CGMouseDeltaFix.m

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/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
#import "CGMouseDeltaFix.h"
#import "CGPrivateAPI.h"

#import <Foundation/Foundation.h>
#import <mach-o/dyld.h>


// We will try to automatically fall back to using the original CGGetLastMouseDelta when we are on a system new enough to have the fix.  Any version of CoreGraphics past 1.93.0 will have the fixed version.


static BOOL originalVersionShouldWork = YES;
static CGMouseDelta CGFix_Mouse_DeltaX, CGFix_Mouse_DeltaY;

static void CGFix_NotificationCallback(CGSNotificationType note, CGSNotificationData data, CGSByteCount dataLength, CGSNotificationArg arg);

static CGSRegisterNotifyProcType registerNotifyProc = NULL;

void CGFix_Initialize()
{
    NSAutoreleasePool *pool;
    NSBundle *cgBundle;
    NSString *version;
    NSArray *components;
    
    if (registerNotifyProc)
        // We've already been called once and have registered our callbacks.  If the original version works, this will be NULL, but we'll end up doing nothing (again, possibly).
        return;

    //NSLog(@"CGFix_Initialize\n");
        
    pool = [[NSAutoreleasePool alloc] init];
    cgBundle = [NSBundle bundleWithPath: @"/System/Library/Frameworks/ApplicationServices.framework/Frameworks/CoreGraphics.framework"];
    if (!cgBundle) {
        // If it's moved, it must be newer than what we know about and should work
        //NSLog(@"No /System/Library/Frameworks/ApplicationServices.framework/Frameworks/CoreGraphics.framework\n");
        goto done;
    }
    
    version = [[cgBundle infoDictionary] objectForKey: @"CFBundleShortVersionString"];
    components = [version componentsSeparatedByString: @"."];
    //NSLog(@"version = %@\n", version);
    //NSLog(@"components = %@\n", components);


    if ([components count] < 2)
        // We don't understand this versioning scheme.  Must have changed.
        goto done;
    
    if (![[components objectAtIndex: 0] isEqualToString: @"1"] || [[components objectAtIndex: 1] intValue] > 93)
        // This version should be new enough to work
        goto done;
    
    // Look up the function pointer we need to register our callback.
    if (!NSIsSymbolNameDefined("_CGSRegisterNotifyProc")) {
        //NSLog(@"No _CGSRegisterNotifyProc\n");
        goto done;
    }
    
    registerNotifyProc = NSAddressOfSymbol(NSLookupAndBindSymbol("_CGSRegisterNotifyProc"));
    //NSLog(@"registerNotifyProc = 0x%08x", registerNotifyProc);

    // Must not work if we got here
    originalVersionShouldWork = NO;
    
    // We want to catch all the events that could possible indicate mouse movement and sum them up
    registerNotifyProc( CGFix_NotificationCallback, kCGSEventNotificationMouseMoved, NULL);
    registerNotifyProc( CGFix_NotificationCallback, kCGSEventNotificationLeftMouseDragged, NULL);
    registerNotifyProc( CGFix_NotificationCallback, kCGSEventNotificationRightMouseDragged, NULL);
    registerNotifyProc( CGFix_NotificationCallback, kCGSEventNotificationNotificationOtherMouseDragged, NULL);
    
done:
    [pool release];
}

void CGFix_GetLastMouseDelta(CGMouseDelta *dx, CGMouseDelta *dy)
{
    if (originalVersionShouldWork) {
        CGGetLastMouseDelta(dx, dy);
        return;
    }
    
    *dx = CGFix_Mouse_DeltaX;
    *dy = CGFix_Mouse_DeltaY;
    
    CGFix_Mouse_DeltaX = CGFix_Mouse_DeltaY = 0;
}

static void CGFix_NotificationCallback(CGSNotificationType note, CGSNotificationData data, CGSByteCount dataLength, CGSNotificationArg arg)
{
    CGSEventRecordPtr event;

    //fprintf(stderr, "CGFix_NotificationCallback(note=%d, date=0x%08x, dataLength=%d, arg=0x%08x)\n", note, data, dataLength, arg);
    
#ifdef DEBUG
    if ((note != kCGSEventNotificationMouseMoved && 
         note != kCGSEventNotificationLeftMouseDragged &&
         note != kCGSEventNotificationRightMouseDragged &&
         note != kCGSEventNotificationNotificationOtherMouseDragged) ||
         dataLength != sizeof (CGSEventRecord))
         fprintf(stderr, "Unexpected arguments to callback function CGFix_NotificationCallback(note=%d, date=0x%08x, dataLength=%d, arg=0x%08x)\n", note, data, dataLength, arg);
         abort();
    }
#endif

    event = (CGSEventRecordPtr)data;

    CGFix_Mouse_DeltaX += event->data.move.deltaX;
    CGFix_Mouse_DeltaY += event->data.move.deltaY;
    //fprintf(stderr, "  dx += %d, dy += %d\n", event->data.move.deltaX, event->data.move.deltaY);
}

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