Question

我必须在我的项目的C ++应用程序中导入NPAPI DLL。我按照优秀的教程：http://colonelpanic.net/2009/03/building-a-firefox-plugin-part-one/

但是我在访问dll的方法时遇到了一些麻烦。（注意：在浏览器中，dll完全正常运行）。在调用主函数：NP_GetEntryPoints和NP_Initialize并检索ScriptableNPObject之后，方法的调用不返回任何值而没有错误。属性或方法名称与浏览器中的javascript（功能案例）中使用的名称相同。

有关信息，此示例中已替换属性和方法名称以及mime类型。

任何人都有想通过模拟浏览器的功能来调用dll的方法吗？

以下是主程序的一部分：

if (hDLL == 0)
{
    std::cout << "DLL failed to load!" << std::endl;
}
else
{
    std::cout << "DLL loaded!" << std::endl;

    //WRAP NP_GETENTRYPOINTS FUNCTION:
    _GetEntryPointsFunc = (GetEntryPointsFunc)GetProcAddress(hDLL, "NP_GetEntryPoints");
    if (_GetEntryPointsFunc)
    {
        std::cout << "Get NP_GetEntryPoints Function!" << std::endl;
        status = _GetEntryPointsFunc(pFuncs);

    }

    //WRAP NP_INITIALIZE FUNCTION:
    _InitializeFunc = (InitializeFunc)GetProcAddress(hDLL, "NP_Initialize");
    if (_InitializeFunc)
    {   
        std::cout << "Get NP_Initialize Function!" << std::endl;
        status = _InitializeFunc(&sBrowserFuncs);
    }


    int32_t       mode = NP_EMBED; 
    int32_t       argc = 7;
    static const char mimetype[] = "application/x-mime_type_of_my_plugin";

    char * argn[] = {"param1", "param2", "param3", "param4", "param5", "param6", "param7"};
    char * argv[] = { "value1", "value2", "value3", "value4", "value5", "value6", "value7" };



    NPObject np_object;
    uint16_t size;
    char* descritpionString;
    char* nameString;

  instance = &(plugin_instance.mNPP);
    status = pFuncs->newp((char*)mimetype, instance, (uint16_t)mode, argc, argn, argv, &saved);
    status = pFuncs->version; //OK  
    status = pFuncs->getvalue(instance,NPPVpluginDescriptionString,&descritpionString); //OK
    status = pFuncs->getvalue(instance,NPPVpluginNameString,&nameString); //OK

    status = pFuncs->getvalue(instance,NPPVpluginScriptableNPObject,&np_object); //ISSUE STARTS HERE

    std::cin.get();

}

这是在使用getvalue函数获取可编写脚本的NPObject之后调用的create_object函数：

NPObject* _createobject(NPP npp, NPClass* aClass)
{

if (!npp) {
    return nullptr;
}

if (!aClass) {
    return nullptr;
}

NPObject *npobj;

if (aClass->allocate) {
    npobj = aClass->allocate(npp, aClass);
} else {
    npobj = (NPObject *)malloc(sizeof(NPObject));
}

if (npobj) {
    npobj->_class = aClass;
    npobj->referenceCount = 1;

    //TEST:
            NPError status;
    NPString url;
    NPVariant result;
    NPVariant variant;
    NPIdentifier property = "existing_property";
    NPIdentifier *arrayId;
    uint32_t count = 2;

    const char *str = "https://test_url.com";
    url.UTF8Characters = str;//;
    url.UTF8Length = 20;

    variant.type = NPVariantType_String;
    variant.value.stringValue = url;
    NPVariant args[] = { variant };

    status = 1; //GENERIC ERROR VALUE
    status = npobj->_class->structVersion; //OK
    status = npobj->_class->hasMethod(npobj,L"existing_set_function"); //STATUS OK
    status = npobj->_class->enumerate(npobj, &arrayId, &count); //Privileged instruction ERROR
    status = npobj->_class->hasProperty(npobj, property); //STATUS OK
    status = npobj->_class->getProperty(npobj, property, &result); //STATUS OK BUT NO RESULT
    status = npobj->_class->invoke(npobj,L"existing_set_function",args,1,&result); //STATUS OK
    status = npobj->_class->invoke(npobj,L"existing_get_function",args,0,&result); //STATUS OK BUT NO RESULT
    status = npobj->_class->invokeDefault(npobj,args,0,&result); //STATUS OK BUT NO RESULT
    //END TEST
}
return npobj;
}

最后，这是一个声明ndata和pdata的plugin_instance方法：

nsNPAPIPluginInstance::nsNPAPIPluginInstance()
{
  mNPP.pdata = NULL;
  mNPP.ndata = this;
}

nsNPAPIPluginInstance::~nsNPAPIPluginInstance()
{

}

提前致谢。

Answer 1

虽然不清楚“没有结果”的含义，但是特权指令错误表明函数指针已关闭。

我从：

开始

检查structVersion >= NP_CLASS_STRUCT_VERSION_ENUM（否则为NPClass::enumerate is not available）
使用正确的npapi-sdk headers - 您的函数指针类型名称表明您没有这样做
使用简单的测试插件查看插件端发生的事情
请注意NPIdentifier在您的主机应用程序和插件之间匹配，即使用公共字符串 - ＆gt; NPIdentifier映射作为主机代码和NPN_GetStringIdentifier() - 如发布的这不能工作
请勿在创建功能中测试NPObject权限 - 插件可能会在NPN_CreateObject()返回

在C ++应用程序中导入NPAPI DLL

1 个答案: