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rewrite GstThread - should be quite a bit cleaner and does change state correctly now

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Original commit message from CVS:
rewrite GstThread - should be quite a bit cleaner and does change state correctly now
This commit is contained in:
Benjamin Otte 2003-04-18 23:35:34 +00:00
parent 64a6a1d2bd
commit 90dc6ded4d
2 changed files with 215 additions and 457 deletions
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657
gst/gstthread.c
View file

@ -1,6 +1,7 @@
/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
* 2003 Benjamin Otte <in7y118@public.uni-hamburg.de>
*
* gstthread.c: Threaded container object
*
@ -20,28 +21,22 @@
* Boston, MA 02111-1307, USA.
*/
#include <unistd.h>
/* #define GST_DEBUG_ENABLED */
#include "gst_private.h"
#include "gst.h"
#include "gstthread.h"
#include "gstscheduler.h"
#include "gstqueue.h"
#include "gstinfo.h"
#include "gstlog.h"
#define STACK_SIZE 0x200000
#define g_thread_equal(a,b) ((a) == (b))
GstElementDetails gst_thread_details = {
"Threaded container",
"Generic/Bin",
"LGPL",
"Container that creates/manages a thread",
VERSION,
"Erik Walthinsen <omega@cse.ogi.edu>",
"(C) 1999, 2000",
"Erik Walthinsen <omega@cse.ogi.edu>,"
"Benjamin Otte <in7y118@informatik.uni-hamburg.de",
"(C) 1999-2003",
};
@ -74,8 +69,12 @@ static void gst_thread_set_property (GObject *object, guint prop_id,
const GValue *value, GParamSpec *pspec);
static void gst_thread_get_property (GObject *object, guint prop_id,
GValue *value, GParamSpec *pspec);
static
GstElementStateReturn gst_thread_change_state (GstElement *element);
static GstElementStateReturn gst_thread_change_state (GstElement *element);
static void gst_thread_child_state_change (GstBin *bin, GstElementState oldstate,
GstElementState newstate, GstElement *element);
static void gst_thread_catch (GstThread *thread);
static void gst_thread_release (GstThread *thread);
#ifndef GST_DISABLE_LOADSAVE
static xmlNodePtr gst_thread_save_thyself (GstObject *object,
@ -84,7 +83,7 @@ static void gst_thread_restore_thyself (GstObject *object,
xmlNodePtr self);
#endif
static void* gst_thread_main_loop (void *arg);
static void * gst_thread_main_loop (void *arg);
#define GST_TYPE_THREAD_PRIORITY (gst_thread_priority_get_type())
static GType
@ -107,6 +106,7 @@ gst_thread_priority_get_type(void)
static GstBinClass *parent_class = NULL;
static guint gst_thread_signals[LAST_SIGNAL] = { 0 };
GPrivate *gst_thread_current;
GType
gst_thread_get_type(void) {
@ -127,6 +127,7 @@ gst_thread_get_type(void) {
return thread_type;
}
static void do_nothing (gpointer hi) {}
static void
gst_thread_class_init (GstThreadClass *klass)
{
@ -135,6 +136,9 @@ gst_thread_class_init (GstThreadClass *klass)
GstElementClass *gstelement_class;
GstBinClass *gstbin_class;
/* setup gst_thread_current */
gst_thread_current = g_private_new (do_nothing);
gobject_class = (GObjectClass*)klass;
gstobject_class = (GstObjectClass*)klass;
gstelement_class = (GstElementClass*)klass;
@ -163,6 +167,7 @@ gst_thread_class_init (GstThreadClass *klass)
gobject_class->set_property = GST_DEBUG_FUNCPTR (gst_thread_set_property);
gobject_class->get_property = GST_DEBUG_FUNCPTR (gst_thread_get_property);
gstbin_class->child_state_change = GST_DEBUG_FUNCPTR (gst_thread_child_state_change);
}
static void
@ -181,13 +186,10 @@ gst_thread_init (GstThread *thread)
g_assert (scheduler);
thread->lock = g_mutex_new ();
