Make mp3_seek_next_header() more readable.

[paraslash.git] / sched.c

diff --git a/sched.c b/sched.c
index a7660f5972c9f678b6f3a19b7b4398a1e43ae24b..4df32fa1b16aa388eb46683bdd307c2a127c070c 100644 (file)
--- a/sched.c
+++ b/sched.c
@@ -1,10 +1,10 @@
 /*
 /*

- * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>

  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 

-/** \file sched.c paraslash's scheduling functions */
+/** \file sched.c Paraslash's scheduling functions. */

 
 #include <dirent.h> /* readdir() */
 #include <assert.h>
 
 #include <dirent.h> /* readdir() */
 #include <assert.h>


@@ -24,19 +24,46 @@ static int initialized;
 static struct timeval now_struct;
 struct timeval *now = &now_struct;
 
 static struct timeval now_struct;
 struct timeval *now = &now_struct;
 

+/**
+ * Remove a task from the scheduler.
+ *
+ * \param t The task to remove.
+ *
+ * If the pre_select pointer of \a t is not \p NULL, it is removed from
+ * the pre_select list of the scheduler. Same goes for \a post_select.
+ */
+static void unregister_task(struct task *t)
+{
+       if (!initialized)
+               return;
+       PARA_INFO_LOG("unregistering %s (%s)\n", t->status,
+               t->error <0? para_strerror(-t->error) : "shutdown");
+       if (t->pre_select)
+               list_del(&t->pre_select_node);
+       if (t->post_select)
+               list_del(&t->post_select_node);
+       t->error = -E_TASK_UNREGISTERED;
+};
+
+

 static void sched_preselect(struct sched *s)
 {
        struct task *t, *tmp;
 static void sched_preselect(struct sched *s)
 {
        struct task *t, *tmp;

-again:

        list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {
        list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node) {

-               t->pre_select(s, t);
+               if (t->error >= 0)
+                       t->pre_select(s, t);

 //             PARA_INFO_LOG("%s \n", t->status);
 //             PARA_INFO_LOG("%s \n", t->status);

-               if (t->ret > 0)
+               if (t->error >= 0)

                        continue;
                        continue;

-               if (!t->event_handler)
-                       continue;
-               t->event_handler(t);
-               goto again;
+               /*
+                * We have to check whether the list is empty because the call
+                * to ->pre_select() might have called sched_shutdown(). In
+                * this case t has been unregistered already, so we must not
+                * unregister it again.
+                */
+               if (list_empty(&pre_select_list))
+                       return;
+               unregister_task(t);

        }
 }
 
        }
 }
 


@@ -45,18 +72,22 @@ static void sched_post_select(struct sched *s)
        struct task *t, *tmp;
 
        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
        struct task *t, *tmp;
 
        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {

-               t->post_select(s, t);
+               if (t->error >= 0)
+                       t->post_select(s, t);

 //             PARA_INFO_LOG("%s: %d\n", t->status, t->ret);
 //             PARA_INFO_LOG("%s: %d\n", t->status, t->ret);

-               if (t->ret > 0 || !t->event_handler)
+               if (t->error >= 0)

                        continue;
                        continue;

-               t->event_handler(t);
+               /* nec., see sched_preselect() */
+               if (list_empty(&post_select_list))
+                       return;
+               unregister_task(t);

        }
 }
 
 /**
        }
 }
 
 /**

- * the core function for all paraslash programs
+ * The core function for all paraslash programs.

  *
  *

- * \param s pointer to the scheduler struct
+ * \param s Pointer to the scheduler struct.

  *
  * This function updates the global \a now pointer, calls all registered
  * pre_select hooks which may set the timeout and add any file descriptors to
  *
  * This function updates the global \a now pointer, calls all registered
  * pre_select hooks which may set the timeout and add any file descriptors to


@@ -68,10 +99,14 @@ static void sched_post_select(struct sched *s)
  *
  * \sa task, now.
  */
  *
  * \sa task, now.
  */

-int sched(struct sched *s)
+int schedule(struct sched *s)

 {
 {

+       int ret;
+

        if (!initialized)
                return -E_NOT_INITIALIZED;
        if (!initialized)
                return -E_NOT_INITIALIZED;

+       if (!s->select_function)
+               s->select_function = para_select;

        gettimeofday(now, NULL);
 again:
        FD_ZERO(&s->rfds);
        gettimeofday(now, NULL);
 again:
        FD_ZERO(&s->rfds);


@@ -79,10 +114,11 @@ again:
        s->timeout = s->default_timeout;
        s->max_fileno = -1;
        sched_preselect(s);
        s->timeout = s->default_timeout;
        s->max_fileno = -1;
        sched_preselect(s);

-       s->select_ret = para_select(s->max_fileno + 1, &s->rfds,
-               &s->wfds, &s->timeout);
-       if (s->select_ret < 0)
-               return s->select_ret;
+       if (list_empty(&pre_select_list) && list_empty(&post_select_list))
+               return 0;
+       ret = s->select_function(s->max_fileno + 1, &s->rfds, &s->wfds, &s->timeout);
+       if (ret < 0)
+               return ret;

        gettimeofday(now, NULL);
        sched_post_select(s);
        if (list_empty(&pre_select_list) && list_empty(&post_select_list))
        gettimeofday(now, NULL);
        sched_post_select(s);
        if (list_empty(&pre_select_list) && list_empty(&post_select_list))


@@ -91,18 +127,18 @@ again:
 }
 
 /**
 }
 
 /**

- * initialize the paraslash scheduler
+ * Initialize the paraslash scheduler.

