diff --git a/git_command.py b/git_command.py
new file mode 100644
index 0000000..a3bd919
--- /dev/null
+++ b/git_command.py
@@ -0,0 +1,164 @@
+#
+# Copyright (C) 2008 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+import sys
+import subprocess
+from error import GitError
+
+GIT = 'git'
+MIN_GIT_VERSION = (1, 5, 4)
+GIT_DIR = 'GIT_DIR'
+REPO_TRACE = 'REPO_TRACE'
+
+LAST_GITDIR = None
+LAST_CWD = None
+try:
+  TRACE = os.environ[REPO_TRACE] == '1'
+except KeyError:
+  TRACE = False
+
+
+class _GitCall(object):
+  def version(self):
+    p = GitCommand(None, ['--version'], capture_stdout=True)
+    if p.Wait() == 0:
+      return p.stdout
+    return None
+
+  def __getattr__(self, name):
+    name = name.replace('_','-')
+    def fun(*cmdv):
+      command = [name]
+      command.extend(cmdv)
+      return GitCommand(None, command).Wait() == 0
+    return fun
+git = _GitCall()
+
+class GitCommand(object):
+  def __init__(self,
+               project,
+               cmdv,
+               bare = False,
+               provide_stdin = False,
+               capture_stdout = False,
+               capture_stderr = False,
+               disable_editor = False,
+               cwd = None,
+               gitdir = None):
+    env = dict(os.environ)
+
+    for e in [REPO_TRACE,
+              GIT_DIR,
+              'GIT_ALTERNATE_OBJECT_DIRECTORIES',
+              'GIT_OBJECT_DIRECTORY',
+              'GIT_WORK_TREE',
+              'GIT_GRAFT_FILE',
+              'GIT_INDEX_FILE']:
+      if e in env:
+        del env[e]
+
+    if disable_editor:
+      env['GIT_EDITOR'] = ':'
+
+    if project:
+      if not cwd:
+        cwd = project.worktree
+      if not gitdir:
+        gitdir = project.gitdir
+
+    command = [GIT]
+    if bare:
+      if gitdir:
+        env[GIT_DIR] = gitdir
+      cwd = None
+    command.extend(cmdv)
+
+    if provide_stdin:
+      stdin = subprocess.PIPE
+    else:
+      stdin = None
+
+    if capture_stdout:
+      stdout = subprocess.PIPE
+    else:
+      stdout = None
+
+    if capture_stderr:
+      stderr = subprocess.PIPE
+    else:
+      stderr = None
+
+    if TRACE:
+      global LAST_CWD
+      global LAST_GITDIR
+
+      dbg = ''
+
+      if cwd and LAST_CWD != cwd:
+        if LAST_GITDIR or LAST_CWD:
+          dbg += '\n'
+        dbg += ': cd %s\n' % cwd
+        LAST_CWD = cwd
+
+      if GIT_DIR in env and LAST_GITDIR != env[GIT_DIR]:
+        if LAST_GITDIR or LAST_CWD:
+          dbg += '\n'
+        dbg += ': export GIT_DIR=%s\n' % env[GIT_DIR]
+        LAST_GITDIR = env[GIT_DIR]
+
+      dbg += ': '
+      dbg += ' '.join(command)
+      if stdin == subprocess.PIPE:
+        dbg += ' 0<|'
+      if stdout == subprocess.PIPE:
+        dbg += ' 1>|'
+      if stderr == subprocess.PIPE:
+        dbg += ' 2>|'
+      print >>sys.stderr, dbg
+
+    try:
+      p = subprocess.Popen(command,
+                           cwd = cwd,
+                           env = env,
+                           stdin = stdin,
+                           stdout = stdout,
+                           stderr = stderr)
+    except Exception, e:
+      raise GitError('%s: %s' % (command[1], e))
+
+    self.process = p
+    self.stdin = p.stdin
+
+  def Wait(self):
+    p = self.process
+
+    if p.stdin:
+      p.stdin.close()
+      self.stdin = None
+
+    if p.stdout:
+      self.stdout = p.stdout.read()
+      p.stdout.close()
+    else:
+      p.stdout = None
+
+    if p.stderr:
+      self.stderr = p.stderr.read()
+      p.stderr.close()
+    else:
+      p.stderr = None
+
+    return self.process.wait()