Our application was working fine in iOS 16, but after upgrading to iOS 17.1.1, we see a 100% reproducible crash when generating a cell in the [UITableViewDataSource tableView: cellForRowAtIndexPath:] callback for a particular table. I've only found a single table so far where it crashes.
This is the line of code where it crashes:
ItemContentTableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier forIndexPath:indexPath];
The crash occurs on the first call. Since it only crashes in this one table, I imagine it's somehow related to the particulars of the cell content layout, but as far as I can see, there's nothing spectacular going on there.
Any ideas?? Thanks.
Objective-C
RSS for tagObjective-C is a programming language for writing iOS, iPad OS, and macOS apps.
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I have a need to list all known audio/image file types in a planned app.
What I have known so far:
images
.apng
.avi, .avif
.gif
.jpg, .jpeg, .jfif, .pjpeg, .pjp
.png
.svg
.webp
audio
.aif
.cda
.mid, .midi
.mp3
.mpa
.ogg
.wav
.wma
What are the missing ones?
I have an application that uses Accessibility APIs to determine if a browser tab with website content is present by checking for the AXWebArea role element. However, some users have reported that the app is not working after a recent update. When I check for permission using the following code, the result is YES, but the app still cannot detect the AXWebArea element in the browser though other elements like AXButton were there:
NSDictionary *options = @{(__bridge id)kAXTrustedCheckOptionPrompt : @YES};
NSLog(@“%d”, AXIsProcessTrustedWithOptions((__bridge CFDictionaryRef)options));
The issue is resolved when the app is removed and re-added to the Accessibility permissions list in the System settings. I would appreciate a detailed explanation of what could be causing this issue.
I allow users to choose a font to use throughout the app, then display text using that font in 3 different ways:
As the default body font of an HTML document displayed in a WKWebView.
Used to create an NSAttributedString then displayed in an NSTextField.
Used as the body font of a very small HTML document (2-3 lines), converted to NSAttributedString, then displayed in an NSTextField.
My code has been working fine for years, but starting with the release of Sonoma (macOS 14), any text that is converted from HTML to NSAttributedString displays as all "question marks in boxes" for each character. This happens when certain fonts are used. In particular I've seen it with Calibri, Candara, and SF Pro. Calibri and Candara are Microsoft fonts and I think are distributed with MS Office. SF Pro is an Apple font.
There could be others; I haven't done an exhaustive check. What I can tell you is that this has been working fine literally until a couple weeks ago when customers began installing macOS 14. If they go into my app and select a different font (such as Arial or Times New Roman) everything works fine. It is only certain fonts that don't work, and those fonts work when used as the body font of an HTML document in WKWebView and when used as the font for a new NSAttributedString. They just don't work if you make a little HTML document with the font selected as the body font, then convert to NSAttributedString.
Here's the code that worked up until macOS 14:
NSString *htmlString = @"<!DOCTYPE html>"
"<html>"
"<head>"
"<style>"
"body { font-family: 'Candara', serif; font-size: 14px; }"
"</style>"
"</head>"
"<body>"
"This won't display right."
"</body>"
"</html>";
NSData *htmlData = [htmlString dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *options = @{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType,
NSCharacterEncodingDocumentAttribute: @(NSUTF8StringEncoding)};
NSError *error;
NSAttributedString *attributedString = [[NSAttributedString alloc] initWithData:htmlData
options:options
documentAttributes:nil
error:&error];
Note the fallback of "serif" — that doesn't matter. you get all undefined characters and the fallback font is not used. It's as if the renderer really believes the font is usable, but it isn't.
as I open the pop-up menu and move the mouse before that opened, MouseEntered Event and MouseExited Event are called when mouse moved.
The following trackingAreas options are inclued in the view in pop-up area.
NSTrackingInVisibleRect, NSTrackingMouseEnteredAndExited, NSTrackingMouseMoved, NSTrackingActiveInKeyWindow
LocationInWindow of MouseExitedEvent seem to be incorrect.
This problems does not occur in the following cases.
Do not move the mouse until the popup is fully opened.
Left mouse button down on pop-up area.
Move the mouse out of the pop-up area.
This issue occurs in Sonoma(MacOS14.0) and later.
I would like to know if this is a code issue or a bug in the OS Version.
