/*

 * Copyright (C) 2010 Google Inc. All rights reserved.

 * Copyright (C) 2009 Pawel Hajdan (phajdan.jr@chromium.org)

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 *     * Redistributions of source code must retain the above copyright

 * notice, this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above

 * copyright notice, this list of conditions and the following disclaimer

 * in the documentation and/or other materials provided with the

 * distribution.

 *     * Neither the name of Google Inc. nor the names of its

 * contributors may be used to endorse or promote products derived from

 * this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

// This file contains definitions for CppBoundClass

// Here's the control flow of a JS method getting forwarded to a class.

// - Something calls our NPObject with a function like "Invoke".

// - CppNPObject's static invoke() function forwards it to its attached

//   CppBoundClass's invoke() method.

// - CppBoundClass has then overridden invoke() to look up the function

//   name in its internal map of methods, and then calls the appropriate

//   method.

#include "config.h"

#include "CppBoundClass.h"

#include "public/WebBindings.h"

#include "public/WebFrame.h"

#include "public/WebString.h"

#include <wtf/Assertions.h>

#include <wtf/OwnPtr.h>

using namespace WebKit;

using namespace std;

class CppVariantPropertyCallback : public CppBoundClass::PropertyCallback {

public:

    CppVariantPropertyCallback(CppVariant* value) : m_value(value) { }

    virtual bool getValue(CppVariant* value)

    {

        value->set(*m_value);

        return true;

    }

    virtual bool setValue(const CppVariant& value)

    {

        m_value->set(value);

        return true;

    }

private:

    CppVariant* m_value;

};

class GetterPropertyCallback : public CppBoundClass::PropertyCallback {

public:

    GetterPropertyCallback(CppBoundClass::GetterCallback* callback)

        : m_callback(callback) { }

    virtual bool getValue(CppVariant* value)

    {

        m_callback->run(value);

        return true;

    }

    virtual bool setValue(const CppVariant& value) { return false; }

private:

    OwnPtr<CppBoundClass::GetterCallback> m_callback;

};

// Our special NPObject type.  We extend an NPObject with a pointer to a

// CppBoundClass, which is just a C++ interface that we forward all NPObject

// callbacks to.

struct CppNPObject {

    NPObject parent; // This must be the first field in the struct.

    CppBoundClass* boundClass;

    //

    // All following objects and functions are static, and just used to interface

    // with NPObject/NPClass.

    //

    // An NPClass associates static functions of CppNPObject with the

    // function pointers used by the JS runtime.

    static NPClass npClass;

    // Allocate a new NPObject with the specified class.

    static NPObject* allocate(NPP, NPClass*);

    // Free an object.

    static void deallocate(NPObject*);

    // Returns true if the C++ class associated with this NPObject exposes the

    // given property.  Called by the JS runtime.

    static bool hasProperty(NPObject*, NPIdentifier);

    // Returns true if the C++ class associated with this NPObject exposes the

    // given method.  Called by the JS runtime.

    static bool hasMethod(NPObject*, NPIdentifier);

    // If the given method is exposed by the C++ class associated with this

    // NPObject, invokes it with the given arguments and returns a result.  Otherwise,

    // returns "undefined" (in the JavaScript sense).  Called by the JS runtime.

    static bool invoke(NPObject*, NPIdentifier,

                       const NPVariant* arguments, uint32_t argumentCount,

                       NPVariant* result);

    // If the given property is exposed by the C++ class associated with this

    // NPObject, returns its value.  Otherwise, returns "undefined" (in the

    // JavaScript sense).  Called by the JS runtime.

    static bool getProperty(NPObject*, NPIdentifier, NPVariant* result);

    // If the given property is exposed by the C++ class associated with this

    // NPObject, sets its value.  Otherwise, does nothing. Called by the JS

    // runtime.

    static bool setProperty(NPObject*, NPIdentifier, const NPVariant* value);

};

// Build CppNPObject's static function pointers into an NPClass, for use

// in constructing NPObjects for the C++ classes.

NPClass CppNPObject::npClass = {

    NP_CLASS_STRUCT_VERSION,

    CppNPObject::allocate,

    CppNPObject::deallocate,

    /* NPInvalidateFunctionPtr */ 0,

    CppNPObject::hasMethod,

    CppNPObject::invoke,

    /* NPInvokeDefaultFunctionPtr */ 0,

    CppNPObject::hasProperty,

    CppNPObject::getProperty,

    CppNPObject::setProperty,

    /* NPRemovePropertyFunctionPtr */ 0

};

NPObject* CppNPObject::allocate(NPP npp, NPClass* aClass)

{

    CppNPObject* obj = new CppNPObject;

    // obj->parent will be initialized by the NPObject code calling this.

    obj->boundClass = 0;

    return &obj->parent;

}

void CppNPObject::deallocate(NPObject* npObj)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    delete obj;

}

bool CppNPObject::hasMethod(NPObject* npObj, NPIdentifier ident)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    return obj->boundClass->hasMethod(ident);

}

bool CppNPObject::hasProperty(NPObject* npObj, NPIdentifier ident)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    return obj->boundClass->hasProperty(ident);

}

bool CppNPObject::invoke(NPObject* npObj, NPIdentifier ident,

                         const NPVariant* arguments, uint32_t argumentCount,

                         NPVariant* result)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    return obj->boundClass->invoke(ident, arguments, argumentCount, result);

