summaryrefslogtreecommitdiffstats
path: root/xpcom/ds/nsTHashtable.h
diff options
context:
space:
mode:
Diffstat (limited to 'xpcom/ds/nsTHashtable.h')
-rw-r--r--xpcom/ds/nsTHashtable.h966
1 files changed, 966 insertions, 0 deletions
diff --git a/xpcom/ds/nsTHashtable.h b/xpcom/ds/nsTHashtable.h
new file mode 100644
index 0000000000..d4a385551f
--- /dev/null
+++ b/xpcom/ds/nsTHashtable.h
@@ -0,0 +1,966 @@
+/* -*- 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/. */
+
+// See the comment at the top of mfbt/HashTable.h for a comparison between
+// PLDHashTable and mozilla::HashTable.
+
+#ifndef nsTHashtable_h__
+#define nsTHashtable_h__
+
+#include <iterator>
+#include <new>
+#include <type_traits>
+#include <utility>
+
+#include "PLDHashTable.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Maybe.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/OperatorNewExtensions.h"
+#include "mozilla/PodOperations.h"
+#include "mozilla/fallible.h"
+#include "nsPointerHashKeys.h"
+#include "nsTArrayForwardDeclare.h"
+
+template <class EntryType>
+class nsTHashtable;
+
+namespace detail {
+class nsTHashtableIteratorBase {
+ public:
+ using EndIteratorTag = PLDHashTable::Iterator::EndIteratorTag;
+
+ nsTHashtableIteratorBase(nsTHashtableIteratorBase&& aOther) = default;
+
+ nsTHashtableIteratorBase& operator=(nsTHashtableIteratorBase&& aOther) {
+ // User-defined because the move assignment operator is deleted in
+ // PLDHashtable::Iterator.
+ return operator=(static_cast<const nsTHashtableIteratorBase&>(aOther));
+ }
+
+ nsTHashtableIteratorBase(const nsTHashtableIteratorBase& aOther)
+ : mIterator{aOther.mIterator.Clone()} {}
+ nsTHashtableIteratorBase& operator=(const nsTHashtableIteratorBase& aOther) {
+ // Since PLDHashTable::Iterator has no assignment operator, we destroy and
+ // recreate mIterator.
+ mIterator.~Iterator();
+ new (&mIterator) PLDHashTable::Iterator(aOther.mIterator.Clone());
+ return *this;
+ }
+
+ explicit nsTHashtableIteratorBase(PLDHashTable::Iterator aFrom)
+ : mIterator{std::move(aFrom)} {}
+
+ explicit nsTHashtableIteratorBase(const PLDHashTable& aTable)
+ : mIterator{&const_cast<PLDHashTable&>(aTable)} {}
+
+ nsTHashtableIteratorBase(const PLDHashTable& aTable, EndIteratorTag aTag)
+ : mIterator{&const_cast<PLDHashTable&>(aTable), aTag} {}
+
+ bool operator==(const nsTHashtableIteratorBase& aRhs) const {
+ return mIterator == aRhs.mIterator;
+ }
+ bool operator!=(const nsTHashtableIteratorBase& aRhs) const {
+ return !(*this == aRhs);
+ }
+
+ protected:
+ PLDHashTable::Iterator mIterator;
+};
+
+// STL-style iterators to allow the use in range-based for loops, e.g.
