#!/usr/bin/env python
# Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
#
# Use of this source code is governed by a BSD-style license
# that can be found in the LICENSE file in the root of the source
# tree. An additional intellectual property rights grant can be found
# in the file PATENTS.  All contributing project authors may
# be found in the AUTHORS file in the root of the source tree.

"""MB - the Meta-Build wrapper around GN.

MB is a wrapper script for GN that can be used to generate build files
for sets of canned configurations and analyze them.
"""

from __future__ import print_function

import argparse
import ast
import errno
import json
import os
import pipes
import pprint
import re
import shutil
import sys
import subprocess
import tempfile
import traceback
try:
  from urllib2 import urlopen  # for Python2
except ImportError:
  from urllib.request import urlopen  # for Python3

SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
SRC_DIR = os.path.dirname(os.path.dirname(SCRIPT_DIR))
sys.path = [os.path.join(SRC_DIR, 'build')] + sys.path

import gn_helpers


def main(args):
  mbw = MetaBuildWrapper()
  return mbw.Main(args)


class MetaBuildWrapper(object):
  def __init__(self):
    self.src_dir = SRC_DIR
    self.default_config = os.path.join(SCRIPT_DIR, 'mb_config.pyl')
    self.default_isolate_map = os.path.join(SCRIPT_DIR, 'gn_isolate_map.pyl')
    self.executable = sys.executable
    self.platform = sys.platform
    self.sep = os.sep
    self.args = argparse.Namespace()
    self.configs = {}
    self.builder_groups = {}
    self.mixins = {}
    self.isolate_exe = 'isolate.exe' if self.platform.startswith(
        'win') else 'isolate'

  def Main(self, args):
    self.ParseArgs(args)
    try:
      ret = self.args.func()
      if ret:
        self.DumpInputFiles()
      return ret
    except KeyboardInterrupt:
      self.Print('interrupted, exiting')
      return 130
    except Exception:
      self.DumpInputFiles()
      s = traceback.format_exc()
      for l in s.splitlines():
        self.Print(l)
      return 1

  def ParseArgs(self, argv):
    def AddCommonOptions(subp):
      subp.add_argument('-b',
                        '--builder',
                        help='builder name to look up config from')
      subp.add_argument('-m',
                        '--builder-group',
                        help='builder group name to look up config from')
      subp.add_argument('-c', '--config', help='configuration to analyze')
      subp.add_argument('--phase',
                        help='optional phase name (used when builders '
                        'do multiple compiles with different '
                        'arguments in a single build)')
      subp.add_argument('-f',
                        '--config-file',
                        metavar='PATH',
                        default=self.default_config,
                        help='path to config file '
                        '(default is %(default)s)')
      subp.add_argument('-i',
                        '--isolate-map-file',
                        metavar='PATH',
                        default=self.default_isolate_map,
                        help='path to isolate map file '
                        '(default is %(default)s)')
      subp.add_argument('-r',
                        '--realm',
                        default='webrtc:try',
                        help='optional LUCI realm to use (for example '
                        'when triggering tasks on Swarming)')
      subp.add_argument('-g', '--goma-dir', help='path to goma directory')
      subp.add_argument('--android-version-code',
                        help='Sets GN arg android_default_version_code')
      subp.add_argument('--android-version-name',
                        help='Sets GN arg android_default_version_name')
      subp.add_argument('-n',
                        '--dryrun',
                        action='store_true',
                        help='Do a dry run (i.e., do nothing, just '
                        'print the commands that will run)')
      subp.add_argument('-v',
                        '--verbose',
                        action='store_true',
                        help='verbose logging')

    parser = argparse.ArgumentParser(prog='mb')
    subps = parser.add_subparsers()

    subp = subps.add_parser('analyze',
                            help='analyze whether changes to a set of '
                            'files will cause a set of binaries '
                            'to be rebuilt.')
    AddCommonOptions(subp)
    subp.add_argument('path', nargs=1, help='path build was generated into.')
    subp.add_argument('input_path',
                      nargs=1,
                      help='path to a file containing the input '
                      'arguments as a JSON object.')
    subp.add_argument('output_path',
                      nargs=1,
                      help='path to a file containing the output '
                      'arguments as a JSON object.')
    subp.add_argument('--json-output', help='Write errors to json.output')
    subp.set_defaults(func=self.CmdAnalyze)

    subp = subps.add_parser('export',
                            help='print out the expanded configuration for'
                            'each builder as a JSON object')
    subp.add_argument('-f',
                      '--config-file',
                      metavar='PATH',
                      default=self.default_config,
                      help='path to config file (default is %(default)s)')
    subp.add_argument('-g', '--goma-dir', help='path to goma directory')
    subp.set_defaults(func=self.CmdExport)

    subp = subps.add_parser('gen', help='generate a new set of build files')
    AddCommonOptions(subp)
    subp.add_argument('--swarming-targets-file',
                      help='save runtime dependencies for targets listed '
                      'in file.')
    subp.add_argument('--json-output', help='Write errors to json.output')
    subp.add_argument('path', nargs=1, help='path to generate build into')
    subp.set_defaults(func=self.CmdGen)

    subp = subps.add_parser('isolate',
                            help='generate the .isolate files for a given'
                            'binary')
    AddCommonOptions(subp)
    subp.add_argument('path', nargs=1, help='path build was generated into')
    subp.add_argument('target',
                      nargs=1,
                      help='ninja target to generate the isolate for')
    subp.set_defaults(func=self.CmdIsolate)

