DECLARE_MSG_MAP参考实例

最新推荐文章于 2020-09-20 15:47:28 发布

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最新推荐文章于 2020-09-20 15:47:28 发布

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分类专栏： c++ 文章标签： DECLARE_MSG_MAP

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本文介绍了一个名为CModule的类，该类定义了消息映射机制，用于处理Windows消息和自定义请求。通过宏定义和结构体实现了消息与成员函数的绑定，提高了消息处理的灵活性和扩展性。

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#pragma once
#include <wtypes.h>
#include <afxmsg_.h>

class CModule;

typedef BOOL(CModule::*MODULE_PMSG)(LPCONTEXT_HEAD lpContext, LPREQUEST lpRequest);

struct MODULE_MSGMAP_ENTRY
{
    UINT nMessage;   // windows message
    MODULE_PMSG pfn;    // routine to call (or special value)
};

struct MODULE_MSGMAP
{
    const MODULE_MSGMAP* (PASCAL* pfnGetBaseMap)();
    const MODULE_MSGMAP_ENTRY* lpEntries;
};

#define DECLARE_MSG_MAP()                                         \
protected:                                                        \
    static const MODULE_MSGMAP* PASCAL GetThisMessageMap();       \
    virtual const MODULE_MSGMAP* GetMessageMap() const;

#define ON_MSG(message, memberFxn)                                              \
    { message,(MODULE_PMSG)(memberFxn) },

#define BEGIN_MSG_MAP(theClass, baseClass)                    \
    PTM_WARNING_DISABLE                                       \
    const MODULE_MSGMAP* theClass::GetMessageMap() const      \
        { return GetThisMessageMap(); }                       \
    const MODULE_MSGMAP* PASCAL theClass::GetThisMessageMap() \
    {                                                         \
        typedef theClass ThisClass;                           \
        typedef baseClass TheBaseClass;                       \
        static const MODULE_MSGMAP_ENTRY _messageEntries[] =  \
        {

#define END_MSG_MAP() \
            {0, (MODULE_PMSG)0 }                                   \
        };                                                         \
        static const MODULE_MSGMAP messageMap =                    \
        { &TheBaseClass::GetThisMessageMap, _messageEntries };     \
        return &messageMap;                                        \
    }                                                              \
    PTM_WARNING_RESTORE

class CModule
{
    DECLARE_MSG_MAP()
public:
    CModule();
    virtual ~CModule();
    BOOL OnRequest(LPCONTEXT_HEAD lpContext, LPREQUEST lpRequest);

};

#include "stdafx.h"
#include "Module.h"


CModule::CModule()
{
}


CModule::~CModule()
{
}

const MODULE_MSGMAP* CModule::GetMessageMap() const
{
    return GetThisMessageMap();
}

const MODULE_MSGMAP* CModule::GetThisMessageMap()
{
    static const MODULE_MSGMAP_ENTRY _messageEntries[] =
    {
        { 0, 0 }     // nothing here
    };
    static const MODULE_MSGMAP messageMap =
    {
        NULL,
        _messageEntries
    };
    return &messageMap;
}

#ifndef iHashMax
// iHashMax must be a power of two
#define iHashMax 512
#endif
struct MODULE_MSG_CACHE
{
    UINT nMsg;
    const MODULE_MSGMAP_ENTRY* lpEntry;
    const MODULE_MSGMAP* pMessageMap;
};
MODULE_MSG_CACHE _MsgCache[iHashMax] = { 0 };

const MODULE_MSGMAP_ENTRY* FindMessageEntry(const MODULE_MSGMAP_ENTRY* lpEntry, UINT nMsg)
{
    while (lpEntry->nMessage != 0)
    {
        if (lpEntry->nMessage == nMsg)
        {
            return lpEntry;
        }
        lpEntry++;
    }
    return NULL;
}

BOOL CModule::OnRequest(LPCONTEXT_HEAD lpContext, LPREQUEST lpRequest)
{
    UINT message = lpRequest->head.nRequest;

    const MODULE_MSGMAP* pMessageMap = GetMessageMap();
    UINT iHash = (LOWORD((DWORD_PTR)pMessageMap) ^ message) & (iHashMax - 1);
    MODULE_MSG_CACHE* pMsgCache = &_MsgCache[iHash];
    const MODULE_MSGMAP_ENTRY* lpEntry;
    if (message == pMsgCache->nMsg && pMessageMap == pMsgCache->pMessageMap)
    {
        lpEntry = pMsgCache->lpEntry;

    }
    else
    {
        pMsgCache->nMsg = message;
        pMsgCache->pMessageMap = pMessageMap;

        for (; pMessageMap->pfnGetBaseMap != NULL;
            pMessageMap = (*pMessageMap->pfnGetBaseMap)())
        {
            // Note: catches BEGIN_MSG_MAP(CMyClass, CMyClass)!
            ASSERT(pMessageMap != (*pMessageMap->pfnGetBaseMap)());
            if ((lpEntry = FindMessageEntry(pMessageMap->lpEntries, message)) != NULL)
            {
                pMsgCache->lpEntry = lpEntry;
                break;
            }

        }
    }
    if (lpEntry == NULL)
        return FALSE;

    return (this->*lpEntry->pfn)(lpContext, lpRequest);
}