+template <typename T>
+class nsTHashtableEntryIterator : public nsTHashtableIteratorBase {
+ friend class nsTHashtable<std::remove_const_t<T>>;
+
+ public:
+ using iterator_category = std::forward_iterator_tag;
+ using value_type = T;
+ using difference_type = int32_t;
+ using pointer = value_type*;
+ using reference = value_type&;
+
+ using iterator_type = nsTHashtableEntryIterator;
+ using const_iterator_type = nsTHashtableEntryIterator<const T>;
+
+ using nsTHashtableIteratorBase::nsTHashtableIteratorBase;
+
+ value_type* operator->() const {
+ return static_cast<value_type*>(mIterator.Get());
+ }
+ value_type& operator*() const {
+ return *static_cast<value_type*>(mIterator.Get());
+ }
+
+ iterator_type& operator++() {
+ mIterator.Next();
+ return *this;
+ }
+ iterator_type operator++(int) {
+ iterator_type it = *this;
+ ++*this;
+ return it;
+ }
+
+ operator const_iterator_type() const {
+ return const_iterator_type{mIterator.Clone()};
+ }
+};
+
+template <typename EntryType>
+class nsTHashtableKeyIterator : public nsTHashtableIteratorBase {
+ friend class nsTHashtable<EntryType>;
+
+ public:
+ using iterator_category = std::forward_iterator_tag;
+ using value_type = const std::decay_t<typename EntryType::KeyType>;
+ using difference_type = int32_t;
+ using pointer = value_type*;
+ using reference = value_type&;
+
+ using iterator_type = nsTHashtableKeyIterator;
+ using const_iterator_type = nsTHashtableKeyIterator;
+
+ using nsTHashtableIteratorBase::nsTHashtableIteratorBase;
+
+ value_type* operator->() const {
+ return &static_cast<const EntryType*>(mIterator.Get())->GetKey();
+ }
+ decltype(auto) operator*() const {
+ return static_cast<const EntryType*>(mIterator.Get())->GetKey();
+ }
+
+ iterator_type& operator++() {
+ mIterator.Next();
+ return *this;
+ }
+ iterator_type operator++(int) {
+ iterator_type it = *this;
+ ++*this;
+ return it;
+ }
+};
+
+template <typename EntryType>
+class nsTHashtableKeyRange {
+ public:
+ using IteratorType = nsTHashtableKeyIterator<EntryType>;
+ using iterator = IteratorType;
+
+ explicit nsTHashtableKeyRange(const PLDHashTable& aHashtable)
+ : mHashtable{aHashtable} {}
+
+ auto begin() const { return IteratorType{mHashtable}; }
+ auto end() const {
+ return IteratorType{mHashtable, typename IteratorType::EndIteratorTag{}};
+ }
+ auto cbegin() const { return begin(); }
+ auto cend() const { return end(); }
+
+ uint32_t Count() const { return mHashtable.EntryCount(); }
+
+ private:
+ const PLDHashTable& mHashtable;
+};
+
+template <typename EntryType>
+auto RangeSize(const ::detail::nsTHashtableKeyRange<EntryType>& aRange) {
+ return aRange.Count();
+}
+
+} // namespace detail
+
+/**
+ * a base class for templated hashtables.
+ *
+ * Clients will rarely need to use this class directly. Check the derived
+ * classes first, to see if they will meet your needs.
+ *
+ * @param EntryType the templated entry-type class that is managed by the
+ * hashtable. <code>EntryType</code> must extend the following declaration,
+ * and <strong>must not declare any virtual functions or derive from classes
+ * with virtual functions.</strong> Any vtable pointer would break the
+ * PLDHashTable code.
+ *<pre> class EntryType : public PLDHashEntryHdr
+ * {
+ * public: or friend nsTHashtable<EntryType>;
+ * // KeyType is what we use when Get()ing or Put()ing this entry
+ * // this should either be a simple datatype (uint32_t, nsISupports*) or
+ * // a const reference (const nsAString&)
+ * typedef something KeyType;
+ * // KeyTypePointer is the pointer-version of KeyType, because
+ * // PLDHashTable.h requires keys to cast to <code>const void*</code>
+ * typedef const something* KeyTypePointer;
+ *
+ * EntryType(KeyTypePointer aKey);
+ *
+ * // A copy or C++11 Move constructor must be defined, even if
+ * // AllowMemMove() == true, otherwise you will cause link errors.
+ * EntryType(const EntryType& aEnt); // Either this...
+ * EntryType(EntryType&& aEnt); // ...or this
+ *
+ * // the destructor must be defined... or you will cause link errors!
+ * ~EntryType();
+ *
+ * // KeyEquals(): does this entry match this key?
+ * bool KeyEquals(KeyTypePointer aKey) const;
+ *
+ * // KeyToPointer(): Convert KeyType to KeyTypePointer
+ * static KeyTypePointer KeyToPointer(KeyType aKey);
+ *
+ * // HashKey(): calculate the hash number
+ * static PLDHashNumber HashKey(KeyTypePointer aKey);
+ *
+ * // ALLOW_MEMMOVE can we move this class with memmove(), or do we have
+ * // to use the copy constructor?
+ * enum { ALLOW_MEMMOVE = true/false };
+ * }</pre>
+ *
+ * @see nsInterfaceHashtable
+ * @see nsClassHashtable
+ * @see nsTHashMap
+ * @author "Benjamin Smedberg <bsmedberg@covad.net>"
+ */
+
+template <class EntryType>
+class MOZ_NEEDS_NO_VTABLE_TYPE nsTHashtable {
+ typedef mozilla::fallible_t fallible_t;
+ static_assert(std::is_pointer_v<typename EntryType::KeyTypePointer>,
+ "KeyTypePointer should be a pointer");
+
+ public:
+ // Separate constructors instead of default aInitLength parameter since
+ // otherwise the default no-arg constructor isn't found.
