed prefs sent from the parent via shared memory. +static nsTArray<dom::Pref>* gChangedDomPrefs; + +static const char kTelemetryPref[] = "toolkit.telemetry.enabled"; +static const char kChannelPref[] = "app.update.channel"; + +#ifdef MOZ_WIDGET_ANDROID + +static Maybe<bool> TelemetryPrefValue() { + // Leave it unchanged if it's already set. + // XXX: how could it already be set? + if (Preferences::GetType(kTelemetryPref) != nsIPrefBranch::PREF_INVALID) { + return Nothing(); + } + + // Determine the correct default for toolkit.telemetry.enabled. If this + // build has MOZ_TELEMETRY_ON_BY_DEFAULT *or* we're on the beta channel, + // telemetry is on by default, otherwise not. This is necessary so that + // beta users who are testing final release builds don't flipflop defaults. +# ifdef MOZ_TELEMETRY_ON_BY_DEFAULT + return Some(true); +# else + nsAutoCString channelPrefValue; + Unused << Preferences::GetCString(kChannelPref, channelPrefValue, + PrefValueKind::Default); + return Some(channelPrefValue.EqualsLiteral("beta")); +# endif +} + +/* static */ +void Preferences::SetupTelemetryPref() { + MOZ_ASSERT(XRE_IsParentProcess()); + + Maybe<bool> telemetryPrefValue = TelemetryPrefValue(); + if (telemetryPrefValue.isSome()) { + Preferences::SetBool(kTelemetryPref, *telemetryPrefValue, + PrefValueKind::Default); + } +} + +#else // !MOZ_WIDGET_ANDROID + +static bool TelemetryPrefValue() { + // For platforms with Unified Telemetry (here meaning not-Android), + // toolkit.telemetry.enabled determines whether we send "extended" data. + // We only want extended data from pre-release channels due to size. + + constexpr auto channel = MOZ_STRINGIFY(MOZ_UPDATE_CHANNEL) ""_ns; + + // Easy cases: Nightly, Aurora, Beta. + if (channel.EqualsLiteral("nightly") || channel.EqualsLiteral("aurora") || + channel.EqualsLiteral("beta")) { + return true; + } + +# ifndef MOZILLA_OFFICIAL + // Local developer builds: non-official builds on the "default" channel. + if (channel.EqualsLiteral("default")) { + return true; + } +# endif + + // Release Candidate builds: builds that think they are release builds, but + // are shipped to beta users. + if (channel.EqualsLiteral("release")) { + nsAutoCString channelPrefValue; + Unused << Preferences::GetCString(kChannelPref, channelPrefValue, + PrefValueKind::Default); + if (channelPrefValue.EqualsLiteral("beta")) { + return true; + } + } + + return false; +} + +/* static */ +void Preferences::SetupTelemetryPref() { + MOZ_ASSERT(XRE_IsParentProcess()); + + Preferences::SetBool(kTelemetryPref, TelemetryPrefValue(), + PrefValueKind::Default); + Preferences::Lock(kTelemetryPref); +} + +static void CheckTelemetryPref() { + MOZ_ASSERT(!XRE_IsParentProcess()); + + // Make sure the children got passed the right telemetry pref details. + DebugOnly<bool> value; + MOZ_ASSERT(NS_SUCCEEDED(Preferences::GetBool(kTelemetryPref, &value)) && + value == TelemetryPrefValue()); + MOZ_ASSERT(Preferences::IsLocked(kTelemetryPref)); +} + +#endif // MOZ_WIDGET_ANDROID + +/* static */ +already_AddRefed<Preferences> Preferences::GetInstanceForService() { + if (sPreferences) { + return do_AddRef(sPreferences); + } + + if (sShutdown) { + return nullptr; + } + + sPreferences = new Preferences(); + + MOZ_ASSERT(!HashTable()); + HashTable() = new PrefsHashTable(XRE_IsParentProcess() + ? kHashTableInitialLengthParent + : kHashTableInitialLengthContent); + +#ifdef DEBUG + gOnceStaticPrefsAntiFootgun = new AntiFootgunMap(); +#endif + +#ifdef ACCESS_COUNTS + MOZ_ASSERT(!gAccessCounts); + gAccessCounts = new AccessCountsHashTable(); +#endif + + nsresult rv = InitInitialObjects(/* isStartup */ true); + if (NS_FAILED(rv)) { + sPreferences = nullptr; + return nullptr; + } + + if (!XRE_IsParentProcess()) { + MOZ_ASSERT(gChangedDomPrefs); + for (unsigned int i = 0; i < gChangedDomPrefs->Length(); i++) { + Preferences::SetPreference(gChangedDomPrefs->ElementAt(i)); + } + delete gChangedDomPrefs; + gChangedDomPrefs = nullptr; + +#ifndef MOZ_WIDGET_ANDROID + CheckTelemetryPref(); +#endif + + } else { + // Check if there is a deployment configuration file. If so, set up the + // pref config machinery, which will actually read the file. + nsAutoCString lockFileName; + nsresult rv = Preferences::GetCString("general.config.filename", + lockFileName, PrefValueKind::User); + if (NS_SUCCEEDED(rv)) { + NS_CreateServicesFromCategory( + "pref-config-startup", + static_cast<nsISupports*>(static_cast<void*>(sPreferences)), + "pref-config-startup"); + } + + nsCOMPtr<nsIObserverService> observerService = + services::GetObserverService(); + if (!observerService) { + sPreferences = nullptr; + return nullptr; + } + + observerService->AddObserver(sPreferences, + "profile-before-change-telemetry", true); + rv = observerService->AddObserver(sPreferences, "profile-before-change", + true); + + observerService->AddObserver(sPreferences, "suspend_process_notification", + true); + + if (NS_FAILED(rv)) { + sPreferences = nullptr; + return nullptr; + } + } + + const char* defaultPrefs = getenv("MOZ_DEFAULT_PREFS"); + if (defaultPrefs) { + parsePrefData(nsCString(defaultPrefs), PrefValueKind::Default); + } + + // Preferences::GetInstanceForService() can be called from GetService(), and + // RegisterStrongMemoryReporter calls GetService(nsIMemoryReporter). To + // avoid a potential recursive GetService() call, we can't register the + // memory reporter here; instead, do it off a runnable. + RefPtr<AddPreferencesMemoryReporterRunnable> runnable = + new AddPreferencesMemoryReporterRunnable(); + NS_DispatchToMainThread(runnable); + + return do_AddRef(sPreferences); +} + +/* static */ +bool Preferences::IsServiceAvailable() { return !!sPreferences; } + +/* static */ +bool Preferences::InitStaticMembers() { + MOZ_ASSERT(NS_IsMainThread() || ServoStyleSet::IsInServoTraversal()); + + if (MOZ_LIKELY(sPreferences)) { + return true; + } + + if (!sShutdown) { + MOZ_ASSERT(NS_IsMainThread()); + nsCOMPtr<nsIPrefService> prefService = + do_GetService(NS_PREFSERVICE_CONTRACTID); + } + + return sPreferences != nullptr; +} + +/* static */ +void Preferences::Shutdown() { + if (!sShutdown) { + sShutdown = true; // Don't create the singleton instance after here. + sPreferences = nullptr; + } +} + +Preferences::Preferences() + : mRootBranch(new nsPrefBranch("", PrefValueKind::User)), + mDefaultRootBranch(new nsPrefBranch("", PrefValueKind::Default)) {} + +Preferences::~Preferences() { + MOZ_ASSERT(!sPreferences); + + MOZ_ASSERT(!gCallbacksInProgress); + + CallbackNode* node = gFirstCallback; + while (node) { + CallbackNode* next_node = node->Next(); + delete node; + node = next_node; + } + gLastPriorityNode = gFirstCallback = nullptr; + + delete HashTable(); + HashTable() = nullptr; + +#ifdef DEBUG + delete gOnceStaticPrefsAntiFootgun; + gOnceStaticPrefsAntiFootgun = nullptr; +#endif + +#ifdef ACCESS_COUNTS + delete gAccessCounts; +#endif + + gSharedMap = nullptr; + + PrefNameArena().Clear(); +} + +NS_IMPL_ISUPPORTS(Preferences, nsIPrefService, nsIObserver, nsIPrefBranch, + nsISupportsWeakReference) + +/* static */ +void Preferences::SerializePreferences(nsCString& aStr) { + MOZ_RELEASE_ASSERT(InitStaticMembers()); + + aStr.Truncate(); + + for (auto iter = HashTable()->iter(); !iter.done(); iter.next()) { + Pref* pref = iter.get().get(); + if (!pref->IsTypeNone() && pref->HasAdvisablySizedValues()) { + pref->SerializeAndAppend(aStr); + } + } + + aStr.Append('\0'); +} + +/* static */ +void Preferences::DeserializePreferences(char* aStr, size_t aPrefsLen) { + MOZ_ASSERT(!XRE_IsParentProcess()); + + MOZ_ASSERT(!gChangedDomPrefs); + gChangedDomPrefs = new nsTArray<dom::Pref>(); + + char* p = aStr; + while (*p != '\0') { + dom::Pref pref; + p = Pref::Deserialize(p, &pref); + gChangedDomPrefs->AppendElement(pref); + } + + // We finished parsing on a '\0'. That should be the last char in the shared + // memory. (aPrefsLen includes the '\0'.) + MOZ_ASSERT(p == aStr + aPrefsLen - 1); + +#ifdef DEBUG + MOZ_ASSERT(!gContentProcessPrefsAreInited); + gContentProcessPrefsAreInited = true; +#endif +} + +// Forward declarations. +namespace StaticPrefs { + +static void InitAll(); +static void StartObservingAlwaysPrefs(); +static void InitOncePrefs(); +static void InitStaticPrefsFromShared(); +static void RegisterOncePrefs(SharedPrefMapBuilder& aBuilder); + +} // namespace StaticPrefs + +/* static */ +FileDescriptor Preferences::EnsureSnapshot(size_t* aSize) { + MOZ_ASSERT(XRE_IsParentProcess()); + + if (!gSharedMap) { + SharedPrefMapBuilder builder; + + for (auto iter = HashTable()->iter(); !iter.done(); iter.next()) { + iter.get()->AddToMap(builder); + } + + // Store the current value of `once`-mirrored prefs. After this point they + // will be immutable. + StaticPrefs::RegisterOncePrefs(builder); + + gSharedMap = new SharedPrefMap(std::move(builder)); + + // Once we've built a snapshot of the database, there's no need to continue + // storing dynamic copies of the preferences it contains. Once we reset the + // hashtable, preference lookups will fall back to the snapshot for any + // preferences not in the dynamic hashtable. + // + // And since the majority of the database is now contained in the snapshot, + // we can initialize the hashtable with the expected number of per-session + // changed preferences, rather than the expected total number of + // preferences. + HashTable()->clearAndCompact(); + Unused << HashTable()->reserve(kHashTableInitialLengthContent); + + PrefNameArena().Clear(); + gCallbackPref = nullptr; + } + + *aSize = gSharedMap->MapSize(); + return gSharedMap->CloneFileDescriptor(); +} + +/* static */ +void Preferences::InitSnapshot(const FileDescriptor& aHandle, size_t aSize) { + MOZ_ASSERT(!XRE_IsParentProcess()); + MOZ_ASSERT(!gSharedMap); + + gSharedMap = new SharedPrefMap(aHandle, aSize); + + StaticPrefs::InitStaticPrefsFromShared(); +} + +/* static */ +void Preferences::InitializeUserPrefs() { + MOZ_ASSERT(XRE_IsParentProcess()); + MOZ_ASSERT(!sPreferences->mCurrentFile, "Should only initialize prefs once"); + + // Prefs which are set before we initialize the profile are silently + // discarded. This is stupid, but there are various tests which depend on + // this behavior. + sPreferences->ResetUserPrefs(); + + nsCOMPtr<nsIFile> prefsFile = sPreferences->ReadSavedPrefs(); + sPreferences->ReadUserOverridePrefs(); + + sPreferences->mDirty = false; + + // Don't set mCurrentFile until we're done so that dirty flags work properly. + sPreferences->mCurrentFile = std::move(prefsFile); +} + +/* static */ +void Preferences::FinishInitializingUserPrefs() { + sPreferences->NotifyServiceObservers(NS_PREFSERVICE_READ_TOPIC_ID); +} + +NS_IMETHODIMP +Preferences::Observe(nsISupports* aSubject, const char* aTopic, + const char16_t* someData) { + if (MOZ_UNLIKELY(!XRE_IsParentProcess())) { + return NS_ERROR_NOT_AVAILABLE; + } + + nsresult rv = NS_OK; + + if (!nsCRT::strcmp(aTopic, "profile-before-change")) { + // Normally prefs aren't written after this point, and so we kick off + // an asynchronous pref save so that I/O can be done in parallel with + // other shutdown. + if (AllowOffMainThreadSave()) { + SavePrefFile(nullptr); + } + + } else if (!nsCRT::strcmp(aTopic, "profile-before-change-telemetry")) { + // It's possible that a profile-before-change observer after ours + // set a pref. A blocking save here re-saves if necessary and also waits + // for any pending saves to complete. + SavePrefFileBlocking(); + MOZ_ASSERT(!mDirty, "Preferences should not be dirty"); + mProfileShutdown = true; + + } else if (!nsCRT::strcmp(aTopic, "reload-default-prefs")) { + // Reload the default prefs from file. + Unused << InitInitialObjects(/* isStartup */ false); + + } else if (!nsCRT::strcmp(aTopic, "suspend_process_notification")) { + // Our process is being suspended. The OS may wake our process later, + // or it may kill the process. In case our process is going to be killed + // from the suspended state, we save preferences before suspending. + rv = SavePrefFileBlocking(); + } + + return rv; +} + +NS_IMETHODIMP +Preferences::ReadDefaultPrefsFromFile(nsIFile* aFile) { + ENSURE_PARENT_PROCESS("Preferences::ReadDefaultPrefsFromFile", "all prefs"); + + if (!aFile) { + NS_ERROR("ReadDefaultPrefsFromFile requires a parameter"); + return NS_ERROR_INVALID_ARG; + } + + return openPrefFile(aFile, PrefValueKind::Default); +} + +NS_IMETHODIMP +Preferences::ReadUserPrefsFromFile(nsIFile* aFile) { + ENSURE_PARENT_PROCESS("Preferences::ReadUserPrefsFromFile", "all prefs"); + + if (!aFile) { + NS_ERROR("ReadUserPrefsFromFile requires a parameter"); + return NS_ERROR_INVALID_ARG; + } + + return openPrefFile(aFile, PrefValueKind::User); +} + +NS_IMETHODIMP +Preferences::ResetPrefs() { + ENSURE_PARENT_PROCESS("Preferences::ResetPrefs", "all prefs"); + + if (gSharedMap) { + return NS_ERROR_NOT_AVAILABLE; + } + + HashTable()->clearAndCompact(); + Unused << HashTable()->reserve(kHashTableInitialLengthParent); + + PrefNameArena().Clear(); + + return InitInitialObjects(/* isStartup */ false); +} + +NS_IMETHODIMP +Preferences::ResetUserPrefs() { + ENSURE_PARENT_PROCESS("Preferences::ResetUserPrefs", "all prefs"); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + MOZ_ASSERT(NS_IsMainThread()); + + Vector<const char*> prefNames; + for (auto iter = HashTable()->modIter(); !iter.done(); iter.next()) { + Pref* pref = iter.get().get(); + + if (pref->HasUserValue()) { + if (!prefNames.append(pref->Name())) { + return NS_ERROR_OUT_OF_MEMORY; + } + + pref->ClearUserValue(); + if (!pref->HasDefaultValue()) { + iter.remove(); + } + } + } + + for (const char* prefName : prefNames) { + NotifyCallbacks(nsDependentCString(prefName)); + } + + Preferences::HandleDirty(); + return NS_OK; +} + +bool Preferences::AllowOffMainThreadSave() { + // Put in a preference that allows us to disable off main thread preference + // file save. + if (sAllowOMTPrefWrite < 0) { + bool value = false; + Preferences::GetBool("preferences.allow.omt-write", &value); + sAllowOMTPrefWrite = value ? 1 : 0; + } + + return !!sAllowOMTPrefWrite; +} + +nsresult Preferences::SavePrefFileBlocking() { + if (mDirty) { + return SavePrefFileInternal(nullptr, SaveMethod::Blocking); + } + + // If we weren't dirty to start, SavePrefFileInternal will early exit so + // there is no guarantee that we don't have oustanding async saves in the + // pipe. Since the contract of SavePrefFileOnMainThread is that the file on + // disk matches the preferences, we have to make sure those requests are + // completed. + + if (AllowOffMainThreadSave()) { + PreferencesWriter::Flush(); + } + + return NS_OK; +} + +nsresult Preferences::SavePrefFileAsynchronous() { + return SavePrefFileInternal(nullptr, SaveMethod::Asynchronous); +} + +NS_IMETHODIMP +Preferences::SavePrefFile(nsIFile* aFile) { + // This is the method accessible from service API. Make it off main thread. + return SavePrefFileInternal(aFile, SaveMethod::Asynchronous); +} + +/* static */ +void Preferences::SetPreference(const dom::Pref& aDomPref) { + MOZ_ASSERT(!XRE_IsParentProcess()); + NS_ENSURE_TRUE(InitStaticMembers(), (void)0); + + const nsCString& prefName = aDomPref.name(); + + Pref* pref; + auto p = HashTable()->lookupForAdd(prefName.get()); + if (!p) { + pref = new Pref(prefName); + if (!HashTable()->add(p, pref)) { + delete pref; + return; + } + } else { + pref = p->get(); + } + + bool valueChanged = false; + pref->FromDomPref(aDomPref, &valueChanged); + + // When the parent process clears a pref's user value we get a DomPref here + // with no default value and no user value. There are two possibilities. + // + // - There was an existing pref with only a user value. FromDomPref() will + // have just cleared that user value, so the pref can be removed. + // + // - There was no existing pref. FromDomPref() will have done nothing, and + // `pref` will be valueless. We will end up adding and removing the value + // needlessly, but that's ok because this case is rare. + // + if (!pref->HasDefaultValue() && !pref->HasUserValue()) { + // If the preference exists in the shared map, we need to keep the dynamic + // entry around to mask it. + if (gSharedMap->Has(pref->Name())) { + pref->SetType(PrefType::None); + } else { + HashTable()->remove(prefName.get()); + } + pref = nullptr; + } + + // Note: we don't have to worry about HandleDirty() because we are setting + // prefs in the content process that have come from the parent process. + + if (valueChanged) { + if (pref) { + NotifyCallbacks(prefName, PrefWrapper(pref)); + } else { + NotifyCallbacks(prefName); + } + } +} + +/* static */ +void Preferences::GetPreference(dom::Pref* aDomPref) { + MOZ_ASSERT(XRE_IsParentProcess()); + + Pref* pref = pref_HashTableLookup(aDomPref->name().get()); + if (pref && pref->HasAdvisablySizedValues()) { + pref->ToDomPref(aDomPref); + } +} + +#ifdef DEBUG +bool Preferences::ArePrefsInitedInContentProcess() { + MOZ_ASSERT(!XRE_IsParentProcess()); + return