urho3d/Engine/Script/ScriptInstance.cpp

//
// Copyright (c) 2008-2013 the Urho3D project.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#include "Precompiled.h"
#include "Context.h"
#include "Log.h"
#include "MemoryBuffer.h"
#include "PhysicsEvents.h"
#include "PhysicsWorld.h"
#include "Profiler.h"
#include "ResourceCache.h"
#include "ResourceEvents.h"
#include "Scene.h"
#include "SceneEvents.h"
#include "Script.h"
#include "ScriptFile.h"
#include "ScriptInstance.h"

#include <angelscript.h>

#include "DebugNew.h"

namespace Urho3D
{

static const char* methodDeclarations[] = {
    "void Start()",
    "void Stop()",
    "void DelayedStart()",
    "void Update(float)",
    "void PostUpdate(float)",
    "void FixedUpdate(float)",
    "void FixedPostUpdate(float)",
    "void Load(Deserializer&)",
    "void Save(Serializer&)",
    "void ReadNetworkUpdate(Deserializer&)",
    "void WriteNetworkUpdate(Serializer&)",
    "void ApplyAttributes()"
};

ScriptInstance::ScriptInstance(Context* context) :
    Component(context),
    script_(GetSubsystem<Script>()),
    scriptObject_(0),
    fixedUpdateFps_(0),
    fixedUpdateInterval_(0.0f),
    fixedUpdateAcc_(0.0f),
    fixedPostUpdateAcc_(0.0f),
    subscribed_(false),
    subscribedPostFixed_(false)
{
    ClearScriptMethods();
    ClearScriptAttributes();
}

ScriptInstance::~ScriptInstance()
{
    ReleaseObject();
}

void ScriptInstance::RegisterObject(Context* context)
{
    context->RegisterFactory<ScriptInstance>(LOGIC_CATEGORY);
    
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_BOOL, "Is Enabled", IsEnabled, SetEnabled, bool, true, AM_DEFAULT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_RESOURCEREF, "Script File", GetScriptFileAttr, SetScriptFileAttr, ResourceRef, ResourceRef(ScriptFile::GetTypeStatic()), AM_DEFAULT);
    REF_ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_STRING, "Class Name", GetClassName, SetClassName, String, String::EMPTY, AM_DEFAULT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_INT, "Fixed Update FPS", GetFixedUpdateFps, SetFixedUpdateFps, int, 0, AM_DEFAULT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_FLOAT, "Time Accumulator", GetFixedUpdateAccAttr, SetFixedUpdateAccAttr, float, 0.0f, AM_FILE | AM_NOEDIT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_BUFFER, "Delayed Method Calls", GetDelayedMethodCallsAttr, SetDelayedMethodCallsAttr, PODVector<unsigned char>, Variant::emptyBuffer, AM_FILE | AM_NOEDIT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_BUFFER, "Script Data", GetScriptDataAttr, SetScriptDataAttr, PODVector<unsigned char>, Variant::emptyBuffer, AM_FILE | AM_NOEDIT);
    ACCESSOR_ATTRIBUTE(ScriptInstance, VAR_BUFFER, "Script Network Data", GetScriptNetworkDataAttr, SetScriptNetworkDataAttr, PODVector<unsigned char>, Variant::emptyBuffer, AM_NET | AM_NOEDIT);
}

void ScriptInstance::ApplyAttributes()
{
    if (scriptObject_ && methods_[METHOD_APPLYATTRIBUTES])
        scriptFile_->Execute(scriptObject_, methods_[METHOD_APPLYATTRIBUTES]);
}

void ScriptInstance::OnSetEnabled()
{
    UpdateEventSubscription();
}

bool ScriptInstance::CreateObject(ScriptFile* scriptFile, const String& className)
{
    className_ = String::EMPTY; // Do not create object during SetScriptFile()
    SetScriptFile(scriptFile);
    SetClassName(className);
    return scriptObject_ != 0;
}

void ScriptInstance::SetScriptFile(ScriptFile* scriptFile)
{
    if (scriptFile == scriptFile_ && scriptObject_)
        return;
    
