HID_Transaction_Utilities.c

/*
    File:       HID_Transaction_Utilities.h
 
    Contains:   Definitions of the HID queue functions for the HID utilites.
    
    DRI: George Warner
 
    Copyright:  Copyright © 2002 Apple Computer, Inc., All Rights Reserved
 
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*/
 
#include <CoreServices/CoreServices.h>
 
#include "HID_Utilities_Internal.h"
#include "HID_Utilities_External.h"
 
// ==================================
// private functions
 
// creates a transaction for a device, allocates and creates the transaction interface if required
 
static IOReturn hid_CreateTransaction(pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
 
    if (HIDIsValidDevice(pDevice))
    {
        if (NULL == pDevice->transaction) // if we don't already have a transactionÉ
        {
            if (NULL != pDevice->interface) // and we do have an interfaceÉ
            {
                pDevice->transaction = (void *) (*(IOHIDDeviceInterface**) pDevice->interface)->allocOutputTransaction (pDevice->interface); // alloc Transaction
                if (pDevice->transaction)   // if it was successfulÉ
                {
                    result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->create (pDevice->transaction); // create actual transaction
                    if (kIOReturnSuccess != result)
                        HIDReportErrorNum ("\nFailed to create transaction via create: error = %ld.", result);
                }
                else
                {
                    HIDReportError ("\nhid_CreateTransaction failed to allocOutputTransaction");
                    if (!result)
                        result = kIOReturnError; // synthesis error
                }
            }
            else
                HIDReportErrorNum ("\nhid_CreateTransaction failed: Device inteface does not exist.", result);
        }
    }
    return result;
}
 
// ==================================
// public functions
// ---------------------------------
// add an element to a Transaction
unsigned long HIDTransactionAddElement(pRecDevice pDevice, pRecElement pElement)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->addElement (pDevice->transaction,pElement->cookie); // add element
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionAddElement failed to add Element: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionAddElement failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}
 
// removes an element from a Transaction
unsigned long HIDTransactionRemoveElement(pRecDevice pDevice, pRecElement pElement)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->removeElement (pDevice->transaction,pElement->cookie); // remove element
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionRemoveElement failed to remove Element: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionRemoveElement failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
 
    return result;
}
 
// return true if this transaction contains this element
Boolean HIDTransactionHasElement(pRecDevice pDevice, pRecElement pElement)
{
    Boolean result = false;
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        (void) hid_CreateTransaction(pDevice);
 
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->hasElement (pDevice->transaction,pElement->cookie); // remove element
        }
        else
        {
            HIDReportError ("\nHIDTransactionHasElement failed: no transaction interface");
        }
    }
    return result;
}
 
/* This changes the default value of an element, when the values of the */
/* elements are cleared, on clear or commit, they are reset to the */
/* default value */
/* This call can be made on elements that are not in the transaction, but */
/* has undefined behavior if made on elements not in the transaction */
/* which are later added to the transaction. */
/* In other words, an element should be added before its default is */
/* set, for well defined behavior. */
unsigned long HIDTransactionSetElementDefault(pRecDevice pDevice, pRecElement pElement,IOHIDEventStruct* pValueEvent)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->setElementDefault (pDevice->transaction,pElement->cookie, pValueEvent);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionSetElementDefault failed to set Element Default: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionSetElementDefault failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
 
    return result;
}
 
/* Get the current setting of an element's default value */
unsigned long HIDTransactionGetElementDefault(pRecDevice pDevice, pRecElement pElement,IOHIDEventStruct* pValueEvent)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->getElementDefault (pDevice->transaction,pElement->cookie, pValueEvent);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionGetElementDefault failed to get Element Default: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionGetElementDefault failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}
 
/* Add a change to the transaction, by setting an element value */
/* The change is not actually made until it is commited */
/* The element must be part of the transaction or this call will fail */
unsigned long HIDTransactionSetElementValue(pRecDevice pDevice, pRecElement pElement,IOHIDEventStruct* pValueEvent)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->setElementValue (pDevice->transaction,pElement->cookie, pValueEvent);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionSetElementValue failed to set Element Default: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionSetElementValue failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}
 
/* Get the current setting of an element value */
unsigned long HIDTransactionGetElementValue(pRecDevice pDevice, pRecElement pElement,IOHIDEventStruct* pValueEvent)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidElement(pDevice,pElement))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->getElementValue (pDevice->transaction,pElement->cookie, pValueEvent);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionGetElementValue failed to get Element Default: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionGetElementValue failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}
 
/* Commit the transaction, or clear all the changes and start over */
unsigned long HIDTransactionCommit(pRecDevice pDevice)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidDevice(pDevice))
    {
        if (pDevice->transaction)
        {
#if 0000
            // NOTE: this code is to workaround a bug where if you commit transactions
            // too fast then some of the reports get dropped.
            // (fixed in 10.2.1)
            static AbsoluteTime nextTime = {0,0};   // first time this should be no delay
 
            if (nextTime.hi || nextTime.lo)
                MPDelayUntil(&nextTime);
#endif
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->commit (pDevice->transaction,-1,NULL,NULL,NULL);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionCommit failed to commit: error = %ld.", result);
#if 0000
            nextTime = AddDurationToAbsolute(20 * kDurationMillisecond,UpTime());
#endif
        }
        else
        {
            HIDReportError ("\nHIDTransactionCommit failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}
 
/* Clear all the changes and start over */
unsigned long HIDTransactionClear(pRecDevice pDevice)
{
    IOReturn result = hid_CreateTransaction(pDevice);
 
    if (HIDIsValidDevice(pDevice))
    {
        if (pDevice->transaction)
        {
            result = (*(IOHIDOutputTransactionInterface**) pDevice->transaction)->clear (pDevice->transaction);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("\nHIDTransactionClear failed to get Element Default: error = %ld.", result);
        }
        else
        {
            HIDReportError ("\nHIDTransactionClear failed: no transaction interface");
            if (!result)
                result = kIOReturnError; // synthesis error
        }
    }
    return result;
}


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