PLPatchMaster

PLPatchMaster provides an easy-to-use block-based swizzling API, using the block trampoline library provided by PLBlockIMP, and a set of custom assembly trampolines for ARMv7, ARMv7s, ARM64, and x86-64.

PLPatchMaster can apply patches to currently loaded classes, as well as classes that have not yet been loaded (eg, will be loaded at a future time) by registering a listener for dyld image events.

Use it at your own risk; swizzling in production software is rarely, if ever, a particularly good idea.

PLPatchMaster is released under the MIT license.

Basic Use

Use a block to swizzle -[UIWindow sendEvent:]:

[UIWindow pl_patchInstanceSelector: @selector(sendEvent:) withReplacementBlock: ^(PLPatchIMP *patch, UIEvent *event) {
    NSObject *obj = PLPatchGetSelf(patch);
    
    // Ignore 'remote control' events
    if (event.type == UIEventTypeRemoteControl)
        return;

    // Forward everything else
    return PLPatchIMPFoward(patch, void (*)(id, SEL, UIEvent *), event);
}];

Advanced Use

Register a future patch on a class that has not been loaded yet (eg, it's loaded dynamically at runtime):

[[PLPatchMaster master] patchFutureClassWithName: @"ExFATCameraDeviceManager" withReplacementBlock: ^(PLPatchIMP *patch, id *arg) {
    /* Forward the message to the next IMP */
    PLPatchIMPFoward(patch, void (*)(id, SEL, id *));
    
    /* Log the event */
    NSLog(@"FAT camera device ejected");
}];

PLPatchMaster registers a listener for dyld image events, and will automatically swizzle the target class when its Mach-O image is loaded.