depot_tools: import bot_update gclient git rietveld tryserver recipe modules (reland #1)

recipe_modules/bot_update/resources/bot_update.py

+#!/usr/bin/env python
+# Copyright 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.
+
+# TODO(hinoka): Use logging.
+
+import cStringIO
+import codecs
+import collections
+import copy
+import ctypes
+import json
+import optparse
+import os
+import pprint
+import random
+import re
+import socket
+import subprocess
+import sys
+import tempfile
+import threading
+import time
+import urllib2
+import urlparse
+import uuid
+
+import os.path as path
+
+# How many bytes at a time to read from pipes.
+BUF_SIZE = 256
+
+
+# TODO(luqui): This is a horrible hack to identify build_internal when build
+# is a recipe dependency.  bot_update should not be depending on internal,
+# rather the arrow should go the other way (or just be destroyed).
+def check_dir(name, dirs, default=None):
+  for d in dirs:
+    d = path.abspath(d)
+    if path.basename(d) == name and path.isdir(d):
+      return d
+  return default
+
+
+# Define a bunch of directory paths.
+# Relative to the current working directory.
+CURRENT_DIR = path.abspath(os.getcwd())
+BUILDER_DIR = path.dirname(CURRENT_DIR)
+SLAVE_DIR = path.dirname(BUILDER_DIR)
+
+# Relative to this script's filesystem path.
+THIS_DIR = path.dirname(path.abspath(__file__))
+SCRIPTS_DIR = check_dir(
+    'scripts', [
+        path.dirname(THIS_DIR),
+        path.join(SLAVE_DIR, '..', 'scripts'),
+    ], default=path.dirname(THIS_DIR))
+BUILD_DIR = path.dirname(SCRIPTS_DIR)
+ROOT_DIR = path.dirname(BUILD_DIR)
+
+DEPOT_TOOLS_DIR = path.abspath(path.join(THIS_DIR, '..', '..', '..'))
+
+BUILD_INTERNAL_DIR = check_dir(
+    'build_internal', [
+        path.join(ROOT_DIR, 'build_internal'),
+        path.join(ROOT_DIR,      # .recipe_deps
+                  path.pardir,   # slave
+                  path.pardir,   # scripts
+                  path.pardir),  # build_internal
+    ])
+
+
+CHROMIUM_GIT_HOST = 'https://chromium.googlesource.com'
+CHROMIUM_SRC_URL = CHROMIUM_GIT_HOST + '/chromium/src.git'
+
+# Official builds use buildspecs, so this is a special case.
+BUILDSPEC_TYPE = collections.namedtuple('buildspec',
+    ('container', 'version'))
+BUILDSPEC_RE = (r'^/chrome-internal/trunk/tools/buildspec/'
+                 '(build|branches|releases)/(.+)$')
+GIT_BUILDSPEC_PATH = ('https://chrome-internal.googlesource.com/chrome/tools/'
+                      'buildspec')
+BRANCH_HEADS_REFSPEC = '+refs/branch-heads/*'
+
+BUILDSPEC_COMMIT_RE = (
+    re.compile(r'Buildspec for.*version (\d+\.\d+\.\d+\.\d+)'),
+    re.compile(r'Create (\d+\.\d+\.\d+\.\d+) buildspec'),
+    re.compile(r'Auto-converted (\d+\.\d+\.\d+\.\d+) buildspec to git'),
+)
+
+# Regular expression that matches a single commit footer line.
+COMMIT_FOOTER_ENTRY_RE = re.compile(r'([^:]+):\s+(.+)')
+
+# Footer metadata keys for regular and gsubtreed mirrored commit positions.
+COMMIT_POSITION_FOOTER_KEY = 'Cr-Commit-Position'
+COMMIT_ORIGINAL_POSITION_FOOTER_KEY = 'Cr-Original-Commit-Position'
+# Regular expression to parse a commit position
+COMMIT_POSITION_RE = re.compile(r'(.+)@\{#(\d+)\}')
+
+# Regular expression to parse gclient's revinfo entries.
+REVINFO_RE = re.compile(r'^([^:]+):\s+([^@]+)@(.+)$')
+
+# Used by 'ResolveSvnRevisionFromGitiles'
+GIT_SVN_PROJECT_MAP = {
+  'webkit': {
+    'svn_url': 'svn://svn.chromium.org/blink',
+    'branch_map': [
+      (r'trunk', r'refs/heads/master'),
+      (r'branches/([^/]+)', r'refs/branch-heads/\1'),
+    ],
+  },
+  'v8': {
+    'svn_url': 'https://v8.googlecode.com/svn',
+    'branch_map': [
+      (r'trunk', r'refs/heads/candidates'),
+      (r'branches/bleeding_edge', r'refs/heads/master'),
+      (r'branches/([^/]+)', r'refs/branch-heads/\1'),
+    ],
+  },
+  'nacl': {
+    'svn_url': 'svn://svn.chromium.org/native_client',
+    'branch_map': [
+      (r'trunk/src/native_client', r'refs/heads/master'),
+    ],
+  },
+}
+
+# Key for the 'git-svn' ID metadata commit footer entry.
+GIT_SVN_ID_FOOTER_KEY = 'git-svn-id'
+# e.g., git-svn-id: https://v8.googlecode.com/svn/trunk@23117
+#     ce2b1a6d-e550-0410-aec6-3dcde31c8c00
+GIT_SVN_ID_RE = re.compile(r'((?:\w+)://[^@]+)@(\d+)\s+(?:[a-zA-Z0-9\-]+)')
+
+
+# This is the git mirror of the buildspecs repository. We could rely on the svn
+# checkout, now that the git buildspecs are checked in alongside the svn
+# buildspecs, but we're going to want to pull all the buildspecs from here
+# eventually anyhow, and there's already some logic to pull from git (for the
+# old git_buildspecs.git repo), so just stick with that.
+GIT_BUILDSPEC_REPO = (
+    'https://chrome-internal.googlesource.com/chrome/tools/buildspec')
+
+# Copied from scripts/recipes/chromium.py.
+GOT_REVISION_MAPPINGS = {
+    '/chrome/trunk/src': {
+        'src/': 'got_revision',
+        'src/native_client/': 'got_nacl_revision',
+        'src/tools/swarm_client/': 'got_swarm_client_revision',
+        'src/tools/swarming_client/': 'got_swarming_client_revision',
+        'src/third_party/WebKit/': 'got_webkit_revision',
+        'src/third_party/webrtc/': 'got_webrtc_revision',
+        'src/v8/': 'got_v8_revision',
+    }
+}
+
+
+BOT_UPDATE_MESSAGE = """
+What is the "Bot Update" step?
+==============================
+
+This step ensures that the source checkout on the bot (e.g. Chromium's src/ and
+its dependencies) is checked out in a consistent state. This means that all of
+the necessary repositories are checked out, no extra repositories are checked
+out, and no locally modified files are present.
+
+These actions used to be taken care of by the "gclient revert" and "update"
+steps. However, those steps are known to be buggy and occasionally flaky. This
+step has two main advantages over them:
+  * it only operates in Git, so the logic can be clearer and cleaner; and
+  * it is a slave-side script, so its behavior can be modified without
+    restarting the master.
+
+Why Git, you ask? Because that is the direction that the Chromium project is
+heading. This step is an integral part of the transition from using the SVN repo
+at chrome/trunk/src to using the Git repo src.git. Please pardon the dust while
+we fully convert everything to Git. This message will get out of your way
+eventually, and the waterfall will be a happier place because of it.
+
+This step can be activated or deactivated independently on every builder on
+every master. When it is active, the "gclient revert" and "update" steps become
+no-ops. When it is inactive, it prints this message, cleans up after itself, and
+lets everything else continue as though nothing has changed. Eventually, when
+everything is stable enough, this step will replace them entirely.
+
+Debugging information:
+(master/builder/slave may be unspecified on recipes)
+master: %(master)s
+builder: %(builder)s
+slave: %(slave)s
+forced by recipes: %(recipe)s
+CURRENT_DIR: %(CURRENT_DIR)s
+BUILDER_DIR: %(BUILDER_DIR)s
+SLAVE_DIR: %(SLAVE_DIR)s
+THIS_DIR: %(THIS_DIR)s
+SCRIPTS_DIR: %(SCRIPTS_DIR)s
+BUILD_DIR: %(BUILD_DIR)s
+ROOT_DIR: %(ROOT_DIR)s
+DEPOT_TOOLS_DIR: %(DEPOT_TOOLS_DIR)s
+bot_update.py is:"""
+
+ACTIVATED_MESSAGE = """ACTIVE.