    subp = subps.add_parser('lookup',
                            help='look up the command for a given config '
                            'or builder')
    AddCommonOptions(subp)
    subp.add_argument('--quiet',
                      default=False,
                      action='store_true',
                      help='Print out just the arguments, do '
                      'not emulate the output of the gen subcommand.')
    subp.set_defaults(func=self.CmdLookup)

    subp = subps.add_parser(
        'run',
        help='build and run the isolated version of a '
        'binary',
        formatter_class=argparse.RawDescriptionHelpFormatter)
    subp.description = (
        'Build, isolate, and run the given binary with the command line\n'
        'listed in the isolate. You may pass extra arguments after the\n'
        'target; use "--" if the extra arguments need to include switches.'
        '\n\n'
        'Examples:\n'
        '\n'
        '  % tools/mb/mb.py run -m chromium.linux -b "Linux Builder" \\\n'
        '    //out/Default content_browsertests\n'
        '\n'
        '  % tools/mb/mb.py run out/Default content_browsertests\n'
        '\n'
        '  % tools/mb/mb.py run out/Default content_browsertests -- \\\n'
        '    --test-launcher-retry-limit=0'
        '\n')
    AddCommonOptions(subp)
    subp.add_argument('-j',
                      '--jobs',
                      dest='jobs',
                      type=int,
                      help='Number of jobs to pass to ninja')
    subp.add_argument('--no-build',
                      dest='build',
                      default=True,
                      action='store_false',
                      help='Do not build, just isolate and run')
    subp.add_argument('path',
                      nargs=1,
                      help=('path to generate build into (or use).'
                            ' This can be either a regular path or a '
                            'GN-style source-relative path like '
                            '//out/Default.'))
    subp.add_argument('-s',
                      '--swarmed',
                      action='store_true',
                      help='Run under swarming')
    subp.add_argument('-d',
                      '--dimension',
                      default=[],
                      action='append',
                      nargs=2,
                      dest='dimensions',
                      metavar='FOO bar',
                      help='dimension to filter on')
    subp.add_argument('target', nargs=1, help='ninja target to build and run')
    subp.add_argument('extra_args',
                      nargs='*',
                      help=('extra args to pass to the isolate to run. '
                            'Use "--" as the first arg if you need to '
                            'pass switches'))
    subp.set_defaults(func=self.CmdRun)

    subp = subps.add_parser('validate', help='validate the config file')
    subp.add_argument('-f',
                      '--config-file',
                      metavar='PATH',
                      default=self.default_config,
                      help='path to config file (default is %(default)s)')
    subp.set_defaults(func=self.CmdValidate)

    subp = subps.add_parser('help', help='Get help on a subcommand.')
    subp.add_argument(nargs='?',
                      action='store',
                      dest='subcommand',
                      help='The command to get help for.')
    subp.set_defaults(func=self.CmdHelp)

    self.args = parser.parse_args(argv)

  def DumpInputFiles(self):
    def DumpContentsOfFilePassedTo(arg_name, path):
      if path and self.Exists(path):
        self.Print("\n# To recreate the file passed to %s:" % arg_name)
        self.Print("%% cat > %s <<EOF" % path)
        contents = self.ReadFile(path)
        self.Print(contents)
        self.Print("EOF\n%\n")

    if getattr(self.args, 'input_path', None):
      DumpContentsOfFilePassedTo('argv[0] (input_path)',
                                 self.args.input_path[0])
    if getattr(self.args, 'swarming_targets_file', None):
      DumpContentsOfFilePassedTo('--swarming-targets-file',
                                 self.args.swarming_targets_file)

  def CmdAnalyze(self):
    vals = self.Lookup()
    return self.RunGNAnalyze(vals)

  def CmdExport(self):
    self.ReadConfigFile()
    obj = {}
    for builder_group, builders in self.builder_groups.items():
      obj[builder_group] = {}
      for builder in builders:
        config = self.builder_groups[builder_group][builder]
        if not config:
          continue

        if isinstance(config, dict):
          args = {
              k: self.FlattenConfig(v)['gn_args']
              for k, v in config.items()
          }
        elif config.startswith('//'):
          args = config
        else:
          args = self.FlattenConfig(config)['gn_args']
          if 'error' in args:
            continue

        obj[builder_group][builder] = args

    # Dump object and trim trailing whitespace.
    s = '\n'.join(
        l.rstrip()
        for l in json.dumps(obj, sort_keys=True, indent=2).splitlines())
    self.Print(s)
    return 0

  def CmdGen(self):
    vals = self.Lookup()
    return self.RunGNGen(vals)

  def CmdHelp(self):
    if self.args.subcommand:
      self.ParseArgs([self.args.subcommand, '--help'])
    else:
      self.ParseArgs(['--help'])

  def CmdIsolate(self):
    vals = self.GetConfig()
    if not vals:
      return 1
    return self.RunGNIsolate(vals)

  def CmdLookup(self):
    vals = self.Lookup()
    gn_args = self.GNArgs(vals)
    if self.args.quiet:
      self.Print(gn_args, end='')
    else:
      cmd = self.GNCmd('gen', '_path_')
      self.Print('\nWriting """\\\n%s""" to _path_/args.gn.\n' % gn_args)
      env = None

      self.PrintCmd(cmd, env)
    return 0

  def CmdRun(self):
    vals = self.GetConfig()
    if not vals:
      return 1

    build_dir = self.args.path[0]
    target = self.args.target[0]

    if self.args.build:
      ret = self.Build(target)
      if ret:
        return ret
    ret = self.RunGNIsolate(vals)
    if ret:
      return ret

    if self.args.swarmed:
      cmd, _ = self.GetSwarmingCommand(self.args.target[0], vals)
      return self._RunUnderSwarming(build_dir, target, cmd)
    return self._RunLocallyIsolated(build_dir, target)

