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 | #include "SkLruImageCache.h" |
| 9 | |
| 10 | static intptr_t NextGenerationID() { |
| 11 | static intptr_t gNextID; |
| 12 | do { |
| 13 | gNextID++; |
| 14 | } while (SkImageCache::UNINITIALIZED_ID == gNextID); |
| 15 | return gNextID; |
| 16 | } |
| 17 | |
| 18 | class CachedPixels : public SkNoncopyable { |
| 19 | |
| 20 | public: |
| 21 | CachedPixels(size_t length) |
| 22 | : fLength(length) |
| 23 | , fID(NextGenerationID()) |
| 24 | , fLocked(false) { |
| 25 | fAddr = sk_malloc_throw(length); |
| 26 | } |
| 27 | |
| 28 | ~CachedPixels() { |
| 29 | sk_free(fAddr); |
| 30 | } |
| 31 | |
| 32 | void* getData() { return fAddr; } |
| 33 | |
| 34 | intptr_t getID() const { return fID; } |
| 35 | |
| 36 | size_t getLength() const { return fLength; } |
| 37 | |
| 38 | void lock() { SkASSERT(!fLocked); fLocked = true; } |
| 39 | |
| 40 | void unlock() { SkASSERT(fLocked); fLocked = false; } |
| 41 | |
| 42 | bool isLocked() const { return fLocked; } |
| 43 | |
| 44 | private: |
| 45 | void* fAddr; |
| 46 | size_t fLength; |
| 47 | const intptr_t fID; |
| 48 | bool fLocked; |
| 49 | SK_DECLARE_INTERNAL_LLIST_INTERFACE(CachedPixels); |
| 50 | }; |
| 51 | |
| 52 | //////////////////////////////////////////////////////////////////////////////////// |
| 53 | |
| 54 | SkLruImageCache::SkLruImageCache(size_t budget) |
| 55 | : fRamBudget(budget) |
| 56 | , fRamUsed(0) {} |
| 57 | |
| 58 | SkLruImageCache::~SkLruImageCache() { |
| 59 | // Don't worry about updating pointers. All will be deleted. |
| 60 | Iter iter; |
| 61 | CachedPixels* pixels = iter.init(fLRU, Iter::kTail_IterStart); |
| 62 | while (pixels != NULL) { |
| 63 | CachedPixels* prev = iter.prev(); |
| 64 | SkASSERT(!pixels->isLocked()); |
robertphillips@google.com | ffb91da | 2013-02-25 01:38:01 +0000 | [diff] [blame] | 65 | #ifdef SK_DEBUG |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 66 | fRamUsed -= pixels->getLength(); |
| 67 | #endif |
| 68 | SkDELETE(pixels); |
| 69 | pixels = prev; |
| 70 | } |
robertphillips@google.com | ffb91da | 2013-02-25 01:38:01 +0000 | [diff] [blame] | 71 | #ifdef SK_DEBUG |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 72 | SkASSERT(fRamUsed == 0); |
| 73 | #endif |
| 74 | } |
| 75 | |
| 76 | #ifdef SK_DEBUG |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 77 | SkImageCache::MemoryStatus SkLruImageCache::getMemoryStatus(intptr_t ID) const { |
| 78 | if (SkImageCache::UNINITIALIZED_ID == ID) { |
| 79 | return SkImageCache::kFreed_MemoryStatus; |
| 80 | } |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 81 | SkAutoMutexAcquire ac(&fMutex); |
| 82 | CachedPixels* pixels = this->findByID(ID); |
| 83 | if (NULL == pixels) { |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 84 | return SkImageCache::kFreed_MemoryStatus; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 85 | } |
| 86 | if (pixels->isLocked()) { |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 87 | return SkImageCache::kPinned_MemoryStatus; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 88 | } |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 89 | return SkImageCache::kUnpinned_MemoryStatus; |
| 90 | } |
| 91 | |
| 92 | void SkLruImageCache::purgeAllUnpinnedCaches() { |
| 93 | SkAutoMutexAcquire ac(&fMutex); |
| 94 | this->purgeTilAtOrBelow(0); |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 95 | } |
| 96 | #endif |
| 97 | |
scroggo@google.com | a560d00b | 2013-03-04 21:32:32 +0000 | [diff] [blame] | 98 | size_t SkLruImageCache::setImageCacheLimit(size_t newLimit) { |
| 99 | size_t oldLimit = fRamBudget; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 100 | SkAutoMutexAcquire ac(&fMutex); |
scroggo@google.com | a560d00b | 2013-03-04 21:32:32 +0000 | [diff] [blame] | 101 | fRamBudget = newLimit; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 102 | this->purgeIfNeeded(); |
