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Diffstat (limited to 'js/src/vm/Realm.cpp')
| -rw-r--r-- | js/src/vm/Realm.cpp | 783 |
1 files changed, 783 insertions, 0 deletions
diff --git a/js/src/vm/Realm.cpp b/js/src/vm/Realm.cpp new file mode 100644 index 0000000000..2eadfe2c85 --- /dev/null +++ b/js/src/vm/Realm.cpp @@ -0,0 +1,783 @@ +/* -*- 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/. */ + +#include "js/shadow/Realm.h" // JS::shadow::Realm +#include "vm/Realm-inl.h" + +#include "mozilla/MemoryReporting.h" + +#include <stddef.h> + +#include "jsfriendapi.h" + +#include "builtin/WrappedFunctionObject.h" +#include "debugger/DebugAPI.h" +#include "debugger/Debugger.h" +#include "gc/GC.h" +#include "jit/JitRealm.h" +#include "jit/JitRuntime.h" +#include "js/CallAndConstruct.h" // JS::IsCallable +#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_* +#include "js/GCVariant.h" +#include "js/Proxy.h" +#include "js/RootingAPI.h" +#include "js/Wrapper.h" +#include "vm/Compartment.h" +#include "vm/DateTime.h" +#include "vm/Iteration.h" +#include "vm/JSContext.h" +#include "vm/PIC.h" + +#include "gc/Marking-inl.h" +#include "vm/JSObject-inl.h" + +using namespace js; + +Realm::DebuggerVectorEntry::DebuggerVectorEntry(js::Debugger* dbg_, + JSObject* link) + : dbg(dbg_), debuggerLink(link) {} + +ObjectRealm::ObjectRealm(JS::Zone* zone) + : innerViews(zone, zone), iteratorCache(zone) {} + +Realm::Realm(Compartment* comp, const JS::RealmOptions& options) + : JS::shadow::Realm(comp), + zone_(comp->zone()), + runtime_(comp->runtimeFromMainThread()), + creationOptions_(options.creationOptions()), + behaviors_(options.behaviors()), + objects_(zone_), + randomKeyGenerator_(runtime_->forkRandomKeyGenerator()), + debuggers_(zone_), + allocatedDuringIncrementalGC_(zone_->isGCMarkingOrSweeping() || + zone_->isGCFinished()), + wasm(runtime_) { + runtime_->numRealms++; +} + +Realm::~Realm() { + MOZ_ASSERT(!hasBeenEnteredIgnoringJit()); + MOZ_ASSERT(!isDebuggee()); + + // Write the code coverage information in a file. + if (lcovRealm_) { + runtime_->lcovOutput().writeLCovResult(*lcovRealm_); + } + + MOZ_ASSERT(runtime_->numRealms > 0); + runtime_->numRealms--; +} + +void Realm::init(JSContext* cx, JSPrincipals* principals) { + /* + * As a hack, we clear our timezone cache every time we create a new realm. + * This ensures that the cache is always relatively fresh, but shouldn't + * interfere with benchmarks that create tons of date objects (unless they + * also create tons of iframes, which seems unlikely). + */ + js::ResetTimeZoneInternal(ResetTimeZoneMode::DontResetIfOffsetUnchanged); + + if (principals) { + // Any realm with the trusted principals -- and there can be + // multiple -- is a system realm. + isSystem_ = (principals == cx->runtime()->trustedPrincipals()); + JS_HoldPrincipals(principals); + principals_ = principals; + } +} + +bool JSRuntime::createJitRuntime(JSContext* cx) { + using namespace js::jit; + + MOZ_ASSERT(!jitRuntime_); + + if (!CanLikelyAllocateMoreExecutableMemory()) { + // Try to release memory first instead of potentially reporting OOM below. + if (OnLargeAllocationFailure) { + OnLargeAllocationFailure(); + } + } + + jit::JitRuntime* jrt = cx->new_<jit::JitRuntime>(); + if (!jrt) { + return false; + } + + // Unfortunately, initialization depends on jitRuntime_ being non-null, so + // we can't just wait to assign jitRuntime_. + jitRuntime_ = jrt; + + if (!jitRuntime_->initialize(cx)) { + js_delete(jitRuntime_.ref()); + jitRuntime_ = nullptr; + return false; + } + + return true; +} + +bool Realm::ensureJitRealmExists(JSContext* cx) { + using namespace js::jit; + + if (jitRealm_) { + return true; + } + + if (!zone()->getJitZone(cx)) { + return false; + } + + UniquePtr<JitRealm> jitRealm = cx->make_unique<JitRealm>(); + if (!jitRealm) { + return false; + } + + jitRealm->initialize(zone()->allocNurseryStrings); + + jitRealm_ = std::move(jitRealm); + return true; +} + +#ifdef JSGC_HASH_TABLE_CHECKS + +void js::DtoaCache::checkCacheAfterMovingGC() { + MOZ_ASSERT(!str || !IsForwarded(str)); +} + +#endif // JSGC_HASH_TABLE_CHECKS + +NonSyntacticLexicalEnvironmentObject* +ObjectRealm::getOrCreateNonSyntacticLexicalEnvironment(JSContext* cx, + HandleObject enclosing, + HandleObject key, + HandleObject thisv) { + MOZ_ASSERT(&ObjectRealm::get(enclosing) == this); + + if (!nonSyntacticLexicalEnvironments_) { + auto map = cx->make_unique<ObjectWeakMap>(cx); + if (!map) { + return nullptr; + } + + nonSyntacticLexicalEnvironments_ = std::move(map); + } + + RootedObject lexicalEnv(cx, nonSyntacticLexicalEnvironments_->lookup(key)); + + if (!lexicalEnv) { + MOZ_ASSERT(key->is<NonSyntacticVariablesObject>() || + !key->is<EnvironmentObject>()); + lexicalEnv = + NonSyntacticLexicalEnvironmentObject::create(cx, enclosing, thisv); + if (!lexicalEnv) { + return nullptr; + } + if (!nonSyntacticLexicalEnvironments_->add(cx, key, lexicalEnv)) { + return nullptr; + } + } + + return &lexicalEnv->as<NonSyntacticLexicalEnvironmentObject>(); +} + +NonSyntacticLexicalEnvironmentObject* +ObjectRealm::getOrCreateNonSyntacticLexicalEnvironment(JSContext* cx, + HandleObject enclosing) { + // If a wrapped WithEnvironmentObject was passed in, unwrap it, as we may + // be creating different WithEnvironmentObject wrappers each time. + RootedObject key(cx, enclosing); + if (enclosing->is<WithEnvironmentObject>()) { + MOZ_ASSERT(!enclosing->as<WithEnvironmentObject>().isSyntactic()); + key = &enclosing->as<WithEnvironmentObject>().object(); + } + + // NOTE: The default global |this| value is set to key for compatibility + // with existing users of the lexical environment cache. + // - When used by shared-global JSM loader, |this| must be the + // NonSyntacticVariablesObject passed as enclosing. + // - When used by SubscriptLoader, |this| must be the target object of + // the WithEnvironmentObject wrapper. + // - When used by XBL/DOM Events, we execute directly as a function and + // do not access the |this| value. + // See js::GetFunctionThis / js::GetNonSyntacticGlobalThis + return getOrCreateNonSyntacticLexicalEnvironment(cx, enclosing, key, + /*thisv = */ key); +} + +NonSyntacticLexicalEnvironmentObject* +ObjectRealm::getNonSyntacticLexicalEnvironment(JSObject* key) const { + MOZ_ASSERT(&ObjectRealm::get(key) == this); + + if (!nonSyntacticLexicalEnvironments_) { + return nullptr; + } + // If a wrapped WithEnvironmentObject was passed in, unwrap it as in + // getOrCreateNonSyntacticLexicalEnvironment. + if (key->is<WithEnvironmentObject>()) { + MOZ_ASSERT(!key->as<WithEnvironmentObject>().isSyntactic()); + key = &key->as<WithEnvironmentObject>().object(); + } + JSObject* lexicalEnv = nonSyntacticLexicalEnvironments_->lookup(key); + if (!lexicalEnv) { + return nullptr; + } + return &lexicalEnv->as<NonSyntacticLexicalEnvironmentObject>(); +} + +void Realm::traceGlobalData(JSTracer* trc) { + // Trace things reachable from the realm's global. Note that these edges + // must be swept too in case the realm is live but the global is not. + + savedStacks_.trace(trc); + + DebugAPI::traceFromRealm(trc, this); +} + +void ObjectRealm::trace(JSTracer* trc) { + if (objectMetadataTable) { + objectMetadataTable->trace(trc); + } + + if (nonSyntacticLexicalEnvironments_) { + nonSyntacticLexicalEnvironments_->trace(trc); + } +} + +void Realm::traceRoots(JSTracer* trc, + js::gc::GCRuntime::TraceOrMarkRuntime traceOrMark) { + if (objectMetadataState_.is<PendingMetadata>()) { + GCPolicy<NewObjectMetadataState>::trace(trc, &objectMetadataState_, + "on-stack object pending metadata"); + } + + if (!JS::RuntimeHeapIsMinorCollecting()) { + // The global is never nursery allocated, so we don't need to + // trace it when doing a minor collection. + // + // If a realm is on-stack, we mark its global so that + // JSContext::global() remains valid. + if (shouldTraceGlobal() && global_) { + TraceRoot(trc, global_.unbarrieredAddress(), "on-stack realm global"); + } + } + + // Nothing below here needs to be treated as a root if we aren't marking + // this zone for a collection. + if (traceOrMark == js::gc::GCRuntime::MarkRuntime && + !zone()->isCollectingFromAnyThread()) { + return; + } + + /* Mark debug scopes, if present */ + if (debugEnvs_) { + debugEnvs_->trace(trc); + } + + objects_.trace(trc); +} + +void ObjectRealm::finishRoots() { + if (objectMetadataTable) { + objectMetadataTable->clear(); + } + + if (nonSyntacticLexicalEnvironments_) { + nonSyntacticLexicalEnvironments_->clear(); + } +} + +void Realm::finishRoots() { + if (debugEnvs_) { + debugEnvs_->finish(); + } + + objects_.finishRoots(); +} + +void ObjectRealm::sweepAfterMinorGC(JSTracer* trc) { + InnerViewTable& table = innerViews.get(); + if (table.needsSweepAfterMinorGC()) { + table.sweepAfterMinorGC(trc); + } +} + +void Realm::sweepAfterMinorGC(JSTracer* trc) { + globalWriteBarriered = 0; + dtoaCache.purge(); + objects_.sweepAfterMinorGC(trc); +} + +void Realm::traceWeakSavedStacks(JSTracer* trc) { savedStacks_.traceWeak(trc); } + +void Realm::traceWeakGlobalEdge(JSTracer* trc) { + // If the global is dead, free its GlobalObjectData. + auto result = TraceWeakEdge(trc, &global_, "Realm::global_"); + if (result.isDead()) { + result.initialTarget()->releaseData(runtime_->gcContext()); + } +} + +void Realm::traceWeakEdgesInJitRealm(JSTracer* trc) { + if (jitRealm_) { + jitRealm_->traceWeak(trc, this); + } +} + +void Realm::traceWeakRegExps(JSTracer* trc) { + /* + * JIT code increments activeWarmUpCounter for any RegExpShared used by jit + * code for the lifetime of the JIT script. Thus, we must perform + * sweeping after clearing jit code. + */ + regExps.traceWeak(trc); +} + +void Realm::traceWeakDebugEnvironmentEdges(JSTracer* trc) { + if (debugEnvs_) { + debugEnvs_->traceWeak(trc); + } +} + +void Realm::fixupAfterMovingGC(JSTracer* trc) { + purge(); + traceWeakGlobalEdge(trc); +} + +void Realm::purge() { + dtoaCache.purge(); + newProxyCache.purge(); + newPlainObjectWithPropsCache.purge(); + objects_.iteratorCache.clearAndCompact(); + arraySpeciesLookup.purge(); + promiseLookup.purge(); + + if (zone()->isGCPreparing()) { + purgeForOfPicChain(); + } +} + +void Realm::purgeForOfPicChain() { + if (GlobalObject* global = global_.unbarrieredGet()) { + if (NativeObject* object = global->getForOfPICObject()) { + ForOfPIC::Chain* chain = ForOfPIC::fromJSObject(object); + chain->freeAllStubs(runtime_->gcContext()); + } + } +} + +// Check to see if this individual realm is recording allocations. Debuggers or +// runtimes can try and record allocations, so this method can check to see if +// any initialization is needed. +bool Realm::isRecordingAllocations() { return !!allocationMetadataBuilder_; } + +void Realm::setAllocationMetadataBuilder( + const js::AllocationMetadataBuilder* builder) { + // Clear any jitcode in the runtime, which behaves differently depending on + // whether there is a creation callback. + ReleaseAllJITCode(runtime_->gcContext()); + + allocationMetadataBuilder_ = builder; +} + +void Realm::forgetAllocationMetadataBuilder() { + // Unlike setAllocationMetadataBuilder, we don't have to discard all JIT + // code here (code is still valid, just a bit slower because it doesn't do + // inline GC allocations when a metadata builder is present), but we do want + // to cancel off-thread Ion compilations to avoid races when Ion calls + // hasAllocationMetadataBuilder off-thread. + CancelOffThreadIonCompile(this); + + allocationMetadataBuilder_ = nullptr; +} + +void Realm::setNewObjectMetadata(JSContext* cx, HandleObject obj) { + MOZ_ASSERT(obj->maybeCCWRealm() == this); + cx->check(compartment(), obj); + + AutoEnterOOMUnsafeRegion oomUnsafe; + if (JSObject* metadata = + allocationMetadataBuilder_->build(cx, obj, oomUnsafe)) { + MOZ_ASSERT(metadata->maybeCCWRealm() == obj->maybeCCWRealm()); + cx->check(metadata); + + if (!objects_.objectMetadataTable) { + auto table = cx->make_unique<ObjectWeakMap>(cx); + if (!table) { + oomUnsafe.crash("setNewObjectMetadata"); + } + + objects_.objectMetadataTable = std::move(table); + } + + if (!objects_.objectMetadataTable->add(cx, obj, metadata)) { + oomUnsafe.crash("setNewObjectMetadata"); + } + } +} + +void Realm::updateDebuggerObservesFlag(unsigned flag) { + MOZ_ASSERT(isDebuggee()); + MOZ_ASSERT(flag == DebuggerObservesAllExecution || + flag == DebuggerObservesCoverage || + flag == DebuggerObservesAsmJS || flag == DebuggerObservesWasm); + + GlobalObject* global = + zone()->runtimeFromMainThread()->gc.isForegroundSweeping() + ? unsafeUnbarrieredMaybeGlobal() + : maybeGlobal(); + bool observes = false; + if (flag == DebuggerObservesAllExecution) { + observes = DebugAPI::debuggerObservesAllExecution(global); + } else if (flag == DebuggerObservesCoverage) { + observes = DebugAPI::debuggerObservesCoverage(global); + } else if (flag == DebuggerObservesAsmJS) { + observes = DebugAPI::debuggerObservesAsmJS(global); + } else if (flag == DebuggerObservesWasm) { + observes = DebugAPI::debuggerObservesWasm(global); + } + + if (observes) { + debugModeBits_ |= flag; + } else { + debugModeBits_ &= ~flag; + } +} + +void Realm::setIsDebuggee() { + if (!isDebuggee()) { + debugModeBits_ |= IsDebuggee; + runtimeFromMainThread()->incrementNumDebuggeeRealms(); + } +} + +void Realm::unsetIsDebuggee() { + if (isDebuggee()) { + if (debuggerObservesCoverage()) { + runtime_->decrementNumDebuggeeRealmsObservingCoverage(); + } + debugModeBits_ = 0; + DebugEnvironments::onRealmUnsetIsDebuggee(this); + runtimeFromMainThread()->decrementNumDebuggeeRealms(); + } +} + +void Realm::updateDebuggerObservesCoverage() { + bool previousState = debuggerObservesCoverage(); + updateDebuggerObservesFlag(DebuggerObservesCoverage); + if (previousState == debuggerObservesCoverage()) { + return; + } + + if (debuggerObservesCoverage()) { + // Interrupt any running interpreter frame. The scriptCounts are + // allocated on demand when a script resumes its execution. + JSContext* cx = TlsContext.get(); + for (ActivationIterator iter(cx); !iter.done(); ++iter) { + if (iter->isInterpreter()) { + iter->asInterpreter()->enableInterruptsUnconditionally(); + } + } + runtime_->incrementNumDebuggeeRealmsObservingCoverage(); + return; + } + + runtime_->decrementNumDebuggeeRealmsObservingCoverage(); + + // If code coverage is enabled by any other means, keep it. + if (collectCoverageForDebug()) { + return; + } + + clearScriptCounts(); + clearScriptLCov(); +} + +coverage::LCovRealm* Realm::lcovRealm() { + if (!lcovRealm_) { + lcovRealm_ = js::MakeUnique<coverage::LCovRealm>(this); + } + return lcovRealm_.get(); +} + +bool Realm::collectCoverageForDebug() const { + return debuggerObservesCoverage() || coverage::IsLCovEnabled(); +} + +void Realm::clearScriptCounts() { zone()->clearScriptCounts(this); } + +void Realm::clearScriptLCov() { zone()->clearScriptLCov(this); } + +void ObjectRealm::addSizeOfExcludingThis( + mozilla::MallocSizeOf mallocSizeOf, size_t* innerViewsArg, + size_t* objectMetadataTablesArg, + size_t* nonSyntacticLexicalEnvironmentsArg) { + *innerViewsArg += innerViews.sizeOfExcludingThis(mallocSizeOf); + + if (objectMetadataTable) { + *objectMetadataTablesArg += + objectMetadataTable->sizeOfIncludingThis(mallocSizeOf); + } + + if (auto& map = nonSyntacticLexicalEnvironments_) { + *nonSyntacticLexicalEnvironmentsArg += + map->sizeOfIncludingThis(mallocSizeOf); + } +} + +void Realm::addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf, + size_t* realmObject, size_t* realmTables, + size_t* innerViewsArg, + size_t* objectMetadataTablesArg, + size_t* savedStacksSet, + size_t* nonSyntacticLexicalEnvironmentsArg, + size_t* jitRealm) { + *realmObject += mallocSizeOf(this); + wasm.addSizeOfExcludingThis(mallocSizeOf, realmTables); + + objects_.addSizeOfExcludingThis(mallocSizeOf, innerViewsArg, + objectMetadataTablesArg, + nonSyntacticLexicalEnvironmentsArg); + + *savedStacksSet += savedStacks_.sizeOfExcludingThis(mallocSizeOf); + + if (jitRealm_) { + *jitRealm += jitRealm_->sizeOfIncludingThis(mallocSizeOf); + } +} + +bool Realm::shouldCaptureStackForThrow() { + // Determine whether a stack trace should be captured for throw-statements (or + // similar) in JS code in this realm. We don't want to do this unconditionally + // because capturing stacks is slow and some scripts throw a lot of + // exceptions. + // + // Note: this is unrelated to Error.stack! That property is observable from + // JS code so we can't use these heuristics there. The code here is mostly + // relevant for uncaught exceptions that are not Error objects. + + // To match other browsers, we always capture a stack trace if the realm is a + // debuggee (this includes the devtools console being open). + if (isDebuggee()) { + return