File Coverage

blib/lib/HTML/Mason/Lexer.pm

Criterion	Covered	Total	%
statement	169	179	94.4
branch	73	88	82.9
condition	21	38	55.2
subroutine	33	33	100.0
pod	4	25	16.0
total	300	363	82.6

# Copyright (c) 1998-2005 by Jonathan Swartz. All rights reserved.
# This program is free software; you can redistribute it and/or modify it
# under the same terms as Perl itself.

package HTML::Mason::Lexer;
$HTML::Mason::Lexer::VERSION = '1.60';
use strict;
use warnings;

use HTML::Mason::Exceptions( abbr => [qw(param_error syntax_error error)] );

use HTML::Mason::Tools qw( taint_is_on );

use Params::Validate qw(:all);
Params::Validate::validation_options( on_fail => sub { param_error join '', @_ } );

use Class::Container;
use base qw(Class::Container);

# This is a block name and what method should be called to lex its
# contents if it is encountered.  'def' & 'method' blocks are special
# cases we actually call ->start again to recursively parse the
# contents of a subcomponent/method.  Theoretically, adding a block is
# as simple as adding an entry to this hash, and possibly a new
# contents lexing methods.
my %blocks = ( args    => 'variable_list_block',
               attr    => 'key_val_block',
               flags   => 'key_val_block',
               cleanup => 'raw_block',
               doc     => 'doc_block',
               filter  => 'raw_block',
               init    => 'raw_block',
               once    => 'raw_block',
               perl    => 'raw_block',
               shared  => 'raw_block',
               text    => 'text_block',
             );

sub block_names
{
    return keys %blocks;
}

sub block_body_method
{
    return $blocks{ $_[1] };
}

{
    my $blocks_re;

    my $re = join '|', __PACKAGE__->block_names;
    $blocks_re = qr/$re/i;

    sub blocks_regex
    {
        return $blocks_re;
    }
}

sub lex
{
    my $self = shift;
    my %p = validate(@_,
                     {comp_source => SCALAR|SCALARREF,
                      name => SCALAR,
                      compiler => {isa => 'HTML::Mason::Compiler'}}
                    );

    # Note - we could improve memory usage here if we didn't make a
    # copy of the scalarref, but that will take some more work to get
    # it working
    $p{comp_source} = ${$p{comp_source}} if ref $p{comp_source};

    # Holds information about the current lex.  Make it local() so
    # we're fully re-entrant.
    local $self->{current} = \%p;
    my $current = $self->{current}; # For convenience

    # Clean up Mac and DOS line endings
    $current->{comp_source} =~ s/\r\n?/\n/g;

    # Initialize lexer state
    $current->{lines} = 1;
    $current->{in_def} = $current->{in_method} = 0;

    # This will be overridden if entering a def or method section.
    $current->{ending} = qr/\G\z/;

    # We need to untaint the component or else the regexes will fail
    # to a Perl bug.  The delete is important because we need to
    # create an entirely new scalar, not just modify the existing one.
    ($current->{comp_source}) = (delete $current->{comp_source}) =~ /(.*)/s
        if taint_is_on;

    eval
    {
        $current->{compiler}->start_component;
        $self->start;
    };
    my $err = $@;
    # Always call end_component, but throw the first error
    eval
    {
        $current->{compiler}->end_component;
    };
    $err ||= $@;

    rethrow_exception $err;
}

sub start
{
    my $self = shift;

    my $end;
    while (1)
    {
        last if $end = $self->match_end;

        $self->match_block && next;

        $self->match_named_block && next;

        $self->match_substitute && next;

        $self->match_comp_call && next;

        $self->match_perl_line && next;

        $self->match_comp_content_call && next;

        $self->match_comp_content_call_end && next;

        $self->match_text && next;

        if ( ( $self->{current}{in_def} || $self->{current}{in_method} ) &&
             $self->{current}{comp_source} =~ /\G\z/ )
        {
            my $type = $self->{current}{in_def} ? 'def' : 'method';
            $self->throw_syntax_error("Missing closing  tag");
        }

        last if $self->{current}{comp_source} =~ /\G\z/;

        # We should never get here - if we do, we're in an infinite loop.
        $self->throw_syntax_error("Infinite parsing loop encountered - Lexer bug?");
    }

    if ( $self->{current}{in_def} || $self->{current}{in_method} )
    {
        my $type = $self->{current}{in_def} ? 'def' : 'method';
        unless ( $end =~ m,\n?,i )
        {
            my $block_name = $self->{current}{"in_$type"};
            $self->throw_syntax_error("No  tag for <%$type $block_name> block");
        }
    }
}

sub match_block
{
    my $self = shift;

    my $blocks_re = $self->blocks_regex;

    if ( $self->{current}{comp_source} =~ /\G<%($blocks_re)>/igcs )
    {
        my $type = lc $1;
        $self->{current}{compiler}->start_block( block_type => $type );

        my $method = $self->block_body_method($type);
        $self->$method( {block_type => $type} );

        return 1;
    }
}

sub generic_block
{
    my ($self, $method, $p) = @_;

