Update monet.

build/landmines.py

Index: build/landmines.py
diff --git a/build/landmines.py b/build/landmines.py
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+++ b/build/landmines.py
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+#!/usr/bin/env python
+# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""
+This script runs every build as the first hook (See DEPS). If it detects that
+the build should be clobbered, it will delete the contents of the build
+directory.
+
+A landmine is tripped when a builder checks out a different revision, and the
+diff between the new landmines and the old ones is non-null. At this point, the
+build is clobbered.
+"""
+
+import difflib
+import errno
+import logging
+import optparse
+import os
+import shutil
+import sys
+import subprocess
+import time
+
+import landmine_utils
+
+
+SRC_DIR = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+
+
+def get_build_dir(build_tool, is_iphone=False):
+  """
+  Returns output directory absolute path dependent on build and targets.
+  Examples:
+    r'c:\b\build\slave\win\build\src\out'
+    '/mnt/data/b/build/slave/linux/build/src/out'
+    '/b/build/slave/ios_rel_device/build/src/xcodebuild'
+
+  Keep this function in sync with tools/build/scripts/slave/compile.py
+  """
+  ret = None
+  if build_tool == 'xcode':
+    ret = os.path.join(SRC_DIR, 'xcodebuild')
+  elif build_tool in ['make', 'ninja', 'ninja-ios']:  # TODO: Remove ninja-ios.
+    if 'CHROMIUM_OUT_DIR' in os.environ:
+      output_dir = os.environ.get('CHROMIUM_OUT_DIR').strip()
+      if not output_dir:
+        raise Error('CHROMIUM_OUT_DIR environment variable is set but blank!')
+    else:
+      output_dir = landmine_utils.gyp_generator_flags().get('output_dir', 'out')
+    ret = os.path.join(SRC_DIR, output_dir)
+  else:
+    raise NotImplementedError('Unexpected GYP_GENERATORS (%s)' % build_tool)
+  return os.path.abspath(ret)
+
+
+def extract_gn_build_commands(build_ninja_file):
+  """Extracts from a build.ninja the commands to run GN.
+
+  The commands to run GN are the gn rule and build.ninja build step at the
+  top of the build.ninja file. We want to keep these when deleting GN builds
+  since we want to preserve the command-line flags to GN.
+
+  On error, returns the empty string."""
+  result = ""
+  with open(build_ninja_file, 'r') as f:
+    # Read until the second blank line. The first thing GN writes to the file
+    # is the "rule gn" and the second is the section for "build build.ninja",
+    # separated by blank lines.
+    num_blank_lines = 0
+    while num_blank_lines < 2:
+      line = f.readline()
+      if len(line) == 0:
+        return ''  # Unexpected EOF.
+      result += line
+      if line[0] == '\n':
+        num_blank_lines = num_blank_lines + 1
+  return result
+
+def delete_build_dir(build_dir):
+  # GN writes a build.ninja.d file. Note that not all GN builds have args.gn.
+  build_ninja_d_file = os.path.join(build_dir, 'build.ninja.d')
+  if not os.path.exists(build_ninja_d_file):
+    shutil.rmtree(build_dir)
+    return
+
+  # GN builds aren't automatically regenerated when you sync. To avoid
+  # messing with the GN workflow, erase everything but the args file, and
+  # write a dummy build.ninja file that will automatically rerun GN the next
+  # time Ninja is run.
+  build_ninja_file = os.path.join(build_dir, 'build.ninja')
+  build_commands = extract_gn_build_commands(build_ninja_file)
+
+  try:
+    gn_args_file = os.path.join(build_dir, 'args.gn')
+    with open(gn_args_file, 'r') as f:
+      args_contents = f.read()
+  except IOError:
+    args_contents = ''
+
+  shutil.rmtree(build_dir)
+
+  # Put back the args file (if any).
+  os.mkdir(build_dir)
+  if args_contents != '':
+    with open(gn_args_file, 'w') as f:
+      f.write(args_contents)
+
+  # Write the build.ninja file sufficiently to regenerate itself.
