Provided by: libmail-box-perl_3.010-2_all bug

NAME

       Mail::Box::File - handle file-based folders

INHERITANCE

        Mail::Box::File
          is a Mail::Box
          is a Mail::Reporter

        Mail::Box::File is extended by
          Mail::Box::Dbx
          Mail::Box::Mbox

SYNOPSIS

DESCRIPTION

       "Mail::Box::File" is the base-class for all file-based folders: folders which bundle
       multiple messages into one single file.  Usually, these messages are separated by a
       special line which indicates the start of the next one.

       Extends "DESCRIPTION" in Mail::Box.

OVERLOADED

       Extends "OVERLOADED" in Mail::Box.

       overload: ""
           Inherited, see "OVERLOADED" in Mail::Box

       overload: @{}
           Inherited, see "OVERLOADED" in Mail::Box

       overload: cmp
           Inherited, see "OVERLOADED" in Mail::Box

METHODS

       Extends "METHODS" in Mail::Box.

   Constructors
       Extends "Constructors" in Mail::Box.

       Mail::Box::File->new(%options)
            -Option           --Defined in     --Default
             access             Mail::Box        'r'
             body_delayed_type  Mail::Box        Mail::Message::Body::Delayed
             body_type                           <see description>
             coerce_options     Mail::Box        []
             create             Mail::Box        <false>
             extract            Mail::Box        10240
             field_type         Mail::Box        undef
             fix_headers        Mail::Box        <false>
             folder             Mail::Box        $ENV{MAIL}
             folderdir          Mail::Box        $ENV{HOME}.'/Mail'
             head_delayed_type  Mail::Box        Mail::Message::Head::Delayed
             head_type          Mail::Box        Mail::Message::Head::Complete
             keep_dups          Mail::Box        <false>
             lock_extension                      '.lock'
             lock_file          Mail::Box        <foldername><lock-extension>
             lock_timeout       Mail::Box        1 hour
             lock_type          Mail::Box        Mail::Box::Locker::DotLock
             lock_wait          Mail::Box        10 seconds
             locker             Mail::Box        undef
             log                Mail::Reporter   'WARNINGS'
             manager            Mail::Box        undef
             message_type       Mail::Box        Mail::Box::File::Message
             multipart_type     Mail::Box        Mail::Message::Body::Multipart
             remove_when_empty  Mail::Box        <true>
             save_on_exit       Mail::Box        <true>
             trace              Mail::Reporter   'WARNINGS'
             trusted            Mail::Box        <depends on folder location>
             write_policy                        undef

           access => MODE
           body_delayed_type => CLASS
           body_type => CLASS|CODE
             The default "body_type" option for "File" folders, which will cause messages larger
             than 10kB to be stored in files and smaller files in memory, is implemented like
             this:

              sub determine_body_type($$)
              {   my $head = shift;
                  my $size = shift || 0;
                  'Mail::Message::Body::'
                     . ($size > 10000 ? 'File' : 'Lines');
              }

           coerce_options => ARRAY
           create => BOOLEAN
           extract => INTEGER | CODE | METHOD | 'LAZY'|'ALWAYS'
           field_type => CLASS
           fix_headers => BOOLEAN
           folder => FOLDERNAME
           folderdir => DIRECTORY
           head_delayed_type => CLASS
           head_type => CLASS
           keep_dups => BOOLEAN
           lock_extension => FILENAME|STRING
             When the dotlock locking mechanism is used, the lock is created with a hardlink to
             the folder file.  For "Mail::Box::File" type of folders, this file is by default
             named as the folder-file itself followed by ".lock".  For example: the "Mail/inbox"
             folder file will have a hardlink made as "Mail/inbox.lock".

             You may specify an absolute filename, a relative (to the folder's directory)
             filename, or an extension (preceded by a dot).  So valid examples are:

              .lock        # appended to the folder's filename
              my_own_lockfile.test   # full filename, same dir
              /etc/passwd            # somewhere else

             When the program runs with less privileges (as normal user), often the default inbox
             folder can not be locked with the lockfile name which is produced by default.

           lock_file => FILENAME
           lock_timeout => SECONDS
           lock_type => CLASS|STRING|ARRAY
           lock_wait => SECONDS
           locker => OBJECT
           log => LEVEL
           manager => MANAGER
           message_type => CLASS
           multipart_type => CLASS
           remove_when_empty => BOOLEAN
           save_on_exit => BOOLEAN
           trace => LEVEL
           trusted => BOOLEAN
           write_policy => 'REPLACE'|'INPLACE'|undef
             Sets the default write policy, as default for a later call to write(policy).  With
             "undef", the best policy is autodetected.

   The folder
       Extends "The folder" in Mail::Box.

