161 lines
6 KiB
C
161 lines
6 KiB
C
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/*---
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This software is copyrighted by the Regents of the University of
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California, and other parties. The following terms apply to all files
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associated with the software unless explicitly disclaimed in
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individual files.
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The authors hereby grant permission to use, copy, modify, distribute,
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and license this software and its documentation for any purpose,
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provided that existing copyright notices are retained in all copies
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and that this notice is included verbatim in any distributions. No
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written agreement, license, or royalty fee is required for any of the
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authorized uses. Modifications to this software may be copyrighted by
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their authors and need not follow the licensing terms described here,
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provided that the new terms are clearly indicated on the first page of
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each file where they apply.
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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
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FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
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DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
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NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
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THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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GOVERNMENT USE: If you are acquiring this software on behalf of the
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U.S. government, the Government shall have only "Restricted Rights" in
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the software and related documentation as defined in the Federal
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Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are
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acquiring the software on behalf of the Department of Defense, the
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software shall be classified as "Commercial Computer Software" and the
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Government shall have only "Restricted Rights" as defined in Clause
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252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the
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authors grant the U.S. Government and others acting in its behalf
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permission to use and distribute the software in accordance with the
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terms specified in this license.
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---*/
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#ifndef _LIBDFA_H
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#define _LIBDFA_H
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#include <libdfa/statemachine.h>
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/*#include "monotree.h"*/
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#include <libdfa/smash.h>
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#include <libdfa/messages.h>
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#include <libdfa/rw.h>
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/**
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Maximum number of concurrent state machines.
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*/
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#define DFA_MACHINE_COUNT 100
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/** TODO: Add transitions and states to dfaSet? */
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typedef struct dfaSet {
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/* MonoTree monoTree; */
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smash_t * smash;
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NetworkSetup networkSetup;
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State * states;
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state_name state_count;
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Transition * transitions;
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state_name transition_count;
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/**
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The locking scheme for libdfa currently works as follows:
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There is a single, per process, read/write lock. When a writer
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(either the main loop, or a worker thread that is deallocating
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its machine) holds the lock, then none of the worker threads may
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make progress. When any reader holds the lock, all worker
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threads obtain an implicit write lock on their statemachine.
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One final note: Since a writer can change the in-memory location
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of state machines, the readers must re-initialize their state
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machine pointer each time they obtain a read lock. This is one
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of the primary barriers to finer grained locking. (See below for
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a straightforward, improved, locking scheme.)
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Performance issues:
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Finer grained locking may be necessary, as all of the
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user-defined callbacks are executed in the main loop while it
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holds the global write lock. A better scheme might work as
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follows:
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Workers obtain a pointer to their state machine, and that
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pointer is immutable over the lifetime of the worker.
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The global write lock is only held when the main loop is
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allocating or deallocating machines; the global read lock is
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only used when the main loop needs to lookup a machine to
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service a request, or when creating new worker threads.
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Each machine has a pthreads_mutex associated with it, and
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worker threads obtain that mutex whenever they access the
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machine. (Therefore user supplied callbacks only would block
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progress on the machine that they are running against.)
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*/
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rwl * lock;
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void * app_setup;
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} DfaSet;
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/**
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Clears DfaSet, and establishes a new empty set of state machines in
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its place. Also zeroes out the callback tables. Does not
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initialize transient state such as network sockets.
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*/
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void dfa_initialize_new(DfaSet * dfaSet, unsigned short port, int count);
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/**
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*/
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int dfa_start (DfaSet *dfaSet,
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Transition transitions[], int transition_count,
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State states[], state_name state_count);
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/**
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Establishes all of the transient state of DfaSet, such as network
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connections and callback tables. Should be called after dfa_initialize_new
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(or, upon recovery, without dfa_initialize_new)
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Returns -1 on error.
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*/
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int dfa_reinitialize (DfaSet *dfaSet, char * localhost,
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Transition transitions[], int transition_count,
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State states[], state_name state_count);
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/**
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Spawns a new thread to handle incoming requests. (There should
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only be one such thread per dfaSet.)
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@see main_loop, which does the same thing, but blocks indefinitely.
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*/
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pthread_t spawn_main_thread(DfaSet * dfaSet);
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/**
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Use the current thread as the worker thread for state machine machine_id. Returns when the machine is freed.
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Should be called after spawn_main_thread (Could be called after main_loop if the application manually manages threads.)
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@return TODO (Not sure what this returns / should return.)
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*/
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void * request(DfaSet * dfaSet, state_name start_state, char * recipient_addr, state_machine_id recipient_machine_id, Message * message);
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/**
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Runs an infinite loop to handle network requests.
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*/
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void* main_loop(DfaSet *dfaSet);
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DfaSet * dfa_malloc(int count, short port,
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char *** broadcast_lists,
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int broadcast_lists_count,
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int * broadcast_list_host_count);
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#endif
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