eventTest/eventTest.cpp

//-
// ==========================================================================
// Copyright 1995,2006,2008 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk
// license agreement provided at the time of installation or download,
// or which otherwise accompanies this software in either electronic
// or hard copy form.
// ==========================================================================
//+

// DESCRIPTION:
// 
// Produces the MEL command "eventTest".
//
// The eventTest plug-in is a simple plug-in that displays the "events" occurring in Maya.
// An event in Maya that occurs at a specific point in time is of interest to the Maya internals or plug-ins.
// For example, "SelectionChanged" and "timeChanged" are two events.
// These events can be tracked at the MEL level with the -event flag to the "scriptJob" command. 
//
// The plug-in adds an "eventTest" command that lets you know which events are available, track specific events,
// and know which events are being tracked. The basic command syntax is: 
//
//  eventTest [-m on|off] [eventName ...]
//
// The "eventName" arguments must be the names of events. If no names are specified, the command
// will operate on all available events.
//
// If you use the -m flag, you can specify whether the plug-in must track messages for the specified events.
// If you specify the -m flag without any event names, it will turn on or turn off tracking for all events.
// For example:
//
//  mel: eventTest -m 1 timeChanged
//  Event Name Msgs On
//  -------------------- -------
//  timeChanged yes
// 
// After this example, the plug-in will display the following each time when the current time changes:
//
//  event timeChanged occurred
//
// You can disable all event tracking with the command:
//
//  eventTest -m off; 
//

#include <stdio.h>

#include <maya/MIOStream.h>
#include <maya/MGlobal.h>
#include <maya/MString.h>
#include <maya/MStringArray.h>
#include <maya/MEventMessage.h>
#include <maya/MFnPlugin.h>

#include <maya/MPxCommand.h>
#include <maya/MSyntax.h>
#include <maya/MArgDatabase.h>

//
// Definitions
//

// Message flag
//
#define kMessageFlag        "m"
#define kMessageFlagLong    "message"

//
// Declarations
//

// Callback function for messages
//
static void eventCB(void * data);

// Array of callback ids.
//
typedef MCallbackId* MCallbackIdPtr;
static MCallbackIdPtr callbackId = NULL;

// Array of event names.
//
static MStringArray eventNames;

//
// Command class declaration
//
class eventTest : public MPxCommand
{
public:
    eventTest();
                    ~eventTest() override; 

    MStatus                 doIt( const MArgList& args ) override;

    static MSyntax          newSyntax();
    static void*            creator();

private:
    MStatus                 parseArgs( const MArgList& args );

    bool                    addMessage;
    bool                    delMessage;

    MStringArray            events;
};


//
// Command class implementation
//

// Constructor
//
eventTest::eventTest()
:   addMessage(false)
,   delMessage(false)
{
    events.clear();
}

// Destructor
//
eventTest::~eventTest()
{
    // Do nothing
}

// creator
//
void* eventTest::creator()
{
    return (void *) (new eventTest);
}

// newSyntax
//
MSyntax eventTest::newSyntax()
{
    MSyntax syntax;

    syntax.addFlag(kMessageFlag, kMessageFlagLong, MSyntax::kBoolean);
    syntax.setObjectType(MSyntax::kStringObjects);

    return syntax;
}

// parseArgs
//
MStatus eventTest::parseArgs(const MArgList& args)
{
    MStatus         status;
    MArgDatabase    argData(syntax(), args);

    if (argData.isFlagSet(kMessageFlag))
    {
        bool flag;

        status = argData.getFlagArgument(kMessageFlag, 0, flag);
        if (!status)
        {
            status.perror("could not parse message flag");
            return status;
        }

        if (flag)
        {
            addMessage = true;
        }
        else
        {
            delMessage = true;
        }
    }

    status = argData.getObjects(events);
    if (!status)
    {
        status.perror("could not parse event names");
    }

    // If there are no events specified, operate on all of them
    //
    if (events.length() == 0)
    {
        // eventNames is set in initializePlugin to all the
        // currently available event names.
        //
        events = eventNames;
    }

    return status;
}

// doIt
//
MStatus eventTest::doIt(const MArgList& args)
{
    MStatus status;

    status = parseArgs(args);
    if (!status)
    {
        return status;
    }

    // Allocate an array of indices.  events[n] is a user provided
    // event name.  Look it up in the static eventNames array
    // and set indices[n] to the index of the entry in eventNames.
    //
    // This maps the user specified events to the global events
    // so we can track callback adds and removes globally.
    //
    int * indices = new int [events.length()];

    int i, j;

    for (i = 0; i < (int)events.length(); ++i)
    {
        // Initialize the entry to "not found".
        //
        indices[i] = -1;

