Fix a memory leak in SkGPipeCanvas.

In cross process mode (currently unused but tested on the bots),
SkGPipeCanvas has a tangle of circular references, which prevents
it from being deleted. Break the chain of references.

R=junov@chromium.org

Review URL: https://codereview.chromium.org/69633003

git-svn-id: http://skia.googlecode.com/svn/trunk@12237 2bbb7eff-a529-9590-31e7-b0007b416f81
This commit is contained in:
scroggo@google.com 2013-11-12 14:32:38 +00:00
parent d6bea606c6
commit 59c3ab637b

View File

@ -167,33 +167,64 @@ public:
///////////////////////////////////////////////////////////////////////////////
/**
* If SkBitmaps are to be flattened to send to the reader, this class is
* provided to the SkBitmapHeap to tell the SkGPipeCanvas to do so.
*/
class BitmapShuttle : public SkBitmapHeap::ExternalStorage {
public:
BitmapShuttle(SkGPipeCanvas*);
~BitmapShuttle();
virtual bool insert(const SkBitmap& bitmap, int32_t slot) SK_OVERRIDE;
/**
* Remove the SkGPipeCanvas used for insertion. After this, calls to
* insert will crash.
*/
void removeCanvas();
private:
SkGPipeCanvas* fCanvas;
};
///////////////////////////////////////////////////////////////////////////////
class SkGPipeCanvas : public SkCanvas {
public:
SkGPipeCanvas(SkGPipeController*, SkWriter32*, uint32_t flags,
uint32_t width, uint32_t height);
virtual ~SkGPipeCanvas();
void finish() {
if (!fDone) {
if (this->needOpBytes()) {
/**
* Called when nothing else is to be written to the stream. Any repeated
* calls are ignored.
*
* @param notifyReaders Whether to send a message to the reader(s) that
* the writer is through sending commands. Should generally be true,
* unless there is an error which prevents further messages from
* being sent.
*/
void finish(bool notifyReaders) {
if (fDone) {
return;
}
if (notifyReaders && this->needOpBytes()) {
this->writeOp(kDone_DrawOp);
this->doNotify();
if (shouldFlattenBitmaps(fFlags)) {
// In this case, a BitmapShuttle is reffed by the SkBitmapHeap
// and refs this canvas. Unref the SkBitmapHeap to end the
// circular reference. When shouldFlattenBitmaps is false,
// there is no circular reference, so the SkBitmapHeap can be
// safely unreffed in the destructor.
fBitmapHeap->unref();
// This eliminates a similar circular reference (Canvas owns
// the FlattenableHeap which holds a ref to the SkBitmapHeap).
fFlattenableHeap.setBitmapStorage(NULL);
fBitmapHeap = NULL;
}
if (shouldFlattenBitmaps(fFlags)) {
// The following circular references exist:
// fFlattenableHeap -> fWriteBuffer -> fBitmapStorage -> fExternalStorage -> fCanvas
// fBitmapHeap -> fExternalStorage -> fCanvas
// fFlattenableHeap -> fBitmapStorage -> fExternalStorage -> fCanvas
// Break them all by destroying the final link to this SkGPipeCanvas.
fBitmapShuttle->removeCanvas();
}
fDone = true;
}
}
void flushRecording(bool detachCurrentBlock);
size_t freeMemoryIfPossible(size_t bytesToFree);
@ -308,7 +339,9 @@ private:
FlattenableHeap fFlattenableHeap;
FlatDictionary fFlatDictionary;
SkAutoTUnref<BitmapShuttle> fBitmapShuttle;
int fCurrFlatIndex[kCount_PaintFlats];
int flattenToIndex(SkFlattenable* obj, PaintFlats);
// Common code used by drawBitmap*. Behaves differently depending on the
@ -390,24 +423,6 @@ int SkGPipeCanvas::flattenToIndex(SkFlattenable* obj, PaintFlats paintflat) {
///////////////////////////////////////////////////////////////////////////////
/**
* If SkBitmaps are to be flattened to send to the reader, this class is
* provided to the SkBitmapHeap to tell the SkGPipeCanvas to do so.
*/
class BitmapShuttle : public SkBitmapHeap::ExternalStorage {
public:
BitmapShuttle(SkGPipeCanvas*);
~BitmapShuttle();
virtual bool insert(const SkBitmap& bitmap, int32_t slot) SK_OVERRIDE;
private:
SkGPipeCanvas* fCanvas;
};
///////////////////////////////////////////////////////////////////////////////
#define MIN_BLOCK_SIZE (16 * 1024)
#define BITMAPS_TO_KEEP 5
#define FLATTENABLES_TO_KEEP 10
@ -440,9 +455,8 @@ SkGPipeCanvas::SkGPipeCanvas(SkGPipeController* controller,
}
if (shouldFlattenBitmaps(flags)) {
BitmapShuttle* shuttle = SkNEW_ARGS(BitmapShuttle, (this));
fBitmapHeap = SkNEW_ARGS(SkBitmapHeap, (shuttle, BITMAPS_TO_KEEP));
shuttle->unref();
fBitmapShuttle.reset(SkNEW_ARGS(BitmapShuttle, (this)));
fBitmapHeap = SkNEW_ARGS(SkBitmapHeap, (fBitmapShuttle.get(), BITMAPS_TO_KEEP));
} else {
fBitmapHeap = SkNEW_ARGS(SkBitmapHeap,
(BITMAPS_TO_KEEP, controller->numberOfReaders()));
@ -456,7 +470,7 @@ SkGPipeCanvas::SkGPipeCanvas(SkGPipeController* controller,
}
SkGPipeCanvas::~SkGPipeCanvas() {
this->finish();
this->finish(true);
SkSafeUnref(fFactorySet);
SkSafeUnref(fBitmapHeap);
}
@ -474,7 +488,8 @@ bool SkGPipeCanvas::needOpBytes(size_t needed) {
size_t blockSize = SkMax32(MIN_BLOCK_SIZE, needed);
void* block = fController->requestBlock(blockSize, &fBlockSize);
if (NULL == block) {
fDone = true;
// Do not notify the readers, which would call this function again.
this->finish(false);
return false;
}
SkASSERT(SkIsAlign4(fBlockSize));
@ -1179,7 +1194,7 @@ SkCanvas* SkGPipeWriter::startRecording(SkGPipeController* controller, uint32_t
void SkGPipeWriter::endRecording() {
if (fCanvas) {
fCanvas->finish();
fCanvas->finish(true);
fCanvas->unref();
fCanvas = NULL;
}
@ -1211,9 +1226,18 @@ BitmapShuttle::BitmapShuttle(SkGPipeCanvas* canvas) {
}
BitmapShuttle::~BitmapShuttle() {
fCanvas->unref();
this->removeCanvas();
}
bool BitmapShuttle::insert(const SkBitmap& bitmap, int32_t slot) {
SkASSERT(fCanvas != NULL);
return fCanvas->shuttleBitmap(bitmap, slot);
}
void BitmapShuttle::removeCanvas() {
if (NULL == fCanvas) {
return;
}
fCanvas->unref();
fCanvas = NULL;
}