+ nsTHashtable()
+ : mTable(Ops(), sizeof(EntryType), PLDHashTable::kDefaultInitialLength) {}
+ explicit nsTHashtable(uint32_t aInitLength)
+ : mTable(Ops(), sizeof(EntryType), aInitLength) {}
+
+ /**
+ * destructor, cleans up and deallocates
+ */
+ ~nsTHashtable() = default;
+
+ nsTHashtable(nsTHashtable<EntryType>&& aOther);
+ nsTHashtable<EntryType>& operator=(nsTHashtable<EntryType>&& aOther);
+
+ nsTHashtable(const nsTHashtable<EntryType>&) = delete;
+ nsTHashtable& operator=(const nsTHashtable<EntryType>&) = delete;
+
+ /**
+ * Return the generation number for the table. This increments whenever
+ * the table data items are moved.
+ */
+ uint32_t GetGeneration() const { return mTable.Generation(); }
+
+ /**
+ * KeyType is typedef'ed for ease of use.
+ */
+ typedef typename EntryType::KeyType KeyType;
+
+ /**
+ * KeyTypePointer is typedef'ed for ease of use.
+ */
+ typedef typename EntryType::KeyTypePointer KeyTypePointer;
+
+ /**
+ * Return the number of entries in the table.
+ * @return number of entries
+ */
+ uint32_t Count() const { return mTable.EntryCount(); }
+
+ /**
+ * Return true if the hashtable is empty.
+ */
+ bool IsEmpty() const { return Count() == 0; }
+
+ /**
+ * Get the entry associated with a key.
+ * @param aKey the key to retrieve
+ * @return pointer to the entry class, if the key exists; nullptr if the
+ * key doesn't exist
+ */
+ EntryType* GetEntry(KeyType aKey) const {
+ return static_cast<EntryType*>(
+ mTable.Search(EntryType::KeyToPointer(aKey)));
+ }
+
+ /**
+ * Return true if an entry for the given key exists, false otherwise.
+ * @param aKey the key to retrieve
+ * @return true if the key exists, false if the key doesn't exist
+ */
+ bool Contains(KeyType aKey) const { return !!GetEntry(aKey); }
+
+ /**
+ * Infallibly get the entry associated with a key, or create a new entry,
+ * @param aKey the key to retrieve
+ * @return pointer to the entry retrieved; never nullptr
+ */
+ EntryType* PutEntry(KeyType aKey) {
+ // Infallible WithEntryHandle.
+ return WithEntryHandle(
+ aKey, [](auto entryHandle) { return entryHandle.OrInsert(); });
+ }
+
+ /**
+ * Fallibly get the entry associated with a key, or create a new entry,
+ * @param aKey the key to retrieve
+ * @return pointer to the entry retrieved; nullptr only if memory can't
+ * be allocated
+ */
+ [[nodiscard]] EntryType* PutEntry(KeyType aKey, const fallible_t& aFallible) {
+ return WithEntryHandle(aKey, aFallible, [](auto maybeEntryHandle) {
+ return maybeEntryHandle ? maybeEntryHandle->OrInsert() : nullptr;
+ });
+ }
+
+ /**
+ * Get the entry associated with a key, or create a new entry using infallible
+ * allocation and insert that.
+ * @param aKey the key to retrieve
+ * @param aEntry will be assigned (if non-null) to the entry that was
+ * found or created
+ * @return true if a new entry was created, or false if an existing entry
+ * was found
+ */
+ [[nodiscard]] bool EnsureInserted(KeyType aKey,
+ EntryType** aEntry = nullptr) {
+ auto oldCount = Count();
+ EntryType* entry = PutEntry(aKey);
+ if (aEntry) {
+ *aEntry = entry;
+ }
+ return oldCount != Count();
+ }
+
+ /**
+ * Remove the entry associated with a key.
+ * @param aKey of the entry to remove
+ */
+ void RemoveEntry(KeyType aKey) {
+ mTable.Remove(EntryType::KeyToPointer(aKey));
+ }
+
+ /**
+ * Lookup the entry associated with aKey and remove it if found, otherwise
+ * do nothing.
+ * @param aKey of the entry to remove
+ * @return true if an entry was found and removed, or false if no entry
+ * was found for aKey
+ */
+ bool EnsureRemoved(KeyType aKey) {
+ auto* entry = GetEntry(aKey);
+ if (entry) {
+ RemoveEntry(entry);
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * Remove the entry associated with a key.
