(Fix #215) better error printing in editor & extension, adds mapping for editor

(Fix #215) better error printing in editor & extension, adds mapping for editor

This change:
- adds json formatted output for the Dart editor to show messages,
- changes how we print messages so we can forward messages from the background
  extension page, back to the main page
- prints the mapping message so the Dart editor can redirect launched files.

Committed: https://github.com/dart-lang/dart-web-components/commit/fe77828

[Jennifer Messerly, 2012-12-06 04:00:08]

https://chromiumcodereview.appspot.com/11450020/diff/6009/bin/dwc_browser.dart
File bin/dwc_browser.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/bin/dwc_browser.dar...
bin/dwc_browser.dart:54: js.context.proxyMessages(sourcePagePort,
out of curiousity, can you inline proxyMessages?

sourcePagePort.postMessage(js.map({'type': 'MESSAGES', 'messages':
messages.messages.map((m) => '$m')}));

https://chromiumcodereview.appspot.com/11450020/diff/6009/extension/content_s...
File extension/content_script.js (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/extension/content_s...
extension/content_script.js:67: window.console.log(messages[i]);
console.warn, console.error?

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart
File lib/dwc.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart#newcode76
lib/dwc.dart:76: _printMessages(messages, options);
Messages should be printed as we emit them, not all at once at the end.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart#newcod...
lib/dwc.dart:109: for (var message in messages.messages) {
verbose messages are always printed now?

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.dart
File lib/src/messages.dart (left):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.da...
lib/src/messages.dart:68: final PrintHandler printHandler;
I think we should keep printHandler, so we can print messages as we go.

It would be fine to change the details though. i.e. it could be required, or it
could be an enum instead of a function (with 3 options -- don't print, print to
JSON, print normally).

Actually, could we derive this information from CompilerOptions? And if
CompilerOptions is not passed -- we're in silent mode (for tests)

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.dart
File lib/src/messages.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.da...
lib/src/messages.dart:68: 'line': span.line + 1,
Not all messages have a span. IIRC, info messages and failure to open a file do
not usually have it.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/options.dart
File lib/src/options.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/options.dar...
lib/src/options.dart:70: ..addFlag('json_format', abbr: 'j',
I dunno if this one really needs a short option -- it's pretty advanced.
Presumably only passed when we're debugging build.dart

[Siggi Cherem (dart-lang), 2012-12-06 18:46:42]

https://chromiumcodereview.appspot.com/11450020/diff/6009/bin/dwc_browser.dart
File bin/dwc_browser.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/bin/dwc_browser.dar...
bin/dwc_browser.dart:54: js.context.proxyMessages(sourcePagePort,
On 2012/12/06 04:00:08, John Messerly wrote:
> out of curiousity, can you inline proxyMessages?
> 
> sourcePagePort.postMessage(js.map({'type': 'MESSAGES', 'messages':
> messages.messages.map((m) => '$m')}));

yes, I believe so, I wasn't sure if 'map' worked ok, but I think it does. Here I
just wanted to follow the pattern Jacob started by adding some abstraction from
the background.js file.

https://chromiumcodereview.appspot.com/11450020/diff/6009/extension/content_s...
File extension/content_script.js (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/extension/content_s...
extension/content_script.js:67: window.console.log(messages[i]);
On 2012/12/06 04:00:08, John Messerly wrote:
> console.warn, console.error?

ohhh... didn't know we had those :)

Done.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart
File lib/dwc.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart#newcode76
lib/dwc.dart:76: _printMessages(messages, options);
On 2012/12/06 04:00:08, John Messerly wrote:
> Messages should be printed as we emit them, not all at once at the end.

I don't necessarily agree, but I think I might be missing some details. Let's
chat about it in person.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/dwc.dart#newcod...
lib/dwc.dart:109: for (var message in messages.messages) {
On 2012/12/06 04:00:08, John Messerly wrote:
> verbose messages are always printed now?

Fixed.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.dart
File lib/src/messages.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/messages.da...
lib/src/messages.dart:68: 'line': span.line + 1,
On 2012/12/06 04:00:08, John Messerly wrote:
> Not all messages have a span. IIRC, info messages and failure to open a file
do
> not usually have it.

good point - this made me realize that we have places where we don't even have a
file associated with the error (e.g. you provide bad path information on the
command line.)

Some of those errors can also be present if you have an incorrect build.dart, I
wonder if we should report those errors in the build.dart file location.

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/options.dart
File lib/src/options.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/6009/lib/src/options.dar...
lib/src/options.dart:70: ..addFlag('json_format', abbr: 'j',
On 2012/12/06 04:00:08, John Messerly wrote:
> I dunno if this one really needs a short option -- it's pretty advanced.
> Presumably only passed when we're debugging build.dart

Done.

[Siggi Cherem (dart-lang), 2012-12-06 19:56:54]

PTAL - switched back to print errors as soon as we find them, except for the
extension, that sends them all at the end.

[Jennifer Messerly, 2012-12-06 19:59:54]

lgtm. the errors/warnings in the web inspector console is awesome :)

https://chromiumcodereview.appspot.com/11450020/diff/17002/lib/src/messages.dart
File lib/src/messages.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/17002/lib/src/messages.d...
lib/src/messages.dart:108: if (shouldPrint) {
Put this in a helper function?
(since we had that bug once where the code paths got out of sync :) )

[Siggi Cherem (dart-lang), 2012-12-06 20:03:14]

https://chromiumcodereview.appspot.com/11450020/diff/17002/lib/src/messages.dart
File lib/src/messages.dart (right):

https://chromiumcodereview.appspot.com/11450020/diff/17002/lib/src/messages.d...
lib/src/messages.dart:108: if (shouldPrint) {
On 2012/12/06 19:59:54, John Messerly wrote:
> Put this in a helper function?
> (since we had that bug once where the code paths got out of sync :) )

Done.