thread->cond_t = g_cond_new ();
thread->cond_m = g_cond_new ();
thread->cond = g_cond_new ();
thread->ppid = getpid ();
thread->thread_id = (GThread *) NULL; /* set in NULL -> READY */
thread->priority = G_THREAD_PRIORITY_NORMAL;
thread->stack = NULL;
}
static void
@ -195,23 +197,16 @@ gst_thread_dispose (GObject *object)
{
GstThread *thread = GST_THREAD (object);
GST_DEBUG (GST_CAT_REFCOUNTING, "dispose");
g_mutex_lock (thread->lock);
if (GST_STATE (thread) != GST_STATE_NULL) {
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
}
g_mutex_unlock (thread->lock);
gst_element_set_state (GST_ELEMENT (thread), GST_STATE_NULL);
g_mutex_free (thread->lock);
g_cond_free (thread->cond_t);
g_cond_free (thread->cond_m);
gst_object_replace ((GstObject **)&GST_ELEMENT_SCHED (thread), NULL);
GST_DEBUG (GST_CAT_REFCOUNTING, "GstThread: dispose");
G_OBJECT_CLASS (parent_class)->dispose (object);
g_assert (GST_STATE (thread) == GST_STATE_NULL);
g_mutex_free (thread->lock);
g_cond_free (thread->cond);
gst_object_replace ((GstObject **)&GST_ELEMENT_SCHED (thread), NULL);
}
/**
@ -278,323 +273,214 @@ gst_thread_new (const gchar *name)
return gst_element_factory_make ("thread", name);
}
/* these two macros are used for debug/info from the state_change function */
/* FIXME: with some rearranging of output or otherwise we could probably
* get rid of this g_strdup_printf we're using here, so go ahead if you're
* concerned about this slowing down */
#ifdef G_HAVE_ISO_VARARGS
#define THR_INFO(...) \
{ \
gchar *val = g_strdup_printf(__VA_ARGS__); \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, \
"sync(" GST_DEBUG_THREAD_FORMAT "): %s", \
GST_DEBUG_THREAD_ARGS(thread->pid), val); \
g_free(val); \
}
#define THR_DEBUG(...) \
{ \
gchar *val = g_strdup_printf(__VA_ARGS__); \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, \
"sync(" GST_DEBUG_THREAD_FORMAT "): %s", \
GST_DEBUG_THREAD_ARGS(thread->pid), val); \
g_free(val); \
}
/* these two macros are used for debug/info from the gst_thread_main_loop
* function
/**
* gst_thread_get_current:
*
* Create a new thread with the given name.
*
* Returns: The current GstThread or NULL if you are not running inside a
* #GstThread.
*/
#define THR_INFO_MAIN(...) \
{ \
gchar *val = g_strdup_printf(__VA_ARGS__); \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, \
"sync-main(" GST_DEBUG_THREAD_FORMAT "): %s", \
GST_DEBUG_THREAD_ARGS(thread->pid), val); \
g_free(val); \
}
#define THR_DEBUG_MAIN(...) \
{ \
gchar *val = g_strdup_printf(__VA_ARGS__); \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, \
"sync-main(" GST_DEBUG_THREAD_FORMAT "): %s", \
GST_DEBUG_THREAD_ARGS(thread->pid), val); \
g_free(val); \
}
#elif defined(G_HAVE_GNUC_VARARGS)
#define THR_INFO(format,args...) \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, "sync(" GST_DEBUG_THREAD_FORMAT "): " format , \
GST_DEBUG_THREAD_ARGS(thread->pid) , ## args )
#define THR_DEBUG(format,args...) \
GST_DEBUG_ELEMENT(GST_CAT_THREAD, thread, "sync(" GST_DEBUG_THREAD_FORMAT "): " format , \
GST_DEBUG_THREAD_ARGS(thread->pid) , ## args )
/* these two macros are used for debug/info from the gst_thread_main_loop
* function
*/
#define THR_INFO_MAIN(format,args...) \
GST_INFO_ELEMENT(GST_CAT_THREAD, thread, "sync-main(" GST_DEBUG_THREAD_FORMAT "): " format , \
GST_DEBUG_THREAD_ARGS(thread->ppid) , ## args )
#define THR_DEBUG_MAIN(format,args...) \
GST_DEBUG_ELEMENT(GST_CAT_THREAD, thread, "sync-main(" GST_DEBUG_THREAD_FORMAT "): " format , \
