/*
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* Copyright 2013 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkDiscardableMemory_DEFINED
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#define SkDiscardableMemory_DEFINED
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#include "SkRefCnt.h"
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#include "SkTypes.h"
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/**
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* Interface for discardable memory. Implementation is provided by the
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* embedder.
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*/
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class SK_API SkDiscardableMemory {
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public:
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/**
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* Factory method that creates, initializes and locks an SkDiscardableMemory
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* object. If either of these steps fails, a nullptr pointer will be returned.
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*/
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static SkDiscardableMemory* Create(size_t bytes);
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/**
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* Factory class that creates, initializes and locks an SkDiscardableMemory
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* object. If either of these steps fails, a nullptr pointer will be returned.
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*/
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class Factory : public SkRefCnt {
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public:
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virtual SkDiscardableMemory* create(size_t bytes) = 0;
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private:
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typedef SkRefCnt INHERITED;
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};
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/** Must not be called while locked.
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*/
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virtual ~SkDiscardableMemory() {}
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/**
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* Locks the memory, prevent it from being discarded. Once locked. you may
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* obtain a pointer to that memory using the data() method.
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*
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* lock() may return false, indicating that the underlying memory was
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* discarded and that the lock failed.
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*
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* Nested calls to lock are not allowed.
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*/
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virtual bool SK_WARN_UNUSED_RESULT lock() = 0;
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/**
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* Returns the current pointer for the discardable memory. This call is ONLY
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* valid when the discardable memory object is locked.
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*/
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virtual void* data() = 0;
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/**
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* Unlock the memory so that it can be purged by the system. Must be called
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* after every successful lock call.
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*/
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virtual void unlock() = 0;
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};
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#endif
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