AppPkg/Applications/Python/Python-2.7.2/Lib/lib2to3/fixes/fix_execfile.py

   1 # Copyright 2006 Google, Inc. All Rights Reserved.
   2 # Licensed to PSF under a Contributor Agreement.
   3
   4 """Fixer for execfile.
   5
   6 This converts usages of the execfile function into calls to the built-in
   7 exec() function.
   8 """
   9
  10 from .. import fixer_base
  11 from ..fixer_util import (Comma, Name, Call, LParen, RParen, Dot, Node,
  12                           ArgList, String, syms)
  13
  14
  15 class FixExecfile(fixer_base.BaseFix):
  16     BM_compatible = True
  17
  18     PATTERN = """
  19     power< 'execfile' trailer< '(' arglist< filename=any [',' globals=any [',' locals=any ] ] > ')' > >
  20     |
  21     power< 'execfile' trailer< '(' filename=any ')' > >
  22     """
  23
  24     def transform(self, node, results):
  25         assert results
  26         filename = results["filename"]
  27         globals = results.get("globals")
  28         locals = results.get("locals")
  29
  30         # Copy over the prefix from the right parentheses end of the execfile
  31         # call.
  32         execfile_paren = node.children[-1].children[-1].clone()
  33         # Construct open().read().
  34         open_args = ArgList([filename.clone()], rparen=execfile_paren)
  35         open_call = Node(syms.power, [Name(u"open"), open_args])
  36         read = [Node(syms.trailer, [Dot(), Name(u'read')]),
  37                 Node(syms.trailer, [LParen(), RParen()])]
  38         open_expr = [open_call] + read
  39         # Wrap the open call in a compile call. This is so the filename will be
  40         # preserved in the execed code.
  41         filename_arg = filename.clone()
  42         filename_arg.prefix = u" "
  43         exec_str = String(u"'exec'", u" ")
  44         compile_args = open_expr + [Comma(), filename_arg, Comma(), exec_str]
  45         compile_call = Call(Name(u"compile"), compile_args, u"")
  46         # Finally, replace the execfile call with an exec call.
  47         args = [compile_call]
  48         if globals is not None:
  49             args.extend([Comma(), globals.clone()])
  50         if locals is not None:
  51             args.extend([Comma(), locals.clone()])
  52         return Call(Name(u"exec"), args, prefix=node.prefix)