/*

    File:       MoreBlueActions.c

    Contains:   Library for efficiently scheduling deferred task actions

                from MP tasks.

    Written by: Quinn

    Copyright:  Copyright © 2000 by Apple Computer, Inc., All Rights Reserved.

    Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.

                ("Apple") in consideration of your agreement to the following terms, and your

                use, installation, modification or redistribution of this Apple software

                constitutes acceptance of these terms.  If you do not agree with these terms,

                please do not use, install, modify or redistribute this Apple software.

                In consideration of your agreement to abide by the following terms, and subject

                to these terms, Apple grants you a personal, non-exclusive license, under AppleÕs

                copyrights in this original Apple software (the "Apple Software"), to use,

                reproduce, modify and redistribute the Apple Software, with or without

                modifications, in source and/or binary forms; provided that if you redistribute

                the Apple Software in its entirety and without modifications, you must retain

                this notice and the following text and disclaimers in all such redistributions of

                the Apple Software.  Neither the name, trademarks, service marks or logos of

                Apple Computer, Inc. may be used to endorse or promote products derived from the

                Apple Software without specific prior written permission from Apple.  Except as

                expressly stated in this notice, no other rights or licenses, express or implied,

                are granted by Apple herein, including but not limited to any patent rights that

                may be infringed by your derivative works or by other works in which the Apple

                Software may be incorporated.

                The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO

                WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED

                WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR

                PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN

                COMBINATION WITH YOUR PRODUCTS.

                IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR

                CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE

                GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

                ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION

                OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT

                (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN

                ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

    Change History (most recent first):

         <4>     21/9/01    Quinn   Changes for CWPro7 Mach-O build.

         <3>    22/11/00    Quinn   Don't allow classic 68K builds for the reasons explained in the

                                    comments.

         <2>    10/11/00    Quinn   Added more MPLog points. I used this to help track down a

                                    CarbonLib bug, but they are generally useful so I thought I'd

                                    keep them around.

         <1>     7/11/00    Quinn   First checked in.

*/

/////////////////////////////////////////////////////////////////

// MoreIsBetter Setup

#include "MoreSetup.h"

// Mac OS Interfaces

#if ! MORE_FRAMEWORK_INCLUDES

    #include <OSUtils.h>

    #include <Multiprocessing.h>

#endif

// MIB interfaces

#include "MoreMPLog.h"

// Our prototypes

#include "MoreBlueActions.h"

/////////////////////////////////////////////////////////////////

static pascal void MoreBlueActionsRun(long dtParam);        // Forward declare to allow globals to be grouped before code.

static OTLIFO gMoreBlueActionList = {nil};              // List of MoreBlueAction's chained through link.

// I want to statically allocate my RoutineDescriptor (because it avoids 

// possible memory allocation failures) but Carbon won't let me do that.

// *sigh*

// 

// gMoreBlueActionsRun is the single deferred task that is used to run all 

// of our Blue actions.  The MoreBlueActionInstall routine allocates it by using

// an atomic test and set on gMoreBlueActionsRunInUse.

#if TARGET_API_MAC_CARBON

    static DeferredTask gMoreBlueActionsRun = {nil, dtQType, 0, nil, 0, 0};

#else

    static RoutineDescriptor gMoreBlueActionsRunRD = BUILD_ROUTINE_DESCRIPTOR(uppDeferredTaskProcInfo, MoreBlueActionsRun);

    // We canÕt use this module for classic 68K code because &gMoreBlueActionsRunRD 

    // is not a valid UPP for the 68K build.  I originally tried to work around this 

    // by conditionally declaring this structure to use MoreBlueActionsRun for 

    // the 68K case.  However, this doesn't really work properly because the 

    // callback has to use register calling conventions.  I could fix this with 

    // enough messing around with "#pragma parameter" and :__d0, but I decided 

    // it wasnÕt worth the effort because this module is specifically targetted 

    // for MP code, and you canÕt run 68K code in an MP task.

    #if !TARGET_RT_MAC_CFM

        #error This module can not be used by 68K code.

    #endif

    static DeferredTask gMoreBlueActionsRun = {nil, dtQType, 0, &gMoreBlueActionsRunRD, 0, 0};

#endif

static OTLock gMoreBlueActionsRunInUse = 0; // Set if gMoreBlueActionsRun is currently in the

                                            // deferred task queue.

// This global controls whether blue actions are run at deferred task time 

// or system task time.  See the header file comments for a discussion of 

// this facility.

#if MORE_DEBUG

    static Boolean gRunAsSystemTasks = false;

    static Boolean gModuleInitialised;

#endif

extern pascal OSStatus InitMoreBlueActions(void)

    // See comment in header file.