gContentProcessPrefsAreInited; +} +#endif + +NS_IMETHODIMP +Preferences::GetBranch(const char* aPrefRoot, nsIPrefBranch** aRetVal) { + if ((nullptr != aPrefRoot) && (*aPrefRoot != '\0')) { + // TODO: Cache this stuff and allow consumers to share branches (hold weak + // references, I think). + RefPtr<nsPrefBranch> prefBranch = + new nsPrefBranch(aPrefRoot, PrefValueKind::User); + prefBranch.forget(aRetVal); + } else { + // Special case: caching the default root. + nsCOMPtr<nsIPrefBranch> root(sPreferences->mRootBranch); + root.forget(aRetVal); + } + + return NS_OK; +} + +NS_IMETHODIMP +Preferences::GetDefaultBranch(const char* aPrefRoot, nsIPrefBranch** aRetVal) { + if (!aPrefRoot || !aPrefRoot[0]) { + nsCOMPtr<nsIPrefBranch> root(sPreferences->mDefaultRootBranch); + root.forget(aRetVal); + return NS_OK; + } + + // TODO: Cache this stuff and allow consumers to share branches (hold weak + // references, I think). + RefPtr<nsPrefBranch> prefBranch = + new nsPrefBranch(aPrefRoot, PrefValueKind::Default); + if (!prefBranch) { + return NS_ERROR_OUT_OF_MEMORY; + } + + prefBranch.forget(aRetVal); + return NS_OK; +} + +NS_IMETHODIMP +Preferences::ReadStats(nsIPrefStatsCallback* aCallback) { +#ifdef ACCESS_COUNTS + for (auto iter = gAccessCounts->Iter(); !iter.Done(); iter.Next()) { + aCallback->Visit(iter.Key(), iter.Data()); + } + + return NS_OK; +#else + return NS_ERROR_NOT_IMPLEMENTED; +#endif +} + +NS_IMETHODIMP +Preferences::ResetStats() { +#ifdef ACCESS_COUNTS + gAccessCounts->Clear(); + return NS_OK; +#else + return NS_ERROR_NOT_IMPLEMENTED; +#endif +} + +NS_IMETHODIMP +Preferences::GetDirty(bool* aRetVal) { + *aRetVal = mDirty; + return NS_OK; +} + +nsresult Preferences::NotifyServiceObservers(const char* aTopic) { + nsCOMPtr<nsIObserverService> observerService = services::GetObserverService(); + if (!observerService) { + return NS_ERROR_FAILURE; + } + + auto subject = static_cast<nsIPrefService*>(this); + observerService->NotifyObservers(subject, aTopic, nullptr); + + return NS_OK; +} + +already_AddRefed<nsIFile> Preferences::ReadSavedPrefs() { + nsCOMPtr<nsIFile> file; + nsresult rv = + NS_GetSpecialDirectory(NS_APP_PREFS_50_FILE, getter_AddRefs(file)); + if (NS_WARN_IF(NS_FAILED(rv))) { + return nullptr; + } + + rv = openPrefFile(file, PrefValueKind::User); + if (rv == NS_ERROR_FILE_NOT_FOUND) { + // This is a normal case for new users. + Telemetry::ScalarSet( + Telemetry::ScalarID::PREFERENCES_CREATED_NEW_USER_PREFS_FILE, true); + rv = NS_OK; + } else if (NS_FAILED(rv)) { + // Save a backup copy of the current (invalid) prefs file, since all prefs + // from the error line to the end of the file will be lost (bug 361102). + // TODO we should notify the user about it (bug 523725). + Telemetry::ScalarSet( + Telemetry::ScalarID::PREFERENCES_PREFS_FILE_WAS_INVALID, true); + MakeBackupPrefFile(file); + } + + return file.forget(); +} + +void Preferences::ReadUserOverridePrefs() { + nsCOMPtr<nsIFile> aFile; + nsresult rv = + NS_GetSpecialDirectory(NS_APP_PREFS_50_DIR, getter_AddRefs(aFile)); + if (NS_WARN_IF(NS_FAILED(rv))) { + return; + } + + aFile->AppendNative("user.js"_ns); + rv = openPrefFile(aFile, PrefValueKind::User); + if (rv != NS_ERROR_FILE_NOT_FOUND) { + // If the file exists and was at least partially read, record that in + // telemetry as it may be a sign of pref injection. + Telemetry::ScalarSet(Telemetry::ScalarID::PREFERENCES_READ_USER_JS, true); + } +} + +nsresult Preferences::MakeBackupPrefFile(nsIFile* aFile) { + // Example: this copies "prefs.js" to "Invalidprefs.js" in the same directory. + // "Invalidprefs.js" is removed if it exists, prior to making the copy. + nsAutoString newFilename; + nsresult rv = aFile->GetLeafName(newFilename); + NS_ENSURE_SUCCESS(rv, rv); + + newFilename.InsertLiteral(u"Invalid", 0); + nsCOMPtr<nsIFile> newFile; + rv = aFile->GetParent(getter_AddRefs(newFile)); + NS_ENSURE_SUCCESS(rv, rv); + + rv = newFile->Append(newFilename); + NS_ENSURE_SUCCESS(rv, rv); + + bool exists = false; + newFile->Exists(&exists); + if (exists) { + rv = newFile->Remove(false); + NS_ENSURE_SUCCESS(rv, rv); + } + + rv = aFile->CopyTo(nullptr, newFilename); + NS_ENSURE_SUCCESS(rv, rv); + + return rv; +} + +nsresult Preferences::SavePrefFileInternal(nsIFile* aFile, + SaveMethod aSaveMethod) { + ENSURE_PARENT_PROCESS("Preferences::SavePrefFileInternal", "all prefs"); + + // We allow different behavior here when aFile argument is not null, but it + // happens to be the same as the current file. It is not clear that we + // should, but it does give us a "force" save on the unmodified pref file + // (see the original bug 160377 when we added this.) + + if (nullptr == aFile) { + mSavePending = false; + + // Off main thread writing only if allowed. + if (!AllowOffMainThreadSave()) { + aSaveMethod = SaveMethod::Blocking; + } + + // The mDirty flag tells us if we should write to mCurrentFile. We only + // check this flag when the caller wants to write to the default. + if (!mDirty) { + return NS_OK; + } + + // Check for profile shutdown after mDirty because the runnables from + // HandleDirty() can still be pending. + if (mProfileShutdown) { + NS_WARNING("Cannot save pref file after profile shutdown."); + return NS_ERROR_ILLEGAL_DURING_SHUTDOWN; + } + + // It's possible that we never got a prefs file. + nsresult rv = NS_OK; + if (mCurrentFile) { + rv = WritePrefFile(mCurrentFile, aSaveMethod); + } + + // If we succeeded writing to mCurrentFile, reset the dirty flag. + if (NS_SUCCEEDED(rv)) { + mDirty = false; + } + return rv; + + } else { + // We only allow off main thread writes on mCurrentFile. + return WritePrefFile(aFile, SaveMethod::Blocking); + } +} + +nsresult Preferences::WritePrefFile(nsIFile* aFile, SaveMethod aSaveMethod) { + MOZ_ASSERT(XRE_IsParentProcess()); + + if (!HashTable()) { + return NS_ERROR_NOT_INITIALIZED; + } + + AUTO_PROFILER_LABEL("Preferences::WritePrefFile", OTHER); + + if (AllowOffMainThreadSave()) { + nsresult rv = NS_OK; + UniquePtr<PrefSaveData> prefs = MakeUnique<PrefSaveData>(pref_savePrefs()); + + // Put the newly constructed preference data into sPendingWriteData + // for the next request to pick up + prefs.reset(PreferencesWriter::sPendingWriteData.exchange(prefs.release())); + if (prefs) { + // There was a previous request that hasn't been processed, + // and this is the data it had. + return rv; + } + + // There were no previous requests. Dispatch one since sPendingWriteData has + // the up to date information. + nsCOMPtr<nsIEventTarget> target = + do_GetService(NS_STREAMTRANSPORTSERVICE_CONTRACTID, &rv); + if (NS_SUCCEEDED(rv)) { + bool async = aSaveMethod == SaveMethod::Asynchronous; + + // Increment sPendingWriteCount, even though it's redundant to track this + // in the case of a sync runnable; it just makes it easier to simply + // decrement this inside PWRunnable. We could alternatively increment + // sPendingWriteCount in PWRunnable's constructor, but if for any reason + // in future code we create a PWRunnable without dispatching it, we would + // get stuck in an infinite SpinEventLoopUntil inside + // PreferencesWriter::Flush. Better that in future code we miss an + // increment of sPendingWriteCount and cause a simple crash due to it + // ending up negative. + PreferencesWriter::sPendingWriteCount++; + if (async) { + rv = target->Dispatch(new PWRunnable(aFile), + nsIEventTarget::DISPATCH_NORMAL); + } else { + // Note that we don't get the nsresult return value here. + SyncRunnable::DispatchToThread(target, new PWRunnable(aFile), true); + } + return rv; + } + + // If we can't get the thread for writing, for whatever reason, do the main + // thread write after making some noise. + MOZ_ASSERT(false, "failed to get the target thread for OMT pref write"); + } + + // This will do a main thread write. It is safe to do it this way because + // AllowOffMainThreadSave() returns a consistent value for the lifetime of + // the parent process. + PrefSaveData prefsData = pref_savePrefs(); + return PreferencesWriter::Write(aFile, prefsData); +} + +static nsresult openPrefFile(nsIFile* aFile, PrefValueKind aKind) { + MOZ_ASSERT(XRE_IsParentProcess()); + + nsCString data; + MOZ_TRY_VAR(data, URLPreloader::ReadFile(aFile)); + + nsAutoString filenameUtf16; + aFile->GetLeafName(filenameUtf16); + NS_ConvertUTF16toUTF8 filename(filenameUtf16); + + nsAutoString path; + aFile->GetPath(path); + + Parser parser; + if (!parser.Parse(aKind, NS_ConvertUTF16toUTF8(path).get(), data)) { + return