GST_DEBUG_THREAD_ARGS(thread->ppid) , ## args )
#endif
static GstElementStateReturn
gst_thread_update_state (GstThread *thread)
GstThread *
gst_thread_get_current (void)
{
GST_DEBUG_ELEMENT (GST_CAT_THREAD, thread, "updating state of thread");
/* check for state change */
if (GST_STATE_PENDING (thread) != GST_STATE_VOID_PENDING) {
/* punt and change state on all the children */
if (GST_ELEMENT_CLASS (parent_class)->change_state)
return GST_ELEMENT_CLASS (parent_class)->change_state (GST_ELEMENT (thread));
}
/* FIXME: in the case of no change_state function in the parent's class,
* shouldn't we actually change the thread's state ? */
g_warning ("thread's parent doesn't have change_state, returning success");
return GST_STATE_SUCCESS;
return (GstThread *) g_private_get (gst_thread_current);
}
static inline void
gst_thread_release_children_locks (GstThread *thread)
{
GstRealPad *peer = NULL;
GstElement *peerelement;
GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
while (elements) {
GstElement *element = GST_ELEMENT (elements->data);
GList *pads;
g_assert (element);
GST_DEBUG (GST_CAT_THREAD, "waking element \"%s\"", GST_ELEMENT_NAME (element));
elements = g_list_next (elements);
if (!gst_element_release_locks (element))
g_warning ("element %s could not release locks", GST_ELEMENT_NAME (element));
pads = GST_ELEMENT_PADS (element);
while (pads) {
if (GST_PAD_PEER (pads->data)) {
peer = GST_REAL_PAD (GST_PAD_PEER (pads->data));
pads = g_list_next (pads);
} else {
pads = g_list_next (pads);
continue;
}
if (!peer)
continue;
peerelement = GST_PAD_PARENT (peer);
if (!peerelement)
continue; /* FIXME: deal with case where there's no peer */
if (GST_ELEMENT_SCHED (peerelement) != GST_ELEMENT_SCHED (thread)) {
GST_DEBUG (GST_CAT_THREAD, "element \"%s\" has pad cross sched boundary", GST_ELEMENT_NAME (element));
GST_DEBUG (GST_CAT_THREAD, "waking element \"%s\"", GST_ELEMENT_NAME (peerelement));
if (!gst_element_release_locks (peerelement))
g_warning ("element %s could not release locks", GST_ELEMENT_NAME (peerelement));
}
}
}
}
/* stops the main thread, if there is one and grabs the thread's mutex */
static void
gst_thread_catch (GstThread *thread)
{
gboolean wait;
g_mutex_lock (thread->lock);
if (thread != gst_thread_get_current()) {
/* another thread is trying to catch us */
wait = !GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING);
while (!wait) {
GTimeVal tv;
GST_DEBUG (GST_CAT_THREAD, "catching %s...", GST_ELEMENT_NAME (thread));
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
g_cond_signal (thread->cond);
gst_thread_release_children_locks (thread);
g_get_current_time (&tv);
g_time_val_add (&tv, 1000); /* wait a millisecond to catch the thread */
wait = g_cond_timed_wait (thread->cond, thread->lock, &tv);
}
GST_DEBUG (GST_CAT_THREAD, "caught %s", GST_ELEMENT_NAME (thread));
}
g_assert (!GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING));
}
static void
gst_thread_release (GstThread *thread)
{
g_cond_signal (thread->cond);
g_mutex_unlock (thread->lock);
}
static GstElementStateReturn
gst_thread_change_state (GstElement *element)
{
GstThread *thread;
gboolean stateset = GST_STATE_SUCCESS;
gint transition;
GThread *self = g_thread_self ();
GError *error = NULL;
GstElementStateReturn ret;
g_return_val_if_fail (GST_IS_THREAD (element), GST_STATE_FAILURE);
g_return_val_if_fail (gst_has_threads (), GST_STATE_FAILURE);
thread = GST_THREAD (element);
transition = GST_STATE_TRANSITION (element);