+The bot will perform a Git checkout in this step.
+The "gclient revert" and "update" steps are no-ops.
+
+"""
+
+NOT_ACTIVATED_MESSAGE = """INACTIVE.
+This step does nothing. You actually want to look at the "update" step.
+
+"""
+
+
+GCLIENT_TEMPLATE = """solutions = %(solutions)s
+
+cache_dir = r%(cache_dir)s
+%(target_os)s
+%(target_os_only)s
+"""
+
+
+internal_data = {}
+if BUILD_INTERNAL_DIR:
+  local_vars = {}
+  try:
+    execfile(os.path.join(
+        BUILD_INTERNAL_DIR, 'scripts', 'slave', 'bot_update_cfg.py'),
+        local_vars)
+  except Exception:
+    # Same as if BUILD_INTERNAL_DIR didn't exist in the first place.
+    print 'Warning: unable to read internal configuration file.'
+    print 'If this is an internal bot, this step may be erroneously inactive.'
+  internal_data = local_vars
+
+RECOGNIZED_PATHS = {
+    # If SVN path matches key, the entire URL is rewritten to the Git url.
+    '/chrome/trunk/src':
+        CHROMIUM_SRC_URL,
+    '/chrome/trunk/src/tools/cros.DEPS':
+        CHROMIUM_GIT_HOST + '/chromium/src/tools/cros.DEPS.git',
+}
+RECOGNIZED_PATHS.update(internal_data.get('RECOGNIZED_PATHS', {}))
+
+ENABLED_MASTERS = [
+    'bot_update.always_on',
+    'chromium.android',
+    'chromium.angle',
+    'chromium.chrome',
+    'chromium.chromedriver',
+    'chromium.chromiumos',
+    'chromium',
+    'chromium.fyi',
+    'chromium.goma',
+    'chromium.gpu',
+    'chromium.gpu.fyi',
+    'chromium.infra',
+    'chromium.infra.cron',
+    'chromium.linux',
+    'chromium.lkgr',
+    'chromium.mac',
+    'chromium.memory',
+    'chromium.memory.fyi',
+    'chromium.perf',
+    'chromium.perf.fyi',
+    'chromium.swarm',
+    'chromium.webkit',
+    'chromium.webrtc',
+    'chromium.webrtc.fyi',
+    'chromium.win',
+    'client.catapult',
+    'client.drmemory',
+    'client.mojo',
+    'client.nacl',
+    'client.nacl.ports',
+    'client.nacl.sdk',
+    'client.nacl.toolchain',
+    'client.pdfium',
+    'client.skia',
+    'client.skia.fyi',
+    'client.v8',
+    'client.v8.branches',
+    'client.v8.fyi',
+    'client.webrtc',
+    'client.webrtc.fyi',
+    'tryserver.blink',
+    'tryserver.client.catapult',
+    'tryserver.client.mojo',
+    'tryserver.chromium.android',
+    'tryserver.chromium.angle',
+    'tryserver.chromium.linux',
+    'tryserver.chromium.mac',
+    'tryserver.chromium.perf',
+    'tryserver.chromium.win',
+    'tryserver.infra',
+    'tryserver.nacl',
+    'tryserver.v8',
+    'tryserver.webrtc',
+]
+ENABLED_MASTERS += internal_data.get('ENABLED_MASTERS', [])
+
+ENABLED_BUILDERS = {
+    'client.dart.fyi': [
+        'v8-linux-release',
+        'v8-mac-release',
+        'v8-win-release',
+    ],
+    'client.dynamorio': [
+        'linux-v8-dr',
+    ],
+}
+ENABLED_BUILDERS.update(internal_data.get('ENABLED_BUILDERS', {}))
+
+ENABLED_SLAVES = {}
+ENABLED_SLAVES.update(internal_data.get('ENABLED_SLAVES', {}))
+
+# Disabled filters get run AFTER enabled filters, so for example if a builder
+# config is enabled, but a bot on that builder is disabled, that bot will
+# be disabled.
+DISABLED_BUILDERS = {}
+DISABLED_BUILDERS.update(internal_data.get('DISABLED_BUILDERS', {}))
+
+DISABLED_SLAVES = {}
+DISABLED_SLAVES.update(internal_data.get('DISABLED_SLAVES', {}))
+
+# These masters work only in Git, meaning for got_revision, always output
+# a git hash rather than a SVN rev.
+GIT_MASTERS = [
+    'client.v8',
+    'client.v8.branches',
+    'tryserver.v8',
+]
+GIT_MASTERS += internal_data.get('GIT_MASTERS', [])
+
+
+# How many times to try before giving up.
+ATTEMPTS = 5
+
+# Find deps2git
+DEPS2GIT_DIR_PATH = path.join(SCRIPTS_DIR, 'tools', 'deps2git')
+DEPS2GIT_PATH = path.join(DEPS2GIT_DIR_PATH, 'deps2git.py')
+S2G_INTERNAL_PATH = path.join(SCRIPTS_DIR, 'tools', 'deps2git_internal',
+                              'svn_to_git_internal.py')
+
+# ../../cache_dir aka /b/build/slave/cache_dir
+GIT_CACHE_PATH = path.join(DEPOT_TOOLS_DIR, 'git_cache.py')
+CACHE_DIR = path.join(SLAVE_DIR, 'cache_dir')
+# Because we print CACHE_DIR out into a .gclient file, and then later run
+# eval() on it, backslashes need to be escaped, otherwise "E:\b\build" gets
+# parsed as "E:[\x08][\x08]uild".
+if sys.platform.startswith('win'):
+  CACHE_DIR = CACHE_DIR.replace('\\', '\\\\')
+
+# Find the patch tool.
+if sys.platform.startswith('win'):
+  if not BUILD_INTERNAL_DIR:
+    print 'Warning: could not find patch tool because there is no '
+    print 'build_internal present.'
+    PATCH_TOOL = None
+  else:
+    PATCH_TOOL = path.join(BUILD_INTERNAL_DIR, 'tools', 'patch.EXE')
+else:
+  PATCH_TOOL = '/usr/bin/patch'
+
+# If there is less than 100GB of disk space on the system, then we do
+# a shallow checkout.
+SHALLOW_CLONE_THRESHOLD = 100 * 1024 * 1024 * 1024
+
+
+class SubprocessFailed(Exception):
+  def __init__(self, message, code, output):
+    Exception.__init__(self, message)
+    self.code = code
+    self.output = output
+
+
+class PatchFailed(SubprocessFailed):
+  pass
+
+
+class GclientSyncFailed(SubprocessFailed):
+  pass
+
+
+class SVNRevisionNotFound(Exception):
+  pass
+
+
+class InvalidDiff(Exception):
+  pass
+
+
+class Inactive(Exception):
+  """Not really an exception, just used to exit early cleanly."""
+  pass
+
+
+RETRY = object()
+OK = object()
+FAIL = object()
+
+
+class PsPrinter(object):
+  def __init__(self, interval=300):
+    self.interval = interval
+    self.active = sys.platform.startswith('linux2')
+    self.thread = None
+
+  @staticmethod
+  def print_pstree():
+    """Debugging function used to print "ps auxwwf" for stuck processes."""
+    subprocess.call(['ps', 'auxwwf'])
+
+  def poke(self):
+    if self.active:
+      self.cancel()
+      self.thread = threading.Timer(self.interval, self.print_pstree)
+      self.thread.start()
+
+  def cancel(self):
+    if self.active and self.thread is not None:
+      self.thread.cancel()
+      self.thread = None
+
+
+def call(*args, **kwargs):  # pragma: no cover
+  """Interactive subprocess call."""
+  kwargs['stdout'] = subprocess.PIPE
+  kwargs['stderr'] = subprocess.STDOUT
+  kwargs.setdefault('bufsize', BUF_SIZE)
+  cwd = kwargs.get('cwd', os.getcwd())
+  result_fn = kwargs.pop('result_fn', lambda code, out: RETRY if code else OK)
+  stdin_data = kwargs.pop('stdin_data', None)
+  tries = kwargs.pop('tries', ATTEMPTS)
+  if stdin_data:
+    kwargs['stdin'] = subprocess.PIPE
+  out = cStringIO.StringIO()
+  new_env = kwargs.get('env', {})
+  env = copy.copy(os.environ)
+  env.update(new_env)
+  kwargs['env'] = env
+  attempt = 0
+  for attempt in range(1, tries + 1):
+    attempt_msg = ' (attempt #%d)' % attempt if attempt else ''
+    if new_env:
+      print '===Injecting Environment Variables==='
+      for k, v in sorted(new_env.items()):
+        print '%s: %s' % (k, v)
+    print '===Running %s%s===' % (' '.join(args), attempt_msg)
+    print 'In directory: %s' % cwd
+    start_time = time.time()
+    proc = subprocess.Popen(args, **kwargs)
+    if stdin_data:
+      proc.stdin.write(stdin_data)
+      proc.stdin.close()
+    psprinter = PsPrinter()
+    # This is here because passing 'sys.stdout' into stdout for proc will
+    # produce out of order output.
