src/v8/src/d8/d8-platforms.cc - cobalt - Git at Google

 // Copyright 2018 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 <memory>
 #include <unordered_map>

 #include "include/v8-platform.h"
 #include "src/base/logging.h"
 #include "src/base/macros.h"
 #include "src/base/platform/mutex.h"
 #include "src/base/platform/platform.h"
 #include "src/base/platform/time.h"
 #include "src/base/template-utils.h"
 #include "src/base/utils/random-number-generator.h"
 #include "src/d8/d8-platforms.h"

 namespace v8 {

 class PredictablePlatform : public Platform {
  public:
   explicit PredictablePlatform(std::unique_ptr<Platform> platform)
       : platform_(std::move(platform)) {
     DCHECK_NOT_NULL(platform_);
   }

   PageAllocator* GetPageAllocator() override {
     return platform_->GetPageAllocator();
   }

   void OnCriticalMemoryPressure() override {
     platform_->OnCriticalMemoryPressure();
   }

   bool OnCriticalMemoryPressure(size_t length) override {
     return platform_->OnCriticalMemoryPressure(length);
   }

   std::shared_ptr<TaskRunner> GetForegroundTaskRunner(
       v8::Isolate* isolate) override {
     return platform_->GetForegroundTaskRunner(isolate);
   }

   int NumberOfWorkerThreads() override { return 0; }

   void CallOnWorkerThread(std::unique_ptr<Task> task) override {
     // It's not defined when background tasks are being executed, so we can just
     // execute them right away.
     task->Run();
   }

   void CallDelayedOnWorkerThread(std::unique_ptr<Task> task,
                                  double delay_in_seconds) override {
     // Never run delayed tasks.
   }

   void CallOnForegroundThread(v8::Isolate* isolate, Task* task) override {
     // This is a deprecated function and should not be called anymore.
     UNREACHABLE();
   }

   void CallDelayedOnForegroundThread(v8::Isolate* isolate, Task* task,
                                      double delay_in_seconds) override {
     // This is a deprecated function and should not be called anymore.
     UNREACHABLE();
   }

   void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) override {
     UNREACHABLE();
   }

   bool IdleTasksEnabled(Isolate* isolate) override { return false; }

   double MonotonicallyIncreasingTime() override {
     return synthetic_time_in_sec_ += 0.00001;
   }

   double CurrentClockTimeMillis() override {
     return MonotonicallyIncreasingTime() * base::Time::kMillisecondsPerSecond;
   }

   v8::TracingController* GetTracingController() override {
     return platform_->GetTracingController();
   }

   Platform* platform() const { return platform_.get(); }

  private:
   double synthetic_time_in_sec_ = 0.0;
   std::unique_ptr<Platform> platform_;

   DISALLOW_COPY_AND_ASSIGN(PredictablePlatform);
 };

 std::unique_ptr<Platform> MakePredictablePlatform(
     std::unique_ptr<Platform> platform) {
   return base::make_unique<PredictablePlatform>(std::move(platform));
 }

 class DelayedTasksPlatform : public Platform {
  public:
   explicit DelayedTasksPlatform(std::unique_ptr<Platform> platform)
       : platform_(std::move(platform)) {
     DCHECK_NOT_NULL(platform_);
   }

   explicit DelayedTasksPlatform(std::unique_ptr<Platform> platform,
                                 int64_t random_seed)
       : platform_(std::move(platform)), rng_(random_seed) {
     DCHECK_NOT_NULL(platform_);
   }

   ~DelayedTasksPlatform() {
     // When the platform shuts down, all task runners must be freed.
     DCHECK_EQ(0, delayed_task_runners_.size());
   }

