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- /*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "include/core/SkPixelRef.h"
- #include "include/private/SkMutex.h"
- #include "src/core/SkBitmapCache.h"
- #include "src/core/SkNextID.h"
- #include "src/core/SkTraceEvent.h"
- #include <atomic>
- uint32_t SkNextID::ImageID() {
- // We never set the low bit.... see SkPixelRef::genIDIsUnique().
- static std::atomic<uint32_t> nextID{2};
- uint32_t id;
- do {
- id = nextID.fetch_add(2);
- } while (id == 0);
- return id;
- }
- ///////////////////////////////////////////////////////////////////////////////
- SkPixelRef::SkPixelRef(int width, int height, void* pixels, size_t rowBytes)
- : fWidth(width)
- , fHeight(height)
- , fPixels(pixels)
- , fRowBytes(rowBytes)
- , fAddedToCache(false)
- {
- this->needsNewGenID();
- fMutability = kMutable;
- }
- SkPixelRef::~SkPixelRef() {
- this->callGenIDChangeListeners();
- }
- // This is undefined if there are clients in-flight trying to use us
- void SkPixelRef::android_only_reset(int width, int height, size_t rowBytes) {
- fWidth = width;
- fHeight = height;
- fRowBytes = rowBytes;
- // note: we do not change fPixels
- // conservative, since its possible the "new" settings are the same as the old.
- this->notifyPixelsChanged();
- }
- void SkPixelRef::needsNewGenID() {
- fTaggedGenID.store(0);
- SkASSERT(!this->genIDIsUnique()); // This method isn't threadsafe, so the assert should be fine.
- }
- uint32_t SkPixelRef::getGenerationID() const {
- uint32_t id = fTaggedGenID.load();
- if (0 == id) {
- uint32_t next = SkNextID::ImageID() | 1u;
- if (fTaggedGenID.compare_exchange_strong(id, next)) {
- id = next; // There was no race or we won the race. fTaggedGenID is next now.
- } else {
- // We lost a race to set fTaggedGenID. compare_exchange() filled id with the winner.
- }
- // We can't quite SkASSERT(this->genIDIsUnique()). It could be non-unique
- // if we got here via the else path (pretty unlikely, but possible).
- }
- return id & ~1u; // Mask off bottom unique bit.
- }
- void SkPixelRef::addGenIDChangeListener(GenIDChangeListener* listener) {
- if (nullptr == listener || !this->genIDIsUnique()) {
- // No point in tracking this if we're not going to call it.
- delete listener;
- return;
- }
- SkAutoMutexExclusive lock(fGenIDChangeListenersMutex);
- *fGenIDChangeListeners.append() = listener;
- }
- // we need to be called *before* the genID gets changed or zerod
- void SkPixelRef::callGenIDChangeListeners() {
- SkAutoMutexExclusive lock(fGenIDChangeListenersMutex);
- // We don't invalidate ourselves if we think another SkPixelRef is sharing our genID.
- if (this->genIDIsUnique()) {
- for (int i = 0; i < fGenIDChangeListeners.count(); i++) {
- fGenIDChangeListeners[i]->onChange();
- }
- if (fAddedToCache.exchange(false)) {
- SkNotifyBitmapGenIDIsStale(this->getGenerationID());
- }
- }
- // Listeners get at most one shot, so whether these triggered or not, blow them away.
- fGenIDChangeListeners.deleteAll();
- }
- void SkPixelRef::notifyPixelsChanged() {
- #ifdef SK_DEBUG
- if (this->isImmutable()) {
- SkDebugf("========== notifyPixelsChanged called on immutable pixelref");
- }
- #endif
- this->callGenIDChangeListeners();
- this->needsNewGenID();
- }
- void SkPixelRef::setImmutable() {
- fMutability = kImmutable;
- }
- void SkPixelRef::setImmutableWithID(uint32_t genID) {
- /*
- * We are forcing the genID to match an external value. The caller must ensure that this
- * value does not conflict with other content.
- *
- * One use is to force this pixelref's id to match an SkImage's id
- */
- fMutability = kImmutable;
- fTaggedGenID.store(genID);
- }
- void SkPixelRef::setTemporarilyImmutable() {
- SkASSERT(fMutability != kImmutable);
- fMutability = kTemporarilyImmutable;
- }
- void SkPixelRef::restoreMutability() {
- SkASSERT(fMutability != kImmutable);
- fMutability = kMutable;
- }
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