Add an async version of dependency_walker.dart.

Add an async version of dependency_walker.dart.

This is intended to be used in situations where computing dependencies
and/or evaluating nodes is an asynchronous operation.  (For example,
when performing a compilation, computing dependencies of a library
requires file I/O to read the files constituting the library;
evaluating a library cycle might potentially be performed
asynchronously by a separate isolate).

At the moment the implementation is nearly the same as that of
dependency_walker.dart, except asynchronous.  In future CLs I will
look into allowing computeDependencies(), evaluate(), and
evaluateScc() to operate in parallel.

R=scheglov@google.com

Committed: https://github.com/dart-lang/sdk/commit/4ee949c154312e2a44f4351377cdcf021c2cf176

[Paul Berry, 2016-12-06 19:18:06]

paulberry@google.com changed reviewers:
+ scheglov@google.com

[scheglov, 2016-12-06 19:24:15]

LGTM

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/lib/src/async...
File pkg/front_end/lib/src/async_dependency_walker.dart (right):

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/lib/src/async...
pkg/front_end/lib/src/async_dependency_walker.dart:18: Future evaluate(NodeType
v);
Would Future<Null> be better here and below as a replacement for "void"?

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/test/src/asyn...
File pkg/front_end/test/src/async_dependency_walker_test.dart (right):

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/test/src/asyn...
pkg/front_end/test/src/async_dependency_walker_test.dart:44: Future
test_complex_graph() async {
For tests I usually don't specify the Future return type.
It's OK it keep it too thought.
Just curious if there is a benefit.

[Paul Berry, 2016-12-06 20:28:45]

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/lib/src/async...
File pkg/front_end/lib/src/async_dependency_walker.dart (right):

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/lib/src/async...
pkg/front_end/lib/src/async_dependency_walker.dart:18: Future evaluate(NodeType
v);
On 2016/12/06 19:24:14, scheglov wrote:
> Would Future<Null> be better here and below as a replacement for "void"?

Done.

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/test/src/asyn...
File pkg/front_end/test/src/async_dependency_walker_test.dart (right):

https://codereview.chromium.org/2552383002/diff/1/pkg/front_end/test/src/asyn...
pkg/front_end/test/src/async_dependency_walker_test.dart:44: Future
test_complex_graph() async {
On 2016/12/06 19:24:14, scheglov wrote:
> For tests I usually don't specify the Future return type.
> It's OK it keep it too thought.
> Just curious if there is a benefit.

No benefit I'm aware of.  I went ahead and removed them.

[Paul Berry, 2016-12-06 20:29:11]

Description was changed from

==========
Add an async version of dependency_walker.dart.

This is intended to be used in situations where computing dependencies
and/or evaluating nodes is an asynchronous operation.  (For example,
when performing a compilation, computing dependencies of a library
requires file I/O to read the files constituting the library;
evaluating a library cycle might potentially be performed
asynchronously by a separate isolate).

At the moment the implementation is nearly the same as that of
dependency_walker.dart, except asynchronous.  In future CLs I will
look into allowing computeDependencies(), evaluate(), and
evaluateScc() to operate in parallel.
==========

to

==========
Add an async version of dependency_walker.dart.

This is intended to be used in situations where computing dependencies
and/or evaluating nodes is an asynchronous operation.  (For example,
when performing a compilation, computing dependencies of a library
requires file I/O to read the files constituting the library;
evaluating a library cycle might potentially be performed
asynchronously by a separate isolate).

At the moment the implementation is nearly the same as that of
dependency_walker.dart, except asynchronous.  In future CLs I will
look into allowing computeDependencies(), evaluate(), and
evaluateScc() to operate in parallel.

R=scheglov@google.com

Committed:
https://github.com/dart-lang/sdk/commit/4ee949c154312e2a44f4351377cdcf021c2cf176
==========

[Paul Berry, 2016-12-06 20:29:12]

Committed patchset #1 (id:1) manually as
4ee949c154312e2a44f4351377cdcf021c2cf176 (presubmit successful).