scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame^] | 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 SkLruImageCache_DEFINED |
| 9 | #define SkLruImageCache_DEFINED |
| 10 | |
| 11 | #include "SkImageCache.h" |
| 12 | #include "SkThread.h" |
| 13 | #include "SkTInternalLList.h" |
| 14 | |
| 15 | class CachedPixels; |
| 16 | |
| 17 | /** |
| 18 | * SkImageCache implementation that uses an LRU cache to age out old images. |
| 19 | */ |
| 20 | class SkLruImageCache : public SkImageCache { |
| 21 | |
| 22 | public: |
| 23 | SkLruImageCache(size_t budget); |
| 24 | |
| 25 | virtual ~SkLruImageCache(); |
| 26 | |
| 27 | #ifdef SK_DEBUG |
| 28 | CacheStatus getCacheStatus(intptr_t ID) const SK_OVERRIDE; |
| 29 | #endif |
| 30 | |
| 31 | void setBudget(size_t newBudget); |
| 32 | |
| 33 | virtual void* allocAndPinCache(size_t bytes, intptr_t* ID) SK_OVERRIDE; |
| 34 | virtual void* pinCache(intptr_t ID) SK_OVERRIDE; |
| 35 | virtual void releaseCache(intptr_t ID) SK_OVERRIDE; |
| 36 | virtual void throwAwayCache(intptr_t ID) SK_OVERRIDE; |
| 37 | |
| 38 | private: |
| 39 | // Linked list of recently used. Head is the most recently used, and tail is the least. |
| 40 | SkTInternalLList<CachedPixels> fLRU; |
| 41 | typedef SkTInternalLList<CachedPixels>::Iter Iter; |
| 42 | |
| 43 | #ifdef SK_DEBUG |
| 44 | // fMutex is mutable so that getCacheStatus can be const |
| 45 | mutable |
| 46 | #endif |
| 47 | SkMutex fMutex; |
| 48 | size_t fRamBudget; |
| 49 | size_t fRamUsed; |
| 50 | |
| 51 | /** |
| 52 | * Find the CachedPixels represented by ID, or NULL if not in the cache. Mutex must be locked |
| 53 | * before calling. |
| 54 | */ |
| 55 | CachedPixels* findByID(intptr_t ID) const; |
| 56 | |
| 57 | /** |
| 58 | * If over budget, throw away pixels which are not currently in use until below budget or there |
| 59 | * are no more pixels eligible to be thrown away. Mutex must be locked before calling. |
| 60 | */ |
| 61 | void purgeIfNeeded(); |
| 62 | |
| 63 | /** |
| 64 | * Purge until below limit. Mutex must be locked before calling. |
| 65 | */ |
| 66 | void purgeTilAtOrBelow(size_t limit); |
| 67 | |
| 68 | /** |
| 69 | * Remove a set of CachedPixels. Mutex must be locked before calling. |
| 70 | */ |
| 71 | void removePixels(CachedPixels*); |
| 72 | }; |
| 73 | |
| 74 | #endif // SkLruImageCache_DEFINED |