VKBlockSelector.h.m

//
//  VKBlockSelector.h
//

#include <objc/runtime.h>
#import <Foundation/Foundation.h>

/*
 * note: each file has its own!
 */
static const char *BLOCK_SELECTOR_ASSOCIATION = "blockselector";

static void
selector_IMP(id self, SEL _cmd, id arg)
{
    NSDictionary *selinfo = objc_getAssociatedObject(self, BLOCK_SELECTOR_ASSOCIATION);
    assert(selinfo != nil);
    
    NSString *name = NSStringFromSelector(_cmd);
    void (^block)(id arg) = [selinfo objectForKey:name];

    block(arg);
}

static SEL
block_selector(id self, SEL sel, void (^block)(id arg))
{    
    id block_copy = Block_copy(block);

    NSMutableDictionary *selinfo = objc_getAssociatedObject(self, BLOCK_SELECTOR_ASSOCIATION);
    if (selinfo == nil) {
        selinfo = [[[NSMutableDictionary alloc] init] autorelease];
        objc_setAssociatedObject(self, BLOCK_SELECTOR_ASSOCIATION, selinfo, OBJC_ASSOCIATION_RETAIN);
    }

    [selinfo setObject:block_copy forKey:NSStringFromSelector(sel)];
    [block_copy release];

    BOOL ok = class_addMethod([self class], sel, (IMP)selector_IMP, "v@:@");
    assert(ok && "method already exists");

    return sel;
}

#if 0
  // Usage:
  UISwipeGestureRecognizer *r1 = [[UISwipeGestureRecognizer alloc] 
                                    initWithTarget:self action:block_selector(self, @selector(handleSwipeUp:),
                                                                    ^(id arg) {
                                                                        [self.playerController volumeUp];
                                                                        [self release]; // was retained
                                                                    })];
#endif