Snapshot of work-in-progress do deal with out-of-bin elements. Current system is very likely going to be ditched due...

Original commit message from CVS:
Snapshot of work-in-progress do deal with out-of-bin elements.  Current
system is very likely going to be ditched due to its complexity and the
fact that it doesn't work right now.  More than that, it's generating some
really odd results in my test program, which aren't readily explainable.

If you want to keep a working copy of your working copy (heh), don't update
until this is replaced with a hybrid approach.  This approach will be the
beginning of a plan generator that can construct full hybrid schedules
given hints from various places.

Hybrid means that cothreads are used, but there are chunks of the pipeline
that are actually dealt with by chaining. This can improve speed by
reducing cothread switches (which are much cheaper than thread switches,
but still far from free, about 570 cycles on my PIII), but does carry a
complexity burden.  Luckily, the structure of GStreamer allows that burden
to live entirely in create_plan.  Luck?  I think not ;-)

gst/gstbin.c

@@ -570,7 +570,7 @@ gst_bin_src_wrapper (int argc,char *argv[])
     while (pads) {
       pad = GST_PAD (pads->data);
       if (pad->direction == GST_PAD_SRC) {
-        region_struct *region = cothread_get_data (element->threadstate, "region");
+        region_struct *region = cothread_get_data (pad->threadstate, "region");
         if (region) {
  	  //gst_src_push_region (GST_SRC (element), region->offset, region->size);
           if (pad->pullregionfunc == NULL) 
@@ -623,11 +623,47 @@ gst_bin_connection_wrapper (int argc,char *argv[])
   return 0;
 }
 
+static int
+gst_bin_sched_wrapper (int argc, char *argv[])
+{
+  _GstBinOutsideSchedule *sched = (_GstBinOutsideSchedule *)argv;
+  GstElement *element = sched->element;
+  GSList *pads;
+  GstPad *pad;
+  region_struct *region;
+  G_GNUC_UNUSED const gchar *name = gst_element_get_name (element);
+
+  DEBUG_ENTER("(\"%s\")",name);
+
+  do {
+    pads = sched->padlist;
+    while (pads) {
+      pad = GST_PAD (pads->data);
+      region = cothread_get_data (pad->threadstate, "region");
+      if (region) {
+        //gst_src_push_region (GST_SRC (element), region->offset, region->size);
+        if (pad->pullregionfunc == NULL)
+          fprintf(stderr,"error, no pullregionfunc in \"%s\"\n", name);
+        (pad->pullregionfunc)(pad, region->offset, region->size);
+      }
+      else {
+        if (pad->pullfunc == NULL)
+          fprintf(stderr,"error, no pullfunc in \"%s\"\n", name);
+        (pad->pullfunc)(pad);
+      }
+    }
+  } while (!(sched->flags && GST_ELEMENT_COTHREAD_STOPPING));
+  sched->flags &= ~GST_ELEMENT_COTHREAD_STOPPING;
+
+  DEBUG_LEAVE("");
+  return 0;
+}
+
 static void 
 gst_bin_pullfunc_proxy (GstPad *pad) 
 {
-  DEBUG_ENTER("(%s)",gst_element_get_name (GST_ELEMENT (pad->parent)));
-  cothread_switch (GST_ELEMENT (pad->parent)->threadstate);
+  DEBUG_ENTER("(%s:%s)",GST_DEBUG_PAD_NAME(pad));
+  cothread_switch (pad->threadstate);
 }
 
 static void 
@@ -637,21 +673,88 @@ gst_bin_pullregionfunc_proxy (GstPad *pad,
 {
   region_struct region;
 
-  DEBUG_ENTER("%s",gst_element_get_name (GST_ELEMENT (pad->parent)));
+  DEBUG_ENTER("%s:%s,%ld,%ld",GST_DEBUG_PAD_NAME(pad),offset,size);
 
   region.offset = offset;
   region.size = size;
 