    $p->{allow_text} = 1;
    my ($block, $nl) = $self->match_block_end( $p );

    $self->{current}{compiler}->$method( block_type => $p->{block_type},
                                         block => $block );

    $self->{current}{lines} += $block =~ tr/\n//;
    $self->{current}{lines}++ if $nl;

    $self->{current}{compiler}->end_block( block_type => $p->{block_type} );
}

sub text_block
{
    my $self = shift;
    $self->generic_block('text_block', @_);
}

sub raw_block
{
    my $self = shift;
    $self->generic_block('raw_block', @_);
}

sub doc_block
{
    my $self = shift;
    $self->generic_block('doc_block', @_);
}

sub variable_list_block
{
    my ($self, $p) = @_;

    my $ending = qr/ \n | <\/%\Q$p->{block_type}\E> /ix;
    while ( $self->{current}{comp_source} =~ m,
                       \G               # last pos matched
                       (?:
                        [ \t]*
                        ( [\$\@\%] )    # variable type
                        ( [^\W\d]\w* )  # only allows valid Perl variable names
                        [ \t]*
                        # if we have a default arg we'll suck up
                        # any comment it has as part of the default
                        # otherwise explcitly search for a comment
                        (?:
                         (?:              # this entire entire piece is optional
                           =>
                          ( [^\n]+? )     # default value
                         )
                         |
                         (?:              # an optional comment
                          [ \t]*
                          \#
                          [^\n]*
                         )
                        )?
                        (?= $ending )
                        |
                        [ \t]*          # a comment line
                        \#
                        [^\n]*
                        (?= $ending )
                        |
                        [ \t]*          # just space
                       )
                       (\n |          # newline or
                          (?= <\/%\Q$p->{block_type}\E> ) )   # end of block (don't consume it)
                      ,ixgc
          )
    {
        if ( defined $1 && defined $2 && length $1 && length $2 )
        {
            $self->{current}{compiler}->variable_declaration( block_type => $p->{block_type},
                                                              type => $1,
                                                              name => $2,
                                                              default => $3,
                                                            );
        }

        $self->{current}{lines}++ if $4;
    }

    $p->{allow_text} = 0;
    my $nl = $self->match_block_end( $p );
    $self->{current}{lines}++ if $nl;

    $self->{current}{compiler}->end_block( block_type => $p->{block_type} );
}

sub key_val_block
{
    my ($self, $p) = @_;

    my $ending = qr, (?: \n |           # newline or
                         (?= {block_type}\E> ) )   # end of block (don't consume it)
                   ,ix;

    while ( $self->{current}{comp_source} =~ /
                      \G
                      [ \t]*
                      ([\w_]+)          # identifier
                      [ \t]*=>[ \t]*    # separator
                      (\S[^\n]*?)       # value ( must start with a non-space char)
                      $ending
                      |
                      \G\n              # a plain empty line
                      |
                      \G
                      [ \t]*            # an optional comment
                      \#
                      [^\n]*
                      $ending
                      |
                      \G[ \t]+?
                      $ending
                     /xgc )
    {
        if ( defined $1 && defined $2 && length $1 && length $2 )
        {
            $self->{current}{compiler}->key_value_pair( block_type => $p->{block_type},
                                                        key => $1,
                                                        value => $2
                                                      );
        }

        $self->{current}{lines}++;
    }

    $p->{allow_text} = 0;
    my $nl = $self->match_block_end( $p );
    $self->{current}{lines}++ if $nl;

    $self->{current}{compiler}->end_block( block_type => $p->{block_type} );
}

sub match_block_end
{
    my ($self, $p) = @_;

    my $re = $p->{allow_text} ? qr,\G(.*?){block_type}\E>(\n?),is
                              : qr,\G\s*{block_type}\E>(\n?),is;
    if ( $self->{current}{comp_source} =~ /$re/gc )
    {
        return $p->{allow_text} ? ($1, $2) : $1;
    }
    else
    {
        $self->throw_syntax_error("Invalid <%$p->{block_type}> section line");
    }
}

sub match_named_block
{
    my ($self, $p) = @_;

    if ( $self->{current}{comp_source} =~ /\G<%(def|method)(?:\s+([^\n]+?))?\s*>/igcs )
    {
        my ($type, $name) = (lc $1, $2);

        $self->throw_syntax_error("$type block without a name")
            unless defined $name && length $name;

        $self->{current}{compiler}->start_named_block( block_type => $type,
                                                       name => $name );

        # This will cause ->start to return once it hits the
        # appropriate ending tag.
        local $self->{current}{ending} = qr,\G\n?,i;

        local $self->{current}{"in_$type"} = $name;

        $self->start();

        $self->{current}{compiler}->end_named_block( block_type => $type );

        return 1;
    }
}

# Like [a-zA-Z_] but respects locales
my $flag = qr/[[:alpha:]_]\w*/;
sub escape_flag_regex { $flag }

sub match_substitute
{
    # This routine relies on there *not* to be an opening <%foo> tag
    # present, so match_block() must happen first.

