gitdir: Add method for getting uncommitted changes

get_uncommitted_changes() is needed for morph status to tell if git
repositories have changes in them.

_get_status() is private, since it does not currently have a user, the
small amount of code in get_uncommitted_changes() wrapping _get_status()
is in the GitDirectory class instead of the branch and merge plugin,
since `morph build` will also need to know about uncommitted changes.

1 files changed, 32 insertions, 0 deletions

diff --git a/morphlib/gitdir.py b/morphlib/gitdir.py
index c075f456..7ee64f36 100644
--- a/morphlib/gitdir.py
+++ b/morphlib/gitdir.py
@@ -16,6 +16,7 @@
 # =*= License: GPL-2 =*=
 
 
+import collections
 import cliapp
 import glob
 import os
@@ -200,6 +201,37 @@ class GitDirectory(object):
         output = self._runcmd(['git', 'rev-parse', '--abbrev-ref', 'HEAD'])
         return output.strip()
 
+    def _get_status(self):
+        '''Runs git status and formats its output into something more useful.
+
+        This runs git status such that unusual filenames are preserved
+        and returns its output in a sequence of (status_code, to_path,
+        from_path).
+
+        from_path is None unless the status_code says there was a rename,
+        in which case it is the path it was renamed from.
+
+        Untracked and ignored changes are also included in the output,
+        their status codes are '??' and '!!' respectively.
+
+        '''
+        status = self._runcmd(['git', 'status', '-z', '--ignored'])
+        tokens = collections.deque(status.split('\0'))
+        while True:
+            tok = tokens.popleft()
+            # Terminates with an empty token, since status ends with a \0
+            if not tok:
+                return
+
+            code = tok[:2]
+            to_path = tok[3:]
+            yield code, to_path, tokens.popleft() if code[0] == 'R' else None
+
+    def get_uncommitted_changes(self):
+        for code, to_path, from_path in self._get_status():
+            if code not in ('??', '!!'):
+                yield code, to_path, from_path
+
 
 def init(dirname):
     '''Initialise a new git repository.'''