// Copyright (c) 2006, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#ifndef GOOGLE_PROTOBUF_STUBS_MUTEX_H_
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#define GOOGLE_PROTOBUF_STUBS_MUTEX_H_
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#ifdef GOOGLE_PROTOBUF_NO_THREADLOCAL
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#include <pthread.h>
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#endif
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#include <google/protobuf/stubs/macros.h>
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// ===================================================================
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// emulates google3/base/mutex.h
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namespace google {
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namespace protobuf {
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namespace internal {
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// A Mutex is a non-reentrant (aka non-recursive) mutex. At most one thread T
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// may hold a mutex at a given time. If T attempts to Lock() the same Mutex
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// while holding it, T will deadlock.
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class LIBPROTOBUF_EXPORT Mutex {
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public:
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// Create a Mutex that is not held by anybody.
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Mutex();
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// Destructor
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~Mutex();
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// Block if necessary until this Mutex is free, then acquire it exclusively.
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void Lock();
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// Release this Mutex. Caller must hold it exclusively.
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void Unlock();
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// Crash if this Mutex is not held exclusively by this thread.
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// May fail to crash when it should; will never crash when it should not.
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void AssertHeld();
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private:
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struct Internal;
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Internal* mInternal;
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Mutex);
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};
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// Undefine the macros to workaround the conflicts with Google internal
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// MutexLock implementation.
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// TODO(liujisi): Remove the undef once internal macros are removed.
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#undef MutexLock
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#undef ReaderMutexLock
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#undef WriterMutexLock
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#undef MutexLockMaybe
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// MutexLock(mu) acquires mu when constructed and releases it when destroyed.
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class LIBPROTOBUF_EXPORT MutexLock {
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public:
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explicit MutexLock(Mutex *mu) : mu_(mu) { this->mu_->Lock(); }
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~MutexLock() { this->mu_->Unlock(); }
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private:
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Mutex *const mu_;
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MutexLock);
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};
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// TODO(kenton): Implement these? Hard to implement portably.
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typedef MutexLock ReaderMutexLock;
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typedef MutexLock WriterMutexLock;
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// MutexLockMaybe is like MutexLock, but is a no-op when mu is NULL.
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class LIBPROTOBUF_EXPORT MutexLockMaybe {
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public:
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explicit MutexLockMaybe(Mutex *mu) :
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mu_(mu) { if (this->mu_ != NULL) { this->mu_->Lock(); } }
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~MutexLockMaybe() { if (this->mu_ != NULL) { this->mu_->Unlock(); } }
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private:
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Mutex *const mu_;
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(MutexLockMaybe);
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};
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#if defined(GOOGLE_PROTOBUF_NO_THREADLOCAL)
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template<typename T>
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class ThreadLocalStorage {
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public:
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ThreadLocalStorage() {
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pthread_key_create(&key_, &ThreadLocalStorage::Delete);
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}
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~ThreadLocalStorage() {
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pthread_key_delete(key_);
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}
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T* Get() {
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T* result = static_cast<T*>(pthread_getspecific(key_));
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if (result == NULL) {
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result = new T();
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pthread_setspecific(key_, result);
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}
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return result;
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}
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private:
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static void Delete(void* value) {
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delete static_cast<T*>(value);
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}
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pthread_key_t key_;
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(ThreadLocalStorage);
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};
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#endif
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} // namespace internal
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// We made these internal so that they would show up as such in the docs,
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// but we don't want to stick "internal::" in front of them everywhere.
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using internal::Mutex;
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using internal::MutexLock;
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using internal::ReaderMutexLock;
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using internal::WriterMutexLock;
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using internal::MutexLockMaybe;
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} // namespace protobuf
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} // namespace google
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#endif // GOOGLE_PROTOBUF_STUBS_MUTEX_H_
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