1 // Copyright 2013 the V8 project authors. All rights reserved. 2 // Redistribution and use in source and binary forms, with or without 3 // modification, are permitted provided that the following conditions are 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 11 // with the distribution. 12 // * Neither the name of Google Inc. nor the names of its 13 // contributors may be used to endorse or promote products derived 14 // from this software without specific prior written permission. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_V8_PLATFORM_H_ 29 #define V8_V8_PLATFORM_H_ 30 31 #include "v8.h" 32 33 namespace v8 { 34 35 /** 36 * A Task represents a unit of work. 37 */ 38 class Task { 39 public: ~Task()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 */ 51 class 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: ~Platform()81 virtual ~Platform() {} 82 }; 83 84 } // namespace v8 85 86 #endif // V8_V8_PLATFORM_H_ 87