=encoding utf8

=head1 NAME

Mail::Box::Parser - reading and writing messages

=head1 INHERITANCE

 Mail::Box::Parser
   is a Mail::Reporter

 Mail::Box::Parser is extended by
   Mail::Box::Parser::C
   Mail::Box::Parser::Lines
   Mail::Box::Parser::Perl

=head1 SYNOPSIS

  # Not instatiatiated itself

=head1 DESCRIPTION

The C<Mail::Box::Parser> manages the parsing of folders.  Usually, you won't
need to know anything about this module, except the options which are
involved with this code.

There are currently three implementations of this module:

=over 4

=item * L<Mail::Box::Parser::C|Mail::Box::Parser::C>

A fast parser written in C<C>.  This package is released as separate
module on CPAN, because the module distribution via CPAN can not
handle XS files which are not located in the root directory of the
module tree.  If a C compiler is available on your system, it will be
used automatically.

=item * L<Mail::Box::Parser::Perl|Mail::Box::Parser::Perl>

A slower parser when the message is in a file, like mbox, which only
uses plain Perl.  This module is a bit slower, and does less checking
and less recovery.

=item * L<Mail::Box::Parser::Lines|Mail::Box::Parser::Lines>

Useful when the message is already in memory.  When you plan to use this
yourself, you probably need to use L<Mail::Message::Construct::Read|Mail::Message::Construct::Read>.

=back

Extends L<"DESCRIPTION" in Mail::Reporter|Mail::Reporter/"DESCRIPTION">.

=head1 METHODS

Extends L<"METHODS" in Mail::Reporter|Mail::Reporter/"METHODS">.

=head2 Constructors

Extends L<"Constructors" in Mail::Reporter|Mail::Reporter/"Constructors">.

=over 4

=item $class-E<gt>B<new>(%options)

Create a parser object which can handle one file.  For
mbox-like mailboxes, this object can be used to read a whole folder.  In
case of MH-like mailboxes, each message is contained in a single file,
so each message has its own parser object.
Improves base, see L<Mail::Reporter/"Constructors">

 -Option           --Default
  fix_header_errors  false
  trusted            false

=over 2

=item fix_header_errors => BOOLEAN

When header errors are detected, the parsing of the header will
be stopped.  Other header lines will become part of the body of
the message.  Set this flag to have the erroneous line added to
the previous header line.

=item trusted => BOOLEAN

Is the input from the file to be trusted, or does it require extra
tests.  Related to L<Mail::Box::new(trusted)|Mail::Box/"Constructors">.

=back

=back

=head2 Attributes

Extends L<"Attributes" in Mail::Reporter|Mail::Reporter/"Attributes">.

=over 4

=item $any-E<gt>B<defaultParserType>( [$class] )

Returns the parser to be used to parse all subsequent
messages, possibly first setting the parser using the optional argument.
Usually, the parser is autodetected; the C<C>-based parser will be used
when it can be, and the Perl-based parser will be used otherwise.

The C<$class> argument allows you to specify a package name to force a
particular parser to be used (such as your own custom parser). You have
to C<use> or C<require> the package yourself before calling this method
with an argument. The parser must be a sub-class of C<Mail::Box::Parser>.

=item $obj-E<gt>B<fixHeaderErrors>( [BOOLEAN] )

If set to C<true>, parsing of a header will not stop on an error, but
attempt to add the erroneous this line to previous field.  Without C<BOOLEAN>,
the current setting is returned.

» example: 

  $folder->parser->fixHeaderErrors(1);
  my $folder = $mgr->open('folder', fix_header_errors => 1);

=item $obj-E<gt>B<trusted>()

Trust the source of the data: do not run additional tests.

=back

=head2 Parsing

=over 4

=item $obj-E<gt>B<bodyAsFile>( $fh [$chars, [$lines]] )

Try to read one message-body from the file, and immediately write
it to the specified file-handle.  Optionally, the predicted number
of CHARacterS and/or C<$lines> to be read can be supplied.  These values may be
C<undef> and may be wrong.

The return is a list of three scalars: the location of the body (begin
and end) and the number of lines in the body.

=item $obj-E<gt>B<bodyAsList>( [$chars, [$lines]] )

Try to read one message-body from the file.  Optionally, the predicted number
of CHARacterS and/or C<$lines> to be read can be supplied.  These values may be
C<undef> and may be wrong.

The return is a list of scalars, each containing one line (including
line terminator), preceded by two integers representing the location
in the file where this body started and ended.

=item $obj-E<gt>B<bodyAsString>( [$chars, [$lines]] )

Try to read one message-body from the file.  Optionally, the predicted number
of CHARacterS and/or C<$lines> to be read can be supplied.  These values may be
C<undef> and may be wrong.

