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