/*
- * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ * Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file sched.c Paraslash's task and scheduling functions */
+/** \file sched.h Sched and task structures and exported symbols from sched.c. */
/**
- * paraslash's scheduler
+ * Paraslash's scheduler.
*
- * desinged with KISS in mind. It maintains two lists: The pre_select list
- * and the post_select list. Tasks add hokks to these lists by registering
- * themselves to the scheduler.
+ * Designed with KISS in mind. It manages two lists of tasks. The pre_select
+ * list contains pointers to functions that are called before calling select()
+ * from the main loop. Similarly, \a post_select_list is a list of function
+ * pointers each of which is called after the select call. Tasks add hooks to
+ * these lists by registering themselves to the scheduler.
*/
struct sched {
- /** initial value before any pre_select call */
+ /** Initial value before any pre_select call. */
struct timeval default_timeout;
- /** the current timeout for the upcoming select call */
+ /** The current timeout for the upcoming select call. */
struct timeval timeout;
- /** fds that should be watched for readability */
+ /** fds that should be watched for readability. */
fd_set rfds;
- /** fds that should be watched for writability */
+ /** fds that should be watched for writability. */
fd_set wfds;
- /** highest numbered file descriptor in any of the above fd sets */
+ /** Highest numbered file descriptor in any of the above fd sets. */
int max_fileno;
- /** the return value of the previous select call */
- int select_ret;
+ /** In non-NULL, use this function instead of para_select. */
+ int (*select_function)(int, fd_set *, fd_set *, struct timeval *);
};
/**
- * paraslash's task structure
+ * Paraslash's task structure.
*
- * before registering a task to the scheduler, the task structure must be
+ * Before registering a task to the scheduler, the task structure must be
* filled in properly by the caller.
*
- * The pre_select or the post_select pointer, but not both may be NULL. Once
- * a task is registered, its pre_select and post_select function gets called
- * from the scheduler's mainloop. The purpose of the pre_select loop is to add
- * file descriptors to the fd sets of the scheduler and to decrease the select
- * timeout if neccessary. The post_select function may then evaluate these fd
- * sets and act upon the results.
-
- * If one of these functions return a negative value via \a t->ret the
- * (optional) event_handler gets called (it may also be called in case another
- * event happend). In many cases the only possible event is an error or an eof
- * condition and the event handler simply unregisters the task from the
- * scheduler.
+ * If one of these functions sets \a t->error to a negative value, the
+ * task gets unregistered automatically.
*
- * \sa struct sched
+ * \sa struct sched.
*/
struct task {
- /** pointer to the struct this task is embedded in */
- void *private_data;
- /** pre_select hook */
+ /**
+ * The pre select hook of \a t.
+ *
+ * Its purpose is to add file descriptors to the fd sets of the
+ * scheduler and to decrease the select timeout if necessary.
+ */
void (*pre_select)(struct sched *s, struct task *t);
- /** post_select hook */
+ /**
+ * The postselect hook of \a t.
+ *
+ * Evaluate and act upon the results of the previous select call.
+ */
void (*post_select)(struct sched *s, struct task *t);
- /** gets called */
- void (*event_handler)(struct task *t);
- /** pre_select() and post_select store their return value here */
- int ret;
- /** position of the task in the pre_select list of the scheduler */
+ /** Whether this task is in error state. */
+ int error;
+ /** Position of the task in the pre_select list of the scheduler. */
struct list_head pre_select_node;
- /** position of the task in the post_select list of the scheduler */
+ /** Position of the task in the post_select list of the scheduler. */
struct list_head post_select_node;
- /** descriptive text and current status of the task */
+ /** Descriptive text and current status of the task. */
char status[MAXLINE];
};
*/
extern struct timeval *now;
-void *register_task(struct task *t);
-void unregister_task(struct task *t);
-int sched(struct sched *s);
-void init_sched(void);
+void register_task(struct task *t);
+int schedule(struct sched *s);
char *get_task_list(void);
int kill_task(char *id);
+void sched_shutdown(void);