vss: Use the stripped header also at stream start.

[paraslash.git] / sched.h

diff --git a/sched.h b/sched.h
index 8ed4cd126f73e87cfb2aefc5385856200eedbedd..7158a8732c314b88ad1e162cbb6743c710d01240 100644 (file)
--- a/sched.h
+++ b/sched.h
@@ -1,29 +1,86 @@
+/*
+ * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
+ *
+ * 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 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 {
 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;
        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 *);

 };
 
 };
 

+/**
+ * Paraslash's task structure.
+ *
+ * Before registering a task to the scheduler, the task structure must be
+ * filled in properly by the caller.
+ *
+ * If one of these functions sets \a t->error to a negative value, the
+ * task gets unregistered automatically.
+ *
+ * \sa struct sched.
+ */

 struct task {
 struct task {

-       void *private_data;
-       unsigned flags;
-       int ret;
+       /**
+        * 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);
        void (*pre_select)(struct sched *s, struct task *t);

+       /**
+        * 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);
        void (*post_select)(struct sched *s, struct task *t);

-       void (*error_handler)(struct task *t);
+       /** 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;
        struct list_head pre_select_node;

+       /** Position of the task in the post_select list of the scheduler. */

        struct list_head post_select_node;
        struct list_head post_select_node;

-       char status[MAXLINE];
+       /** Descriptive text and current status of the task. */
+       char status[255];

 };
 
 };
 

-enum task_flags {
-       PRE_ADD_TAIL = 1,
-       POST_ADD_TAIL = 2,
-};
+/**
+ * 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 gettimeofday() directly.
+ */
+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);
+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);
+void sched_request_barrier(struct timeval *barrier, struct sched *s);
+void sched_request_barrier_or_min_delay(struct timeval *barrier, struct sched *s);