{

    OSStatus err;

    MoreAssertQ( ! MPTaskIsPreemptive(kInvalidID) );

    MoreAssertQ( ! gModuleInitialised );

    err = noErr;

    #if TARGET_API_MAC_CARBON

        // Carbon makes me do this silliness!

        gMoreBlueActionsRun.dtAddr = NewDeferredTaskUPP(MoreBlueActionsRun);

        if (gMoreBlueActionsRun.dtAddr == nil) {

            err = memFullErr;

        }

    #endif

    #if MORE_DEBUG

        gModuleInitialised = (err == noErr);

    #endif

    return err;

}

extern pascal void     TermMoreBlueActions(void)

    // See comment in header file.

{

    MoreAssertQ( ! MPTaskIsPreemptive(kInvalidID) );

    MoreAssertQ( gModuleInitialised );

    #if TARGET_API_MAC_CARBON

        if (gMoreBlueActionsRun.dtAddr != nil) {

            DisposeDeferredTaskUPP(gMoreBlueActionsRun.dtAddr);

            gMoreBlueActionsRun.dtAddr = nil;

        }

    #endif

    #if MORE_DEBUG

        gModuleInitialised = false;

    #endif

}

static pascal void MoreBlueActionsRun(long dtParam)

    // This routine is run in two possible ways.  If blue actions 

    // are being run as deferred tasks (which typically is true), 

    // this routine is called by the Deferred Task Manager.

    // If blue actions are being run as system tasks (during debugging),

    // this routine is run by MoreBTRunNow, which is called by the client

    // at system task time.

    //

    // Regardless of how it's call, the routine does the same thing.

    // It first clears gMoreBlueActionsRunInUse, which ensures that any 

    // future blue actions being installed will schedule the deferred task 

    // again.  It then grabs the list of blue actions and runs them one 

    // at a time.

{

    OTLink *taskList;

    MPLog(kMoreBlueActionsLogID, '>Blu');

    #pragma unused(dtParam)

    OTClearLock(&gMoreBlueActionsRunInUse);

    taskList = OTReverseList(OTLIFOStealList(&gMoreBlueActionList));

    while ( taskList != nil ) {

        MoreBlueAction *thisTask;

        thisTask = OTGetLinkObject(taskList, MoreBlueAction, link);

        MoreAssertQ(thisTask->magic == kMoreBlueActionMagic);

        // Move taskList along to next element before calling action proc

        // so that action proc can 'dispose' of thisTask in some way.

        taskList = taskList->fNext;

        MoreAssertQ(thisTask->action != nil);

        MPLog1(kMoreBlueActionsLogID, 'BluD', thisTask);

        (thisTask->action)(thisTask);

    }

    MPLog(kMoreBlueActionsLogID, '<Blu');

}

extern pascal void MoreBlueActionInstall(MoreBlueAction *thisTask)

    // See comment in header file.

{

    OSStatus junk;

    MoreAssertQ(thisTask->magic  == kMoreBlueActionMagic);

    MoreAssertQ(thisTask->action != nil);

    MoreAssertQ( gModuleInitialised );

    MPLog1(kMoreBlueActionsLogID, '>BlQ', thisTask);

    // First put the task on the list of tasks to run.  Then 

    // see whether the deferred task is already installed or not. 

    // If it isn't, install it.  If it is, just return.  The 

    // deferred task will handle /all/ of the requests on the list.

    OTLIFOEnqueue(&gMoreBlueActionList, &thisTask->link);

    if ( OTAcquireLock(&gMoreBlueActionsRunInUse) ) {

        #if MORE_DEBUG

            if (gRunAsSystemTasks) {

                // Blue actions will be run when client calls MoreBlueActionsRunNow.

                MPLog1(kMoreBlueActionsLogID, 'BlQ1', thisTask);

                junk = noErr;

            } else {

                MPLog1(kMoreBlueActionsLogID, 'BlQ2', thisTask);

                junk = DTInstall(&gMoreBlueActionsRun);

            }

        #else

            junk = DTInstall(&gMoreBlueActionsRun);

        #endif

        MoreAssertQ(junk == noErr);

    } else {

        MPLog1(kMoreBlueActionsLogID, 'BlQ3', thisTask);

    }

    MPLog(kMoreBlueActionsLogID, '<BlQ');

}

#if MORE_DEBUG

    extern pascal void MoreBTRunAsSystemTasks(Boolean asSystemTasks)

        // See comment in header file.

    {

        MoreAssertQ( ! MPTaskIsPreemptive(kInvalidID) );

        gRunAsSystemTasks = asSystemTasks;

    }

    extern pascal void MoreBTRunNow(void)

        // See comment in header file.

    {

        MoreAssertQ( ! MPTaskIsPreemptive(kInvalidID) );

        if ( gMoreBlueActionsRunInUse ) {

            MoreBlueActionsRun(0);

        }

    }

#endif