michael@0: /*
michael@0:  * Copyright 2013 Google Inc.
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: #include "SkCachingPixelRef.h"
michael@0: #include "SkScaledImageCache.h"
michael@0: 
michael@0: bool SkCachingPixelRef::Install(SkImageGenerator* generator,
michael@0:                                 SkBitmap* dst) {
michael@0:     SkImageInfo info;
michael@0:     SkASSERT(dst != NULL);
michael@0:     if ((NULL == generator)
michael@0:         || !(generator->getInfo(&info))
michael@0:         || !dst->setConfig(info, 0)) {
michael@0:         SkDELETE(generator);
michael@0:         return false;
michael@0:     }
michael@0:     SkAutoTUnref<SkCachingPixelRef> ref(SkNEW_ARGS(SkCachingPixelRef,
michael@0:                                            (info, generator, dst->rowBytes())));
michael@0:     dst->setPixelRef(ref);
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: SkCachingPixelRef::SkCachingPixelRef(const SkImageInfo& info,
michael@0:                                      SkImageGenerator* generator,
michael@0:                                      size_t rowBytes)
michael@0:     : INHERITED(info)
michael@0:     , fImageGenerator(generator)
michael@0:     , fErrorInDecoding(false)
michael@0:     , fScaledCacheId(NULL)
michael@0:     , fRowBytes(rowBytes) {
michael@0:     SkASSERT(fImageGenerator != NULL);
michael@0: }
michael@0: SkCachingPixelRef::~SkCachingPixelRef() {
michael@0:     SkDELETE(fImageGenerator);
michael@0:     SkASSERT(NULL == fScaledCacheId);
michael@0:     // Assert always unlock before unref.
michael@0: }
michael@0: 
michael@0: bool SkCachingPixelRef::onNewLockPixels(LockRec* rec) {
michael@0:     if (fErrorInDecoding) {
michael@0:         return false;  // don't try again.
michael@0:     }
michael@0: 
michael@0:     const SkImageInfo& info = this->info();
michael@0:     SkBitmap bitmap;
michael@0:     SkASSERT(NULL == fScaledCacheId);
michael@0:     fScaledCacheId = SkScaledImageCache::FindAndLock(this->getGenerationID(),
michael@0:                                                      info.fWidth,
michael@0:                                                      info.fHeight,
michael@0:                                                      &bitmap);
michael@0:     if (NULL == fScaledCacheId) {
michael@0:         // Cache has been purged, must re-decode.
michael@0:         if ((!bitmap.setConfig(info, fRowBytes)) || !bitmap.allocPixels()) {
michael@0:             fErrorInDecoding = true;
michael@0:             return false;
michael@0:         }
michael@0:         SkAutoLockPixels autoLockPixels(bitmap);
michael@0:         if (!fImageGenerator->getPixels(info, bitmap.getPixels(), fRowBytes)) {
michael@0:             fErrorInDecoding = true;
michael@0:             return false;
michael@0:         }
michael@0:         fScaledCacheId = SkScaledImageCache::AddAndLock(this->getGenerationID(),
michael@0:                                                         info.fWidth,
michael@0:                                                         info.fHeight,
michael@0:                                                         bitmap);
michael@0:         SkASSERT(fScaledCacheId != NULL);
michael@0:     }
michael@0: 
michael@0:     // Now bitmap should contain a concrete PixelRef of the decoded
michael@0:     // image.
michael@0:     SkAutoLockPixels autoLockPixels(bitmap);
michael@0:     void* pixels = bitmap.getPixels();
michael@0:     SkASSERT(pixels != NULL);
michael@0: 
michael@0:     // At this point, the autoLockPixels will unlockPixels()
michael@0:     // to remove bitmap's lock on the pixels.  We will then
michael@0:     // destroy bitmap.  The *only* guarantee that this pointer
michael@0:     // remains valid is the guarantee made by
michael@0:     // SkScaledImageCache that it will not destroy the *other*
michael@0:     // bitmap (SkScaledImageCache::Rec.fBitmap) that holds a
michael@0:     // reference to the concrete PixelRef while this record is
michael@0:     // locked.
michael@0:     rec->fPixels = pixels;
michael@0:     rec->fColorTable = NULL;
michael@0:     rec->fRowBytes = bitmap.rowBytes();
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void SkCachingPixelRef::onUnlockPixels() {
michael@0:     SkASSERT(fScaledCacheId != NULL);
michael@0:     SkScaledImageCache::Unlock( static_cast<SkScaledImageCache::ID*>(fScaledCacheId));
michael@0:     fScaledCacheId = NULL;
michael@0: }