Mail::Mbox::MessageParser::Cache - A cache-based mbox folder reader

       David Coppit <david@coppit.org>.

       No known bugs.

       Contact david@coppit.org for bug reports and suggestions.

       This module implements a cached-based mbox folder reader. It can only be used when cache information
       already exists. Users must not instantiate this class directly--use Mail::Mbox::MessageParser instead.
       The base MessageParser module will automatically manage the use of cache and non-cache implementations.

   METHODSANDFUNCTIONS
       The following methods and functions are specific to the Mail::Mbox::MessageParser::Cache package. For
       additional inherited ones, see the Mail::Mbox::MessageParser documentation.

       $ref = new( { 'file_name' => <mailbox file name>, 'file_handle' => <mailbox file handle>, });
               <file_name> - The full filename of the mailbox
               <file_handle> - An opened file handle for the mailbox

           The  constructor  for  the class takes two parameters. file_name is the filename of the mailbox. This
           will be used as the cache key, so it's important that it fully defines the path to the  mailbox.  The
           file_handle argument is the opened file handle to the mailbox. Both arguments are required.

           Returns a reference to a Mail::Mbox::MessageParser object, or a string describing the error.

       reset()read_next_email()
           These methods are overridden in this subclass of Mail::Mbox::MessageParser.

       This code was originally part of the grepmail  distribution.  See  http://grepmail.sf.net/  for  previous
       versions of grepmail which included early versions of this code.

       This  code  is distributed under the GNU General Public License (GPL) Version 2.  See the file LICENSE in
       the distribution for details.

       Mail::Mbox::MessageParser::Cache - A cache-based mbox folder reader

       Mail::Mbox::MessageParser

perl v5.36.0                                       2023-08-06              Mail::Mbox::MessageParser::Cache(3pm)

         #!/usr/bin/perl

         use Mail::Mbox::MessageParser;

         my $filename = 'mail/saved-mail';
         my $filehandle = new FileHandle($filename);

         # Set up cache
         Mail::Mbox::MessageParser::SETUP_CACHE(
           { 'file_name' => '/tmp/cache' } );

         my $folder_reader =
           new Mail::Mbox::MessageParser( {
             'file_name' => $filename,
             'file_handle' => $filehandle,
             'enable_cache' => 1,
           } );

         die $folder_reader unless ref $folder_reader;

         warn "No cached information"
           if $Mail::Mbox::MessageParser::Cache::UPDATING_CACHE;

         # Any newlines or such before the start of the first email
         my $prologue = $folder_reader->prologue;
         print $prologue;

         # This is the main loop. It's executed once for each email
         while(!$folder_reader->end_of_file());
         {
           my $email = $folder_reader->read_next_email();
           print $email;
         }