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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_PUBLIC_THREAD_SCHEDULER_H_
#define THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_PUBLIC_THREAD_SCHEDULER_H_
#include "base/location.h"
#include "base/task/single_thread_task_runner.h"
#include "base/time/time.h"
#include "third_party/blink/renderer/platform/scheduler/public/thread.h"
namespace v8 {
class Isolate;
}
namespace base {
class TaskObserver;
}
namespace blink {
class CompositorThreadScheduler;
class MainThreadScheduler;
// This class is used to submit tasks and pass other information from Blink to
// the platform's scheduler.
class PLATFORM_EXPORT ThreadScheduler {
public:
// Return the current thread's ThreadScheduler.
static ThreadScheduler* Current();
// Returns compositor thread scheduler for the compositor thread
// of the current process.
static blink::CompositorThreadScheduler* CompositorThreadScheduler();
virtual ~ThreadScheduler() = default;
// Called to prevent any more pending tasks from running. Must be called on
// the associated WebThread.
virtual void Shutdown() = 0;
// Returns true if there is high priority work pending on the associated
// WebThread and the caller should yield to let the scheduler service that
// work. Must be called on the associated WebThread.
virtual bool ShouldYieldForHighPriorityWork() = 0;
// Schedule an idle task to run the associated WebThread. For non-critical
// tasks which may be reordered relative to other task types and may be
// starved for an arbitrarily long time if no idle time is available.
// Takes ownership of |IdleTask|. Can be called from any thread.
virtual void PostIdleTask(const base::Location&, Thread::IdleTask) = 0;
// As above, except that the task is guaranteed to not run before |delay|.
// Takes ownership of |IdleTask|. Can be called from any thread.
virtual void PostDelayedIdleTask(const base::Location&,
base::TimeDelta delay,
Thread::IdleTask) = 0;
// Releases memory associated with cancelled idle tasks (best effort).
virtual void RemoveCancelledIdleTasks() = 0;
// Returns a task runner for kV8 tasks. Can be called from any thread.
virtual scoped_refptr<base::SingleThreadTaskRunner> V8TaskRunner() = 0;
// Returns a task runner for V8 user visible tasks. Can be called from any
// thread.
virtual scoped_refptr<base::SingleThreadTaskRunner>
V8UserVisibleTaskRunner() {
return nullptr;
}
// Returns a task runner for V8 best effort tasks. Can be called from any
// thread.
virtual scoped_refptr<base::SingleThreadTaskRunner> V8BestEffortTaskRunner() {
return nullptr;
}
// Returns a task runner for tasks to deallocate objects on the appropriate
// thread. This runner should only be used for freeing of resources.
// Execution of javascript will be prevented in the future on this task
// runner.
virtual scoped_refptr<base::SingleThreadTaskRunner> CleanupTaskRunner() = 0;
// Returns the current time recognized by the scheduler, which may perhaps
// be based on a real or virtual time domain. Used by Timer.
virtual base::TimeTicks MonotonicallyIncreasingVirtualTime() = 0;
// Adds or removes a task observer from the scheduler. The observer will be
// notified before and after every executed task. These functions can only be
// called on the thread this scheduler was created on.
virtual void AddTaskObserver(base::TaskObserver* task_observer) = 0;
virtual void RemoveTaskObserver(base::TaskObserver* task_observer) = 0;
// Associates |isolate| to the scheduler.
virtual void SetV8Isolate(v8::Isolate* isolate) = 0;
// Convert this into a MainThreadScheduler if it is one.
virtual MainThreadScheduler* ToMainThreadScheduler() { return nullptr; }
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_PLATFORM_SCHEDULER_PUBLIC_THREAD_SCHEDULER_H_
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