/**************************************************************************/
/*                                                                        */
/*       Copyright (c) Microsoft Corporation. All rights reserved.        */
/*                                                                        */
/*       This software is licensed under the Microsoft Software License   */
/*       Terms for Microsoft Azure RTOS. Full text of the license can be  */
/*       found in the LICENSE file at https://aka.ms/AzureRTOS_EULA       */
/*       and in the root directory of this software.                      */
/*                                                                        */
/**************************************************************************/


/**************************************************************************/
/**************************************************************************/
/**                                                                       */
/** ThreadX Component                                                     */
/**                                                                       */
/**   Event Flags                                                         */
/**                                                                       */
/**************************************************************************/
/**************************************************************************/

#define TX_SOURCE_CODE


/* Include necessary system files.  */

#include "tx_api.h"
#include "tx_thread.h"
#include "tx_event_flags.h"


/**************************************************************************/
/*                                                                        */
/*  FUNCTION                                               RELEASE        */
/*                                                                        */
/*    _tx_event_flags_cleanup                             PORTABLE C      */
/*                                                           6.0          */
/*  AUTHOR                                                                */
/*                                                                        */
/*    William E. Lamie, Microsoft Corporation                             */
/*                                                                        */
/*  DESCRIPTION                                                           */
/*                                                                        */
/*    This function processes event flags timeout and thread terminate    */
/*    actions that require the event flags data structures to be cleaned  */
/*    up.                                                                 */
/*                                                                        */
/*  INPUT                                                                 */
/*                                                                        */
/*    thread_ptr                        Pointer to suspended thread's     */
/*                                        control block                   */
/*                                                                        */
/*  OUTPUT                                                                */
/*                                                                        */
/*    None                                                                */
/*                                                                        */
/*  CALLS                                                                 */
/*                                                                        */
/*    _tx_thread_system_resume          Resume thread service             */
/*    _tx_thread_system_ni_resume       Non-interruptable resume thread   */
/*                                                                        */
/*  CALLED BY                                                             */
/*                                                                        */
/*    _tx_thread_timeout                Thread timeout processing         */
/*    _tx_thread_terminate              Thread terminate processing       */
/*    _tx_thread_wait_abort             Thread wait abort processing      */
/*                                                                        */
/*  RELEASE HISTORY                                                       */
/*                                                                        */
/*    DATE              NAME                      DESCRIPTION             */
/*                                                                        */
/*  05-19-2020     William E. Lamie         Initial Version 6.0           */
/*                                                                        */
/**************************************************************************/
VOID  _tx_event_flags_cleanup(TX_THREAD  *thread_ptr, ULONG suspension_sequence)
{

#ifndef TX_NOT_INTERRUPTABLE
TX_INTERRUPT_SAVE_AREA
#endif

TX_EVENT_FLAGS_GROUP        *group_ptr;
UINT                        suspended_count;
TX_THREAD                   *suspension_head;
TX_THREAD                   *next_thread;
TX_THREAD                   *previous_thread;


#ifndef TX_NOT_INTERRUPTABLE

    /* Disable interrupts to remove the suspended thread from the event flags group.  */
    TX_DISABLE

    /* Determine if the cleanup is still required.  */
    if (thread_ptr -> tx_thread_suspend_cleanup == &(_tx_event_flags_cleanup))
    {

        /* Check for valid suspension sequence.  */
        if (suspension_sequence == thread_ptr -> tx_thread_suspension_sequence)
        {

            /* Setup pointer to event flags control block.  */
            group_ptr =  TX_VOID_TO_EVENT_FLAGS_POINTER_CONVERT(thread_ptr -> tx_thread_suspend_control_block);
    
            /* Check for a NULL event flags control block pointer.  */
            if (group_ptr != TX_NULL)
            {
                
                /* Is the group pointer ID valid?  */
                if (group_ptr -> tx_event_flags_group_id == TX_EVENT_FLAGS_ID)
                {

                    /* Determine if there are any thread suspensions.  */
                    if (group_ptr -> tx_event_flags_group_suspended_count != TX_NO_SUSPENSIONS)
                    {
#else