+ * @param aEntry the entry-pointer to remove (obtained from GetEntry)
+ */
+ void RemoveEntry(EntryType* aEntry) { mTable.RemoveEntry(aEntry); }
+
+ /**
+ * Remove the entry associated with a key, but don't resize the hashtable.
+ * This is a low-level method, and is not recommended unless you know what
+ * you're doing. If you use it, please add a comment explaining why you
+ * didn't use RemoveEntry().
+ * @param aEntry the entry-pointer to remove (obtained from GetEntry)
+ */
+ void RawRemoveEntry(EntryType* aEntry) { mTable.RawRemove(aEntry); }
+
+ protected:
+ class EntryHandle {
+ public:
+ EntryHandle(EntryHandle&& aOther) = default;
+ ~EntryHandle() = default;
+
+ EntryHandle(const EntryHandle&) = delete;
+ EntryHandle& operator=(const EntryHandle&) = delete;
+ EntryHandle& operator=(const EntryHandle&&) = delete;
+
+ KeyType Key() const { return mKey; }
+
+ bool HasEntry() const { return mEntryHandle.HasEntry(); }
+
+ explicit operator bool() const { return mEntryHandle.operator bool(); }
+
+ EntryType* Entry() { return static_cast<EntryType*>(mEntryHandle.Entry()); }
+
+ void Insert() { InsertInternal(); }
+
+ EntryType* OrInsert() {
+ if (!HasEntry()) {
+ Insert();
+ }
+ return Entry();
+ }
+
+ void Remove() { mEntryHandle.Remove(); }
+
+ void OrRemove() { mEntryHandle.OrRemove(); }
+
+ protected:
+ template <typename... Args>
+ void InsertInternal(Args&&... aArgs) {
+ MOZ_RELEASE_ASSERT(!HasEntry());
+ mEntryHandle.Insert([&](PLDHashEntryHdr* entry) {
+ new (mozilla::KnownNotNull, entry) EntryType(
+ EntryType::KeyToPointer(mKey), std::forward<Args>(aArgs)...);
+ });
+ }
+
+ private:
+ friend class nsTHashtable;
+
+ EntryHandle(KeyType aKey, PLDHashTable::EntryHandle&& aEntryHandle)
+ : mKey(aKey), mEntryHandle(std::move(aEntryHandle)) {}
+
+ KeyType mKey;
+ PLDHashTable::EntryHandle mEntryHandle;
+ };
+
+ template <class F>
+ auto WithEntryHandle(KeyType aKey, F&& aFunc)
+ -> std::invoke_result_t<F, EntryHandle&&> {
+ return this->mTable.WithEntryHandle(
+ EntryType::KeyToPointer(aKey),
+ [&aKey, &aFunc](auto entryHandle) -> decltype(auto) {
+ return std::forward<F>(aFunc)(
+ EntryHandle{aKey, std::move(entryHandle)});
+ });
+ }
+
+ template <class F>
+ auto WithEntryHandle(KeyType aKey, const mozilla::fallible_t& aFallible,
+ F&& aFunc)
+ -> std::invoke_result_t<F, mozilla::Maybe<EntryHandle>&&> {
+ return this->mTable.WithEntryHandle(
+ EntryType::KeyToPointer(aKey), aFallible,
+ [&aKey, &aFunc](auto maybeEntryHandle) {
+ return std::forward<F>(aFunc)(
+ maybeEntryHandle
+ ? mozilla::Some(EntryHandle{aKey, maybeEntryHandle.extract()})
+ : mozilla::Nothing());
+ });
+ }
+
+ public:
+ class ConstIterator {
+ public:
+ explicit ConstIterator(nsTHashtable* aTable)
+ : mBaseIterator(&aTable->mTable) {}
+ ~ConstIterator() = default;
+
+ KeyType Key() const { return Get()->GetKey(); }
+
+ const EntryType* Get() const {
+ return static_cast<const EntryType*>(mBaseIterator.Get());
+ }
+
+ bool Done() const { return mBaseIterator.Done(); }
+ void Next() { mBaseIterator.Next(); }
+
+ ConstIterator() = delete;
+ ConstIterator(const ConstIterator&) = delete;
+ ConstIterator(ConstIterator&& aOther) = delete;
+ ConstIterator& operator=(const ConstIterator&) = delete;
+ ConstIterator& operator=(ConstIterator&&) = delete;
+
+ protected:
+ PLDHashTable::Iterator mBaseIterator;
+ };
+
+ // This is an iterator that also allows entry removal. Example usage:
+ //
+ // for (auto iter = table.Iter(); !iter.Done(); iter.Next()) {
+ // Entry* entry = iter.Get();
+ // // ... do stuff with |entry| ...
