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       # It wasn't a perfect match. Check for changes we should ignore.
  58       # Unmatched lines must be the same length
  59       if len(curwords) != len(oldwords):
  60         return False
  61
  62       # If it's not a comment then it's a mismatch
  63       if curwords[0] not in ['*', '/*', '//']:
  64         return False
  65
  66       # Ignore changes to the Copyright year which is autogenerated
  67       # /* Copyright (c) 2011 The Chromium Authors. All rights reserved.
  68       if len(curwords) > 4 and curwords[1] == 'Copyright':
  69         if curwords[4:] == oldwords[4:]: continue
  70
  71       # Ignore changes to auto generation timestamp.
  72       # // From FILENAME.idl modified DAY MON DATE TIME YEAR.
  73       # /* From FILENAME.idl modified DAY MON DATE TIME YEAR. */
  74       # The line may be wrapped, so first deal with the first "From" line.
  75       if curwords[1] == 'From':
  76         if curwords[0:4] == oldwords[0:4]: continue
  77
  78       # Ignore changes to auto generation timestamp when line is wrapped
  79       if index > 0:
  80         two_line_oldwords = oldlines[index - 1].split() + oldwords[1:]
  81         two_line_curwords = curlines[index - 1].split() + curwords[1:]
  82         if len(two_line_curwords) > 8 and two_line_curwords[1] == 'From':
  83           if two_line_curwords[0:4] == two_line_oldwords[0:4]: continue
  84
  85       return False
  86     return True
  87
  88   # Return the file name
  89   def Filename(self):
  90     return self.filename
  91
  92   # Append to the output if the file is still open
  93   def Write(self, string):
  94     if not self.open:
  95       raise RuntimeError('Could not write to closed file %s.' % self.filename)
  96     self.outlist.append(string)
  97
  98   # Run clang-format on the buffered file contents.
  99   def ClangFormat(self):
 100     clang_format = subprocess.Popen(['clang-format', '-style=Chromium'],
 101                                     stdin=subprocess.PIPE,
 102                                     stdout=subprocess.PIPE)
 103     new_output = clang_format.communicate("".join(self.outlist))[0]
 104     self.outlist = [new_output]
 105
 106   # Close the file, flushing it to disk
 107   def Close(self):
 108     filename = os.path.realpath(self.filename)
 109     self.open = False
 110     outtext = ''.join(self.outlist)
 111     oldtext = ''
 112
 113     if not self.always_write:
 114       if os.path.isfile(filename):
 115         oldtext = open(filename, 'rb').read()
 116         if self.IsEquivalent_(oldtext):
 117           if GetOption('verbose'):
 118             InfoOut.Log('Output %s unchanged.' % self.filename)
 119           return False
 120
 121     if GetOption('diff'):
 122       for line in difflib.unified_diff(oldtext.split('\n'), outtext.split('\n'),
 123                                        'OLD ' + self.filename,
 124                                        'NEW ' + self.filename,
 125                                        n=1, lineterm=''):
 126         ErrOut.Log(line)
 127
 128     try:
 129       # If the directory does not exit, try to create it, if we fail, we
 130       # still get the exception when the file is openned.
 131       basepath, leafname = os.path.split(filename)
 132       if basepath and not os.path.isdir(basepath) and self.create_dir:
 133         InfoOut.Log('Creating directory: %s\n' % basepath)
 134         os.makedirs(basepath)
 135
 136       if not GetOption('test'):
 137         outfile = open(filename, 'wb')
 138         outfile.write(outtext)
 139         outfile.close();
 140         InfoOut.Log('Output %s written.' % self.filename)
 141       return True
 142
 143     except IOError as (errno, strerror):
 144       ErrOut.Log("I/O error(%d): %s" % (errno, strerror))
 145     except:
 146       ErrOut.Log("Unexpected error: %s" % sys.exc_info()[0])
 147       raise
 148
 149     return False
 150
 151
 152 def TestFile(name, stringlist, force, update):
 153   errors = 0
 154
 155   # Get the old timestamp
 156   if os.path.exists(name):
 157     old_time = os.stat(filename)[ST_MTIME]
 158   else:
 159     old_time = 'NONE'
 160
 161   # Create the file and write to it
 162   out = IDLOutFile(filename, force)
 163   for item in stringlist:
 164     out.Write(item)
 165
 166   # We wait for flush to force the timestamp to change
 167   time.sleep(2)
 168
 169   wrote = out.Close()
 170   cur_time = os.stat(filename)[ST_MTIME]
 171   if update:
 172     if not wrote:
 173       ErrOut.Log('Failed to write output %s.' % filename)
 174       return 1
 175     if cur_time == old_time:
 176       ErrOut.Log('Failed to update timestamp for %s.' % filename)
 177       return 1
 178   else:
 179     if wrote:
 180       ErrOut.Log('Should not have writen output %s.' % filename)
 181       return 1
 182     if cur_time != old_time:
 183       ErrOut.Log('Should not have modified timestamp for %s.' % filename)
 184       return 1
 185   return 0
 186
 187
 188 def main():
 189   errors = 0
 190   stringlist = ['Test', 'Testing\n', 'Test']
 191   filename = 'outtest.txt'
 192
 193   # Test forcibly writing a file
 194   errors += TestFile(filename, stringlist, force=True, update=True)
 195
 196   # Test conditionally writing the file skipping
 197   errors += TestFile(filename, stringlist, force=False, update=False)
 198
 199   # Test conditionally writing the file updating
 200   errors += TestFile(filename, stringlist + ['X'], force=False, update=True)
 201
 202   # Clean up file
 203   os.remove(filename)
 204   if not errors: InfoOut.Log('All tests pass.')
 205   return errors
 206
 207
 208 if __name__ == '__main__':
 209   sys.exit(main())