Minor changes to new queue functions plus add comments.

git-svn-id: https://freertos.svn.sourceforge.net/svnroot/freertos/trunk@705 1d2547de-c912-0410-9cb9-b8ca96c0e9e2

1 files changed, 58 insertions, 37 deletions

diff --git a/Source/queue.c b/Source/queue.c
index 4f093f29..d4e0b819 100644
--- a/Source/queue.c
+++ b/Source/queue.c
@@ -445,6 +445,10 @@ signed portBASE_TYPE xQueueGenericSend( xQueueHandle pxQueue, const void * const
 signed portBASE_TYPE xEntryTimeSet = pdFALSE;

 xTimeOutType xTimeOut;

 

+	/* This function relaxes the coding standard somewhat to allow return

+	statements within the function itself.  This is done in the interest

+	of execution time efficiency. */

+

 	for( ;; )

 	{

 		taskENTER_CRITICAL();

@@ -463,7 +467,9 @@ xTimeOutType xTimeOut;
 					if( xTaskRemoveFromEventList( &( pxQueue->xTasksWaitingToReceive ) ) == pdTRUE )

 					{

 						/* The unblocked task has a priority higher than

-						our own so yield immediately. */

+						our own so yield immediately.  Yes it is ok to do

+						this from within the critical section - the kernel

+						takes care of that. */

 						taskYIELD();

 					}

 				}

@@ -475,11 +481,15 @@ xTimeOutType xTimeOut;
 			{

 				if( xTicksToWait == ( portTickType ) 0 )

 				{

+					/* The queue was full and no block time is specified (or 

+					the block time has expired) so leave now. */

 					taskEXIT_CRITICAL();

 					return errQUEUE_FULL;

 				}

 				else if( xEntryTimeSet == pdFALSE )

 				{

+					/* The queue was full and a block time was specified so

+					configure the timeout structure. */

 					vTaskSetTimeOutState( &xTimeOut );

 					xEntryTimeSet = pdTRUE;

 				}

@@ -487,16 +497,17 @@ xTimeOutType xTimeOut;
 		}

 		taskEXIT_CRITICAL();	

 

+		/* Interrupts and other tasks can send to and receive from the queue

+		now the critical section has been exited. */

+

 		vTaskSuspendAll();

 		prvLockQueue( pxQueue );

 

-		if( prvIsQueueFull( pxQueue ) )

+		/* Update the timeout state to see if it has expired yet. */

+		if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

 		{

-	    	/* Need to call xTaskCheckForTimeout again as time could

-	    	have passed since it was last called if this is not the

-	    	first time around this loop.  */

-			if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

-			{

+			if( prvIsQueueFull( pxQueue ) )

+			{		

 				traceBLOCKING_ON_QUEUE_SEND( pxQueue );

 				vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );

 

@@ -519,15 +530,17 @@ xTimeOutType xTimeOut;
 			}

 			else

 			{

+				/* Try again. */

 				prvUnlockQueue( pxQueue );

-				( void ) xTaskResumeAll();

-				return errQUEUE_FULL;

+				( void ) xTaskResumeAll();			

 			}

 		}

 		else

 		{

+			/* The timeout has expired. */

 			prvUnlockQueue( pxQueue );

 			( void ) xTaskResumeAll();

+			return errQUEUE_FULL;

 		}

 	}

 }

@@ -584,22 +597,19 @@ xTimeOutType xTimeOut;
 

 			taskENTER_CRITICAL();

 			{

-				if( prvIsQueueFull( pxQueue ) )

+				if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

 				{

-	    			/* Need to call xTaskCheckForTimeout again as time could

-	    			have passed since it was last called if this is not the

-	    			first time around this loop.  */

-					if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

-					{

+					if( prvIsQueueFull( pxQueue ) )

+					{				

 						traceBLOCKING_ON_QUEUE_SEND( pxQueue );

 						vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToSend ), xTicksToWait );

 						taskYIELD();

 					}

-					else

-					{

-						taskEXIT_CRITICAL();

-						return errQUEUE_FULL;

-					}

+				}

+				else

+				{

+					taskEXIT_CRITICAL();

+					return errQUEUE_FULL;

 				}

 			}

 			taskEXIT_CRITICAL();

