[meld] Add get_path_for_repo_file to bzr VC

[Kai Willadsen <kaiw src gnome org>]

commit f3d4f96ffa1147ebf1c65b140804cec25ddd6edc
Author: Louis des Landes <louis obsidian com au>
Date:   Thu Mar 7 13:24:34 2013 +1100

    Add get_path_for_repo_file to bzr VC

 meld/vc/bzr.py |   26 +++++++++++++++++++++++++-
 1 files changed, 25 insertions(+), 1 deletions(-)
---
diff --git a/meld/vc/bzr.py b/meld/vc/bzr.py
index 0e3defa..7cef538 100644
--- a/meld/vc/bzr.py
+++ b/meld/vc/bzr.py
@@ -25,6 +25,9 @@
 import errno
 import os
 import re
+import shutil
+import subprocess
+import tempfile
 
 from . import _vc
 
@@ -152,8 +155,29 @@ class Vc(_vc.CachedVc):
                 retdirs.append( _vc.Dir(path, d, state) )
         return retdirs, retfiles
 
+    def get_path_for_repo_file(self, path, commit=None):
+        if not path.startswith(self.root + os.path.sep):
+            raise _vc.InvalidVCPath(self, path, "Path not in repository")
+
+        path = path[len(self.root) + 1:]
+
+        args = [self.CMD, "cat", path]
+        if commit:
+            args.append("-r%s" % commit)
+        process = subprocess.Popen(args,
+                                   cwd=self.location, stdout=subprocess.PIPE,
+                                   stderr=subprocess.PIPE)
+        vc_file = process.stdout
+
+        # Error handling here involves doing nothing; in most cases, the only
+        # sane response is to return an empty temp file.
+
+        with tempfile.NamedTemporaryFile(prefix='meld-tmp', delete=False) as f:
+            shutil.copyfileobj(vc_file, f)
+        return f.name
+
     def get_path_for_conflict(self, path, conflict):
         if not path.startswith(self.root + os.path.sep):
             raise _vc.InvalidVCPath(self, path, "Path not in repository")
-        
+
         return "%s%s" % (path, self.conflict_map[conflict])