+ // // ... possibly call iter.Remove() once ...
+ // }
+ //
+ class Iterator final : public ConstIterator {
+ public:
+ using ConstIterator::ConstIterator;
+
+ using ConstIterator::Get;
+
+ EntryType* Get() const {
+ return static_cast<EntryType*>(this->mBaseIterator.Get());
+ }
+
+ void Remove() { this->mBaseIterator.Remove(); }
+ };
+
+ Iterator Iter() { return Iterator(this); }
+
+ ConstIterator ConstIter() const {
+ return ConstIterator(const_cast<nsTHashtable*>(this));
+ }
+
+ using const_iterator = ::detail::nsTHashtableEntryIterator<const EntryType>;
+ using iterator = ::detail::nsTHashtableEntryIterator<EntryType>;
+
+ iterator begin() { return iterator{mTable}; }
+ const_iterator begin() const { return const_iterator{mTable}; }
+ const_iterator cbegin() const { return begin(); }
+ iterator end() {
+ return iterator{mTable, typename iterator::EndIteratorTag{}};
+ }
+ const_iterator end() const {
+ return const_iterator{mTable, typename const_iterator::EndIteratorTag{}};
+ }
+ const_iterator cend() const { return end(); }
+
+ void Remove(const_iterator& aIter) { aIter.mIterator.Remove(); }
+
+ /**
+ * Return a range of the keys (of KeyType). Note this range iterates over the
+ * keys in place, so modifications to the nsTHashtable invalidate the range
+ * while it's iterated, except when calling Remove() with a key iterator
+ * derived from that range.
+ */
+ auto Keys() const {
+ return ::detail::nsTHashtableKeyRange<EntryType>{mTable};
+ }
+
+ /**
+ * Remove an entry from a key range, specified via a key iterator, e.g.
+ *
+ * for (auto it = hash.Keys().begin(), end = hash.Keys().end();
+ * it != end; * ++it) {
+ * if (*it > 42) { hash.Remove(it); }
+ * }
+ */
+ void Remove(::detail::nsTHashtableKeyIterator<EntryType>& aIter) {
+ aIter.mIterator.Remove();
+ }
+
+ /**
+ * Remove all entries, return hashtable to "pristine" state. It's
+ * conceptually the same as calling the destructor and then re-calling the
+ * constructor.
+ */
+ void Clear() { mTable.Clear(); }
+
+ /**
+ * Measure the size of the table's entry storage. Does *not* measure anything
+ * hanging off table entries; hence the "Shallow" prefix. To measure that,
+ * either use SizeOfExcludingThis() or iterate manually over the entries,
+ * calling SizeOfExcludingThis() on each one.
+ *
+ * @param aMallocSizeOf the function used to measure heap-allocated blocks
+ * @return the measured shallow size of the table
+ */
+ size_t ShallowSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+ return mTable.ShallowSizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ /**
+ * Like ShallowSizeOfExcludingThis, but includes sizeof(*this).
+ */
+ size_t ShallowSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+ return aMallocSizeOf(this) + ShallowSizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ /**
+ * This is a "deep" measurement of the table. To use it, |EntryType| must
+ * define SizeOfExcludingThis, and that method will be called on all live
+ * entries.
+ */
+ size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+ size_t n = ShallowSizeOfExcludingThis(aMallocSizeOf);
+ for (auto iter = ConstIter(); !iter.Done(); iter.Next()) {
+ n += (*iter.Get()).SizeOfExcludingThis(aMallocSizeOf);
+ }
+ return n;
+ }
+
+ /**
+ * Like SizeOfExcludingThis, but includes sizeof(*this).
+ */
+ size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const {
+ return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+ }
+
+ /**
+ * Swap the elements in this hashtable with the elements in aOther.
+ */
+ void SwapElements(nsTHashtable<EntryType>& aOther) {
+ MOZ_ASSERT_IF(this->mTable.Ops() && aOther.mTable.Ops(),
+ this->mTable.Ops() == aOther.mTable.Ops());
+ std::swap(this->mTable, aOther.mTable);
+ }
+
+ /**
+ * Mark the table as constant after initialization.
+ *
+ * This will prevent assertions when a read-only hash is accessed on multiple
+ * threads without synchronization.
