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