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App-dupfind-0.140230-TRIAL
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/ App::dupfind::Threaded::ThreadManagement

NAME

App::dupfind::Threaded::ThreadManagement - Thread management logic, abstracted safely away in its own namespace

VERSION

version 0.140230

DESCRIPTION

Safely tucks away the management of threads and all the threading logic that makes the Map-Reduce feature of App::dupfind possible. Thanks goes out to BrowserUk at perlmonks.org who helped me get this code on the right track.

Please don't use this module by itself. It is for internal use only.

METHODS

clear_counter

The "counter" in App::dupfind::Threaded::ThreadManagment is used to keep track of how many items have been processed by the thread pool. This clear_counter method resets the counter.

counter

The counter itself is a read-only accessor around a thread-shared scalar int

create_thread_pool

Method that spawns N threads to do work for the map-reducer, where N is the number of threads that the user has specified with the "--threads N" flag.

If the user has requested a progress bar, one more thread is spawned which does nothing but monitor overall progress of the thread pool and update the progress bar.

delete_mapped

Deletes a same-size file grouping from the global hashref of same-size file groupings, by key. Thread-safe management of the datastructure is insured.

end_wait_thread_pool

Ends the global work queue, sets the thread terminate flag to 1, and joins the threads in the pool.

increment_counter

Thread-safe way to increment the global shared counter (scalar int value). The counter is key to the successful execution of all threads, and it is imperative that any code executed by the map-reduce engine properly calls increment_counter for work every item it processes.

init_flag

R/W accessor whose read value indicates that the thread pool has been initiated when the return value is true.

mapped

Read-only accessor to the global shared hashref of "work items", i.e.- the groupings of same-size files which are potential duplicates

push_mapped

The thread-safe way to push a new item or items onto a grouping in the global mapped work-item registry. $obj->push_mapped( key => @items );

reset_all

Resets all flags, queues, work mappings, and counters.

In turn, it calls:

  • $self->reset_queue

  • $self->clear_counter

  • $self->reset_mapped

  • $self->init_flag( 0 )

  • $self->term_flag( 0 )

reset_mapped

Destroys the globally-shared mapping of work items. Takes no arguments.

reset_queue

Creates a new Thread::Queue object, which is then accessible via a call to $self->work_queue. This does not end the previous Thread::Queue object. That is the responsibility of $self->end_wait_thread_pool

term_flag

R/W accessor method that indicates to threads that they should exit when a true value is returned.

threads_progress

This method is executed by the single helper thread whose sole responsibility is to update the progress bar for the thread pool, if the user has requested a progress bar

work_queue

Thread-safe shared Thread::Queue object for the current $self object. It can be ended via $self->end_wait_thread_pool and it can thereafter be recreated via $self->reset_queue

The map part of the map-reduce engine pushes work items into this queue.