dagMessageCmd/dagMessageCmd.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.
// ==========================================================================
//+

//
// dagMessageCmd.cpp
//
// Description:
//     Sample plug-in that demonstrates how to register/de-register
//     a callback with the MDagMessage class.
//
//     This plug-in will register a new command in maya called
//     "dagMessage" which adds a callback for the all nodes on
//     the active selection list. A message is printed to stdout 
//     whenever a connection is made or broken for those nodes. If
//      nothing is selected, the callback will be for all nodes.
//
//     dagMessage -help will list the options.
//
#include <maya/MIOStream.h>
#include <maya/MPxCommand.h>
#include <maya/MFnPlugin.h>
#include <maya/MArgList.h>
#include <maya/MArgDatabase.h>
#include <maya/MIntArray.h>
#include <maya/MSelectionList.h>
#include <maya/MGlobal.h>
#include <maya/MPlug.h>
#include <maya/MSyntax.h>
#include <maya/MDagMessage.h>
#include <maya/MDGMessage.h>
#include <maya/MModelMessage.h>
#include <maya/MDagPath.h>
#include <maya/MFnDagNode.h>
#include <maya/MCallbackIdArray.h>
#include <maya/MObjectArray.h>

#define kCmdName                    "dagMessage"

#define kAllDagFlag                 "-ad"
#define kAllDagFlagLong             "-allDag"
#define kParentAddedFlag            "-pa"
#define kParentAddedFlagLong        "-parentAdded"
#define kParentRemovedFlag          "-pr"
#define kParentRemovedFlagLong      "-parentRemoved"
#define kChildAddedFlag             "-ca"
#define kChildAddedFlagLong         "-childAdded"
#define kChildRemovedFlag           "-cr"
#define kChildRemovedFlagLong       "-childRemoved"
#define kChildReorderedFlag         "-cro"
#define kChildReorderedFlagLong     "-childReordered"

#define kHelpFlag                   "-h"
#define kHelpFlagLong               "-help"

#define CheckErrorContinue(stat, msg)   \
    if (MS::kSuccess != stat) {         \
        displayError(msg);              \
        continue;                       \
    }                           

#define CheckErrorReturn(stat, msg)     \
    if (MS::kSuccess != stat) {         \
        displayError(msg);              \
        return;                         \
    }

// This table will keep track of the registered callbacks
// so they can be removed when the plug-ins is unloaded.
//
MCallbackIdArray callbackIds;

// Node added to model callback.
static void userNodeRemovedCB(MObject& node,void *clientData)
{
    if (! node.isNull()) {
        bool doDisplay = true;

        MStatus status;
        MFnDagNode dagNode(node,&status);
        if ( status.error() ) {
            doDisplay = false;
            MGlobal::displayInfo("Error: failed to get dag node.");
        }

        if ( doDisplay ) {
            MString s = dagNode.name();
            MString info("DAG Model -  Node removed: ");
            info+= s;

            MGlobal::displayInfo(info); 
        }
    }

    // remove the callback
    MCallbackId id = MMessage::currentCallbackId();
    MMessage::removeCallback(id);
}

// Node added to model callback.
static void userNodeAddedCB(MObject& node,void *clientData)
{
    MStatus status;

    if (! node.isNull()) {
        bool doDisplay = true;

        MDagPath path;
        status = MDagPath::getAPathTo(node,path);
        if ( status.error() ) {
            doDisplay = false;
            MGlobal::displayInfo("Error: failed to get dag path to node.");
        }

        if ( doDisplay ) {
            MString s = path.fullPathName();
            MString info("DAG Model -  Node added: ");
            info+= s;

            path.transform(&status);
            if (MS::kInvalidParameter == status) {
                info += "(WORLD)";
            }

            MGlobal::displayInfo(info); 
        }
    }

    // remove the callback
    MCallbackId id = MMessage::currentCallbackId();
    MMessage::removeCallback(id);

