#!/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'),
        path.join(THIS_DIR,  # resources
                  '..',      # bot_update
                  '..',      # recipe_modules
                  '..',      # depot_tools
                  '..',      # .recipe_deps
                  '..',      # slave
                  '..',      # scripts
                  '..',      # build_internal
                  '..',      # ROOT_DIR
                  'build',
                  'scripts'),
        path.join(SLAVE_DIR, '..', 'build', '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.v8.ports',
    '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',
    'client.v8.ports',
    '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')
GIT_CACHE_PATH = path.join(DEPOT_TOOLS_DIR, 'git_cache.py')

# 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, git_cache_dir):
  return GCLIENT_TEMPLATE % {
      'solutions': pprint.pformat(solutions, indent=4),
      'cache_dir': '"%s"' % git_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, git_cache_dir):
  """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, git_cache_dir))


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, git_cache_dir):
  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', git_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, git_cache_dir):
  build_dir = os.getcwd()
  # Before we do anything, break all git_cache locks.
  if path.isdir(git_cache_dir):
    git('cache', 'unlock', '-vv', '--force', '--all',
        '--cache-dir', git_cache_dir)
    for item in os.listdir(git_cache_dir):
      filename = os.path.join(git_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', git_cache_dir] + s + [url])
      for ref in refs:
        populate_cmd.extend(['--ref', ref])
      git(*populate_cmd)
      mirror_dir = git(
          'cache', 'exists', '--quiet',
          '--cache-dir', git_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])

  # TODO(kjellander): Remove this hack when http://crbug.com/611808 is fixed.
  if root == 'src/third_party/webrtc':
    cmd.extend(['--extra_patchlevel=1'])

  # 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_reset):
  gerrit_repo = gerrit_repo or 'origin'
  assert gerrit_ref
  print '===Applying gerrit ref==='
  print 'Repo is %r, ref is %r, root is %r' % (gerrit_repo, gerrit_ref, root)
  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)
    if gerrit_reset:
      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, git_cache_dir,
                    gerrit_reset):
  # 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, git_cache_dir)

  patches = None
  if patch_url:
    patches = get_svn_patch(patch_url)

  print '===Processing patch solutions==='
  already_patched = []
  patch_root = patch_root or ''
  print 'Patch root is %r' % patch_root
  for solution in solutions:
    print 'Processing solution %r' % solution['name']
    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('/')
      print '  relative root is %r, target is %r' % (relative_root, target)
      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, git_cache_dir)

  # Ensure our build/ directory is set up with the correct .gclient file.
  gclient_configure(solutions, target_os, target_os_only, git_cache_dir)

  # 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, gerrit_reset)

  # 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, git_cache_dir)

  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('--gerrit_no_reset', action='store_true',
                   help='Bypass calling reset after applying a gerrit ref.')
  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/*')
  parse.add_option('--git-cache-dir', default=path.join(SLAVE_DIR, 'cache_dir'),
                   help='Path to git cache directory.')


  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),)
    )

  # 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'):
    options.git_cache_dir = options.git_cache_dir.replace('\\', '\\\\')

  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,
          git_cache_dir=options.git_cache_dir,
          gerrit_reset=not options.gerrit_no_reset)
      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())