                        /* Setup pointer to event flags control block.  */
                        group_ptr =  TX_VOID_TO_EVENT_FLAGS_POINTER_CONVERT(thread_ptr -> tx_thread_suspend_control_block);
#endif

                        /* Yes, we still have thread suspension!  */

                        /* Clear the suspension cleanup flag.  */
                        thread_ptr -> tx_thread_suspend_cleanup =  TX_NULL;

                        /* Pickup the suspended count.  */
                        suspended_count =  group_ptr -> tx_event_flags_group_suspended_count;

                        /* Pickup the suspension head.  */
                        suspension_head =  group_ptr -> tx_event_flags_group_suspension_list;

                        /* Determine if the cleanup is being done while a set operation was interrupted.  If the 
                           suspended count is non-zero and the suspension head is NULL, the list is being processed
                           and cannot be touched from here. The suspension list removal will instead take place 
                           inside the event flag set code.  */
                        if (suspension_head != TX_NULL)
                        {

                            /* Remove the suspended thread from the list.  */

                            /* Decrement the local suspension count.  */
                            suspended_count--;
              
                            /* Store the updated suspended count.  */
                            group_ptr -> tx_event_flags_group_suspended_count =  suspended_count;

                            /* See if this is the only suspended thread on the list.  */
                            if (suspended_count == TX_NO_SUSPENSIONS)
                            {

                                /* Yes, the only suspended thread.  */
        
                                /* Update the head pointer.  */
                                group_ptr -> tx_event_flags_group_suspension_list =  TX_NULL;
                            }
                            else
                            {

                                /* At least one more thread is on the same suspension list.  */
    
                                /* Update the links of the adjacent threads.  */
                                next_thread =                                  thread_ptr -> tx_thread_suspended_next;
                                previous_thread =                              thread_ptr -> tx_thread_suspended_previous;
                                next_thread -> tx_thread_suspended_previous =  previous_thread;
                                previous_thread -> tx_thread_suspended_next =  next_thread;
                
                                /* Determine if we need to update the head pointer.  */
                                if (suspension_head == thread_ptr)
                                {
                
                                    /* Update the list head pointer.  */
                                    group_ptr -> tx_event_flags_group_suspension_list =  next_thread;
                                }
                            }
                        }
                        else
                        {
                        
                            /* In this case, the search pointer in an interrupted event flag set must be reset.  */
                            group_ptr -> tx_event_flags_group_reset_search =  TX_TRUE;
                        }

                        /* Now we need to determine if this cleanup is from a terminate, timeout,
                           or from a wait abort.  */
                        if (thread_ptr -> tx_thread_state == TX_EVENT_FLAG)
                        {

                            /* Timeout condition and the thread still suspended on the event flags group.  
                               Setup return error status and resume the thread.  */

#ifdef TX_EVENT_FLAGS_ENABLE_PERFORMANCE_INFO

                            /* Increment the total timeouts counter.  */
                            _tx_event_flags_performance_timeout_count++;

                            /* Increment the number of timeouts on this event flags group.  */
                            group_ptr -> tx_event_flags_group____performance_timeout_count++;
#endif

                            /* Setup return status.  */
                            thread_ptr -> tx_thread_suspend_status =  TX_NO_EVENTS;

#ifdef TX_NOT_INTERRUPTABLE

                            /* Resume the thread!  */
                            _tx_thread_system_ni_resume(thread_ptr);
#else

                           /* Temporarily disable preemption.  */
                            _tx_thread_preempt_disable++;

                            /* Restore interrupts.  */
                            TX_RESTORE

                            /* Resume the thread!  Check for preemption even though we are executing 
                               from the system timer thread right now which normally executes at the 
                               highest priority.  */
                            _tx_thread_system_resume(thread_ptr);

                            /* Disable interrupts.  */
                            TX_DISABLE
#endif
                        }
#ifndef TX_NOT_INTERRUPTABLE
                    }
                }
            }
        }
    }

    /* Restore interrupts.  */
    TX_RESTORE
#endif
}