GST_DEBUG (GST_CAT_STATES, "%s is changing state from %s to %s",
GST_ELEMENT_NAME (element), gst_element_state_get_name (GST_STATE (element)),
gst_element_state_get_name (GST_STATE_PENDING (element)));
THR_INFO ("changing state from %s to %s",
gst_element_state_get_name (GST_STATE (element)),
gst_element_state_get_name (GST_STATE_PENDING (element)));
gst_thread_catch (thread);
if (g_thread_equal (self, thread->thread_id)) {
GST_DEBUG (GST_CAT_THREAD,
"no sync(" GST_DEBUG_THREAD_FORMAT "): "
"setting own thread's state to spinning",
GST_DEBUG_THREAD_ARGS (thread->pid));
return gst_thread_update_state (thread);
}
switch (transition) {
switch (GST_STATE_TRANSITION (element)) {
case GST_STATE_NULL_TO_READY:
/* set the state to idle */
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
THR_DEBUG ("creating thread \"%s\"", GST_ELEMENT_NAME (element));
/* this bit of code handles creation of GThreads
* this is therefor tricky code
* compare it with the block of code that handles the destruction
* in GST_STATE_READY_TO_NULL below
*/
g_mutex_lock (thread->lock);
/* create a new GThread
* use the specified attributes
* make it execute gst_thread_main_loop (thread)
*/
GST_DEBUG (GST_CAT_THREAD, "going to g_thread_create_full...");
/* create the thread */
GST_FLAG_UNSET (thread, GST_THREAD_STATE_REAPING);
thread->thread_id = g_thread_create_full(gst_thread_main_loop,
thread, STACK_SIZE, TRUE, TRUE, thread->priority,
&error);
thread, STACK_SIZE, FALSE, TRUE, thread->priority,
NULL);
if (!thread->thread_id){
GST_DEBUG (GST_CAT_THREAD, "g_thread_create_full failed");
g_mutex_unlock (thread->lock);
GST_DEBUG (GST_CAT_THREAD, "could not create thread \"%s\"",
GST_ELEMENT_NAME (element));
return GST_STATE_FAILURE;
GST_DEBUG (GST_CAT_THREAD, "g_thread_create_full for %sfailed", GST_ELEMENT_NAME (element));
goto error_out;
}
GST_DEBUG (GST_CAT_THREAD, "GThread created");
/* wait for it to 'spin up' */
THR_DEBUG ("waiting for child thread spinup");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("thread claims to be up");
g_mutex_unlock (thread->lock);
g_cond_wait (thread->cond, thread->lock);
break;
case GST_STATE_READY_TO_PAUSED:
THR_INFO ("readying thread");
g_mutex_lock (thread->lock);
THR_DEBUG ("signaling");
g_cond_signal (thread->cond_t);
THR_DEBUG ("waiting for ack");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("got ack");
g_mutex_unlock (thread->lock);
break;
case GST_STATE_PAUSED_TO_PLAYING:
{
/* fixme: recurse into sub-bins */
const GList *elements = gst_bin_get_list (GST_BIN (thread));
/* FIXME: recurse into sub-bins */
GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
while (elements) {
gst_element_enable_threadsafe_properties ((GstElement*)elements->data);
elements = g_list_next (elements);
}
THR_DEBUG ("telling thread to start spinning");
g_mutex_lock (thread->lock);
THR_DEBUG ("signaling");
g_cond_signal (thread->cond_t);
THR_DEBUG ("waiting for ack");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("got ack");
g_mutex_unlock (thread->lock);
/* we're actually doing async notification, the state could
* have changed already (eg. EOS) here. commented out as
* it needs more thinking... */
/* stateset = GST_STATE_ASYNC; */
break;
}
case GST_STATE_PLAYING_TO_PAUSED:
{
const GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
THR_INFO ("pausing thread");
/* the following code ensures that the bottom half of thread will run
* to perform each elements' change_state() (by calling gstbin.c::
* change_state()).