    ReleaseObject();
    
    // Unsubscribe from the reload event of previous script file (if any), then subscribe to the new
    if (scriptFile_)
    {
        UnsubscribeFromEvent(scriptFile_, E_RELOADSTARTED);
        UnsubscribeFromEvent(scriptFile_, E_RELOADFINISHED);
    }
    if (scriptFile)
    {
        SubscribeToEvent(scriptFile, E_RELOADSTARTED, HANDLER(ScriptInstance, HandleScriptFileReload));
        SubscribeToEvent(scriptFile, E_RELOADFINISHED, HANDLER(ScriptInstance, HandleScriptFileReloadFinished));
    }
    
    scriptFile_ = scriptFile;
    
    CreateObject();
    MarkNetworkUpdate();
}

void ScriptInstance::SetClassName(const String& className)
{
    if (className == className_ && scriptObject_)
        return;
    
    ReleaseObject();
    
    className_ = className;
    CreateObject();
    MarkNetworkUpdate();
}

void ScriptInstance::SetFixedUpdateFps(int fps)
{
    fixedUpdateFps_ = Max(fps, 0);
    fixedUpdateInterval_ = fixedUpdateFps_ ? (1.0f / fixedUpdateFps_) : 0.0f;
    fixedUpdateAcc_ = 0.0f;
    fixedPostUpdateAcc_ = 0.0f;
    MarkNetworkUpdate();
}

bool ScriptInstance::Execute(const String& declaration, const VariantVector& parameters)
{
    if (!scriptObject_)
        return false;
    
    asIScriptFunction* method = scriptFile_->GetMethod(scriptObject_, declaration);
    return scriptFile_->Execute(scriptObject_, method, parameters);
}

bool ScriptInstance::Execute(asIScriptFunction* method, const VariantVector& parameters)
{
    if (!method || !scriptObject_)
        return false;
    
    return scriptFile_->Execute(scriptObject_, method, parameters);
}

void ScriptInstance::DelayedExecute(float delay, bool repeat, const String& declaration, const VariantVector& parameters)
{
    if (!scriptObject_)
        return;
    
    DelayedMethodCall call;
    call.period_ = call.delay_ = Max(delay, 0.0f);
    call.repeat_ = repeat;
    call.declaration_ = declaration;
    call.parameters_ = parameters;
    delayedMethodCalls_.Push(call);
    
    // Make sure we are registered to the scene update event, because delayed calls are executed there
    if (!subscribed_)
        UpdateEventSubscription();
}

void ScriptInstance::ClearDelayedExecute(const String& declaration)
{
    if (declaration.Empty())
        delayedMethodCalls_.Clear();
    else
    {
        for (Vector<DelayedMethodCall>::Iterator i = delayedMethodCalls_.Begin(); i != delayedMethodCalls_.End();)
        {
            if (declaration == i->declaration_)
                i = delayedMethodCalls_.Erase(i);
            else
                ++i;
        }
    }
}

void ScriptInstance::AddEventHandler(StringHash eventType, const String& handlerName)
{
    if (!scriptObject_)
        return;
    
    String declaration = "void " + handlerName + "(StringHash, VariantMap&)";
    asIScriptFunction* method = scriptFile_->GetMethod(scriptObject_, declaration);
    if (!method)
    {
        declaration = "void " + handlerName + "()";
        method = scriptFile_->GetMethod(scriptObject_, declaration);
        if (!method)
        {
            LOGERROR("Event handler method " + handlerName + " not found in " + scriptFile_->GetName());
            return;
        }
    }
    
    SubscribeToEvent(eventType, HANDLER_USERDATA(ScriptInstance, HandleScriptEvent, (void*)method));
}

void ScriptInstance::AddEventHandler(Object* sender, StringHash eventType, const String& handlerName)
{
    if (!scriptObject_)
        return;

    if (!sender)
    {
        LOGERROR("Null event sender for event " + String(eventType) + ", handler " + handlerName);
        return;
    }
    