+    hanging_cr = False
+    while True:
+      psprinter.poke()
+      buf = proc.stdout.read(BUF_SIZE)
+      if not buf:
+        break
+      if hanging_cr:
+        buf = '\r' + buf
+      hanging_cr = buf.endswith('\r')
+      if hanging_cr:
+        buf = buf[:-1]
+      buf = buf.replace('\r\n', '\n').replace('\r', '\n')
+      sys.stdout.write(buf)
+      out.write(buf)
+    if hanging_cr:
+      sys.stdout.write('\n')
+      out.write('\n')
+    psprinter.cancel()
+
+    code = proc.wait()
+    elapsed_time = ((time.time() - start_time) / 60.0)
+    outval = out.getvalue()
+    result = result_fn(code, outval)
+    if result in (FAIL, RETRY):
+      print '===Failed in %.1f mins===' % elapsed_time
+      print
+    else:
+      print '===Succeeded in %.1f mins===' % elapsed_time
+      print
+      return outval
+    if result is FAIL:
+      break
+    if result is RETRY and attempt < tries:
+      sleep_backoff = 4 ** attempt
+      sleep_time = random.randint(sleep_backoff, int(sleep_backoff * 1.2))
+      print '===backing off, sleeping for %d secs===' % sleep_time
+      time.sleep(sleep_time)
+
+  raise SubprocessFailed('%s failed with code %d in %s after %d attempts.' %
+                         (' '.join(args), code, cwd, attempt),
+                         code, outval)
+
+
+def git(*args, **kwargs):  # pragma: no cover
+  """Wrapper around call specifically for Git commands."""
+  if args and args[0] == 'cache':
+    # Rewrite "git cache" calls into "python git_cache.py".
+    cmd = (sys.executable, '-u', GIT_CACHE_PATH) + args[1:]
+  else:
+    git_executable = 'git'
+    # On windows, subprocess doesn't fuzzy-match 'git' to 'git.bat', so we
+    # have to do it explicitly. This is better than passing shell=True.
+    if sys.platform.startswith('win'):
+      git_executable += '.bat'
+    cmd = (git_executable,) + args
+  return call(*cmd, **kwargs)
+
+
+def get_gclient_spec(solutions, target_os, target_os_only):
+  return GCLIENT_TEMPLATE % {
+      'solutions': pprint.pformat(solutions, indent=4),
+      'cache_dir': '"%s"' % CACHE_DIR,
+      'target_os': ('\ntarget_os=%s' % target_os) if target_os else '',
+      'target_os_only': '\ntarget_os_only=%s' % target_os_only
+  }
+
+
+def check_enabled(master, builder, slave):
+  if master in ENABLED_MASTERS:
+    return True
+  builder_list = ENABLED_BUILDERS.get(master)
+  if builder_list and builder in builder_list:
+    return True
+  slave_list = ENABLED_SLAVES.get(master)
+  if slave_list and slave in slave_list:
+    return True
+  return False
+
+
+def check_disabled(master, builder, slave):
+  """Returns True if disabled, False if not disabled."""
+  builder_list = DISABLED_BUILDERS.get(master)
+  if builder_list and builder in builder_list:
+    return True
+  slave_list = DISABLED_SLAVES.get(master)
+  if slave_list and slave in slave_list:
+    return True
+  return False
+
+
+def check_valid_host(master, builder, slave):
+  return (check_enabled(master, builder, slave)
+          and not check_disabled(master, builder, slave))
+
+
+def maybe_ignore_revision(revision, buildspec):
+  """Handle builders that don't care what buildbot tells them to build.
+
+  This is especially the case with branch builders that build from buildspecs
+  and/or trigger off multiple repositories, where the --revision passed in has
+  nothing to do with the solution being built. Clearing the revision in this
+  case causes bot_update to use HEAD rather that trying to checkout an
+  inappropriate version of the solution.
+  """
+  if buildspec and buildspec.container == 'branches':
+    return []
+  return revision
+
+
+def solutions_printer(solutions):
+  """Prints gclient solution to stdout."""
+  print 'Gclient Solutions'
+  print '================='
+  for solution in solutions:
+    name = solution.get('name')
+    url = solution.get('url')
+    print '%s (%s)' % (name, url)
+    if solution.get('deps_file'):
+      print '  Dependencies file is %s' % solution['deps_file']
+    if 'managed' in solution:
+      print '  Managed mode is %s' % ('ON' if solution['managed'] else 'OFF')
+    custom_vars = solution.get('custom_vars')
+    if custom_vars:
+      print '  Custom Variables:'
+      for var_name, var_value in sorted(custom_vars.iteritems()):
+        print '    %s = %s' % (var_name, var_value)
+    custom_deps = solution.get('custom_deps')
+    if 'custom_deps' in solution:
+      print '  Custom Dependencies:'
+      for deps_name, deps_value in sorted(custom_deps.iteritems()):
+        if deps_value:
+          print '    %s -> %s' % (deps_name, deps_value)
+        else:
+          print '    %s: Ignore' % deps_name
+    for k, v in solution.iteritems():
+      # Print out all the keys we don't know about.
+      if k in ['name', 'url', 'deps_file', 'custom_vars', 'custom_deps',
+               'managed']:
+        continue
+      print '  %s is %s' % (k, v)
+    print
+
+
+def solutions_to_git(input_solutions):
+  """Modifies urls in solutions to point at Git repos.
+
+  returns: (git solution, svn root of first solution) tuple.
+  """
+  assert input_solutions
+  solutions = copy.deepcopy(input_solutions)
+  first_solution = True
+  buildspec = None
+  for solution in solutions:
+    original_url = solution['url']
+    parsed_url = urlparse.urlparse(original_url)
+    parsed_path = parsed_url.path
+
+    # Rewrite SVN urls into Git urls.
+    buildspec_m = re.match(BUILDSPEC_RE, parsed_path)
+    if first_solution and buildspec_m:
+      solution['url'] = GIT_BUILDSPEC_PATH
+      buildspec = BUILDSPEC_TYPE(
+          container=buildspec_m.group(1),
+          version=buildspec_m.group(2),
+      )
+      solution['deps_file'] = path.join(buildspec.container, buildspec.version,
+                                        'DEPS')
+    elif parsed_path in RECOGNIZED_PATHS:
+      solution['url'] = RECOGNIZED_PATHS[parsed_path]
+      solution['deps_file'] = '.DEPS.git'
+    elif parsed_url.scheme == 'https' and 'googlesource' in parsed_url.netloc:
+      pass
+    else:
+      print 'Warning: %s' % ('path %r not recognized' % parsed_path,)
+
+    # Strip out deps containing $$V8_REV$$, etc.
+    if 'custom_deps' in solution:
+      new_custom_deps = {}
+      for deps_name, deps_value in solution['custom_deps'].iteritems():
+        if deps_value and '$$' in deps_value:
+          print 'Dropping %s:%s from custom deps' % (deps_name, deps_value)
+        else:
+          new_custom_deps[deps_name] = deps_value
+      solution['custom_deps'] = new_custom_deps
+
+    if first_solution:
+      root = parsed_path
+      first_solution = False
+
+    solution['managed'] = False
+    # We don't want gclient to be using a safesync URL. Instead it should
+    # using the lkgr/lkcr branch/tags.
+    if 'safesync_url' in solution:
+      print 'Removing safesync url %s from %s' % (solution['safesync_url'],
+                                                  parsed_path)
+      del solution['safesync_url']
+  return solutions, root, buildspec
+
+
+def remove(target):
+  """Remove a target by moving it into build.dead."""
+  dead_folder = path.join(BUILDER_DIR, 'build.dead')
+  if not path.exists(dead_folder):
+    os.makedirs(dead_folder)
+  os.rename(target, path.join(dead_folder, uuid.uuid4().hex))
+
+
+def ensure_no_checkout(dir_names, scm_dirname):
+  """Ensure that there is no undesired checkout under build/.
+
+  If there is an incorrect checkout under build/, then
+  move build/ to build.dead/
+  This function will check each directory in dir_names.