       $obj->addMessage($message, %options)
           Inherited, see "The folder" in Mail::Box

       $obj->addMessages(@messages)
           Inherited, see "The folder" in Mail::Box

       Mail::Box::File->appendMessages(%options)
           Appending messages to a file based folder which is not opened is a little risky.  In
           practice, this is often done without locking the folder.  So, another application may
           write to the folder at the same time... :( Hopefully, all goes fast enough that the
           chance on collision is small.

           All %options of Mail::Box::Mbox::new() can be supplied.

            -Option   --Defined in     --Default
             folder     Mail::Box        <required>
             lock_type                   NONE
             message    Mail::Box        undef
             messages   Mail::Box        undef
             share      Mail::Box        <false>

           folder => FOLDERNAME
           lock_type => ...
             See Mail::Box::new(lock_type) for possible values.

           message => MESSAGE
           messages => ARRAY-OF-MESSAGES
           share => BOOLEAN
       $obj->close(%options)
           Inherited, see "The folder" in Mail::Box

       $obj->copyTo($folder, %options)
           Inherited, see "The folder" in Mail::Box

       $obj->delete(%options)
           Inherited, see "The folder" in Mail::Box

       $obj->filename()
           Returns the filename for this folder, which may be an absolute or relative path to the
           file.

           example:

            print $folder->filename;

       $obj->folderdir( [$directory] )
           Inherited, see "The folder" in Mail::Box

       $obj->name()
           Inherited, see "The folder" in Mail::Box

       $obj->organization()
           Inherited, see "The folder" in Mail::Box

       $obj->size()
           Inherited, see "The folder" in Mail::Box

       $obj->type()
           Inherited, see "The folder" in Mail::Box

       $obj->update(%options)
           Inherited, see "The folder" in Mail::Box

       $obj->url()
           Inherited, see "The folder" in Mail::Box

   Folder flags
       Extends "Folder flags" in Mail::Box.

       $obj->access()
           Inherited, see "Folder flags" in Mail::Box

       $obj->isModified()
           Inherited, see "Folder flags" in Mail::Box

       $obj->modified( [BOOLEAN] )
           Inherited, see "Folder flags" in Mail::Box

       $obj->writable()
           Inherited, see "Folder flags" in Mail::Box

   The messages
       Extends "The messages" in Mail::Box.

       $obj->current( [$number|$message|$message_id] )
           Inherited, see "The messages" in Mail::Box

       $obj->find($message_id)
           Inherited, see "The messages" in Mail::Box

       $obj->findFirstLabeled( $label, [BOOLEAN, [$msgs]] )
           Inherited, see "The messages" in Mail::Box

       $obj->message( $index, [$message] )
           Inherited, see "The messages" in Mail::Box

       $obj->messageId( $message_id, [$message] )
           Inherited, see "The messages" in Mail::Box

       $obj->messageIds()
           Inherited, see "The messages" in Mail::Box

       $obj->messages( <'ALL'|$range|'ACTIVE'|'DELETED'|$label| !$label|$filter> )
           Inherited, see "The messages" in Mail::Box

       $obj->nrMessages(%options)
           Inherited, see "The messages" in Mail::Box

       $obj->scanForMessages($message, $message_ids, $timespan, $window)
           Inherited, see "The messages" in Mail::Box

   Sub-folders
       Extends "Sub-folders" in Mail::Box.

       $obj->listSubFolders(%options)
       Mail::Box::File->listSubFolders(%options)
           Inherited, see "Sub-folders" in Mail::Box

       $obj->nameOfSubFolder( $subname, [$parentname] )
       Mail::Box::File->nameOfSubFolder( $subname, [$parentname] )
           Inherited, see "Sub-folders" in Mail::Box

       $obj->openRelatedFolder(%options)
           Inherited, see "Sub-folders" in Mail::Box

       $obj->openSubFolder($subname, %options)
           Inherited, see "Sub-folders" in Mail::Box

       $obj->topFolderWithMessages()
       Mail::Box::File->topFolderWithMessages()
           Inherited, see "Sub-folders" in Mail::Box

   Internals
       Extends "Internals" in Mail::Box.

       $obj->coerce($message, %options)
           Inherited, see "Internals" in Mail::Box

       $obj->create($foldername, %options)
       Mail::Box::File->create($foldername, %options)
            -Option   --Defined in--Default
             folderdir  Mail::Box   undef

           folderdir => DIRECTORY
       $obj->determineBodyType($message, $head)
           Inherited, see "Internals" in Mail::Box

       $obj->folderToFilename( $foldername, $folderdir, [$subext] )
       Mail::Box::File->folderToFilename( $foldername, $folderdir, [$subext] )
           Translate a folder name into a filename, using the $folderdir value to replace a
           leading "=".  $subext is only used for MBOX folders.

