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      1 #!/usr/bin/env python
      2 # Copyright (c) 2013 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 import copy
      7 import cStringIO
      8 import optparse
      9 import os
     10 import re
     11 import sys
     12 
     13 
     14 STATEMENT_RE = "\[\[(.*?)\]\]"  # [[...]]
     15 EXPR_RE = "\{\{(.*?)\}\}"  # {{...}}
     16 
     17 def TemplateToPython(template, statement_re, expr_re):
     18   output = cStringIO.StringIO()
     19   indent_re = re.compile(r'\s*')
     20   indent_string = ''
     21   for line in template.splitlines(1):  # 1 => keep line ends
     22     m = statement_re.match(line)
     23     if m:
     24       statement = m.group(1)
     25       indent_string = indent_re.match(statement).group()
     26       if statement.rstrip()[-1:] == ':':
     27         indent_string += '  '
     28       output.write(statement + '\n')
     29     else:
     30       line_ending = ''
     31       while line and line[-1] in '\\"\n\r':
     32         line_ending = line[-1] + line_ending
     33         line = line[:-1]
     34 
     35       m = expr_re.search(line)
     36       if m:
     37         line = line.replace('%', '%%')
     38         subst_line = r'r"""%s""" %% (%s,)' % (
     39             re.sub(expr_re, '%s', line),
     40             ', '.join(re.findall(expr_re, line)))
     41       else:
     42         subst_line = r'r"""%s"""' % line
     43 
     44       out_string = r'%s__outfile__.write(%s + %s)' % (
     45           indent_string,
     46           subst_line,
     47           repr(line_ending))
     48       output.write(out_string + '\n')
     49 
     50   return output.getvalue()
     51 
     52 
     53 def RunTemplate(srcfile, dstfile, template_dict, statement_re=None,
     54                 expr_re=None):
     55   statement_re = statement_re or re.compile(STATEMENT_RE)
     56   expr_re = expr_re or re.compile(EXPR_RE)
     57   script = TemplateToPython(srcfile.read(), statement_re, expr_re)
     58   template_dict = copy.copy(template_dict)
     59   template_dict['__outfile__'] = dstfile
     60   exec script in template_dict
     61 
     62 
     63 def RunTemplateFile(srcpath, dstpath, template_dict, statement_re=None,
     64                     expr_re=None):
     65   with open(srcpath) as srcfile:
     66     with open(dstpath, 'w') as dstfile:
     67       RunTemplate(srcfile, dstfile, template_dict, statement_re, expr_re)
     68 
     69 
     70 def RunTemplateFileIfChanged(srcpath, dstpath, replace):
     71   dststr = cStringIO.StringIO()
     72   with open(srcpath) as srcfile:
     73     RunTemplate(srcfile, dststr, replace)
     74 
     75   if os.path.exists(dstpath):
     76     with open(dstpath) as dstfile:
     77       if dstfile.read() == dststr.getvalue():
     78         return
     79 
     80   with open(dstpath, 'w') as dstfile:
     81     dstfile.write(dststr.getvalue())
     82 
     83 
     84 def RunTemplateString(src, template_dict, statement_re=None, expr_re=None):
     85   srcstr = cStringIO.StringIO(src)
     86   dststr = cStringIO.StringIO()
     87   RunTemplate(srcstr, dststr, template_dict, statement_re, expr_re)
     88   return dststr.getvalue()
     89 
     90 
     91 def main(args):
     92   parser = optparse.OptionParser()
     93   _, args = parser.parse_args(args)
     94   if not args:
     95     return
     96 
     97   with open(args[0]) as f:
     98     print TemplateToPython(
     99         f.read(), re.compile(STATEMENT_RE), re.compile(EXPR_RE))
    100 
    101 if __name__ == '__main__':
    102   sys.exit(main(sys.argv[1:]))
    103