+
+  scm_dirname is expected to be either ['.svn', '.git']
+  """
+  assert scm_dirname in ['.svn', '.git', '*']
+  has_checkout = any(path.exists(path.join(os.getcwd(), dir_name, scm_dirname))
+                     for dir_name in dir_names)
+
+  if has_checkout or scm_dirname == '*':
+    build_dir = os.getcwd()
+    prefix = ''
+    if scm_dirname != '*':
+      prefix = '%s detected in checkout, ' % scm_dirname
+
+    for filename in os.listdir(build_dir):
+      deletion_target = path.join(build_dir, filename)
+      print '%sdeleting %s...' % (prefix, deletion_target),
+      remove(deletion_target)
+      print 'done'
+
+
+def gclient_configure(solutions, target_os, target_os_only):
+  """Should do the same thing as gclient --spec='...'."""
+  with codecs.open('.gclient', mode='w', encoding='utf-8') as f:
+    f.write(get_gclient_spec(solutions, target_os, target_os_only))
+
+
+def gclient_sync(with_branch_heads, shallow):
+  # We just need to allocate a filename.
+  fd, gclient_output_file = tempfile.mkstemp(suffix='.json')
+  os.close(fd)
+  gclient_bin = 'gclient.bat' if sys.platform.startswith('win') else 'gclient'
+  cmd = [gclient_bin, 'sync', '--verbose', '--reset', '--force',
+         '--ignore_locks', '--output-json', gclient_output_file,
+         '--nohooks', '--noprehooks', '--delete_unversioned_trees']
+  if with_branch_heads:
+    cmd += ['--with_branch_heads']
+  if shallow:
+    cmd += ['--shallow']
+
+  try:
+    call(*cmd, tries=1)
+  except SubprocessFailed as e:
+    # Throw a GclientSyncFailed exception so we can catch this independently.
+    raise GclientSyncFailed(e.message, e.code, e.output)
+  else:
+    with open(gclient_output_file) as f:
+      return json.load(f)
+  finally:
+    os.remove(gclient_output_file)
+
+
+def gclient_runhooks(gyp_envs):
+  gclient_bin = 'gclient.bat' if sys.platform.startswith('win') else 'gclient'
+  env = dict([env_var.split('=', 1) for env_var in gyp_envs])
+  call(gclient_bin, 'runhooks', env=env)
+
+
+def gclient_revinfo():
+  gclient_bin = 'gclient.bat' if sys.platform.startswith('win') else 'gclient'
+  return call(gclient_bin, 'revinfo', '-a') or ''
+
+
+def create_manifest():
+  manifest = {}
+  output = gclient_revinfo()
+  for line in output.strip().splitlines():
+    match = REVINFO_RE.match(line.strip())
+    if match:
+      manifest[match.group(1)] = {
+        'repository': match.group(2),
+        'revision': match.group(3),
+      }
+    else:
+      print "WARNING: Couldn't match revinfo line:\n%s" % line
+  return manifest
+
+
+def get_commit_message_footer_map(message):
+  """Returns: (dict) A dictionary of commit message footer entries.
+  """
+  footers = {}
+
+  # Extract the lines in the footer block.
+  lines = []
+  for line in message.strip().splitlines():
+    line = line.strip()
+    if len(line) == 0:
+      del lines[:]
+      continue
+    lines.append(line)
+
+  # Parse the footer
+  for line in lines:
+    m = COMMIT_FOOTER_ENTRY_RE.match(line)
+    if not m:
+      # If any single line isn't valid, the entire footer is invalid.
+      footers.clear()
+      return footers
+    footers[m.group(1)] = m.group(2).strip()
+  return footers
+
+
+def get_commit_message_footer(message, key):
+  """Returns: (str/None) The footer value for 'key', or None if none was found.
+  """
+  return get_commit_message_footer_map(message).get(key)
+
+
+def get_svn_rev(git_hash, dir_name):
+  log = git('log', '-1', git_hash, cwd=dir_name)
+  git_svn_id = get_commit_message_footer(log, GIT_SVN_ID_FOOTER_KEY)
+  if not git_svn_id:
+    return None
+  m = GIT_SVN_ID_RE.match(git_svn_id)
+  if not m:
+    return None
+  return int(m.group(2))
+
+
+def get_git_hash(revision, branch, sln_dir):
+  """We want to search for the SVN revision on the git-svn branch.
+
+  Note that git will search backwards from origin/master.
+  """
+  match = "^%s: [^ ]*@%s " % (GIT_SVN_ID_FOOTER_KEY, revision)
+  ref = branch if branch.startswith('refs/') else 'origin/%s' % branch
+  cmd = ['log', '-E', '--grep', match, '--format=%H', '--max-count=1', ref]
+  result = git(*cmd, cwd=sln_dir).strip()
+  if result:
+    return result
+  raise SVNRevisionNotFound('We can\'t resolve svn r%s into a git hash in %s' %
+                            (revision, sln_dir))
+
+
+def _last_commit_for_file(filename, repo_base):
+  cmd = ['log', '--format=%H', '--max-count=1', '--', filename]
+  return git(*cmd, cwd=repo_base).strip()
+
+
+def need_to_run_deps2git(repo_base, deps_file, deps_git_file):
+  """Checks to see if we need to run deps2git.
+
+  Returns True if there was a DEPS change after the last .DEPS.git update
+  or if DEPS has local modifications.
+  """
+  # See if DEPS is dirty
+  deps_file_status = git(
+      'status', '--porcelain', deps_file, cwd=repo_base).strip()
+  if deps_file_status and deps_file_status.startswith('M '):
+    return True
+
+  last_known_deps_ref = _last_commit_for_file(deps_file, repo_base)
+  last_known_deps_git_ref = _last_commit_for_file(deps_git_file, repo_base)
+  merge_base_ref = git('merge-base', last_known_deps_ref,
+                       last_known_deps_git_ref, cwd=repo_base).strip()
+
+  # If the merge base of the last DEPS and last .DEPS.git file is not
+  # equivilent to the hash of the last DEPS file, that means the DEPS file
+  # was committed after the last .DEPS.git file.
+  return last_known_deps_ref != merge_base_ref
+
+
+def ensure_deps2git(solution, shallow):
+  repo_base = path.join(os.getcwd(), solution['name'])
+  deps_file = path.join(repo_base, 'DEPS')
+  deps_git_file = path.join(repo_base, '.DEPS.git')
+  if (not git('ls-files', 'DEPS', cwd=repo_base).strip() or
+      not git('ls-files', '.DEPS.git', cwd=repo_base).strip()):
+    return
+
+  print 'Checking if %s is newer than %s' % (deps_file, deps_git_file)
+  if not need_to_run_deps2git(repo_base, deps_file, deps_git_file):
+    return
+
+  print '===DEPS file modified, need to run deps2git==='
+  cmd = [sys.executable, DEPS2GIT_PATH,
+         '--workspace', os.getcwd(),
+         '--cache_dir', CACHE_DIR,
+         '--deps', deps_file,
+         '--out', deps_git_file]
+  if 'chrome-internal.googlesource' in solution['url']:
+    cmd.extend(['--extra-rules', S2G_INTERNAL_PATH])
+  if shallow:
+    cmd.append('--shallow')
+  call(*cmd)
+
+
+def emit_log_lines(name, lines):
+  for line in lines.splitlines():
+    print '@@@STEP_LOG_LINE@%s@%s@@@' % (name, line)
+  print '@@@STEP_LOG_END@%s@@@' % name
+
+
+def emit_properties(properties):
+  for property_name, property_value in sorted(properties.items()):
+    print '@@@SET_BUILD_PROPERTY@%s@"%s"@@@' % (property_name, property_value)
+
+
+# Derived from:
+# http://code.activestate.com/recipes/577972-disk-usage/?in=user-4178764
+def get_total_disk_space():
+  cwd = os.getcwd()
+  # Windows is the only platform that doesn't support os.statvfs, so
+  # we need to special case this.
+  if sys.platform.startswith('win'):
+    _, total, free = (ctypes.c_ulonglong(), ctypes.c_ulonglong(), \
+                      ctypes.c_ulonglong())
+    if sys.version_info >= (3,) or isinstance(cwd, unicode):
+      fn = ctypes.windll.kernel32.GetDiskFreeSpaceExW
+    else:
+      fn = ctypes.windll.kernel32.GetDiskFreeSpaceExA
+    ret = fn(cwd, ctypes.byref(_), ctypes.byref(total), ctypes.byref(free))
+    if ret == 0:
+      # WinError() will fetch the last error code.
