Mojo: Fix data pipe ALL_OR_NONE write capacity check.

Mojo: Fix data pipe ALL_OR_NONE write capacity check.

Fixes a bug where ALL_OR_NONE writes to data pipes were checking the
total capacity of the pipe, rather than the available capacity. The bug
allowed ALL_OR_NONE writes to succeed (MOJO_RESULT_OK), but in actuality
only a portion of the data was written.

Updated unit test with a case that fails w/o the fix, but passes with
the fix.

Committed: https://crrev.com/6e49b250ab7a13d62426bb54c348e0a50cd7967a
Cr-Commit-Position: refs/heads/master@{#418929}

[miu, 2016-09-14 22:39:21]

The CQ bit was checked by miu@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-14 22:39:53]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[miu, 2016-09-14 22:40:23]

miu@chromium.org changed reviewers:
+ jam@chromium.org

[miu, 2016-09-14 22:40:23]

jam: PTAL. (I encountered this problem while writing code for my own project
that uses data pipes.)

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_p...
File mojo/edk/system/data_pipe_producer_dispatcher.cc (right):

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_p...
mojo/edk/system/data_pipe_producer_dispatcher.cc:144: return
MOJO_RESULT_OUT_OF_RANGE;
Should this instead be:

1. MOJO_RESULT_SHOULD_WAIT if available_capacity_ is insufficient.
and
2. MOJO_RESULT_OUT_OF_RANGE if options_.capacity_num_bytes is insufficient.

Let me know if I should change this behavior.

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_u...
File mojo/edk/system/data_pipe_unittest.cc (left):

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_u...
mojo/edk/system/data_pipe_unittest.cc:837: /* TODO(jam): enable if we end up
observing max capacity
Not sure what the TODO comment was talking about here, but I resurrected the
commented-out test code. Please advise if there's anything extra you want me to
do here.

[commit-bot: I haz the power, 2016-09-15 00:41:37]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-15 00:41:38]

Dry run: Try jobs failed on following builders:
  linux_android_rel_ng on master.tryserver.chromium.android (JOB_FAILED,
https://build.chromium.org/p/tryserver.chromium.android/builders/linux_androi...)

[jam, 2016-09-15 17:08:34]

lgtm

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_p...
File mojo/edk/system/data_pipe_producer_dispatcher.cc (right):

https://codereview.chromium.org/2341633005/diff/1/mojo/edk/system/data_pipe_p...
mojo/edk/system/data_pipe_producer_dispatcher.cc:144: return
MOJO_RESULT_OUT_OF_RANGE;
On 2016/09/14 22:40:23, miu wrote:
> Should this instead be:
> 
> 1. MOJO_RESULT_SHOULD_WAIT if available_capacity_ is insufficient.
> and
> 2. MOJO_RESULT_OUT_OF_RANGE if options_.capacity_num_bytes is insufficient.
> 
> Let me know if I should change this behavior.

the canonical documentation is in
https://cs.chromium.org/chromium/src/mojo/public/c/system/data_pipe.h?rcl=0&l...,
which says 

"//   |MOJO_RESULT_SHOULD_WAIT| if no data can currently be written (and the
//       consumer is still open) and |flags| does *not* have
//       |MOJO_WRITE_DATA_FLAG_ALL_OR_NONE| set."

so your current implementation is good

[miu, 2016-09-15 18:35:02]

The CQ bit was checked by miu@chromium.org

[commit-bot: I haz the power, 2016-09-15 18:35:43]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-15 19:08:48]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-15 19:10:06]

Description was changed from

==========
Mojo: Fix data pipe ALL_OR_NONE write capacity check.

Fixes a bug where ALL_OR_NONE writes to data pipes were checking the
total capacity of the pipe, rather than the available capacity. The bug
allowed ALL_OR_NONE writes to succeed (MOJO_RESULT_OK), but in actuality
only a portion of the data was written.

Updated unit test with a case that fails w/o the fix, but passes with
the fix.
==========

to

==========
Mojo: Fix data pipe ALL_OR_NONE write capacity check.

Fixes a bug where ALL_OR_NONE writes to data pipes were checking the
total capacity of the pipe, rather than the available capacity. The bug
allowed ALL_OR_NONE writes to succeed (MOJO_RESULT_OK), but in actuality
only a portion of the data was written.

Updated unit test with a case that fails w/o the fix, but passes with
the fix.

Committed: https://crrev.com/6e49b250ab7a13d62426bb54c348e0a50cd7967a
Cr-Commit-Position: refs/heads/master@{#418929}
==========

[commit-bot: I haz the power, 2016-09-15 19:10:07]

Patchset 1 (id:??) landed as
https://crrev.com/6e49b250ab7a13d62426bb54c348e0a50cd7967a
Cr-Commit-Position: refs/heads/master@{#418929}