    String declaration = "void " + handlerName + "(StringHash, VariantMap&)";
    asIScriptFunction* method = scriptFile_->GetMethod(scriptObject_, declaration);
    if (!method)
    {
        declaration = "void " + handlerName + "()";
        method = scriptFile_->GetMethod(scriptObject_, declaration);
        if (!method)
        {
            LOGERROR("Event handler method " + handlerName + " not found in " + scriptFile_->GetName());
            return;
        }
    }
    
    SubscribeToEvent(sender, eventType, HANDLER_USERDATA(ScriptInstance, HandleScriptEvent, (void*)method));
}

void ScriptInstance::SetScriptFileAttr(ResourceRef value)
{
    ResourceCache* cache = GetSubsystem<ResourceCache>();
    SetScriptFile(cache->GetResource<ScriptFile>(value.id_));
}

void ScriptInstance::SetDelayedMethodCallsAttr(PODVector<unsigned char> value)
{
    MemoryBuffer buf(value);
    delayedMethodCalls_.Resize(buf.ReadVLE());
    for (Vector<DelayedMethodCall>::Iterator i = delayedMethodCalls_.Begin(); i != delayedMethodCalls_.End(); ++i)
    {
        i->period_ = buf.ReadFloat();
        i->delay_ = buf.ReadFloat();
        i->repeat_ = buf.ReadBool();
        i->declaration_ = buf.ReadString();
        i->parameters_ = buf.ReadVariantVector();
    }
    
    if (delayedMethodCalls_.Size() && !subscribed_)
        UpdateEventSubscription();
}

void ScriptInstance::SetFixedUpdateAccAttr(float value)
{
    fixedUpdateAcc_ = value;
    fixedPostUpdateAcc_ = value;
}

void ScriptInstance::SetScriptDataAttr(PODVector<unsigned char> data)
{
    if (scriptObject_ && methods_[METHOD_LOAD])
    {
        MemoryBuffer buf(data);
        VariantVector parameters;
        parameters.Push(Variant((void*)static_cast<Deserializer*>(&buf)));
        scriptFile_->Execute(scriptObject_, methods_[METHOD_LOAD], parameters);
    }
}

void ScriptInstance::SetScriptNetworkDataAttr(PODVector<unsigned char> data)
{
    if (scriptObject_ && methods_[METHOD_READNETWORKUPDATE])
    {
        MemoryBuffer buf(data);
        VariantVector parameters;
        parameters.Push(Variant((void*)static_cast<Deserializer*>(&buf)));
        scriptFile_->Execute(scriptObject_, methods_[METHOD_READNETWORKUPDATE], parameters);
    }
}

ResourceRef ScriptInstance::GetScriptFileAttr() const
{
    return GetResourceRef(scriptFile_, ScriptFile::GetTypeStatic());
}

PODVector<unsigned char> ScriptInstance::GetDelayedMethodCallsAttr() const
{
    VectorBuffer buf;
    buf.WriteVLE(delayedMethodCalls_.Size());
    for (Vector<DelayedMethodCall>::ConstIterator i = delayedMethodCalls_.Begin(); i != delayedMethodCalls_.End(); ++i)
    {
        buf.WriteFloat(i->period_);
        buf.WriteFloat(i->delay_);
        buf.WriteBool(i->repeat_);
        buf.WriteString(i->declaration_);
        buf.WriteVariantVector(i->parameters_);
    }
    return buf.GetBuffer();
}

float ScriptInstance::GetFixedUpdateAccAttr() const
{
    return fixedUpdateAcc_;
}

PODVector<unsigned char> ScriptInstance::GetScriptDataAttr() const
{
    if (!scriptObject_ || !methods_[METHOD_SAVE])
        return PODVector<unsigned char>();
    else
    {
        VectorBuffer buf;
        VariantVector parameters;
        parameters.Push(Variant((void*)static_cast<Serializer*>(&buf)));
        scriptFile_->Execute(scriptObject_, methods_[METHOD_SAVE], parameters);
        return buf.GetBuffer();
    }
}