+      raise ctypes.WinError()
+    return (total.value, free.value)
+
+  else:
+    st = os.statvfs(cwd)
+    free = st.f_bavail * st.f_frsize
+    total = st.f_blocks * st.f_frsize
+    return (total, free)
+
+
+def get_target_revision(folder_name, git_url, revisions):
+  normalized_name = folder_name.strip('/')
+  if normalized_name in revisions:
+    return revisions[normalized_name]
+  if git_url in revisions:
+    return revisions[git_url]
+  return None
+
+
+def force_revision(folder_name, revision):
+  split_revision = revision.split(':', 1)
+  branch = 'master'
+  if len(split_revision) == 2:
+    # Support for "branch:revision" syntax.
+    branch, revision = split_revision
+
+  if revision and revision.upper() != 'HEAD':
+    if revision and revision.isdigit() and len(revision) < 40:
+      # rev_num is really a svn revision number, convert it into a git hash.
+      git_ref = get_git_hash(int(revision), branch, folder_name)
+    else:
+      # rev_num is actually a git hash or ref, we can just use it.
+      git_ref = revision
+    git('checkout', '--force', git_ref, cwd=folder_name)
+  else:
+    ref = branch if branch.startswith('refs/') else 'origin/%s' % branch
+    git('checkout', '--force', ref, cwd=folder_name)
+
+def git_checkout(solutions, revisions, shallow, refs):
+  build_dir = os.getcwd()
+  # Before we do anything, break all git_cache locks.
+  if path.isdir(CACHE_DIR):
+    git('cache', 'unlock', '-vv', '--force', '--all', '--cache-dir', CACHE_DIR)
+    for item in os.listdir(CACHE_DIR):
+      filename = os.path.join(CACHE_DIR, item)
+      if item.endswith('.lock'):
+        raise Exception('%s exists after cache unlock' % filename)
+  first_solution = True
+  for sln in solutions:
+    # This is so we can loop back and try again if we need to wait for the
+    # git mirrors to update from SVN.
+    done = False
+    tries_left = 60
+    while not done:
+      name = sln['name']
+      url = sln['url']
+      if url == CHROMIUM_SRC_URL or url + '.git' == CHROMIUM_SRC_URL:
+        # Experiments show there's little to be gained from
+        # a shallow clone of src.
+        shallow = False
+      sln_dir = path.join(build_dir, name)
+      s = ['--shallow'] if shallow else []
+      populate_cmd = (['cache', 'populate', '--ignore_locks', '-v',
+                       '--cache-dir', CACHE_DIR] + s + [url])
+      for ref in refs:
+        populate_cmd.extend(['--ref', ref])
+      git(*populate_cmd)
+      mirror_dir = git(
+          'cache', 'exists', '--quiet', '--cache-dir', CACHE_DIR, url).strip()
+      clone_cmd = (
+          'clone', '--no-checkout', '--local', '--shared', mirror_dir, sln_dir)
+
+      try:
+        if not path.isdir(sln_dir):
+          git(*clone_cmd)
+        else:
+          git('remote', 'set-url', 'origin', mirror_dir, cwd=sln_dir)
+          git('fetch', 'origin', cwd=sln_dir)
+        for ref in refs:
+          refspec = '%s:%s' % (ref, ref.lstrip('+'))
+          git('fetch', 'origin', refspec, cwd=sln_dir)
+
+        revision = get_target_revision(name, url, revisions) or 'HEAD'
+        force_revision(sln_dir, revision)
+        done = True
+      except SubprocessFailed as e:
+        # Exited abnormally, theres probably something wrong.
+        # Lets wipe the checkout and try again.
+        tries_left -= 1
+        if tries_left > 0:
+          print 'Something failed: %s.' % str(e)
+          print 'waiting 5 seconds and trying again...'
+          time.sleep(5)
+        else:
+          raise
+        remove(sln_dir)
+      except SVNRevisionNotFound:
+        tries_left -= 1
+        if tries_left > 0:
+          # If we don't have the correct revision, wait and try again.
+          print 'We can\'t find revision %s.' % revision
+          print 'The svn to git replicator is probably falling behind.'
+          print 'waiting 5 seconds and trying again...'
+          time.sleep(5)
+        else:
+          raise
+
+    git('clean', '-dff', cwd=sln_dir)
+
+    if first_solution:
+      git_ref = git('log', '--format=%H', '--max-count=1',
+                    cwd=sln_dir).strip()
+    first_solution = False
+  return git_ref
+
+
+def _download(url):
+  """Fetch url and return content, with retries for flake."""
+  for attempt in xrange(ATTEMPTS):
+    try:
+      return urllib2.urlopen(url).read()
+    except Exception:
+      if attempt == ATTEMPTS - 1:
+        raise
+
+
+def parse_diff(diff):
+  """Takes a unified diff and returns a list of diffed files and their diffs.
+
+  The return format is a list of pairs of:
+    (<filename>, <diff contents>)
+  <diff contents> is inclusive of the diff line.
+  """
+  result = []
+  current_diff = ''
+  current_header = None
+  for line in diff.splitlines():
+    # "diff" is for git style patches, and "Index: " is for SVN style patches.
+    if line.startswith('diff') or line.startswith('Index: '):
+      if current_header:
+        # If we are in a diff portion, then save the diff.
+        result.append((current_header, '%s\n' % current_diff))
+      git_header_match = re.match(r'diff (?:--git )?(\S+) (\S+)', line)
+      svn_header_match = re.match(r'Index: (.*)', line)
+
+      if git_header_match:
+        # First, see if its a git style header.
+        from_file = git_header_match.group(1)
+        to_file = git_header_match.group(2)
+        if from_file != to_file and from_file.startswith('a/'):
+          # Sometimes git prepends 'a/' and 'b/' in front of file paths.
+          from_file = from_file[2:]
+        current_header = from_file
+
+      elif svn_header_match:
+        # Otherwise, check if its an SVN style header.
+        current_header = svn_header_match.group(1)
+
+      else:
+        # Otherwise... I'm not really sure what to do with this.
+        raise InvalidDiff('Can\'t process header: %s\nFull diff:\n%s' %
+                          (line, diff))
+
+      current_diff = ''
+    current_diff += '%s\n' % line
+  if current_header:
+    # We hit EOF, gotta save the last diff.
+    result.append((current_header, current_diff))
+  return result
+
+
+def get_svn_patch(patch_url):
+  """Fetch patch from patch_url, return list of (filename, diff)"""
+  svn_exe = 'svn.bat' if sys.platform.startswith('win') else 'svn'
+  patch_data = call(svn_exe, 'cat', patch_url)
+  return parse_diff(patch_data)
+
+
+def apply_svn_patch(patch_root, patches, whitelist=None, blacklist=None):
+  """Expects a list of (filename, diff), applies it on top of patch_root."""
+  if whitelist:
+    patches = [(name, diff) for name, diff in patches if name in whitelist]
+  elif blacklist:
+    patches = [(name, diff) for name, diff in patches if name not in blacklist]
+  diffs = [diff for _, diff in patches]
+  patch = ''.join(diffs)
+
+  if patch:
+    print '===Patching files==='
+    for filename, _ in patches:
+      print 'Patching %s' % filename
+    try:
+      call(PATCH_TOOL, '-p0', '--remove-empty-files', '--force', '--forward',
+          stdin_data=patch, cwd=patch_root, tries=1)
+      for filename, _ in patches:
+        full_filename = path.abspath(path.join(patch_root, filename))
+        git('add', full_filename, cwd=path.dirname(full_filename))
+    except SubprocessFailed as e:
+      raise PatchFailed(e.message, e.code, e.output)
+
+def apply_rietveld_issue(issue, patchset, root, server, _rev_map, _revision,
+                         email_file, key_file, whitelist=None, blacklist=None):
+  apply_issue_bin = ('apply_issue.bat' if sys.platform.startswith('win')
+                     else 'apply_issue')
+  cmd = [apply_issue_bin,
+         # The patch will be applied on top of this directory.
+         '--root_dir', root,
+         # Tell apply_issue how to fetch the patch.
+         '--issue', issue,
+         '--server', server,
+         # Always run apply_issue.py, otherwise it would see update.flag
+         # and then bail out.
+         '--force',
+         # Don't run gclient sync when it sees a DEPS change.
+         '--ignore_deps',
+         # TODO(tandrii): remove after http://crbug.com/537417 is resolved.
+         # Temporary enable verbosity to see if Rietveld requests are actually
+         # retried.
+         '-v', '-v',  # = logging.DEBUG level.
+  ]
+  # Use an oauth key file if specified.
+  if email_file and key_file:
+    cmd.extend(['--email-file', email_file, '--private-key-file', key_file])
+  else:
+    cmd.append('--no-auth')
+
+  if patchset:
+    cmd.extend(['--patchset', patchset])
+  if whitelist:
+    for item in whitelist:
+      cmd.extend(['--whitelist', item])
+  elif blacklist:
+    for item in blacklist:
+      cmd.extend(['--blacklist', item])
+
+  # Only try once, since subsequent failures hide the real failure.
