ac10a2d039
git-svn-id: http://skia.googlecode.com/svn/trunk@649 2bbb7eff-a529-9590-31e7-b0007b416f81
126 lines
2.9 KiB
C++
126 lines
2.9 KiB
C++
/*
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Copyright 2010 Google Inc.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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 GrRefCnt_DEFINED
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#define GrRefCnt_DEFINED
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#include "GrTypes.h"
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#include "GrNoncopyable.h"
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/**
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* Base class for reference counting. When an object is first instantiated,
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* its reference count is 1. If the object may be null, use GrSafeRef() and
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* GrSafeUnref().
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*
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* It is an error (though only checked for in the debug build) to call unref()
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* such that the reference count becomes 0.
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*/
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class GrRefCnt : GrNoncopyable {
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public:
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GrRefCnt() : fRefCnt(1) {}
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virtual ~GrRefCnt() {
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GrAssert(1 == fRefCnt);
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#if GR_DEBUG
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fRefCnt = 0; // force validate() to trigger if called afterwards
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#endif
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}
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int32_t refcnt() const { return fRefCnt; }
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void ref() const {
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GrAssert(fRefCnt > 0);
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++fRefCnt;
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}
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void unref() const {
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GrAssert(fRefCnt > 0);
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if (1 == fRefCnt) {
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delete this;
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} else {
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--fRefCnt;
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}
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}
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#if GR_DEBUG
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void validate() const {
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GrAssert(fRefCnt > 0);
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}
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#else
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void validate() const {}
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#endif
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private:
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mutable int32_t fRefCnt;
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};
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///////////////////////////////////////////////////////////////////////////////
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/**
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* Call with instance/subclass of GrRefCnt. This does nothing if obj is null,
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* but otherwise it calls ref().
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*/
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static inline void GrSafeRef(const GrRefCnt* obj) {
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if (obj) {
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obj->ref();
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}
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}
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/**
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* Call with instance/subclass of GrRefCnt. This does nothing if obj is null,
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* but otherwise it calls unref().
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*/
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static inline void GrSafeUnref(const GrRefCnt* obj) {
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if (obj) {
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obj->unref();
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}
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}
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/**
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* Assigns src to dst, checking for NULLs in each, and correctly incrementing
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* the reference count of src, and decrementing the reference count of dst
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*/
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static inline void GrSafeAssign(GrRefCnt*& dst, GrRefCnt* src) {
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if (src) {
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src->ref();
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}
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if (dst) {
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dst->unref();
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}
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dst = src;
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}
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///////////////////////////////////////////////////////////////////////////////
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class GrAutoRef : GrNoncopyable {
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public:
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GrAutoRef(GrRefCnt* obj) : fObj(obj) { GrSafeRef(obj); }
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~GrAutoRef() { GrSafeUnref(fObj); }
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private:
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GrRefCnt* fObj;
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};
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class GrAutoUnref : GrNoncopyable {
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public:
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GrAutoUnref(GrRefCnt* obj) : fObj(obj) {}
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~GrAutoUnref() { GrSafeUnref(fObj); }
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private:
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GrRefCnt* fObj;
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};
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#endif
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