I have a script that loops a lot. Sometimes I will need to stop it manually. It works fine in the applescript editor because I can just hit stop, but if this is going to be a standalone app made in xcode then how would I create a stop button? I have heard something about threading, but I dont understand it yet.
lets say that my code is:
on buttonClicked_(sender)
repeat
say "help"
end repeat
end buttonClicked_
Button clicked would be a ui button that says "run"
I don't know ApplescriptObjC, but here's how to do it in objective-c. I'm sure you can figure out how to convert it.
The idea with threading is that your program runs on a main thread. When you enter the repeat loop that will take up all of your applications resources and thus block the main thread so you can't do anything else until you exit the repeat loop. Therefore run your repeat loop on a background thread, thus the main thread is free to handle other tasks, such as pressing a button.
For example, suppose you have a button on your interface and a BOOL variable setup in your code. On every button press the BOOL becomes YES/NO. Here's a button method. Notice we use "detachNewThreadSelector" to run your repeat loop on a background thread.
-(IBAction)buttonPress:(id)sender {
if (theBool == YES) {
theBool = NO;
[sender setTitle:#"Start"];
} else {
theBool = YES;
[sender setTitle:#"Stop"];
}
[NSThread detachNewThreadSelector:#selector(theMethod) toTarget:self withObject:nil];
}
And here's what your "background thread" method could look like. Since I don't know if you're using ARC or not, it contains an autorelease pool which handles releasing memory. The main thread has one automatically but since this is on a background thread we must create our own.
-(void)theMethod {
if (theBool == YES) {
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
repeat
if (theBool == NO) {
exit repeat
}
say "help"
end repeat
[pool drain];
}
}
Good luck.
Related
I'm writing a "UIElement" app that shows a status window on the side of the screen, similar to the Dock.
Now, when a program takes over the entire screen, I need to hide my status window, just like the Dock does.
What are my options to detect this and the inverse event?
I like to avoid polling via a timed event and also cannot use undocumented tricks (such as suggested here)
What doesn't work:
Registering a Carbon Event Handler for the kEventAppSystemUIModeChanged event isn't sufficient - it works to detect VLC's full screen mode, but not for modern Cocoa apps that use the new fullscreen widget at the top right corner of their windows.
Similarly, following Apple's instructions about the NSApplication presentationOptions API by observing changes to the currentSystemPresentationOptions property does not help, either - again, it only informs about VLC's fullscreen mode, but not about apps using the window' top right fullscreen widget.
Monitoring changes to the screen configuration using CGDisplayRegisterReconfigurationCallback is not working because there aren't any callbacks for these fullscreen modes.
Based on #Chuck's suggestion, I've come up with a solution that works somewhat, but may not be foolproof.
The solution is based on the assumption that 10.7's new fullscreen mode for windows moves these windows to a new Screen Space. Therefore, we subscribe to notifications for changes to the active space. In that notification handler, we check the window list to detect whether the menubar is included. If it is not, it probably means that we're in a fullscreen space.
Checking for the presence of the "Menubar" window is the best test I could come up with based on Chuck's idea. I don't like it too much, though, because it makes assumptions on the naming and presence of internally managed windows.
Here's the test code that goes inside AppDelegate.m, which also includes the test for the other app-wide fullscreen mode:
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification
{
NSApplication *app = [NSApplication sharedApplication];
// Observe full screen mode from apps setting SystemUIMode
// or invoking 'setPresentationOptions'
[app addObserver:self
forKeyPath:#"currentSystemPresentationOptions"
options:NSKeyValueObservingOptionNew
context:NULL];
// Observe full screen mode from apps using a separate space
// (i.e. those providing the fullscreen widget at the right
// of their window title bar).
[[[NSWorkspace sharedWorkspace] notificationCenter]
addObserverForName:NSWorkspaceActiveSpaceDidChangeNotification
object:NULL queue:NULL
usingBlock:^(NSNotification *note)
{
// The active space changed.
// Now we need to detect if this is a fullscreen space.
// Let's look at the windows...
NSArray *windows = CFBridgingRelease(CGWindowListCopyWindowInfo
(kCGWindowListOptionOnScreenOnly, kCGNullWindowID));
//NSLog(#"active space change: %#", windows);
// We detect full screen spaces by checking if there's a menubar
// in the window list.