+ */
+ void MarkImmutable() { mTable.MarkImmutable(); }
+
+ protected:
+ PLDHashTable mTable;
+
+ static PLDHashNumber s_HashKey(const void* aKey);
+
+ static bool s_MatchEntry(const PLDHashEntryHdr* aEntry, const void* aKey);
+
+ static void s_CopyEntry(PLDHashTable* aTable, const PLDHashEntryHdr* aFrom,
+ PLDHashEntryHdr* aTo);
+
+ static void s_ClearEntry(PLDHashTable* aTable, PLDHashEntryHdr* aEntry);
+
+ private:
+ // copy constructor, not implemented
+ nsTHashtable(nsTHashtable<EntryType>& aToCopy) = delete;
+
+ /**
+ * Gets the table's ops.
+ */
+ static const PLDHashTableOps* Ops();
+
+ // assignment operator, not implemented
+ nsTHashtable<EntryType>& operator=(nsTHashtable<EntryType>& aToEqual) =
+ delete;
+};
+
+namespace mozilla {
+namespace detail {
+
+// Like PLDHashTable::MoveEntryStub, but specialized for fixed N (i.e. the size
+// of the entries in the hashtable). Saves a memory read to figure out the size
+// from the table and gives the compiler the opportunity to inline the memcpy.
+//
+// We define this outside of nsTHashtable so only one copy exists for every N,
+// rather than separate copies for every EntryType used with nsTHashtable.
+template <size_t N>
+static void FixedSizeEntryMover(PLDHashTable*, const PLDHashEntryHdr* aFrom,
+ PLDHashEntryHdr* aTo) {
+ memcpy(aTo, aFrom, N);
+}
+
+} // namespace detail
+} // namespace mozilla
+
+//
+// template definitions
+//
+
+template <class EntryType>
+nsTHashtable<EntryType>::nsTHashtable(nsTHashtable<EntryType>&& aOther)
+ : mTable(std::move(aOther.mTable)) {}
+
+template <class EntryType>
+nsTHashtable<EntryType>& nsTHashtable<EntryType>::operator=(
+ nsTHashtable<EntryType>&& aOther) {
+ mTable = std::move(aOther.mTable);
+ return *this;
+}
+
+template <class EntryType>
+/* static */ const PLDHashTableOps* nsTHashtable<EntryType>::Ops() {
+ // If this variable is a global variable, we get strange start-up failures on
+ // WindowsCrtPatch.h (see bug 1166598 comment 20). But putting it inside a
+ // function avoids that problem.
+ static const PLDHashTableOps sOps = {
+ s_HashKey, s_MatchEntry,
+ EntryType::ALLOW_MEMMOVE
+ ? mozilla::detail::FixedSizeEntryMover<sizeof(EntryType)>
+ : s_CopyEntry,
+ // Simplify hashtable clearing in case our entries are trivially
+ // destructible.
+ std::is_trivially_destructible_v<EntryType> ? nullptr : s_ClearEntry,
+ // We don't use a generic initEntry hook because we want to allow
+ // initialization of data members defined in derived classes directly
+ // in the entry constructor (for example when a member can't be default
+ // constructed).
+ nullptr};
+ return &sOps;
+}
+
+// static definitions
+
+template <class EntryType>
+PLDHashNumber nsTHashtable<EntryType>::s_HashKey(const void* aKey) {
+ return EntryType::HashKey(static_cast<KeyTypePointer>(aKey));
+}
+
+template <class EntryType>
+bool nsTHashtable<EntryType>::s_MatchEntry(const PLDHashEntryHdr* aEntry,
+ const void* aKey) {
+ return (static_cast<const EntryType*>(aEntry))
+ ->KeyEquals(static_cast<KeyTypePointer>(aKey));
+}
+
+template <class EntryType>
+void nsTHashtable<EntryType>::s_CopyEntry(PLDHashTable* aTable,
+ const PLDHashEntryHdr* aFrom,
+ PLDHashEntryHdr* aTo) {
+ auto* fromEntry = const_cast<std::remove_const_t<EntryType>*>(
+ static_cast<const EntryType*>(aFrom));
+
+ new (mozilla::KnownNotNull, aTo) EntryType(std::move(*fromEntry));
+
+ fromEntry->~EntryType();
+}
+
+template <class EntryType>
+void nsTHashtable<EntryType>::s_ClearEntry(PLDHashTable* aTable,
+ PLDHashEntryHdr* aEntry) {
+ static_cast<EntryType*>(aEntry)->~EntryType();
+}
+
+class nsCycleCollectionTraversalCallback;
+
+template <class EntryType>
+inline void ImplCycleCollectionUnlink(nsTHashtable<EntryType>& aField) {
+ aField.Clear();
+}
+
+template <class EntryType>
+inline void ImplCycleCollectionTraverse(
+ nsCycleCollectionTraversalCallback& aCallback,
+ nsTHashtable<EntryType>& aField, const char* aName, uint32_t aFlags = 0) {
+ for (auto iter = aField.Iter(); !iter.Done(); iter.Next()) {
+ EntryType* entry = iter.Get();
+ ImplCycleCollectionTraverse(aCallback, *entry, aName, aFlags);
+ }
+}
+
+/**
+ * For nsTHashtable with pointer entries, we can have a template specialization
+ * that layers a typed T* interface on top of a common implementation that
+ * works internally with void pointers. This arrangement saves code size and
+ * might slightly improve performance as well.
