Cache the HEAD value

[stgit] / stgit / git.py

diff --git a/stgit/git.py b/stgit/git.py
index 7ab9aef..7a5c9e4 100644 (file)
--- a/stgit/git.py
+++ b/stgit/git.py
@@ -59,7 +59,7 @@ class Commit:
                 self.__author = field[1]
             if field[0] == 'committer':
                 self.__committer = field[1]
-        self.__log = ''.join(lines[i:])
+        self.__log = ''.join(lines[i+1:])
 
     def get_id_hash(self):
         return self.__id_hash
@@ -214,24 +214,36 @@ def local_changes():
     """
     return len(__tree_status()) != 0
 
+# HEAD value cached
+__head = None
+
 def get_head():
-    """Returns a string representing the HEAD
+    """Verifies the HEAD and returns the SHA1 id that represents it
     """
-    return read_string(head_link)
+    global __head
+
+    if not __head:
+        __head = rev_parse('HEAD')
+    return __head
 
 def get_head_file():
     """Returns the name of the file pointed to by the HEAD link
     """
-    # valid link
-    if os.path.islink(head_link) and os.path.isfile(head_link):
-        return os.path.basename(os.readlink(head_link))
-    else:
-        raise GitException, 'Invalid .git/HEAD link. Git tree not initialised?'
+    return os.path.basename(_output_one_line('git-symbolic-ref HEAD'))
 
 def __set_head(val):
     """Sets the HEAD value
     """
-    write_string(head_link, val)
+    global __head
+
+    __head = val
+    if __run('git-update-ref HEAD', [val]) != 0:
+        raise GitException, 'Could not update HEAD to "%s".' % val
+
+def rev_parse(git_id):
+    """Parse the string and return a verified SHA1 id
+    """
+    return _output_one_line(['git-rev-parse', '--verify', git_id])
 
 def add(names):
     """Add the files or recursively add the directory contents
@@ -350,6 +362,15 @@ def commit(message, files = [], parents = [], allowempty = False,
 
     return commit_id
 
+def apply_diff(rev1, rev2):
+    """Apply the diff between rev1 and rev2 onto the current
+    index. This function doesn't need to raise an exception since it
+    is only used for fast-pushing a patch. If this operation fails,
+    the pushing would fall back to the three-way merge.
+    """
+    return os.system('git-diff-tree -p %s %s | git-apply --index 2> /dev/null'
+                     % (rev1, rev2)) == 0
+
 def merge(base, head1, head2):
     """Perform a 3-way merge between base, head1 and head2 into the
     local tree