  def _RunUnderSwarming(self, build_dir, target, isolate_cmd):
    cas_instance = 'chromium-swarm'
    swarming_server = 'chromium-swarm.appspot.com'
    # TODO(dpranke): Look up the information for the target in
    # the //testing/buildbot.json file, if possible, so that we
    # can determine the isolate target, command line, and additional
    # swarming parameters, if possible.
    #
    # TODO(dpranke): Also, add support for sharding and merging results.
    dimensions = []
    for k, v in self.args.dimensions:
      dimensions += ['-d', '%s=%s' % (k, v)]

    archive_json_path = self.ToSrcRelPath('%s/%s.archive.json' %
                                          (build_dir, target))
    cmd = [
        self.PathJoin(self.src_dir, 'tools', 'luci-go', self.isolate_exe),
        'archive',
        '-i',
        self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
        '-cas-instance',
        cas_instance,
        '-dump-json',
        archive_json_path,
    ]

    # Talking to the isolateserver may fail because we're not logged in.
    # We trap the command explicitly and rewrite the error output so that
    # the error message is actually correct for a Chromium check out.
    self.PrintCmd(cmd, env=None)
    ret, out, err = self.Run(cmd, force_verbose=False)
    if ret:
      self.Print('  -> returned %d' % ret)
      if out:
        self.Print(out, end='')
      if err:
        self.Print(err, end='', file=sys.stderr)

      return ret

    try:
      archive_hashes = json.loads(self.ReadFile(archive_json_path))
    except Exception:
      self.Print('Failed to read JSON file "%s"' % archive_json_path,
                 file=sys.stderr)
      return 1
    try:
      cas_digest = archive_hashes[target]
    except Exception:
      self.Print('Cannot find hash for "%s" in "%s", file content: %s' %
                 (target, archive_json_path, archive_hashes),
                 file=sys.stderr)
      return 1

    try:
      json_dir = self.TempDir()
      json_file = self.PathJoin(json_dir, 'task.json')

      cmd = [
          self.PathJoin('tools', 'luci-go', 'swarming'),
          'trigger',
          '-realm',
          self.args.realm,
          '-digest',
          cas_digest,
          '-server',
          swarming_server,
          '-tag=purpose:user-debug-mb',
          '-relative-cwd',
          self.ToSrcRelPath(build_dir),
          '-dump-json',
          json_file,
      ] + dimensions + ['--'] + list(isolate_cmd)

      if self.args.extra_args:
        cmd += ['--'] + self.args.extra_args
      self.Print('')
      ret, _, _ = self.Run(cmd, force_verbose=True, buffer_output=False)
      if ret:
        return ret
      task_json = self.ReadFile(json_file)
      task_id = json.loads(task_json)["tasks"][0]['task_id']
    finally:
      if json_dir:
        self.RemoveDirectory(json_dir)

    cmd = [
        self.PathJoin('tools', 'luci-go', 'swarming'),
        'collect',
        '-server',
        swarming_server,
        '-task-output-stdout=console',
        task_id,
    ]
    ret, _, _ = self.Run(cmd, force_verbose=True, buffer_output=False)
    return ret

  def _RunLocallyIsolated(self, build_dir, target):
    cmd = [
        self.PathJoin(self.src_dir, 'tools', 'luci-go', self.isolate_exe),
        'run',
        '-i',
        self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
    ]
    if self.args.extra_args:
      cmd += ['--'] + self.args.extra_args
    ret, _, _ = self.Run(cmd, force_verbose=True, buffer_output=False)
    return ret

  def CmdValidate(self, print_ok=True):
    errs = []

    # Read the file to make sure it parses.
    self.ReadConfigFile()

    # Build a list of all of the configs referenced by builders.
    all_configs = {}
    for builder_group in self.builder_groups:
      for config in self.builder_groups[builder_group].values():
        if isinstance(config, dict):
          for c in config.values():
            all_configs[c] = builder_group
        else:
          all_configs[config] = builder_group

    # Check that every referenced args file or config actually exists.
    for config, loc in all_configs.items():
      if config.startswith('//'):
        if not self.Exists(self.ToAbsPath(config)):
          errs.append('Unknown args file "%s" referenced from "%s".' %
                      (config, loc))
      elif not config in self.configs:
        errs.append('Unknown config "%s" referenced from "%s".' % (config, loc))

    # Check that every actual config is actually referenced.
    for config in self.configs:
      if not config in all_configs:
        errs.append('Unused config "%s".' % config)

    # Figure out the whole list of mixins, and check that every mixin
    # listed by a config or another mixin actually exists.
    referenced_mixins = set()
    for config, mixins in self.configs.items():
      for mixin in mixins:
        if not mixin in self.mixins:
          errs.append('Unknown mixin "%s" referenced by config "%s".' %
                      (mixin, config))
        referenced_mixins.add(mixin)

    for mixin in self.mixins:
      for sub_mixin in self.mixins[mixin].get('mixins', []):
        if not sub_mixin in self.mixins:
          errs.append('Unknown mixin "%s" referenced by mixin "%s".' %
                      (sub_mixin, mixin))
        referenced_mixins.add(sub_mixin)

