Add --src-dir flag to landmines.py.

build/landmines.py

 #!/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 gyp_environment
 import logging
 import optparse
 import os
 import sys
 import subprocess
 import time
 
 import clobber
 import landmine_utils
 
 
-SRC_DIR = os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
-
-
-def get_build_dir(build_tool, is_iphone=False):
+def get_build_dir(build_tool, src_dir, 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')
+    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)
+    ret = os.path.join(src_dir, output_dir)
   else:
     raise NotImplementedError('Unexpected GYP_GENERATORS (%s)' % build_tool)
   return os.path.abspath(ret)
 
 
-def clobber_if_necessary(new_landmines):
+def clobber_if_necessary(new_landmines, src_dir):
   """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'))
+  out_dir = get_build_dir(landmine_utils.builder(), src_dir)
+  landmines_path = os.path.normpath(os.path.join(src_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.clobber(out_dir)
 
   # 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."""
+  """Returns an options object containing the configuration for this script."""
   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('-d', '--src-dir',
+      help='Path of the source root dir. Overrides the default location of the '
+           'source root dir when calculating the build directory.')
   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)
 
+  if options.src_dir:
+    if not os.path.isdir(options.src_dir):
+      parser.error('Cannot find source root dir at %s' % options.src_dir)
+    logging.debug('Overriding source root dir. Using: %s', options.src_dir)
+  else:
+    options.src_dir = \
+        os.path.dirname(os.path.dirname(os.path.realpath(__file__)))
+
+  if not options.landmine_scripts:
+    options.landmine_scripts = [os.path.join(options.src_dir, 'build',
+                                             'get_landmines.py')]
+
   extra_script = os.environ.get('EXTRA_LANDMINES_SCRIPT')
   if extra_script:
-    return options.landmine_scripts + [extra_script]
-  else:
-    return options.landmine_scripts
+    options.landmine_scripts += [extra_script]
+
+  return options
 
 
 def main():
-  landmine_scripts = process_options()
+  options = process_options()
 
   if landmine_utils.builder() in ('dump_dependency_json', 'eclipse'):
     return 0
 
   gyp_environment.SetEnvironment()
 
   landmines = []
-  for s in landmine_scripts:
+  for s in options.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)
+  clobber_if_necessary(landmines, options.src_dir)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())