X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=sched.h;h=ada1cc106c068706fc175cc883450c17a237f4b7;hp=9855475d0a7311708306417a77fca071d238ef4c;hb=99708bef7ad12ccb9399186f6055004d11bcf3db;hpb=37db6c718cbd9e350d46703c36dc6860477de476

diff --git a/sched.h b/sched.h
index 9855475d..ada1cc10 100644
--- a/sched.h
+++ b/sched.h
@@ -1,29 +1,86 @@
+/*
+ * Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file sched.h Sched and task structures and exported symbols from sched.c. */
+
+
+/**
+ * Paraslash's scheduler.
+ *
+ * Designed with KISS in mind. It maintains a list of task structures which is
+ * extended when a new task is registered. Each task may define a pre_select
+ * function which is called from the scheduler main loop before it calls
+ * select(). Similarly, each task must define a post_select function which is
+ * called after the select call.
+ */
 struct sched {
-	struct timeval now, timeout;
-	int max_fileno;
-	fd_set rfds, wfds;
-	int select_ret;
+	/** Initial value before any pre_select call. */
 	struct timeval default_timeout;
+	/** The current timeout for the upcoming select call. */
+	struct timeval select_timeout;
+	/** fds that should be watched for readability. */
+	fd_set rfds;
+	/** fds that should be watched for writability. */
+	fd_set wfds;
+	/** Highest numbered file descriptor in any of the above fd sets. */
+	int max_fileno;
+	/** If non-NULL, use this function instead of para_select. */
+	int (*select_function)(int, fd_set *, fd_set *, struct timeval *);
+	/** Tasks which have been registered to the scheduler. */
+	struct list_head task_list;
 };
 
-struct task {
-	void *private_data;
-	unsigned flags;
-	int ret;
-	void (*pre_select)(struct sched *s, struct task *t);
-	void (*post_select)(struct sched *s, struct task *t);
-	void (*event_handler)(struct task *t);
-	struct list_head pre_select_node;
-	struct list_head post_select_node;
-	char status[MAXLINE];
-};
+struct task;
 
-enum task_flags {
-	PRE_ADD_TAIL = 1,
-	POST_ADD_TAIL = 2,
+/** Information that must be supplied by callers of \ref task_register(). */
+struct task_info {
+	/** Used for log messages and by \ref get_task_list(). */
+	const char *name;
+	/**
+	 * The optional pre select method.
+	 *
+	 * 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, void *context);
+	/**
+	 * The mandatory post select method.
+	 *
+	 * Its purpose is to evaluate and act upon the results of the previous
+	 * select call. If this function returns a negative value, the
+	 * scheduler unregisters the task.
+	 */
+	int (*post_select)(struct sched *s, void *context);
+	/**
+	 * This pointer is saved when the task is registered. It is passed to
+	 * ->pre_select() and ->post_select(). Usually this is a pointer to the
+	 * struct owned by the caller which contains the task pointer.
+	 */
+	void *context;
 };
 
-void *register_task(struct task *t);
-void unregister_task(struct task *t);
-int sched(struct sched *s);
-void init_sched(void);
+/**
+ * This is set by the scheduler at the beginning of its main loop.  It may be
+ * used (read-only) from everywhere. As none of the functions called by the
+ * scheduler are allowed to block, this value should be accurate enough so that
+ * there is no need to call clock_gettime() directly.
+ */
+extern const struct timeval *now;
+
+struct task *task_register(struct task_info *info, struct sched *s);
+int schedule(struct sched *s);
+void sched_shutdown(struct sched *s);
+char *get_task_list(struct sched *s);
+void task_notify(struct task *t, int err);
+void task_notify_all(struct sched *s, int err);
+int task_get_notification(const struct task *t);
+int task_status(const struct task *t);
+int task_reap(struct task **tptr);
+void sched_min_delay(struct sched *s);
+void sched_request_timeout(struct timeval *to, struct sched *s);
+void sched_request_timeout_ms(long unsigned ms, struct sched *s);
+int sched_request_barrier(struct timeval *barrier, struct sched *s);
+int sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s);