# Copyright 2006 Google, Inc. All Rights Reserved.

# Licensed to PSF under a Contributor Agreement.



"""Fixer for execfile.



This converts usages of the execfile function into calls to the built-in

exec() function.

"""



from .. import fixer_base

from ..fixer_util import (Comma, Name, Call, LParen, RParen, Dot, Node,

                          ArgList, String, syms)





class FixExecfile(fixer_base.BaseFix):



    PATTERN = """

    power< 'execfile' trailer< '(' arglist< filename=any [',' globals=any [',' locals=any ] ] > ')' > >

    |

    power< 'execfile' trailer< '(' filename=any ')' > >

    """



    def transform(self, node, results):

        assert results

        filename = results["filename"]

        globals = results.get("globals")

        locals = results.get("locals")



        # Copy over the prefix from the right parentheses end of the execfile

        # call.

        execfile_paren = node.children[-1].children[-1].clone()

        # Construct open().read().

        open_args = ArgList([filename.clone()], rparen=execfile_paren)

        open_call = Node(syms.power, [Name("open"), open_args])

        read = [Node(syms.trailer, [Dot(), Name('read')]),

                Node(syms.trailer, [LParen(), RParen()])]

        open_expr = [open_call] + read

        # Wrap the open call in a compile call. This is so the filename will be

        # preserved in the execed code.

        filename_arg = filename.clone()

        filename_arg.set_prefix(" ")

        exec_str = String("'exec'", " ")

        compile_args = open_expr + [Comma(), filename_arg, Comma(), exec_str]

        compile_call = Call(Name("compile"), compile_args, "")

        # Finally, replace the execfile call with an exec call.

        args = [compile_call]

        if globals is not None:

            args.extend([Comma(), globals.clone()])

        if locals is not None:

            args.extend([Comma(), locals.clone()])

        return Call(Name("exec"), args, prefix=node.get_prefix())

