Crash using block from mutable dictionary

Question

What can people tell me about why this program crashes:
#import <Foundation/Foundation.h>
@interface Action : NSObject
+ (void)execute;
@end
@implementation Action
+ (void)execute
    NSLog(@"The action was executed.");
@end
@interface ActionPerformer : NSObject {
@private
    NSMutableDictionary* _namedActions;
+ (ActionPerformer*) performer;
- (void)addAction:(NSString*)action withClass:(Class)class andSelector:(SEL)selector;
- (void)performAction:(NSString*)action;
@end
@implementation ActionPerformer
typedef void(^ActionBlock)();
+ (ActionPerformer*) performer
    ActionPerformer* performer = [[ActionPerformer alloc] init];
    performer->_namedActions = [NSMutableDictionary dictionary];
    return performer;
- (void)addAction:(NSString*)actionName withClass:(Class)class andSelector:(SEL)selector
    ActionBlock block = ^(){ [class performSelector:selector]; };
    // Verify things work
    block();
    [_namedActions setObject:block forKey:actionName];
- (void)performAction:(NSString*)actionName
    ActionBlock block = [_namedActions objectForKey:actionName];
    // Crash happens here!!!
    block();
@end
int main()
    @autoreleasepool {
        ActionPerformer* performer = [ActionPerformer performer];
        [performer addAction:@"action" withClass:[Action class]
            andSelector:@selector(execute)];
        [performer performAction:@"action"];       
    return 0;
I am using Mac OS X 10.6.8 with Xcode 4.2 and Apple LLVM compiler 3.0

Answer 1

Thanks etersoft,
I tried exactly what you suggested and I was able to call the block from the dictionary.
I assume that if someone is using garbage collection they don't need to worry about calling release on the block held in the dictionary.
Also, if someone is using automatic reference counting, I'm wondering if that would also take care of calling the release as well.