1 /* 2 * Copyright (C) 2012 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #ifndef ImageDecodingStore_h 27 #define ImageDecodingStore_h 28 29 #include "SkSize.h" 30 #include "SkTypes.h" 31 #include "platform/PlatformExport.h" 32 #include "platform/graphics/DiscardablePixelRef.h" 33 #include "platform/graphics/ScaledImageFragment.h" 34 #include "platform/graphics/skia/SkSizeHash.h" 35 #include "platform/image-decoders/ImageDecoder.h" 36 37 #include "wtf/DoublyLinkedList.h" 38 #include "wtf/HashSet.h" 39 #include "wtf/OwnPtr.h" 40 #include "wtf/PassOwnPtr.h" 41 #include "wtf/ThreadingPrimitives.h" 42 #include "wtf/Vector.h" 43 44 namespace WebCore { 45 46 class ImageFrameGenerator; 47 class SharedBuffer; 48 49 // FUNCTION 50 // 51 // ImageDecodingStore is a class used to manage image cache objects. There are two 52 // types of cache objects stored: 53 // 54 // 1. Image objects 55 // Each image object belongs to one frame decoded and/or resampled from an image 56 // file. The image object can be complete or partial. Complete means the image 57 // is fully decoded and will not mutate in future decoding passes. It can have 58 // multiple concurrent users. A partial image object has only one user. 59 // 60 // 2. Decoder objects 61 // A decoder object contains an image decoder. This allows decoding to resume 62 // from previous states. There can be one user per one decoder object at any 63 // time. 64 // 65 // EXTERNAL OBJECTS 66 // 67 // ScaledImageFragment 68 // A cached image object. Contains the bitmap and information about the bitmap 69 // image. 70 // 71 // ImageDecoder 72 // A decoder object. It is used to decode raw data into bitmap images. 73 // 74 // ImageFrameGenerator 75 // This is a direct user of this cache. Responsible for generating bitmap images 76 // using an ImageDecoder. It contains encoded image data and is used to represent 77 // one image file. It is used to index image and decoder objects in the cache. 78 // 79 // LazyDecodingPixelRef 80 // A read only user of this cache. 81 // 82 // THREAD SAFETY 83 // 84 // All public methods can be used on any thread. 85 86 class PLATFORM_EXPORT ImageDecodingStore { 87 public: 88 static PassOwnPtr<ImageDecodingStore> create() { return adoptPtr(new ImageDecodingStore); } 89 ~ImageDecodingStore(); 90 91 static ImageDecodingStore* instance(); 92 static void initializeOnce(); 93 static void shutdown(); 94 95 // Why do we need this? 96 // ImageDecodingStore is used in two code paths: 97 // 1. Android uses this to cache both images and decoders. 98 // 2. Skia discardable memory path has its own cache. We still want cache 99 // decoders but not images because Skia will take care of it. 100 // Because of the two use cases we want to just disable image caching. 101 // 102 // FIXME: It is weird to have this behavior. We want to remove image 103 // caching from this class once the transition to Skia discardable memory 104 // is complete. 105 static void setImageCachingEnabled(bool); 106 107 // Access a complete cached image object. A complete cached image object is 108 // indexed by the origin (ImageFrameGenerator), scaled size and frame index 109 // within the image file. 110 // Return true if the cache object is found. 111 // Return false if the cache object cannot be found or it is incomplete. 112 bool lockCache(const ImageFrameGenerator*, const SkISize& scaledSize, size_t index, const ScaledImageFragment**); 113 void unlockCache(const ImageFrameGenerator*, const ScaledImageFragment*); 114 const ScaledImageFragment* insertAndLockCache(const ImageFrameGenerator*, PassOwnPtr<ScaledImageFragment>); 115 116 // Access a cached decoder object. A decoder is indexed by origin (ImageFrameGenerator) 117 // and scaled size. Return true if the cached object is found. 118 bool lockDecoder(const ImageFrameGenerator*, const SkISize& scaledSize, ImageDecoder**); 119 void unlockDecoder(const ImageFrameGenerator*, const ImageDecoder*); 120 void insertDecoder(const ImageFrameGenerator*, PassOwnPtr<ImageDecoder>, bool isDiscardable); 121 void removeDecoder(const ImageFrameGenerator*, const ImageDecoder*); 122 123 // Locks the cache for safety, but does not attempt to lock the object we're checking for. 124 bool isCached(const ImageFrameGenerator*, const SkISize& scaledSize, size_t index); 125 126 // Remove all cache entries indexed by ImageFrameGenerator. 