Nebula2探秘05-RTTI-优快云博客

本文链接：https://blog.youkuaiyun.com/zhaowei001/article/details/2268739

本文介绍 Nebula2 中 RTTI 的实现方式，主要依赖于 nClass 和 nObject 类。通过示例展示了如何使用 IsA() 和 IsInstanceOf() 方法来检查类的继承关系及对象实例所属。

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Nebula2探秘05-RTTI

happykevins文

Nebula2的RTTI支持都是在nObject这一层实现的，每个继承自nObject的类都有IsA()和IsInstanceof()两个方法，前者用于判断继承关系，后者则用于判断一个对象是否为指定类的实例，下面的代码说明了他们的用法。

/****************************************************************************/
/*    Nebula2 - Tutorial 05                                                    */
/*  Nebula2 RTTI                                                            */
/*  author: happykevins                                                        */
/****************************************************************************/

///----------------------------------------------------------------------------
/// +必要头文件
#include "kernel/nkernelserver.h"
#include "kernel/ntimeserver.h"
#include "kernel/nfileserver2.h"
/// -必要头文件
///----------------------------------------------------------------------------

///----------------------------------------------------------------------------
/// +链接库
#pragma comment(lib, "wsock32.lib")
#pragma comment(lib, "d_nkernel.lib")
/// -链接库
///----------------------------------------------------------------------------

///----------------------------------------------------------------------------
/// +Application
int main(int argc, const char** argv)
{
    /// 创建KernelServer
    nKernelServer* ks = n_new(nKernelServer);

    ///----------------------------------------------------------------------------
    /// +Nebula2 RTTI Test
    /// @note:
    ///        Nebula2 RTTI implement mostly depends on nClass && nObject

    /// firstly: we got some instance (all inherited from nObject)
    nRoot* nroot = (nRoot*)ks->New("nroot");
    nObject* nobject = (nObject*)ks->New("nobject");
    nTimeServer* ntimeserver = (nTimeServer*)ks->Lookup("/sys/servers/time");
    nFileServer2* nfileserver2 = (nFileServer2*)ks->Lookup("/sys/servers/file2");

    /// secondly: Test RTTI Info.
    /// use 'IsA' & 'IsInstanceOf' methods

    // 1. nroot is a nroot?
    n_printf("[%s] is %s [%s] ",
        nroot->GetClass()->GetName(),
        nroot->IsA("nroot") ? "/b" : "not",
        "nroot");
    // 2. nroot is a nobject?
    n_printf("[%s] is %s [%s] ",
        nroot->GetClass()->GetName(),
        nroot->IsA(ks->FindClass("nobject")) ? "/b" : "not",
        "nobject");
    // 3. nobject is a nroot?
    n_printf("[%s] is %s [%s] ",
        nobject->GetClass()->GetName(),
        nobject->IsA("nroot") ? "/b" : "not",
        "nroot");
    // 4. ntimerserver is a nroot?
    n_printf("[%s] is %s [%s] ",
        ntimeserver->GetClass()->GetName(),
        ntimeserver->IsA("nroot") ? "/b" : "not",
        "nroot");
    // 5. nroot is instance of nroot?
    n_printf("[%s] is %s instance of [%s] ",
        nroot->GetClass()->GetName(),
        nroot->IsInstanceOf(ks->FindClass("nroot")) ? "/b" : "not",
        "nroot");
    // 6. nroot is instance of nobject?
    n_printf("[%s] is %s instance of [%s] ",
        nroot->GetClass()->GetName(),
        nroot->IsInstanceOf(ks->FindClass("nobject")) ? "/b" : "not",
        "nobject");
    // 7. nfileserver2 is a nobject?
    n_printf("[%s] is %s [%s] ",
        nfileserver2->GetClass()->GetName(),
        nfileserver2->IsA("nobject") ? "/b" : "not",
        "nobject");
    // 8. nfileserver2 is a ntimeserver?
    n_printf("[%s] is %s [%s] ",
        nfileserver2->GetClass()->GetName(),
        nfileserver2->IsA("ntimeserver") ? "/b" : "not",
        "ntimeserver");

    /// +Nebula2 RTTI Test
    ///----------------------------------------------------------------------------


    /// 销毁KernelServer
    n_delete(ks);

    getchar();
    return 0;
}
/// -Application
///----------------------------------------------------------------------------