@@ -698,13 +708,10 @@ xTimeOutType xTimeOut;
 

 			taskENTER_CRITICAL();

 			{

-				if( prvIsQueueEmpty( pxQueue ) )

+				if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

 				{

-    				/* Need to call xTaskCheckForTimeout again as time could

-    				have passed since it was last called if this is not the

-    				first time around this loop. */

-					if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

-					{

+					if( prvIsQueueEmpty( pxQueue ) )

+					{				

 						traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );

 

 						#if ( configUSE_MUTEXES == 1 )

@@ -721,11 +728,11 @@ xTimeOutType xTimeOut;
 						vTaskPlaceOnEventList( &( pxQueue->xTasksWaitingToReceive ), xTicksToWait );

 						taskYIELD();

 					}

-					else

-					{

-						taskEXIT_CRITICAL();

-						return errQUEUE_EMPTY;

-					}

+				}

+				else

+				{

+					taskEXIT_CRITICAL();

+					return errQUEUE_EMPTY;

 				}

 			}

 			taskEXIT_CRITICAL();

@@ -795,10 +802,16 @@ signed portBASE_TYPE xEntryTimeSet = pdFALSE;
 xTimeOutType xTimeOut;

 signed portCHAR *pcOriginalReadPosition;

 

+	/* This function relaxes the coding standard somewhat to allow return

+	statements within the function itself.  This is done in the interest

+	of execution time efficiency. */

+

 	for( ;; )

 	{

 		taskENTER_CRITICAL();

 		{

+  			/* Is there space on the queue now?  To be running we must be

+  			the highest priority task wanting to access the queue. */		

 			if( pxQueue->uxMessagesWaiting > ( unsigned portBASE_TYPE ) 0 )

 			{

 				/* Remember our read position in case we are just peeking. */

@@ -862,11 +875,15 @@ signed portCHAR *pcOriginalReadPosition;
 			{

 				if( xTicksToWait == ( portTickType ) 0 )

 				{

+					/* The queue was empty and no block time is specified (or 

+					the block time has expired) so leave now. */				

 					taskEXIT_CRITICAL();

 					return errQUEUE_EMPTY;

 				}

 				else if( xEntryTimeSet == pdFALSE )

 				{

+					/* The queue was empty and a block time was specified so

+					configure the timeout structure. */				

 					vTaskSetTimeOutState( &xTimeOut );

 					xEntryTimeSet = pdTRUE;

 				}

@@ -874,15 +891,16 @@ signed portCHAR *pcOriginalReadPosition;
 		}

 		taskEXIT_CRITICAL();

 

+		/* Interrupts and other tasks can send to and receive from the queue

+		now the critical section has been exited. */

+

 		vTaskSuspendAll();

 		prvLockQueue( pxQueue );

 

-		if( prvIsQueueEmpty( pxQueue ) )

+		/* Update the timeout state to see if it has expired yet. */

+		if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

 		{

-    		/* Need to call xTaskCheckForTimeout again as time could

-    		have passed since it was last called if this is not the

-    		first time around this loop. */

-			if( xTaskCheckForTimeOut( &xTimeOut, &xTicksToWait ) == pdFALSE )

+			if( prvIsQueueEmpty( pxQueue ) )

 			{

 				traceBLOCKING_ON_QUEUE_RECEIVE( pxQueue );

 

@@ -891,7 +909,9 @@ signed portCHAR *pcOriginalReadPosition;
 					if( pxQueue->uxQueueType == queueQUEUE_IS_MUTEX )

 					{

 						portENTER_CRITICAL();

+						{

 							vTaskPriorityInherit( ( void * ) pxQueue->pxMutexHolder );

+						}

 						portEXIT_CRITICAL();

 					}

 				}

@@ -906,15 +926,16 @@ signed portCHAR *pcOriginalReadPosition;
 			}

 			else

 			{

+				/* Try again. */

 				prvUnlockQueue( pxQueue );

 				( void ) xTaskResumeAll();

-				return errQUEUE_EMPTY;

 			}

 		}

 		else

 		{

 			prvUnlockQueue( pxQueue );

 			( void ) xTaskResumeAll();

+			return errQUEUE_EMPTY;

 		}

 	}

 }