Thread Queue: Merge discipline subroutines into main methods

There was a lot of duplication between the discipline subroutines.
With the transition to RBTrees for priority discipline, there were
only a few lines of source code manipulating the data structure
for FIFO and priority. Thus is made sense to fold these back
into the main methods.

As part of doing this all of the tests for discipline were changed
to be in the same order.

1 files changed, 22 insertions, 7 deletions

diff --git a/cpukit/score/src/threadqfirst.c b/cpukit/score/src/threadqfirst.c
index 7b7999665d..39f7c3f5b3 100644
--- a/cpukit/score/src/threadqfirst.c
+++ b/cpukit/score/src/threadqfirst.c
@@ -6,7 +6,7 @@
  */
 
 /*
- *  COPYRIGHT (c) 1989-2008.
+ *  COPYRIGHT (c) 1989-2014.
  *  On-Line Applications Research Corporation (OAR).
  *
  *  The license and distribution terms for this file may be
@@ -18,18 +18,33 @@
 #include "config.h"
 #endif
 
+#include <rtems/score/chainimpl.h>
+#include <rtems/score/isrlevel.h>
 #include <rtems/score/threadqimpl.h>
 
 Thread_Control *_Thread_queue_First(
   Thread_queue_Control *the_thread_queue
 )
 {
-  Thread_Control * (*first_p)(Thread_queue_Control *);
+  ISR_Level       level;
+  Thread_Control *thread;
 
-  if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_PRIORITY )
-      first_p = _Thread_queue_First_priority;
-  else /* must be THREAD_QUEUE_DISCIPLINE_FIFO */
-      first_p = _Thread_queue_First_fifo;
+  thread = NULL;
 
-  return (*first_p)( the_thread_queue );
+  _ISR_Disable( level );
+
+  if ( the_thread_queue->discipline == THREAD_QUEUE_DISCIPLINE_FIFO ) {
+    if ( !_Chain_Is_empty( &the_thread_queue->Queues.Fifo ) )
+      thread = (Thread_Control *) _Chain_First(&the_thread_queue->Queues.Fifo);
+  } else { /* must be THREAD_QUEUE_DISCIPLINE_PRIORITY */
+    RBTree_Node *first;
+
+    first = _RBTree_First( &the_thread_queue->Queues.Priority, RBT_LEFT );
+    if ( first )
+      thread = _RBTree_Container_of( first, Thread_Control, RBNode );
+  }
+
+  _ISR_Enable( level );
+
+  return thread;
 }