[StGIT PATCH 4/4] Compile regexp just once

["Karl Hasselström" <kha@treskal.com>]

It's a waste of time to recompile the same regexp every time we go
through the loop.

Signed-off-by: Karl Hasselström <kha@treskal.com>

---

 stgit/git.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/stgit/git.py b/stgit/git.py
index 1807f69..14b4c81 100644
--- a/stgit/git.py
+++ b/stgit/git.py
@@ -275,8 +275,9 @@ def local_changes(verbose = True):
 
 def get_heads():
     heads = []
+    hr = re.compile(r'^[0-9a-f]{40} refs/heads/(.+)$')
     for line in _output_lines(['git-show-ref', '--heads']):
-        m = re.match('^[0-9a-f]{40} refs/heads/(.+)$', line)
+        m = hr.match(line)
         heads.append(m.group(1))
     return heads