len0rd/FreeRTOS-Kernel
1
0
Fork 0
mirror of https://github.com/FreeRTOS/FreeRTOS-Kernel.git synced 2025-04-19 21:11:57 -04:00
Code Issues Packages Projects Releases Wiki Activity

No functional changes. (#194)

Browse source 
Shorted overly verbose and opinionated comments in xStreamBufferSend().
Remove the unnecessary xIsFeasible variable from xStreamBufferSend().
This commit is contained in:
RichardBarry 2020-10-03 21:26:22 -07:00 committed by GitHub
parent b1307dbea8
commit fccb97b10b
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 11 additions and 35 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

46
stream_buffer.c
View file

@ -518,10 +518,6 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
size_t xRequiredSpace = xDataLengthBytes;
TimeOut_t xTimeOut;
/* Having a 'isFeasible' variable allows to respect the convention that there is only a return statement at the end. Othewise, return
* could be done as soon as we realise the send cannot happen. We will let the call to 'prvWriteMessageToBuffer' dealing with this scenario. */
BaseType_t xIsFeasible;
configASSERT( pvTxData );
configASSERT( pxStreamBuffer );
@ -536,55 +532,35 @@ size_t xStreamBufferSend( StreamBufferHandle_t xStreamBuffer,
/* Overflow? */
configASSERT( xRequiredSpace > xDataLengthBytes );
/* In the case of the message buffer, one has to be able to write the complete message as opposed to
* a stream buffer for semantic reasons. Check if it is physically possible to write the message given
* the length of the buffer. */
/* If this is a message buffer then it must be possible to write the
* whole message. */
if( xRequiredSpace > pxStreamBuffer->xLength )
{
/* The message could never be written because it is greater than the buffer length.
* By setting xIsFeasable to FALSE, we skip over the following do..while loop, thus avoiding
* a deadlock. The call to 'prvWriteMessageToBuffer' toward the end of this function with
* xRequiredSpace greater than xSpace will suffice in not writing anything to the internal buffer.
* Now, the function will return 0 because the message could not be written. Should an error code be
* returned instead ??? In my opinion, probably.. But the return type doesn't allow for negative
* values to be returned. A confusion could exist to the caller. Returning 0 because a timeout occurred
* and a subsequent send attempts could eventually succeed, and returning 0 because a write could never
* happen because of the size are two scenarios to me :/ */
xIsFeasible = pdFALSE;
/* The message would not fit even if the entire buffer was empty,
* so don't wait for space. */
xTicksToWait = ( TickType_t ) 0;
}
else
{
/* It is possible to write the message completely in the buffer. This is the intended route.
* Let's continue with the regular timeout logic. */
xIsFeasible = pdTRUE;
mtCOVERAGE_TEST_MARKER();
}
}
else
{
/* In the case of the stream buffer, not being able to completely write the message in the buffer
* is an acceptable scenario, but it has to be dealt with properly */
/* If this is a stream buffer then it is acceptable to write only part
* of the message to the buffer. Cap the length to the total length of
* the buffer. */
if( xRequiredSpace > pxStreamBuffer->xLength )
{
/* Not enough buffer space. We will attempt to write as much as we can in this run
* so that the caller can send the remaining in subsequent calls. We avoid a deadlock by
* offering the possibility to take the 'else' branch in the 'if( xSpace < xRequiredSpace )'
* condition inside the following do..while loop */
xRequiredSpace = pxStreamBuffer->xLength;
/* TODO FIXME: Is there a check we should do with the xTriggerLevelBytes value ? */
/* With the adjustment to 'xRequiredSpace', the deadlock is avoided, thus it's now feasible. */
xIsFeasible = pdTRUE;
}
else
{
/* It is possible to write the message completely in the buffer. */
xIsFeasible = pdTRUE;
mtCOVERAGE_TEST_MARKER();
}
}
/* Added check against xIsFeasible. If it's not feasible, don't even wait for notification, let the call to 'prvWriteMessageToBuffer' do nothing and return 0 */
if( ( xTicksToWait != ( TickType_t ) 0 ) && ( xIsFeasible == pdTRUE ) )
if( xTicksToWait != ( TickType_t ) 0 )
{
vTaskSetTimeOutState( &xTimeOut );