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// Copyright 2010 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/extensions/gc-extension.h"
#include "include/v8-isolate.h"
#include "include/v8-object.h"
#include "include/v8-persistent-handle.h"
#include "include/v8-primitive.h"
#include "include/v8-template.h"
#include "src/base/platform/platform.h"
#include "src/execution/isolate.h"
#include "src/heap/heap.h"
#include "src/tasks/cancelable-task.h"
namespace v8 {
namespace internal {
namespace {
enum class ExecutionType { kAsync, kSync };
struct GCOptions {
v8::Isolate::GarbageCollectionType type;
ExecutionType execution;
};
Maybe<bool> IsProperty(v8::Isolate* isolate, v8::Local<v8::Context> ctx,
v8::Local<v8::Object> object, const char* key,
const char* value) {
auto k = v8::String::NewFromUtf8(isolate, key).ToLocalChecked();
// Get will return undefined for non-existing keys which will make
// StrictEquals fail.
auto maybe_property = object->Get(ctx, k);
if (maybe_property.IsEmpty()) return Nothing<bool>();
return Just<bool>(maybe_property.ToLocalChecked()->StrictEquals(
v8::String::NewFromUtf8(isolate, value).ToLocalChecked()));
}
Maybe<GCOptions> Parse(v8::Isolate* isolate,
const v8::FunctionCallbackInfo<v8::Value>& args) {
// Default values.
auto options =
GCOptions{v8::Isolate::GarbageCollectionType::kFullGarbageCollection,
ExecutionType::kSync};
bool found_options_object = false;
if (args.Length() > 0 && args[0]->IsObject()) {
v8::HandleScope scope(isolate);
auto ctx = isolate->GetCurrentContext();
auto param = v8::Local<v8::Object>::Cast(args[0]);
auto maybe_type = IsProperty(isolate, ctx, param, "type", "minor");
if (maybe_type.IsNothing()) return Nothing<GCOptions>();
if (maybe_type.ToChecked()) {
found_options_object = true;
options.type =
v8::Isolate::GarbageCollectionType::kMinorGarbageCollection;
}
auto maybe_execution =
IsProperty(isolate, ctx, param, "execution", "async");
if (maybe_execution.IsNothing()) return Nothing<GCOptions>();
if (maybe_execution.ToChecked()) {
found_options_object = true;
options.execution = ExecutionType::kAsync;
}
}
// If no options object is present default to legacy behavior.
if (!found_options_object) {
options.type =
args[0]->BooleanValue(isolate)
? v8::Isolate::GarbageCollectionType::kMinorGarbageCollection
: v8::Isolate::GarbageCollectionType::kFullGarbageCollection;
}
return Just<GCOptions>(options);
}
void InvokeGC(v8::Isolate* isolate, v8::Isolate::GarbageCollectionType type,
v8::EmbedderHeapTracer::EmbedderStackState embedder_stack_state) {
Heap* heap = reinterpret_cast<Isolate*>(isolate)->heap();
switch (type) {
case v8::Isolate::GarbageCollectionType::kMinorGarbageCollection:
heap->CollectGarbage(i::NEW_SPACE, i::GarbageCollectionReason::kTesting,
kGCCallbackFlagForced);
break;
case v8::Isolate::GarbageCollectionType::kFullGarbageCollection:
heap->SetEmbedderStackStateForNextFinalization(embedder_stack_state);
heap->PreciseCollectAllGarbage(i::Heap::kNoGCFlags,
i::GarbageCollectionReason::kTesting,
kGCCallbackFlagForced);
break;
}
}
class AsyncGC final : public CancelableTask {
public:
~AsyncGC() final = default;
AsyncGC(v8::Isolate* isolate, v8::Local<v8::Promise::Resolver> resolver,
v8::Isolate::GarbageCollectionType type)
: CancelableTask(reinterpret_cast<Isolate*>(isolate)),
isolate_(isolate),
ctx_(isolate, isolate->GetCurrentContext()),
resolver_(isolate, resolver),
type_(type) {}
AsyncGC(const AsyncGC&) = delete;
AsyncGC& operator=(const AsyncGC&) = delete;
void RunInternal() final {
v8::HandleScope scope(isolate_);
InvokeGC(isolate_, type_,
v8::EmbedderHeapTracer::EmbedderStackState::kNoHeapPointers);
auto resolver = v8::Local<v8::Promise::Resolver>::New(isolate_, resolver_);
auto ctx = Local<v8::Context>::New(isolate_, ctx_);
resolver->Resolve(ctx, v8::Undefined(isolate_)).ToChecked();
}
private:
v8::Isolate* isolate_;
v8::Persistent<v8::Context> ctx_;
v8::Persistent<v8::Promise::Resolver> resolver_;
v8::Isolate::GarbageCollectionType type_;
};
} // namespace
v8::Local<v8::FunctionTemplate> GCExtension::GetNativeFunctionTemplate(
v8::Isolate* isolate, v8::Local<v8::String> str) {
return v8::FunctionTemplate::New(isolate, GCExtension::GC);
}
void GCExtension::GC(const v8::FunctionCallbackInfo<v8::Value>& args) {
v8::Isolate* isolate = args.GetIsolate();
// Immediate bailout if no arguments are provided.
if (args.Length() == 0) {
InvokeGC(
isolate, v8::Isolate::GarbageCollectionType::kFullGarbageCollection,
v8::EmbedderHeapTracer::EmbedderStackState::kMayContainHeapPointers);
return;
}
auto maybe_options = Parse(isolate, args);
if (maybe_options.IsNothing()) return;
GCOptions options = maybe_options.ToChecked();
switch (options.execution) {
case ExecutionType::kSync:
InvokeGC(
isolate, options.type,
v8::EmbedderHeapTracer::EmbedderStackState::kMayContainHeapPointers);
break;
case ExecutionType::kAsync: {
v8::HandleScope scope(isolate);
auto resolver = v8::Promise::Resolver::New(isolate->GetCurrentContext())
.ToLocalChecked();
args.GetReturnValue().Set(resolver->GetPromise());
auto task_runner =
V8::GetCurrentPlatform()->GetForegroundTaskRunner(isolate);
CHECK(task_runner->NonNestableTasksEnabled());
task_runner->PostNonNestableTask(
std::make_unique<AsyncGC>(isolate, resolver, options.type));
} break;
}
}
} // namespace internal
} // namespace v8
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