Throw exception if path can't be watched.

Throw exception if path can't be watched.

BUG=http://code.google.com/p/dart/issues/detail?id=13552
R=zra@google.com

Committed: https://code.google.com/p/dart/source/detail?r=27847

[zra, 2013-09-24 20:08:11]

lgtm

Thanks for the quick fix!

https://codereview.chromium.org/23830014/diff/1/runtime/bin/file_patch.dart
File runtime/bin/file_patch.dart (right):

https://codereview.chromium.org/23830014/diff/1/runtime/bin/file_patch.dart#n...
runtime/bin/file_patch.dart:81: print(socketId);
Is this a leftover debug print?

[Anders Johnsen, 2013-09-24 20:12:31]

https://codereview.chromium.org/23830014/diff/1/runtime/bin/file_patch.dart
File runtime/bin/file_patch.dart (right):

https://codereview.chromium.org/23830014/diff/1/runtime/bin/file_patch.dart#n...
runtime/bin/file_patch.dart:81: print(socketId);
On 2013/09/24 20:08:11, zra wrote:
> Is this a leftover debug print?

Heh, yep, too fast a fix :)

[Anders Johnsen, 2013-09-24 20:13:19]

Committed patchset #2 manually as r27847 (presubmit successful).

[Ivan Posva, 2013-09-24 21:25:07]

-Ivan

https://codereview.chromium.org/23830014/diff/5001/runtime/bin/file_system_wa...
File runtime/bin/file_system_watcher.cc (right):

https://codereview.chromium.org/23830014/diff/5001/runtime/bin/file_system_wa...
runtime/bin/file_system_watcher.cc:38:
Dart_ThrowException(DartUtils::NewDartOSError());
Shouldn't we implement the watching manually by polling instead of just throwing
out to the user code?

[zra, 2013-09-24 21:48:06]

On 2013/09/24 21:25:07, Ivan Posva wrote:
> -Ivan
> 
>
https://codereview.chromium.org/23830014/diff/5001/runtime/bin/file_system_wa...
> File runtime/bin/file_system_watcher.cc (right):
> 
>
https://codereview.chromium.org/23830014/diff/5001/runtime/bin/file_system_wa...
> runtime/bin/file_system_watcher.cc:38:
> Dart_ThrowException(DartUtils::NewDartOSError());
> Shouldn't we implement the watching manually by polling instead of just
throwing
> out to the user code?

Polling in a directory with lots of files could be expensive, but it is probably
preferable to throwing an exception, especially if we can't get something like
inotify working on all platforms. Instead of throwing an exception, we could
bail to an alternate implementation of _listen that polls and adds events to the
list when a change is detected by comparing with some state held in the class.
Maybe the polling frequency, or some filters on files to poll, could be optional
parameters to _listen or the constructor to keep time spent polling under
application control.