1 #

     2 # Copyright (c) 2009 Nokia Corporation and/or its subsidiary(-ies).

     3 # All rights reserved.

     4 # This component and the accompanying materials are made available

     5 # under the terms of "Eclipse Public License v1.0"

     6 # which accompanies this distribution, and is available

     7 # at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 #

     9 # Initial Contributors:

    10 # Nokia Corporation - initial contribution.

    11 #

    12 # Contributors:

    13 #

    14 # Description:

    15 #

    16 #-------------------------------------------------------------------------------

    17 # package: SysDefParser

    18 #

    19 # usage: Wrapper for an XML parser to dispatch callbacks to a client object which

    20 #    analyses the parsed XML data. The auxiliary package SysDefParser::Dispatcher

    21 #    acts as an intermediary between the parser and the client to convert function

    22 #    callbacks to method callbacks using perl's AUTOLOAD mechanism.

    23 #

    24 # public methods:

    25 #

    26 #    new(-client => <client reference>, [-parser => <package name>]) : creates a

    27 #        instance. <client reference> is the instance to which the parser callbacks

    28 #        are dispatched. <package name> is an optional alternative parser client

    29 #        package to use instead of the default XML::Parser class.

    30 #

    31 #    parse(<fileh>): parse the XML data from filehandle <fileh> dispatching

    32 #        callbacks to the client object.

    33 #         

    34 #-------------------------------------------------------------------------------

    35 

    36 package SysDefParser;

    37 use strict;

    38 

    39 sub new

    40 {

    41     my ($class, %args) = @_;

    42     my $self = bless {}, $class;

    43     $self->{client} = delete $args{-client};

    44 

    45     if (exists $args{-parser})

    46     {

    47         $args{Pkg} = 'SysDefParser::Dispatcher';

    48         require $args{-parser};

    49         $self->{parser} = $args{-parser}->createParser(%args);

    50     }

    51     else

    52     {

    53         $self->{parser} = $class->_createParser(%args);

    54     }

    55 

    56     return $self;

    57 }

    58 

    59 sub _createParser

    60 {

    61     my ($class, %args) = @_;

    62     require XML::Parser;

    63     return XML::Parser->new

    64            (

    65                Style        => 'Subs',

    66                Pkg          => 'SysDefParser::Dispatcher',

    67                ErrorContext => 2

    68            );

    69 }

    70 

    71 my $PARSERCLIENT = undef;

    72 

    73 sub _client { return $PARSERCLIENT; }

    74 

    75 sub parse

    76 {

    77     my ($self, $fileh) = @_;

    78 

    79     # we can't pass any context down to the underlying parser so that we can work out which

    80     # object any callbacks from the parser are associated with so, assuming that the parser will

    81     # not be called in a re-entrant fashion, we store the context at this point, so that we can

    82     # then dispatch the callbacks from the parsers 'parse' method to those methods of the saved

    83     # $PARSERCLIENT instance.

    84 

    85     die "Fatal: client object not set\n" if ! defined $self->{client};

    86     die "Fatal: parser client object already set\n" if defined $PARSERCLIENT;

    87     $PARSERCLIENT = $self->{client};

    88 

    89     # call the parser, callbacks will be dispatched to sub AUTOLOAD in SysDefParser::Dispatcher

    90 

    91     my $rv =$self->{parser}->parse($fileh);

    92 

    93     # finished parsing, unset the context

    94 

    95     $PARSERCLIENT = undef;

    96 

    97     return $rv;

    98 }

    99 

   100 #-------------------------------------------------------------------------------

   101 # package SysDefParser::Dispatcher

   102 #

   103 # usage: Internal package. Uses AUTOLOAD mechanism to receive parser callbacks and

   104 #    convert them to object method calls on teh client object.

   105 #

   106 #-------------------------------------------------------------------------------

   107 package SysDefParser::Dispatcher;

   108 use strict;

   109 

   110 sub AUTOLOAD

   111 {

   112     my @ARGS = @_;

   113 

   114     my $client = SysDefParser::_client();

   115 

   116     die "Fatal: parser client object not set\n" if ! defined $client;

   117 

   118     # translate the called back function name to the client method name

   119     my $clientpkg = ref($client);

   120     my $method = $SysDefParser::Dispatcher::AUTOLOAD;

   121 

   122     $method =~ s/^SysDefParser::Dispatcher/$clientpkg/;

   123 

   124     # dispatch the parser's callback to the client object (if implemented by client)

   125     $client->$method(@ARGS) if $client->can($method);

   126 }

   127 

   128 #-------------------------------------------------------------------------------

   129 # -EOF-

   130 #-------------------------------------------------------------------------------

   131 1;