+ */
+
+/**
+ * We need a separate entry type class for the inheritance structure of the
+ * nsTHashtable specialization below; nsVoidPtrHashKey is simply typedefed to a
+ * specialization of nsPtrHashKey, and the formulation:
+ *
+ * class nsTHashtable<nsPtrHashKey<T>> :
+ * protected nsTHashtable<nsPtrHashKey<const void>
+ *
+ * is not going to turn out very well, since we'd wind up with an nsTHashtable
+ * instantiation that is its own base class.
+ */
+namespace detail {
+
+class VoidPtrHashKey : public nsPtrHashKey<const void> {
+ typedef nsPtrHashKey<const void> Base;
+
+ public:
+ explicit VoidPtrHashKey(const void* aKey) : Base(aKey) {}
+};
+
+} // namespace detail
+
+/**
+ * See the main nsTHashtable documentation for descriptions of this class's
+ * methods.
+ */
+template <typename T>
+class nsTHashtable<nsPtrHashKey<T>>
+ : protected nsTHashtable<::detail::VoidPtrHashKey> {
+ typedef nsTHashtable<::detail::VoidPtrHashKey> Base;
+ typedef nsPtrHashKey<T> EntryType;
+
+ // We play games with reinterpret_cast'ing between these two classes, so
+ // try to ensure that playing said games is reasonable.
+ static_assert(sizeof(nsPtrHashKey<T>) == sizeof(::detail::VoidPtrHashKey),
+ "hash keys must be the same size");
+
+ nsTHashtable(const nsTHashtable& aOther) = delete;
+ nsTHashtable& operator=(const nsTHashtable& aOther) = delete;
+
+ public:
+ nsTHashtable() = default;
+ explicit nsTHashtable(uint32_t aInitLength) : Base(aInitLength) {}
+
+ ~nsTHashtable() = default;
+
+ nsTHashtable(nsTHashtable&&) = default;
+
+ using Base::Clear;
+ using Base::Count;
+ using Base::GetGeneration;
+ using Base::IsEmpty;
+
+ using Base::MarkImmutable;
+ using Base::ShallowSizeOfExcludingThis;
+ using Base::ShallowSizeOfIncludingThis;
+
+ /* Wrapper functions */
+ EntryType* GetEntry(T* aKey) const {
+ return reinterpret_cast<EntryType*>(Base::GetEntry(aKey));
+ }
+
+ bool Contains(T* aKey) const { return Base::Contains(aKey); }
+
+ EntryType* PutEntry(T* aKey) {
+ return reinterpret_cast<EntryType*>(Base::PutEntry(aKey));
+ }
+
+ [[nodiscard]] EntryType* PutEntry(T* aKey,
+ const mozilla::fallible_t& aFallible) {
+ return reinterpret_cast<EntryType*>(Base::PutEntry(aKey, aFallible));
+ }
+
+ [[nodiscard]] bool EnsureInserted(T* aKey, EntryType** aEntry = nullptr) {
+ return Base::EnsureInserted(
+ aKey, reinterpret_cast<::detail::VoidPtrHashKey**>(aEntry));
+ }
+
+ void RemoveEntry(T* aKey) { Base::RemoveEntry(aKey); }
+
+ bool EnsureRemoved(T* aKey) { return Base::EnsureRemoved(aKey); }
+
+ void RemoveEntry(EntryType* aEntry) {
+ Base::RemoveEntry(reinterpret_cast<::detail::VoidPtrHashKey*>(aEntry));
+ }
+
+ void RawRemoveEntry(EntryType* aEntry) {
+ Base::RawRemoveEntry(reinterpret_cast<::detail::VoidPtrHashKey*>(aEntry));
+ }
+
+ protected:
+ class EntryHandle : protected Base::EntryHandle {
+ public:
+ using Base = nsTHashtable::Base::EntryHandle;
+
+ EntryHandle(EntryHandle&& aOther) = default;
+ ~EntryHandle() = default;
+
+ EntryHandle(const EntryHandle&) = delete;
+ EntryHandle& operator=(const EntryHandle&) = delete;
+ EntryHandle& operator=(const EntryHandle&&) = delete;