+  try:
+    call(*cmd, tries=1)
+  except SubprocessFailed as e:
+    raise PatchFailed(e.message, e.code, e.output)
+
+def apply_gerrit_ref(gerrit_repo, gerrit_ref, root):
+  gerrit_repo = gerrit_repo or 'origin'
+  assert gerrit_ref
+  try:
+    base_rev = git('rev-parse', 'HEAD', cwd=root).strip()
+    git('retry', 'fetch', gerrit_repo, gerrit_ref, cwd=root, tries=1)
+    git('checkout', 'FETCH_HEAD', cwd=root)
+    git('reset', '--soft', base_rev, cwd=root)
+  except SubprocessFailed as e:
+    raise PatchFailed(e.message, e.code, e.output)
+
+def check_flag(flag_file):
+  """Returns True if the flag file is present."""
+  return os.path.isfile(flag_file)
+
+
+def delete_flag(flag_file):
+  """Remove bot update flag."""
+  if os.path.isfile(flag_file):
+    os.remove(flag_file)
+
+
+def emit_flag(flag_file):
+  """Deposit a bot update flag on the system to tell gclient not to run."""
+  print 'Emitting flag file at %s' % flag_file
+  with open(flag_file, 'wb') as f:
+    f.write('Success!')
+
+
+def get_commit_position_for_git_svn(url, revision):
+  """Generates a commit position string for a 'git-svn' URL/revision.
+
+  If the 'git-svn' URL maps to a known project, we will construct a commit
+  position branch value by applying substitution on the SVN URL.
+  """
+  # Identify the base URL so we can strip off trunk/branch name
+  project_config = branch = None
+  for _, project_config in GIT_SVN_PROJECT_MAP.iteritems():
+    if url.startswith(project_config['svn_url']):
+      branch = url[len(project_config['svn_url']):]
+      break
+
+  if branch:
+    # Strip any leading slashes
+    branch = branch.lstrip('/')
+
+    # Try and map the branch
+    for pattern, repl in project_config.get('branch_map', ()):
+      nbranch, subn = re.subn(pattern, repl, branch, count=1)
+      if subn:
+        print 'INFO: Mapped SVN branch to Git branch [%s] => [%s]' % (
+            branch, nbranch)
+        branch = nbranch
+        break
+  else:
+    # Use generic 'svn' branch
+    print 'INFO: Could not resolve project for SVN URL %r' % (url,)
+    branch = 'svn'
+  return '%s@{#%s}' % (branch, revision)
+
+
+def get_commit_position(git_path, revision='HEAD'):
+  """Dumps the 'git' log for a specific revision and parses out the commit
+  position.
+
+  If a commit position metadata key is found, its value will be returned.
+
+  Otherwise, we will search for a 'git-svn' metadata entry. If one is found,
+  we will compose a commit position from it, using its SVN revision value as
+  the revision.
+
+  If the 'git-svn' URL maps to a known project, we will construct a commit
+  position branch value by truncating the URL, mapping 'trunk' to
+  "refs/heads/master". Otherwise, we will return the generic branch, 'svn'.
+  """
+  git_log = git('log', '--format=%B', '-n1', revision, cwd=git_path)
+  footer_map = get_commit_message_footer_map(git_log)
+
+  # Search for commit position metadata
+  value = (footer_map.get(COMMIT_POSITION_FOOTER_KEY) or
+           footer_map.get(COMMIT_ORIGINAL_POSITION_FOOTER_KEY))
+  if value:
+    return value
+
+  # Compose a commit position from 'git-svn' metadata
+  value = footer_map.get(GIT_SVN_ID_FOOTER_KEY)
+  if value:
+    m = GIT_SVN_ID_RE.match(value)
+    if not m:
+      raise ValueError("Invalid 'git-svn' value: [%s]" % (value,))
+    return get_commit_position_for_git_svn(m.group(1), m.group(2))
+  return None
+
+
+def parse_got_revision(gclient_output, got_revision_mapping, use_svn_revs):
+  """Translate git gclient revision mapping to build properties.
+
+  If use_svn_revs is True, then translate git hashes in the revision mapping
+  to svn revision numbers.
+  """
+  properties = {}
+  solutions_output = {
+      # Make sure path always ends with a single slash.
+      '%s/' % path.rstrip('/') : solution_output for path, solution_output
+      in gclient_output['solutions'].iteritems()
+  }
+  for dir_name, property_name in got_revision_mapping.iteritems():
+    # Make sure dir_name always ends with a single slash.
+    dir_name = '%s/' % dir_name.rstrip('/')
+    if dir_name not in solutions_output:
+      continue
+    solution_output = solutions_output[dir_name]
+    if solution_output.get('scm') is None:
+      # This is an ignored DEPS, so the output got_revision should be 'None'.
+      git_revision = revision = commit_position = None
+    else:
+      # Since we are using .DEPS.git, everything had better be git.
+      assert solution_output.get('scm') == 'git'
+      git_revision = git('rev-parse', 'HEAD', cwd=dir_name).strip()
+      if use_svn_revs:
+        revision = get_svn_rev(git_revision, dir_name)
+        if not revision:
+          revision = git_revision
+      else:
+        revision = git_revision
+      commit_position = get_commit_position(dir_name)
+
+    properties[property_name] = revision
+    if revision != git_revision:
+      properties['%s_git' % property_name] = git_revision
+    if commit_position:
+      properties['%s_cp' % property_name] = commit_position
+
+  return properties
+
+
+def emit_json(out_file, did_run, gclient_output=None, **kwargs):
+  """Write run information into a JSON file."""
+  output = {}
+  output.update(gclient_output if gclient_output else {})
+  output.update({'did_run': did_run})
+  output.update(kwargs)
+  with open(out_file, 'wb') as f:
+    f.write(json.dumps(output, sort_keys=True))
+
+
+def ensure_deps_revisions(deps_url_mapping, solutions, revisions):
+  """Ensure correct DEPS revisions, ignores solutions."""
+  for deps_name, deps_data in sorted(deps_url_mapping.items()):
+    if deps_name.strip('/') in solutions:
+      # This has already been forced to the correct solution by git_checkout().
+      continue
+    revision = get_target_revision(deps_name, deps_data.get('url', None),
+                                   revisions)
+    if not revision:
+      continue
+    # TODO(hinoka): Catch SVNRevisionNotFound error maybe?
+    git('fetch', 'origin', cwd=deps_name)
+    force_revision(deps_name, revision)
+
+
+def ensure_checkout(solutions, revisions, first_sln, target_os, target_os_only,
+                    patch_root, issue, patchset, patch_url, rietveld_server,
+                    gerrit_repo, gerrit_ref, revision_mapping,
+                    apply_issue_email_file, apply_issue_key_file, buildspec,
+                    gyp_env, shallow, runhooks, refs):
+  # Get a checkout of each solution, without DEPS or hooks.
+  # Calling git directly because there is no way to run Gclient without
+  # invoking DEPS.
+  print 'Fetching Git checkout'
+
+  git_ref = git_checkout(solutions, revisions, shallow, refs)
+
+  patches = None
+  if patch_url:
+    patches = get_svn_patch(patch_url)
+
+  already_patched = []
+  patch_root = patch_root or ''
+  for solution in solutions:
+    if (patch_root == solution['name'] or
+        solution['name'].startswith(patch_root + '/')):
+      relative_root = solution['name'][len(patch_root) + 1:]
+      target = '/'.join([relative_root, 'DEPS']).lstrip('/')
+      if patches:
+        apply_svn_patch(patch_root, patches, whitelist=[target])
+        already_patched.append(target)
+      elif issue:
+        apply_rietveld_issue(issue, patchset, patch_root, rietveld_server,
+                             revision_mapping, git_ref, apply_issue_email_file,
+                             apply_issue_key_file, whitelist=[target])
+        already_patched.append(target)
+
+  if not buildspec:
+    # Run deps2git if there is a DEPS change after the last .DEPS.git commit.
+    for solution in solutions:
+      ensure_deps2git(solution, shallow)
+
+  # Ensure our build/ directory is set up with the correct .gclient file.
+  gclient_configure(solutions, target_os, target_os_only)
+
+  # Let gclient do the DEPS syncing.
+  # The branch-head refspec is a special case because its possible Chrome
+  # src, which contains the branch-head refspecs, is DEPSed in.
