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1 /* |
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2 * Copyright 2013 Google Inc. |
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3 * |
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4 * Use of this source code is governed by a BSD-style license that can be |
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5 * found in the LICENSE file. |
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6 */ |
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7 |
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8 #ifndef SkPurgeableMemoryBlock_DEFINED |
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9 #define SkPurgeableMemoryBlock_DEFINED |
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10 |
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11 #include "SkTypes.h" |
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12 |
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13 class SkPurgeableMemoryBlock : public SkNoncopyable { |
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14 |
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15 public: |
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16 /** |
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17 * Whether or not this platform has an implementation for purgeable memory. |
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18 */ |
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19 static bool IsSupported(); |
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20 |
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21 /** |
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22 * Create a new purgeable memory block of 'size' bytes. Returns NULL if not supported on this |
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23 * platform or on failure. |
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24 * @param size Number of bytes requested. |
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25 * @return A new block, or NULL on failure. |
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26 */ |
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27 static SkPurgeableMemoryBlock* Create(size_t size); |
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28 |
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29 #ifdef SK_DEBUG |
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30 /** |
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31 * Whether the platform supports one shot purge of all unpinned blocks. If so, |
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32 * PurgeAllUnpinnedBlocks will be used to test a purge. Otherwise, purge will be called on |
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33 * individual blocks. |
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34 */ |
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35 static bool PlatformSupportsPurgingAllUnpinnedBlocks(); |
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36 |
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37 /** |
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38 * Purge all unpinned blocks at once, if the platform supports it. |
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39 */ |
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40 static bool PurgeAllUnpinnedBlocks(); |
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41 |
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42 // If PlatformSupportsPurgingAllUnpinnedBlocks returns true, this will not be called, so it can |
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43 // simply return false. |
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44 bool purge(); |
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45 |
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46 bool isPinned() const { return fPinned; } |
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47 #endif |
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48 |
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49 ~SkPurgeableMemoryBlock(); |
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50 |
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51 /** |
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52 * Output parameter for pin(), stating whether the data has been retained. |
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53 */ |
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54 enum PinResult { |
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55 /** |
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56 * The data has been purged, or this is the first call to pin. |
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57 */ |
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58 kUninitialized_PinResult, |
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59 |
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60 /** |
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61 * The data has been retained. The memory contains the same data it held when unpin() was |
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62 * called. |
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63 */ |
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64 kRetained_PinResult, |
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65 }; |
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66 |
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67 /** |
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68 * Pin the memory for use. Must not be called while already pinned. |
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69 * @param PinResult Whether the data was retained. Ignored on failure. |
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70 * @return Pointer to the pinned data on success. NULL on failure. |
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71 */ |
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72 void* pin(PinResult*); |
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73 |
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74 /** |
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75 * Unpin the data so it can be purged if necessary. |
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76 */ |
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77 void unpin(); |
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78 |
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79 private: |
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80 void* fAddr; |
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81 size_t fSize; |
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82 bool fPinned; |
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83 #ifdef SK_BUILD_FOR_ANDROID |
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84 int fFD; |
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85 #endif |
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86 |
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87 // Unimplemented default constructor is private, to prevent manual creation. |
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88 SkPurgeableMemoryBlock(); |
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89 |
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90 // The correct way to create a new one is from the static Create. |
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91 SkPurgeableMemoryBlock(size_t); |
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92 }; |
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93 |
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94 #endif // SkPurgeableMemoryBlock_DEFINED |