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Diffstat (limited to 'js/xpconnect/src/XPCJSID.cpp')
| -rw-r--r-- | js/xpconnect/src/XPCJSID.cpp | 626 |
1 files changed, 626 insertions, 0 deletions
diff --git a/js/xpconnect/src/XPCJSID.cpp b/js/xpconnect/src/XPCJSID.cpp new file mode 100644 index 0000000000..565dc99c86 --- /dev/null +++ b/js/xpconnect/src/XPCJSID.cpp @@ -0,0 +1,626 @@ +/* -*- 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/. */ + +/* An xpcom implementation of the JavaScript nsIID and nsCID objects. */ + +#include "xpcprivate.h" +#include "mozilla/dom/BindingUtils.h" +#include "mozilla/Attributes.h" +#include "js/Object.h" // JS::GetClass, JS::GetReservedSlot +#include "js/PropertyAndElement.h" // JS_DefineFunction, JS_DefineFunctionById, JS_DefineProperty, JS_DefinePropertyById +#include "js/Symbol.h" +#include "nsContentUtils.h" + +using namespace mozilla; +using namespace mozilla::dom; +using namespace JS; + +namespace xpc { + +/****************************************************************************** + * # Generic IDs # + * + * Generic IDs are the type of JS object created by most code which passes nsID + * objects to JavaScript code. They provide no special methods, and only store + * the raw nsID value. + * + * The nsID value is stored in 4 reserved slots, with 32 bits of the 128-bit + * value stored in each slot. Getter code extracts this data, and combines them + * back into the nsID value. + */ +static bool ID_Equals(JSContext* aCx, unsigned aArgc, Value* aVp); +static bool ID_GetNumber(JSContext* aCx, unsigned aArgc, Value* aVp); + +// Generic ID objects contain 4 reserved slots, each containing a uint32_t with +// 1/4 of the representation of the nsID value. This allows us to avoid an extra +// allocation for the nsID object, and eliminates the need for a finalizer. +enum { kID_Slot0, kID_Slot1, kID_Slot2, kID_Slot3, kID_SlotCount }; +static const JSClass sID_Class = { + "nsJSID", JSCLASS_HAS_RESERVED_SLOTS(kID_SlotCount), JS_NULL_CLASS_OPS}; + +/****************************************************************************** + * # Interface IDs # + * + * In addition to the properties exposed by Generic ID objects, IID supports + * 'instanceof', exposes constant properties defined on the class, and exposes + * the interface name as the 'name' and 'toString()' values. + */ +static bool IID_HasInstance(JSContext* aCx, unsigned aArgc, Value* aVp); +static bool IID_GetName(JSContext* aCx, unsigned aArgc, Value* aVp); + +static bool IID_NewEnumerate(JSContext* cx, HandleObject obj, + MutableHandleIdVector properties, + bool enumerableOnly); +static bool IID_Resolve(JSContext* cx, HandleObject obj, HandleId id, + bool* resolvedp); +static bool IID_MayResolve(const JSAtomState& names, jsid id, + JSObject* maybeObj); + +static const JSClassOps sIID_ClassOps = { + nullptr, // addProperty + nullptr, // delProperty + nullptr, // enumerate + IID_NewEnumerate, // newEnumerate + IID_Resolve, // resolve + IID_MayResolve, // mayResolve + nullptr, // finalize + nullptr, // call + nullptr, // construct + nullptr, // trace +}; + +// Interface ID objects use a single reserved slot containing a pointer to the +// nsXPTInterfaceInfo object for the interface in question. +enum { kIID_InfoSlot, kIID_SlotCount }; +static const JSClass sIID_Class = { + "nsJSIID", JSCLASS_HAS_RESERVED_SLOTS(kIID_SlotCount), &sIID_ClassOps}; + +/****************************************************************************** + * # Contract IDs # + * + * In addition