    my $self = shift;

    return 0 unless $self->{current}{comp_source} =~ /\G<%/gcs;

    if ( $self->{current}{comp_source} =~
         m{
           \G
           (.+?)                # Substitution body ($1)
           (
            \s*
            (?
            \|                  # A '|'
            \s*
            (                   # (Start $3)
             $flag              # A flag
             (?:\s*,\s*$flag)*  # More flags, with comma separators
            )
            \s*
           )?
           %>                   # Closing tag
          }xcigs )
    {
        $self->{current}{lines} += tr/\n// foreach grep defined, ($1, $2);

        $self->{current}{compiler}->substitution( substitution => $1,
                                                  escape => $3 );
        return 1;
    }
    else
    {
        $self->throw_syntax_error("'<%' without matching '%>'");
    }
}

sub match_comp_call
{
    my $self = shift;

    if ( $self->{current}{comp_source} =~ /\G<&(?!\|)/gcs )
    {
        if ( $self->{current}{comp_source} =~ /\G(.*?)&>/gcs )
        {
            my $call = $1;
            $self->{current}{compiler}->component_call( call => $call );
            $self->{current}{lines} += $call =~ tr/\n//;

            return 1;
        }
        else
        {
            $self->throw_syntax_error("'<&' without matching '&>'");
        }
    }
}


sub match_comp_content_call
{
    my $self = shift;

    if ( $self->{current}{comp_source} =~ /\G<&\|/gcs )
    {
        if ( $self->{current}{comp_source} =~ /\G(.*?)&>/gcs )
        {
            my $call = $1;
            $self->{current}{compiler}->component_content_call( call => $call );
            $self->{current}{lines} += $call =~ tr/\n//;

            return 1;
        }
        else
        {
            $self->throw_syntax_error("'<&|' without matching '&>'");
        }
    }
}

sub match_comp_content_call_end
{
    my $self = shift;

    if ( $self->{current}{comp_source} =~ m,\G,gcs )
    {
        my $call = $1 || '';
        $self->{current}{compiler}->component_content_call_end( call_end => $call );
        $self->{current}{lines} += $call =~ tr/\n//;

        return 1;
    }
}

sub match_perl_line
{
    my $self = shift;

    if ( $self->{current}{comp_source} =~ /\G(?<=^)%([^\n]*)(?:\n|\z)/gcm )
    {
        $self->{current}{compiler}->perl_line( line => $1 );
        $self->{current}{lines}++;

        return 1;
    }
}

sub match_text
{
    my $self = shift;
    my $c = $self->{current};

    # Most of these terminator patterns actually belong to the next
    # lexeme in the source, so we use a lookahead if we don't want to
    # consume them.  We use a lookbehind when we want to consume
    # something in the matched text, like the newline before a '%'.
    if ( $c->{comp_source} =~ m{
                                \G
                                (.*?)         # anything, followed by:
                                (
                                 (?<=\n)(?=%) # an eval line - consume the \n
                                 |
                                 (?=
                                              # - don't consume
                                 |
                                 \\\n         # an escaped newline  - throw away
                                 |
                                 \z           # end of string
                                )
                               }xcgs )
    {
        # Note: to save memory, it might be preferable to break very
        # large $1 strings into several pieces and pass the pieces to
        # compiler->text().  In my testing, this was quite a bit
        # slower, though.  -Ken 2002-09-19
        $c->{compiler}->text( text => $1 ) if length $1;
        # Not checking definedness seems to cause extra lines to be
        # counted with Perl 5.00503.  I'm not sure why - dave
        $c->{lines} += tr/\n// foreach grep defined, ($1, $2);

        return 1;
    }

    return 0;
}

sub match_end
{
    my $self = shift;

    # $self->{current}{ending} is a qr// 'string'.  No need to escape.  It will
    # also include the needed \G marker
    if ( $self->{current}{comp_source} =~ /($self->{current}{ending})/gcs )
    {
        $self->{current}{lines} += $1 =~ tr/\n//;
        return defined $1 && length $1 ? $1 : 1;
    }
    return 0;
}

# goes from current pos, skips a newline if its the next character,
# and then goes to the next newline.  Alternately, the caller can
# provide a starting position.
sub _next_line
{
    my $self = shift;
    my $pos = shift;

    $pos = ( defined $pos ?
             $pos :
             ( substr( $self->{current}{comp_source}, pos($self->{current}{comp_source}), 1 ) eq "\n" ?
               pos($self->{current}{comp_source}) + 1 :
               pos($self->{current}{comp_source}) ) );

    my $to_eol = ( index( $self->{current}{comp_source}, "\n", $pos ) != -1 ?
                   ( index( $self->{current}{comp_source}, "\n" , $pos ) ) - $pos :
                   length $self->{current}{comp_source} );
    return substr( $self->{current}{comp_source}, $pos, $to_eol );
}

sub line_number
{
    my $self = shift;

    return $self->{current}{lines};
}

sub name
{
    my $self = shift;

    return $self->{current}{name};
}

sub throw_syntax_error
{
    my ($self, $error) = @_;

    HTML::Mason::Exception::Syntax->throw( error => $error,
                                           comp_name => $self->name,
                                           source_line => $self->_next_line,
                                           line_number => $self->line_number );
}

1;

__END__