113 lines
2.3 KiB
C++
113 lines
2.3 KiB
C++
// Copyright (C) 2014 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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#include "emugl/common/smart_ptr.h"
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#ifdef _WIN32
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#define WIN32_LEAN_AND_MEAN
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#include <windows.h>
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#endif
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namespace emugl {
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// Thread-safe atomic reference-counting type.
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class RefCount {
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public:
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RefCount() : mCount(1) {}
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~RefCount() {}
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// Technically not thread-safe, use only for testing.
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int count() const { return (int)mCount; }
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void increment() {
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#ifdef _WIN32
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InterlockedIncrement(&mCount);
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#else
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__sync_fetch_and_add(&mCount, 1);
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#endif
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}
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bool decrement() {
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#ifdef _WIN32
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return InterlockedDecrement(&mCount) == 0;
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#else
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return __sync_add_and_fetch(&mCount, -1) == 0;
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#endif
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}
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private:
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#ifdef _WIN32
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LONG mCount;
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#else
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int mCount;
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#endif
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};
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// SmartPtrBase implementation.
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SmartPtrBase::SmartPtrBase(void* ptr) : mPtr(ptr), mRefCount(NULL) {
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if (mPtr)
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mRefCount = new RefCount();
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}
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SmartPtrBase::SmartPtrBase(const SmartPtrBase& other)
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: mPtr(other.mPtr), mRefCount(other.mRefCount) {
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if (mRefCount)
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mRefCount->increment();
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}
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int SmartPtrBase::getRefCount() const {
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return mRefCount ? mRefCount->count() : 0;
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}
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void SmartPtrBase::addRef() {
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if (mRefCount)
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mRefCount->increment();
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}
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void* SmartPtrBase::copyFrom(const SmartPtrBase& other) {
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void* old_ptr = release();
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mPtr = other.mPtr;
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mRefCount = other.mRefCount;
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if (mRefCount)
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mRefCount->increment();
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return old_ptr;
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}
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void* SmartPtrBase::release() {
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void* old_ptr = mPtr;
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RefCount* old_refcount = mRefCount;
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if (old_refcount) {
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mPtr = NULL;
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mRefCount = NULL;
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if (old_refcount->decrement()) {
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delete old_refcount;
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return old_ptr;
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}
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}
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return NULL;
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}
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} // namespace emugl
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