| // Copyright 2013 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. |
| |
| #ifndef V8_V8_PLATFORM_H_ |
| #define V8_V8_PLATFORM_H_ |
| |
| namespace v8 { |
| |
| class Isolate; |
| |
| /** |
| * A Task represents a unit of work. |
| */ |
| class Task { |
| public: |
| virtual ~Task() {} |
| |
| virtual void Run() = 0; |
| }; |
| |
| /** |
| * V8 Platform abstraction layer. |
| * |
| * The embedder has to provide an implementation of this interface before |
| * initializing the rest of V8. |
| */ |
| class Platform { |
| public: |
| /** |
| * This enum is used to indicate whether a task is potentially long running, |
| * or causes a long wait. The embedder might want to use this hint to decide |
| * whether to execute the task on a dedicated thread. |
| */ |
| enum ExpectedRuntime { |
| kShortRunningTask, |
| kLongRunningTask |
| }; |
| |
| virtual ~Platform() {} |
| |
| /** |
| * Schedules a task to be invoked on a background thread. |expected_runtime| |
| * indicates that the task will run a long time. The Platform implementation |
| * takes ownership of |task|. There is no guarantee about order of execution |
| * of tasks wrt order of scheduling, nor is there a guarantee about the |
| * thread the task will be run on. |
| */ |
| virtual void CallOnBackgroundThread(Task* task, |
| ExpectedRuntime expected_runtime) = 0; |
| |
| /** |
| * Schedules a task to be invoked on a foreground thread wrt a specific |
| * |isolate|. Tasks posted for the same isolate should be execute in order of |
| * scheduling. The definition of "foreground" is opaque to V8. |
| */ |
| virtual void CallOnForegroundThread(Isolate* isolate, Task* task) = 0; |
| |
| /** |
| * Monotonically increasing time in seconds from an arbitrary fixed point in |
| * the past. This function is expected to return at least |
| * millisecond-precision values. For this reason, |
| * it is recommended that the fixed point be no further in the past than |
| * the epoch. |
| **/ |
| virtual double MonotonicallyIncreasingTime() = 0; |
| }; |
| |
| } // namespace v8 |
| |
| #endif // V8_V8_PLATFORM_H_ |