127 void removeCacheIndexedByGenerator(const ImageFrameGenerator*); 128 129 void clear(); 130 void setCacheLimitInBytes(size_t); 131 size_t memoryUsageInBytes(); 132 int cacheEntries(); 133 int imageCacheEntries(); 134 int decoderCacheEntries(); 135 136 private: 137 // Image cache entry is identified by: 138 // 1. Pointer to ImageFrameGenerator. 139 // 2. Size of the image. 140 // 3. Frame index. 141 // 4. Frame generation. Increments on each progressive decode. 142 // 143 // The use of generation ID is to allow multiple versions of an image frame 144 // be stored in the cache. Each generation comes from a progressive decode. 145 // 146 // Decoder entries are identified by (1) and (2) only. 147 typedef std::pair<const ImageFrameGenerator*, SkISize> DecoderCacheKey; 148 typedef std::pair<size_t, size_t> IndexAndGeneration; 149 typedef std::pair<DecoderCacheKey, IndexAndGeneration> ImageCacheKey; 150 151 // Base class for all cache entries. 152 class CacheEntry : public DoublyLinkedListNode<CacheEntry> { 153 friend class WTF::DoublyLinkedListNode<CacheEntry>; 154 public: 155 enum CacheType { 156 TypeImage, 157 TypeDecoder, 158 }; 159 160 CacheEntry(const ImageFrameGenerator* generator, int useCount, bool isDiscardable) 161 : m_generator(generator) 162 , m_useCount(useCount) 163 , m_isDiscardable(isDiscardable) 164 , m_prev(0) 165 , m_next(0) 166 { 167 } 168 169 virtual ~CacheEntry() 170 { 171 ASSERT(!m_useCount); 172 } 173 174 const ImageFrameGenerator* generator() const { return m_generator; } 175 int useCount() const { return m_useCount; } 176 void incrementUseCount() { ++m_useCount; } 177 void decrementUseCount() { --m_useCount; ASSERT(m_useCount >= 0); } 178 bool isDiscardable() const { return m_isDiscardable; } 179 180 // FIXME: getSafeSize() returns size in bytes truncated to a 32-bits integer. 181 // Find a way to get the size in 64-bits. 182 virtual size_t memoryUsageInBytes() const = 0; 183 virtual CacheType type() const = 0; 184 185 protected: 186 const ImageFrameGenerator* m_generator; 187 int m_useCount; 188 bool m_isDiscardable; 189 190 private: 191 CacheEntry* m_prev; 192 CacheEntry* m_next; 193 }; 194 195 class ImageCacheEntry : public CacheEntry { 196 public: 197 static PassOwnPtr<ImageCacheEntry> createAndUse(const ImageFrameGenerator* generator, PassOwnPtr<ScaledImageFragment> image) 198 { 199 return adoptPtr(new ImageCacheEntry(generator, 1, image)); 200 } 201 202 ImageCacheEntry(const ImageFrameGenerator* generator, int count, PassOwnPtr<ScaledImageFragment> image) 203 : CacheEntry(generator, count, DiscardablePixelRef::isDiscardable(image->bitmap().pixelRef())) 204 , m_cachedImage(image) 205 { 206 } 207 208 // FIXME: getSafeSize() returns size in bytes truncated to a 32-bits integer. 209 // Find a way to get the size in 64-bits. 210 virtual size_t memoryUsageInBytes() const { return cachedImage()->bitmap().getSafeSize(); } 211 virtual CacheType type() const { return TypeImage; } 212 213 static ImageCacheKey makeCacheKey(const ImageFrameGenerator* generator, const SkISize& size, size_t index, size_t generation) 214 { 215 return std::make_pair(std::make_pair(generator, size), std::make_pair(index, generation)); 216 } 217 ImageCacheKey cacheKey() const { return makeCacheKey(m_generator, m_cachedImage->scaledSize(), m_cachedImage->index(), m_cachedImage->generation()); } 218 const ScaledImageFragment* cachedImage() const { return m_cachedImage.get(); } 219 ScaledImageFragment* cachedImage() { return m_cachedImage.get(); } 220 221 private: 222 OwnPtr<ScaledImageFragment> m_cachedImage; 223 }; 224 225 class DecoderCacheEntry : public CacheEntry { 226 public: 227 static PassOwnPtr<DecoderCacheEntry> create(const ImageFrameGenerator* generator, PassOwnPtr<ImageDecoder> decoder, bool isDiscardable) 228 { 229 return adoptPtr(new DecoderCacheEntry(generator, 0, decoder, isDiscardable)); 230 } 231 232 DecoderCacheEntry(const ImageFrameGenerator* generator, int count, PassOwnPtr<ImageDecoder> decoder, bool isDiscardable) 233 : CacheEntry(generator, count, isDiscardable) 234 , m_cachedDecoder(decoder) 235 , m_size(SkISize::Make(m_cachedDecoder->decodedSize().width(), m_cachedDecoder->decodedSize().height())) 