Allow passing of custom context to tx_*_notify

[alobop]

I’m working with threadx and I wanted to use the event chaining for one of my applications. I noticed that it is not possible to pass down a private context for the callback (unlike other functions that allow arbitrary user context such as the thread_create, timer_create). Since this is not possible, it forces the callee to have a static context for modules that use the event chaining feature.

struct DRIVER_X
{
    TX_THREAD WorkingThread;
    TX_SEMAPHORE ThreadWakeup;

    TX_EVENT_FLAGS_GROUP InterruptStatus;
    TX_QUEUE UserRequests;
};

DRIVER_X instanceA;
DRIVER_X instanceB;

InitDriverX(&instanceA);
InitDriverX(&instanceB);

....

void InitDriverX(DRIVER_X* driver)
{
    tx_thread_create(driver->WorkingThread, "WorkingThread", driver, ....);
    tx_semaphore_create(driver->ThreadWakeup, "Wakeup", 0);
    tx_event_flags_create(driver->InterruptStatus, "Status");
    tx_queue_create(driver->UserRequests, "Reqs", ...);

    /* Chain flag and queue into the semaphore */
    tx_queue_send_notify(..., QueueNotify);
    tx_event_flag_set_notify(..., FlagNotify);
}

static void QueueNotify(TX_QUEUE* pQueue)
{
    // How to differentiate between a call for instanceA vs instanceB?
    tx_semaphore_put(??????);
} 

static void FlagNotify(TX_EVENT_FLAGS_GROUP* pQueue)
{
    // How to differentiate between a call for instanceA vs instanceB?
    tx_semaphore_put(??????);
}

vs

struct DRIVER_X
{
    TX_THREAD WorkingThread;
    TX_SEMAPHORE ThreadWakeup;

    TX_EVENT_FLAGS_GROUP InterruptStatus;
    TX_QUEUE UserRequests;
};

DRIVER_X instanceA;
DRIVER_X instanceB;

InitDriverX(&instanceA);
InitDriverX(&instanceB);

....

void InitDriverX(DRIVER_X* driver)
{
    tx_thread_create(driver->WorkingThread, "WorkingThread", driver, ....);
    tx_semaphore_create(driver->ThreadWakeup, "Wakeup", 0);
    tx_event_flags_create(driver->InterruptStatus, "Status");
    tx_queue_create(driver->UserRequests, "Reqs", ...);

    /* Chain flag and queue into the semaphore */
    tx_queue_send_notify(..., QueueNotify, driver);
    tx_event_flag_set_notify(..., FlagNotify, driver);
}

static void QueueNotify(TX_QUEUE* pQueue, void* pContext)
{
    DRIVER_X* pDriver = pContext;
    tx_semaphore_put(pDriver->ThreadWakeup);
} 

static void FlagNotify(TX_EVENT_FLAGS_GROUP* pQueue, void* pContext)
{
    DRIVER_X* pDriver = pContext;
    tx_semaphore_put(pDriver->ThreadWakeup);
}

[goldscott]

Yeah, you're right, there's no good way to pass custom context.

One possibility is to use the extension members of the structs to store custom context, e.g. you can define the TX_QUEUE_EXTENSION member of the queue struct: https://github.com/azure-rtos/threadx/blob/master/common/inc/tx_api.h#L939

[goldscott]

Closing. Anyone feel free to re-open if there are further questions related to this.