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27
28#ifndef V8_V8_PLATFORM_H_
29#define V8_V8_PLATFORM_H_
30
31#include "v8.h"
32
33namespace v8 {
34
35/**
36 * A Task represents a unit of work.
37 */
38class Task {
39 public:
40  virtual ~Task() {}
41
42  virtual void Run() = 0;
43};
44
45/**
46 * V8 Platform abstraction layer.
47 *
48 * The embedder has to provide an implementation of this interface before
49 * initializing the rest of V8.
50 */
51class Platform {
52 public:
53  /**
54   * This enum is used to indicate whether a task is potentially long running,
55   * or causes a long wait. The embedder might want to use this hint to decide
56   * whether to execute the task on a dedicated thread.
57   */
58  enum ExpectedRuntime {
59    kShortRunningTask,
60    kLongRunningTask
61  };
62
63  /**
64   * Schedules a task to be invoked on a background thread. |expected_runtime|
65   * indicates that the task will run a long time. The Platform implementation
66   * takes ownership of |task|. There is no guarantee about order of execution
67   * of tasks wrt order of scheduling, nor is there a guarantee about the
68   * thread the task will be run on.
69   */
70  virtual void CallOnBackgroundThread(Task* task,
71                                      ExpectedRuntime expected_runtime) = 0;
72
73  /**
74   * Schedules a task to be invoked on a foreground thread wrt a specific
75   * |isolate|. Tasks posted for the same isolate should be execute in order of
76   * scheduling. The definition of "foreground" is opaque to V8.
77   */
78  virtual void CallOnForegroundThread(Isolate* isolate, Task* task) = 0;
79
80 protected:
81  virtual ~Platform() {}
82};
83
84}  // namespace v8
85
86#endif  // V8_V8_PLATFORM_H_
87