    # Check that every mixin defined is actually referenced somewhere.
    for mixin in self.mixins:
      if not mixin in referenced_mixins:
        errs.append('Unreferenced mixin "%s".' % mixin)

    if errs:
      raise MBErr(('mb config file %s has problems:' % self.args.config_file) +
                  '\n  ' + '\n  '.join(errs))

    if print_ok:
      self.Print('mb config file %s looks ok.' % self.args.config_file)
    return 0

  def GetConfig(self):
    build_dir = self.args.path[0]

    vals = self.DefaultVals()
    if self.args.builder or self.args.builder_group or self.args.config:
      vals = self.Lookup()
      # Re-run gn gen in order to ensure the config is consistent with
      # the build dir.
      self.RunGNGen(vals)
      return vals

    toolchain_path = self.PathJoin(self.ToAbsPath(build_dir), 'toolchain.ninja')
    if not self.Exists(toolchain_path):
      self.Print('Must either specify a path to an existing GN build '
                 'dir or pass in a -m/-b pair or a -c flag to specify '
                 'the configuration')
      return {}

    vals['gn_args'] = self.GNArgsFromDir(build_dir)
    return vals

  def GNArgsFromDir(self, build_dir):
    args_contents = ""
    gn_args_path = self.PathJoin(self.ToAbsPath(build_dir), 'args.gn')
    if self.Exists(gn_args_path):
      args_contents = self.ReadFile(gn_args_path)
    gn_args = []
    for l in args_contents.splitlines():
      fields = l.split(' ')
      name = fields[0]
      val = ' '.join(fields[2:])
      gn_args.append('%s=%s' % (name, val))

    return ' '.join(gn_args)

  def Lookup(self):
    self.ReadConfigFile()
    config = self.ConfigFromArgs()
    if config.startswith('//'):
      if not self.Exists(self.ToAbsPath(config)):
        raise MBErr('args file "%s" not found' % config)
      vals = self.DefaultVals()
      vals['args_file'] = config
    else:
      if not config in self.configs:
        raise MBErr('Config "%s" not found in %s' %
                    (config, self.args.config_file))
      vals = self.FlattenConfig(config)
    return vals

  def ReadConfigFile(self):
    if not self.Exists(self.args.config_file):
      raise MBErr('config file not found at %s' % self.args.config_file)

    try:
      contents = ast.literal_eval(self.ReadFile(self.args.config_file))
    except SyntaxError as e:
      raise MBErr('Failed to parse config file "%s": %s' %
                  (self.args.config_file, e))

    self.configs = contents['configs']
    self.builder_groups = contents['builder_groups']
    self.mixins = contents['mixins']

  def ReadIsolateMap(self):
    isolate_map = self.args.isolate_map_file
    if not self.Exists(isolate_map):
      raise MBErr('isolate map file not found at %s' % isolate_map)
    try:
      return ast.literal_eval(self.ReadFile(isolate_map))
    except SyntaxError as e:
      raise MBErr('Failed to parse isolate map file "%s": %s' %
                  (isolate_map, e))

  def ConfigFromArgs(self):
    if self.args.config:
      if self.args.builder_group or self.args.builder:
        raise MBErr('Can not specific both -c/--config and '
                    '-m/--builder-group or -b/--builder')

      return self.args.config

    if not self.args.builder_group or not self.args.builder:
      raise MBErr('Must specify either -c/--config or '
                  '(-m/--builder-group and -b/--builder)')

    if not self.args.builder_group in self.builder_groups:
      raise MBErr('Master name "%s" not found in "%s"' %
                  (self.args.builder_group, self.args.config_file))

    if not self.args.builder in self.builder_groups[self.args.builder_group]:
      raise MBErr(
          'Builder name "%s"  not found under builder_groups[%s] in "%s"' %
          (self.args.builder, self.args.builder_group, self.args.config_file))

    config = (self.builder_groups[self.args.builder_group][self.args.builder])
    if isinstance(config, dict):
      if self.args.phase is None:
        raise MBErr('Must specify a build --phase for %s on %s' %
                    (self.args.builder, self.args.builder_group))
      phase = str(self.args.phase)
      if phase not in config:
        raise MBErr('Phase %s doesn\'t exist for %s on %s' %
                    (phase, self.args.builder, self.args.builder_group))
      return config[phase]

    if self.args.phase is not None:
      raise MBErr('Must not specify a build --phase for %s on %s' %
                  (self.args.builder, self.args.builder_group))
    return config

  def FlattenConfig(self, config):
    mixins = self.configs[config]
    vals = self.DefaultVals()

    visited = []
    self.FlattenMixins(mixins, vals, visited)
    return vals

  @staticmethod
  def DefaultVals():
    return {
        'args_file': '',
        'cros_passthrough': False,
        'gn_args': '',
    }

  def FlattenMixins(self, mixins, vals, visited):
    for m in mixins:
      if m not in self.mixins:
        raise MBErr('Unknown mixin "%s"' % m)

      visited.append(m)

      mixin_vals = self.mixins[m]

      if 'cros_passthrough' in mixin_vals:
        vals['cros_passthrough'] = mixin_vals['cros_passthrough']
      if 'gn_args' in mixin_vals:
        if vals['gn_args']:
          vals['gn_args'] += ' ' + mixin_vals['gn_args']
        else:
          vals['gn_args'] = mixin_vals['gn_args']

      if 'mixins' in mixin_vals:
        self.FlattenMixins(mixin_vals['mixins'], vals, visited)
    return vals

  def RunGNGen(self, vals):
    build_dir = self.args.path[0]

    cmd = self.GNCmd('gen', build_dir, '--check')
    gn_args = self.GNArgs(vals)

