60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
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/*
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* Copyright (C) 2007 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef ANDROID_BARRIER_H
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#define ANDROID_BARRIER_H
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#include <stdint.h>
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#include <sys/types.h>
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#include <utils/threads.h>
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namespace android {
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class Barrier
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{
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public:
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inline Barrier() : state(CLOSED) { }
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inline ~Barrier() { }
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void open() {
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// gcc memory barrier, this makes sure all memory writes
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// have been issued by gcc. On an SMP system we'd need a real
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// h/w barrier.
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asm volatile ("":::"memory");
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Mutex::Autolock _l(lock);
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state = OPENED;
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cv.broadcast();
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}
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void close() {
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Mutex::Autolock _l(lock);
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state = CLOSED;
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}
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void wait() const {
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Mutex::Autolock _l(lock);
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while (state == CLOSED) {
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cv.wait(lock);
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}
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}
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private:
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enum { OPENED, CLOSED };
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mutable Mutex lock;
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mutable Condition cv;
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volatile int state;
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};
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}; // namespace android
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#endif // ANDROID_BARRIER_H
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