to the properties exposed by Generic ID objects, Contract IDs + * expose 'getService' and 'createInstance' methods, and expose the contractID + * string as '.name' and '.toString()'. + */ +static bool CID_CreateInstance(JSContext* aCx, unsigned aArgc, Value* aVp); +static bool CID_GetService(JSContext* aCx, unsigned aArgc, Value* aVp); +static bool CID_GetName(JSContext* aCx, unsigned aArgc, Value* aVp); + +// ContractID objects use a single reserved slot, containing the ContractID. The +// nsCID value for this object is looked up when the object is being unwrapped. +enum { kCID_ContractSlot, kCID_SlotCount }; +static const JSClass sCID_Class = { + "nsJSCID", JSCLASS_HAS_RESERVED_SLOTS(kCID_SlotCount), JS_NULL_CLASS_OPS}; + +/** + * Ensure that the nsID prototype objects have been created for the current + * global, and extract the prototype values. + */ +static JSObject* GetIDPrototype(JSContext* aCx, const JSClass* aClass) { + XPCWrappedNativeScope* scope = ObjectScope(CurrentGlobalOrNull(aCx)); + if (NS_WARN_IF(!scope)) { + return nullptr; + } + + // Create prototype objects for the JSID objects if they haven't been + // created for this scope yet. + if (!scope->mIDProto) { + MOZ_ASSERT(!scope->mIIDProto && !scope->mCIDProto); + + RootedObject idProto(aCx, JS_NewPlainObject(aCx)); + RootedObject iidProto(aCx, + JS_NewObjectWithGivenProto(aCx, nullptr, idProto)); + RootedObject cidProto(aCx, + JS_NewObjectWithGivenProto(aCx, nullptr, idProto)); + RootedId hasInstance(aCx, + GetWellKnownSymbolKey(aCx, SymbolCode::hasInstance)); + + const uint32_t kFlags = + JSPROP_READONLY | JSPROP_ENUMERATE | JSPROP_PERMANENT; + const uint32_t kNoEnum = JSPROP_READONLY | JSPROP_PERMANENT; + + bool ok = + idProto && iidProto && cidProto && + // Methods and properties on all ID Objects: + JS_DefineFunction(aCx, idProto, "equals", ID_Equals, 1, kFlags) && + JS_DefineProperty(aCx, idProto, "number", ID_GetNumber, nullptr, + kFlags) && + + // Methods for IfaceID objects, which also inherit ID properties: + JS_DefineFunctionById(aCx, iidProto, hasInstance, IID_HasInstance, 1, + kNoEnum) && + JS_DefineProperty(aCx, iidProto, "name", IID_GetName, nullptr, + kFlags) && + + // Methods for ContractID objects, which also inherit ID properties: + JS_DefineFunction(aCx, cidProto, "createInstance", CID_CreateInstance, + 1, kFlags) && + JS_DefineFunction(aCx, cidProto, "getService", CID_GetService, 1, + kFlags) && + JS_DefineProperty(aCx, cidProto, "name", CID_GetName, nullptr, + kFlags) && + + // ToString returns '.number' on generic IDs, while returning + // '.name' on other ID types. + JS_DefineFunction(aCx, idProto, "toString", ID_GetNumber, 0, kFlags) && + JS_DefineFunction(aCx, iidProto, "toString", IID_GetName, 0, kFlags) && + JS_DefineFunction(aCx, cidProto, "toString", CID_GetName, 0, kFlags); + if (!ok) { + return nullptr; + } + + scope->mIDProto = idProto; + scope->mIIDProto = iidProto; + scope->mCIDProto = cidProto; + } + + if (aClass == &sID_Class) { + return scope->mIDProto; + } else if (aClass == &sIID_Class) { + return scope->mIIDProto; + } else if (aClass == &sCID_Class) { + return scope->mCIDProto; + } + + MOZ_CRASH("Unrecognized ID Object Class"); +} + +// Unwrap the given value to an object with the correct class, or nullptr. +static JSObject* GetIDObject(HandleValue aVal, const JSClass* aClass) { + if (aVal.isObject()) { + // We care only about IID/CID objects here, so CheckedUnwrapStatic is fine. + JSObject* obj = js::CheckedUnwrapStatic(&aVal.toObject()); + if (obj && JS::GetClass(obj) == aClass) { + return obj; + } + } + return nullptr; +} + +static const nsXPTInterfaceInfo* GetInterfaceInfo(JSObject* obj) { + MOZ_ASSERT(JS::GetClass(obj) == &sIID_Class); + return static_cast<const nsXPTInterfaceInfo*>( + JS::GetReservedSlot(obj, kIID_InfoSlot).toPrivate()); +} + +/** + * Unwrap an nsID object from a JSValue. + * + * For Generic ID objects, this function will extract the nsID from reserved + * slots. For IfaceID objects, it will be extracted from the nsXPTInterfaceInfo, + * and for ContractID objects, the ContractID's corresponding CID will be looked + * up. + */ +Maybe<nsID> JSValue2ID(JSContext* aCx, HandleValue aVal) { + if (!aVal.isObject()) { + return Nothing(); + } + + // We only care about ID objects here, so CheckedUnwrapStatic is fine. + RootedObject obj(aCx, js::CheckedUnwrapStatic(&aVal.toObject())); + if (!obj) { + return Nothing(); + } + + mozilla::Maybe<nsID> id; + if (JS::GetClass(obj) == &sID_Class) { + // Extract the raw bytes of the nsID from reserved slots. + uint32_t rawid[] = {JS::GetReservedSlot(obj, kID_Slot0).toPrivateUint32(), + JS::GetReservedSlot(obj, kID_Slot1).toPrivateUint32(), + JS::GetReservedSlot(obj, kID_Slot2).toPrivateUint32(), + JS::GetReservedSlot(obj, kID_Slot3).toPrivateUint32()}; + + // Construct a nsID inside the Maybe, and copy the rawid into it. + id.emplace(); + memcpy(id.ptr(), &rawid, sizeof(nsID)); + } else if (JS::GetClass(obj) == &sIID_Class) { + // IfaceID objects store a nsXPTInterfaceInfo* pointer. + const nsXPTInterfaceInfo* info = GetInterfaceInfo(obj); + id.emplace(info->IID()); + } else if (JS::GetClass(obj) == &sCID_Class) { + // ContractID objects store a ContractID string. + JS::UniqueChars contractId = JS_EncodeStringToLatin1( + aCx, JS::GetReservedSlot(obj, kCID_ContractSlot).toString()); + + // NOTE(nika): If we directly access the nsComponentManager, we can do + // this with a more-basic pointer lookup: + // nsFactoryEntry* entry = nsComponentManagerImpl::gComponentManager-> + // GetFactoryEntry(contractId.ptr(), contractId.length()); + // if (entry) id.emplace(entry->mCIDEntry->cid); + + nsCOMPtr<nsIComponentRegistrar> registrar; + nsresult rv = NS_GetComponentRegistrar(getter_AddRefs(registrar)); + if (NS_FAILED(rv) || !registrar) { + return Nothing(); + } + + nsCID* cid = nullptr; + if (NS_SUCCEEDED(registrar->ContractIDToCID(contractId.get(), &cid))) { + id.emplace(*cid); + free(cid); + } + } + return id; +} + +/** + * Public ID Object Constructor Methods + */ +static JSObject* NewIDObjectHelper(JSContext* aCx, const JSClass* aClass) { + RootedObject proto(aCx, GetIDPrototype(aCx, aClass)); + if (proto) { + return JS_NewObjectWithGivenProto(aCx, aClass, proto); + } + return nullptr; +} + +bool ID2JSValue(JSContext* aCx, const nsID& aId, MutableHandleValue aVal) { + RootedObject obj(aCx, NewIDObjectHelper(aCx, &sID_Class)); + if (!obj) { + return false; + } + + // Get the data in nsID as 4 uint32_ts, and store them in slots. + uint32_t rawid[4]; + memcpy(&rawid, &aId, sizeof(nsID)); + static_assert(sizeof(nsID) == sizeof(rawid), "Wrong size of nsID"); + JS::SetReservedSlot(obj, kID_Slot0, PrivateUint32Value(rawid[0])); + JS::SetReservedSlot(obj, kID_Slot1, PrivateUint32Value(rawid[1])); + JS::SetReservedSlot(obj, kID_Slot2, PrivateUint32Value(rawid[2])); + JS::SetReservedSlot(obj, kID_Slot3, PrivateUint32Value(rawid[3])); + + aVal.setObject(*obj); + return true; +} + +bool IfaceID2JSValue(JSContext* aCx, const nsXPTInterfaceInfo& aInfo, + MutableHandleValue