Option for 'repo diff' to generate output suitable for 'patch' cmd

The -u option causes 'repo diff' to generate diff output
with file paths relative to the repository root,
so the output can be applied to the Unix 'patch' command.
The name '-u' was selected for convenience, because
both 'diff' and 'git diff' accept the option with the same name
to generate an 'unified diff' output suitable for 'patch' command.

Change-Id: I79c8356db4ed20ecaccc258b3ba139db76666fe0
Reviewed-on: https://gerrit-review.googlesource.com/34380
Reviewed-by: Shawn Pearce <sop@google.com>
Tested-by: Shawn Pearce <sop@google.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/project.py b/project.py
index 946a6ac3..303abe33 100644
--- a/project.py
+++ b/project.py
@@ -749,7 +749,7 @@ class Project(object):
 
     return 'DIRTY'
 
-  def PrintWorkTreeDiff(self):
+  def PrintWorkTreeDiff(self, absolute_paths=False):
     """Prints the status of the repository to stdout.
     """
     out = DiffColoring(self.config)
@@ -757,6 +757,9 @@ class Project(object):
     if out.is_on:
       cmd.append('--color')
     cmd.append(HEAD)
+    if absolute_paths:
+      cmd.append('--src-prefix=a/%s/' % self.relpath)
+      cmd.append('--dst-prefix=b/%s/' % self.relpath)
     cmd.append('--')
     p = GitCommand(self,
                    cmd,