    # Since GN hasn't run yet, the build directory may not even exist.
    self.MaybeMakeDirectory(self.ToAbsPath(build_dir))

    gn_args_path = self.ToAbsPath(build_dir, 'args.gn')
    self.WriteFile(gn_args_path, gn_args, force_verbose=True)

    swarming_targets = set()
    if getattr(self.args, 'swarming_targets_file', None):
      # We need GN to generate the list of runtime dependencies for
      # the compile targets listed (one per line) in the file so
      # we can run them via swarming. We use gn_isolate_map.pyl to
      # convert the compile targets to the matching GN labels.
      path = self.args.swarming_targets_file
      if not self.Exists(path):
        self.WriteFailureAndRaise('"%s" does not exist' % path,
                                  output_path=None)
      contents = self.ReadFile(path)
      swarming_targets = set(contents.splitlines())

      isolate_map = self.ReadIsolateMap()
      err, labels = self.MapTargetsToLabels(isolate_map, swarming_targets)
      if err:
        raise MBErr(err)

      gn_runtime_deps_path = self.ToAbsPath(build_dir, 'runtime_deps')
      self.WriteFile(gn_runtime_deps_path, '\n'.join(labels) + '\n')
      cmd.append('--runtime-deps-list-file=%s' % gn_runtime_deps_path)

    ret, output, _ = self.Run(cmd)
    if ret:
      if self.args.json_output:
        # write errors to json.output
        self.WriteJSON({'output': output}, self.args.json_output)
      # If `gn gen` failed, we should exit early rather than trying to
      # generate isolates. Run() will have already logged any error
      # output.
      self.Print('GN gen failed: %d' % ret)
      return ret

    android = 'target_os="android"' in vals['gn_args']
    for target in swarming_targets:
      if android:
        # Android targets may be either android_apk or executable. The
        # former will result in runtime_deps associated with the stamp
        # file, while the latter will result in runtime_deps associated
        # with the executable.
        label = isolate_map[target]['label']
        runtime_deps_targets = [
            target + '.runtime_deps',
            'obj/%s.stamp.runtime_deps' % label.replace(':', '/')
        ]
      elif isolate_map[target]['type'] == 'gpu_browser_test':
        if self.platform == 'win32':
          runtime_deps_targets = ['browser_tests.exe.runtime_deps']
        else:
          runtime_deps_targets = ['browser_tests.runtime_deps']
      elif isolate_map[target]['type'] == 'script':
        label = isolate_map[target]['label'].split(':')[1]
        runtime_deps_targets = ['%s.runtime_deps' % label]
        if self.platform == 'win32':
          runtime_deps_targets += [label + '.exe.runtime_deps']
        else:
          runtime_deps_targets += [label + '.runtime_deps']
      elif self.platform == 'win32':
        runtime_deps_targets = [target + '.exe.runtime_deps']
      else:
        runtime_deps_targets = [target + '.runtime_deps']

      for r in runtime_deps_targets:
        runtime_deps_path = self.ToAbsPath(build_dir, r)
        if self.Exists(runtime_deps_path):
          break
      else:
        raise MBErr('did not generate any of %s' %
                    ', '.join(runtime_deps_targets))

      command, extra_files = self.GetSwarmingCommand(target, vals)

      runtime_deps = self.ReadFile(runtime_deps_path).splitlines()

      self.WriteIsolateFiles(build_dir, command, target, runtime_deps,
                             extra_files)

    return 0

  def RunGNIsolate(self, vals):
    target = self.args.target[0]
    isolate_map = self.ReadIsolateMap()
    err, labels = self.MapTargetsToLabels(isolate_map, [target])
    if err:
      raise MBErr(err)
    label = labels[0]

    build_dir = self.args.path[0]
    command, extra_files = self.GetSwarmingCommand(target, vals)

    cmd = self.GNCmd('desc', build_dir, label, 'runtime_deps')
    ret, out, _ = self.Call(cmd)
    if ret:
      if out:
        self.Print(out)
      return ret

    runtime_deps = out.splitlines()

    self.WriteIsolateFiles(build_dir, command, target, runtime_deps,
                           extra_files)

    ret, _, _ = self.Run([
        self.PathJoin(self.src_dir, 'tools', 'luci-go', self.isolate_exe),
        'check', '-i',
        self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target))
    ],
                         buffer_output=False)

    return ret

  def WriteIsolateFiles(self, build_dir, command, target, runtime_deps,
                        extra_files):
    isolate_path = self.ToAbsPath(build_dir, target + '.isolate')
    self.WriteFile(
        isolate_path,
        pprint.pformat({
            'variables': {
                'command': command,
                'files': sorted(runtime_deps + extra_files),
            }
        }) + '\n')

    self.WriteJSON(
        {
            'args': [
                '--isolate',
                self.ToSrcRelPath('%s/%s.isolate' % (build_dir, target)),
            ],
            'dir':
            self.src_dir,
            'version':
            1,
        },
        isolate_path + 'd.gen.json',
    )

  @staticmethod
  def MapTargetsToLabels(isolate_map, targets):
    labels = []
    err = ''

    def StripTestSuffixes(target):
      for suffix in ('_apk_run', '_apk', '_run'):
        if target.endswith(suffix):
          return target[:-len(suffix)], suffix
      return None, None

    for target in targets:
      if target == 'all':
        labels.append(target)
      elif target.startswith('//'):
        labels.append(target)
      else:
        if target in isolate_map:
          stripped_target, suffix = target, ''
        else:
          stripped_target, suffix = StripTestSuffixes(target)
        if stripped_target in isolate_map:
          if isolate_map[stripped_target]['type'] == 'unknown':
            err += ('test target "%s" type is unknown\n' % target)
          else:
            labels.append(isolate_map[stripped_target]['label'] + suffix)
        else:
          err += ('target "%s" not found in '
                  '//testing/buildbot/gn_isolate_map.pyl\n' % target)

    return err, labels

  def GNCmd(self, subcommand, path, *args):
    if self.platform.startswith('linux'):
      subdir, exe = 'linux64', 'gn'
    elif self.platform == 'darwin':
      subdir, exe = 'mac', 'gn'
    else:
      subdir, exe = 'win', 'gn.exe'