aVal) { + RootedObject obj(aCx, NewIDObjectHelper(aCx, &sIID_Class)); + if (!obj) { + return false; + } + + // The InterfaceInfo is stored in a reserved slot. + JS::SetReservedSlot(obj, kIID_InfoSlot, PrivateValue((void*)&aInfo)); + aVal.setObject(*obj); + return true; +} + +bool ContractID2JSValue(JSContext* aCx, JSString* aContract, + MutableHandleValue aVal) { + RootedString jsContract(aCx, aContract); + + { + // It is perfectly safe to have a ContractID object with an invalid + // ContractID, but is usually a bug. + nsCOMPtr<nsIComponentRegistrar> registrar; + NS_GetComponentRegistrar(getter_AddRefs(registrar)); + if (!registrar) { + return false; + } + + bool registered = false; + JS::UniqueChars contract = JS_EncodeStringToLatin1(aCx, jsContract); + registrar->IsContractIDRegistered(contract.get(), ®istered); + if (!registered) { + return false; + } + } + + RootedObject obj(aCx, NewIDObjectHelper(aCx, &sCID_Class)); + if (!obj) { + return false; + } + + // The Contract is stored in a reserved slot. + JS::SetReservedSlot(obj, kCID_ContractSlot, StringValue(jsContract)); + aVal.setObject(*obj); + return true; +} + +/****************************************************************************** + * # Method & Property Getter Implementations # + */ + +// NOTE: This method is used both for 'get ID.prototype.number' and +// 'ID.prototype.toString'. +static bool ID_GetNumber(JSContext* aCx, unsigned aArgc, Value* aVp) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + + Maybe<nsID> id = JSValue2ID(aCx, args.thisv()); + if (!id) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + char buf[NSID_LENGTH]; + id->ToProvidedString(buf); + JSString* jsnum = JS_NewStringCopyZ(aCx, buf); + if (!jsnum) { + return Throw(aCx, NS_ERROR_OUT_OF_MEMORY); + } + + args.rval().setString(jsnum); + return true; +} + +static bool ID_Equals(JSContext* aCx, unsigned aArgc, Value* aVp) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + if (!args.requireAtLeast(aCx, "nsID.equals", 1)) { + return false; + } + + Maybe<nsID> id = JSValue2ID(aCx, args.thisv()); + Maybe<nsID> id2 = JSValue2ID(aCx, args[0]); + if (!id || !id2) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + args.rval().setBoolean(id->Equals(*id2)); + return true; +} + +/* + * HasInstance hooks need to find an appropriate reflector in order to function + * properly. There are two complexities that we need to handle: + * + * 1 - Cross-compartment wrappers. Chrome uses over 100 compartments, all with + * system principal. The success of an instanceof check should not depend + * on which compartment an object comes from. At the same time, we want to + * make sure we don't unwrap important security wrappers. + * CheckedUnwrap does the right thing here. + * + * 2 - Prototype chains. Suppose someone creates a vanilla JS object |a| and + * sets its __proto__ to some WN |b|. If |b instanceof nsIFoo| returns true, + * one would expect |a instanceof nsIFoo| to return true as well, since + * instanceof is transitive up the prototype chain in ECMAScript. Moreover, + * there's chrome code that relies on this. + * + * This static method handles both complexities, returning either an XPCWN, a + * DOM object, or null. The object may well be cross-compartment from |cx|. + */ +static nsresult FindObjectForHasInstance(JSContext* cx, HandleObject objArg, + MutableHandleObject target) { + RootedObject obj(cx, objArg), proto(cx); + while (true) { + // Try the object, or the wrappee if allowed. We want CheckedUnwrapDynamic + // here, because