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/*
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "cobalt/script/mozjs/mozjs_engine.h"
#include <algorithm>
#include "base/logging.h"
#include "cobalt/base/c_val.h"
#include "cobalt/browser/web_module.h"
#include "cobalt/script/mozjs/mozjs_global_environment.h"
#include "third_party/mozjs/cobalt_config/include/jscustomallocator.h"
#include "third_party/mozjs/js/src/jsapi.h"
namespace cobalt {
namespace script {
namespace mozjs {
namespace {
// After this many bytes have been allocated, the garbage collector will run.
const uint32_t kGarbageCollectionThresholdBytes = 8 * 1024 * 1024;
JSBool CheckAccessStub(JSContext*, JS::Handle<JSObject*>, JS::Handle<jsid>,
JSAccessMode, JS::MutableHandle<JS::Value>) {
return true;
}
JSSecurityCallbacks security_callbacks = {
CheckAccessStub,
MozjsGlobalEnvironment::CheckEval
};
class EngineStats {
public:
EngineStats();
static EngineStats* GetInstance() {
return Singleton<EngineStats,
StaticMemorySingletonTraits<EngineStats> >::get();
}
void EngineCreated() {
base::AutoLock auto_lock(lock_);
++engine_count_;
}
void EngineDestroyed() {
base::AutoLock auto_lock(lock_);
--engine_count_;
}
size_t UpdateMemoryStatsAndReturnReserved() {
base::AutoLock auto_lock(lock_);
if (engine_count_.value() == 0) {
return 0;
}
allocated_memory_ =
MemoryAllocatorReporter::Get()->GetCurrentBytesAllocated();
mapped_memory_ = MemoryAllocatorReporter::Get()->GetCurrentBytesMapped();
return allocated_memory_ + mapped_memory_;
}
private:
base::Lock lock_;
base::CVal<size_t, base::CValPublic> allocated_memory_;
base::CVal<size_t, base::CValPublic> mapped_memory_;
base::CVal<size_t> engine_count_;
};
EngineStats::EngineStats()
: allocated_memory_("Memory.JS.AllocatedMemory", 0,
"JS memory occupied by the Mozjs allocator."),
mapped_memory_("Memory.JS.MappedMemory", 0, "JS mapped memory."),
engine_count_("Count.JS.Engine", 0,
"Total JavaScript engine registered.") {
}
// Pretend we always preserve wrappers since we never call
// SetPreserveWrapperCallback anywhere else. This is necessary for
// TryPreserveReflector called by WeakMap to not crash. Disabling
// bindings to WeakMap does not appear to be an easy option because
// of its use in selfhosted.js. See bugzilla discussion linked where
// they decided to include a similar dummy in the mozjs shell.
// https://bugzilla.mozilla.org/show_bug.cgi?id=829798
bool DummyPreserveWrapperCallback(JSContext *cx, JSObject *obj) {
return true;
}
} // namespace
MozjsEngine::MozjsEngine() {
// TODO: Investigate the benefit of helper threads and things like
// parallel compilation.
runtime_ =
JS_NewRuntime(kGarbageCollectionThresholdBytes, JS_NO_HELPER_THREADS);
CHECK(runtime_);
// Sets the size of the native stack that should not be exceeded.
// Setting three quarters of the web module stack size to ensure that native
// stack won't exceed the stack size.
JS_SetNativeStackQuota(runtime_,
browser::WebModule::kWebModuleStackSize / 4 * 3);
JS_SetRuntimePrivate(runtime_, this);
JS_SetSecurityCallbacks(runtime_, &security_callbacks);
// Use incremental garbage collection.
JS_SetGCParameter(runtime_, JSGC_MODE, JSGC_MODE_INCREMENTAL);
// Allow Spidermonkey to allocate as much memory as it needs. If this limit
// is set we could limit the memory used by JS and "gracefully" restart,
// for example.
JS_SetGCParameter(runtime_, JSGC_MAX_BYTES, 0xffffffff);
// Callback to be called whenever a JSContext is created or destroyed for this
// JSRuntime.
JS_SetContextCallback(runtime_, &MozjsEngine::ContextCallback);
// Callback to be called at different points during garbage collection.
JS_SetGCCallback(runtime_, &MozjsEngine::GCCallback);
// Callback to be called during garbage collection during the sweep phase.
JS_SetFinalizeCallback(runtime_, &MozjsEngine::FinalizeCallback);
js::SetPreserveWrapperCallback(runtime_, DummyPreserveWrapperCallback);
EngineStats::GetInstance()->EngineCreated();
}
MozjsEngine::~MozjsEngine() {
DCHECK(thread_checker_.CalledOnValidThread());
EngineStats::GetInstance()->EngineDestroyed();
JS_DestroyRuntime(runtime_);
}
scoped_refptr<GlobalEnvironment> MozjsEngine::CreateGlobalEnvironment() {
DCHECK(thread_checker_.CalledOnValidThread());
return new MozjsGlobalEnvironment(runtime_);
}
void MozjsEngine::CollectGarbage() {
DCHECK(thread_checker_.CalledOnValidThread());
JS_GC(runtime_);
}
void MozjsEngine::ReportExtraMemoryCost(size_t bytes) { NOTIMPLEMENTED(); }
size_t MozjsEngine::UpdateMemoryStatsAndReturnReserved() {
return EngineStats::GetInstance()->UpdateMemoryStatsAndReturnReserved();
}
JSBool MozjsEngine::ContextCallback(JSContext* context, unsigned context_op) {
JSRuntime* runtime = JS_GetRuntime(context);
MozjsEngine* engine =
static_cast<MozjsEngine*>(JS_GetRuntimePrivate(runtime));
DCHECK(engine->thread_checker_.CalledOnValidThread());
if (context_op == JSCONTEXT_NEW) {
engine->contexts_.push_back(context);
} else if (context_op == JSCONTEXT_DESTROY) {
ContextVector::iterator it =
std::find(engine->contexts_.begin(), engine->contexts_.end(), context);
if (it != engine->contexts_.end()) {
engine->contexts_.erase(it);
}
}
return true;
}
void MozjsEngine::GCCallback(JSRuntime* runtime, JSGCStatus status) {
MozjsEngine* engine =
static_cast<MozjsEngine*>(JS_GetRuntimePrivate(runtime));
for (int i = 0; i < engine->contexts_.size(); ++i) {
MozjsGlobalEnvironment* global_environment =
MozjsGlobalEnvironment::GetFromContext(engine->contexts_[i]);
if (status == JSGC_BEGIN) {
global_environment->BeginGarbageCollection();
} else if (status == JSGC_END) {
global_environment->EndGarbageCollection();
}
}
}
void MozjsEngine::FinalizeCallback(JSFreeOp* free_op, JSFinalizeStatus status,
JSBool is_compartment) {
MozjsEngine* engine =
static_cast<MozjsEngine*>(JS_GetRuntimePrivate(free_op->runtime()));
DCHECK(engine->thread_checker_.CalledOnValidThread());
if (status == JSFINALIZE_GROUP_START) {
for (int i = 0; i < engine->contexts_.size(); ++i) {
MozjsGlobalEnvironment* global_environment =
MozjsGlobalEnvironment::GetFromContext(engine->contexts_[i]);
global_environment->DoSweep();
}
}
}
} // namespace mozjs
scoped_ptr<JavaScriptEngine> JavaScriptEngine::CreateEngine() {
return make_scoped_ptr<JavaScriptEngine>(new mozjs::MozjsEngine());
}
} // namespace script
} // namespace cobalt