-  cothread_set_data (GST_ELEMENT (pad->parent)->threadstate, "region", &region);
-  cothread_switch (GST_ELEMENT (pad->parent)->threadstate);
-  cothread_set_data (GST_ELEMENT (pad->parent)->threadstate, "region", NULL);
+  cothread_set_data (pad->threadstate, "region", &region);
+  cothread_switch (pad->threadstate);
+  cothread_set_data (pad->threadstate, "region", NULL);
 }
 
 static void 
 gst_bin_pushfunc_proxy (GstPad *pad) 
 {
-  DEBUG_ENTER("%s",gst_element_get_name (GST_ELEMENT (pad->parent)));
-  cothread_switch (GST_ELEMENT (pad->parent)->threadstate);
+  DEBUG_ENTER("(%s:%s)",GST_DEBUG_PAD_NAME(pad));
+  cothread_switch (pad->threadstate);
+}
+
+/* Creates the plan for a src or connection outside the bin. */
+static _GstBinOutsideSchedule *
+gst_bin_create_plan_outside (GstBin *bin, GstElement *element)
+{
+  GList *pads;
+  GstPad *pad;
+  gboolean dedicated = TRUE;
+  cothread_state *threadstate;
+  _GstBinOutsideSchedule *sched;
+
+  // walk through all the pads, find out of this is hard or not
+  pads = gst_element_get_pad_list (element);
+  while (pads) {
+    pad = GST_PAD (pads->data);
+    // if the pad's peer's parent isn't the Bin, it's hard
+    // FIXME gst_pad_get_parent should return a GstElement
+    if (gst_pad_get_parent (pad->peer) != GST_OBJECT (bin))
+      dedicated = FALSE;
+    pads = g_list_next (pads);
+  }
+
+  // if the element is wholely in the Bin, create a plugin context
+  if (dedicated == TRUE) {
+    if (element->threadstate == NULL) {
+      element->threadstate = cothread_create (bin->threadcontext);
+      DEBUG("created element threadstate %p for \"%s\"\n",element->threadstate,
+            gst_element_get_name(element));
+    }
+    // set the cothread loopfunc
+    if (GST_IS_SRC(element))
+      cothread_setfunc (element->threadstate, gst_bin_src_wrapper,
+                        0, (char **)element);
+    else if (GST_IS_CONNECTION(element))
+      cothread_setfunc (element->threadstate, gst_bin_connection_wrapper,
+                        0, (char **)element);
+  }
+  // otherwise, we have some work to do
+  else {
+    // create a cothread state
+    threadstate = cothread_create (bin->threadcontext);
+
+    // construct an outside schedule struct
+    sched = g_new0(_GstBinOutsideSchedule,1);
+    sched->element = element;
+    sched->bin = bin;
+    sched->threadstate = threadstate;
+
+    // loop through the pads again looking for candidates
+    pads = gst_element_get_pad_list (element);
+    while (pads) {
+      pad = GST_PAD (pads->data);
+      // if the pad's peer's parent is this bin, it's a candidate
+      // FIXME gst_pad_get_parent should return a GstElement
+      if (gst_pad_get_parent (pad->peer) == GST_OBJECT(bin))
+        sched->padlist = g_slist_prepend(sched->padlist,pad);
+      pads = g_list_next (pads);
+    }
+
+    // add this schedule to the list of outside schedules
+    bin->outside_schedules = g_list_prepend(bin->outside_schedules,sched);
+
+    // set the cothread loopfunc
+    cothread_setfunc (sched->threadstate, gst_bin_sched_wrapper,
+                      0, (char **)sched);
+  }
 }
 
 static void
@@ -750,11 +853,11 @@ gst_bin_create_plan_func (GstBin *bin)
         DEBUG("created element threadstate %p for \"%s\"\n",element->threadstate,
               gst_element_get_name(element));
       }
+
       if (GST_IS_BIN (element)) {
         gst_bin_create_plan (GST_BIN (element));
-      }
 
-      if (GST_IS_SRC (element)) {
+      } else if (GST_IS_SRC (element)) {
         DEBUG("adding '%s' as entry point\n",gst_element_get_name (element));
         bin->entries = g_list_prepend (bin->entries,element);
         bin->numentries++;
@@ -764,8 +867,6 @@ gst_bin_create_plan_func (GstBin *bin)
       pads = gst_element_get_pad_list (element);
       while (pads) {
         pad = GST_PAD(pads->data);
-//        DEBUG("setting push&pull handlers for %s:%s\n",GST_DEBUG_PAD_NAME(pad));
-
         if (gst_pad_get_direction (pad) == GST_PAD_SRC) {
           DEBUG("checking/setting push proxy for srcpad %s:%s\n",
                  GST_DEBUG_PAD_NAME(pad));
@@ -774,8 +875,7 @@ gst_bin_create_plan_func (GstBin *bin)
             pad->pushfunc = gst_bin_pushfunc_proxy;
 
         } else if (gst_pad_get_direction (pad) == GST_PAD_SINK) {
-          DEBUG("checking/setting pull proxies for sinkpad %s:%s\n",
-                 GST_DEBUG_PAD_NAME(pad));
+          DEBUG("checking/setting pull proxies for sinkpad %s:%s\n",GST_DEBUG_PAD_NAME(pad));
           // set the proxy functions
           if (!pad->pullfunc)
             pad->pullfunc = gst_bin_pullfunc_proxy;
@@ -791,45 +891,22 @@ gst_bin_create_plan_func (GstBin *bin)
           outside = GST_ELEMENT (gst_pad_get_parent (peer));
           // FIXME this should *really* be an error condition
           if (!outside) break;
-          /* if it's a connection and it's not ours... */
-          if (GST_IS_CONNECTION (outside) &&
+          /* if it's a source or connection and it's not ours... */
+          if ((GST_IS_SRC (outside) || GST_IS_CONNECTION (outside)) &&
                (gst_object_get_parent (GST_OBJECT (outside)) != GST_OBJECT (bin))) {
 
-/***** this is irrelevant now *****
-	    GList *connection_pads = gst_element_get_pad_list (outside);
-            while (connection_pads) {
-              opad = GST_PAD (connection_pads->data);
-              if (gst_pad_get_direction (opad) == GST_PAD_SRC) {
-                g_print("gstbin: setting push&pull handlers for %s:%s SRC connection %p %p\n",
-                        GST_DEBUG_PAD_NAME(pad), opad, opad->pullfunc);
-
-                opad->pushfunc = gst_bin_pushfunc_proxy;
-                opad->pullfunc = gst_bin_pullfunc_proxy;
-        	opad->pullregionfunc = gst_bin_pullregionfunc_proxy;
-
-                cothread_setfunc (outside->threadstate, gst_bin_loopfunc_wrapper,
-                        1, (char **)outside);
-                }
-	      }
-              connection_pads = g_list_next (connection_pads);
-	    }
-            gst_info("gstbin: element \"%s\" is the external source Connection "
-		    "for internal element \"%s\"\n",
-	                  gst_element_get_name (GST_ELEMENT (outside)),
-	                  gst_element_get_name (GST_ELEMENT (element)));
-*****/
-            DEBUG("connection '%s' outside bin is an entry\n",gst_element_get_name(outside));
+            DEBUG("element '%s' outside bin is an entry\n",gst_element_get_name(outside));
+/*
 	    bin->entries = g_list_prepend (bin->entries,outside);
 	    bin->numentries++;
-// FIXME: this won't work in the case where a connection feeds multiple contexts.
-// have to have a list of internal structures of connection entries, struct passed to
-// the cothread wrapper, struct listing pads that enter that context.
             if (outside->threadstate == NULL) {
               outside->threadstate = cothread_create (bin->threadcontext);
               DEBUG("created element threadstate %p for \"%s\"\n",outside->threadstate,
                     gst_element_get_name(outside));
             }
             cothread_setfunc(outside->threadstate,gst_bin_connection_wrapper,0,(char **)outside);
+*/
+            bin->entries = g_list_prepend (bin->entries, gst_bin_create_plan_outside(bin,outside));
 	  }
 	}
         pads = g_list_next (pads);
@@ -896,6 +973,7 @@ gst_bin_iterate_func (GstBin *bin)
   GstElement *entry;
   GList *pads;
   GstPad *pad;
+  _GstBinOutsideSchedule *sched;
 