true; + } + + // Also always capture for chrome code. This is code we control and this helps + // debugging. + if (principals() && + principals() == runtimeFromMainThread()->trustedPrincipals()) { + return true; + } + + // Else, capture the stack only for the first N exceptions so that we can + // still show stack traces for scripts that don't throw a lot of exceptions + // (if the console is opened later). + static constexpr uint16_t MaxStacksCapturedForThrow = 50; + if (numStacksCapturedForThrow_ > MaxStacksCapturedForThrow) { + return false; + } + numStacksCapturedForThrow_++; + return true; +} + +mozilla::HashCodeScrambler Realm::randomHashCodeScrambler() { + return mozilla::HashCodeScrambler(randomKeyGenerator_.next(), + randomKeyGenerator_.next()); +} + +AutoSetNewObjectMetadata::AutoSetNewObjectMetadata(JSContext* cx) + : cx_(cx), prevState_(cx, cx->realm()->objectMetadataState_) { + MOZ_ASSERT(cx_->isMainThreadContext()); + cx_->realm()->objectMetadataState_ = NewObjectMetadataState(DelayMetadata()); +} + +AutoSetNewObjectMetadata::~AutoSetNewObjectMetadata() { + if (!cx_->isExceptionPending() && cx_->realm()->hasObjectPendingMetadata()) { + // This destructor often runs upon exit from a function that is + // returning an unrooted pointer to a Cell. The allocation metadata + // callback often allocates; if it causes a GC, then the Cell pointer + // being returned won't be traced or relocated. + // + // The only extant callbacks are those internal to SpiderMonkey that + // capture the JS stack. In fact, we're considering removing general + // callbacks altogther in bug 1236748. Since it's not running arbitrary + // code, it's adequate to simply suppress GC while we run the callback. + gc::AutoSuppressGC autoSuppressGC(cx_); + + JSObject* obj = cx_->realm()->objectMetadataState_.as<PendingMetadata>(); + + // Make sure to restore the previous state before setting the object's + // metadata. SetNewObjectMetadata asserts that the state is not + // PendingMetadata in order to ensure that metadata callbacks are called + // in order. + cx_->realm()->objectMetadataState_ = prevState_; + + obj = SetNewObjectMetadata(cx_, obj); + } else { + cx_->realm()->objectMetadataState_ = prevState_; + } +} + +JS_PUBLIC_API void gc::TraceRealm(JSTracer* trc, JS::Realm* realm, + const char* name) { + // The way GC works with compartments is basically incomprehensible. + // For Realms, what we want is very simple: each Realm has a strong + // reference to its GlobalObject, and vice versa. + // + // Here we simply trace our side of that edge. During GC, + // GCRuntime::traceRuntimeCommon() marks all other realm roots, for + // all realms. + realm->traceGlobalData(trc); +} + +JS_PUBLIC_API JS::Realm* JS::GetCurrentRealmOrNull(JSContext* cx) { + return cx->realm(); +} + +JS_PUBLIC_API JS::Realm* JS::GetObjectRealmOrNull(JSObject* obj) { + return IsCrossCompartmentWrapper(obj) ? nullptr : obj->nonCCWRealm(); +} + +JS_PUBLIC_API void* JS::GetRealmPrivate(JS::Realm* realm) { + return realm->realmPrivate(); +} + +JS_PUBLIC_API void JS::SetRealmPrivate(JS::Realm* realm, void* data) { + realm->setRealmPrivate(data); +} + +JS_PUBLIC_API void JS::SetDestroyRealmCallback( + JSContext* cx, JS::DestroyRealmCallback callback) { + cx->runtime()->destroyRealmCallback = callback; +} + +JS_PUBLIC_API void