   PageAllocator* GetPageAllocator() override {
     return platform_->GetPageAllocator();
   }

   void OnCriticalMemoryPressure() override {
     platform_->OnCriticalMemoryPressure();
   }

   bool OnCriticalMemoryPressure(size_t length) override {
     return platform_->OnCriticalMemoryPressure(length);
   }

   std::shared_ptr<TaskRunner> GetForegroundTaskRunner(
       v8::Isolate* isolate) override {
     std::shared_ptr<TaskRunner> runner =
         platform_->GetForegroundTaskRunner(isolate);

     base::MutexGuard lock_guard(&mutex_);
     // Check if we can re-materialize the weak ptr in our map.
     std::weak_ptr<DelayedTaskRunner>& weak_delayed_runner =
         delayed_task_runners_[runner.get()];
     std::shared_ptr<DelayedTaskRunner> delayed_runner =
         weak_delayed_runner.lock();

     if (!delayed_runner) {
       // Create a new {DelayedTaskRunner} and keep a weak reference in our map.
       delayed_runner.reset(new DelayedTaskRunner(runner, this),
                            DelayedTaskRunnerDeleter{});
       weak_delayed_runner = delayed_runner;
     }

     return std::move(delayed_runner);
   }

   int NumberOfWorkerThreads() override {
     return platform_->NumberOfWorkerThreads();
   }

   void CallOnWorkerThread(std::unique_ptr<Task> task) override {
     platform_->CallOnWorkerThread(MakeDelayedTask(std::move(task)));
   }

   void CallDelayedOnWorkerThread(std::unique_ptr<Task> task,
                                  double delay_in_seconds) override {
     platform_->CallDelayedOnWorkerThread(MakeDelayedTask(std::move(task)),
                                          delay_in_seconds);
   }

   void CallOnForegroundThread(v8::Isolate* isolate, Task* task) override {
     // This is a deprecated function and should not be called anymore.
     UNREACHABLE();
   }

   void CallDelayedOnForegroundThread(v8::Isolate* isolate, Task* task,
                                      double delay_in_seconds) override {
     // This is a deprecated function and should not be called anymore.
     UNREACHABLE();
   }

   void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) override {
     // This is a deprecated function and should not be called anymore.
     UNREACHABLE();
   }

   bool IdleTasksEnabled(Isolate* isolate) override {
     return platform_->IdleTasksEnabled(isolate);
   }

   double MonotonicallyIncreasingTime() override {
     return platform_->MonotonicallyIncreasingTime();
   }

   double CurrentClockTimeMillis() override {
     return platform_->CurrentClockTimeMillis();
   }

   v8::TracingController* GetTracingController() override {
     return platform_->GetTracingController();
   }

  private:
   class DelayedTaskRunnerDeleter;
   class DelayedTaskRunner final : public TaskRunner {
    public:
     DelayedTaskRunner(std::shared_ptr<TaskRunner> task_runner,
                       DelayedTasksPlatform* platform)
         : task_runner_(task_runner), platform_(platform) {}

     void PostTask(std::unique_ptr<Task> task) final {
       task_runner_->PostTask(platform_->MakeDelayedTask(std::move(task)));
     }

     void PostDelayedTask(std::unique_ptr<Task> task,
                          double delay_in_seconds) final {
       task_runner_->PostDelayedTask(platform_->MakeDelayedTask(std::move(task)),
                                     delay_in_seconds);
     }

     void PostIdleTask(std::unique_ptr<IdleTask> task) final {
       task_runner_->PostIdleTask(
           platform_->MakeDelayedIdleTask(std::move(task)));
     }

     bool IdleTasksEnabled() final { return task_runner_->IdleTasksEnabled(); }

    private:
     friend class DelayedTaskRunnerDeleter;
     std::shared_ptr<TaskRunner> task_runner_;
     DelayedTasksPlatform* platform_;
   };

   class DelayedTaskRunnerDeleter {
    public:
     void operator()(DelayedTaskRunner* runner) const {
       TaskRunner* original_runner = runner->task_runner_.get();
       base::MutexGuard lock_guard(&runner->platform_->mutex_);
       auto& delayed_task_runners = runner->platform_->delayed_task_runners_;
       DCHECK_EQ(1, delayed_task_runners.count(original_runner));
       delayed_task_runners.erase(original_runner);
     }
   };

   class DelayedTask : public Task {
    public:
     DelayedTask(std::unique_ptr<Task> task, int32_t delay_ms)
         : task_(std::move(task)), delay_ms_(delay_ms) {}
     void Run() final {
       base::OS::Sleep(base::TimeDelta::FromMicroseconds(delay_ms_));
       task_->Run();
     }

    private:
     std::unique_ptr<Task> task_;
     int32_t delay_ms_;
   };

   class DelayedIdleTask : public IdleTask {
    public:
     DelayedIdleTask(std::unique_ptr<IdleTask> task, int32_t delay_ms)
         : task_(std::move(task)), delay_ms_(delay_ms) {}
     void Run(double deadline_in_seconds) final {
       base::OS::Sleep(base::TimeDelta::FromMicroseconds(delay_ms_));
       task_->Run(deadline_in_seconds);
     }

    private:
     std::unique_ptr<IdleTask> task_;
     int32_t delay_ms_;
   };

   std::unique_ptr<Platform> platform_;