236 { 237 } 238 239 virtual size_t memoryUsageInBytes() const { return m_size.width() * m_size.height() * 4; } 240 virtual CacheType type() const { return TypeDecoder; } 241 242 static DecoderCacheKey makeCacheKey(const ImageFrameGenerator* generator, const SkISize& size) 243 { 244 return std::make_pair(generator, size); 245 } 246 static DecoderCacheKey makeCacheKey(const ImageFrameGenerator* generator, const ImageDecoder* decoder) 247 { 248 return std::make_pair(generator, SkISize::Make(decoder->decodedSize().width(), decoder->decodedSize().height())); 249 } 250 DecoderCacheKey cacheKey() const { return makeCacheKey(m_generator, m_size); } 251 ImageDecoder* cachedDecoder() const { return m_cachedDecoder.get(); } 252 253 private: 254 OwnPtr<ImageDecoder> m_cachedDecoder; 255 SkISize m_size; 256 }; 257 258 ImageDecodingStore(); 259 260 void prune(); 261 262 // These helper methods are called while m_mutex is locked. 263 264 // Find and lock a cache entry, and return true on success. 265 // Memory of the cache entry can be discarded, in which case it is saved in 266 // deletionList. 267 bool lockCacheEntryInternal(ImageCacheEntry*, const ScaledImageFragment**, Vector<OwnPtr<CacheEntry> >* deletionList); 268 269 template<class T, class U, class V> void insertCacheInternal(PassOwnPtr<T> cacheEntry, U* cacheMap, V* identifierMap); 270 271 // Helper method to remove a cache entry. Ownership is transferred to 272 // deletionList. Use of Vector<> is handy when removing multiple entries. 273 template<class T, class U, class V> void removeFromCacheInternal(const T* cacheEntry, U* cacheMap, V* identifierMap, Vector<OwnPtr<CacheEntry> >* deletionList); 274 275 // Helper method to remove a cache entry. Uses the templated version base on 276 // the type of cache entry. 277 void removeFromCacheInternal(const CacheEntry*, Vector<OwnPtr<CacheEntry> >* deletionList); 278 279 // Helper method to remove all cache entries associated with a ImageFraneGenerator. 280 // Ownership of cache entries is transferred to deletionList. 281 template<class U, class V> void removeCacheIndexedByGeneratorInternal(U* cacheMap, V* identifierMap, const ImageFrameGenerator*, Vector<OwnPtr<CacheEntry> >* deletionList); 282 283 // Helper method to remove cache entry pointers from the LRU list. 284 void removeFromCacheListInternal(const Vector<OwnPtr<CacheEntry> >& deletionList); 285 286 // A doubly linked list that maintains usage history of cache entries. 287 // This is used for eviction of old entries. 288 // Head of this list is the least recently used cache entry. 289 // Tail of this list is the most recently used cache entry. 290 DoublyLinkedList<CacheEntry> m_orderedCacheList; 291 292 // A lookup table for all image cache objects. Owns all image cache objects. 293 typedef HashMap<ImageCacheKey, OwnPtr<ImageCacheEntry> > ImageCacheMap; 294 ImageCacheMap m_imageCacheMap; 295 296 // A lookup table for all decoder cache objects. Owns all decoder cache objects. 297 typedef HashMap<DecoderCacheKey, OwnPtr<DecoderCacheEntry> > DecoderCacheMap; 298 DecoderCacheMap m_decoderCacheMap; 299 300 // A lookup table to map ImageFrameGenerator to all associated image 301 // cache keys. 302 typedef HashSet<ImageCacheKey> ImageCacheKeySet; 303 typedef HashMap<const ImageFrameGenerator*, ImageCacheKeySet> ImageCacheKeyMap; 304 ImageCacheKeyMap m_imageCacheKeyMap; 305 306 // A lookup table to map ImageFrameGenerator to all associated 307 // decoder cache keys. 308 typedef HashSet<DecoderCacheKey> DecoderCacheKeySet; 309 typedef HashMap<const ImageFrameGenerator*, DecoderCacheKeySet> DecoderCacheKeyMap; 310 DecoderCacheKeyMap m_decoderCacheKeyMap; 311 312 size_t m_heapLimitInBytes; 313 size_t m_heapMemoryUsageInBytes; 314 size_t m_discardableMemoryUsageInBytes; 315 316 // Protect concurrent access to these members: 317 // m_orderedCacheList 318 // m_imageCacheMap, m_decoderCacheMap and all CacheEntrys stored in it 319 // m_imageCacheKeyMap 320 // m_decoderCacheKeyMap 321 // m_heapLimitInBytes 322 // m_heapMemoryUsageInBytes 323 // m_discardableMemoryUsageInBytes 324 // This mutex also protects calls to underlying skBitmap's 325 // lockPixels()/unlockPixels() as they are not threadsafe. 326 Mutex m_mutex; 327 }; 328 329 } // namespace WebCore 330 331 #endif 332
