1 /* 2 * Copyright 2013 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef SkDiscardableMemory_DEFINED 9 #define SkDiscardableMemory_DEFINED 10 11 #include "SkRefCnt.h" 12 #include "SkTypes.h" 13 14 /** 15 * Interface for discardable memory. Implementation is provided by the 16 * embedder. 17 */ 18 class SK_API SkDiscardableMemory { 19 public: 20 /** 21 * Factory method that creates, initializes and locks an SkDiscardableMemory 22 * object. If either of these steps fails, a nullptr pointer will be returned. 23 */ 24 static SkDiscardableMemory* Create(size_t bytes); 25 26 /** 27 * Factory class that creates, initializes and locks an SkDiscardableMemory 28 * object. If either of these steps fails, a nullptr pointer will be returned. 29 */ 30 class Factory : public SkRefCnt { 31 public: 32 virtual SkDiscardableMemory* create(size_t bytes) = 0; 33 private: 34 typedef SkRefCnt INHERITED; 35 }; 36 37 /** Must not be called while locked. 38 */ 39 virtual ~SkDiscardableMemory() {} 40 41 /** 42 * Locks the memory, prevent it from being discarded. Once locked. you may 43 * obtain a pointer to that memory using the data() method. 44 * 45 * lock() may return false, indicating that the underlying memory was 46 * discarded and that the lock failed. 47 * 48 * Nested calls to lock are not allowed. 49 */ 50 virtual bool lock() = 0; 51 52 /** 53 * Returns the current pointer for the discardable memory. This call is ONLY 54 * valid when the discardable memory object is locked. 55 */ 56 virtual void* data() = 0; 57 58 /** 59 * Unlock the memory so that it can be purged by the system. Must be called 60 * after every successful lock call. 61 */ 62 virtual void unlock() = 0; 63 }; 64 65 #endif 66
