This carries a number of benefits:
- It allows the front end to trivially support schemes other than
"file:" (e.g. "http:") by allowing the client to supply a FileSystem
implementation that handles them.
- It is more consistent with the functionality of the ".packages" file
(which allows packages to map to any kind of URI).
- It allows the "bazel root" feature to be rewritten to use a magic
scheme rather than a magic path. (This eliminates concerns about
the magic path overlapping with a user's use case). Note that this
feature has been renamed to "multi root" since it is sufficiently
generic to be applicable to build systems other than Bazel.
- It reduces the risk of forgetting to use the front end's FileSystem
abstraction to access the file system, since the native file system
interfaces do not accept URIs.
R=danrubel@google.com
Review-Url: https://codereview.chromium.org/2614063007 .
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
Review URL: https://codereview.chromium.org/2552383002 .
Paul Berry