// If not, we assume it's in fullscreen mode.
BOOL hasMenubar = NO;
for (NSDictionary *d in windows) {
if ([d[#"kCGWindowOwnerName"] isEqualToString:#"Window Server"]
&& [d[#"kCGWindowName"] isEqualToString:#"Menubar"]) {
hasMenubar = YES;
break;
}
}
NSLog(#"fullscreen: %#", hasMenubar ? #"No" : #"Yes");
}
];
}
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context
{
if ([keyPath isEqual:#"currentSystemPresentationOptions"]) {
NSLog(#"currentSystemPresentationOptions: %#", [change objectForKey:NSKeyValueChangeNewKey]); // a value of 4 indicates fullscreen mode
}
}
Since my earlier answer doesn't work for detecting full screen mode between apps, I did some experimentation. Starting with the solution that Thomas Tempelmann came up with of checking the presence of menu bar, I found a variation that I think could be more reliable.
The problem with checking for the menu bar is that in full screen mode you can move the mouse cursor to the top of the screen to make the menu bar appear, but you're still in full screen mode. I did some crawling through the CGWindow info, and discovered that when I enter full screen, there is window named "Fullscreen Backdrop" owned by the "Dock", and it's not there when not in full screen mode.
This is on Catalina (10.15.6) in an Xcode playground, so it should be tested in a real app, and on Big Sur (or whatever the current OS is, when you're reading this).
Here's the code (in Swift... easier to quickly test something)
func isFullScreen() -> Bool
{
guard let windows = CGWindowListCopyWindowInfo(.optionOnScreenOnly, kCGNullWindowID) else {
return false
}
for window in windows as NSArray
{
guard let winInfo = window as? NSDictionary else { continue }
if winInfo["kCGWindowOwnerName"] as? String == "Dock",
winInfo["kCGWindowName"] as? String == "Fullscreen Backdrop"
{
return true
}
}
return false
}
EDIT NOTE: This answer unfortunately doesn't provide a solution for detecting full screen in a different app, which is what the OP was asking. I'm leaving it because it does answer the question for detecting in in the same app going full screen - for example in a generic library that needs to know to automatically update keyEquivalents and title for an explicitly added "Enter Full Screen" menu item rather than Apple's automatically added menu item.
Although this question is quite old now, I've had to detect full screen mode in Swift recently. While it's not as simple as querying some flag in NSWindow, as we would hope for, there is an easy and reliable solution that has been available since macOS 10.7.
Whenever a window is about to enter full screen mode NSWindow sends a willEnterFullScreenNotification notification, and when it is about to exit full screen mode, it sends willExitFullScreenNotification. So you add an observer for those notifications. In the following code, I use them to set a global boolean flag.
import Cocoa
/*
Since notification closures can be run concurrently, we need to guard against
races on the Boolean flag. We could use DispatchSemaphore, but it's kind
over-kill for guarding a simple read/write to a boolean variable.
os_unfair_lock is appropriate for nanosecond-level contention. If the wait
could be milliseconds or longer, DispatchSemaphore is the thing to use.
This extension is just to make using it easier and safer to use.
*/
extension os_unfair_lock
{
mutating func withLock<R>(block: () throws -> R) rethrows -> R
{
os_unfair_lock_lock(&self)
defer { os_unfair_lock_unlock(&self) }
return try block()
}
}
fileprivate var fullScreenLock = os_unfair_lock()
public fileprivate(set) var isFullScreen: Bool = false
// Call this function in the app delegate's applicationDidFinishLaunching method
func initializeFullScreenDetection()
{
_ = NotificationCenter.default.addObserver(
forName: NSWindow.willEnterFullScreenNotification,
object: nil,
queue: nil)
{ _ in
fullScreenLock.withLock { isFullScreen = true }
}
_ = NotificationCenter.default.addObserver(
forName: NSWindow.willExitFullScreenNotification,
object: nil,
queue: nil)
{ _ in
fullScreenLock.withLock { isFullScreen = false }
}
}
Since observer closures can be run concurrently, I use os_unfair_lock to guard races on the _isFullScreen property. You could use DispatchSemaphore, though it's a bit heavy weight for just guarding a Boolean flag. Back when the question was first asked, OSSpinLock would have been the equivalent, but it's been deprecated since 10.12.
