Factor clobber out of build/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 shutil
 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):
   """
   Returns output directory absolute path dependent on build and targets.
   Examples:
@@ skipping 12 matching lines @@
       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)
+      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."""
   parser = optparse.OptionParser()
   parser.add_option(
@@ skipping 36 matching lines @@
     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())