Add lots of utils, PRESUBMIT.py

py/utils/misc.py

Index: py/utils/misc.py
diff --git a/py/utils/misc.py b/py/utils/misc.py
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+++ b/py/utils/misc.py
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+#!/usr/bin/env python
+# Copyright (c) 2012 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 miscellaneous tools used by the buildbot scripts. """
+
+import os
+
+from git_utils import GIT
+import shell_utils
+
+
+# Absolute path to the root of this Skia buildbot checkout.
+BUILDBOT_PATH = os.path.realpath(os.path.join(
+    os.path.dirname(os.path.abspath(__file__)),
+    os.pardir, os.pardir, os.pardir))
+
+
+def ArgsToDict(argv):
+  """ Collect command-line arguments of the form '--key value' into a
+  dictionary.  Fail if the arguments do not fit this format. """
+  dictionary = {}
+  PREFIX = '--'
+  # Expect the first arg to be the path to the script, which we don't want.
+  argv = argv[1:]
+  while argv:
+    if argv[0].startswith(PREFIX):
+      dictionary[argv[0][len(PREFIX):]] = argv[1]
+      argv = argv[2:]
+    else:
+      raise Exception('Malformed input: %s' % argv)
+  return dictionary
+
+
+def ConfirmOptionsSet(name_value_dict):
+  """Raise an exception if any of the given command-line options were not set.
+
+  name_value_dict: dictionary mapping option names to option values
+  """
+  for (name, value) in name_value_dict.iteritems():
+    if value is None:
+      raise Exception('missing command-line option %s; rerun with --help' %
+                      name)
+
+
+def GetAbsPath(relative_path):
+  """My own implementation of os.path.abspath() that better handles paths
+  which approach Window's 260-character limit.
+  See https://code.google.com/p/skia/issues/detail?id=674
+
+  This implementation adds path components one at a time, resolving the
+  absolute path each time, to take advantage of any chdirs into outer
+  directories that will shorten the total path length.
+
+  TODO(epoger): share a single implementation with bench_graph_svg.py, instead
+  of pasting this same code into both files."""
+  if os.path.isabs(relative_path):
+    return relative_path
+  path_parts = relative_path.split(os.sep)
+  abs_path = os.path.abspath('.')
+  for path_part in path_parts:
+    abs_path = os.path.abspath(os.path.join(abs_path, path_part))
+  return abs_path
+
+
+class ChDir(object):
+  """Enter and exit the given directory appropriately."""
+
+  def __init__(self, directory):
+    """Instantiate the ChDir.
+
+    Args:
+        directory: string; the directory to enter.
+    """
+    self._destination = directory
+    self._origin = None
+
+  def __enter__(self):
+    """Change to the destination directory.
+
+    Does not check whether the directory exists.
+    """
+    self._origin = os.getcwd()
+    print 'chdir %s' % self._destination
+    os.chdir(self._destination)
+
+  def __exit__(self, *args):
+    """Change back to the original directory."""
+    print 'chdir %s' % self._origin
+    os.chdir(self._origin)
+
+
+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):
+    self._branch_name = branch_name
+    self._commit_msg = commit_msg
+    self._upload = upload
+    self._commit_queue = commit_queue
+    self._patch_set = 0
+
+  def __enter__(self):
+    shell_utils.run([GIT, 'reset', '--hard', 'HEAD'])
+    shell_utils.run([GIT, 'checkout', 'master'])
+    if self._branch_name in shell_utils.run([GIT, 'branch']):
+      shell_utils.run([GIT, 'branch', '-D', self._branch_name])
+    shell_utils.run([GIT, 'checkout', '-b', self._branch_name,
+                     '-t', 'origin/master'])
+    return self
+
+  def commit_and_upload(self, use_commit_queue=False):
+    shell_utils.run([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')
+    shell_utils.run(upload_cmd)
+
+  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:
+        shell_utils.run([GIT, 'checkout', 'master'])
+        shell_utils.run([GIT, 'branch', '-D', self._branch_name])
+