Make JSON.fuse(UTF8) be more efficient by not creating intermediate string.

Make JSON.fuse(UTF8) be more efficient by not creating intermediate string.

Adds JsonUtf8Encoder class that can be used directly, or through jsonEncoder.fuse(utf8Encoder) or jsonEncoder.startChunkedConversion(_Utf8EncoderSink).

R=sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=41479

[Lasse Reichstein Nielsen, 2014-10-31 09:42:50]

lrn@google.com changed reviewers:
+ sgjesse@google.com

[Søren Gjesse, 2014-11-04 08:26:31]

lgtm

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dart
File sdk/lib/convert/json.dart (right):

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:285: static const int defaultBufferSize = 256;
Isn't this a pretty low default value?

So you are not using DEFAULT_BUFFER_SIZE as the name here?

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:706: writeString('[');
writeCharCode?

ditto below.

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:861: class _JsonUtf8Stringifier extends
_JsonStringifier {
Please add a class comment.

[Lasse Reichstein Nielsen, 2014-11-04 10:25:33]

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dart
File sdk/lib/convert/json.dart (right):

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:285: static const int defaultBufferSize = 256;
It's smallish, but that's good for the cases where you don't need much.
Maybe it should be larger (closer to network frame size perhaps), but it very
much depends on usage.

Suggestions?

I probably should us e DEFAULT_BUFFER_SIZE, for consistency.

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:706: writeString('[');
For an underlying StringBuffer, this is likely to be faster, and for the UTF-8
backend, it should be fairly close in performance.

https://codereview.chromium.org/689043002/diff/20001/sdk/lib/convert/json.dar...
sdk/lib/convert/json.dart:861: class _JsonUtf8Stringifier extends
_JsonStringifier {
On 2014/11/04 08:26:31, Søren Gjesse wrote:
> Please add a class comment.

Done.

[Lasse Reichstein Nielsen, 2014-11-04 10:25:48]

Committed patchset #3 (id:40001) manually as 41479 (presubmit successful).

[sra1, 2014-11-06 17:58:44]

sra@google.com changed reviewers:
+ sra@google.com

[sra1, 2014-11-06 17:58:44]

FYI: This adds 7.5k to CompileAngular-BouncyBalls.
That seems like a lot.