  */
 static void init_sched(void)
 {
  */
 static void init_sched(void)
 {

-       PARA_INFO_LOG("%s", "initializing scheduler\n");
+       PARA_INFO_LOG("initializing scheduler\n");

        INIT_LIST_HEAD(&pre_select_list);
        INIT_LIST_HEAD(&post_select_list);
        initialized = 1;
 };
 
 /**
        INIT_LIST_HEAD(&pre_select_list);
        INIT_LIST_HEAD(&post_select_list);
        initialized = 1;
 };
 
 /**

- * add a task to the scheduler
+ * Add a task to the scheduler.

  *
  * \param t the task to add
  *
  *
  * \param t the task to add
  *


@@ -118,37 +154,18 @@ void register_task(struct task *t)
        PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
        if (t->pre_select) {
                PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);
        PARA_INFO_LOG("registering %s (%p)\n", t->status, t);
        if (t->pre_select) {
                PARA_DEBUG_LOG("pre_select: %p\n", &t->pre_select);

-               para_list_add(&t->pre_select_node, &pre_select_list);
+               list_add_tail(&t->pre_select_node, &pre_select_list);

        }
        if (t->post_select) {
                PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);
        }
        if (t->post_select) {
                PARA_DEBUG_LOG("post_select: %p\n", &t->pre_select);

-               para_list_add(&t->post_select_node, &post_select_list);
+               list_add_tail(&t->post_select_node, &post_select_list);

        }
 }
 
 /**
        }
 }
 
 /**

- * remove a task from the scheduler
- *
- * \param t the task to remove
- *
- * If the pre_select pointer of \a t is not \p NULL, it is removed from
- * the pre_select list of the scheduler. Same goes for \a post_select.
- */
-void unregister_task(struct task *t)
-{
-       if (!initialized)
-               return;
-       PARA_INFO_LOG("unregistering %s (%p)\n", t->status, t);
-       if (t->pre_select)
-               list_del(&t->pre_select_node);
-       if (t->post_select)
-               list_del(&t->post_select_node);
-};
-
-/**
- * unregister all tasks
+ * Unregister all tasks.

  *
  *

- * This will cause \a sched() to return immediately because both the
+ * This will cause \a schedule() to return immediately because both the

  * \a pre_select_list and the \a post_select_list are empty.
  */
 void sched_shutdown(void)
  * \a pre_select_list and the \a post_select_list are empty.
  */
 void sched_shutdown(void)


@@ -159,16 +176,15 @@ void sched_shutdown(void)
                return;
        list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
                unregister_task(t);
                return;
        list_for_each_entry_safe(t, tmp, &pre_select_list, pre_select_node)
                unregister_task(t);

-       /* remove tasks which do not have a pre_select hook */

        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
                unregister_task(t);
        initialized = 0;
 };
 
 /**
        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node)
                unregister_task(t);
        initialized = 0;
 };
 
 /**

- * get the list of all registered tasks.
+ * Get the list of all registered tasks.

  *
  *

- * \return the task list
+ * \return The task list.

  *
  * Each entry of the list contains an identifier which is simply a hex number
  * that may be used in \a kill_task() to terminate the task.
  *
  * Each entry of the list contains an identifier which is simply a hex number
  * that may be used in \a kill_task() to terminate the task.


@@ -200,12 +216,12 @@ char *get_task_list(void)
 }
 
 /**
 }
 
 /**

- * simulate an error for the given task
+ * Simulate an error for the given task.

  *
  *

- * \param id the task identifier
+ * \param id The task identifier.

  *
  *

- * Find the task identified by \a id, set the tasks' return value to
- * \p -E_TASK_KILLED and call the event handler of the task.
+ * Find the task identified by \a id, set the tasks' error value to
+ * \p -E_TASK_KILLED and unregister the task.

  *
  * \return Positive on success, negative on errors (e.g. if \a id does not
  * correspond to a registered task).
  *
  * \return Positive on success, negative on errors (e.g. if \a id does not
  * correspond to a registered task).


@@ -221,18 +237,14 @@ int kill_task(char *id)
                sprintf(buf, "%p", t);
                if (strcmp(id, buf))
                        continue;
                sprintf(buf, "%p", t);
                if (strcmp(id, buf))
                        continue;

-               t->ret = -E_TASK_KILLED;
-               if (t->event_handler)
-                       t->event_handler(t);
+               t->error = -E_TASK_KILLED;

                return 1;
        }
        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
                sprintf(buf, "%p", t);
                if (strcmp(id, buf))
                        continue;
                return 1;
        }
        list_for_each_entry_safe(t, tmp, &post_select_list, post_select_node) {
                sprintf(buf, "%p", t);
                if (strcmp(id, buf))
                        continue;

-               t->ret = -E_TASK_KILLED;
-               if (t->event_handler)
-                       t->event_handler(t);
+               t->error = -E_TASK_KILLED;

                return 1;
        }
        return -E_NO_SUCH_TASK;
                return 1;
        }
        return -E_NO_SUCH_TASK;