1edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project/* 2edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Copyright (C) 2007 The Android Open Source Project 3edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 4edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Licensed under the Apache License, Version 2.0 (the "License"); 5edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * you may not use this file except in compliance with the License. 6edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * You may obtain a copy of the License at 7edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 8edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * http://www.apache.org/licenses/LICENSE-2.0 9edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * 10edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * Unless required by applicable law or agreed to in writing, software 11edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * distributed under the License is distributed on an "AS IS" BASIS, 12edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * See the License for the specific language governing permissions and 14edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project * limitations under the License. 15edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project */ 16edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 17edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#ifndef ANDROID_BARRIER_H 18edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#define ANDROID_BARRIER_H 19edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 20edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#include <stdint.h> 21edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#include <sys/types.h> 22edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#include <utils/threads.h> 23edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 24edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectnamespace android { 25edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 26edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectclass Barrier 27edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project{ 28edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectpublic: 29edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project inline Barrier() : state(CLOSED) { } 30edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project inline ~Barrier() { } 31c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall 32c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // Release any threads waiting at the Barrier. 33c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // Provides release semantics: preceding loads and stores will be visible 34c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // to other threads before they wake up. 35edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project void open() { 36edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project Mutex::Autolock _l(lock); 37edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project state = OPENED; 38edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project cv.broadcast(); 39edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project } 40c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall 41c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // Reset the Barrier, so wait() will block until open() has been called. 42edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project void close() { 43edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project Mutex::Autolock _l(lock); 44edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project state = CLOSED; 45edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project } 46c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall 47c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // Wait until the Barrier is OPEN. 48c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // Provides acquire semantics: no subsequent loads or stores will occur 49c61576794e75898a829eac52fc524c8e907b4b02Jesse Hall // until wait() returns. 50edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project void wait() const { 51edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project Mutex::Autolock _l(lock); 52edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project while (state == CLOSED) { 53edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project cv.wait(lock); 54edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project } 55edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project } 56edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Projectprivate: 57edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project enum { OPENED, CLOSED }; 58edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project mutable Mutex lock; 59edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project mutable Condition cv; 60edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project volatile int state; 61edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project}; 62edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 63edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project}; // namespace android 64edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project 65edbf3b6af777b721cd2a1ef461947e51e88241e1The Android Open Source Project#endif // ANDROID_BARRIER_H 66