+
+ using Base::Key;
+
+ using Base::HasEntry;
+
+ using Base::operator bool;
+
+ EntryType* Entry() { return reinterpret_cast<EntryType*>(Base::Entry()); }
+
+ using Base::Insert;
+
+ EntryType* OrInsert() {
+ if (!HasEntry()) {
+ Insert();
+ }
+ return Entry();
+ }
+
+ using Base::Remove;
+
+ using Base::OrRemove;
+
+ private:
+ friend class nsTHashtable;
+
+ explicit EntryHandle(Base&& aBase) : Base(std::move(aBase)) {}
+ };
+
+ template <class F>
+ auto WithEntryHandle(KeyType aKey, F aFunc)
+ -> std::invoke_result_t<F, EntryHandle&&> {
+ return Base::WithEntryHandle(aKey, [&aFunc](auto entryHandle) {
+ return aFunc(EntryHandle{std::move(entryHandle)});
+ });
+ }
+
+ template <class F>
+ auto WithEntryHandle(KeyType aKey, const mozilla::fallible_t& aFallible,
+ F aFunc)
+ -> std::invoke_result_t<F, mozilla::Maybe<EntryHandle>&&> {
+ return Base::WithEntryHandle(
+ aKey, aFallible, [&aFunc](auto maybeEntryHandle) {
+ return aFunc(maybeEntryHandle ? mozilla::Some(EntryHandle{
+ maybeEntryHandle.extract()})
+ : mozilla::Nothing());
+ });
+ }
+
+ public:
+ class ConstIterator {
+ public:
+ explicit ConstIterator(nsTHashtable* aTable)
+ : mBaseIterator(&aTable->mTable) {}
+ ~ConstIterator() = default;
+
+ KeyType Key() const { return Get()->GetKey(); }
+
+ const EntryType* Get() const {
+ return static_cast<const EntryType*>(mBaseIterator.Get());
+ }
+
+ bool Done() const { return mBaseIterator.Done(); }
+ void Next() { mBaseIterator.Next(); }
+
+ ConstIterator() = delete;
+ ConstIterator(const ConstIterator&) = delete;
+ ConstIterator(ConstIterator&& aOther) = delete;
+ ConstIterator& operator=(const ConstIterator&) = delete;
+ ConstIterator& operator=(ConstIterator&&) = delete;
+
+ protected:
+ PLDHashTable::Iterator mBaseIterator;
+ };
+
+ class Iterator final : public ConstIterator {
+ public:
+ using ConstIterator::ConstIterator;
+
+ using ConstIterator::Get;
+
+ EntryType* Get() const {
+ return static_cast<EntryType*>(this->mBaseIterator.Get());
+ }
+
+ void Remove() { this->mBaseIterator.Remove(); }
+ };
+
+ Iterator Iter() { return Iterator(this); }
+
+ ConstIterator ConstIter() const {
+ return ConstIterator(const_cast<nsTHashtable*>(this));
+ }
+
+ using const_iterator = ::detail::nsTHashtableEntryIterator<const EntryType>;
+ using iterator = ::detail::nsTHashtableEntryIterator<EntryType>;
+
+ iterator begin() { return iterator{mTable}; }
+ const_iterator begin() const { return const_iterator{mTable}; }
+ const_iterator cbegin() const { return begin(); }
+ iterator end() {
+ return iterator{mTable, typename iterator::EndIteratorTag{}};
+ }
+ const_iterator end() const {
+ return const_iterator{mTable, typename const_iterator::EndIteratorTag{}};
+ }
+ const_iterator cend() const { return end(); }
+
+ auto Keys() const {
+ return ::detail::nsTHashtableKeyRange<nsPtrHashKey<T>>{mTable};
+ }
+
+ void Remove(::detail::nsTHashtableKeyIterator<EntryType>& aIter) {
+ aIter.mIterator.Remove();
+ }
+
+ void SwapElements(nsTHashtable& aOther) { Base::SwapElements(aOther); }
+};
+
+#endif // nsTHashtable_h__
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 18:08:54 +0000