# Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
# Copyright (c) 2009 The Hewlett-Packard Development Company
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met: redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer;
# redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution;
# neither the name of the copyright holders nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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from slicc.ast.StatementAST import StatementAST
from slicc.symbols import Var

class PeekStatementAST(StatementAST):
    def __init__(self, slicc, queue_name, type_ast, statements, method):
        super(PeekStatementAST, self).__init__(slicc)

        self.queue_name = queue_name
        self.type_ast = type_ast
        self.statements = statements
        self.method = method

    def __repr__(self):
        return "[PeekStatementAST: %r queue_name: %r type: %r %r]" % \
               (self.method, self.queue_name, self.type_ast, self.statements)

    def generate(self, code, return_type):
        self.symtab.pushFrame()

        msg_type = self.type_ast.type

        # Add new local var to symbol table
        var = Var(self.symtab, "in_msg", self.location, msg_type, "(*in_msg_ptr)",
                  self.pairs)
        self.symtab.newSymbol(var)

        # Check the queue type
        self.queue_name.assertType("InPort")

        # Declare the new "in_msg_ptr" variable
        mtid = msg_type.ident
        qcode = self.queue_name.var.code
        code('''
{
    const $mtid* in_msg_ptr;
    in_msg_ptr = dynamic_cast<const $mtid *>(($qcode).${{self.method}}());
    assert(in_msg_ptr != NULL);
''')

        # The other statements
        self.statements.generate(code, return_type)
        self.symtab.popFrame()
        code("}")

    def findResources(self, resources):
        self.statements.findResources(resources)