scroggo@google.com | a560d00b | 2013-03-04 21:32:32 +0000 | [diff] [blame] | 103 | return oldLimit; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 104 | } |
| 105 | |
| 106 | void* SkLruImageCache::allocAndPinCache(size_t bytes, intptr_t* ID) { |
| 107 | SkAutoMutexAcquire ac(&fMutex); |
| 108 | CachedPixels* pixels = SkNEW_ARGS(CachedPixels, (bytes)); |
| 109 | if (ID != NULL) { |
| 110 | *ID = pixels->getID(); |
| 111 | } |
| 112 | pixels->lock(); |
| 113 | fRamUsed += bytes; |
| 114 | fLRU.addToHead(pixels); |
| 115 | this->purgeIfNeeded(); |
| 116 | return pixels->getData(); |
| 117 | } |
| 118 | |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 119 | void* SkLruImageCache::pinCache(intptr_t ID, SkImageCache::DataStatus* status) { |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 120 | SkASSERT(ID != SkImageCache::UNINITIALIZED_ID); |
| 121 | SkAutoMutexAcquire ac(&fMutex); |
| 122 | CachedPixels* pixels = this->findByID(ID); |
| 123 | if (NULL == pixels) { |
| 124 | return NULL; |
| 125 | } |
| 126 | if (pixels != fLRU.head()) { |
| 127 | fLRU.remove(pixels); |
| 128 | fLRU.addToHead(pixels); |
| 129 | } |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 130 | SkASSERT(status != NULL); |
| 131 | // This cache will never return pinned memory whose data has been overwritten. |
| 132 | *status = SkImageCache::kRetained_DataStatus; |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 133 | pixels->lock(); |
| 134 | return pixels->getData(); |
| 135 | } |
| 136 | |
| 137 | void SkLruImageCache::releaseCache(intptr_t ID) { |
| 138 | SkASSERT(ID != SkImageCache::UNINITIALIZED_ID); |
| 139 | SkAutoMutexAcquire ac(&fMutex); |
| 140 | CachedPixels* pixels = this->findByID(ID); |
| 141 | SkASSERT(pixels != NULL); |
| 142 | pixels->unlock(); |
| 143 | this->purgeIfNeeded(); |
| 144 | } |
| 145 | |
| 146 | void SkLruImageCache::throwAwayCache(intptr_t ID) { |
scroggo@google.com | bb281f7 | 2013-03-18 21:37:39 +0000 | [diff] [blame] | 147 | SkASSERT(ID != SkImageCache::UNINITIALIZED_ID); |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 148 | SkAutoMutexAcquire ac(&fMutex); |
| 149 | CachedPixels* pixels = this->findByID(ID); |
| 150 | if (pixels != NULL) { |
| 151 | if (pixels->isLocked()) { |
| 152 | pixels->unlock(); |
| 153 | } |
| 154 | this->removePixels(pixels); |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | void SkLruImageCache::removePixels(CachedPixels* pixels) { |
| 159 | // Mutex is already locked. |
| 160 | SkASSERT(!pixels->isLocked()); |
| 161 | const size_t size = pixels->getLength(); |
| 162 | SkASSERT(size <= fRamUsed); |
| 163 | fLRU.remove(pixels); |
| 164 | SkDELETE(pixels); |
| 165 | fRamUsed -= size; |
| 166 | } |
| 167 | |
| 168 | CachedPixels* SkLruImageCache::findByID(intptr_t ID) const { |
| 169 | // Mutex is already locked. |
| 170 | Iter iter; |
| 171 | // Start from the head, most recently used. |
| 172 | CachedPixels* pixels = iter.init(fLRU, Iter::kHead_IterStart); |
| 173 | while (pixels != NULL) { |
| 174 | if (pixels->getID() == ID) { |
| 175 | return pixels; |
| 176 | } |
| 177 | pixels = iter.next(); |
| 178 | } |
| 179 | return NULL; |
| 180 | } |
| 181 | |
| 182 | void SkLruImageCache::purgeIfNeeded() { |
| 183 | // Mutex is already locked. |
scroggo@google.com | a560d00b | 2013-03-04 21:32:32 +0000 | [diff] [blame] | 184 | if (fRamBudget > 0) { |
| 185 | this->purgeTilAtOrBelow(fRamBudget); |
| 186 | } |
scroggo@google.com | f8d7d27 | 2013-02-22 21:38:35 +0000 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | void SkLruImageCache::purgeTilAtOrBelow(size_t limit) { |
| 190 | // Mutex is already locked. |
| 191 | if (fRamUsed > limit) { |
| 192 | Iter iter; |
| 193 | // Start from the tail, least recently used. |
| 194 | CachedPixels* pixels = iter.init(fLRU, Iter::kTail_IterStart); |
| 195 | while (pixels != NULL && fRamUsed > limit) { |
| 196 | CachedPixels* prev = iter.prev(); |
| 197 | if (!pixels->isLocked()) { |
| 198 | this->removePixels(pixels); |
| 199 | } |
| 200 | pixels = prev; |
| 201 | } |
| 202 | } |
| 203 | } |