Improvements/additions to SkImageCache/SkLazyPixelRef.

src/lazy/SkLruImageCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLruImageCache.h"
 
 static intptr_t NextGenerationID() {
@@ skipping 56 matching lines @@
 #endif
         SkDELETE(pixels);
         pixels = prev;
     }
 #ifdef SK_DEBUG
     SkASSERT(fRamUsed == 0);
 #endif
 }
 
 #ifdef SK_DEBUG
-SkImageCache::CacheStatus SkLruImageCache::getCacheStatus(intptr_t ID) const {
+SkImageCache::MemoryStatus SkLruImageCache::getMemoryStatus(intptr_t ID) const {
+    if (SkImageCache::UNINITIALIZED_ID == ID) {
+        return SkImageCache::kFreed_MemoryStatus;
+    }
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
     if (NULL == pixels) {
-        return SkImageCache::kThrownAway_CacheStatus;
+        return SkImageCache::kFreed_MemoryStatus;
     }
     if (pixels->isLocked()) {
-        return SkImageCache::kPinned_CacheStatus;
+        return SkImageCache::kPinned_MemoryStatus;
     }
-    return SkImageCache::kUnpinned_CacheStatus;
+    return SkImageCache::kUnpinned_MemoryStatus;
+}
+
+void SkLruImageCache::purgeAllUnpinnedCaches() {
+    SkAutoMutexAcquire ac(&fMutex);
+    this->purgeTilAtOrBelow(0);
 }
 #endif
 
 size_t SkLruImageCache::setImageCacheLimit(size_t newLimit) {
     size_t oldLimit = fRamBudget;
     SkAutoMutexAcquire ac(&fMutex);
     fRamBudget = newLimit;
     this->purgeIfNeeded();
     return oldLimit;
 }
 
 void* SkLruImageCache::allocAndPinCache(size_t bytes, intptr_t* ID) {
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = SkNEW_ARGS(CachedPixels, (bytes));
     if (ID != NULL) {
         *ID = pixels->getID();
     }
     pixels->lock();
     fRamUsed += bytes;
     fLRU.addToHead(pixels);
     this->purgeIfNeeded();
     return pixels->getData();
 }
 
-void* SkLruImageCache::pinCache(intptr_t ID) {
+void* SkLruImageCache::pinCache(intptr_t ID, SkImageCache::DataStatus* status) {
     SkASSERT(ID != SkImageCache::UNINITIALIZED_ID);
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
     if (NULL == pixels) {
         return NULL;
     }
     if (pixels != fLRU.head()) {
         fLRU.remove(pixels);
         fLRU.addToHead(pixels);
     }
+    SkASSERT(status != NULL);
+    // This cache will never return pinned memory whose data has been overwritten.
+    *status = SkImageCache::kRetained_DataStatus;
     pixels->lock();
     return pixels->getData();
 }
 
 void SkLruImageCache::releaseCache(intptr_t ID) {
     SkASSERT(ID != SkImageCache::UNINITIALIZED_ID);
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
     SkASSERT(pixels != NULL);
     pixels->unlock();
     this->purgeIfNeeded();
 }
 
 void SkLruImageCache::throwAwayCache(intptr_t ID) {
+    SkASSERT(ID != SkImageCache::UNINITIALIZED_ID);
     SkAutoMutexAcquire ac(&fMutex);
     CachedPixels* pixels = this->findByID(ID);
     if (pixels != NULL) {
         if (pixels->isLocked()) {
             pixels->unlock();
         }
         this->removePixels(pixels);
     }
 }
 
 void SkLruImageCache::removePixels(CachedPixels* pixels) {
     // Mutex is already locked.
     SkASSERT(!pixels->isLocked());
     const size_t size = pixels->getLength();
     SkASSERT(size <= fRamUsed);
     fLRU.remove(pixels);
     SkDELETE(pixels);
     fRamUsed -= size;
 }
 
 CachedPixels* SkLruImageCache::findByID(intptr_t ID) const {
     // Mutex is already locked.
-    if (SkImageCache::UNINITIALIZED_ID == ID) {
-        return NULL;
-    }
     Iter iter;
     // Start from the head, most recently used.
     CachedPixels* pixels = iter.init(fLRU, Iter::kHead_IterStart);
     while (pixels != NULL) {
         if (pixels->getID() == ID) {
             return pixels;
         }
         pixels = iter.next();
     }
     return NULL;
@@ skipping 14 matching lines @@
         CachedPixels* pixels = iter.init(fLRU, Iter::kTail_IterStart);
         while (pixels != NULL && fRamUsed > limit) {
             CachedPixels* prev = iter.prev();
             if (!pixels->isLocked()) {
                 this->removePixels(pixels);
             }
             pixels = prev;
         }
     }
 }