AppDelegate.h
#import <Cocoa/Cocoa.h>
@interface ViewInPopup : NSView {
NSString* resultStr;
NSUInteger enteredCount;
NSPoint lastEnteredPos;
NSUInteger exitedCount;
NSPoint lastExitedPos;
NSUInteger movedCount;
NSPoint lastMovedPos;
NSTrackingArea* trackingArea;
}
@end
@interface AppDelegate : NSObject <NSApplicationDelegate> {
NSMenu* myMenu;
ViewInPopup* viewInPopup;
}
- (IBAction)onClickButton:(id)sender;
@end
AppDelegate.mm
#import "AppDelegate.h"
@interface ViewInPopup ()
- (void)showResult:(NSEvent*)event;
@end
@implementation ViewInPopup
- (id)initWithFrame:(NSRect)frameRect
{
self = [super initWithFrame:frameRect];
[self setWantsLayer:TRUE];
[[self layer] setBackgroundColor:[NSColor redColor].CGColor];
return self;
}
- (void)drawRect:(NSRect)dirtyRect
{
[super drawRect:dirtyRect];
[resultStr drawInRect:[self bounds] withAttributes:nil];
}
- (void)updateTrackingAreas
{
if (trackingArea) {
[self removeTrackingArea:trackingArea];
}
NSTrackingAreaOptions options = NSTrackingInVisibleRect | NSTrackingMouseEnteredAndExited | NSTrackingMouseMoved | NSTrackingActiveInKeyWindow;
trackingArea = [[NSTrackingArea alloc] initWithRect:[self bounds] options:options owner:self userInfo:nil];
[self addTrackingArea:trackingArea];
[super updateTrackingAreas];
}
- (void)mouseEntered:(NSEvent *)event
{
[self showResult:event];
[super mouseEntered:event];
}
- (void)mouseExited:(NSEvent *)event
{
[self showResult:event];
[super mouseExited:event];
}
- (void)mouseMoved:(NSEvent *)event
{
[self showResult:event];
[super mouseMoved:event];
}
- (void)showResult:(NSEvent*)event
{
NSString* eventTypeStr = @"";
switch (event.type) {
case NSEventTypeMouseEntered:
eventTypeStr = @"Entered";
[[self layer] setBackgroundColor:[NSColor redColor].CGColor];
if (enteredCount >= NSUIntegerMax) {
enteredCount = 0;
} else {
enteredCount++;
}
lastEnteredPos = event.locationInWindow;
break;
case NSEventTypeMouseExited:
eventTypeStr = @"Exited";
[[self layer] setBackgroundColor:[NSColor blueColor].CGColor];
if (exitedCount >= NSUIntegerMax) {
exitedCount = 0;
} else {
exitedCount++;
}
lastExitedPos = event.locationInWindow;
break;
case NSEventTypeMouseMoved:
eventTypeStr = @"Moved";
[[self layer] setBackgroundColor:[NSColor greenColor].CGColor];
if (movedCount >= NSUIntegerMax) {
movedCount = 0;
} else {
movedCount++;
}
lastMovedPos = event.locationInWindow;
break;
default:
return;
}
resultStr = [NSString stringWithFormat:@"LastEventType:%@\n\nEnteredCount:%ld\nLastEnteredPosition:(%f, %f)\n\nExitedCount:%ld\nLastExitedPosition:(%f %f)\n\nMovedCount:%ld\nLastMovedPosition:(%f, %f)", eventTypeStr, enteredCount, lastEnteredPos.x, lastEnteredPos.y, exitedCount, lastExitedPos.x, lastExitedPos.y, movedCount, lastMovedPos.x, lastMovedPos.y];
[self setNeedsDisplay:YES];
}
@end
@interface AppDelegate ()
@property (strong) IBOutlet NSWindow *window;
@end
@implementation AppDelegate
- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
// Insert code here to initialize your application
myMenu = [[NSMenu alloc] init];
NSMenuItem* item = [[NSMenuItem alloc] init];
[myMenu addItem:item];
viewInPopup = [[ViewInPopup alloc] initWithFrame:NSMakeRect(0, 0, 300, 300)];
[item setView:viewInPopup];
}
- (void)applicationWillTerminate:(NSNotification *)aNotification {
// Insert code here to tear down your application
}
- (BOOL)applicationSupportsSecureRestorableState:(NSApplication *)app {
return YES;
}
- (IBAction)onClickButton:(id)sender
{
[myMenu popUpMenuPositioningItem:nil atLocation:NSZeroPoint inView:(NSView*)sender];
}
@end
In the context of a system utility that reports OS stats periodically, the security type for a connected WiFi network could be obtained with Core WLAN via CWInterface.security.