       Mail::Box::File->foundIn( [$foldername], %options )
           Inherited, see "Internals" in Mail::Box

       $obj->lineSeparator( [<STRING|'CR'|'LF'|'CRLF'>] )
           Inherited, see "Internals" in Mail::Box

       $obj->locker()
           Inherited, see "Internals" in Mail::Box

       $obj->messageCreateOptions( [$type, $config] )
           Returns a key-value list of options to be used each time a new message is read from a
           file.  The list is preceded by the $type of message which has to be created.

           This data is used by readMessages() and updateMessages().  With $type and $config, a
           new configuration is set.

       $obj->moveAwaySubFolder($directory, $extension)
           The $directory is renamed by appending the $extension, which defaults to ".d", to make
           place for a folder file on that specific location.  "false" is returned if this
           failed.

       $obj->parser()
           Create a parser for this mailbox.  The parser stays alive as long as the folder is
           open.

       $obj->read(%options)
           Inherited, see "Internals" in Mail::Box

       $obj->readMessages(%options)
           Inherited, see "Internals" in Mail::Box

       $obj->storeMessage($message)
           Inherited, see "Internals" in Mail::Box

       $obj->toBeThreaded($messages)
           Inherited, see "Internals" in Mail::Box

       $obj->toBeUnthreaded($messages)
           Inherited, see "Internals" in Mail::Box

       $obj->updateMessages(%options)
           For file based folders, the file handle stays open until the folder is closed.  Update
           is therefore rather simple: move to the end of the last known message, and continue
           reading...

       $obj->write(%options)
            -Option      --Defined in     --Default
             force         Mail::Box        <false>
             policy                         undef
             save_deleted  Mail::Box        <false>

           force => BOOLEAN
           policy => 'REPLACE'|'INPLACE'|undef
             In what way will the mail folder be updated.  If not specified during the write, the
             value of the new(write_policy) at folder creation is taken.

             Valid values:

             •   "REPLACE"

                 First a new folder is written in the same directory as the folder which has to
                 be updated, and then a call to move will throw away the old immediately
                 replacing it by the new.

                 Writing in "REPLACE" module is slightly optimized: messages which are not
                 modified are copied from file to file, byte by byte.  This is much faster than
                 printing the data which is will be done for modified messages.

             •   "INPLACE"

                 The original folder file will be opened read/write.  All message which where not
                 changed will be left untouched, until the first deleted or modified message is
                 detected.  All further messages are printed again.

             •   "undef"

                 As default, or when "undef" is explicitly specified, first "REPLACE" mode is
                 tried.  Only when that fails, an "INPLACE" update is performed.

             "INPLACE" will be much faster than "REPLACE" when applied on large folders, however
             requires the "truncate" function to be implemented on your operating system (at
             least available for recent versions of Linux, Solaris, Tru64, HPUX).  It is also
             dangerous: when the program is interrupted during the update process, the folder is
             corrupted.  Data may be lost.

             However, in some cases it is not possible to write the folder with "REPLACE".  For
             instance, the usual incoming mail folder on UNIX is stored in a directory where a
             user can not write.  Of course, the "root" and "mail" users can, but if you want to
             use this Perl module with permission of a normal user, you can only get it to work
             in "INPLACE" mode.  Be warned that in this case folder locking via a lockfile is not
             possible as well.

           save_deleted => BOOLEAN
       $obj->writeMessages(%options)
           Inherited, see "Internals" in Mail::Box

   Other methods
       Extends "Other methods" in Mail::Box.

       $obj->timespan2seconds($time)
       Mail::Box::File->timespan2seconds($time)
           Inherited, see "Other methods" in Mail::Box

   Error handling
       Extends "Error handling" in Mail::Box.

       $obj->AUTOLOAD()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->addReport($object)
           Inherited, see "Error handling" in Mail::Reporter

       $obj->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
       Mail::Box::File->defaultTrace( [$level]|[$loglevel, $tracelevel]|[$level, $callback] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->errors()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->log( [$level, [$strings]] )
       Mail::Box::File->log( [$level, [$strings]] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->logPriority($level)
       Mail::Box::File->logPriority($level)
           Inherited, see "Error handling" in Mail::Reporter

       $obj->logSettings()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->notImplemented()
           Inherited, see "Error handling" in Mail::Reporter

       $obj->report( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->reportAll( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->trace( [$level] )
           Inherited, see "Error handling" in Mail::Reporter

       $obj->warnings()
           Inherited, see "Error handling" in Mail::Reporter

   Cleanup
       Extends "Cleanup" in Mail::Box.

       $obj->DESTROY()
           Inherited, see "Cleanup" in Mail::Box

   DETAILS
       File based folders

       File based folders maintain a folder (a set of messages) in one single file.  The
       advantage is that your folder has only one single name, which speeds-up access to all
       messages at once.