Just make sure to call initializeFullScreenDetection() in your application delegate's applicationDidFinishLaunching() method.
I'm running an alert dialog as a sheet. The problem is, I only want to continue program execution when the sheet gets an answer. So I added default modal code from Apple :
NSModalSession session = [NSApp beginModalSessionForWindow:aWindow];
for (;;)
if ([NSApp runModalSession:session] != NSRunContinuesResponse)
break;
[NSApp endModalSession:session];
This made my code very clean, but there is one problem : if I do this, the sheet won't get in front of the menu bar anymore (I was using NSStatusWindowLevel to get that effect).
Has anyone a solution for this? I want to avoid did-end-selectors since they make code very messy. Thanks!
I had the same issue and found that I needed to set the window level in the session loop for it to work. In your case something like:
NSModalSession session = [NSApp beginModalSessionForWindow:aWindow];
for (;;) {
[mySheet setLevel: NSStatusWindowLevel];
if ([NSApp runModalSession:session] != NSRunContinuesResponse)
break;
}
[NSApp endModalSession:session];
Compiling in XCode 3.1.1 for OSX 10.5.8 target, 32-bit and i386 build.
I have a modal run loop, running in NSWindow wloop and NSView vloop. The modal loop is started first. It starts, runs and stops as expected. Here's the start:
[NSApp runModalForWindow: wloop];
Then, when the user presses the left mouse button, I do this:
if (ticking == 0) // ticking is set to zero in its definition, so starts that way
{
ticking = 1; // don't want to do this more than once per loop
tickCounter = 0;
cuckCoo = [NSTimer scheduledTimerWithTimeInterval: 1.0f / 10.0f // 10x per second
target: self // method is here in masterView
selector: #selector(onTick:) // method
userInfo: nil // not used
repeats: YES]; // should repeat
}
Checking the return of the call, I do get a timer object, and can confirm that the timer call is made when I expect it to be.
Now, according to the docs, the resulting NSTimer, stored globally as "cuckCoo", should be added to the current run loop automagically. The current run loop is definitely the modal one - at this time other windows are locked out and only the window with the intended mouse action is taking messages.
The method that this calls, "onTick", is very simple (because I can't get it to fire), located in the vloop NSView code, which is where all of this is going on:
- (void) onTick:(NSTimer*)theTimer
{
tickCounter += 1;
NSLog(#"Timer started");
}
Then when it's time to stop the modal loop (which works fine, btw), I do this:
[cuckCoo invalidate];
[NSApp stop: nil];
ticking=0;
cuckCoo = NULL;
NSLog(#"tickCounter=%ld",tickCounter);
ticking and tickCounter are both global longs.
I don't get the NSLog message from within onTick, and tickCounter remains at zero as reported by the NSLog at the close of the runloop.
All this compiles and runs fine. I just never get any ticks. I'm at a complete loss. Any ideas, anyone?
The problem is related to this statement "The current run loop is definitely the modal one". In Cocoa, each thread has at most one runloop, and each runloop can be run in a variety of "modes". Typical modes are default, event tracking, and modal. Default is the mode the loop normally runs in, while event tracking is typically used to track a drag session of the mouse, and modal is used for things like modal panels.
When you invoke -[NSTimer scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:] it does schedule the timer immediately, but it only schedules it for the default runloop mode, not the modal runloop mode. The idea behind this is that the app generally shouldn't continue to run behind a modal panel.
To create a timer that fires during a modal runloop, you can use -[NSTimer initWithFireDate:interval:target:selector:userInfo:repeats:] and then -[NSRunLoop addTimer:forMode:].
The answer specific to...
[NSApp runModalForWindow: wloop];
...is, after the modal run loop has been entered:
NSRunLoop *crl;
cuckCoo = [NSTimer timerWithTimeInterval: 1.0 / 10
target: self
selector: #selector(onTick:)
userInfo: nil
repeats:YES];
crl = [NSRunLoop currentRunLoop];
[crl addTimer: cuckCoo forMode: NSModalPanelRunLoopMode];
(crl obtained separately for clarity) Where the onTick method has the form:
- (void) onTick:(NSTimer*)theTimer
{
// do something tick-tocky
}
Can anyone explain with really clear use cases what the purpose of dispatch_sync in GCD is for? I can't understand where and why I would have to use this.