This used to work up to Ventur; howver, after upgrading to Sonoma, cwInterface.security now returns kCWSecurityUnknown.
In other posts, I have read about changes in how Core WLAN works which are related to Sonoma.
How can I determine the security type for a connected WiFi network on Sonoma? It would be preferable if the suggested approach would also work on previous macOS versions as well.
Many thanks in advance! :-)
Hi, I work on a game for iOS and the framerate decreases progressively when the debugger is attached.
Running it for 2mins, it went from 30 to 1 FPS while rendering a simple static scene.
I narrowed it down to a call to dispatch_async_f which takes longer to execute over time.
clock_t t1 = clock();
dispatch_async_f(queue, context, function);
clock_t t2 = clock();
double duration = (double)(t2 -t1)/(double)CLOCKS_PER_SEC;
Dodumentation says dispatch_async_f is supposed to return immediatly.
So what could explain duration to increases in debug? Am i measuring this incorrectly?
The game is written in mixed C++ and ObjC. It uses Metal as graphic API and GCD for dispatching jobs.
I have Xcode 13.4.1 and test on an iPhone 13 Pro with iOS 15.7.
Thanks.
I am trying to develop a plug in for motion in Objective-c using the FxPlug template and so far I have been having issues with getting "NSOpenPanel" to be called from a push button in order to get a file dialog window, similar to the "File" generator present in Motion.
[paramAPI addPushButtonWithName: @"MIDI file"
parameterID: 1
selector: @selector(MIDI_func)
parameterFlags: kFxParameterFlag_DEFAULT]
I have tried to call NSOpenPanel through "dispatch_async" so that it would run on the main thread and thus not crash but when I press the button it appears not to work
- (void)MIDI_func {
NSLog(@"Button pressed");
dispatch_async(dispatch_get_main_queue(), ^{
NSOpenPanel* openDlg = [NSOpenPanel openPanel];
[openDlg setCanChooseFiles:YES];
[openDlg setAllowsMultipleSelection:NO];
[openDlg setCanChooseDirectories:NO];
if ([openDlg runModal] == NSModalResponseOK) {
NSArray* urls = [openDlg URLs];
for(NSInteger i = 0; i < [urls count]; i++ ) {
NSString* url = [urls objectAtIndex:i];
NSLog(@"Url: %@", url);
}
}
});
}
How can I achieve this or is there a function in the FxPlug SDK that will let me open a file dialog from the host application?
I've been seeing this crash happening for a few years now. It's rare and unreproducible. The App's storyboard is large and it can occur on any segue and randomly it seems
Could not find a navigation controller for segue 'some-segue-on-storyboard'. Push segues can only be used when the source controller is managed by an instance of UINavigationController.
I've tried various things to prevent it. Double checked it was on the main thread to keep the UI happy and assumed all this time that it was just an iOS glitch/bug that Apple would get around to fixing.
That or it is a side effect of low memory.
Anyone got any suggestions for how to fix or what to investigate?
I create a protocol that had, among other things:
@objc func setList(_: [MyType], withReply: @escaping (Error?) -> Void)
The daemon part is in Swift, while the calling part is in Objective-C. Because why not? (Actually, because the calling part has to deal with C++ code, so that's ObjC++; however, I wanted the stronger typing and runtime checking for the daemon part, so I wrote it in Swift.) The ObjC part uses NSArray<MyType*>.
I set up an NSXPCConnection link, and create a (synchronous) proxy with the right protocol name. But when I try to do the XPC setList call, I get an error. I assume that's because it doesn't like the signature. (Surely this is logged somewhere? I couldn't find it, if so. 😩) But... if I have a signature of @objc func addItem(_: MyType, withReply: @escaping (Error?) -> Void), then it works. So I assume it's the array. (Oh, I've also tried it without the @objc; the protocol itself is defined as @objc.)
I've tried changing to protocol signature to using NSArray, but same thing.