+  gclient_output = gclient_sync(buildspec or BRANCH_HEADS_REFSPEC in refs,
+                                shallow)
+
+  # Now that gclient_sync has finished, we should revert any .DEPS.git so that
+  # presubmit doesn't complain about it being modified.
+  if (not buildspec and
+      git('ls-files', '.DEPS.git', cwd=first_sln).strip()):
+    git('checkout', 'HEAD', '--', '.DEPS.git', cwd=first_sln)
+
+  if buildspec and runhooks:
+    # Run gclient runhooks if we're on an official builder.
+    # TODO(hinoka): Remove this when the official builders run their own
+    #               runhooks step.
+    gclient_runhooks(gyp_env)
+
+  # Finally, ensure that all DEPS are pinned to the correct revision.
+  dir_names = [sln['name'] for sln in solutions]
+  ensure_deps_revisions(gclient_output.get('solutions', {}),
+                        dir_names, revisions)
+  # Apply the rest of the patch here (sans DEPS)
+  if patches:
+    apply_svn_patch(patch_root, patches, blacklist=already_patched)
+  elif issue:
+    apply_rietveld_issue(issue, patchset, patch_root, rietveld_server,
+                         revision_mapping, git_ref, apply_issue_email_file,
+                         apply_issue_key_file, blacklist=already_patched)
+  elif gerrit_ref:
+    apply_gerrit_ref(gerrit_repo, gerrit_ref, patch_root)
+
+  # Reset the deps_file point in the solutions so that hooks get run properly.
+  for sln in solutions:
+    sln['deps_file'] = sln.get('deps_file', 'DEPS').replace('.DEPS.git', 'DEPS')
+  gclient_configure(solutions, target_os, target_os_only)
+
+  return gclient_output
+
+
+def parse_revisions(revisions, root):
+  """Turn a list of revision specs into a nice dictionary.
+
+  We will always return a dict with {root: something}.  By default if root
+  is unspecified, or if revisions is [], then revision will be assigned 'HEAD'
+  """
+  results = {root.strip('/'): 'HEAD'}
+  expanded_revisions = []
+  for revision in revisions:
+    # Allow rev1,rev2,rev3 format.
+    # TODO(hinoka): Delete this when webkit switches to recipes.
+    expanded_revisions.extend(revision.split(','))
+  for revision in expanded_revisions:
+    split_revision = revision.split('@')
+    if len(split_revision) == 1:
+      # This is just a plain revision, set it as the revision for root.
+      results[root] = split_revision[0]
+    elif len(split_revision) == 2:
+      # This is an alt_root@revision argument.
+      current_root, current_rev = split_revision
+
+      # We want to normalize svn/git urls into .git urls.
+      parsed_root = urlparse.urlparse(current_root)
+      if parsed_root.scheme == 'svn':
+        if parsed_root.path in RECOGNIZED_PATHS:
+          normalized_root = RECOGNIZED_PATHS[parsed_root.path]
+        else:
+          print 'WARNING: SVN path %s not recognized, ignoring' % current_root
+          continue
+      elif parsed_root.scheme in ['http', 'https']:
+        normalized_root = 'https://%s/%s' % (parsed_root.netloc,
+                                             parsed_root.path)
+        if not normalized_root.endswith('.git'):
+          normalized_root = '%s.git' % normalized_root
+      elif parsed_root.scheme:
+        print 'WARNING: Unrecognized scheme %s, ignoring' % parsed_root.scheme
+        continue
+      else:
+        # This is probably a local path.
+        normalized_root = current_root.strip('/')
+
+      results[normalized_root] = current_rev
+    else:
+      print ('WARNING: %r is not recognized as a valid revision specification,'
+             'skipping' % revision)
+  return results
+
+
+def parse_args():
+  parse = optparse.OptionParser()
+
+  parse.add_option('--issue', help='Issue number to patch from.')
+  parse.add_option('--patchset',
+                   help='Patchset from issue to patch from, if applicable.')
+  parse.add_option('--apply_issue_email_file',
+                   help='--email-file option passthrough for apply_patch.py.')
+  parse.add_option('--apply_issue_key_file',
+                   help='--private-key-file option passthrough for '
+                        'apply_patch.py.')
+  parse.add_option('--patch_url', help='Optional URL to SVN patch.')
+  parse.add_option('--root', dest='patch_root',
+                   help='DEPRECATED: Use --patch_root.')
+  parse.add_option('--patch_root', help='Directory to patch on top of.')
+  parse.add_option('--rietveld_server',
+                   default='codereview.chromium.org',
+                   help='Rietveld server.')
+  parse.add_option('--gerrit_repo',
+                   help='Gerrit repository to pull the ref from.')
+  parse.add_option('--gerrit_ref', help='Gerrit ref to apply.')
+  parse.add_option('--specs', help='Gcilent spec.')
+  parse.add_option('--master', help='Master name.')
+  parse.add_option('-f', '--force', action='store_true',
+                   help='Bypass check to see if we want to be run. '
+                        'Should ONLY be used locally or by smart recipes.')
+  parse.add_option('--revision_mapping',
+                   help='{"path/to/repo/": "property_name"}')
+  parse.add_option('--revision_mapping_file',
+                   help=('Same as revision_mapping, except its a path to a json'
+                         ' file containing that format.'))
+  parse.add_option('--revision', action='append', default=[],
+                   help='Revision to check out. Can be an SVN revision number, '
+                        'git hash, or any form of git ref.  Can prepend '
+                        'root@<rev> to specify which repository, where root '
+                        'is either a filesystem path, git https url, or '
+                        'svn url. To specify Tip of Tree, set rev to HEAD.'
+                        'To specify a git branch and an SVN rev, <rev> can be '
+                        'set to <branch>:<revision>.')
+  parse.add_option('--output_manifest', action='store_true',
+                   help=('Add manifest json to the json output.'))
+  parse.add_option('--slave_name', default=socket.getfqdn().split('.')[0],
+                   help='Hostname of the current machine, '
+                   'used for determining whether or not to activate.')
+  parse.add_option('--builder_name', help='Name of the builder, '
+                   'used for determining whether or not to activate.')
+  parse.add_option('--build_dir', default=os.getcwd())
+  parse.add_option('--flag_file', default=path.join(os.getcwd(),
+                                                    'update.flag'))
+  parse.add_option('--shallow', action='store_true',
+                   help='Use shallow clones for cache repositories.')
+  parse.add_option('--gyp_env', action='append', default=[],
+                   help='Environment variables to pass into gclient runhooks.')
+  parse.add_option('--clobber', action='store_true',
+                   help='Delete checkout first, always')
+  parse.add_option('--bot_update_clobber', action='store_true', dest='clobber',
+                   help='(synonym for --clobber)')
+  parse.add_option('-o', '--output_json',
+                   help='Output JSON information into a specified file')
+  parse.add_option('--no_shallow', action='store_true',
+                   help='Bypass disk detection and never shallow clone. '
+                        'Does not override the --shallow flag')
+  parse.add_option('--no_runhooks', action='store_true',
+                   help='Do not run hooks on official builder.')
+  parse.add_option('--refs', action='append',
+                   help='Also fetch this refspec for the main solution(s). '
+                        'Eg. +refs/branch-heads/*')
+  parse.add_option('--with_branch_heads', action='store_true',
+                    help='Always pass --with_branch_heads to gclient.  This '
+                          'does the same thing as --refs +refs/branch-heads/*')
+
+
+  options, args = parse.parse_args()
+
+  if not options.refs:
+    options.refs = []
+
+  if options.with_branch_heads:
+    options.refs.append(BRANCH_HEADS_REFSPEC)
+    del options.with_branch_heads
+
+  try:
+    if options.revision_mapping_file:
+      if options.revision_mapping:
+        print ('WARNING: Ignoring --revision_mapping: --revision_mapping_file '
+               'was set at the same time as --revision_mapping?')
+      with open(options.revision_mapping_file, 'r') as f:
+        options.revision_mapping = json.load(f)
+    elif options.revision_mapping:
+      options.revision_mapping = json.loads(options.revision_mapping)
+  except Exception as e:
+    print (
+        'WARNING: Caught execption while parsing revision_mapping*: %s'
+        % (str(e),)
+    )
+
+  return options, args
+
+
+def prepare(options, git_slns, active):
+  """Prepares the target folder before we checkout."""
+  dir_names = [sln.get('name') for sln in git_slns if 'name' in sln]
+  # If we're active now, but the flag file doesn't exist (we weren't active
+  # last run) or vice versa, blow away all checkouts.
+  if bool(active) != bool(check_flag(options.flag_file)):
+    ensure_no_checkout(dir_names, '*')
+  if options.output_json:
+    # Make sure we tell recipes that we didn't run if the script exits here.