* + the pending state was already set by gstelement.c::set_state()
* + unlock all elements so the bottom half can start the state change.
*/
g_mutex_lock (thread->lock);
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
while (elements) {
GstElement *element = GST_ELEMENT (elements->data);
GList *pads;
g_assert (element);
THR_DEBUG (" waking element \"%s\"", GST_ELEMENT_NAME (element));
elements = g_list_next (elements);
if (!gst_element_release_locks (element)) {
g_warning ("element %s could not release locks",
GST_ELEMENT_NAME (element));
}
pads = GST_ELEMENT_PADS (element);
while (pads) {
GstRealPad *peer = NULL;
GstElement *peerelement;
if (GST_PAD_PEER (pads->data))
peer = GST_REAL_PAD (GST_PAD_PEER (pads->data));
pads = g_list_next (pads);
if (!peer)
continue;
peerelement = GST_PAD_PARENT (peer);
if (!peerelement)
continue; /* deal with case where there's no peer */
if (!GST_FLAG_IS_SET (peerelement, GST_ELEMENT_DECOUPLED)) {
GST_DEBUG (GST_CAT_THREAD, "peer element isn't DECOUPLED");
continue;
}
if (GST_ELEMENT_SCHED (peerelement) != GST_ELEMENT_SCHED (thread)) {
THR_DEBUG (" element \"%s\" has pad cross sched boundary", GST_ELEMENT_NAME (element));
THR_DEBUG (" waking element \"%s\"", GST_ELEMENT_NAME (peerelement));
if (!gst_element_release_locks (peerelement)) {
g_warning ("element %s could not release locks", GST_ELEMENT_NAME (peerelement));
}
}
}
}
THR_DEBUG ("telling thread to pause, signaling");
g_cond_signal (thread->cond_t);
THR_DEBUG ("waiting for ack");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("got ack");
g_mutex_unlock (thread->lock);
elements = gst_bin_get_list (GST_BIN (thread));
GList *elements = (GList *) gst_bin_get_list (GST_BIN (thread));
while (elements) {
gst_element_disable_threadsafe_properties ((GstElement*)elements->data);
elements = g_list_next (elements);
}
break;
}
case GST_STATE_READY_TO_NULL:
THR_DEBUG ("telling thread to pause (null) - and joining");
/* MattH FIXME revisit */
g_mutex_lock (thread->lock);
THR_DEBUG ("signaling");
g_cond_signal (thread->cond_t);
THR_DEBUG ("waiting for ack");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("got ack");
/* this block of code is very tricky
* basically, we try to clean up the whole thread and
* everything related to it in the right order without
* triggering segfaults
* compare this block to the block
*/
GST_DEBUG (GST_CAT_THREAD, "joining GThread %p", thread->thread_id);
g_thread_join (thread->thread_id);
thread->thread_id = NULL;
thread->stack = NULL;
THR_DEBUG ("unlocking mutex");
g_mutex_unlock (thread->lock);
GST_FLAG_UNSET (thread, GST_THREAD_STATE_REAPING);
GST_FLAG_UNSET (thread, GST_THREAD_STATE_STARTED);
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
break;
case GST_STATE_PAUSED_TO_READY:
THR_DEBUG ("telling thread to stop spinning");
g_mutex_lock (thread->lock);
THR_DEBUG ("signaling");
g_cond_signal (thread->cond_t);
THR_DEBUG ("waiting for ack");
g_cond_wait (thread->cond_m, thread->lock);
THR_DEBUG ("got ack");
g_mutex_unlock (thread->lock);
break;
case GST_STATE_READY_TO_NULL:
/* we can't join the threads here, because this could have been triggered
by ourself (ouch) */
GST_DEBUG (GST_CAT_THREAD, "destroying GThread %p", thread->thread_id);
GST_FLAG_SET (thread, GST_THREAD_STATE_REAPING);
thread->thread_id = NULL;
