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| 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 SkPurgeableMemoryBlock_DEFINED |
| 9 #define SkPurgeableMemoryBlock_DEFINED |
| 10 |
| 11 #include "SkTypes.h" |
| 12 |
| 13 class SkPurgeableMemoryBlock : public SkNoncopyable { |
| 14 |
| 15 public: |
| 16 /** |
| 17 * Whether or not this platform has an implementation for purgeable memory. |
| 18 */ |
| 19 static bool IsSupported(); |
| 20 |
| 21 /** |
| 22 * Create a new purgeable memory block of 'size' bytes. Returns NULL if not
supported on this |
| 23 * platform or on failure. |
| 24 * @param size Number of bytes requested. |
| 25 * @return A new block, or NULL on failure. |
| 26 */ |
| 27 static SkPurgeableMemoryBlock* Create(size_t size); |
| 28 |
| 29 #ifdef SK_DEBUG |
| 30 /** |
| 31 * Whether the platform supports one shot purge of all unpinned blocks. If
so, |
| 32 * PurgeAllUnpinnedBlocks will be used to test a purge. Otherwise, purge wi
ll be called on |
| 33 * individual blocks. |
| 34 */ |
| 35 static bool PlatformSupportsPurgingAllUnpinnedBlocks(); |
| 36 |
| 37 /** |
| 38 * Purge all unpinned blocks at once, if the platform supports it. |
| 39 */ |
| 40 static bool PurgeAllUnpinnedBlocks(); |
| 41 |
| 42 // If PlatformSupportsPurgingAllUnpinnedBlocks returns true, this will not b
e called, so it can |
| 43 // simply return false. |
| 44 bool purge(); |
| 45 |
| 46 bool isPinned() const { return fPinned; } |
| 47 #endif |
| 48 |
| 49 ~SkPurgeableMemoryBlock(); |
| 50 |
| 51 /** |
| 52 * Output parameter for pin(), stating whether the data has been retained. |
| 53 */ |
| 54 enum PinResult { |
| 55 /** |
| 56 * The data has been purged, or this is the first call to pin. |
| 57 */ |
| 58 kUninitialized_PinResult, |
| 59 |
| 60 /** |
| 61 * The data has been retained. The memory contains the same data it hel
d when unpin() was |
| 62 * called. |
| 63 */ |
| 64 kRetained_PinResult, |
| 65 }; |
| 66 |
| 67 /** |
| 68 * Pin the memory for use. Must not be called while already pinned. |
| 69 * @param PinResult Whether the data was retained. Ignored on failure. |
| 70 * @return Pointer to the pinned data on success. NULL on failure. |
| 71 */ |
| 72 void* pin(PinResult*); |
| 73 |
| 74 /** |
| 75 * Unpin the data so it can be purged if necessary. |
| 76 */ |
| 77 void unpin(); |
| 78 |
| 79 private: |
| 80 void* fAddr; |
| 81 size_t fSize; |
| 82 bool fPinned; |
| 83 #ifdef SK_BUILD_FOR_ANDROID |
| 84 int fFD; |
| 85 #endif |
| 86 |
| 87 // Unimplemented default constructor is private, to prevent manual creation. |
| 88 SkPurgeableMemoryBlock(); |
| 89 |
| 90 // The correct way to create a new one is from the static Create. |
| 91 SkPurgeableMemoryBlock(size_t); |
| 92 }; |
| 93 |
| 94 #endif // SkPurgeableMemoryBlock_DEFINED |
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