+    emit_json(options.output_json, did_run=active)
+  if active:
+    if options.clobber:
+      ensure_no_checkout(dir_names, '*')
+    else:
+      ensure_no_checkout(dir_names, '.svn')
+    emit_flag(options.flag_file)
+  else:
+    delete_flag(options.flag_file)
+    raise Inactive  # This is caught in main() and we exit cleanly.
+
+  # Do a shallow checkout if the disk is less than 100GB.
+  total_disk_space, free_disk_space = get_total_disk_space()
+  total_disk_space_gb = int(total_disk_space / (1024 * 1024 * 1024))
+  used_disk_space_gb = int((total_disk_space - free_disk_space)
+                           / (1024 * 1024 * 1024))
+  percent_used = int(used_disk_space_gb * 100 / total_disk_space_gb)
+  step_text = '[%dGB/%dGB used (%d%%)]' % (used_disk_space_gb,
+                                           total_disk_space_gb,
+                                           percent_used)
+  if not options.output_json:
+    print '@@@STEP_TEXT@%s@@@' % step_text
+  if not options.shallow:
+    options.shallow = (total_disk_space < SHALLOW_CLONE_THRESHOLD
+                       and not options.no_shallow)
+
+  # The first solution is where the primary DEPS file resides.
+  first_sln = dir_names[0]
+
+  # Split all the revision specifications into a nice dict.
+  print 'Revisions: %s' % options.revision
+  revisions = parse_revisions(options.revision, first_sln)
+  print 'Fetching Git checkout at %s@%s' % (first_sln, revisions[first_sln])
+  return revisions, step_text
+
+
+def checkout(options, git_slns, specs, buildspec, master,
+             svn_root, revisions, step_text):
+  first_sln = git_slns[0]['name']
+  dir_names = [sln.get('name') for sln in git_slns if 'name' in sln]
+  try:
+    # Outer try is for catching patch failures and exiting gracefully.
+    # Inner try is for catching gclient failures and retrying gracefully.
+    try:
+      checkout_parameters = dict(
+          # First, pass in the base of what we want to check out.
+          solutions=git_slns,
+          revisions=revisions,
+          first_sln=first_sln,
+
+          # Also, target os variables for gclient.
+          target_os=specs.get('target_os', []),
+          target_os_only=specs.get('target_os_only', False),
+
+          # Then, pass in information about how to patch.
+          patch_root=options.patch_root,
+          issue=options.issue,
+          patchset=options.patchset,
+          patch_url=options.patch_url,
+          rietveld_server=options.rietveld_server,
+          gerrit_repo=options.gerrit_repo,
+          gerrit_ref=options.gerrit_ref,
+          revision_mapping=options.revision_mapping,
+          apply_issue_email_file=options.apply_issue_email_file,
+          apply_issue_key_file=options.apply_issue_key_file,
+
+          # For official builders.
+          buildspec=buildspec,
+          gyp_env=options.gyp_env,
+          runhooks=not options.no_runhooks,
+
+          # Finally, extra configurations such as shallowness of the clone.
+          shallow=options.shallow,
+          refs=options.refs)
+      gclient_output = ensure_checkout(**checkout_parameters)
+    except GclientSyncFailed:
+      print 'We failed gclient sync, lets delete the checkout and retry.'
+      ensure_no_checkout(dir_names, '*')
+      gclient_output = ensure_checkout(**checkout_parameters)
+  except PatchFailed as e:
+    if options.output_json:
+      # Tell recipes information such as root, got_revision, etc.
+      emit_json(options.output_json,
+                did_run=True,
+                root=first_sln,
+                log_lines=[('patch error', e.output),],
+                patch_apply_return_code=e.code,
+                patch_root=options.patch_root,
+                patch_failure=True,
+                step_text='%s PATCH FAILED' % step_text,
+                fixed_revisions=revisions)
+    else:
+      # If we're not on recipes, tell annotator about our got_revisions.
+      emit_log_lines('patch error', e.output)
+      print '@@@STEP_TEXT@%s PATCH FAILED@@@' % step_text
+    raise
+
+  # Revision is an svn revision, unless it's a git master.
+  use_svn_rev = master not in GIT_MASTERS
+
+  # Take care of got_revisions outputs.
+  revision_mapping = dict(GOT_REVISION_MAPPINGS.get(svn_root, {}))
+  if options.revision_mapping:
+    revision_mapping.update(options.revision_mapping)
+
+  # If the repo is not in the default GOT_REVISION_MAPPINGS and no
+  # revision_mapping were specified on the command line then
+  # default to setting 'got_revision' based on the first solution.
+  if not revision_mapping:
+    revision_mapping[first_sln] = 'got_revision'
+
+  got_revisions = parse_got_revision(gclient_output, revision_mapping,
+                                     use_svn_rev)
+
+  if not got_revisions:
+    # TODO(hinoka): We should probably bail out here, but in the interest
+    # of giving mis-configured bots some time to get fixed use a dummy
+    # revision here.
+    got_revisions = { 'got_revision': 'BOT_UPDATE_NO_REV_FOUND' }
+    #raise Exception('No got_revision(s) found in gclient output')
+
+  if options.output_json:
+    manifest = create_manifest() if options.output_manifest else None
+    # Tell recipes information such as root, got_revision, etc.
+    emit_json(options.output_json,
+              did_run=True,
+              root=first_sln,
+              patch_root=options.patch_root,
+              step_text=step_text,
+              fixed_revisions=revisions,
+              properties=got_revisions,
+              manifest=manifest)
+  else:
+    # If we're not on recipes, tell annotator about our got_revisions.
+    emit_properties(got_revisions)
+
+
+def print_help_text(force, output_json, active, master, builder, slave):
+  """Print helpful messages to tell devs whats going on."""
+  if force and output_json:
+    recipe_force = 'Forced on by recipes'
+  elif active and output_json:
+    recipe_force = 'Off by recipes, but forced on by bot update'
+  elif not active and output_json:
+    recipe_force = 'Forced off by recipes'
+  else:
+    recipe_force = 'N/A. Was not called by recipes'
+
+  print BOT_UPDATE_MESSAGE % {
+    'master': master or 'Not specified',
+    'builder': builder or 'Not specified',
+    'slave': slave or 'Not specified',
+    'recipe': recipe_force,
+    'CURRENT_DIR': CURRENT_DIR,
+    'BUILDER_DIR': BUILDER_DIR,
+    'SLAVE_DIR': SLAVE_DIR,
+    'THIS_DIR': THIS_DIR,
+    'SCRIPTS_DIR': SCRIPTS_DIR,
+    'BUILD_DIR': BUILD_DIR,
+    'ROOT_DIR': ROOT_DIR,
+    'DEPOT_TOOLS_DIR': DEPOT_TOOLS_DIR,
+  },
+  print ACTIVATED_MESSAGE if active else NOT_ACTIVATED_MESSAGE
+
+
+def main():
+  # Get inputs.
+  options, _ = parse_args()
+  builder = options.builder_name
+  slave = options.slave_name
+  master = options.master
+
+  # Check if this script should activate or not.
+  active = check_valid_host(master, builder, slave) or options.force or False
+
+  # Print a helpful message to tell developers whats going on with this step.
+  print_help_text(
+      options.force, options.output_json, active, master, builder, slave)
+
+  # Parse, munipulate, and print the gclient solutions.
+  specs = {}
+  exec(options.specs, specs)
+  svn_solutions = specs.get('solutions', [])
+  git_slns, svn_root, buildspec = solutions_to_git(svn_solutions)
+  options.revision = maybe_ignore_revision(options.revision, buildspec)
+
+  solutions_printer(git_slns)
+
+  try:
+    # Dun dun dun, the main part of bot_update.
+    revisions, step_text = prepare(options, git_slns, active)
+    checkout(options, git_slns, specs, buildspec, master, svn_root, revisions,
+             step_text)
+
+  except Inactive:
+    # Not active, should count as passing.
+    pass
+  except PatchFailed as e:
+    emit_flag(options.flag_file)
+    # Return a specific non-zero exit code for patch failure (because it is
+    # a failure), but make it different than other failures to distinguish
+    # between infra failures (independent from patch author), and patch
+    # failures (that patch author can fix). However, PatchFailure due to
+    # download patch failure is still an infra problem.
+    if e.code == 3:
+      # Patch download problem.
+      return 87
+    # Genuine patch problem.
+    return 88
+  except Exception:
+    # Unexpected failure.
+    emit_flag(options.flag_file)
+    raise
+  else:
+    emit_flag(options.flag_file)
+
+
+if __name__ == '__main__':
+  sys.exit(main())