    // listen for removal message
    /* MCallbackId id = */ MModelMessage::addNodeRemovedFromModelCallback( node, userNodeRemovedCB, 0, &status );
    if ( status.error() ) {
        MGlobal::displayError("Failed to install node removed from model callback.\n");
        return;
    }
}

// Install a node added callback for the node specified
// by dagPath.
static void installNodeAddedCallback( MDagPath& dagPath )
{
    MStatus status;

    MObject dagNode = dagPath.node();
    if ( dagNode.isNull() )
        return;

    /* MCallbackId id = */ MModelMessage::addNodeAddedToModelCallback( dagNode, userNodeAddedCB, 0, &status );
    if ( status.error() ) {
        MGlobal::displayError("Failed to install node added to model callback.\n");
        return;
    }
}

// Decide if the dag is in the model. Dag paths and names
// may not be setup if the dag has not been added to
// the model.
static bool dagNotInModel( MDagPath& dagPath )
{
    MStatus status;
    MFnDagNode dagFn( dagPath, &status );
    if ( status.error() )
        return false;
    bool inModel = dagFn.inModel( &status );
    if ( status.error() )
        return false;
    return ( inModel == false );
}

void userDAGGenericCB(MDagMessage::DagMessage msg, MDagPath &child,
                      MDagPath &parent, void *)
{   
    MString dagStr("DAG Changed - ");
    switch (msg) {
        case MDagMessage::kParentAdded:
            dagStr += "Parent Added: ";
            break;
        case MDagMessage::kParentRemoved:
            dagStr += "Parent Removed: ";
            break;
        case MDagMessage::kChildAdded:
            dagStr += "Child Added: ";
            break;
        case MDagMessage::kChildRemoved:
            dagStr += "Child Removed: ";
            break;
        case MDagMessage::kChildReordered:
            dagStr += "Child Reordered: ";
            break;
        default:
            dagStr += "Unknown Type: ";
            break;
    }

    dagStr += "child = ";
    dagStr += child.fullPathName();
    dagStr += ", parent = ";
    dagStr += parent.fullPathName();

    // Check to see if the parent is the world object.
    //
    MStatus pStat;
    parent.transform(&pStat);
    if (MS::kInvalidParameter == pStat) {
        dagStr += "(WORLD)";
    }

    // Install callbacks if node is not in the model.
    // Callback is for node added to model.
    bool incomplete = false;
    if ( dagNotInModel( child ) ) {
        installNodeAddedCallback( child );
        incomplete = true;
    }
    if ( dagNotInModel( parent ) ) {
        installNodeAddedCallback( parent);
        incomplete = true;
    }

    // Warn user that dag path info may be
    // incomplete
    if (incomplete)
        dagStr += "\t// May be incomplete!";    

    MGlobal::displayInfo(dagStr);
}


//
// Command class declaration
//

class dagMessageCmd : public MPxCommand
{
public:
                    dagMessageCmd() {};
                ~dagMessageCmd() override; 
    MStatus         doIt( const MArgList& args ) override;

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

private:

    MStatus         addGenericCallback(MDagPath *dagPath, 
                                       MDagMessage::DagMessage msg, 
                                       MString cbName); 
};

//
// Command class implementation
//

dagMessageCmd::~dagMessageCmd() {}

void* dagMessageCmd::creator()
{
    return new dagMessageCmd();
}

MSyntax dagMessageCmd::newSyntax()
{
    MSyntax syntax;

    syntax.useSelectionAsDefault(true);
    syntax.setObjectType(MSyntax::kSelectionList);
    syntax.setMinObjects(0);

    syntax.addFlag(kAllDagFlag, kAllDagFlagLong);
    syntax.addFlag(kParentAddedFlag, kParentAddedFlagLong);
    syntax.addFlag(kParentRemovedFlag, kParentRemovedFlagLong);
    syntax.addFlag(kChildAddedFlag, kChildAddedFlagLong);
    syntax.addFlag(kChildRemovedFlag, kChildRemovedFlagLong);
    syntax.addFlag(kChildReorderedFlag, kChildReorderedFlagLong);
    syntax.addFlag(kHelpFlag, kHelpFlagLong);
    return syntax;
}

