subclass.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 100 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
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* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
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****************************************************************************/


#include "winvi.h"
#include "subclass.h"
#include "keys.h"

proc_entry  *procHead;
proc_entry  *procTail;

void SubclassGenericAdd( HWND hwnd, WNDPROC proc )
{
    proc_entry *newProc;

    newProc = MemAlloc( sizeof( proc_entry ) );

    newProc->hwnd = hwnd;
    newProc->oldProc = (WNDPROC) GetWindowLong( hwnd, GWL_WNDPROC );
    newProc->newProc = (WNDPROC) MakeProcInstance( (FARPROC) proc,
                                 InstanceHandle );
    SetWindowLong( hwnd, GWL_WNDPROC, (LONG) newProc->newProc );

    AddLLItemAtEnd( (ss**)&procHead, (ss**)&procTail, (ss*)newProc );
}

void SubclassGenericRemove( HWND hwnd )
{
    proc_entry  *findProc;

    findProc = procHead;
    while( findProc && findProc->hwnd != hwnd ) {
        findProc = findProc->next;
    }
    assert( findProc != NULL );

    SetWindowLong( hwnd, GWL_WNDPROC, (LONG) findProc->oldProc );
    #ifndef __NT__
    FreeProcInstance( (FARPROC)findProc->newProc );
    #endif

    DeleteLLItem( (ss**)&procHead, (ss**)&procTail, (ss*)findProc );
    MemFree( findProc );
}

void SubclassGenericInit( void )
{
    procHead = NULL;
    procTail = NULL;
}

void SubclassGenericFini( void )
{
    assert( procHead == NULL );
}

WNDPROC SubclassGenericFindOldProc( HWND hwnd )
{
    // doing a search on every message is a huge time hit, but this is
    // by no means time-critical.  Perhaps automatically registering a
    // new class based on the hwnd parameter with an extra few bytes
    // for the old window... /*BW*/
    proc_entry  *findProc;

    findProc = procHead;
    while( findProc && findProc->hwnd != hwnd ) {
        findProc = findProc->next;
    }
    assert( findProc != NULL );
    return( findProc->oldProc );
}