PODVector<unsigned char> ScriptInstance::GetScriptNetworkDataAttr() const
{
    if (!scriptObject_ || !methods_[METHOD_WRITENETWORKUPDATE])
        return PODVector<unsigned char>();
    else
    {
        VectorBuffer buf;
        VariantVector parameters;
        parameters.Push(Variant((void*)static_cast<Serializer*>(&buf)));
        scriptFile_->Execute(scriptObject_, methods_[METHOD_WRITENETWORKUPDATE], parameters);
        return buf.GetBuffer();
    }
}


void ScriptInstance::CreateObject()
{
    if (!scriptFile_ || className_.Empty())
        return;
    
    PROFILE(CreateScriptObject);
    
    scriptObject_ = scriptFile_->CreateObject(className_);
    if (scriptObject_)
    {
        // Map script object to script instance with userdata
        scriptObject_->SetUserData(this);
        
        ClearDelayedExecute();
        GetScriptMethods();
        GetScriptAttributes();
        UpdateEventSubscription();
        
        if (methods_[METHOD_START])
            scriptFile_->Execute(scriptObject_, methods_[METHOD_START]);
    }
    else
        LOGERROR("Failed to create object of class " + className_ + " from " + scriptFile_->GetName());
}

void ScriptInstance::ReleaseObject()
{
    if (scriptObject_)
    {
        if (methods_[METHOD_STOP])
            scriptFile_->Execute(scriptObject_, methods_[METHOD_STOP]);
        
        PODVector<StringHash> exceptions;
        exceptions.Push(E_RELOADSTARTED);
        exceptions.Push(E_RELOADFINISHED);
        UnsubscribeFromAllEventsExcept(exceptions, false);
        subscribed_ = false;
        subscribedPostFixed_ = false;
        
        ClearScriptMethods();
        ClearScriptAttributes();
        
        scriptObject_->SetUserData(0);
        scriptObject_->Release();
        scriptObject_ = 0;
    }
}

void ScriptInstance::ClearScriptMethods()
{
    for (unsigned i = 0; i < MAX_SCRIPT_METHODS; ++i)
        methods_[i] = 0;
    
    delayedMethodCalls_.Clear();
}

void ScriptInstance::ClearScriptAttributes()
{
    attributeInfos_ = *context_->GetAttributes(GetTypeStatic());
}

void ScriptInstance::GetScriptMethods()
{
    for (unsigned i = 0; i < MAX_SCRIPT_METHODS; ++i)
        methods_[i] = scriptFile_->GetMethod(scriptObject_, methodDeclarations[i]);
}

void ScriptInstance::GetScriptAttributes()
{
    attributeInfos_ = *context_->GetAttributes(GetTypeStatic());
    
    unsigned numProperties = scriptObject_->GetPropertyCount();
    for (unsigned i = 0; i < numProperties; ++i)
    {
        const char* name;
        int typeId;
        bool isPrivate;
        
        scriptObject_->GetObjectType()->GetProperty(i, &name, &typeId, &isPrivate);
        
        // Hide private variables or ones that begin with an underscore
        if (isPrivate || name[0] == '_')
            continue;
        
        AttributeInfo info;
        info.name_ = name;
        info.ptr_ = scriptObject_->GetAddressOfProperty(i);
        
        switch (typeId)
        {
        case asTYPEID_BOOL:
            info.type_ = VAR_BOOL;
            break;
            
        case asTYPEID_INT32:
        case asTYPEID_UINT32:
            info.type_ = VAR_INT;
            break;
            
        case asTYPEID_FLOAT:
            info.type_ = VAR_FLOAT;
            break;
            
        default:
            info.type_ = Variant::GetTypeFromName(GetSubsystem<Script>()->GetScriptEngine()->GetTypeDeclaration(typeId));
            break;
        }
        
        if (info.type_ != VAR_NONE)
            attributeInfos_.Push(info);
    }
}

void ScriptInstance::UpdateEventSubscription()
{
    Scene* scene = GetScene();
    if (!scene)
    {
        LOGERROR("Node is detached from scene, can not subscribe script object to update events");
        return;
    }
    
    bool enabled = scriptObject_ && IsEnabledEffective();
    
    if (enabled)
    {
        if (!subscribed_ && (methods_[METHOD_UPDATE] || methods_[METHOD_DELAYEDSTART] || delayedMethodCalls_.Size()))
        {
            SubscribeToEvent(scene, E_SCENEUPDATE, HANDLER(ScriptInstance, HandleSceneUpdate));
            subscribed_ = true;
        }
        
        if (!subscribedPostFixed_)
        {
            if (methods_[METHOD_POSTUPDATE])
                SubscribeToEvent(scene, E_SCENEPOSTUPDATE, HANDLER(ScriptInstance, HandleScenePostUpdate));
            
