commit 446a18e7091bdea5c45cba7ade08a311d9956c99
author Dominik Honnef <dominik@honnef.co> Mon Apr 11 20:58:33 2016 +0200
committer Alan Donovan <adonovan@google.com> Wed Apr 13 01:11:48 2016 +0000
tree f3ed5710869cb2082d8d2a5ea1c5d0730ab8f942
parent fb9c7fc43c97e918a21d7be33d10044ed293e438

go/buildutil, cmd/guru: extract overlay context into buildutil

This extracts the overlay context and archive parsing from guru into
buildutil.

At least one tool (gogetdoc) has a vendored copy of this code already,
and more tools implementing the same functionality will follow.

The new code in buildutil is an almost identical copy of the code in
guru (names aside), except for the following changes:

- Instead of reading into a bytes.Buffer, we read directly into a []byte
  of appropriate size

- sameFile first attempts a simple comparison of path.Clean'ed paths.

Change-Id: I97cd978ccc10722e3648e5e10625fa7f1407f202
Reviewed-on: https://go-review.googlesource.com/21805
Reviewed-by: Alan Donovan <adonovan@google.com>