MStatus dagMessageCmd::addGenericCallback(MDagPath *dagPath, 
                                          MDagMessage::DagMessage msg, 
                                          MString cbName)
{
    MStatus status = MS::kFailure;

    if (NULL == dagPath) {
        MCallbackId id = MDagMessage::addDagCallback(   msg,
                                                        userDAGGenericCB, 
                                                        NULL, 
                                                        &status);
        if (MS::kSuccess == status) {
            MString info("Adding a callback for");
            info += cbName;
            info += "on all nodes";
            MGlobal::displayInfo(info);         
            callbackIds.append( id );
        } else {
            MString err("Could not add callback to");
            err += dagPath->fullPathName();
            MGlobal::displayError(err);
        }
    } else {
        MCallbackId id = MDagMessage::addDagCallback(*dagPath,
                                                    msg,
                                                    userDAGGenericCB, 
                                                    NULL, 
                                                    &status);
        if (MS::kSuccess == status) {
            MString info("Adding a callback for");
            info += cbName;
            info += "on ";
            info += dagPath->fullPathName();
            MGlobal::displayInfo(info);         
            callbackIds.append( id );
        } else {
            MString err("Could not add callback to");
            err += dagPath->fullPathName();
            MGlobal::displayError(err);
        }
    }

    return status;
}

MStatus dagMessageCmd::doIt( const MArgList& args)
//
// Takes the  nodes that are on the active selection list and adds an
// attriubte changed callback to each one.
//
{
    MStatus         status;
    MSelectionList  list;
    MArgDatabase argData(syntax(), args);

    status = argData.getObjects(list);
    if (MS::kSuccess != status) {
        MGlobal::displayError("Error getting objects");
        return status;
    }

    //  Get the flags
    //
    bool allDagUsed = argData.isFlagSet(kAllDagFlag);
    bool parentAddedUsed = argData.isFlagSet(kParentAddedFlag);
    bool parentRemovedUsed = argData.isFlagSet(kParentRemovedFlag);
    bool childAddedUsed = argData.isFlagSet(kChildAddedFlag);
    bool childRemovedUsed = argData.isFlagSet(kChildRemovedFlag);
    bool childReorderedUsed = argData.isFlagSet(kChildReorderedFlag);
    bool helpUsed = argData.isFlagSet(kHelpFlag);

    bool nothingSet = ( !allDagUsed && !parentAddedUsed && 
                        !parentRemovedUsed && !childAddedUsed && 
                        !childRemovedUsed && !childReorderedUsed && 
                        !helpUsed);

    if (nothingSet) {
        MGlobal::displayError("A flag must be used. dagMessage -help for availible flags.");
        return MS::kFailure;
    }

    if (argData.isFlagSet(kHelpFlag)) {
        MGlobal::displayInfo("dagMessage -help");
        MGlobal::displayInfo("\tdagMessage adds a callback to the selected nodes,");
        MGlobal::displayInfo("\tor if no nodes are selected, to all nodes. The callback");
        MGlobal::displayInfo("\tprints a message when called. When the plug-in is unloaded");
        MGlobal::displayInfo("\tthe callbacks are removed.");
        MGlobal::displayInfo("");
        MGlobal::displayInfo("\t-h -help : This message is printed");
        MGlobal::displayInfo("\t-ad -allDag : parent changes and child reorders");
        MGlobal::displayInfo("\t-pa -parentAdded : A parent is added");
        MGlobal::displayInfo("\t-pr -parentRemoved : A parent is removed");
        MGlobal::displayInfo("\t-ca -childAdded : A child is added (only for individual nodes)");
        MGlobal::displayInfo("\t-cr -childRemoved : A child is removed (only for individual nodes)");
        MGlobal::displayInfo("\t-cro -childReordered : A child is reordered");
        MGlobal::displayInfo("");
    }