            PhysicsWorld* world = scene->GetComponent<PhysicsWorld>();
            if (world)
            {
                if (methods_[METHOD_FIXEDUPDATE])
                    SubscribeToEvent(world, E_PHYSICSPRESTEP, HANDLER(ScriptInstance, HandlePhysicsPreStep));
                if (methods_[METHOD_FIXEDPOSTUPDATE])
                    SubscribeToEvent(world, E_PHYSICSPOSTSTEP, HANDLER(ScriptInstance, HandlePhysicsPostStep));
            }
            else
            {
                if (methods_[METHOD_FIXEDUPDATE] || methods_[METHOD_FIXEDPOSTUPDATE])
                    LOGERROR("No physics world, can not subscribe script object to fixed update events");
            }
            
            
            subscribedPostFixed_ = true;
        }
    }
    else
    {
        if (subscribed_)
        {
            UnsubscribeFromEvent(scene, E_SCENEUPDATE);
            subscribed_ = false;
        }
        
        if (subscribedPostFixed_)
        {
            UnsubscribeFromEvent(scene, E_SCENEPOSTUPDATE);
            
            PhysicsWorld* world = scene->GetComponent<PhysicsWorld>();
            if (world)
            {
                UnsubscribeFromEvent(world, E_PHYSICSPRESTEP);
                UnsubscribeFromEvent(world, E_PHYSICSPOSTSTEP);
            }
            
            subscribedPostFixed_ = false;
        }
    }
}

void ScriptInstance::HandleSceneUpdate(StringHash eventType, VariantMap& eventData)
{
    if (!scriptObject_)
        return;
    
    using namespace SceneUpdate;
    
    float timeStep = eventData[P_TIMESTEP].GetFloat();
    
    // Execute delayed method calls
    for (unsigned i = 0; i < delayedMethodCalls_.Size();)
    {
        DelayedMethodCall& call = delayedMethodCalls_[i];
        bool remove = false;
        
        call.delay_ -= timeStep;
        if (call.delay_ <= 0.0f)
        {
            if (!call.repeat_)
                remove = true;
            else
                call.delay_ += call.period_;
            
            Execute(call.declaration_, call.parameters_);
        }
        
        if (remove)
            delayedMethodCalls_.Erase(i);
        else
            ++i;
    }
    
    // Execute delayed start before first update
    if (methods_[METHOD_DELAYEDSTART])
    {
        scriptFile_->Execute(scriptObject_, methods_[METHOD_DELAYEDSTART]);
        methods_[METHOD_DELAYEDSTART] = 0;  // Only execute once
    }
    
    if (methods_[METHOD_UPDATE])
    {
        VariantVector parameters;
        parameters.Push(timeStep);
        scriptFile_->Execute(scriptObject_, methods_[METHOD_UPDATE], parameters);
    }
}

void ScriptInstance::HandleScenePostUpdate(StringHash eventType, VariantMap& eventData)
{
    if (!scriptObject_)
        return;
    
    using namespace ScenePostUpdate;
    
