Provided by: libmail-box-perl_2.110-1_all 
NAME
Mail::Box::Thread::Manager - maintain threads within a set of folders
INHERITANCE
Mail::Box::Thread::Manager
is a Mail::Reporter
SYNOPSIS
my $mgr = Mail::Box::Manager->new;
my $folder = $mgr->open(folder => '/tmp/inbox');
my $threads = $mgr->threads();
$threads->includeFolder($folder);
my $threads = $msg->threads(folder => $folder);
foreach my $thread ($threads->all) {
$thread->print;
}
$threads->removeFolder($folder);
DESCRIPTION
A (message-)thread is a message with links to messages which followed in reply of that
message. And then the messages with replied to the messages, which replied the original
message. And so on. Some threads are only one message long (never replied to), some
threads are very long.
The "Mail::Box::Thread::Manager" is very powerful. Not only is it able to do a descent
job on MH-like folders (makes a trade-off between perfection and speed), it also can
maintain threads from messages residing in different opened folders. Both facilities are
rare for mail-agents. The manager creates flexible trees with Mail::Box::Thread::Node
objects.
See documentation in the base class.
METHODS
See documentation in the base class.
Constructors
See documentation in the base class.
Mail::Box::Thread::Manager->new(OPTIONS)
A "Mail::Box::Thread::Manager" object is usually created by a Mail::Box::Manager. One
manager can produce more than one of these objects. One thread manager can combine
messages from a set of folders, which may be partially overlapping with other objects
of the same type.
-Option --Defined in --Default
dummy_type Mail::Message::Dummy
folder [ ]
folders [ ]
log Mail::Reporter 'WARNINGS'
thread_body <false>
thread_type Mail::Box::Thread::Node
timespan '3 days'
trace Mail::Reporter 'WARNINGS'
window 10
dummy_type => CLASS
The type of dummy messages. Dummy messages are used to fill holes in detected
threads: referred to by messages found in the folder, but itself not in the folder.
folder => FOLDER | REF-ARRAY-FOLDERS
Specifies which folders are to be covered by the threads. You can specify one or
more open folders. When you close a folder, the manager will automatically remove
the messages of that folder from your threads.
folders => FOLDER | REF-ARRAY-FOLDERS
Equivalent to the "folder" option.
log => LEVEL
thread_body => BOOLEAN
May thread-detection be based on the content of a message? This has a serious
performance implication when there are many messages without "In-Reply-To" and
"References" headers in the folder, because it will cause many messages to be
parsed. NOT IMPLEMENTED YET.
thread_type => CLASS
Type of the thread nodes.
timespan => TIME | 'EVER'
Specify how fast threads usually work: the amount of time between an answer and a
reply. This is used in combination with the "window" option to determine when to
give-up filling the holes in threads.
See Mail::Box::timespan2seconds() for the possibilities for TIME. With 'EVER', the
search for messages in a thread will only be limited by the window-size.
trace => LEVEL
window => INTEGER|'ALL'
The thread-window describes how many messages should be checked at maximum to fill
`holes' in threads for folder which use delay-loading of message headers.
The constant 'ALL' will cause thread-detection not to stop trying to fill holes, but
continue looking until the first message of the folder is reached. Gives the best
quality results, but may perform bad.
example:
use Mail::Box::Manager;
my $mgr = Mail::Box::Manager->new;
my $inbox = $mgr->open(folder => $ENV{MAIL});
my $read = $mgr->open(folder => 'Mail/read');
my $threads = $mgr->threads(folders => [$inbox, $read]);
# longer alternative for last line:
my $threads = $mgr->threads;
$threads->includeFolder($inbox);
$threads->includeFolder($read);
Grouping Folders
$obj->folders()
Returns the folders as managed by this threader.
$obj->includeFolder(FOLDERS)
Add one or more folders to the list of folders whose messages are organized in the
threads maintained by this object. Duplicated inclusions will not cause any problems.
From the folders, the messages which have their header lines parsed (see Mail::Box
about lazy extracting) will be immediately scanned. Messages of which the header is
known only later will have to report this (see toBeThreaded()).
example:
$threads->includeFolder($inbox, $draft);
$obj->removeFolder(FOLDERS)
Remove one or more folders from the list of folders whose messages are organized in
the threads maintained by this object.
example:
$threads->removeFolder($draft);
The Threads
$obj->all()
Returns all messages which start a thread. The list may contain dummy messages and
messages which are scheduled for deletion.
To be able to return all threads, thread construction on each message is performed
first, which may be slow for some folder-types because is will enforce parsing of
message-bodies.
$obj->known()
Returns the list of all messages which are known to be the start of a thread. Threads
containing messages which where not read from their folder (like often happens MH-
folder messages) are not yet known, and hence will not be returned.
The list may contain dummy messages, and messages which are scheduled for deletion.
Threads are detected based on explicitly calling inThread() and thread() with a
messages from the folder.
Be warned that, each time a message's header is read from the folder, the return of
the method can change.
$obj->sortedAll([PREPARE [COMPARE]])
Returns all() the threads by default, but sorted on timestamp.
$obj->sortedKnown([PREPARE [,COMPARE]])
Returns all known() threads, in sorted order. By default, the threads will be sorted
on timestamp, But a different COMPARE method can be specified.
$obj->thread(MESSAGE)
Returns the thread where this MESSAGE is the start of. However, there is a
possibility that this message is a reply itself.