Thanks!
You use it when you want to execute a block and wait for the results.
One example of this is the pattern where you're using a dispatch queue instead of locks for synchronization. For example, assume you have a shared NSMutableArray a, with access mediated by dispatch queue q. A background thread might be appending to the array (async), while your foreground thread is pulling the first item off (synchronously):
NSMutableArray *a = [[NSMutableArray alloc] init];
// All access to `a` is via this dispatch queue!
dispatch_queue_t q = dispatch_queue_create("com.foo.samplequeue", NULL);
dispatch_async(q, ^{ [a addObject:something]; }); // append to array, non-blocking
__block Something *first = nil; // "__block" to make results from block available
dispatch_sync(q, ^{ // note that these 3 statements...
if ([a count] > 0) { // ...are all executed together...
first = [a objectAtIndex:0]; // ...as part of a single block...
[a removeObjectAtIndex:0]; // ...to ensure consistent results
}
});
First understand its brother dispatch_async
//Do something
dispatch_async(queue, ^{
//Do something else
});
//Do More Stuff
You use dispatch_async to create a new thread. When you do that, the current thread will not stop. That means //Do More Stuff may be executed before //Do something else finish
What happens if you want the current thread to stop?
You do not use dispatch at all. Just write the code normally
//Do something
//Do something else
//Do More Stuff
Now, say you want to do something on a DIFFERENT thread and yet wait as if and ensure that stuffs are done consecutively.
There are many reason to do this. UI update, for example, is done on main thread.
That's where you use dispatch_sync
//Do something
dispatch_sync(queue, ^{
//Do something else
});
//Do More Stuff
Here you got //Do something //Do something else and //Do More stuff done consecutively even though //Do something else is done on a different thread.
Usually, when people use different thread, the whole purpose is so that something can get executed without waiting. Say you want to download large amount of data but you want to keep the UI smooth.
Hence, dispatch_sync is rarely used. But it's there. I personally never used that. Why not ask for some sample code or project that does use dispatch_sync.
dispatch_sync is semantically equivalent to a traditional mutex lock.
dispatch_sync(queue, ^{
//access shared resource
});
works the same as
pthread_mutex_lock(&lock);
//access shared resource
pthread_mutex_unlock(&lock);
David Gelhar left unsaid that his example will work only because he quietly created serial queue (passed NULL in dispatch_queue_create what is equal to DISPATCH_QUEUE_SERIAL).
If you wish create concurrent queue (to gain all of multithread power), his code will lead to crash because of NSArray mutation (addObject:) during mutation (removeObjectAtIndex:) or even bad access (NSArray range beyond bounds). In that case we should use barrier to ensure exclusive access to the NSArray while the both blocks run. Not only does it exclude all other writes to the NSArray while it runs, but it also excludes all other reads, making the modification safe.
Example for concurrent queue should look like this:
NSMutableArray *a = [[NSMutableArray alloc] init];
// All access to `a` is via this concurrent dispatch queue!
dispatch_queue_t q = dispatch_queue_create("com.foo.samplequeue", DISPATCH_QUEUE_CONCURRENT);
// append to array concurrently but safely and don't wait for block completion
dispatch_barrier_async(q, ^{ [a addObject:something]; });
__block Something *first = nil;
// pop 'Something first' from array concurrently and safely but wait for block completion...
dispatch_barrier_sync(q, ^{
if ([a count] > 0) {
first = [a objectAtIndex:0];
[a removeObjectAtIndex:0];
}
});
// ... then here you get your 'first = [a objectAtIndex:0];' due to synchronised dispatch.
// If you use async instead of sync here, then first will be nil.
If you want some samples of practical use look at this question of mine:
How do I resolve this deadlock that happen ocassionally?
I solve it by ensuring that my main managedObjectContext is created on the main thread. The process is very fast and I do not mind waiting. Not waiting means I will have to deal with a lot of concurency issue.
I need dispatch_sync because some code need to be done on main thread, which is the different thread than the one where to code is being executed.