    VariantVector parameters;
    parameters.Push(eventData[P_TIMESTEP]);
    scriptFile_->Execute(scriptObject_, methods_[METHOD_POSTUPDATE], parameters);
}

void ScriptInstance::HandlePhysicsPreStep(StringHash eventType, VariantMap& eventData)
{
    if (!scriptObject_)
        return;
    
    using namespace PhysicsPreStep;
    
    if (!fixedUpdateFps_)
    {
        VariantVector parameters;
        parameters.Push(eventData[P_TIMESTEP]);
        scriptFile_->Execute(scriptObject_, methods_[METHOD_FIXEDUPDATE], parameters);
    }
    else
    {
        float timeStep = eventData[P_TIMESTEP].GetFloat();
        fixedUpdateAcc_ += timeStep;
        if (fixedUpdateAcc_ >= fixedUpdateInterval_)
        {
            fixedUpdateAcc_ = fmodf(fixedUpdateAcc_, fixedUpdateInterval_);
            VariantVector parameters;
            parameters.Push(fixedUpdateInterval_);
            scriptFile_->Execute(scriptObject_, methods_[METHOD_FIXEDUPDATE], parameters);
        }
    }
}

void ScriptInstance::HandlePhysicsPostStep(StringHash eventType, VariantMap& eventData)
{
    if (!scriptObject_)
        return;
    
    using namespace PhysicsPostStep;
    
    if (!fixedUpdateFps_)
    {
        VariantVector parameters;
        parameters.Push(eventData[P_TIMESTEP]);
        scriptFile_->Execute(scriptObject_, methods_[METHOD_FIXEDPOSTUPDATE], parameters);
    }
    else
    {
        float timeStep = eventData[P_TIMESTEP].GetFloat();
        fixedPostUpdateAcc_ += timeStep;
        if (fixedPostUpdateAcc_ >= fixedUpdateInterval_)
        {
            fixedPostUpdateAcc_ = fmodf(fixedPostUpdateAcc_, fixedUpdateInterval_);
            VariantVector parameters;
            parameters.Push(fixedUpdateInterval_);
            scriptFile_->Execute(scriptObject_, methods_[METHOD_FIXEDPOSTUPDATE], parameters);
        }
    }
}

void ScriptInstance::HandleScriptEvent(StringHash eventType, VariantMap& eventData)
{
    if (!IsEnabledEffective() || !scriptFile_ || !scriptObject_)
        return;
    
    asIScriptFunction* method = static_cast<asIScriptFunction*>(GetEventHandler()->GetUserData());
    
    VariantVector parameters;
    if (method->GetParamCount() > 0)
    {
        parameters.Push(Variant((void*)&eventType));
        parameters.Push(Variant((void*)&eventData));
    }
    
    scriptFile_->Execute(scriptObject_, method, parameters);
}

void ScriptInstance::HandleScriptFileReload(StringHash eventType, VariantMap& eventData)
{
    ReleaseObject();
}

void ScriptInstance::HandleScriptFileReloadFinished(StringHash eventType, VariantMap& eventData)
{
    if (!className_.Empty())
        CreateObject();
}

Context* GetScriptContext()
{
    return static_cast<Script*>(asGetActiveContext()->GetEngine()->GetUserData())->GetContext();
}

ScriptInstance* GetScriptContextInstance()
{
    asIScriptContext* context = asGetActiveContext();
    asIScriptObject* object = context ? static_cast<asIScriptObject*>(context->GetThisPointer()) : 0;
    if (object)
        return static_cast<ScriptInstance*>(object->GetUserData());
    else
        return 0;
}

Node* GetScriptContextNode()
{
    ScriptInstance* instance = GetScriptContextInstance();
    return instance ? instance->GetNode() : 0;
}

Scene* GetScriptContextScene()
{
    Scene* scene = 0;
    Node* node = GetScriptContextNode();
    if (node)
        scene = node->GetScene();
    // If null, try to get the default scene
    if (!scene)
        scene = GetScriptContext()->GetSubsystem<Script>()->GetDefaultScene();
    
    return scene;
}

ScriptEventListener* GetScriptContextEventListener()
{
    // If context's this pointer is non-null, try to get the script instance. Else get the script file for procedural
    // event handling
    asIScriptContext* context = asGetActiveContext();
    if (context)
    {
        if (context->GetThisPointer())
            return GetScriptContextInstance();
        else
            return GetScriptContextFile();
    }
    else
        return 0;
}

Object* GetScriptContextEventListenerObject()
{
    return dynamic_cast<Object*>(GetScriptContextEventListener());
}


}