+  with open(os.path.join(build_dir, 'build.ninja'), 'w') as f:
+    if build_commands != '':
+      f.write(build_commands)
+    else:
+      # Couldn't parse the build.ninja file, write a default thing.
+      f.write('''rule gn
+command = gn -q gen //out/%s/
+description = Regenerating ninja files
+
+build build.ninja: gn
+generator = 1
+depfile = build.ninja.d
+''' % (os.path.split(build_dir)[1]))
+
+  # Write a .d file for the build which references a nonexistant file. This
+  # will make Ninja always mark the build as dirty.
+  with open(build_ninja_d_file, 'w') as f:
+    f.write('build.ninja: nonexistant_file.gn\n')
+
+
+def clobber_if_necessary(new_landmines):
+  """Does the work of setting, planting, and triggering landmines."""
+  out_dir = get_build_dir(landmine_utils.builder())
+  landmines_path = os.path.normpath(os.path.join(out_dir, '..', '.landmines'))
+  try:
+    os.makedirs(out_dir)
+  except OSError as e:
+    if e.errno == errno.EEXIST:
+      pass
+
+  if os.path.exists(landmines_path):
+    with open(landmines_path, 'r') as f:
+      old_landmines = f.readlines()
+    if old_landmines != new_landmines:
+      old_date = time.ctime(os.stat(landmines_path).st_ctime)
+      diff = difflib.unified_diff(old_landmines, new_landmines,
+          fromfile='old_landmines', tofile='new_landmines',
+          fromfiledate=old_date, tofiledate=time.ctime(), n=0)
+      sys.stdout.write('Clobbering due to:\n')
+      sys.stdout.writelines(diff)
+
+      # Clobber contents of build directory but not directory itself: some
+      # checkouts have the build directory mounted.
+      for f in os.listdir(out_dir):
+        path = os.path.join(out_dir, f)
+        if os.path.isfile(path):
+          os.unlink(path)
+        elif os.path.isdir(path):
+          delete_build_dir(path)
+
+  # Save current set of landmines for next time.
+  with open(landmines_path, 'w') as f:
+    f.writelines(new_landmines)
+
+
+def process_options():
+  """Returns a list of landmine emitting scripts."""
+  parser = optparse.OptionParser()
+  parser.add_option(
+      '-s', '--landmine-scripts', action='append',
+      default=[os.path.join(SRC_DIR, 'build', 'get_landmines.py')],
+      help='Path to the script which emits landmines to stdout. The target '
+           'is passed to this script via option -t. Note that an extra '
+           'script can be specified via an env var EXTRA_LANDMINES_SCRIPT.')
+  parser.add_option('-v', '--verbose', action='store_true',
+      default=('LANDMINES_VERBOSE' in os.environ),
+      help=('Emit some extra debugging information (default off). This option '
+          'is also enabled by the presence of a LANDMINES_VERBOSE environment '
+          'variable.'))
+
+  options, args = parser.parse_args()
+
+  if args:
+    parser.error('Unknown arguments %s' % args)
+
+  logging.basicConfig(
+      level=logging.DEBUG if options.verbose else logging.ERROR)
+
+  extra_script = os.environ.get('EXTRA_LANDMINES_SCRIPT')
+  if extra_script:
+    return options.landmine_scripts + [extra_script]
+  else:
+    return options.landmine_scripts
+
+
+def main():
+  landmine_scripts = process_options()
+
+  if landmine_utils.builder() in ('dump_dependency_json', 'eclipse'):
+    return 0
+
+
+  landmines = []
+  for s in landmine_scripts:
+    proc = subprocess.Popen([sys.executable, s], stdout=subprocess.PIPE)
+    output, _ = proc.communicate()
+    landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
+  clobber_if_necessary(landmines)
+
+  return 0
+
+
+if __name__ == '__main__':
+  sys.exit(main())