code review 13708043: go/build: add ctxt.MatchFile

go/build: add ctxt.MatchFile

Fixes issue 6369.

[rsc, 2013-09-13 19:41:13]

Hello dsymonds (cc: golang-dev@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go/

[dsymonds, 2013-09-14 06:17:06]

LGTM

Yours makes it a bit harder to avoid double-reading files in some
situations, but this works for me.

[dsymonds, 2013-09-14 06:17:35]

add "Fixes issue 6369." too.

[r, 2013-09-14 07:17:59]

LGTM

https://codereview.appspot.com/13708043/diff/2001/src/pkg/go/build/build.go
File src/pkg/go/build/build.go (right):

https://codereview.appspot.com/13708043/diff/2001/src/pkg/go/build/build.go#n...
src/pkg/go/build/build.go:417: }
isn't this exactly filepath.Ext?

[rsc, 2013-09-14 15:21:42]

On 2013/09/14 06:17:06, dsymonds wrote:
> LGTM
> 
> Yours makes it a bit harder to avoid double-reading files in some
> situations, but this works for me.

The caller gets to provide the OpenFile function in the Context, so double
reading can certainly be avoided. Also, this way the code can still avoid
opening and reading files it doesn't need to, and it can control how much it
reads.

[rsc, 2013-09-14 15:21:48]

https://codereview.appspot.com/13708043/diff/2001/src/pkg/go/build/build.go
File src/pkg/go/build/build.go (right):

https://codereview.appspot.com/13708043/diff/2001/src/pkg/go/build/build.go#n...
src/pkg/go/build/build.go:417: }
On 2013/09/14 07:17:59, r wrote:
> isn't this exactly filepath.Ext?

It's very close. filepath.Ext knows to ignore any dots before the final slash.
The name here is a single element, not a path, and in fact this code makes no
assumptions about what the path separator is (that information is controlled by
some of the functions in the Context, but there's nothing for this), so I didn't
want to call either filepath.Ext or path.Ext.

[rsc, 2013-09-15 15:29:47]

*** Submitted as https://code.google.com/p/go/source/detail?r=68c78b2f4018 ***

go/build: add ctxt.MatchFile

Fixes issue 6369.

R=dsymonds, r
CC=golang-dev
https://codereview.appspot.com/13708043