    gn_path = self.PathJoin(self.src_dir, 'buildtools', subdir, exe)
    return [gn_path, subcommand, path] + list(args)

  def GNArgs(self, vals):
    if vals['cros_passthrough']:
      if not 'GN_ARGS' in os.environ:
        raise MBErr('MB is expecting GN_ARGS to be in the environment')
      gn_args = os.environ['GN_ARGS']
      if not re.search('target_os.*=.*"chromeos"', gn_args):
        raise MBErr('GN_ARGS is missing target_os = "chromeos": '
                    '(GN_ARGS=%s)' % gn_args)
    else:
      gn_args = vals['gn_args']

    if self.args.goma_dir:
      gn_args += ' goma_dir="%s"' % self.args.goma_dir

    android_version_code = self.args.android_version_code
    if android_version_code:
      gn_args += (' android_default_version_code="%s"' % android_version_code)

    android_version_name = self.args.android_version_name
    if android_version_name:
      gn_args += (' android_default_version_name="%s"' % android_version_name)

    # Canonicalize the arg string into a sorted, newline-separated list
    # of key-value pairs, and de-dup the keys if need be so that only
    # the last instance of each arg is listed.
    gn_args = gn_helpers.ToGNString(gn_helpers.FromGNArgs(gn_args))

    args_file = vals.get('args_file', None)
    if args_file:
      gn_args = ('import("%s")\n' % vals['args_file']) + gn_args
    return gn_args

  def GetSwarmingCommand(self, target, vals):
    isolate_map = self.ReadIsolateMap()
    test_type = isolate_map[target]['type']

    is_android = 'target_os="android"' in vals['gn_args']
    is_linux = self.platform.startswith('linux') and not is_android

    if test_type == 'nontest':
      self.WriteFailureAndRaise('We should not be isolating %s.' % target,
                                output_path=None)
    if test_type not in ('console_test_launcher', 'windowed_test_launcher',
                         'non_parallel_console_test_launcher', 'raw',
                         'additional_compile_target', 'junit_test', 'script'):
      self.WriteFailureAndRaise('No command line for '
                                '%s found (test type %s).' %
                                (target, test_type),
                                output_path=None)

    cmdline = []
    extra_files = [
        '../../.vpython',
        '../../testing/test_env.py',
    ]
    vpython_exe = 'vpython'

    must_retry = False
    if test_type == 'script':
      cmdline += [
          vpython_exe,
          '../../' + self.ToSrcRelPath(isolate_map[target]['script'])
      ]
    elif is_android:
      cmdline += [
          vpython_exe, '../../build/android/test_wrapper/logdog_wrapper.py',
          '--target', target, '--logdog-bin-cmd', '../../bin/logdog_butler',
          '--logcat-output-file', '${ISOLATED_OUTDIR}/logcats',
          '--store-tombstones'
      ]
    else:
      if test_type == 'raw':
        cmdline += [vpython_exe, '../../tools_webrtc/flags_compatibility.py']
        extra_files.append('../../tools_webrtc/flags_compatibility.py')

      if isolate_map[target].get('use_webcam', False):
        cmdline += [
            vpython_exe, '../../tools_webrtc/ensure_webcam_is_running.py'
        ]
        extra_files.append('../../tools_webrtc/ensure_webcam_is_running.py')

      # is_linux uses use_ozone and x11 by default.
      use_x11 = is_linux

      xvfb = use_x11 and test_type == 'windowed_test_launcher'
      if xvfb:
        cmdline += [vpython_exe, '../../testing/xvfb.py']
        extra_files.append('../../testing/xvfb.py')
      else:
        cmdline += [vpython_exe, '../../testing/test_env.py']

      if test_type != 'raw':
        extra_files += [
            '../../third_party/gtest-parallel/gtest-parallel',
            '../../third_party/gtest-parallel/gtest_parallel.py',
            '../../tools_webrtc/gtest-parallel-wrapper.py',
        ]
        sep = '\\' if self.platform == 'win32' else '/'
        output_dir = '${ISOLATED_OUTDIR}' + sep + 'test_logs'
        test_results = '${ISOLATED_OUTDIR}' + sep + 'gtest_output.json'
        timeout = isolate_map[target].get('timeout', 900)
        cmdline += [
            '../../tools_webrtc/gtest-parallel-wrapper.py',
            '--output_dir=%s' % output_dir,
            '--dump_json_test_results=%s' % test_results,
            '--gtest_color=no',
            # We tell gtest-parallel to interrupt the test after 900
            # seconds, so it can exit cleanly and report results,
            # instead of being interrupted by swarming and not
            # reporting anything.
            '--timeout=%s' % timeout,
        ]
        if test_type == 'non_parallel_console_test_launcher':
          # Still use the gtest-parallel-wrapper.py script since we
          # need it to run tests on swarming, but don't execute tests
          # in parallel.
          cmdline.append('--workers=1')
        must_retry = True

      asan = 'is_asan=true' in vals['gn_args']
      lsan = 'is_lsan=true' in vals['gn_args']
      msan = 'is_msan=true' in vals['gn_args']
      tsan = 'is_tsan=true' in vals['gn_args']
      sanitizer = asan or lsan or msan or tsan
      if must_retry and not sanitizer:
        # Retry would hide most sanitizers detections.
        cmdline.append('--retry_failed=3')

      executable_prefix = '.\\' if self.platform == 'win32' else './'
      executable_suffix = '.exe' if self.platform == 'win32' else ''
      executable = executable_prefix + target + executable_suffix

      cmdline.append(executable)

