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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// ThreadUnsafeSharedPtr<T> is the same as shared_ptr<T> without the locking
// overhread (and thread-safety).
#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_THREAD_UNSAFE_SHARED_PTR_H__
#define GOOGLE_PROTOBUF_PYTHON_CPP_THREAD_UNSAFE_SHARED_PTR_H__
#include <algorithm>
#include <utility>
#include <google/protobuf/stubs/logging.h>
#include <google/protobuf/stubs/common.h>
namespace google {
namespace protobuf {
namespace python {
template <typename T>
class ThreadUnsafeSharedPtr {
public:
// Takes ownership.
explicit ThreadUnsafeSharedPtr(T* ptr)
: ptr_(ptr), refcount_(ptr ? new RefcountT(1) : nullptr) {
}
ThreadUnsafeSharedPtr(const ThreadUnsafeSharedPtr& other)
: ThreadUnsafeSharedPtr(nullptr) {
*this = other;
}
ThreadUnsafeSharedPtr& operator=(const ThreadUnsafeSharedPtr& other) {
if (other.refcount_ == refcount_) {
return *this;
}
this->~ThreadUnsafeSharedPtr();
ptr_ = other.ptr_;
refcount_ = other.refcount_;
if (refcount_) {
++*refcount_;
}
return *this;
}
~ThreadUnsafeSharedPtr() {
if (refcount_ == nullptr) {
GOOGLE_DCHECK(ptr_ == nullptr);
return;
}
if (--*refcount_ == 0) {
delete refcount_;
delete ptr_;
}
}
void reset(T* ptr = nullptr) { *this = ThreadUnsafeSharedPtr(ptr); }
T* get() { return ptr_; }
const T* get() const { return ptr_; }
void swap(ThreadUnsafeSharedPtr& other) {
using std::swap;
swap(ptr_, other.ptr_);
swap(refcount_, other.refcount_);
}
private:
typedef int RefcountT;
T* ptr_;
RefcountT* refcount_;
};
} // namespace python
} // namespace protobuf
} // namespace google
#endif // GOOGLE_PROTOBUF_PYTHON_CPP_THREAD_UNSAFE_SHARED_PTR_H__
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