if (thread == gst_thread_get_current()) {
/* or should we continue? */
g_warning ("Thread %s is destroying itself. Function call will not return!", GST_ELEMENT_NAME (thread));
gst_scheduler_reset (GST_ELEMENT_SCHED (thread));
/* unlock and signal - we are out */
gst_thread_release (thread);
GST_INFO (GST_CAT_THREAD, "gstthread: thread \"%s\" is stopped",
GST_ELEMENT_NAME (thread));
g_signal_emit (G_OBJECT (thread), gst_thread_signals[SHUTDOWN], 0);
g_thread_exit (NULL);
}
/* now wait for the thread to destroy itself */
g_cond_signal (thread->cond);
g_cond_wait (thread->cond, thread->lock);
/* it should be dead now */
break;
default:
GST_DEBUG_ELEMENT (GST_CAT_THREAD, element, "UNHANDLED STATE CHANGE! %x", transition);
GST_DEBUG_ELEMENT (GST_CAT_THREAD, element, "UNHANDLED STATE CHANGE! %x",
GST_STATE_TRANSITION (element));
g_assert_not_reached ();
break;
}
return stateset;
if (GST_ELEMENT_CLASS (parent_class)->change_state) {
ret = GST_ELEMENT_CLASS (parent_class)->change_state (GST_ELEMENT (thread));
} else {
ret = GST_STATE_SUCCESS;
}
gst_thread_release (thread);
return ret;
error_out:
GST_DEBUG (GST_CAT_STATES, "changing state from %s to %s failed for %s",
gst_element_state_get_name (GST_STATE (element)),
gst_element_state_get_name (GST_STATE_PENDING (element)),
GST_ELEMENT_NAME (element));
gst_thread_release (thread);
return GST_STATE_FAILURE;
}
/* state changes work this way: We grab the lock and stop the thread from
spinning (via gst_thread_catch) - then we change the state. After that the
thread may spin on. */
static void
gst_thread_child_state_change (GstBin *bin, GstElementState oldstate,
GstElementState newstate, GstElement *element)
{
parent_class->child_state_change (bin, oldstate, newstate, element);
/* We'll wake up the main thread now. Note that we can't lock the thread here,
because we might be called from inside gst_thread_change_state when holding
the lock. But this doesn't cause any problems. */
if (newstate == GST_STATE_PLAYING)
g_cond_signal (GST_THREAD (bin)->cond);
}
/**
* gst_thread_main_loop:
* @arg: the thread to start
@ -606,172 +492,49 @@ static void *
gst_thread_main_loop (void *arg)
{
GstThread *thread = NULL;
gint stateset;
glong page_size;
gpointer stack_pointer;
gulong stack_offset;
gboolean status;
GST_DEBUG (GST_CAT_THREAD, "gst_thread_main_loop started");
thread = GST_THREAD (arg);
g_mutex_lock (thread->lock);
GST_DEBUG (GST_CAT_THREAD, "Thread %s started main loop", GST_ELEMENT_NAME (thread));
/* initialize gst_thread_current */
g_private_set (gst_thread_current, thread);
/* set up the element's scheduler */
gst_scheduler_setup (GST_ELEMENT_SCHED (thread));
GST_FLAG_UNSET (thread, GST_THREAD_STATE_REAPING);
thread->pid = getpid();
THR_INFO_MAIN ("thread is running");
page_size = sysconf(_SC_PAGESIZE);
stack_pointer = (gpointer) &stack_pointer;
if(((gulong)stack_pointer & (page_size-1)) < (page_size>>1)){
/* stack grows up, I think */
/* FIXME this is probably not true for the main thread */
stack_offset = (gulong)stack_pointer & (page_size - 1);
}else{
/* stack grows down, I think */
stack_offset = STACK_SIZE - ((gulong)stack_pointer & (page_size - 1));
}
/* note the subtlety with pointer arithmetic */
thread->stack = stack_pointer - stack_offset;
thread->stack_size = STACK_SIZE;