   // The Mutex protects the RNG, which is used by foreground and background
   // threads, and the {delayed_task_runners_} map might be accessed concurrently
   // by the shared_ptr destructor.
   base::Mutex mutex_;
   base::RandomNumberGenerator rng_;
   std::unordered_map<TaskRunner*, std::weak_ptr<DelayedTaskRunner>>
       delayed_task_runners_;

   int32_t GetRandomDelayInMilliseconds() {
     base::MutexGuard lock_guard(&mutex_);
     double delay_fraction = rng_.NextDouble();
     // Sleep up to 100ms (100000us). Square {delay_fraction} to shift
     // distribution towards shorter sleeps.
     return 1e5 * (delay_fraction * delay_fraction);
   }

   std::unique_ptr<Task> MakeDelayedTask(std::unique_ptr<Task> task) {
     return base::make_unique<DelayedTask>(std::move(task),
                                           GetRandomDelayInMilliseconds());
   }

   std::unique_ptr<IdleTask> MakeDelayedIdleTask(
       std::unique_ptr<IdleTask> task) {
     return base::make_unique<DelayedIdleTask>(std::move(task),
                                               GetRandomDelayInMilliseconds());
   }

   DISALLOW_COPY_AND_ASSIGN(DelayedTasksPlatform);
 };

 std::unique_ptr<Platform> MakeDelayedTasksPlatform(
     std::unique_ptr<Platform> platform, int64_t random_seed) {
   if (random_seed) {
     return base::make_unique<DelayedTasksPlatform>(std::move(platform),
                                                    random_seed);
   }
   return base::make_unique<DelayedTasksPlatform>(std::move(platform));
 }

 }  // namespace v8
	// Copyright 2018 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 <memory>
	#include <unordered_map>

	#include "include/v8-platform.h"
	#include "src/base/logging.h"
	#include "src/base/macros.h"
	#include "src/base/platform/mutex.h"
	#include "src/base/platform/platform.h"
	#include "src/base/platform/time.h"
	#include "src/base/template-utils.h"
	#include "src/base/utils/random-number-generator.h"
	#include "src/d8/d8-platforms.h"

	namespace v8 {

	class PredictablePlatform : public Platform {
	public:
	explicit PredictablePlatform(std::unique_ptr<Platform> platform)
	: platform_(std::move(platform)) {
	DCHECK_NOT_NULL(platform_);
	}

	PageAllocator* GetPageAllocator() override {
	return platform_->GetPageAllocator();
	}

	void OnCriticalMemoryPressure() override {
	platform_->OnCriticalMemoryPressure();
	}

	bool OnCriticalMemoryPressure(size_t length) override {
	return platform_->OnCriticalMemoryPressure(length);
	}

	std::shared_ptr<TaskRunner> GetForegroundTaskRunner(
	v8::Isolate* isolate) override {
	return platform_->GetForegroundTaskRunner(isolate);
	}

	int NumberOfWorkerThreads() override { return 0; }

	void CallOnWorkerThread(std::unique_ptr<Task> task) override {
	// It's not defined when background tasks are being executed, so we can just
	// execute them right away.
	task->Run();
	}

	void CallDelayedOnWorkerThread(std::unique_ptr<Task> task,
	double delay_in_seconds) override {
	// Never run delayed tasks.
	}

	void CallOnForegroundThread(v8::Isolate* isolate, Task* task) override {
	// This is a deprecated function and should not be called anymore.
	UNREACHABLE();
	}

	void CallDelayedOnForegroundThread(v8::Isolate* isolate, Task* task,
	double delay_in_seconds) override {
	// This is a deprecated function and should not be called anymore.
	UNREACHABLE();
	}

	void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) override {
	UNREACHABLE();
	}

	bool IdleTasksEnabled(Isolate* isolate) override { return false; }

	double MonotonicallyIncreasingTime() override {
	return synthetic_time_in_sec_ += 0.00001;
	}

	double CurrentClockTimeMillis() override {
	return MonotonicallyIncreasingTime() * base::Time::kMillisecondsPerSecond;
	}

	v8::TracingController* GetTracingController() override {
	return platform_->GetTracingController();
	}