NS_ERROR_FILE_CORRUPTED; + } + + return NS_OK; +} + +static nsresult parsePrefData(const nsCString& aData, PrefValueKind aKind) { + const nsCString path = "$MOZ_DEFAULT_PREFS"_ns; + + Parser parser; + if (!parser.Parse(aKind, path.get(), aData)) { + return NS_ERROR_FILE_CORRUPTED; + } + + return NS_OK; +} + +static int pref_CompareFileNames(nsIFile* aFile1, nsIFile* aFile2, + void* /* unused */) { + nsAutoCString filename1, filename2; + aFile1->GetNativeLeafName(filename1); + aFile2->GetNativeLeafName(filename2); + + return Compare(filename2, filename1); +} + +// Load default pref files from a directory. The files in the directory are +// sorted reverse-alphabetically; a set of "special file names" may be +// specified which are loaded after all the others. +static nsresult pref_LoadPrefsInDir(nsIFile* aDir, + char const* const* aSpecialFiles, + uint32_t aSpecialFilesCount) { + MOZ_ASSERT(XRE_IsParentProcess()); + + nsresult rv, rv2; + + nsCOMPtr<nsIDirectoryEnumerator> dirIterator; + + // This may fail in some normal cases, such as embedders who do not use a + // GRE. + rv = aDir->GetDirectoryEntries(getter_AddRefs(dirIterator)); + if (NS_FAILED(rv)) { + // If the directory doesn't exist, then we have no reason to complain. We + // loaded everything (and nothing) successfully. + if (rv == NS_ERROR_FILE_NOT_FOUND || + rv == NS_ERROR_FILE_TARGET_DOES_NOT_EXIST) { + rv = NS_OK; + } + return rv; + } + + nsCOMArray<nsIFile> prefFiles(INITIAL_PREF_FILES); + nsCOMArray<nsIFile> specialFiles(aSpecialFilesCount); + nsCOMPtr<nsIFile> prefFile; + + while (NS_SUCCEEDED(dirIterator->GetNextFile(getter_AddRefs(prefFile))) && + prefFile) { + nsAutoCString leafName; + prefFile->GetNativeLeafName(leafName); + MOZ_ASSERT( + !leafName.IsEmpty(), + "Failure in default prefs: directory enumerator returned empty file?"); + + // Skip non-js files. + if (StringEndsWith(leafName, ".js"_ns, + nsCaseInsensitiveCStringComparator)) { + bool shouldParse = true; + + // Separate out special files. + for (uint32_t i = 0; i < aSpecialFilesCount; ++i) { + if (leafName.Equals(nsDependentCString(aSpecialFiles[i]))) { + shouldParse = false; + // Special files should be processed in order. We put them into the + // array by index, which can make the array sparse. + specialFiles.ReplaceObjectAt(prefFile, i); + } + } + + if (shouldParse) { + prefFiles.AppendObject(prefFile); + } + } + } + + if (prefFiles.Count() + specialFiles.Count() == 0) { + NS_WARNING("No default pref files found."); + if (NS_SUCCEEDED(rv)) { + rv = NS_SUCCESS_FILE_DIRECTORY_EMPTY; + } + return rv; + } + + prefFiles.Sort(pref_CompareFileNames, nullptr); + + uint32_t arrayCount = prefFiles.Count(); + uint32_t i; + for (i = 0; i < arrayCount; ++i) { + rv2 = openPrefFile(prefFiles[i], PrefValueKind::Default); + if (NS_FAILED(rv2)) { + NS_ERROR("Default pref file not parsed successfully."); + rv = rv2; + } + } + + arrayCount = specialFiles.Count(); + for (i = 0; i < arrayCount; ++i) { + // This may be a sparse array; test before parsing. + nsIFile* file = specialFiles[i]; + if (file) { + rv2 = openPrefFile(file, PrefValueKind::Default); + if (NS_FAILED(rv2)) { + NS_ERROR("Special default pref file not parsed successfully."); + rv = rv2; + } + } + } + + return rv; +} + +static nsresult pref_ReadPrefFromJar(nsZipArchive* aJarReader, + const char* aName) { + nsCString manifest; + MOZ_TRY_VAR(manifest, + URLPreloader::ReadZip(aJarReader, nsDependentCString(aName))); + + Parser parser; + if (!parser.Parse(PrefValueKind::Default, aName, manifest)) { + return NS_ERROR_FILE_CORRUPTED; + } + + return NS_OK; +} + +static nsresult pref_ReadDefaultPrefs(const RefPtr<nsZipArchive> jarReader, + const char* path) { + UniquePtr<nsZipFind> find; + nsTArray<nsCString> prefEntries; + const char* entryName; + uint16_t entryNameLen; + + nsresult rv = jarReader->FindInit(path, getter_Transfers(find)); + NS_ENSURE_SUCCESS(rv, rv); + + while (NS_SUCCEEDED(find->FindNext(&entryName, &entryNameLen))) { + prefEntries.AppendElement(Substring(entryName, entryNameLen)); + } + + prefEntries.Sort(); + for (uint32_t i = prefEntries.Length(); i--;) { + rv = pref_ReadPrefFromJar(jarReader, prefEntries[i].get()); + if (NS_FAILED(rv)) { + NS_WARNING("Error parsing preferences."); + } + } + + return NS_OK; +} + +#ifdef MOZ_GECKO_PROFILER +static nsCString PrefValueToString(const bool* b) { + return nsCString(*b ? "true" : "false"); +} +static nsCString PrefValueToString(const int* i) { + return nsPrintfCString("%d", *i); +} +static nsCString PrefValueToString(const uint32_t* u) { + return nsPrintfCString("%d", *u); +} +static nsCString PrefValueToString(const float* f) { + return nsPrintfCString("%f", *f); +} +static nsCString PrefValueToString(const nsACString& s) { return nsCString(s); } +#endif + +// These preference getter wrappers allow us to look up the value for static +// preferences based on their native types, rather than manually mapping them to +// the appropriate Preferences::Get* functions. +// We define these methods in a struct which is made friend of Preferences in +// order to access private members. +struct Internals { +#ifdef MOZ_GECKO_PROFILER + struct PreferenceReadMarker { + static constexpr Span<const char> MarkerTypeName() { + return MakeStringSpan("PreferenceRead"); + } + static void StreamJSONMarkerData( + baseprofiler::SpliceableJSONWriter& aWriter, + const ProfilerString8View& aPrefName, + const Maybe<PrefValueKind>& aPrefKind, PrefType aPrefType, + const ProfilerString8View& aPrefValue) { + aWriter.StringProperty("prefName", aPrefName); + aWriter.StringProperty("prefKind", PrefValueKindToString(aPrefKind)); + aWriter.StringProperty("prefType", PrefTypeToString(aPrefType)); + aWriter.StringProperty("prefValue", aPrefValue); + } + static MarkerSchema MarkerTypeDisplay() { + using MS = MarkerSchema; + MS schema{MS::Location::markerChart, MS::Location::markerTable}; + schema.AddKeyLabelFormat("prefName", "Name", MS::Format::string); + schema.AddKeyLabelFormat("prefKind", "Kind", MS::Format::string); + schema.AddKeyLabelFormat("prefType", "Type", MS::Format::string); + schema.AddKeyLabelFormat("prefValue", "Value", MS::Format::string); + return schema; + } + + private: + static Span<const char> PrefValueKindToString( + const Maybe<PrefValueKind>& aKind) { + if (aKind) { + return *aKind == PrefValueKind::Default ? MakeStringSpan("Default") + : MakeStringSpan("User"); + } + return "Shared"; + } + + static Span<const char> PrefTypeToString(PrefType type) { + switch (type) { + case PrefType::None: + return "None"; + case PrefType::Int: + return "Int"; + case PrefType::Bool: + return "Bool"; + case PrefType::String: + return "String"; + default: + MOZ_ASSERT_UNREACHABLE("Unknown preference type."); + return "Unknown"; + } + } + }; +#endif // MOZ_GECKO_PROFILER + + template <typename T> + static nsresult GetPrefValue(const char* aPrefName, T&& aResult, + PrefValueKind aKind) { + nsresult rv = NS_ERROR_UNEXPECTED; + NS_ENSURE_TRUE(Preferences::InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + if (Maybe<PrefWrapper> pref = pref_Lookup(aPrefName)) { + rv = pref->GetValue(aKind, std::forward<T>(aResult)); + +#ifdef MOZ_GECKO_PROFILER + if (profiler_feature_active(ProfilerFeature::PreferenceReads)) { + profiler_add_marker( + "PreferenceRead", baseprofiler::category::OTHER_PreferenceRead, {}, + PreferenceReadMarker{}, + ProfilerString8View::WrapNullTerminatedString(aPrefName), + Some(aKind), pref->Type(), PrefValueToString(aResult)); + } +#endif + } + + return rv; + } + + template <typename T> + static nsresult GetSharedPrefValue(const char* aName, T* aResult) { + nsresult rv = NS_ERROR_UNEXPECTED; + + if (Maybe<PrefWrapper> pref = pref_SharedLookup(aName)) { + rv = pref->GetValue(PrefValueKind::User, aResult); + +#ifdef MOZ_GECKO_PROFILER + if (profiler_feature_active(ProfilerFeature::PreferenceReads)) { + profiler_add_marker( + "PreferenceRead", baseprofiler::category::OTHER_PreferenceRead, {}, + PreferenceReadMarker{}, + ProfilerString8View::WrapNullTerminatedString(aName), + Nothing() /* indicates Shared */, pref->Type(), + PrefValueToString(aResult)); + } +#endif + } + + return rv; + } + + template <typename T> + static T GetPref(const char* aPrefName, T aFallback, + PrefValueKind aKind = PrefValueKind::User) { + T result = aFallback; + GetPrefValue(aPrefName, &result, aKind); + return result; + } + + template <typename T> + static void UpdateMirror(const