/* first we need to change the state of all the children */
if (GST_ELEMENT_CLASS (parent_class)->change_state) {
stateset = GST_ELEMENT_CLASS (parent_class)->change_state (GST_ELEMENT(thread));
if (stateset != GST_STATE_SUCCESS) {
THR_DEBUG_MAIN ("state change of children failed");
g_cond_signal (thread->cond);
while (!(GST_FLAG_IS_SET (thread, GST_THREAD_STATE_REAPING))) {
if (GST_STATE (thread) == GST_STATE_PLAYING) {
GST_FLAG_SET (thread, GST_THREAD_STATE_SPINNING);
status = TRUE;
GST_DEBUG (GST_CAT_THREAD, "%s starts iterating\n", GST_ELEMENT_NAME (thread));
while (status && GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING)) {
g_mutex_unlock (thread->lock);
status = gst_bin_iterate (GST_BIN (thread));
g_mutex_lock (thread->lock);
}
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
}
if (GST_FLAG_IS_SET (thread, GST_THREAD_STATE_REAPING))
break;
GST_DEBUG (GST_CAT_THREAD, "%s was caught\n", GST_ELEMENT_NAME (thread));
g_cond_signal (thread->cond);
g_cond_wait (thread->cond, thread->lock);
}
THR_DEBUG_MAIN ("indicating spinup");
g_cond_signal (thread->cond_m);
/* don't unlock the mutex because we hold it into the top of the while loop */
THR_DEBUG_MAIN ("thread has indicated spinup to parent process");
/***** THREAD IS NOW IN READY STATE *****/
/* CR1: most of this code is handshaking */
/* do this while the thread lives */
while (!GST_FLAG_IS_SET (thread, GST_THREAD_STATE_REAPING)) {
/* NOTE we hold the thread lock at this point */
/* what we do depends on what state we're in */
switch (GST_STATE (thread)) {
/* NOTE: cannot be in NULL, we're not running in that state at all */
case GST_STATE_READY:
/* wait to be set to either the NULL or PAUSED states */
THR_DEBUG_MAIN ("thread in %s state, waiting for either %s or %s",
gst_element_state_get_name (GST_STATE_READY),
gst_element_state_get_name (GST_STATE_NULL),
gst_element_state_get_name (GST_STATE_PAUSED));
g_cond_wait (thread->cond_t, thread->lock);
/* this must have happened by a state change in the thread context */
if (GST_STATE_PENDING (thread) != GST_STATE_NULL &&
GST_STATE_PENDING (thread) != GST_STATE_PAUSED) {
g_cond_signal (thread->cond_m);
continue;
}
/* been signaled, we need to state transition now and signal back */
gst_thread_update_state (thread);
/* now we decide what to do next */
if (GST_STATE (thread) == GST_STATE_NULL) {
/* REAPING must be set, we can simply break this iteration */
THR_DEBUG_MAIN ("set GST_THREAD_STATE_REAPING");
GST_FLAG_SET (thread, GST_THREAD_STATE_REAPING);
}
THR_DEBUG_MAIN ("done with state transition, "
"signaling back to parent process");
g_cond_signal (thread->cond_m);
continue;
case GST_STATE_PAUSED:
/* wait to be set to either the READY or PLAYING states */
THR_DEBUG_MAIN ("thread in %s state, waiting for either %s or %s",
gst_element_state_get_name (GST_STATE_PAUSED),
gst_element_state_get_name (GST_STATE_READY),
gst_element_state_get_name (GST_STATE_PLAYING));
g_cond_wait (thread->cond_t, thread->lock);
/* this must have happened by a state change in the thread context */
if (GST_STATE_PENDING (thread) != GST_STATE_READY &&
GST_STATE_PENDING (thread) != GST_STATE_PLAYING) {
g_cond_signal (thread->cond_m);
continue;
}
/* been signaled, we need to state transition now and signal back */
gst_thread_update_state (thread);
/* now we decide what to do next */