Returned is a list of three scalars: the location in the file
where the body starts, where the body ends, and the string containing the
whole body.

=item $obj-E<gt>B<bodyDelayed>( [$chars, [$lines]] )

Try to read one message-body from the file, but the data is skipped.
Optionally, the predicted number of CHARacterS and/or C<$lines> to be skipped
can be supplied.  These values may be C<undef> and may be wrong.

The return is a list of four scalars: the location of the body (begin and
end), the size of the body, and the number of lines in the body.  The
number of lines may be C<undef>.

=item $obj-E<gt>B<lineSeparator>()

Returns the character or characters which are used to separate lines
in the folder file.  This is based on the first line of the file.
UNIX systems use a single LF to separate lines.  Windows uses a CR and
a LF.  Mac uses CR.

=item $obj-E<gt>B<readHeader>()

Read the whole message-header and return it as list of field-value
pairs.  Mind that some fields will appear more than once.

The first element will represent the position in the file where the
header starts.  The follows the list of header field names and bodies.

» example: 

  my ($where, @header) = $parser->readHeader;

=item $obj-E<gt>B<stop>()

Stop the parser.

=back

=head3 Administering separators

The various "separators" methods are used by L<Mail::Message::Body::Multipart|Mail::Message::Body::Multipart>
to detect parts, and for the file based mailboxes to flag where the new message
starts.

=over 4

=item $obj-E<gt>B<activeSeparator>()

Z<>

=item $obj-E<gt>B<popSeparator>()

Remove the last-pushed separator from the list which is maintained by the
parser.  This will return C<undef> when there is none left.

=item $obj-E<gt>B<pushSeparator>(STRING|Regexp)

Add a boundary line.  Separators tell the parser where to stop reading.
A famous separator is the C<From>-line, which is used in Mbox-like
folders to separate messages.  But also parts (I<attachments>) is a
message are divided by separators.

The specified C<STRING> describes the start of the separator-line.  The
Regexp can specify a more complicated format.

=item $obj-E<gt>B<readSeparator>(%options)

Read the currently active separator (the last one which was pushed).  The
line (or C<undef>) is returned.  Blank-lines before the separator lines
are ignored.

The return are two scalars, where the first gives the location of the
separator in the file, and the second the line which is found as
separator.  A new separator is activated using L<pushSeparator()|Mail::Box::Parser/"Administering separators">.

=item $obj-E<gt>B<resetSeparators>()

Z<>

=item $obj-E<gt>B<separators>()

Z<>

=item $obj-E<gt>B<stripGt>()

Z<>

=back

=head2 Error handling

Extends L<"Error handling" in Mail::Reporter|Mail::Reporter/"Error handling">.

=over 4

=item $obj-E<gt>B<AUTOLOAD>()

Inherited, see L<Mail::Reporter/"Error handling">

=item $obj-E<gt>B<notImplemented>()

Inherited, see L<Mail::Reporter/"Error handling">

=back

=head2 Cleanup

Extends L<"Cleanup" in Mail::Reporter|Mail::Reporter/"Cleanup">.

=over 4

=item $obj-E<gt>B<DESTROY>()

Inherited, see L<Mail::Reporter/"Cleanup">

=back

=head1 DIAGNOSTICS

=over 4

=item Error: class $package does not implement method $method.

Fatal error: the specific C<$package> (or one of its superclasses) does not
implement this method where it should. This message means that some other
related classes do implement this method however the class at hand does
not.  Probably you should investigate this and probably inform the author
of the package.
Cast by C<notImplemented()>

=item Error: parser $type does not extend $pkg.

Cast by C<defaultParserType()>

=item Warning: unexpected end of header in $source: $line

While parsing a message from the specified source (usually a file name),
the parser found a syntax error.  According to the MIME specification in the
RFCs, each header line must either contain a colon, or start with a blank
to indicate a folded field.  Apparently, this header contains a line which
starts on the first position, but not with a field name.

By default, parsing of the header will be stopped.  If there are more header
lines after the erroneous line, they will be added to the body of the message.
In case of L<new(fix_header_errors)|Mail::Box::Parser/"METHODS"> set, the parsing of the header will be continued.
The erroneous line will be added to the preceding field.
Cast by C<readHeader()>

=back

=head1 SEE ALSO

This module is part of Mail-Message version 4.03,
built on January 26, 2026. Website: F<http://perl.overmeer.net/CPAN/>

=head1 LICENSE

For contributors see file ChangeLog.

This software is copyright (c) 2001-2026 by Mark Overmeer.

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.

