84 lines
2.6 KiB
C
84 lines
2.6 KiB
C
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/*
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* Copyright (C) 2011 Google Inc.
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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 SkTScopedPtr_DEFINED
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#define SkTScopedPtr_DEFINED
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#include "SkTypes.h"
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/** \class SkTScopedPtr
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A SkTScopedPtr<T> is like a T*, except that the destructor of SkTScopedPtr<T>
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automatically deletes the pointer it holds (if any). That is, SkTScopedPtr<T>
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owns the T object that it points to. Like a T*, a SkTScopedPtr<T> may hold
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either NULL or a pointer to a T object. Also like T*, SkTScopedPtr<T> is
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thread-compatible, and once you dereference it, you get the threadsafety
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guarantees of T.
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The size of a SkTScopedPtr is small: sizeof(SkTScopedPtr<T>) == sizeof(T*)
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*/
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template <typename T> class SkTScopedPtr : SkNoncopyable {
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public:
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explicit SkTScopedPtr(T* o = NULL) : fObj(o) {}
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~SkTScopedPtr() {
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enum { kTypeMustBeComplete = sizeof(T) };
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delete fObj;
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}
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/** Delete the current object, if any. Then take ownership of the
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passed object.
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*/
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void reset(T* o = NULL) {
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if (o != fObj) {
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enum { kTypeMustBeComplete = sizeof(T) };
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delete fObj;
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fObj = o;
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}
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}
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/** Without deleting the current object, return it and forget about it.
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Similar to calling get() and reset(), but the object is not deleted.
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*/
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T* release() {
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T* retVal = fObj;
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fObj = NULL;
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return retVal;
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}
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T& operator*() const {
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SkASSERT(fObj != NULL);
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return *fObj;
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}
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T* operator->() const {
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SkASSERT(fObj != NULL);
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return fObj;
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}
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T* get() const { return fObj; }
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bool operator==(T* o) const { return fObj == o; }
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bool operator!=(T* o) const { return fObj != o; }
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private:
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T* fObj;
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// Forbid comparison of SkTScopedPtr types. If T2 != T, it doesn't make
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// sense, and if T2 == T, it still doesn't make sense because the same
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// object can't be owned by two different scoped_ptrs.
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template <class T2> bool operator==(SkTScopedPtr<T2> const& o2) const;
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template <class T2> bool operator!=(SkTScopedPtr<T2> const& o2) const;
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};
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#endif
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