    unsigned nObjs = list.length();
    if (nObjs == 0) {
        //  Add the callback for all changes of the specified type.
        //
        if (allDagUsed) {
            MCallbackId id = MDagMessage::addAllDagChangesCallback(userDAGGenericCB, NULL, &status);
            if (status) {
                callbackIds.append( id );
                MGlobal::displayInfo("Added a callback for all Dag changes on all nodes.\n");
            } else {
                MGlobal::displayError("Could not add a -allDag callback");
                return status;
            }
        }

        if (parentAddedUsed) {
            status = addGenericCallback(NULL, 
                                        MDagMessage::kParentAdded,
                                        MString(" parent added "));
            if (MS::kSuccess != status) {
                return status;
            }
        }

        if (parentRemovedUsed) {
            status = addGenericCallback(NULL, 
                                        MDagMessage::kParentRemoved,
                                        MString(" parent removed "));
            if (MS::kSuccess != status) {
                return status;
            }
        }       

        if (childAddedUsed) {
            MGlobal::displayError("-childAdded can only be used when a node is selected");
            status = MS::kFailure;
            return status;
        }

        if (childRemovedUsed) {
            MGlobal::displayError("-childRemoved can only be used when a node is selected");
            status = MS::kFailure;
            return status;
        }   

        if (childReorderedUsed) {
            status = addGenericCallback(NULL, 
                                        MDagMessage::kChildReordered,
                                        MString(" child reordered "));
            if (MS::kSuccess != status) {
                return status;
            }
        }   
    } else {
        for (unsigned int i=0; i< nObjs; i++) {
            MDagPath dagPath;
            list.getDagPath(i, dagPath);

            if (!dagPath.isValid()) {
                continue;
            }

            //  Add the callback for all changes of the specified type.
            //
            if (allDagUsed) {
                MCallbackId id = MDagMessage::addAllDagChangesCallback(dagPath, userDAGGenericCB, NULL, &status);
                if (status) {
                    callbackIds.append( id );
                    MString infoStr("Added a callback for all Dag changes on ");
                    infoStr += dagPath.fullPathName();
                    MGlobal::displayInfo(infoStr);
                } else {
                    MGlobal::displayError("Could not add a -allDag callback");
                    return status;
                }
            }

            if (parentAddedUsed) {
                status = addGenericCallback(&dagPath, 
                                            MDagMessage::kParentAdded,
                                            MString(" parent added "));
                if (MS::kSuccess != status) {
                    return status;
                }
            }

            if (parentRemovedUsed) {
                status = addGenericCallback(&dagPath, 
                                            MDagMessage::kParentRemoved,
                                            MString(" parent removed "));
                if (MS::kSuccess != status) {
                    return status;
                }
            }       

            if (childAddedUsed) {
                status = addGenericCallback(&dagPath, 
                                            MDagMessage::kChildAdded,
                                            MString(" child added "));
                if (MS::kSuccess != status) {
                    return status;
                }
            }

            if (childRemovedUsed) {
                status = addGenericCallback(&dagPath, 
                                            MDagMessage::kChildRemoved,
                                            MString(" child removed "));
                if (MS::kSuccess != status) {
                    return status;
                }
            }   

            if (childReorderedUsed) {
                status = addGenericCallback(&dagPath, 
                                            MDagMessage::kChildReordered,
                                            MString(" child reordered "));
                if (MS::kSuccess != status) {
                    return status;
                }
            }   
        }
    }
    
    return status;
}

//
// Plugin registration
//

MStatus initializePlugin( MObject obj )
{
    MFnPlugin plugin( obj );
    return plugin.registerCommand( kCmdName,
                                    dagMessageCmd::creator,
                                    dagMessageCmd::newSyntax);
}

MStatus uninitializePlugin( MObject obj)
{
    // Remove callbacks
    //
    for (unsigned int i=0; i<callbackIds.length(); i++ ) {
        MMessage::removeCallback( callbackIds[i] );
    }

    MFnPlugin plugin( obj );
    return plugin.deregisterCommand( kCmdName );
}