	Platform* platform() const { return platform_.get(); }

	private:
	double synthetic_time_in_sec_ = 0.0;
	std::unique_ptr<Platform> platform_;

	DISALLOW_COPY_AND_ASSIGN(PredictablePlatform);
	};

	std::unique_ptr<Platform> MakePredictablePlatform(
	std::unique_ptr<Platform> platform) {
	return base::make_unique<PredictablePlatform>(std::move(platform));
	}

	class DelayedTasksPlatform : public Platform {
	public:
	explicit DelayedTasksPlatform(std::unique_ptr<Platform> platform)
	: platform_(std::move(platform)) {
	DCHECK_NOT_NULL(platform_);
	}

	explicit DelayedTasksPlatform(std::unique_ptr<Platform> platform,
	int64_t random_seed)
	: platform_(std::move(platform)), rng_(random_seed) {
	DCHECK_NOT_NULL(platform_);
	}

	~DelayedTasksPlatform() {
	// When the platform shuts down, all task runners must be freed.
	DCHECK_EQ(0, delayed_task_runners_.size());
	}

	PageAllocator* GetPageAllocator() override {
	return platform_->GetPageAllocator();
	}

	void OnCriticalMemoryPressure() override {
	platform_->OnCriticalMemoryPressure();
	}

	bool OnCriticalMemoryPressure(size_t length) override {
	return platform_->OnCriticalMemoryPressure(length);
	}

	std::shared_ptr<TaskRunner> GetForegroundTaskRunner(
	v8::Isolate* isolate) override {
	std::shared_ptr<TaskRunner> runner =
	platform_->GetForegroundTaskRunner(isolate);

	base::MutexGuard lock_guard(&mutex_);
	// Check if we can re-materialize the weak ptr in our map.
	std::weak_ptr<DelayedTaskRunner>& weak_delayed_runner =
	delayed_task_runners_[runner.get()];
	std::shared_ptr<DelayedTaskRunner> delayed_runner =
	weak_delayed_runner.lock();

	if (!delayed_runner) {
	// Create a new {DelayedTaskRunner} and keep a weak reference in our map.
	delayed_runner.reset(new DelayedTaskRunner(runner, this),
	DelayedTaskRunnerDeleter{});
	weak_delayed_runner = delayed_runner;
	}

	return std::move(delayed_runner);
	}

	int NumberOfWorkerThreads() override {
	return platform_->NumberOfWorkerThreads();
	}

	void CallOnWorkerThread(std::unique_ptr<Task> task) override {
	platform_->CallOnWorkerThread(MakeDelayedTask(std::move(task)));
	}

	void CallDelayedOnWorkerThread(std::unique_ptr<Task> task,
	double delay_in_seconds) override {
	platform_->CallDelayedOnWorkerThread(MakeDelayedTask(std::move(task)),
	delay_in_seconds);
	}

	void CallOnForegroundThread(v8::Isolate* isolate, Task* task) override {
	// This is a deprecated function and should not be called anymore.
	UNREACHABLE();
	}

	void CallDelayedOnForegroundThread(v8::Isolate* isolate, Task* task,
	double delay_in_seconds) override {
	// This is a deprecated function and should not be called anymore.
	UNREACHABLE();
	}

	void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) override {
	// This is a deprecated function and should not be called anymore.
	UNREACHABLE();
	}

	bool IdleTasksEnabled(Isolate* isolate) override {
	return platform_->IdleTasksEnabled(isolate);
	}

	double MonotonicallyIncreasingTime() override {
	return platform_->MonotonicallyIncreasingTime();
	}

	double CurrentClockTimeMillis() override {
	return platform_->CurrentClockTimeMillis();
	}

	v8::TracingController* GetTracingController() override {
	return platform_->GetTracingController();
	}