So basically if you want the code to
1. Proceed like usual. You don't want to worry about race conditions. You want to ensure that the code is completed before moving on.
2. Done on a different thread
use dispatch_sync.
If 1 is violated, use dispatch_async. If 2 is violated just write the code like usual.
So far, I only do this once, namely when something need to be done on main thread.
So here's the code:
+(NSManagedObjectContext *)managedObjectContext {
NSThread *thread = [NSThread currentThread];
//BadgerNewAppDelegate *delegate = [BNUtilitiesQuick appDelegate];
//NSManagedObjectContext *moc = delegate.managedObjectContext;
if ([thread isMainThread]) {
//NSManagedObjectContext *moc = [self managedObjectContextMainThread];
return [self managedObjectContextMainThread];
}
else{
dispatch_sync(dispatch_get_main_queue(),^{
[self managedObjectContextMainThread];//Access it once to make sure it's there
});
}
// a key to cache the context for the given thread
NSMutableDictionary *managedObjectContexts =[self thread].managedObjectContexts;
#synchronized(self)
{
if ([managedObjectContexts objectForKey:[self threadKey]] == nil ) {
NSManagedObjectContext *threadContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
threadContext.parentContext = [self managedObjectContextMainThread];
//threadContext.persistentStoreCoordinator= [self persistentStoreCoordinator]; //moc.persistentStoreCoordinator;// [moc persistentStoreCoordinator];
threadContext.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy;
[managedObjectContexts setObject:threadContext forKey:[self threadKey]];
}
}
return [managedObjectContexts objectForKey:[self threadKey]];
}
dispatch_sync is mainly used inside dispatch_async block to perform some operations on main thread(like update ui).
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//Update UI in main thread
dispatch_sync(dispatch_get_main_queue(), ^{
self.view.backgroundColor = color;
});
});
Here's a half-way realistic example. You have 2000 zip files that you want to analyze in parallel. But the zip library isn't thread-safe. Therefore, all work that touches the zip library goes into the unzipQueue queue. (The example is in Ruby, but all calls map directly to the C library. "apply", for example, maps to dispatch_apply(3))
#!/usr/bin/env macruby -w
require 'rubygems'
require 'zip/zipfilesystem'
#unzipQueue = Dispatch::Queue.new('ch.unibe.niko.unzipQueue')
def extractFile(n)
#unzipQueue.sync do
Zip::ZipFile.open("Quelltext.zip") { |zipfile|
sourceCode = zipfile.file.read("graph.php")
}
end
end
Dispatch::Queue.concurrent.apply(2000) do |i|
puts i if i % 200 == 0
extractFile(i)
end
I've used dispatch sync when inside an async dispatch to signal UI changes back to the main thread.
My async block holds back only a little and I know the main thread is aware of the UI changes and will action them. Generally used this in a processing block of code that takes some CPU time but I still want to action UI changes from within that block. Actioning the UI changes in the async block is useless as UI, I believe, runs on the main thread. Also actioning them as secondary async blocks, or a self delegate, results in the UI only seeing them a few seconds later and it looks tardy.
Example block:
dispatch_queue_t myQueue = dispatch_queue_create("my.dispatch.q", 0);
dispatch_async(myQueue,
^{
// Do some nasty CPU intensive processing, load file whatever
if (somecondition in the nasty CPU processing stuff)
{
// Do stuff
dispatch_sync(dispatch_get_main_queue(),^{/* Do Stuff that affects UI Here */});
}
});
I have a custom NSView (it's one of many and they all live inside an NSCollectionView — I don't think that's relevant, but who knows). When I click the view, I want it to change its selection state (and redraw itself accordingly); when I double-click the view, I want it to pop up a larger preview window for the object that was just double-clicked.
My first looked like this:
- (void)mouseUp: (NSEvent *)theEvent {
if ([theEvent clickCount] == 1) [model setIsSelected: ![model isSelected]];
else if ([theEvent clickCount] == 2) if ([model hasBeenDownloaded]) [mainWindowController showPreviewWindowForPicture:model];
}
which mostly worked fine. Except, when I double-click the view, the selection state changes and the window pops up. This is not exactly what I want.
