Change SkStream.

Change SkStream.

[bungeman-skia, 2013-05-20 20:17:08]

This is a proposed change to SkStream to avoid many of the issues we've been
seeing.

Future improvements after something like this lands is to remove SkRefCnt from
SkStream since SkStream is statefull.

The largest current issue is disentangling 'getLength' from 'read'. This change
provides a path to this while keeping the old behavior during the transition.
After all known external implementations of SkStream are updated to the proper
interfaces, we can change our own interfaces to indicate the minimum
capabilities expected of a Stream.

[djsollen, 2013-05-21 15:41:22]

I've only really spent time looking at the SkStream.h header and I have the
following comments.

(1) While we are making changes I vote to add an isEOF() method.

(2) Should we add an query for the stream type that returns the stream type as
an enum?

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h
File include/core/SkStream.h (right):

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h#n...
include/core/SkStream.h:57: virtual void optimize(Optimizer& optimizer) {
optimizer(*this); }
remove the optimizer until we have a demonstrable need.

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h#n...
include/core/SkStream.h:68: //SkStream
remove this

[bungeman-skia, 2013-05-21 23:24:59]

Added atEnd method.

I much prefer the capability based instead of type based queries. I think part
of the issue is alleviated in Patch Set 6 with the hasPosition and hasLength
methods. The abstract types here are more typical collections of capabilities
than what one normally thinks of as a type hierarchy. An 'enum' of the type
would just be a bit field of what was implemented (a getCapabilityFlags method).

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h
File include/core/SkStream.h (right):

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h#n...
include/core/SkStream.h:57: virtual void optimize(Optimizer& optimizer) {
optimizer(*this); }
On 2013/05/21 15:41:22, djsollen wrote:
> remove the optimizer until we have a demonstrable need.

Done.

https://codereview.chromium.org/15298009/diff/21001/include/core/SkStream.h#n...
include/core/SkStream.h:68: //SkStream
On 2013/05/21 15:41:22, djsollen wrote:
> remove this

Done.

[bungeman-skia, 2013-05-28 14:31:46]

Ping.

[reed1, 2013-05-29 12:52:02]

lgtm

[bungeman-skia, 2013-05-29 20:32:06]

Committed revision 9312.