Copy over git_utils from common and add GitLocalConfig

BUG=skia:5979

# Already ran tryjobs in https://skia-review.googlesource.com/c/4897/11
NOTRY=true
NOTREECHECKS=true
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4897

Change-Id: Iee061101b69b4d1cfb0e640785a19e42c6017ef8
Reviewed-on: https://skia-review.googlesource.com/4897
Commit-Queue: Ravi Mistry <rmistry@google.com>
Reviewed-by: Eric Boren <borenet@google.com>
diff --git a/infra/bots/git_utils.py b/infra/bots/git_utils.py
new file mode 100644
index 0000000..73768f6
--- /dev/null
+++ b/infra/bots/git_utils.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python
+# Copyright (c) 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""This module contains functions for using git."""
+
+import re
+import subprocess
+
+
+class GitLocalConfig(object):
+  """Class to manage local git configs."""
+  def __init__(self, config_dict):
+    self._config_dict = config_dict
+    self._previous_values = {}
+
+  def __enter__(self):
+    for k, v in self._config_dict.iteritems():
+      try:
+        prev = subprocess.check_output(['git', 'config', '--local', k]).rstrip()
+        if prev:
+          self._previous_values[k] = prev
+      except subprocess.CalledProcessError:
+        # We are probably here because the key did not exist in the config.
+        pass
+      subprocess.check_call(['git', 'config', '--local', k, v])
+
+  def __exit__(self, exc_type, _value, _traceback):
+    for k in self._config_dict:
+      if self._previous_values.get(k):
+        subprocess.check_call(
+            ['git', 'config', '--local', k, self._previous_values[k]])
+      else:
+        subprocess.check_call(['git', 'config', '--local', '--unset', k])
+
+
+class GitBranch(object):
+  """Class to manage git branches.
+
+  This class allows one to create a new branch in a repository to make changes,
+  then it commits the changes, switches to master branch, and deletes the
+  created temporary branch upon exit.
+  """
+  def __init__(self, branch_name, commit_msg, upload=True, commit_queue=False,
+               delete_when_finished=True):
+    self._branch_name = branch_name
+    self._commit_msg = commit_msg
+    self._upload = upload
+    self._commit_queue = commit_queue
+    self._patch_set = 0
+    self._delete_when_finished = delete_when_finished
+
+  def __enter__(self):
+    subprocess.check_call(['git', 'reset', '--hard', 'HEAD'])
+    subprocess.check_call(['git', 'checkout', 'master'])
+    if self._branch_name in subprocess.check_output(['git', 'branch']).split():
+      subprocess.check_call(['git', 'branch', '-D', self._branch_name])
+    subprocess.check_call(['git', 'checkout', '-b', self._branch_name,
+                           '-t', 'origin/master'])
+    return self
+
+  def commit_and_upload(self, use_commit_queue=False):
+    """Commit all changes and upload a CL, returning the issue URL."""
+    subprocess.check_call(['git', 'commit', '-a', '-m', self._commit_msg])
+    upload_cmd = ['git', 'cl', 'upload', '-f', '--bypass-hooks',
+                  '--bypass-watchlists']
+    self._patch_set += 1
+    if self._patch_set > 1:
+      upload_cmd.extend(['-t', 'Patch set %d' % self._patch_set])
+    if use_commit_queue:
+      upload_cmd.append('--use-commit-queue')
+    subprocess.check_call(upload_cmd)
+    output = subprocess.check_output(['git', 'cl', 'issue']).rstrip()
+    return re.match('^Issue number: (?P<issue>\d+) \((?P<issue_url>.+)\)$',
+                    output).group('issue_url')
+
+  def __exit__(self, exc_type, _value, _traceback):
+    if self._upload:
+      # Only upload if no error occurred.
+      try:
+        if exc_type is None:
+          self.commit_and_upload(use_commit_queue=self._commit_queue)
+      finally:
+        subprocess.check_call(['git', 'checkout', 'master'])
+        if self._delete_when_finished:
+          subprocess.check_call(['git', 'branch', '-D', self._branch_name])
diff --git a/infra/bots/upload_skps.py b/infra/bots/upload_skps.py
index 2193f34..7d0b079 100644
--- a/infra/bots/upload_skps.py
+++ b/infra/bots/upload_skps.py
@@ -10,10 +10,7 @@
 import subprocess
 import sys
 
-sys.path.insert(0, os.path.join(os.getcwd(), 'common'))
-# pylint:disable=F0401
-from py.utils import git_utils
-
+import git_utils
 
 
 CHROMIUM_SKIA = 'https://chromium.googlesource.com/skia.git'