ppapi/generators/idl_outfile.py

   1 #!/usr/bin/env python
   2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   3 # Use of this source code is governed by a BSD-style license that can be
   4 # found in the LICENSE file.
   5
   6 """ Output file objects for generator. """
   7
   8 import difflib
   9 import os
  10 import time
  11 import subprocess
  12 import sys
  13
  14 from idl_log import ErrOut, InfoOut, WarnOut
  15 from idl_option import GetOption, Option, ParseOptions
  16 from stat import *
  17
  18 Option('diff', 'Generate a DIFF when saving the file.')
  19
  20
  21 #
  22 # IDLOutFile
  23 #
  24 # IDLOutFile provides a temporary output file.  By default, the object will
  25 # not write the output if the file already exists, and matches what will be
  26 # written.  This prevents the timestamp from changing to optimize cases where
  27 # the output files are used by a timestamp dependent build system
  28 #
  29 class IDLOutFile(object):
  30   def __init__(self, filename, always_write = False, create_dir = True):
  31     self.filename = filename
  32     self.always_write = always_write
  33     self.create_dir = create_dir
  34     self.outlist = []
  35     self.open = True
  36
  37   # Compare the old text to the current list of output lines.
  38   def IsEquivalent_(self, oldtext):
  39     if not oldtext: return False
  40
  41     oldlines = oldtext.split('\n')
  42     curlines = (''.join(self.outlist)).split('\n')
  43
  44     # If number of lines don't match, it's a mismatch
  45     if len(oldlines) != len(curlines):
  46       return False
  47
  48     for index in range(len(oldlines)):
  49       oldline = oldlines[index]
  50       curline = curlines[index]
  51
  52       if oldline == curline: continue
  53
  54       curwords = curline.split()
  55       oldwords = oldline.split()
  56
  57       # Unmatched lines must be the same length
  58       if len(curwords) != len(oldwords):
  59         return False
  60
  61       # If it's not a comment then it's a mismatch
  62       if curwords[0] not in ['*', '/*', '//']:
  63         return False
  64
  65       # Ignore changes to the Copyright year which is autogenerated
  66       # /* Copyright (c) 2011 The Chromium Authors. All rights reserved.
  67       if len(curwords) > 4 and curwords[1] == 'Copyright':
  68         if curwords[4:] == oldwords[4:]: continue
  69
  70       # Ignore changes to auto generation timestamp when line unwrapped
  71       # // From FILENAME.idl modified DAY MON DATE TIME YEAR.
  72       # /* From FILENAME.idl modified DAY MON DATE TIME YEAR. */
  73       if len(curwords) > 8 and curwords[1] == 'From':
  74         if curwords[0:4] == oldwords[0:4]: continue
  75
  76       # Ignore changes to auto generation timestamp when line is wrapped
  77       # * modified DAY MON DATE TIME YEAR.
  78       if len(curwords) > 6 and curwords[1] == 'modified':
  79         continue
  80
  81       return False
  82     return True
  83
  84   # Return the file name
  85   def Filename(self):
  86     return self.filename
  87
  88   # Append to the output if the file is still open
  89   def Write(self, string):
  90     if not self.open:
  91       raise RuntimeError('Could not write to closed file %s.' % self.filename)
  92     self.outlist.append(string)
  93
  94   # Run clang-format on the buffered file contents.
  95   def ClangFormat(self):
  96     clang_format = subprocess.Popen(['clang-format', '-style=Chromium'],
  97                                     stdin=subprocess.PIPE,
  98                                     stdout=subprocess.PIPE)
  99     new_output = clang_format.communicate("".join(self.outlist))[0]
 100     self.outlist = [new_output]
 101
 102   # Close the file, flushing it to disk
 103   def Close(self):
 104     filename = os.path.realpath(self.filename)
 105     self.open = False
 106     outtext = ''.join(self.outlist)
 107     oldtext = ''
 108
 109     if not self.always_write:
 110       if os.path.isfile(filename):
 111         oldtext = open(filename, 'rb').read()
 112         if self.IsEquivalent_(oldtext):
 113           if GetOption('verbose'):
 114             InfoOut.Log('Output %s unchanged.' % self.filename)
 115           return False
 116
 117     if GetOption('diff'):
 118       for line in difflib.unified_diff(oldtext.split('\n'), outtext.split('\n'),
 119                                        'OLD ' + self.filename,
 120                                        'NEW ' + self.filename,
 121                                        n=1, lineterm=''):
 122         ErrOut.Log(line)
 123
 124     try:
 125       # If the directory does not exit, try to create it, if we fail, we
 126       # still get the exception when the file is openned.
 127       basepath, leafname = os.path.split(filename)
 128       if basepath and not os.path.isdir(basepath) and self.create_dir:
 129         InfoOut.Log('Creating directory: %s\n' % basepath)
 130         os.makedirs(basepath)
 131
 132       if not GetOption('test'):
 133         outfile = open(filename, 'wb')
 134         outfile.write(outtext)
 135         outfile.close();
 136         InfoOut.Log('Output %s written.' % self.filename)
 137       return True
 138
 139     except IOError as (errno, strerror):
 140       ErrOut.Log("I/O error(%d): %s" % (errno, strerror))
 141     except:
 142       ErrOut.Log("Unexpected error: %s" % sys.exc_info()[0])
 143       raise
 144
 145     return False
 146
 147
 148 def TestFile(name, stringlist, force, update):
 149   errors = 0
 150
 151   # Get the old timestamp
 152   if os.path.exists(name):
 153     old_time = os.stat(filename)[ST_MTIME]
 154   else:
 155     old_time = 'NONE'
 156
 157   # Create the file and write to it
 158   out = IDLOutFile(filename, force)
 159   for item in stringlist:
 160     out.Write(item)
 161
 162   # We wait for flush to force the timestamp to change
 163   time.sleep(2)
 164
 165   wrote = out.Close()
 166   cur_time = os.stat(filename)[ST_MTIME]
 167   if update:
 168     if not wrote:
 169       ErrOut.Log('Failed to write output %s.' % filename)
 170       return 1
 171     if cur_time == old_time:
 172       ErrOut.Log('Failed to update timestamp for %s.' % filename)
 173       return 1
 174   else:
 175     if wrote:
 176       ErrOut.Log('Should not have writen output %s.' % filename)
 177       return 1
 178     if cur_time != old_time:
 179       ErrOut.Log('Should not have modified timestamp for %s.' % filename)
 180       return 1
 181   return 0
 182
 183
 184 def main():
 185   errors = 0
 186   stringlist = ['Test', 'Testing\n', 'Test']
 187   filename = 'outtest.txt'
 188
 189   # Test forcibly writing a file
 190   errors += TestFile(filename, stringlist, force=True, update=True)
 191
 192   # Test conditionally writing the file skipping
 193   errors += TestFile(filename, stringlist, force=False, update=False)
 194
 195   # Test conditionally writing the file updating
 196   errors += TestFile(filename, stringlist + ['X'], force=False, update=True)
 197
 198   # Clean up file
 199   os.remove(filename)
 200   if not errors: InfoOut.Log('All tests pass.')
 201   return errors
 202
 203
 204 if __name__ == '__main__':
 205   sys.exit(main())