JS::SetRealmNameCallback(JSContext* cx, + JS::RealmNameCallback callback) { + cx->runtime()->realmNameCallback = callback; +} + +JS_PUBLIC_API JSObject* JS::GetRealmGlobalOrNull(JS::Realm* realm) { + return realm->maybeGlobal(); +} + +JS_PUBLIC_API bool JS::InitRealmStandardClasses(JSContext* cx) { + MOZ_ASSERT(!cx->zone()->isAtomsZone()); + AssertHeapIsIdle(); + CHECK_THREAD(cx); + return GlobalObject::initStandardClasses(cx, cx->global()); +} + +JS_PUBLIC_API bool JS::MaybeFreezeCtorAndPrototype(JSContext* cx, + HandleObject ctor, + HandleObject maybeProto) { + if (MOZ_LIKELY(!cx->realm()->creationOptions().freezeBuiltins())) { + return true; + } + if (!SetIntegrityLevel(cx, ctor, IntegrityLevel::Frozen)) { + return false; + } + if (maybeProto) { + if (!SetIntegrityLevel(cx, maybeProto, IntegrityLevel::Sealed)) { + return false; + } + } + return true; +} + +JS_PUBLIC_API JSObject* JS::GetRealmObjectPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return &cx->global()->getObjectPrototype(); +} + +JS_PUBLIC_API JS::Handle<JSObject*> JS::GetRealmObjectPrototypeHandle( + JSContext* cx) { + return cx->global()->getObjectPrototypeHandle(); +} + +JS_PUBLIC_API JSObject* JS::GetRealmFunctionPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return &cx->global()->getFunctionPrototype(); +} + +JS_PUBLIC_API JSObject* JS::GetRealmArrayPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return GlobalObject::getOrCreateArrayPrototype(cx, cx->global()); +} + +JS_PUBLIC_API JSObject* JS::GetRealmErrorPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return GlobalObject::getOrCreateCustomErrorPrototype(cx, cx->global(), + JSEXN_ERR); +} + +JS_PUBLIC_API JSObject* JS::GetRealmIteratorPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return GlobalObject::getOrCreateIteratorPrototype(cx, cx->global()); +} + +JS_PUBLIC_API JSObject* JS::GetRealmAsyncIteratorPrototype(JSContext* cx) { + CHECK_THREAD(cx); + return GlobalObject::getOrCreateAsyncIteratorPrototype(cx, cx->global()); +} + +JS_PUBLIC_API JSObject* JS::GetRealmKeyObject(JSContext* cx) { + return GlobalObject::getOrCreateRealmKeyObject(cx, cx->global()); +} + +JS_PUBLIC_API Realm* JS::GetFunctionRealm(JSContext* cx, HandleObject objArg) { + // https://tc39.github.io/ecma262/#sec-getfunctionrealm + // 7.3.22 GetFunctionRealm ( obj ) + + CHECK_THREAD(cx); + cx->check(objArg); + + RootedObject obj(cx, objArg); + while (true) { + obj = CheckedUnwrapStatic(obj); + if (!obj) { + ReportAccessDenied(cx); + return nullptr; + } + + // Step 1. + MOZ_ASSERT(IsCallable(obj)); + + // Steps 2 and 3. We use a loop instead of recursion to unwrap bound + // functions. + if (obj->is<JSFunction>()) { + JSFunction* fun = &obj->as<JSFunction>(); + if (!fun->isBoundFunction()) { + return fun->realm(); + } + + obj = fun->getBoundFunctionTarget(); + continue; + } + + // WrappedFunctionObjects also have a [[Realm]] internal slot, + // which is the nonCCWRealm by construction. + if (obj->is<WrappedFunctionObject>()) { + return obj->nonCCWRealm(); + } + + // Step 4. + if (IsScriptedProxy(obj)) { + // Steps 4.a-b. + JSObject* proxyTarget = GetProxyTargetObject(obj); + if (!proxyTarget) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_PROXY_REVOKED); + return nullptr; + } + + // Step 4.c. + obj = proxyTarget; + continue; + } + + // Step 5. + return cx->realm(); + } +} |