Usually, all messages which are in reply of this message are dated later than the
specified one. All headers of messages later than this one are getting parsed first,
for each folder in this threads-object.
example:
my $threads = $mgr->threads(folder => $inbox);
my $thread = $threads->thread($inbox->message(3));
print $thread->string;
$obj->threadStart(MESSAGE)
Based on a message, and facts from previously detected threads, try to build solid
knowledge about the thread where this message is in.
Internals
$obj->createDummy(MESSAGE-ID)
Get a replacement message to be used in threads. Be warned that a dummy is not a
member of any folder, so the program working with threads must test with
Mail::Message::isDummy() before trying things only available to real messages.
$obj->inThread(MESSAGE)
Collect the thread-information of one message. The `In-Reply-To' and `Reference'
header-fields are processed. If this method is called on a message whose header was
not read yet (as usual for MH-folders, for instance) the reading of that header will
be triggered here.
$obj->outThread(MESSAGE)
Remove the message from the thread-infrastructure. A message is replaced by a dummy.
$obj->toBeThreaded(FOLDER, MESSAGES)
Include the specified messages in/from the threads managed by this object, if this
folder is maintained by this thread-manager.
$obj->toBeUnthreaded(FOLDER, MESSAGES)
Remove the specified messages in/from the threads managed by this object, if this
folder is maintained by this thread-manager.
Error handling
See documentation in the base class.
$obj->AUTOLOAD()
See "Error handling" in Mail::Reporter
$obj->addReport(OBJECT)
See "Error handling" in Mail::Reporter
$obj->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])
Mail::Box::Thread::Manager->defaultTrace([LEVEL]|[LOGLEVEL, TRACELEVEL]|[LEVEL, CALLBACK])
See "Error handling" in Mail::Reporter
$obj->errors()
See "Error handling" in Mail::Reporter
$obj->log([LEVEL [,STRINGS]])
Mail::Box::Thread::Manager->log([LEVEL [,STRINGS]])
See "Error handling" in Mail::Reporter
$obj->logPriority(LEVEL)
Mail::Box::Thread::Manager->logPriority(LEVEL)
See "Error handling" in Mail::Reporter
$obj->logSettings()
See "Error handling" in Mail::Reporter
$obj->notImplemented()
See "Error handling" in Mail::Reporter
$obj->report([LEVEL])
See "Error handling" in Mail::Reporter
$obj->reportAll([LEVEL])
See "Error handling" in Mail::Reporter
$obj->trace([LEVEL])
See "Error handling" in Mail::Reporter
$obj->warnings()
See "Error handling" in Mail::Reporter
Cleanup
See documentation in the base class.
$obj->DESTROY()
See "Cleanup" in Mail::Reporter
DETAILS
This module implements thread-detection on a folder. Messages created by the better
mailers will include "In-Reply-To" and "References" lines, which are used to figure out
how messages are related. If you prefer a better thread detection, they are
implementable, but there may be a serious performance hit (depends on the type of folder
used).
Maintaining threads
A "Mail::Box::Thread::Manager" object is created by the Mail::Box::Manager, using
Mail::Box::Manager::threads(). Each object can monitor the thread-relations between
messages in one or more folders. When more than one folder is specified, the messages are
merged while reading the threads, although nothing changes in the folder-structure.
Adding and removing folders which have to be maintained is permitted at any moment,
although may be quite costly in performance.
An example of the maintained structure is shown below. The Mail::Box::Manager has two
open folders, and a thread-builder which monitors them both. The combined folders have
two threads, the second is two long (msg3 is a reply on msg2). Msg2 is in two folders at
once.
manager
| \
| `----------- threads
| | |
| thread thread---thread
| | /| /
| | // /
+---- folder1 | // /
| | / // /
| `-----msg1 // /
| `-----msg2-'/ /
| / /
`-----folder2 / /
| / /
`-----msg2 /
`-----msg3------'
Delayed thread detection
With all() you get the start-messages of each thread of this folder. When that message
was not found in the folder (not saved or already removed), you get a message of the
dummy-type. These thread descriptions are in perfect state: all messages of the folder
are included somewhere, and each missing message of the threads (holes) are filled by
dummies.
However, to be able to detect all threads it is required to have the headers of all
messages, which is very slow for some types of folders, especially MH and IMAP folders.
For interactive mail-readers, it is preferred to detect threads only on messages which are
in the viewport of the user. This may be sloppy in some situations, but everything is
preferable over reading an MH mailbox with 10k e-mails to read only the see most recent
messages.
In this object, we take special care not to cause unnecessary parsing (loading) of
messages. Threads will only be detected on command, and by default only the message
headers are used.
The following reports the Mail::Box::Thread::Node which is related to a message:
my $thread = $message->thread;
When the message was not put in a thread yet, it is done now. But, more work is done to
return the best thread. Based on various parameters, which where specified when the
folder was created, the method walks through the folder to fill the holes which are in
this thread.
Walking from back to front (recently arrived messages are usually in the back of the
folder), message after message are triggered to be included in their thread. At a certain
moment, the whole thread of the requested method is found, a certain maximum number of
messages was tried, but that didn't help (search window bound reached), or the messages
within the folder are getting too old. Then the search to complete the thread will end,
although more messages of them might have been in the folder: we don't scan the whole
folder for performance reasons.
Finally, for each message where the head is known, for instance for all messages in mbox-
folders, the correct thread is determined immediately. Also, all messages where the head
get loaded later, are automatically included.
DIAGNOSTICS
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.
SEE ALSO
This module is part of Mail-Box distribution version 2.110, built on January 05, 2014.
Website: http://perl.overmeer.net/mailbox/
LICENSE
Copyrights 2001-2014 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://www.perl.com/perl/misc/Artistic.html