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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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