Support imports for dart: libs.

Support imports for dart: libs.

R=smok@google.com

Committed: https://code.google.com/p/dart/source/detail?r=10015

[Roman, 2012-07-30 14:43:29]

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:113: if
(uri.startsWith('dart:')) return true;
you can check the uri scheme, I think, maybe that would be more robust.

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/renamer.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:89: name = "x$name";
Why 'x'? 'x' is an ordinary letter, it will be harder to distinguish prefixed
and original names. I would prefer '_' or some other 'special' character.

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:100: final prefix =
imports.putIfAbsent(library, () => generateUniqueName('p'));
Why 'p' as a prefix? Easier to read would be something like
library.getLibraryOrScriptName()

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:103: if (renamed[element]
!== null) {
Should this check be moved to before generating renamed dart lib prefix? Just to
not calculate the same thing several times.

https://chromiumcodereview.appspot.com/10829076/diff/3001/lib/compiler/implem...
File lib/compiler/implementation/dart_backend/renamer.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/3001/lib/compiler/implem...
lib/compiler/implementation/dart_backend/renamer.dart:101: final prefix =
imports.putIfAbsent(library, () => generateUniqueName('p'));
>80 chars

[Anton Muhin, 2012-07-30 14:54:31]

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:113: if
(uri.startsWith('dart:')) return true;
On 2012/07/30 14:43:30, Roman wrote:
> you can check the uri scheme, I think, maybe that would be more robust.

Do you want me to parse the string and then check the scheme?

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/renamer.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:89: name = "x$name";
Agree, but apparently due to the bug in DartVM, '_p' works poorly as a prefix:
_p.Foo is not resolved :(

I'm going to double check and file a bug.

On 2012/07/30 14:43:30, Roman wrote:
> Why 'x'? 'x' is an ordinary letter, it will be harder to distinguish prefixed
> and original names. I would prefer '_' or some other 'special' character.

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:100: final prefix =
imports.putIfAbsent(library, () => generateUniqueName('p'));
On 2012/07/30 14:43:30, Roman wrote:
> Why 'p' as a prefix? Easier to read would be something like
> library.getLibraryOrScriptName()

I am not sure it's a valid Dart identifier.  Plus it would be just too long.  I
picked p almost randomly (p stands for prefix).

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:103: if (renamed[element]
!== null) {
On 2012/07/30 14:43:30, Roman wrote:
> Should this check be moved to before generating renamed dart lib prefix? Just
to
> not calculate the same thing several times.

Done.

[Roman, 2012-07-30 15:03:42]

lgtm

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/backend.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/backend.dart:113: if
(uri.startsWith('dart:')) return true;
On 2012/07/30 14:54:31, Anton Mukhin wrote:
> On 2012/07/30 14:43:30, Roman wrote:
> > you can check the uri scheme, I think, maybe that would be more robust.
> 
> Do you want me to parse the string and then check the scheme?

Ah sorry, I thought it's a Uri object.

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/renamer.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:89: name = "x$name";
On 2012/07/30 14:54:31, Anton Mukhin wrote:
> Agree, but apparently due to the bug in DartVM, '_p' works poorly as a prefix:
> _p.Foo is not resolved :(
> 
> I'm going to double check and file a bug.
> 
> On 2012/07/30 14:43:30, Roman wrote:
> > Why 'x'? 'x' is an ordinary letter, it will be harder to distinguish
prefixed
> > and original names. I would prefer '_' or some other 'special' character.
> 

That's sad. Maybe '$' ? or anything else?

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:100: final prefix =
imports.putIfAbsent(library, () => generateUniqueName('p'));
On 2012/07/30 14:54:31, Anton Mukhin wrote:
> On 2012/07/30 14:43:30, Roman wrote:
> > Why 'p' as a prefix? Easier to read would be something like
> > library.getLibraryOrScriptName()
> 
> I am not sure it's a valid Dart identifier.  Plus it would be just too long. 
I
> picked p almost randomly (p stands for prefix).

We can fix it if for some reason this will not be an identifier. And, we're not
writing a minifier here, so no need to create identifiers as small as possible,
but it may be very useful for debugging to see the original prefix.

[Anton Muhin, 2012-07-30 15:37:16]

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
File lib/compiler/implementation/dart_backend/renamer.dart (right):

https://chromiumcodereview.appspot.com/10829076/diff/1/lib/compiler/implement...
lib/compiler/implementation/dart_backend/renamer.dart:89: name = "x$name";
On 2012/07/30 15:03:42, Roman wrote:
> On 2012/07/30 14:54:31, Anton Mukhin wrote:
> > Agree, but apparently due to the bug in DartVM, '_p' works poorly as a
prefix:
> > _p.Foo is not resolved :(
> > 
> > I'm going to double check and file a bug.
> > 
> > On 2012/07/30 14:43:30, Roman wrote:
> > > Why 'x'? 'x' is an ordinary letter, it will be harder to distinguish
> prefixed
> > > and original names. I would prefer '_' or some other 'special' character.
> > 
> 
> That's sad. Maybe '$' ? or anything else?

Done.