char* aPref, void* aMirror) { + StripAtomic<T> value; + + nsresult rv = GetPrefValue(aPref, &value, PrefValueKind::User); + if (NS_SUCCEEDED(rv)) { + *static_cast<T*>(aMirror) = value; + } else { + // GetPrefValue() can fail if the update is caused by the pref being + // deleted or if it fails to make a cast. This assertion is the only place + // where we safeguard these. In this case the mirror variable will be + // untouched, thus keeping the value it had prior to the change. + // (Note that this case won't happen for a deletion via DeleteBranch() + // unless bug 343600 is fixed, but it will happen for a deletion via + // ClearUserPref().) + NS_WARNING(nsPrintfCString("Pref changed failure: %s\n", aPref).get()); + MOZ_ASSERT(false); + } + } + + template <typename T> + static nsresult RegisterCallback(void* aMirror, const nsACString& aPref) { + return Preferences::RegisterCallback(UpdateMirror<T>, aPref, aMirror, + Preferences::ExactMatch, + /* isPriority */ true); + } +}; + +// Initialize default preference JavaScript buffers from appropriate TEXT +// resources. +/* static */ +nsresult Preferences::InitInitialObjects(bool aIsStartup) { + MOZ_ASSERT(NS_IsMainThread()); + + if (!XRE_IsParentProcess()) { + MOZ_DIAGNOSTIC_ASSERT(gSharedMap); + if (aIsStartup) { + StaticPrefs::StartObservingAlwaysPrefs(); + } + return NS_OK; + } + + // Initialize static prefs before prefs from data files so that the latter + // will override the former. + StaticPrefs::InitAll(); + + // In the omni.jar case, we load the following prefs: + // - jar:$gre/omni.jar!/greprefs.js + // - jar:$gre/omni.jar!/defaults/pref/*.js + // + // In the non-omni.jar case, we load: + // - $gre/greprefs.js + // + // In both cases, we also load: + // - $gre/defaults/pref/*.js + // + // This is kept for bug 591866 (channel-prefs.js should not be in omni.jar) + // in the `$app == $gre` case; we load all files instead of channel-prefs.js + // only to have the same behaviour as `$app != $gre`, where this is required + // as a supported location for GRE preferences. + // + // When `$app != $gre`, we additionally load, in the omni.jar case: + // - jar:$app/omni.jar!/defaults/preferences/*.js + // - $app/defaults/preferences/*.js + // + // and in the non-omni.jar case: + // - $app/defaults/preferences/*.js + // + // When `$app == $gre`, we additionally load, in the omni.jar case: + // - jar:$gre/omni.jar!/defaults/preferences/*.js + // + // Thus, in the omni.jar case, we always load app-specific default + // preferences from omni.jar, whether or not `$app == $gre`. + + nsresult rv = NS_ERROR_FAILURE; + UniquePtr<nsZipFind> find; + nsTArray<nsCString> prefEntries; + const char* entryName; + uint16_t entryNameLen; + + RefPtr<nsZipArchive> jarReader = Omnijar::GetReader(Omnijar::GRE); + if (jarReader) { +#ifdef MOZ_WIDGET_ANDROID + // Try to load an architecture-specific greprefs.js first. This will be + // present in FAT AAR builds of GeckoView on Android. + const char* abi = getenv("MOZ_ANDROID_CPU_ABI"); + if (abi) { + nsAutoCString path; + path.AppendPrintf("%s/greprefs.js", abi); + rv = pref_ReadPrefFromJar(jarReader, path.get()); + } + + if (NS_FAILED(rv)) { + // Fallback to toplevel greprefs.js if arch-specific load fails. + rv = pref_ReadPrefFromJar(jarReader, "greprefs.js"); + } +#else + // Load jar:$gre/omni.jar!/greprefs.js. + rv = pref_ReadPrefFromJar(jarReader, "greprefs.js"); +#endif + NS_ENSURE_SUCCESS(rv, rv); + + // Load jar:$gre/omni.jar!/defaults/pref/*.js. + rv = pref_ReadDefaultPrefs(jarReader, "defaults/pref/*.js$"); + NS_ENSURE_SUCCESS(rv, rv); + +#ifdef MOZ_WIDGET_ANDROID + // Load jar:$gre/omni.jar!/defaults/pref/$MOZ_ANDROID_CPU_ABI/*.js. + nsAutoCString path; + path.AppendPrintf("jar:$gre/omni.jar!/defaults/pref/%s/*.js$", abi); + pref_ReadDefaultPrefs(jarReader, path.get()); + NS_ENSURE_SUCCESS(rv, rv); +#endif + } else { + // Load $gre/greprefs.js. + nsCOMPtr<nsIFile> greprefsFile; + rv = NS_GetSpecialDirectory(NS_GRE_DIR, getter_AddRefs(greprefsFile)); + NS_ENSURE_SUCCESS(rv, rv); + + rv = greprefsFile->AppendNative("greprefs.js"_ns); + NS_ENSURE_SUCCESS(rv, rv); + + rv = openPrefFile(greprefsFile, PrefValueKind::Default); + if (NS_FAILED(rv)) { + NS_WARNING( + "Error parsing GRE default preferences. Is this an old-style " + "embedding app?"); + } + } + + // Load $gre/defaults/pref/*.js. + nsCOMPtr<nsIFile> defaultPrefDir; + rv = NS_GetSpecialDirectory(NS_APP_PREF_DEFAULTS_50_DIR, + getter_AddRefs(defaultPrefDir)); + NS_ENSURE_SUCCESS(rv, rv); + + // These pref file names should not be used: we process them after all other + // application pref files for backwards compatibility. + static const char* specialFiles[] = { +#if defined(XP_MACOSX) + "macprefs.js" +#elif defined(XP_WIN) + "winpref.js" +#elif defined(XP_UNIX) + "unix.js" +# if defined(_AIX) + , + "aix.js" +# endif +#elif defined(XP_BEOS) + "beos.js" +#endif + }; + + rv = pref_LoadPrefsInDir(defaultPrefDir, specialFiles, + ArrayLength(specialFiles)); + if (NS_FAILED(rv)) { + NS_WARNING("Error parsing application default preferences."); + } + + // Load jar:$app/omni.jar!/defaults/preferences/*.js + // or jar:$gre/omni.jar!/defaults/preferences/*.js. + RefPtr<nsZipArchive> appJarReader = Omnijar::GetReader(Omnijar::APP); + + // GetReader(Omnijar::APP) returns null when `$app == $gre`, in + // which case we look for app-specific default preferences in $gre. + if (!appJarReader) { + appJarReader = Omnijar::GetReader(Omnijar::GRE); + } + + if (appJarReader) { + rv = appJarReader->FindInit("defaults/preferences/*.js$", + getter_Transfers(find)); + NS_ENSURE_SUCCESS(rv, rv); + prefEntries.Clear(); + while (NS_SUCCEEDED(find->FindNext(&entryName, &entryNameLen))) { + prefEntries.AppendElement(Substring(entryName, entryNameLen)); + } + prefEntries.Sort(); + for (uint32_t i = prefEntries.Length(); i--;) { + rv = pref_ReadPrefFromJar(appJarReader, prefEntries[i].get()); + if (NS_FAILED(rv)) { + NS_WARNING("Error parsing preferences."); + } + } + } + + nsCOMPtr<nsIProperties> dirSvc( + do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID, &rv)); + NS_ENSURE_SUCCESS(rv, rv); + + nsCOMPtr<nsISimpleEnumerator> list; + dirSvc->Get(NS_APP_PREFS_DEFAULTS_DIR_LIST, NS_GET_IID(nsISimpleEnumerator), + getter_AddRefs(list)); + if (list) { + bool hasMore; + while (NS_SUCCEEDED(list->HasMoreElements(&hasMore)) && hasMore) { + nsCOMPtr<nsISupports> elem; + list->GetNext(getter_AddRefs(elem)); + if (!elem) { + continue; + } + + nsCOMPtr<nsIFile> path = do_QueryInterface(elem); + if (!path) { + continue; + } + + // Do we care if a file provided by this process fails to load? + pref_LoadPrefsInDir(path, nullptr, 0); + } + } + + if (XRE_IsParentProcess()) { + SetupTelemetryPref(); + } + + if (aIsStartup) { + // Now that all prefs have their initial values, install the callbacks for + // `always`-mirrored static prefs. We do this now rather than in + // StaticPrefs::InitAll() so that the callbacks don't need to be traversed + // while we load prefs from data files. + StaticPrefs::StartObservingAlwaysPrefs(); + } + + NS_CreateServicesFromCategory(NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID, nullptr, + NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID); + + nsCOMPtr<nsIObserverService> observerService = services::GetObserverService(); + NS_ENSURE_SUCCESS(rv, rv); + + observerService->NotifyObservers(nullptr, NS_PREFSERVICE_APPDEFAULTS_TOPIC_ID, + nullptr); + + return NS_OK; +} + +/* static */ +nsresult Preferences::GetBool(const char* aPrefName, bool* aResult, + PrefValueKind aKind) { + MOZ_ASSERT(aResult); + return Internals::GetPrefValue(aPrefName, aResult, aKind); +} + +/* static */ +nsresult Preferences::GetInt(const char* aPrefName, int32_t* aResult, + PrefValueKind aKind) { + MOZ_ASSERT(aResult); + return Internals::GetPrefValue(aPrefName, aResult, aKind); +} + +/* static */ +nsresult Preferences::GetFloat(const char* aPrefName, float* aResult, + PrefValueKind aKind) { + MOZ_ASSERT(aResult); + return Internals::GetPrefValue(aPrefName, aResult, aKind); +} + +/* static */ +nsresult Preferences::GetCString(const char* aPrefName, nsACString& aResult, + PrefValueKind aKind) { + aResult.SetIsVoid(true); + return Internals::GetPrefValue(aPrefName, aResult, aKind); +} + +/* static */ +nsresult Preferences::GetString(const char* aPrefName, nsAString& aResult, + PrefValueKind aKind) { + nsAutoCString result; + nsresult rv = Preferences::GetCString(aPrefName, result, aKind); + if (NS_SUCCEEDED(rv)) { + CopyUTF8toUTF16(result, aResult); + } + return rv; +} + +/* static */ +nsresult Preferences::GetLocalizedCString(const char* aPrefName, + nsACString& aResult, + PrefValueKind aKind) { + nsAutoString result; + nsresult rv = GetLocalizedString(aPrefName, result, aKind); + if (NS_SUCCEEDED(rv)) { + CopyUTF16toUTF8(result, aResult); + } + return rv; +} + +/* static */ +nsresult Preferences::GetLocalizedString(const char* aPrefName, + nsAString& aResult, + PrefValueKind aKind) { + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + nsCOMPtr<nsIPrefLocalizedString> prefLocalString; + nsresult rv = GetRootBranch(aKind)->GetComplexValue( + aPrefName, NS_GET_IID(nsIPrefLocalizedString), + getter_AddRefs(prefLocalString)); + if (NS_SUCCEEDED(rv)) { + MOZ_ASSERT(prefLocalString, "Succeeded but the result is NULL"); + prefLocalString->GetData(aResult); + } + return rv; +} + +/* static */ +nsresult Preferences::GetComplex(const char* aPrefName, const nsIID& aType, + void** aResult, PrefValueKind aKind) { + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + return GetRootBranch(aKind)->GetComplexValue(aPrefName, aType, aResult); +} + +/* static */ +bool Preferences::GetBool(const char* aPrefName, bool aFallback, + PrefValueKind aKind) { + return Internals::GetPref(aPrefName, aFallback, aKind); +} + +/* static */ +int32_t Preferences::GetInt(const char* aPrefName, int32_t aFallback, + PrefValueKind aKind) { + return Internals::GetPref(aPrefName, aFallback, aKind); +} + +/* static */ +uint32_t Preferences::GetUint(const char* aPrefName, uint32_t aFallback, + PrefValueKind aKind) { + return Internals::GetPref(aPrefName, aFallback, aKind); +} + +/* static */ +float Preferences::GetFloat(const char* aPrefName, float aFallback, + PrefValueKind aKind) { + return Internals::GetPref(aPrefName, aFallback, aKind); +} + +/* static */ +nsresult Preferences::SetCString(const char* aPrefName, + const nsACString& aValue, + PrefValueKind aKind) { + ENSURE_PARENT_PROCESS("SetCString", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + if (aValue.Length() > MAX_PREF_LENGTH) { + return NS_ERROR_ILLEGAL_VALUE; + } + + // It's ok to stash a pointer to the temporary PromiseFlatCString's chars in + // pref because pref_SetPref() duplicates those chars. + PrefValue prefValue; + const nsCString& flat = PromiseFlatCString(aValue); + prefValue.mStringVal = flat.get(); + return pref_SetPref(nsDependentCString(aPrefName), PrefType::String, aKind, + prefValue, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ false); +} + +/* static */ +nsresult Preferences::SetBool(const char* aPrefName, bool aValue, + PrefValueKind aKind) { + ENSURE_PARENT_PROCESS("SetBool", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + PrefValue prefValue; + prefValue.mBoolVal = aValue; + return pref_SetPref(nsDependentCString(aPrefName), PrefType::Bool, aKind, + prefValue, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ false); +} + +/* static */ +nsresult Preferences::SetInt(const char* aPrefName, int32_t aValue, + PrefValueKind aKind) { + ENSURE_PARENT_PROCESS("SetInt", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + PrefValue prefValue; + prefValue.mIntVal = aValue; + return pref_SetPref(nsDependentCString(aPrefName), PrefType::Int, aKind, + prefValue, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ false); +} + +/* static */ +nsresult Preferences::SetComplex(const char* aPrefName, const nsIID& aType, + nsISupports* aValue, PrefValueKind aKind) { + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + return GetRootBranch(aKind)->SetComplexValue(aPrefName, aType, aValue); +} + +/* static */ +nsresult Preferences::Lock(const char* aPrefName) { + ENSURE_PARENT_PROCESS("Lock", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + const auto& prefName = nsDependentCString(aPrefName); + + Pref* pref; + MOZ_TRY_VAR(pref, + pref_LookupForModify(prefName, [](const PrefWrapper& aPref) { + return !aPref.IsLocked(); + })); + + if (pref) { + pref->SetIsLocked(true); + NotifyCallbacks(prefName, PrefWrapper(pref)); + } + + return NS_OK; +} + +/* static */ +nsresult Preferences::Unlock(const char* aPrefName) { + ENSURE_PARENT_PROCESS("Unlock", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + const auto& prefName = nsDependentCString(aPrefName); + + Pref* pref; + MOZ_TRY_VAR(pref, + pref_LookupForModify(prefName, [](const PrefWrapper& aPref) { + return aPref.IsLocked(); + })); + + if (pref) { + pref->SetIsLocked(false); + NotifyCallbacks(prefName, PrefWrapper(pref)); + } + + return NS_OK; +} + +/* static */ +bool Preferences::IsLocked(const char* aPrefName) { + NS_ENSURE_TRUE(InitStaticMembers(), false); + + Maybe<PrefWrapper> pref = pref_Lookup(aPrefName); + return pref.isSome() && pref->IsLocked(); +} + +/* static */ +nsresult Preferences::ClearUser(const char* aPrefName) { + ENSURE_PARENT_PROCESS("ClearUser", aPrefName); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + const auto& prefName = nsDependentCString{aPrefName}; + auto result = pref_LookupForModify( + prefName, [](const PrefWrapper& aPref) { return aPref.HasUserValue(); }); + if (result.isErr()) { + return NS_OK; + } + + if (Pref* pref = result.unwrap()) { + pref->ClearUserValue(); + + if (!pref->HasDefaultValue()) { + if (!gSharedMap || !gSharedMap->Has(pref->Name())) { + HashTable()->remove(aPrefName); + } else { + pref->SetType(PrefType::None); + } + + NotifyCallbacks(prefName); + } else { + NotifyCallbacks(prefName, PrefWrapper(pref)); + } + + Preferences::HandleDirty(); + } + return NS_OK; +} + +/* static */ +bool Preferences::HasUserValue(const char* aPrefName) { + NS_ENSURE_TRUE(InitStaticMembers(), false); + + Maybe<PrefWrapper> pref = pref_Lookup(aPrefName); + return pref.isSome() && pref->HasUserValue(); +} + +/* static */ +int32_t Preferences::GetType(const char* aPrefName) { + NS_ENSURE_TRUE(InitStaticMembers(), nsIPrefBranch::PREF_INVALID); + + if (!HashTable()) { + return PREF_INVALID; + } + + Maybe<PrefWrapper> pref = pref_Lookup(aPrefName); + if (!pref.isSome()) { + return PREF_INVALID; + } + + switch (pref->Type()) { + case PrefType::String: + return PREF_STRING; + + case PrefType::Int: + return PREF_INT; + + case PrefType::Bool: + return PREF_BOOL; + + default: + MOZ_CRASH(); + } +} + +/* static */ +nsresult Preferences::AddStrongObserver(nsIObserver* aObserver, + const nsACString& aPref) { + MOZ_ASSERT(aObserver); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + return sPreferences->mRootBranch->AddObserver(aPref, aObserver, false); +} + +/* static */ +nsresult Preferences::AddWeakObserver(nsIObserver* aObserver, + const nsACString& aPref) { + MOZ_ASSERT(aObserver); + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + return sPreferences->mRootBranch->AddObserver(aPref, aObserver, true); +} + +/* static */ +nsresult Preferences::RemoveObserver(nsIObserver* aObserver, + const nsACString& aPref) { + MOZ_ASSERT(aObserver); + if (sShutdown) { + MOZ_ASSERT(!sPreferences); + return NS_OK; // Observers have been released automatically. + } + NS_ENSURE_TRUE(sPreferences, NS_ERROR_NOT_AVAILABLE); + return sPreferences->mRootBranch->RemoveObserver(aPref, aObserver); +} + +template <typename T> +static void AssertNotMallocAllocated(T* aPtr) { +#if defined(DEBUG) && defined(MOZ_MEMORY) + jemalloc_ptr_info_t info; + jemalloc_ptr_info((void*)aPtr, &info); + MOZ_ASSERT(info.tag == TagUnknown); +#endif +} + +/* static */ +nsresult Preferences::AddStrongObservers(nsIObserver* aObserver, + const char** aPrefs) { + MOZ_ASSERT(aObserver); + for (uint32_t i = 0; aPrefs[i]; i++) { + AssertNotMallocAllocated(aPrefs[i]); + + nsCString pref; + pref.AssignLiteral(aPrefs[i], strlen(aPrefs[i])); + nsresult rv = AddStrongObserver(aObserver, pref); + NS_ENSURE_SUCCESS(rv, rv); + } + return NS_OK; +} + +/* static */ +nsresult Preferences::AddWeakObservers(nsIObserver* aObserver, + const char** aPrefs) { + MOZ_ASSERT(aObserver); + for (uint32_t i = 0; aPrefs[i]; i++) { + AssertNotMallocAllocated(aPrefs[i]); + + nsCString pref; + pref.AssignLiteral(aPrefs[i], strlen(aPrefs[i])); + nsresult rv = AddWeakObserver(aObserver, pref); + NS_ENSURE_SUCCESS(rv, rv); + } + return NS_OK; +} + +/* static */ +nsresult Preferences::RemoveObservers(nsIObserver* aObserver, + const char** aPrefs) { + MOZ_ASSERT(aObserver); + if (sShutdown) { + MOZ_ASSERT(!sPreferences); + return NS_OK; // Observers have been released automatically. + } + NS_ENSURE_TRUE(sPreferences, NS_ERROR_NOT_AVAILABLE); + + for (uint32_t i = 0; aPrefs[i]; i++) { + nsresult rv = RemoveObserver(aObserver, nsDependentCString(aPrefs[i])); + NS_ENSURE_SUCCESS(rv, rv); + } + return NS_OK; +} + +template <typename T> +/* static */ +nsresult Preferences::RegisterCallbackImpl(PrefChangedFunc aCallback, + T& aPrefNode, void* aData, + MatchKind aMatchKind, + bool aIsPriority) { + NS_ENSURE_ARG(aCallback); + + NS_ENSURE_TRUE(InitStaticMembers(), NS_ERROR_NOT_AVAILABLE); + + auto node = new CallbackNode(aPrefNode, aCallback, aData, aMatchKind); + + if (aIsPriority) { + // Add to the start of the list. + node->SetNext(gFirstCallback); + gFirstCallback = node; + if (!gLastPriorityNode) { + gLastPriorityNode = node; + } + } else { + // Add to the start of the non-priority part of the list. + if (gLastPriorityNode) { + node->SetNext(gLastPriorityNode->Next()); + gLastPriorityNode->SetNext(node); + } else { + node->SetNext(gFirstCallback); + gFirstCallback = node; + } + } + + return NS_OK; +} + +/* static */ +nsresult Preferences::RegisterCallback(PrefChangedFunc aCallback, + const nsACString& aPrefNode, void* aData, + MatchKind aMatchKind, bool aIsPriority) { + return RegisterCallbackImpl(aCallback, aPrefNode, aData, aMatchKind, + aIsPriority); +} + +/* static */ +nsresult Preferences::RegisterCallbacks(PrefChangedFunc aCallback, + const char** aPrefs, void* aData, + MatchKind aMatchKind) { + return RegisterCallbackImpl(aCallback, aPrefs, aData, aMatchKind); +} + +/* static */ +nsresult Preferences::RegisterCallbackAndCall(PrefChangedFunc aCallback, + const nsACString& aPref, + void* aClosure, + MatchKind aMatchKind) { + MOZ_ASSERT(aCallback); + nsresult rv = RegisterCallback(aCallback, aPref, aClosure, aMatchKind); + if (NS_SUCCEEDED(rv)) { + (*aCallback)(PromiseFlatCString(aPref).get(), aClosure); + } + return rv; +} + +/* static */ +nsresult Preferences::RegisterCallbacksAndCall(PrefChangedFunc aCallback, + const char** aPrefs, + void* aClosure) { + MOZ_ASSERT(aCallback); + + nsresult rv = + RegisterCallbacks(aCallback, aPrefs, aClosure, MatchKind::ExactMatch); + if (NS_SUCCEEDED(rv)) { + for (const char** ptr = aPrefs; *ptr; ptr++) { + (*aCallback)(*ptr, aClosure); + } + } + return rv; +} + +template <typename T> +/* static */ +nsresult Preferences::UnregisterCallbackImpl(PrefChangedFunc aCallback, + T& aPrefNode, void* aData, + MatchKind aMatchKind) { + MOZ_ASSERT(aCallback); + if (sShutdown) { + MOZ_ASSERT(!sPreferences); + return NS_OK; // Observers have been released automatically. + } + NS_ENSURE_TRUE(sPreferences, NS_ERROR_NOT_AVAILABLE); + + nsresult rv = NS_ERROR_FAILURE; + CallbackNode* node = gFirstCallback; + CallbackNode* prev_node = nullptr; + + while (node) { + if (node->Func() == aCallback && node->Data() == aData && + node->MatchKind() == aMatchKind && node->DomainIs(aPrefNode)) { + if (gCallbacksInProgress) { + // Postpone the node removal until after callbacks enumeration is + // finished. + node->ClearFunc(); + gShouldCleanupDeadNodes = true; + prev_node = node; + node = node->Next(); + } else { + node = pref_RemoveCallbackNode(node, prev_node); + } + rv = NS_OK; + } else { + prev_node = node; + node = node->Next(); + } + } + return rv; +} + +/* static */ +nsresult Preferences::UnregisterCallback(PrefChangedFunc aCallback, + const nsACString& aPrefNode, + void* aData, MatchKind aMatchKind) { + return UnregisterCallbackImpl<const nsACString&>(aCallback, aPrefNode, aData, + aMatchKind); +} + +/* static */ +nsresult Preferences::UnregisterCallbacks(PrefChangedFunc aCallback, + const char** aPrefs, void* aData, + MatchKind aMatchKind) { + return UnregisterCallbackImpl(aCallback, aPrefs, aData, aMatchKind); +} + +template <typename T> +static void AddMirrorCallback(T* aMirror, const nsACString& aPref) { + MOZ_ASSERT(NS_IsMainThread()); + + Internals::RegisterCallback<T>(aMirror, aPref); +} + +// Don't inline because it explodes compile times. +template <typename T> +static MOZ_NEVER_INLINE void AddMirror(T* aMirror, const nsACString& aPref, + StripAtomic<T> aDefault) { + *aMirror = Internals::GetPref(PromiseFlatCString(aPref).get(), aDefault); + AddMirrorCallback(aMirror, aPref); +} + +// The InitPref_*() functions below end in a `_<type>` suffix because they are +// used by the PREF macro definition in InitAll() below. + +static void InitPref_bool(const nsCString& aName, bool aDefaultValue) { + MOZ_ASSERT(XRE_IsParentProcess()); + PrefValue value; + value.mBoolVal = aDefaultValue; + pref_SetPref(aName, PrefType::Bool, PrefValueKind::Default, value, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ true); +} + +static void InitPref_int32_t(const nsCString& aName, int32_t aDefaultValue) { + MOZ_ASSERT(XRE_IsParentProcess()); + PrefValue value; + value.mIntVal = aDefaultValue; + pref_SetPref(aName, PrefType::Int, PrefValueKind::Default, value, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ true); +} + +static void InitPref_uint32_t(const nsCString& aName, uint32_t aDefaultValue) { + InitPref_int32_t(aName, int32_t(aDefaultValue)); +} + +static void InitPref_float(const nsCString& aName, float aDefaultValue) { + MOZ_ASSERT(XRE_IsParentProcess()); + PrefValue value; + // Convert the value in a locale-independent way, including a trailing ".0" + // if necessary to distinguish floating-point from integer prefs when viewing + // them in about:config. + nsAutoCString defaultValue; + defaultValue.AppendFloat(aDefaultValue); + if (!defaultValue.Contains('.') && !defaultValue.Contains('e')) { + defaultValue.AppendLiteral(".0"); + } + value.mStringVal = defaultValue.get(); + pref_SetPref(aName, PrefType::String, PrefValueKind::Default, value, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ true); +} + +static void InitPref_String(const nsCString& aName, const char* aDefaultValue) { + MOZ_ASSERT(XRE_IsParentProcess()); + PrefValue value; + value.mStringVal = aDefaultValue; + pref_SetPref(aName, PrefType::String, PrefValueKind::Default, value, + /* isSticky */ false, + /* isLocked */ false, + /* fromInit */ true); +} + +static void InitPref(const nsCString& aName, bool aDefaultValue) { + InitPref_bool(aName, aDefaultValue); +} +static void InitPref(const nsCString& aName, int32_t aDefaultValue) { + InitPref_int32_t(aName, aDefaultValue); +} +static void InitPref(const nsCString& aName, uint32_t aDefaultValue) { + InitPref_uint32_t(aName, aDefaultValue); +} +static void InitPref(const nsCString& aName, float aDefaultValue) { + InitPref_float(aName, aDefaultValue); +} + +template <typename T> +static void InitAlwaysPref(const nsCString& aName, T* aCache, + StripAtomic<T> aDefaultValue) { + // Only called in the parent process. Set/reset the pref value and the + // `always` mirror to the default value. + // `once` mirrors will be initialized lazily in InitOncePrefs(). + InitPref(aName, aDefaultValue); + *aCache = aDefaultValue; +} + +static Atomic<bool> sOncePrefRead(false); +static StaticMutex sOncePrefMutex; + +namespace StaticPrefs { + +void MaybeInitOncePrefs() { + if (MOZ_LIKELY(sOncePrefRead)) { + // `once`-mirrored prefs have already been initialized to their default + // value. + return; + } + StaticMutexAutoLock lock(sOncePrefMutex); + if (NS_IsMainThread()) { + InitOncePrefs(); + } else { + RefPtr<Runnable> runnable = NS_NewRunnableFunction( + "Preferences::MaybeInitOncePrefs", [&]() { InitOncePrefs(); }); + // This logic needs to run on the main thread + SyncRunnable::DispatchToThread(GetMainThreadSerialEventTarget(), runnable); + } + sOncePrefRead = true; +} + +// For mirrored prefs we generate a variable definition. +#define NEVER_PREF(name, cpp_type, value) +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, default_value) \ + cpp_type sMirror_##full_id(default_value); +#define ONCE_PREF(name, base_id, full_id, cpp_type, default_value) \ + cpp_type sMirror_##full_id(default_value); +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF + +static void InitAll() { + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(XRE_IsParentProcess()); + + // For all prefs we generate some initialization code. + // + // The InitPref_*() functions have a type suffix to avoid ambiguity between + // prefs having int32_t and float default values. That suffix is not needed + // for the InitAlwaysPref() functions because they take a pointer parameter, + // which prevents automatic int-to-float coercion. +#define NEVER_PREF(name, cpp_type, value) \ + InitPref_##cpp_type(name ""_ns, value); +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, value) \ + InitAlwaysPref(name ""_ns, &sMirror_##full_id, value); +#define ONCE_PREF(name, base_id, full_id, cpp_type, value) \ + InitPref_##cpp_type(name ""_ns, value); +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF +} + +static void StartObservingAlwaysPrefs() { + MOZ_ASSERT(NS_IsMainThread()); + + // Call AddMirror so that our mirrors for `always` prefs will stay updated. + // The call to AddMirror re-reads the current pref value into the mirror, so + // our mirror will now be up-to-date even if some of the prefs have changed + // since the call to InitAll(). +#define NEVER_PREF(name, cpp_type, value) +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, value) \ + AddMirror(&sMirror_##full_id, name ""_ns, sMirror_##full_id); +#define ONCE_PREF(name, base_id, full_id, cpp_type, value) +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF +} + +static void InitOncePrefs() { + // For `once`-mirrored prefs we generate some initialization code. This is + // done in case the pref value was updated when reading pref data files. It's + // necessary because we don't have callbacks registered for `once`-mirrored + // prefs. + // + // In debug builds, we also install a mechanism that can check if the + // preference value is modified after `once`-mirrored prefs are initialized. + // In tests this would indicate a likely misuse of a `once`-mirrored pref and + // suggest that it should instead be `always`-mirrored. +#define NEVER_PREF(name, cpp_type, value) +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, value) +#ifdef DEBUG +# define ONCE_PREF(name, base_id, full_id, cpp_type, value) \ + { \ + MOZ_ASSERT(gOnceStaticPrefsAntiFootgun); \ + sMirror_##full_id = Internals::GetPref(name, cpp_type(value)); \ + auto checkPref = [&]() { \ + MOZ_ASSERT(sOncePrefRead); \ + cpp_type staticPrefValue = full_id(); \ + cpp_type preferenceValue = \ + Internals::GetPref(GetPrefName_##base_id(), cpp_type(value)); \ + MOZ_ASSERT(staticPrefValue == preferenceValue, \ + "Preference '" name \ + "' got modified since StaticPrefs::" #full_id \ + " was initialized. Consider using an `always` mirror kind " \ + "instead"); \ + }; \ + gOnceStaticPrefsAntiFootgun->insert( \ + std::pair<const char*, AntiFootgunCallback>(GetPrefName_##base_id(), \ + std::move(checkPref))); \ + } +#else +# define ONCE_PREF(name, base_id, full_id, cpp_type, value) \ + sMirror_##full_id = Internals::GetPref(name, cpp_type(value)); +#endif + +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF +} + +} // namespace StaticPrefs + +static MOZ_MAYBE_UNUSED void SaveOncePrefToSharedMap( + SharedPrefMapBuilder& aBuilder, const nsACString& aName, bool aValue) { + auto oncePref = MakeUnique<Pref>(aName); + oncePref->SetType(PrefType::Bool); + oncePref->SetIsSkippedByIteration(true); + bool valueChanged = false; + MOZ_ALWAYS_SUCCEEDS( + oncePref->SetDefaultValue(PrefType::Bool, PrefValue(aValue), + /* isSticky */ true, + /* isLocked */ true, &valueChanged)); + oncePref->AddToMap(aBuilder); +} + +static MOZ_MAYBE_UNUSED void SaveOncePrefToSharedMap( + SharedPrefMapBuilder& aBuilder, const nsACString& aName, int32_t aValue) { + auto oncePref = MakeUnique<Pref>(aName); + oncePref->SetType(PrefType::Int); + oncePref->SetIsSkippedByIteration(true); + bool valueChanged = false; + MOZ_ALWAYS_SUCCEEDS( + oncePref->SetDefaultValue(PrefType::Int, PrefValue(aValue), + /* isSticky */ true, + /* isLocked */ true, &valueChanged)); + oncePref->AddToMap(aBuilder); +} + +static MOZ_MAYBE_UNUSED void SaveOncePrefToSharedMap( + SharedPrefMapBuilder& aBuilder, const nsACString& aName, uint32_t aValue) { + SaveOncePrefToSharedMap(aBuilder, aName, int32_t(aValue)); +} + +static MOZ_MAYBE_UNUSED void SaveOncePrefToSharedMap( + SharedPrefMapBuilder& aBuilder, const nsACString& aName, float aValue) { + auto oncePref = MakeUnique<Pref>(aName); + oncePref->SetType(PrefType::String); + oncePref->SetIsSkippedByIteration(true); + nsAutoCString value; + value.AppendFloat(aValue); + bool valueChanged = false; + // It's ok to stash a pointer to the temporary PromiseFlatCString's chars in + // pref because pref_SetPref() duplicates those chars. + const nsCString& flat = PromiseFlatCString(value); + MOZ_ALWAYS_SUCCEEDS( + oncePref->SetDefaultValue(PrefType::String, PrefValue(flat.get()), + /* isSticky */ true, + /* isLocked */ true, &valueChanged)); + oncePref->AddToMap(aBuilder); +} + +#define ONCE_PREF_NAME(name) "$$$" name "$$$" + +namespace StaticPrefs { + +static void RegisterOncePrefs(SharedPrefMapBuilder& aBuilder) { + MOZ_ASSERT(XRE_IsParentProcess()); + MOZ_DIAGNOSTIC_ASSERT(!gSharedMap, + "Must be called before gSharedMap has been created"); + MaybeInitOncePrefs(); + + // For `once`-mirrored prefs we generate a save call, which saves the value + // as it was at parent startup. It is stored in a special (hidden and locked) + // entry in the global SharedPreferenceMap. In order for the entry to be + // hidden and not appear in about:config nor ever be stored to disk, we set + // its IsSkippedByIteration flag to true. We also distinguish it by adding a + // "$$$" prefix and suffix to the preference name. +#define NEVER_PREF(name, cpp_type, value) +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, value) +#define ONCE_PREF(name, base_id, full_id, cpp_type, value) \ + SaveOncePrefToSharedMap(aBuilder, ONCE_PREF_NAME(name) ""_ns, \ + cpp_type(sMirror_##full_id)); +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF +} + +static void InitStaticPrefsFromShared() { + MOZ_ASSERT(!XRE_IsParentProcess()); + MOZ_DIAGNOSTIC_ASSERT(gSharedMap, + "Must be called once gSharedMap has been created"); + + // For mirrored static prefs we generate some initialization code. Each + // mirror variable is already initialized in the binary with the default + // value. If the pref value hasn't changed from the default in the main + // process (the common case) then the overwriting here won't change the + // mirror variable's value. + // + // Note that the MOZ_ASSERT calls below can fail in one obscure case: when a + // Firefox update occurs and we get a main process from the old binary (with + // static prefs {A,B,C,D}) plus a new content process from the new binary + // (with static prefs {A,B,C,D,E}). The content process' call to + // GetSharedPrefValue() for pref E will fail because the shared pref map was + // created by the main process, which doesn't have pref E. + // + // This silent failure is safe. The mirror variable for pref E is already + // initialized to the default value in the content process, and the main + // process cannot have changed pref E because it doesn't know about it! + // + // Nonetheless, it's useful to have the MOZ_ASSERT here for testing of debug + // builds, where this scenario involving inconsistent binaries should not + // occur. +#define NEVER_PREF(name, cpp_type, value) +#define ALWAYS_PREF(name, base_id, full_id, cpp_type, value) \ + { \ + StripAtomic<cpp_type> val; \ + DebugOnly<nsresult> rv = Internals::GetSharedPrefValue(name, &val); \ + MOZ_ASSERT(NS_SUCCEEDED(rv)); \ + StaticPrefs::sMirror_##full_id = val; \ + } +#define ONCE_PREF(name, base_id, full_id, cpp_type, value) \ + { \ + cpp_type val; \ + DebugOnly<nsresult> rv = \ + Internals::GetSharedPrefValue(ONCE_PREF_NAME(name), &val); \ + MOZ_ASSERT(NS_SUCCEEDED(rv)); \ + StaticPrefs::sMirror_##full_id = val; \ + } +#include "mozilla/StaticPrefListAll.h" +#undef NEVER_PREF +#undef ALWAYS_PREF +#undef ONCE_PREF + + // `once`-mirrored prefs have been set to their value in the step above and + // outside the parent process they are immutable. We set sOncePrefRead so + // that we can directly skip any lazy initializations. + sOncePrefRead = true; +} + +} // namespace StaticPrefs + +} // namespace mozilla + +#undef ENSURE_PARENT_PROCESS + +//=========================================================================== +// Module and factory stuff +//=========================================================================== + +NS_IMPL_COMPONENT_FACTORY(nsPrefLocalizedString) { + auto str = MakeRefPtr<nsPrefLocalizedString>(); + if (NS_SUCCEEDED(str->Init())) { + return str.forget().downcast<nsISupports>(); + } + return nullptr; +} + +namespace mozilla { + +void UnloadPrefsModule() { Preferences::Shutdown(); } + +} // namespace mozilla + +// This file contains the C wrappers for the C++ static pref getters, as used +// by Rust code. +#include "init/StaticPrefsCGetters.cpp" |