}

bool CppNPObject::getProperty(NPObject* npObj, NPIdentifier ident, NPVariant* result)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    return obj->boundClass->getProperty(ident, result);

}

bool CppNPObject::setProperty(NPObject* npObj, NPIdentifier ident, const NPVariant* value)

{

    CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

    return obj->boundClass->setProperty(ident, value);

}

CppBoundClass::~CppBoundClass()

{

    for (MethodList::iterator i = m_methods.begin(); i != m_methods.end(); ++i)

        delete i->second;

    for (PropertyList::iterator i = m_properties.begin(); i != m_properties.end(); ++i)

        delete i->second;

    // Unregister ourselves if we were bound to a frame.

    if (m_boundToFrame)

        WebBindings::unregisterObject(NPVARIANT_TO_OBJECT(m_selfVariant));

}

bool CppBoundClass::hasMethod(NPIdentifier ident) const

{

    return m_methods.find(ident) != m_methods.end();

}

bool CppBoundClass::hasProperty(NPIdentifier ident) const

{

    return m_properties.find(ident) != m_properties.end();

}

bool CppBoundClass::invoke(NPIdentifier ident,

                           const NPVariant* arguments,

                           size_t argumentCount,

                           NPVariant* result) {

    MethodList::const_iterator end = m_methods.end();

    MethodList::const_iterator method = m_methods.find(ident);

    Callback* callback;

    if (method == end) {

        if (!m_fallbackCallback.get()) {

            VOID_TO_NPVARIANT(*result);

            return false;

        }

        callback = m_fallbackCallback.get();

    } else

        callback = (*method).second;

    // Build a CppArgumentList argument vector from the NPVariants coming in.

    CppArgumentList cppArguments(argumentCount);

    for (size_t i = 0; i < argumentCount; i++)

        cppArguments[i].set(arguments[i]);

    CppVariant cppResult;

    callback->run(cppArguments, &cppResult);

    cppResult.copyToNPVariant(result);

    return true;

}

bool CppBoundClass::getProperty(NPIdentifier ident, NPVariant* result) const

{

    PropertyList::const_iterator callback = m_properties.find(ident);

    if (callback == m_properties.end()) {

        VOID_TO_NPVARIANT(*result);

        return false;

    }

    CppVariant cppValue;

    if (!callback->second->getValue(&cppValue))

        return false;

    cppValue.copyToNPVariant(result);

    return true;

}

bool CppBoundClass::setProperty(NPIdentifier ident, const NPVariant* value)

{

    PropertyList::iterator callback = m_properties.find(ident);

    if (callback == m_properties.end())

        return false;

    CppVariant cppValue;

    cppValue.set(*value);

    return (*callback).second->setValue(cppValue);

}

void CppBoundClass::bindCallback(const string& name, Callback* callback)

{

    NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());

    MethodList::iterator oldCallback = m_methods.find(ident);

    if (oldCallback != m_methods.end()) {

        delete oldCallback->second;

        if (!callback) {

            m_methods.remove(oldCallback);

            return;

        }

    }

    m_methods.set(ident, callback);

}

void CppBoundClass::bindGetterCallback(const string& name, GetterCallback* callback)

{

    PropertyCallback* propertyCallback = callback ? new GetterPropertyCallback(callback) : 0;

    bindProperty(name, propertyCallback);

}

void CppBoundClass::bindProperty(const string& name, CppVariant* prop)

{

    PropertyCallback* propertyCallback = prop ? new CppVariantPropertyCallback(prop) : 0;

    bindProperty(name, propertyCallback);

}

void CppBoundClass::bindProperty(const string& name, PropertyCallback* callback)

{

    NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());

    PropertyList::iterator oldCallback = m_properties.find(ident);

    if (oldCallback != m_properties.end()) {

        delete oldCallback->second;

        if (!callback) {

            m_properties.remove(oldCallback);

            return;

        }

    }

    m_properties.set(ident, callback);

}

bool CppBoundClass::isMethodRegistered(const string& name) const

{

    NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());

    MethodList::const_iterator callback = m_methods.find(ident);

    return callback != m_methods.end();

}

CppVariant* CppBoundClass::getAsCppVariant()

{

    if (!m_selfVariant.isObject()) {

        // Create an NPObject using our static NPClass.  The first argument (a

        // plugin's instance handle) is passed through to the allocate function

        // directly, and we don't use it, so it's ok to be 0.

        NPObject* npObj = WebBindings::createObject(0, &CppNPObject::npClass);

        CppNPObject* obj = reinterpret_cast<CppNPObject*>(npObj);

        obj->boundClass = this;

        m_selfVariant.set(npObj);

        WebBindings::releaseObject(npObj); // CppVariant takes the reference.

    }

    ASSERT(m_selfVariant.isObject());

    return &m_selfVariant;

}

void CppBoundClass::bindToJavascript(WebFrame* frame, const WebString& classname)

{

    // BindToWindowObject will take its own reference to the NPObject, and clean

    // up after itself.  It will also (indirectly) register the object with V8,

    // so we must remember this so we can unregister it when we're destroyed.

    frame->bindToWindowObject(classname, NPVARIANT_TO_OBJECT(*getAsCppVariant()));

    m_boundToFrame = true;

}