      cmdline.extend([
          '--asan=%d' % asan,
          '--lsan=%d' % lsan,
          '--msan=%d' % msan,
          '--tsan=%d' % tsan,
      ])

    cmdline += isolate_map[target].get('args', [])

    return cmdline, extra_files

  def ToAbsPath(self, build_path, *comps):
    return self.PathJoin(self.src_dir, self.ToSrcRelPath(build_path), *comps)

  def ToSrcRelPath(self, path):
    """Returns a relative path from the top of the repo."""
    if path.startswith('//'):
      return path[2:].replace('/', self.sep)
    return self.RelPath(path, self.src_dir)

  def RunGNAnalyze(self, vals):
    # Analyze runs before 'gn gen' now, so we need to run gn gen
    # in order to ensure that we have a build directory.
    ret = self.RunGNGen(vals)
    if ret:
      return ret

    build_path = self.args.path[0]
    input_path = self.args.input_path[0]
    gn_input_path = input_path + '.gn'
    output_path = self.args.output_path[0]
    gn_output_path = output_path + '.gn'

    inp = self.ReadInputJSON(
        ['files', 'test_targets', 'additional_compile_targets'])
    if self.args.verbose:
      self.Print()
      self.Print('analyze input:')
      self.PrintJSON(inp)
      self.Print()

    # This shouldn't normally happen, but could due to unusual race
    # conditions, like a try job that gets scheduled before a patch
    # lands but runs after the patch has landed.
    if not inp['files']:
      self.Print('Warning: No files modified in patch, bailing out early.')
      self.WriteJSON(
          {
              'status': 'No dependency',
              'compile_targets': [],
              'test_targets': [],
          }, output_path)
      return 0

    gn_inp = {}
    gn_inp['files'] = ['//' + f for f in inp['files'] if not f.startswith('//')]

    isolate_map = self.ReadIsolateMap()
    err, gn_inp['additional_compile_targets'] = self.MapTargetsToLabels(
        isolate_map, inp['additional_compile_targets'])
    if err:
      raise MBErr(err)

    err, gn_inp['test_targets'] = self.MapTargetsToLabels(
        isolate_map, inp['test_targets'])
    if err:
      raise MBErr(err)
    labels_to_targets = {}
    for i, label in enumerate(gn_inp['test_targets']):
      labels_to_targets[label] = inp['test_targets'][i]

    try:
      self.WriteJSON(gn_inp, gn_input_path)
      cmd = self.GNCmd('analyze', build_path, gn_input_path, gn_output_path)
      ret, output, _ = self.Run(cmd, force_verbose=True)
      if ret:
        if self.args.json_output:
          # write errors to json.output
          self.WriteJSON({'output': output}, self.args.json_output)
        return ret

      gn_outp_str = self.ReadFile(gn_output_path)
      try:
        gn_outp = json.loads(gn_outp_str)
      except Exception as e:
        self.Print("Failed to parse the JSON string GN "
                   "returned: %s\n%s" % (repr(gn_outp_str), str(e)))
        raise

      outp = {}
      if 'status' in gn_outp:
        outp['status'] = gn_outp['status']
      if 'error' in gn_outp:
        outp['error'] = gn_outp['error']
      if 'invalid_targets' in gn_outp:
        outp['invalid_targets'] = gn_outp['invalid_targets']
      if 'compile_targets' in gn_outp:
        if 'all' in gn_outp['compile_targets']:
          outp['compile_targets'] = ['all']
        else:
          outp['compile_targets'] = [
              label.replace('//', '') for label in gn_outp['compile_targets']
          ]
      if 'test_targets' in gn_outp:
        outp['test_targets'] = [
            labels_to_targets[label] for label in gn_outp['test_targets']
        ]

      if self.args.verbose:
        self.Print()
        self.Print('analyze output:')
        self.PrintJSON(outp)
        self.Print()

      self.WriteJSON(outp, output_path)

    finally:
      if self.Exists(gn_input_path):
        self.RemoveFile(gn_input_path)
      if self.Exists(gn_output_path):
        self.RemoveFile(gn_output_path)

    return 0

  def ReadInputJSON(self, required_keys):
    path = self.args.input_path[0]
    output_path = self.args.output_path[0]
    if not self.Exists(path):
      self.WriteFailureAndRaise('"%s" does not exist' % path, output_path)

    try:
      inp = json.loads(self.ReadFile(path))
    except Exception as e:
      self.WriteFailureAndRaise(
          'Failed to read JSON input from "%s": %s' % (path, e), output_path)

    for k in required_keys:
      if not k in inp:
        self.WriteFailureAndRaise('input file is missing a "%s" key' % k,
                                  output_path)

    return inp

  def WriteFailureAndRaise(self, msg, output_path):
    if output_path:
      self.WriteJSON({'error': msg}, output_path, force_verbose=True)
    raise MBErr(msg)

  def WriteJSON(self, obj, path, force_verbose=False):
    try:
      self.WriteFile(path,
                     json.dumps(obj, indent=2, sort_keys=True) + '\n',
                     force_verbose=force_verbose)
    except Exception as e:
      raise MBErr('Error %s writing to the output path "%s"' % (e, path))

  def PrintCmd(self, cmd, env):
    if self.platform == 'win32':
      env_prefix = 'set '
      env_quoter = QuoteForSet
      shell_quoter = QuoteForCmd
    else:
      env_prefix = ''
      env_quoter = pipes.quote
      shell_quoter = pipes.quote

    var = 'LLVM_FORCE_HEAD_REVISION'
    if env and var in env:
      self.Print('%s%s=%s' % (env_prefix, var, env_quoter(env[var])))

