static MQTTStatus_t addAwaitingOperation()

in source/core_mqtt_agent.c [308:372]
42 lines of code
7 McCabe index (conditional complexity)

static MQTTStatus_t addAwaitingOperation( MQTTAgentContext_t * pAgentContext,
                                          uint16_t packetId,
                                          MQTTAgentCommand_t * pCommand )
{
    size_t i = 0, unusedPos = MQTT_AGENT_MAX_OUTSTANDING_ACKS;
    MQTTStatus_t status = MQTTNoMemory;
    MQTTAgentAckInfo_t * pendingAcks = NULL;

    assert( pAgentContext != NULL );
    assert( pCommand != NULL );
    assert( packetId != MQTT_PACKET_ID_INVALID );
    pendingAcks = pAgentContext->pPendingAcks;

    /* Before adding the record for the pending acknowledgement of the packet ID,
     * make sure that there doesn't already exist an entry for the same packet ID.
     * Also, as part of iterating through the list of pending acknowledgements,
     * find an unused space for the packet ID to be added, if it can be. */
    for( i = 0; i < MQTT_AGENT_MAX_OUTSTANDING_ACKS; i++ )
    {
        /* If the packetId is MQTT_PACKET_ID_INVALID then the array space is not in
         * use. */
        if( ( unusedPos == MQTT_AGENT_MAX_OUTSTANDING_ACKS ) &&
            ( pendingAcks[ i ].packetId == MQTT_PACKET_ID_INVALID ) )
        {
            unusedPos = i;
            status = MQTTSuccess;
        }

        if( pendingAcks[ i ].packetId == packetId )
        {
            /* Check whether there exists a duplicate entry for pending
             * acknowledgment for the same packet ID that we want to add to
             * the list.
             * Note: This is an unlikely edge case which represents that a packet ID
             * didn't receive acknowledgment, but subsequent SUBSCRIBE/PUBLISH operations
             * representing 65535 packet IDs were successful that caused the bit packet
             * ID value to wrap around and reached the same packet ID as that was still
             * pending acknowledgment.
             */
            status = MQTTStateCollision;
            LogError( ( "Failed to add operation to list of pending acknowledgments: "
                        "Existing entry found for same packet: PacketId=%u\n", packetId ) );
            break;
        }
    }

    /* Add the packet ID to the list if there is space available, and there is no
     * duplicate entry for the same packet ID found. */
    if( status == MQTTSuccess )
    {
        pendingAcks[ unusedPos ].packetId = packetId;
        pendingAcks[ unusedPos ].pOriginalCommand = pCommand;
    }
    else if( status == MQTTNoMemory )
    {
        LogError( ( "Failed to add operation to list of pending acknowledgments: "
                    "No memory available: PacketId=%u\n", packetId ) );
    }
    else
    {
        /* Empty else MISRA 15.7 */
    }

    return status;
}