if (GST_STATE (thread) != GST_STATE_PLAYING) {
/* either READY or the state change failed for some reason */
g_cond_signal (thread->cond_m);
continue;
}
else {
GST_FLAG_SET (thread, GST_THREAD_STATE_SPINNING);
/* PLAYING is coming up, so we can now start spinning */
while (GST_FLAG_IS_SET (thread, GST_THREAD_STATE_SPINNING)) {
gboolean status;
g_cond_signal (thread->cond_m);
g_mutex_unlock (thread->lock);
status = gst_bin_iterate (GST_BIN (thread));
g_mutex_lock (thread->lock);
/* g_cond_signal(thread->cond); */
if (!status || GST_STATE_PENDING (thread) != GST_STATE_VOID_PENDING)
GST_FLAG_UNSET (thread, GST_THREAD_STATE_SPINNING);
}
/* looks like we were stopped because of a statechange */
if (GST_STATE_PENDING (thread) != GST_STATE_VOID_PENDING) {
gst_thread_update_state (thread);
}
/* once we're here, SPINNING has stopped, we should signal that we're done */
THR_DEBUG_MAIN ("SPINNING stopped, signaling back to parent process");
g_cond_signal (thread->cond_m);
/* now we can wait for PAUSED */
continue;
}
case GST_STATE_PLAYING:
/* wait to be set to PAUSED */
THR_DEBUG_MAIN ("thread in %s state, waiting for %s",
gst_element_state_get_name (GST_STATE_PLAYING),
gst_element_state_get_name (GST_STATE_PAUSED));
g_cond_wait (thread->cond_t,thread->lock);
/* been signaled, we need to state transition now and signal back */
gst_thread_update_state (thread);
g_cond_signal (thread->cond_m);
/* now we decide what to do next */
/* there's only PAUSED, we we just wait for it */
continue;
case GST_STATE_NULL:
THR_DEBUG_MAIN ("thread in %s state, preparing to die",
gst_element_state_get_name (GST_STATE_NULL));
GST_FLAG_SET (thread, GST_THREAD_STATE_REAPING);
break;
default:
g_assert_not_reached ();
break;
}
}
/* THREAD HAS STOPPED RUNNING */
/* we need to destroy the scheduler here because it has mapped it's
* stack into the threads stack space */
gst_scheduler_reset (GST_ELEMENT_SCHED (thread));
/* since we don't unlock at the end of the while loop, do it here */
/* unlock and signal - we are out */
g_cond_signal (thread->cond);
g_mutex_unlock (thread->lock);
GST_INFO (GST_CAT_THREAD, "gstthread: thread \"%s\" is stopped",
GST_ELEMENT_NAME (thread));
GST_ELEMENT_NAME (thread));
g_signal_emit (G_OBJECT (thread), gst_thread_signals[SHUTDOWN], 0);

15
gst/gstthread.h
View file

@ -31,6 +31,7 @@
G_BEGIN_DECLS
extern GPrivate *gst_thread_current;
extern GstElementDetails gst_thread_details;
@ -58,15 +59,9 @@ struct _GstThread {
GThread *thread_id; /* id of the thread, if any */
GThreadPriority priority;
gpointer *stack;
guint stack_size; /* stack size */
gint pid; /* the pid of the thread */
gint ppid; /* the pid of the thread's parent process */
GMutex *lock; /* thread lock/condititon pairs */
GCond *cond_t; /* used to control the thread */
GCond *cond_m; /* used to control main thread */
gint transition; /* the current state transition */
GMutex *lock; /* thread lock/condititon pairs */
GCond *cond; /* used to control the thread */
gpointer dummy[8];
};
@ -85,9 +80,9 @@ GType gst_thread_get_type (void);
GstElement* gst_thread_new (const gchar *name);
void gst_thread_set_priority (GstThread *thread, GThreadPriority priority);
GstThread * gst_thread_get_current (void);
G_END_DECLS
#endif /* __GST_THREAD_H__ */
#endif /* __GST_THREAD_H__ */