    if cmd[0] == self.executable:
      cmd = ['python'] + cmd[1:]
    self.Print(*[shell_quoter(arg) for arg in cmd])

  def PrintJSON(self, obj):
    self.Print(json.dumps(obj, indent=2, sort_keys=True))

  def Build(self, target):
    build_dir = self.ToSrcRelPath(self.args.path[0])
    ninja_cmd = ['ninja', '-C', build_dir]
    if self.args.jobs:
      ninja_cmd.extend(['-j', '%d' % self.args.jobs])
    ninja_cmd.append(target)
    ret, _, _ = self.Run(ninja_cmd, force_verbose=False, buffer_output=False)
    return ret

  def Run(self, cmd, env=None, force_verbose=True, buffer_output=True):
    # This function largely exists so it can be overridden for testing.
    if self.args.dryrun or self.args.verbose or force_verbose:
      self.PrintCmd(cmd, env)
    if self.args.dryrun:
      return 0, '', ''

    ret, out, err = self.Call(cmd, env=env, buffer_output=buffer_output)
    if self.args.verbose or force_verbose:
      if ret:
        self.Print('  -> returned %d' % ret)
      if out:
        self.Print(out, end='')
      if err:
        self.Print(err, end='', file=sys.stderr)
    return ret, out, err

  def Call(self, cmd, env=None, buffer_output=True):
    if buffer_output:
      p = subprocess.Popen(cmd,
                           shell=False,
                           cwd=self.src_dir,
                           stdout=subprocess.PIPE,
                           stderr=subprocess.PIPE,
                           env=env)
      out, err = p.communicate()
    else:
      p = subprocess.Popen(cmd, shell=False, cwd=self.src_dir, env=env)
      p.wait()
      out = err = ''
    return p.returncode, out, err

  @staticmethod
  def ExpandUser(path):
    # This function largely exists so it can be overridden for testing.
    return os.path.expanduser(path)

  @staticmethod
  def Exists(path):
    # This function largely exists so it can be overridden for testing.
    return os.path.exists(path)

  @staticmethod
  def Fetch(url):
    # This function largely exists so it can be overridden for testing.
    f = urlopen(url)
    contents = f.read()
    f.close()
    return contents

  @staticmethod
  def MaybeMakeDirectory(path):
    try:
      os.makedirs(path)
    except OSError as e:
      if e.errno != errno.EEXIST:
        raise

  @staticmethod
  def PathJoin(*comps):
    # This function largely exists so it can be overriden for testing.
    return os.path.join(*comps)

  @staticmethod
  def Print(*args, **kwargs):
    # This function largely exists so it can be overridden for testing.
    print(*args, **kwargs)
    if kwargs.get('stream', sys.stdout) == sys.stdout:
      sys.stdout.flush()

  @staticmethod
  def ReadFile(path):
    # This function largely exists so it can be overriden for testing.
    with open(path) as fp:
      return fp.read()

  @staticmethod
  def RelPath(path, start='.'):
    # This function largely exists so it can be overriden for testing.
    return os.path.relpath(path, start)

  @staticmethod
  def RemoveFile(path):
    # This function largely exists so it can be overriden for testing.
    os.remove(path)

  def RemoveDirectory(self, abs_path):
    if self.platform == 'win32':
      # In other places in chromium, we often have to retry this command
      # because we're worried about other processes still holding on to
      # file handles, but when MB is invoked, it will be early enough in
      # the build that their should be no other processes to interfere.
      # We can change this if need be.
      self.Run(['cmd.exe', '/c', 'rmdir', '/q', '/s', abs_path])
    else:
      shutil.rmtree(abs_path, ignore_errors=True)

  @staticmethod
  def TempDir():
    # This function largely exists so it can be overriden for testing.
    return tempfile.mkdtemp(prefix='mb_')

  @staticmethod
  def TempFile(mode='w'):
    # This function largely exists so it can be overriden for testing.
    return tempfile.NamedTemporaryFile(mode=mode, delete=False)

  def WriteFile(self, path, contents, force_verbose=False):
    # This function largely exists so it can be overriden for testing.
    if self.args.dryrun or self.args.verbose or force_verbose:
      self.Print('\nWriting """\\\n%s""" to %s.\n' % (contents, path))
    with open(path, 'w') as fp:
      return fp.write(contents)


class MBErr(Exception):
  pass


# See http://goo.gl/l5NPDW and http://goo.gl/4Diozm for the painful
# details of this next section, which handles escaping command lines
# so that they can be copied and pasted into a cmd window.
UNSAFE_FOR_SET = set('^<>&|')
UNSAFE_FOR_CMD = UNSAFE_FOR_SET.union(set('()%'))
ALL_META_CHARS = UNSAFE_FOR_CMD.union(set('"'))


def QuoteForSet(arg):
  if any(a in UNSAFE_FOR_SET for a in arg):
    arg = ''.join('^' + a if a in UNSAFE_FOR_SET else a for a in arg)
  return arg


def QuoteForCmd(arg):
  # First, escape the arg so that CommandLineToArgvW will parse it properly.
  if arg == '' or ' ' in arg or '"' in arg:
    quote_re = re.compile(r'(\\*)"')
    arg = '"%s"' % (quote_re.sub(lambda mo: 2 * mo.group(1) + '\\"', arg))

  # Then check to see if the arg contains any metacharacters other than
  # double quotes; if it does, quote everything (including the double
  # quotes) for safety.
  if any(a in UNSAFE_FOR_CMD for a in arg):
    arg = ''.join('^' + a if a in ALL_META_CHARS else a for a in arg)
  return arg


if __name__ == '__main__':
  sys.exit(main(sys.argv[1:]))