Hi there,
I'm working on an app that contains a mini system monitoring utility. I would like to list the top CPU-using processes.
As Quinn “The Eskimo!” has repeatedly cautioned, relying on private frameworks is just begging for maintenance effort in the future. Ideally, I want to go through public headers/frameworks.
I've gone to great lengths to try to find this information myself, and at this point I'm just struggling. I detail my research below.
Any pointers in the right direction would be much appreciated!
Attempts
Libproc
First I looked at libproc. Using proc_pidinfo with PROC_PIDTHREADINFO, I'm able to get each thread of an app, with its associated CPU usage percentage. Summing these, I could get the total for an app.
Unfortunately, this has two downsides:
Listing a table of processes now takes O(proces_count) rather than just O(process_count), and causes way more syscalls to be made
It doesn't work for processes owned by other users. Perhaps running as root could alleviate that, but that would involve making a priviliedged helper akin to the existing sysmond that Activity Monitor.app uses. I'm a little scared of that, because I don't want to put my users at risk.
Sysctl
Using the keys [CTL_KERN, KERN_PROC, KERN_PROC_PID, someProcessID], I'm able to get a kinfo_proc - https://github.com/apple-opensource/xnu/blob/24525736ba5b8a67ce3a8a017ced469abe101ad5/bsd/sys/sysctl.h#L750-L776 instance. Accessing its .kp_proc - https://github.com/apple-opensource/xnu/blob/24525736ba5b8a67ce3a8a017ced469abe101ad5/bsd/sys/proc.h#L96-L150.p_pctcpu - https://github.com/apple-opensource/xnu/blob/24525736ba5b8a67ce3a8a017ced469abe101ad5/bsd/sys/proc.h#L123 looked really promising, but that value is always zero.
Digging deeper, I found the kernel code that fills this struct in (fill_user64_externproc - https://github.com/apple-opensource/xnu/blob/c76cff20e09b8d61688d1c3dfb8cc855cccb93ad/bsd/kern/kern_sysctl.c#L1121-L1168). The assignment of p_pctcpu - https://github.com/apple-opensource/xnu/blob/c76cff20e09b8d61688d1c3dfb8cc855cccb93ad/bsd/kern/kern_sysctl.c#L1149 is in a conditional region, relying on the _PROC_HAS_SCHEDINFO_ flag. Disassembling the kernel on my mac, I could confirm that the assignment of that field never happens (thus _PROC_HAS_SCHEDINFO_ wasn't set during compilation, and the value will always stay zero)
Reverse engineering Activity Monitor.app
Activity Monitor.app makes proc_info and sysctl system calls, but from looking at the disassembly, it doesn't look like that's where its CPU figures come from. From what I can tell, it's using private functions from /usr/lib/libsysmon.dylib.
That's a user library which wraps an XPC connection to sysmond (/usr/libexec/sysmond), allowing you to create requests (sysmon_request_create), add specific attributes you want to retrieve (sysmon_request_add_attribute), and then functions to query that data out (sysmon_row_get_value).
Getting the data "striaght from the horses mouth" like this sounds ideal. But unfortunately, the only documentation/usage I can find of sysmond is from bug databases demonstrating a privilege escalation vulnerability lol. There are some partial reverse engineered header files floating around, but they're incomplete, and have the usual fragility/upkeep issues associated with using private APIs.
On one hand, I don't want to depend on a private API, because that takes a lot of time to reverse engineer, keep up with changes, etc. On the other, making my own similar privileged helper would be duplicating effort, and expose a bigger attack surface. Needless to say, I have no confidence in being able to make a safer privileged helper than Apple's engineers lol
Reverse engineering iStat Menus
Looks like they're using proc_pid_rusage - https://github.com/apple-opensource/xnu/blob/24525736ba5b8a67ce3a8a017ced469abe101ad5/libsyscall/wrappers/libproc/libproc.h#L103-L108 .
However, I don't know how to convert the cpu_*_time fields of the resulting struct rusage_info_v4 - https://github.com/apple-opensource/xnu/blob/24525736ba5b8a67ce3a8a017ced469abe101ad5/bsd/sys/resource.h#L306-L343 to compute a "simple" percentage. Even if I came up with some formula that produces plausible looking results, I have no real guarantee it's correct or equivalent to what Activity Monitor shows.