	private:
	class DelayedTaskRunnerDeleter;
	class DelayedTaskRunner final : public TaskRunner {
	public:
	DelayedTaskRunner(std::shared_ptr<TaskRunner> task_runner,
	DelayedTasksPlatform* platform)
	: task_runner_(task_runner), platform_(platform) {}

	void PostTask(std::unique_ptr<Task> task) final {
	task_runner_->PostTask(platform_->MakeDelayedTask(std::move(task)));
	}

	void PostDelayedTask(std::unique_ptr<Task> task,
	double delay_in_seconds) final {
	task_runner_->PostDelayedTask(platform_->MakeDelayedTask(std::move(task)),
	delay_in_seconds);
	}

	void PostIdleTask(std::unique_ptr<IdleTask> task) final {
	task_runner_->PostIdleTask(
	platform_->MakeDelayedIdleTask(std::move(task)));
	}

	bool IdleTasksEnabled() final { return task_runner_->IdleTasksEnabled(); }

	private:
	friend class DelayedTaskRunnerDeleter;
	std::shared_ptr<TaskRunner> task_runner_;
	DelayedTasksPlatform* platform_;
	};

	class DelayedTaskRunnerDeleter {
	public:
	void operator()(DelayedTaskRunner* runner) const {
	TaskRunner* original_runner = runner->task_runner_.get();
	base::MutexGuard lock_guard(&runner->platform_->mutex_);
	auto& delayed_task_runners = runner->platform_->delayed_task_runners_;
	DCHECK_EQ(1, delayed_task_runners.count(original_runner));
	delayed_task_runners.erase(original_runner);
	}
	};

	class DelayedTask : public Task {
	public:
	DelayedTask(std::unique_ptr<Task> task, int32_t delay_ms)
	: task_(std::move(task)), delay_ms_(delay_ms) {}
	void Run() final {
	base::OS::Sleep(base::TimeDelta::FromMicroseconds(delay_ms_));
	task_->Run();
	}

	private:
	std::unique_ptr<Task> task_;
	int32_t delay_ms_;
	};

	class DelayedIdleTask : public IdleTask {
	public:
	DelayedIdleTask(std::unique_ptr<IdleTask> task, int32_t delay_ms)
	: task_(std::move(task)), delay_ms_(delay_ms) {}
	void Run(double deadline_in_seconds) final {
	base::OS::Sleep(base::TimeDelta::FromMicroseconds(delay_ms_));
	task_->Run(deadline_in_seconds);
	}

	private:
	std::unique_ptr<IdleTask> task_;
	int32_t delay_ms_;
	};

	std::unique_ptr<Platform> platform_;

	// The Mutex protects the RNG, which is used by foreground and background
	// threads, and the {delayed_task_runners_} map might be accessed concurrently
	// by the shared_ptr destructor.
	base::Mutex mutex_;
	base::RandomNumberGenerator rng_;
	std::unordered_map<TaskRunner*, std::weak_ptr<DelayedTaskRunner>>
	delayed_task_runners_;

	int32_t GetRandomDelayInMilliseconds() {
	base::MutexGuard lock_guard(&mutex_);
	double delay_fraction = rng_.NextDouble();
	// Sleep up to 100ms (100000us). Square {delay_fraction} to shift
	// distribution towards shorter sleeps.
	return 1e5 * (delay_fraction * delay_fraction);
	}

	std::unique_ptr<Task> MakeDelayedTask(std::unique_ptr<Task> task) {
	return base::make_unique<DelayedTask>(std::move(task),
	GetRandomDelayInMilliseconds());
	}

	std::unique_ptr<IdleTask> MakeDelayedIdleTask(
	std::unique_ptr<IdleTask> task) {
	return base::make_unique<DelayedIdleTask>(std::move(task),
	GetRandomDelayInMilliseconds());
	}

	DISALLOW_COPY_AND_ASSIGN(DelayedTasksPlatform);
	};

	std::unique_ptr<Platform> MakeDelayedTasksPlatform(
	std::unique_ptr<Platform> platform, int64_t random_seed) {
	if (random_seed) {
	return base::make_unique<DelayedTasksPlatform>(std::move(platform),
	random_seed);
	}
	return base::make_unique<DelayedTasksPlatform>(std::move(platform));
	}

	} // namespace v8