It seems like I have two options. I can either revert the selection state when responding to a double-click (undoing the errant single-click) or I can finagle some sort of NSTimer solution to build in a delay before responding to the single click. In other words, I can make sure that a second click is not forthcoming before changing the selection state.
This seemed more elegant, so it was the approach I took at first. The only real guidance I found from Google was on an unnamed site with a hyphen in its name. This approach mostly works with one big caveat.
The outstanding question is "How long should my NSTimer wait?". The unnamed site suggests using the Carbon function GetDblTime(). Aside from being unusable in 64-bit apps, the only documentation I can find for it says that it's returning clock-ticks. And I don't know how to convert those into seconds for NSTimer.
So what's the "correct" answer here? Fumble around with GetDblTime()? "Undo" the selection on a double-click? I can't figure out the Cocoa-idiomatic approach.
Delaying the changing of the selection state is (from what I've seen) the recommended way of doing this.
It's pretty simple to implement:
- (void)mouseUp:(NSEvent *)theEvent
{
if([theEvent clickCount] == 1) {
[model performSelector:#selector(toggleSelectedState) afterDelay:[NSEvent doubleClickInterval]];
}
else if([theEvent clickCount] == 2)
{
if([model hasBeenDownloaded])
{
[NSRunLoop cancelPreviousPerformRequestsWithTarget: model];
[mainWindowController showPreviewWindowForPicture:model];
}
}
}
(Notice that in 10.6, the double click interval is accessible as a class method on NSEvent)
If your single-click and double-click operations are really separate and unrelated, you need to use a timer on the first click and wait to see if a double-click is going to happen. That is true on any platform.
But that introduces an awkward delay in your single-click operation that users typically don't like. So you don't see that approach used very often.
A better approach is to have your single-click and double-click operations be related and complementary. For example, if you single-click an icon in Finder it is selected (immediately), and if you double-click an icon it is selected and opened (immediately). That is the behavior you should aim for.
In other words, the consequences of a single-click should be related to your double-click command. That way, you can deal with the effects of the single-click in your double-click handler without having to resort to using a timer.
Personally, I think you need to ask yourself why you want this non-standard behaviour.
Can you point to any other application which treats the first click in a double-click as being different from a single-click? I can't think of any...
Add two properties to your custom view.
// CustomView.h
#interface CustomView : NSView {
#protected
id m_target;
SEL m_doubleAction;
}
#property (readwrite) id target;
#property (readwrite) SEL doubleAction;
#end
Overwrite the mouseUp: method in your custom view.
// CustomView.m
#pragma mark - MouseEvents
- (void)mouseUp:(NSEvent*)event {
if (event.clickCount == 2) {
if (m_target && m_doubleAction && [m_target respondsToSelector:m_doubleAction]) {
[m_target performSelector:m_doubleAction];
}
}
}
Register your controller as the target with an doubleAction.
// CustomController.m
- (id)init {
self = [super init];
if (self) {
// Register self for double click events.
[(CustomView*)m_myView setTarget:self];
[(CustomView*)m_myView setDoubleAction:#selector(doubleClicked:)];
}
return self;
}
Implement what should be done when a double click happens.
// CustomController.m
- (void)doubleClicked:(id)sender {
// DO SOMETHING.
}
#Dave DeLong's solution in Swift 4.2 (Xcode 10, macOS 10.13), amended for use with event.location(in: view)
var singleClickPoint: CGPoint?
override func mouseDown(with event: NSEvent) {
singleClickPoint = event.location(in: self)
perform(#selector(GameScene.singleClickAction), with: nil, afterDelay: NSEvent.doubleClickInterval)
if event.clickCount == 2 {
RunLoop.cancelPreviousPerformRequests(withTarget: self)
singleClickPoint = nil
//do whatever you want on double-click
}
}
#objc func singleClickAction(){
guard let singleClickPoint = singleClickPoint else {return}
//do whatever you want on single-click
}
The reason I'm not using singleClickAction(at point: CGPoint) and calling it with: event.location(in: self) is that any point I pass in - including CGPoint.zero - ends up arriving in the singleClick Action as (0.0, 9.223372036854776e+18). I will be filing a radar for that, but for now, bypassing perform is the way to go. (Other objects seem to work just fine, but CGPoints do not.)