       The disadvantage over directory based folder (see Mail::Box::Dir) is that you have to
       construct some means to keep all message apart, for instance by adding a message
       separator, and this will cause problems.  Where access to all messages at once is faster
       in file based folders, access to a single message is (much) slower, because the whole
       folder must be read.

DETAILS

       Extends "DETAILS" in Mail::Box.

DIAGNOSTICS

       Error: Cannot append messages to folder file $filename: $!
           Appending messages to a not-opened file-organized folder may fail when the operating
           system does not allow write access to the file at hand.

       Error: Cannot create directory $dir for folder $name.
           While creating a file-organized folder, at most one level of directories is created
           above it.  Apparently, more levels of directories are needed, or the operating system
           does not allow you to create the directory.

       Error: Cannot create folder file $name: $!
           The file-organized folder file cannot be created for the indicated reason.  In common
           cases, the operating system does not grant you write access to the directory where the
           folder file should be stored.

       Error: Cannot get a lock on $type folder $self.
           A lock is required to get access to the folder.  If no locking is needed, specify the
           NONE lock type.

       Error: Cannot move away sub-folder $dir
       Warning: Cannot remove folder $name file $filename: $!
           Writing an empty folder will usually cause that folder to be removed, which fails for
           the indicated reason.  new(remove_when_empty)

       Warning: Cannot remove folder $name file $filename: $!
           Writing an empty folder will usually cause that folder to be removed, which fails for
           the indicated reason.  new(remove_when_empty) controls whether the empty folder will
           removed; setting it to false (0) may be needed to avoid this message.

       Error: Cannot replace $filename by $tempname, to update folder $name: $!
           The replace policy wrote a new folder file to update the existing, but was unable to
           give the final touch: replacing the old version of the folder file for the indicated
           reason.

       Warning: Changes not written to read-only folder $self.
           You have opened the folder read-only --which is the default set by new(access)--, made
           modifications, and now want to close it.  Set close(force) if you want to overrule the
           access mode, or close the folder with close(write) set to "NEVER".

       Error: Copying failed for one message.
           For some reason, for instance disc full, removed by external process, or read-
           protection, it is impossible to copy one of the messages.  Copying will proceed for
           the other messages.

       Error: Destination folder $name is not writable.
           The folder where the messages are copied to is not opened with write access (see
           new(access)).  This has no relation with write permission to the folder which is
           controlled by your operating system.

       Warning: Different messages with id $msgid
           The message id is discovered more than once within the same folder, but the content of
           the message seems to be different.  This should not be possible: each message must be
           unique.

       Error: File too short to get write message $nr ($size, $need)
           Mail::Box is lazy: it tries to leave messages in the folders until they are used,
           which saves time and memory usage.  When this message appears, something is terribly
           wrong: some lazy message are needed for updating the folder, but they cannot be
           retrieved from the original file anymore.  In this case, messages can be lost.

           This message does appear regularly on Windows systems when using the 'replace' write
           policy.  Please help to find the cause, probably something to do with Windows
           incorrectly handling multiple filehandles open in the same file.

       Warning: Folder $name file $filename is write-protected.
           The folder is opened writable or for appending via new(access), but the operating
           system does not permit writing to the file.  The folder will be opened read-only.

       Error: Folder $name not deleted: not writable.
           The folder must be opened with write access via new(access), otherwise removing it
           will be refused.  So, you may have write-access according to the operating system, but
           that will not automatically mean that this "delete" method permits you to.  The
           reverse remark is valid as well.

       Error: Invalid timespan '$timespan' specified.
           The string does not follow the strict rules of the time span syntax which is permitted
           as parameter.

       Warning: Message-id '$msgid' does not contain a domain.
           According to the RFCs, message-ids need to contain a unique random part, then an "@",
           and then a domain name.  This is made to avoid the creation of two messages with the
           same id.  The warning emerges when the "@" is missing from the string.

       Error: Package $package does not implement $method.
           Fatal error: the specific 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.

       Error: Unable to create subfolder $name of $folder.
           The copy includes the subfolders, but for some reason it was not possible to copy one
           of these.  Copying will proceed for all other sub-folders.

       Error: Unable to update folder $self.
           When a folder is to be written, both replace and inplace write policies are tried,  If
           both fail, the whole update fails.  You may see other, related, error messages to
           indicate the real problem.

SEE ALSO

       This module is part of Mail-Box distribution version 3.010, built on July 18, 2023.
       Website: http://perl.overmeer.net/CPAN/

LICENSE

       Copyrights 2001-2023 by [Mark Overmeer]. For other contributors see ChangeLog.

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.  See http://dev.perl.org/licenses/