we might in fact be looking for a Window. "cx" represents + // our current global. + JSObject* o = + js::IsWrapper(obj) ? js::CheckedUnwrapDynamic(obj, cx, false) : obj; + if (o && (IsWrappedNativeReflector(o) || IsDOMObject(o))) { + target.set(o); + return NS_OK; + } + + // Walk the prototype chain from the perspective of the callee (i.e. + // respecting Xrays if they exist). + if (!js::GetObjectProto(cx, obj, &proto)) { + return NS_ERROR_FAILURE; + } + if (!proto) { + target.set(nullptr); + return NS_OK; + } + obj = proto; + } +} + +nsresult HasInstance(JSContext* cx, HandleObject objArg, const nsID* iid, + bool* bp) { + *bp = false; + + RootedObject obj(cx); + nsresult rv = FindObjectForHasInstance(cx, objArg, &obj); + if (NS_WARN_IF(NS_FAILED(rv))) { + return rv; + } + + if (!obj) { + return NS_OK; + } + + // Need to unwrap Window correctly here, so use ReflectorToISupportsDynamic. + nsCOMPtr<nsISupports> identity = ReflectorToISupportsDynamic(obj, cx); + if (!identity) { + return NS_OK; + } + + nsCOMPtr<nsISupports> supp; + identity->QueryInterface(*iid, getter_AddRefs(supp)); + *bp = supp; + + // Our old HasInstance implementation operated by invoking FindTearOff on + // XPCWrappedNatives, and various bits of chrome JS came to depend on + // |instanceof| doing an implicit QI if it succeeds. Do a drive-by QI to + // preserve that behavior. This is just a compatibility hack, so we don't + // really care if it fails. + if (IsWrappedNativeReflector(obj)) { + (void)XPCWrappedNative::Get(obj)->FindTearOff(cx, *iid); + } + + return NS_OK; +} + +static bool IID_HasInstance(JSContext* aCx, unsigned aArgc, Value* aVp) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + if (!args.requireAtLeast(aCx, "nsIID[Symbol.hasInstance]", 1)) { + return false; + } + + Maybe<nsID> id = JSValue2ID(aCx, args.thisv()); + if (!id) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + bool hasInstance = false; + if (args[0].isObject()) { + RootedObject target(aCx, &args[0].toObject()); + nsresult rv = HasInstance(aCx, target, id.ptr(), &hasInstance); + if (NS_FAILED(rv)) { + return Throw(aCx, rv); + } + } + args.rval().setBoolean(hasInstance); + return true; +} + +// NOTE: This method is used both for 'get IID.prototype.name' and +// 'IID.prototype.toString'. +static bool IID_GetName(JSContext* aCx, unsigned aArgc, Value* aVp) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + + RootedObject obj(aCx, GetIDObject(args.thisv(), &sIID_Class)); + if (!obj) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + const nsXPTInterfaceInfo* info = GetInterfaceInfo(obj); + + // Name property is the name of the interface this nsIID was created from. + JSString* name = JS_NewStringCopyZ(aCx, info->Name()); + if (!name) { + return Throw(aCx, NS_ERROR_OUT_OF_MEMORY); + } + + args.rval().setString(name); + return true; +} + +static bool IID_NewEnumerate(JSContext* cx, HandleObject obj, + MutableHandleIdVector properties, + bool enumerableOnly) { + const nsXPTInterfaceInfo* info = GetInterfaceInfo(obj); + + if (!properties.reserve(info->ConstantCount())) { + JS_ReportOutOfMemory(cx); + return false; + } + + RootedId id(cx); + RootedString name(cx); + for (uint16_t i = 0; i < info->ConstantCount(); ++i) { + name = JS_AtomizeString(cx, info->Constant(i).Name()); + if (!name || !JS_StringToId(cx, name, &id)) { + return false; + } + properties.infallibleAppend(id); + } + + return true; +} + +static bool IID_Resolve(JSContext* cx, HandleObject obj, HandleId id, + bool* resolvedp) { + *resolvedp = false; + if (!id.isString()) { + return true; + } + + JSLinearString* name = id.toLinearString(); + const nsXPTInterfaceInfo* info = GetInterfaceInfo(obj); + for (uint16_t i = 0; i < info->ConstantCount(); ++i) { + if (JS_LinearStringEqualsAscii(name, info->Constant(i).Name())) { + *resolvedp = true; + + RootedValue constant(cx, info->Constant(i).JSValue()); + return JS_DefinePropertyById( + cx, obj, id, constant, + JSPROP_READONLY | JSPROP_ENUMERATE | JSPROP_PERMANENT); + } + } + return true; +} + +static bool IID_MayResolve(const JSAtomState& names, jsid id, + JSObject* maybeObj) { + if (!id.isString()) { + return false; + } + + if (!maybeObj) { + // Each interface object has its own set of constants, so if we don't know + // the object, assume any string property may be resolved. + return true; + } + + JSLinearString* name = id.toLinearString(); + const nsXPTInterfaceInfo* info = GetInterfaceInfo(maybeObj); + for (uint16_t i = 0; i < info->ConstantCount(); ++i) { + if (JS_LinearStringEqualsAscii(name, info->Constant(i).Name())) { + return true; + } + } + return false; +} + +// Common code for CID_CreateInstance and CID_GetService +static bool CIGSHelper(JSContext* aCx, unsigned aArgc, Value* aVp, + bool aGetService) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + + // Extract the ContractID string from our reserved slot. Don't use + // JSValue2ID as this method should only be defined on Contract ID objects, + // and it allows us to avoid a duplicate hashtable lookup. + RootedObject obj(aCx, GetIDObject(args.thisv(), &sCID_Class)); + if (!obj) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + JS::UniqueChars contractID = JS_EncodeStringToLatin1( + aCx, JS::GetReservedSlot(obj, kCID_ContractSlot).toString()); + + // Extract the IID from the first argument, if passed. Default: nsISupports. + Maybe<nsIID> iid = args.length() >= 1 ? JSValue2ID(aCx, args[0]) + : Some(NS_GET_IID(nsISupports)); + if (!iid) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + // Invoke CreateInstance or GetService with our ContractID. + nsresult rv; + nsCOMPtr<nsISupports> result; + if (aGetService) { + rv = CallGetService(contractID.get(), *iid, getter_AddRefs(result)); + if (NS_FAILED(rv) || !result) { + return Throw(aCx, NS_ERROR_XPC_GS_RETURNED_FAILURE); + } + } else { + rv = CallCreateInstance(contractID.get(), *iid, getter_AddRefs(result)); + if (NS_FAILED(rv) || !result) { + return Throw(aCx, NS_ERROR_XPC_CI_RETURNED_FAILURE); + } + } + + // Wrap the created object and return it. + rv = nsContentUtils::WrapNative(aCx, result, iid.ptr(), args.rval()); + if (NS_FAILED(rv) || args.rval().isPrimitive()) { + return Throw(aCx, NS_ERROR_XPC_CANT_CREATE_WN); + } + return true; +} + +static bool CID_CreateInstance(JSContext* aCx, unsigned aArgc, Value* aVp) { + return CIGSHelper(aCx, aArgc, aVp, /* aGetService = */ false); +} + +static bool CID_GetService(JSContext* aCx, unsigned aArgc, Value* aVp) { + return CIGSHelper(aCx, aArgc, aVp, /* aGetService = */ true); +} + +// NOTE: This method is used both for 'get CID.prototype.name' and +// 'CID.prototype.toString'. +static bool CID_GetName(JSContext* aCx, unsigned aArgc, Value* aVp) { + CallArgs args = CallArgsFromVp(aArgc, aVp); + RootedObject obj(aCx, GetIDObject(args.thisv(), &sCID_Class)); + if (!obj) { + return Throw(aCx, NS_ERROR_XPC_BAD_CONVERT_JS); + } + + // Return the string stored in our reserved ContractID slot. + args.rval().set(JS::GetReservedSlot(obj, kCID_ContractSlot)); + return true; +} + +} // namespace xpc |