| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include "Semaphore.h" |
| |
| #include <decaf/lang/Integer.h> |
| |
| #include <decaf/util/concurrent/locks/AbstractQueuedSynchronizer.h> |
| |
| using namespace decaf; |
| using namespace decaf::lang; |
| using namespace decaf::lang::exceptions; |
| using namespace decaf::util; |
| using namespace decaf::util::concurrent; |
| using namespace decaf::util::concurrent::locks; |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| namespace decaf { |
| namespace util { |
| namespace concurrent { |
| |
| class SemSync : public AbstractQueuedSynchronizer{ |
| public: |
| |
| SemSync(int permits) : AbstractQueuedSynchronizer() { |
| this->setState(permits); |
| } |
| virtual ~SemSync() {} |
| |
| virtual bool isFair() const = 0; |
| |
| int getPermits() { |
| return getState(); |
| } |
| |
| int nonfairTryAcquireShared(int acquires) { |
| for (;;) { |
| int available = getState(); |
| int remaining = available - acquires; |
| if (remaining < 0 || compareAndSetState(available, remaining)) { |
| return remaining; |
| } |
| } |
| } |
| |
| void reducePermits(int reductions) { |
| for (;;) { |
| int current = getState(); |
| int next = current - reductions; |
| if (compareAndSetState(current, next)) { |
| return; |
| } |
| } |
| } |
| |
| int drainPermits() { |
| for (;;) { |
| int current = getState(); |
| if (current == 0 || compareAndSetState(current, 0)) { |
| return current; |
| } |
| } |
| } |
| |
| protected: |
| |
| virtual bool tryReleaseShared(int releases) { |
| for (;;) { |
| int p = getState(); |
| if (compareAndSetState(p, p + releases)) { |
| return true; |
| } |
| } |
| } |
| |
| }; |
| |
| class NonFairSemSync : public SemSync { |
| public: |
| |
| NonFairSemSync(int permits) : SemSync(permits) {} |
| virtual ~NonFairSemSync() {} |
| |
| virtual bool isFair() const { |
| return false; |
| } |
| |
| protected: |
| |
| virtual int tryAcquireShared(int acquires) { |
| return nonfairTryAcquireShared(acquires); |
| } |
| }; |
| |
| class FairSemSync : public SemSync { |
| public: |
| |
| FairSemSync(int permits) : SemSync(permits) {} |
| virtual ~FairSemSync() {} |
| |
| virtual bool isFair() const { |
| return true; |
| } |
| |
| protected: |
| |
| virtual int tryAcquireShared(int acquires) { |
| Thread* current = Thread::currentThread(); |
| for(;;) { |
| Thread* first = this->getFirstQueuedThread(); |
| |
| if (first != NULL && first != current) { |
| return -1; |
| } |
| |
| int available = getState(); |
| int remaining = available - acquires; |
| if (remaining < 0 || compareAndSetState(available, remaining)) { |
| return remaining; |
| } |
| } |
| } |
| }; |
| |
| }}} |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| Semaphore::Semaphore(int permits) : sync(new NonFairSemSync(permits)) { |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| Semaphore::Semaphore(int permits, bool fair) : sync(NULL) { |
| fair == true ? sync = new FairSemSync(permits) : sync = new NonFairSemSync(permits); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| Semaphore::~Semaphore() { |
| try{ |
| delete sync; |
| } |
| DECAF_CATCHALL_NOTHROW() |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::acquire() { |
| this->sync->acquireSharedInterruptibly(1); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::acquireUninterruptibly() { |
| this->sync->acquireShared(1); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::tryAcquire() { |
| return this->sync->nonfairTryAcquireShared(1) >= 0; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::tryAcquire(long long timeout, const TimeUnit& unit) { |
| return this->sync->tryAcquireSharedNanos(1, unit.toNanos(timeout)); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::release() { |
| this->sync->releaseShared(1); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::acquire(int permits) { |
| |
| if (permits < 0) { |
| throw new IllegalArgumentException(__FILE__, __LINE__, |
| "Value of acquired permits must be greater than zero."); |
| } |
| |
| this->sync->acquireSharedInterruptibly(permits); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::acquireUninterruptibly( int permits DECAF_UNUSED ) { |
| |
| if (permits < 0) { |
| throw new IllegalArgumentException(__FILE__, __LINE__, |
| "Value of acquired permits must be greater than zero."); |
| } |
| |
| this->sync->acquireShared(permits); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::tryAcquire(int permits) { |
| |
| if (permits < 0) { |
| throw new IllegalArgumentException(__FILE__, __LINE__, |
| "Value of acquired permits must be greater than zero."); |
| } |
| |
| return this->sync->nonfairTryAcquireShared(permits) >= 0; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::tryAcquire(int permits, long long timeout, const TimeUnit& unit) { |
| |
| if (permits < 0) { |
| throw new IllegalArgumentException(__FILE__, __LINE__, |
| "Value of acquired permits must be greater than zero."); |
| } |
| |
| return this->sync->tryAcquireSharedNanos(permits, unit.toNanos(timeout)); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::release(int permits) { |
| |
| if (permits < 0) { |
| throw new IllegalArgumentException(__FILE__, __LINE__, |
| "Value of acquired permits must be greater than zero."); |
| } |
| |
| this->sync->releaseShared(permits); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| int Semaphore::availablePermits() const { |
| return this->sync->getPermits(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| int Semaphore::drainPermits() { |
| return this->sync->drainPermits(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| void Semaphore::reducePermits(int reduceBy) { |
| return this->sync->reducePermits(reduceBy); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::isFair() const { |
| return this->sync->isFair(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| std::string Semaphore::toString() const { |
| return std::string("Semaphore[Permits = ") + Integer::toString(this->sync->getPermits()) + "]"; |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| int Semaphore::getQueueLength() const { |
| return this->sync->getQueueLength(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| bool Semaphore::hasQueuedThreads() const { |
| return this->sync->hasQueuedThreads(); |
| } |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| Collection<decaf::lang::Thread*>* Semaphore::getQueuedThreads() const { |
| return this->sync->getQueuedThreads(); |
| } |