Only allow one async operation on RandomAccessFile at a time.

Only allow one async operation on RandomAccessFile at a time.

This is to make sure we never have a race-condition on the same
File*/FD. For a File it should be fine, as each operation will open it's
own FD to work on.

BUG=
R=sgjesse@google.com

Committed: https://code.google.com/p/dart/source/detail?r=28088

[Søren Gjesse, 2013-09-26 18:31:19]

We should consider sending out a breaking change notification. As before we
would just queue up all the operations.

https://codereview.chromium.org/24721003/diff/1/sdk/lib/io/file_impl.dart
File sdk/lib/io/file_impl.dart (right):

https://codereview.chromium.org/24721003/diff/1/sdk/lib/io/file_impl.dart#new...
sdk/lib/io/file_impl.dart:856: var msg = "A file operation is already issued for
this RandomAccessFile";
How about a message something like this: "An async operation is currently
pending"?

https://codereview.chromium.org/24721003/diff/1/tests/standalone/io/file_test...
File tests/standalone/io/file_test.dart (right):

https://codereview.chromium.org/24721003/diff/1/tests/standalone/io/file_test...
tests/standalone/io/file_test.dart:1085: static void testDoubleAsyncRead() {
testDoubleAsyncRead -> testDoubleAsyncOperation

[Anders Johnsen, 2013-10-01 10:50:39]

PTAL

https://codereview.chromium.org/24721003/diff/1/sdk/lib/io/file_impl.dart
File sdk/lib/io/file_impl.dart (right):

https://codereview.chromium.org/24721003/diff/1/sdk/lib/io/file_impl.dart#new...
sdk/lib/io/file_impl.dart:856: var msg = "A file operation is already issued for
this RandomAccessFile";
On 2013/09/26 18:31:19, Søren Gjesse wrote:
> How about a message something like this: "An async operation is currently
> pending"?

Done.

https://codereview.chromium.org/24721003/diff/1/tests/standalone/io/file_test...
File tests/standalone/io/file_test.dart (right):

https://codereview.chromium.org/24721003/diff/1/tests/standalone/io/file_test...
tests/standalone/io/file_test.dart:1085: static void testDoubleAsyncRead() {
On 2013/09/26 18:31:19, Søren Gjesse wrote:
> testDoubleAsyncRead -> testDoubleAsyncOperation

Done.

[Søren Gjesse, 2013-10-01 10:52:14]

lgtm

[Anders Johnsen, 2013-10-01 11:23:49]

Committed patchset #2 manually as r28088 (presubmit successful).