Make SkStream *not* ref counted.

SkStream is a stateful object, so it does not make sense for it to have
multiple owners. Make SkStream inherit directly from SkNoncopyable.

Update methods which previously called SkStream::ref() (e.g.
SkImageDecoder::buildTileIndex() and SkFrontBufferedStream::Create(),
which required the existing owners to call SkStream::unref()) to take
ownership of their SkStream parameters and delete when done (including
on failure).

Switch all SkAutoTUnref<SkStream>s to SkAutoTDelete<SkStream>s. In some
cases this means heap allocating streams that were previously stack
allocated.

Respect ownership rules of SkTypeface::CreateFromStream() and
SkImageDecoder::buildTileIndex().

Update the comments for exceptional methods which do not affect the
ownership of their SkStream parameters (e.g.
SkPicture::CreateFromStream() and SkTypeface::Deserialize()) to be
explicit about ownership.

Remove test_stream_life, which tested that buildTileIndex() behaved
correctly when SkStream was a ref counted object. The test does not
make sense now that it is not.

In SkPDFStream, remove the SkMemoryStream member. Instead of using it,
create a new SkMemoryStream to pass to fDataStream (which is now an
SkAutoTDelete).

Make other pdf rasterizers behave like SkPDFDocumentToBitmap.

SkPDFDocumentToBitmap delete the SkStream, so do the same in the
following pdf rasterizers:

SkPopplerRasterizePDF
SkNativeRasterizePDF
SkNoRasterizePDF

Requires a change to Android, which currently treats SkStreams as ref
counted objects.

Review URL: https://codereview.chromium.org/849103004

1 files changed, 7 insertions, 10 deletions

diff --git a/include/utils/mac/SkCGUtils.h b/include/utils/mac/SkCGUtils.h
index a0fe666d2c..7ac0431b25 100644
--- a/include/utils/mac/SkCGUtils.h
+++ b/include/utils/mac/SkCGUtils.h
@@ -62,20 +62,17 @@ static inline CGImageRef SkCreateCGImageRef(const SkBitmap& bm) {
  */
 void SkCGDrawBitmap(CGContextRef, const SkBitmap&, float x, float y);
 
+/**
+ *  Create an SkBitmap drawing of the encoded PDF document, returning true on
+ *  success. Deletes the stream when finished.
+ */
 bool SkPDFDocumentToBitmap(SkStream* stream, SkBitmap* output);
 
 /**
- *  Return a provider that wraps the specified stream. It will become an
- *  owner of the stream, so the caller must still manage its ownership.
- *
- *  To hand-off ownership of the stream to the provider, the caller must do
- *  something like the following:
- *
- *  SkStream* stream = new ...;
- *  CGDataProviderRef provider = SkStreamToDataProvider(stream);
- *  stream->unref();
+ *  Return a provider that wraps the specified stream. It will become the only
+ *  owner of the stream, so the caller must stop referring to the stream.
  *
- *  Now when the provider is finally deleted, it will delete the stream.
+ *  When the provider is finally deleted, it will delete the stream.
  */
 CGDataProviderRef SkCreateDataProviderFromStream(SkStream*);