File : adagio-workers.ads
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-- ADAGIO - ADALID - AENEA. --
-- --
-- Copyright (C) 2003 --
-- A. Mosteo. --
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-- Authors: A. Mosteo. (adagio@mosteo.com) --
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-- This program is free software; you can redistribute it and/or modify --
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-- $Id: adagio-workers.ads,v 1.3 2004/01/21 21:05:48 Jano Exp $
-- Workers: tasks which carry a work that may be aborted by external means.
-- Intended for use with blocking calls.
-- Worker pools allow to have families of related tasks.
-- These tasks wait for a new work to be inserted.
-- We choose to make this package generic so all relevant tasks/protected
-- object can be hidden.
-- Unfortunately, this also means that no multi-purpose tasks can be used.
with Generic_event_queue;
with Pragmarc.Assignment;
with Pragmarc.Queue_bounded_blocking;
generic
type Context_type (<>) is private;
with procedure Work_procedure (this : Context_type);
with procedure Abort_procedure (this : Context_type);
Num_workers : Positive;
Max_pending_works : Positive;
package Adagio.Workers is
type Work_type is private;
------------------------------------------------------------------------
-- Start --
------------------------------------------------------------------------
-- Will enqueue a task with given deadline.
-- A standard ATC will be used.
-- Aditionally, on timeout the Abort_procedure will be called.
-- This is useful to abort blocking calls to sockets, for example.
procedure Start (
Data : in Context_type;
Deadline : in Duration;
Started : out Boolean);
------------------------------------------------------------------------
-- Shutdown --
------------------------------------------------------------------------
procedure Shutdown;
private
package Timeout_queue is new
Generic_event_queue (Context_type, Abort_procedure);
type Context_access is access all Context_type;
type Work_type is record
Context : Context_access;
Deadline : Duration;
Timeout : Timeout_queue.Event_type;
end record;
procedure Assign is new Pragmarc.Assignment (Work_type);
package Queue is new
Pragmarc.Queue_bounded_blocking (Work_type, Assign);
task type Worker;
type Worker_pool is array (Integer range <>) of Worker;
end Adagio.Workers;