   DEBUG_SET_STRING("(\"%s\")", gst_element_get_name (GST_ELEMENT (bin)));
   DEBUG_ENTER_STRING;
@@ -908,11 +986,19 @@ gst_bin_iterate_func (GstBin *bin)
     // all we really have to do is switch to the first child
     // FIXME this should be lots more intelligent about where to start
 
-    entry = GST_ELEMENT (bin->children->data);
+    if (GST_IS_ELEMENT(bin->entries->data)) {
+      entry = GST_ELEMENT (bin->entries->data);
       GST_FLAG_SET (entry, GST_ELEMENT_COTHREAD_STOPPING);
       DEBUG("set COTHREAD_STOPPING flag on \"%s\"(%p)\n",
             gst_element_get_name(entry),entry);
       cothread_switch (entry->threadstate);
+    } else {
+      sched = (_GstBinOutsideSchedule *) (bin->entries->data);
+      sched->flags |= GST_ELEMENT_COTHREAD_STOPPING;
+      DEBUG("set COTHREAD STOPPING flag on sched for \"%s\"(%p)\n",
+            gst_element_get_name(sched->element),sched->element);
+      cothread_switch (sched->threadstate);
+    }
 
   } else {
     if (bin->numentries <= 0) {

gst/gstbin.h

@@ -62,6 +62,7 @@ struct _GstBin {
 
   cothread_context *threadcontext;
   gboolean use_cothreads;
+  GList *outside_schedules;
 };
 
 struct _GstBinClass {
@@ -81,6 +82,17 @@ struct _GstBinClass {
   void		(*iterate) 		(GstBin *bin);
 };
 
+/* this struct is used for odd scheduling cases */
+typedef struct __GstBinOutsideSchedule {
+  guint32 flags;
+  GstElement *element;
+  GstBin *bin;
+  cothread_state *threadstate;
+  GSList *padlist;
+} _GstBinOutsideSchedule;
+
+
+
 GtkType 	gst_bin_get_type		(void);
 GstElement*	gst_bin_new			(gchar *name);
 #define 	gst_bin_destroy(bin) 		gst_object_destroy(GST_OBJECT(bin))

gst/gstelement.c

@@ -261,8 +261,8 @@ gst_element_connect (GstElement *src, gchar *srcpadname,
 
   /* obtain the pads requested */
   srcpad = gst_element_get_pad (src, srcpadname);
-  destpad = gst_element_get_pad (dest, destpadname);
   g_return_if_fail (srcpad != NULL);
+  destpad = gst_element_get_pad (dest, destpadname);
   g_return_if_fail (destpad != NULL);
 
   /* find the parent elements of each element */
@@ -270,8 +270,7 @@ gst_element_connect (GstElement *src, gchar *srcpadname,
   destparent = gst_object_get_parent (GST_OBJECT (dest));
   
   /* have to make sure that they have the same parents... */
-  if (srcparent != destparent)
-    return;
+  g_return_if_fail (srcparent == destparent);
 
   /* we're satisified they can be connected, let's do it */
   gst_pad_connect(srcpad,destpad);

gst/gstpad.h

@@ -25,6 +25,7 @@
 #include <gnome-xml/parser.h>
 #include <gst/gstobject.h>
 #include <gst/gstbuffer.h>
+#include <gst/cothreads.h>
 #include <gst/gstcaps.h>
 
 
@@ -72,6 +73,8 @@ struct _GstPad {
   GList *types;
   GstCaps *caps;
 
+  cothread_state *threadstate;
+
   GstPadDirection direction;
 
   GstPad *peer;