        // Search event names for a match.
        //
        for (j = 0; j < (int)eventNames.length(); ++j)
        {
            if (events[i] == eventNames[j])
            {
                // Found a match.  Store the index and stop looking for
                //
                indices[i] = j;
                break;
            }
        }
    }

    for (i = 0; i < (int)events.length(); ++i)
    {
        j = indices[i];
        if (j == -1)
        {
            MGlobal::displayWarning(events[i] +
                                    MString("is not a valid event name\n"));
            break;
        }

        if (addMessage && callbackId[j] == 0)
        {
            callbackId[j] = MEventMessage::addEventCallback(
                events[i],
                eventCB,
                (void *)(size_t)j,
                &status);
            
            if (!status)
            {
                status.perror("failed to add callback for " + events[i]);
                callbackId[j] = 0;
            }
        }
        else if (delMessage && callbackId[j] != 0)
        {
            status = MMessage::removeCallback(callbackId[j]);

            if (!status)
            {
                status.perror("failed to remove callback for " + events[i]);
            }

            callbackId[j] = 0;
        }
    }

    // Ok, we've made all the necessary changes.  Now show the status.
    //

    MGlobal::displayInfo("Event Name            Msgs On\n");
    MGlobal::displayInfo("--------------------  -------\n");

    char tmpStr[128];
    bool msgs;
    
    for (i = 0; i < (int)events.length(); ++i)
    {
        j = indices[i];
        if (j == -1)
        {
            continue;
        }

        msgs = (callbackId[j] != 0);

        sprintf(tmpStr, "%-20s  %s\n",
                events[i].asChar(),
                msgs  ? "yes"  : "no");

        MGlobal::displayInfo(tmpStr);
    }

    // Free up the indices we allocated.
    //
    delete [] indices;

    return status;
}

//
// Plug-in functions
//

MStatus initializePlugin( MObject obj )
{ 
    MStatus   status;
    MFnPlugin plugin( obj, PLUGIN_COMPANY, "3.0", "Any");

    status = MEventMessage::getEventNames(eventNames);
    if (!status)
    {
        return status;
    }

    // Search for and remove idle and idleHigh events since they will
    // completely swamp the output.  They are tested by the idleTest
    // plug-in
    //

    int i;

    for (i = 0; i < (int)eventNames.length(); ++i)
    {
        if (eventNames[i] == "idle" ||
            eventNames[i] == "idleHigh")
        {
            eventNames.remove(i);
            --i;
        }
    }
    
    cout<<"eventTest: "<<eventNames.length()<<" events are defined"<<endl;

    callbackId = new MCallbackId [eventNames.length()];

    if (!callbackId)
    {
        return MStatus(MS::kInsufficientMemory);
    }

    for (i = 0; i < (int)eventNames.length(); ++i)
    {
        callbackId[i] = 0;
    }

    // Register the command so we can actually do some work
    //
    status = plugin.registerCommand("eventTest",
                                    eventTest::creator,
                                    eventTest::newSyntax);

    if (!status)
    {
        status.perror("registerCommand");
    }

    return status;
}

MStatus uninitializePlugin( MObject obj)
{
    MStatus   status;
    MFnPlugin plugin( obj );

    // Loop through all the ids and remove the callbacks
    //
    int i;
    int len = eventNames.length();

    for (i = 0; i < len; ++i)
    {
        if (callbackId[i] != 0)
        {
            MGlobal::displayWarning("Removing callback for " +
                                    eventNames[i] +
                                    "\n");
            MMessage::removeCallback(callbackId[i]);
            callbackId[i] = 0;
        }
    }

    eventNames.clear();

    delete [] callbackId;

    // Deregister the command
    //
    status = plugin.deregisterCommand("eventTest");

    if (!status)
    {
        status.perror("deregisterCommand");
    }

    return status;
}

//
// Callback function
//

static void eventCB(void * data)
{
    int i = (int)(size_t)data;

    if (i >= 0 && i < (int)eventNames.length())
    {
        MGlobal::displayInfo("event " +
                             eventNames[i] +
                             " occurred\n");
    }
    else
    {
        MGlobal::displayWarning("BOGUS client data in eventCB!\n");
    }
}