Re: Delayed -dealloc occurs on worker thread if object is working. How?
detachNewThreadSelector:target:withObject: retains both the target and the
object.
-BJ
On Wed, Jun 2, 2010 at 11:39 AM, Jerry Krinock je...@ieee.org wrote:
I allocate an object Foo on the main thread. Then I spin off a secondary
thread and give it a long task to do there, but immediately release the
object, on the main thread. I expect that the -release invoke -dealloc
immediately, on the main thread. To my amazement, the object is not
deallocced until the task is finished, and to my further amazement, the
dealloc method runs on the secondary thread.
Someone please enlighten me. This is Mac OS 10.6.3, Objective-C garbage
collection = unsupported.
Jerry Krinock
#import Cocoa/Cocoa.h
@interface Foo : NSObject {
}
@end
@implementation Foo
- (void)sleep5 {
NSLog(@Sleeping for 5 on secondary thread) ;
sleep(5) ;
}
- (void)dealloc {
[super dealloc] ;
NSLog(@Did dealloc a Foo) ;
}
@end
int main(int argc, char *argv[]) {
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init] ;
Foo* foo = [[Foo alloc] init] ;
[NSThread detachNewThreadSelector:@selector(sleep5)
toTarget:foo
withObject:nil] ;
[foo release] ;
sleep(10) ;
NSLog(@Terminating) ;
[pool release] ;
return 0 ;
}
RESULT:
10:23:00.879 LittleTool[83071:1103] Sleeping for 5 on secondary thread
10:23:05.884 LittleTool[83071:1103] Will dealloc a Foo
10:23:05.885 LittleTool[83071:1103] Did dealloc a Foo
10:23:10.879 LittleTool[83071:80f] Terminating
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Notification of unmount events
I'm trying to detect disk mount/unmount notifications from a Foundation tool. Previous questions to this list (e.g. http://lists.apple.com/archives/cocoa-dev/2007/Jan/msg01170.html) on this topic have suggested the DiskArbitration framework, which I am using. The DiskArbitration framework has a number of callbacks. However, none seems to do what I'm wanting to do. DiskAppeared callback: - Called when a volume is attached, even if not mounted. That is, if I have 2 partitions on an external drive but only 1 mounted, I will still hear about both. DiskDisappeared callback: - Called when a volume is physically gone, not just unmounted. If I unmount one volume on my external drive and leave the other mounted, I won't hear about the unmount through this callback. DiskDescriptionChanged callback: - I can register for changes on the DAVolumePath key, and this works if the volume is a physical external drive. If it's a network drive, though, then the description never *changes*; it begins life with the DAVolumePath key correctly populated. Between DiskAppeared, DiskDisappeared and DiskDescription I can usually be notified of all disk mount events, but I get some duplication, and in general it feels very hacked together. DiskMountApproval callback: - Notifies me that someone *wants* to mount the volume, but does not guarantee that the disk was actually mounted. DiskUnmountApproval callback: - Notifies me that someone *wants* to unmount the volume, but does not guarantee that the volume was actually unmounted. In one case I'm working on right now, I'll have an external drive attached. On reboot, I register for the mountApproval and unmountApproval callbacks. The volume is mounted and then I immediately get an unmountApproval callback. If I treat this callback as a sign that the drive actually *was* unmounted, then I would assume that the volume is being mounted and immediately unmounted (within milliseconds) upon startup. That is clearly not the case, since the volume is still attached when I get up into my login session. This is in a LaunchDaemon, and the code has been running the whole time without any further DiskArbitrationCallbacks. Previous answers (including the one I linked to) have suggested looking at the code of the disktool utility. It correctly handles situations like this. It appears, though, that it is using additional information. disktool.c includes DiskArbitrationPrivate.hhttp://www.opensource.apple.com/source/DiskArbitration/DiskArbitration-183/DiskArbitration/DiskArbitrationPrivate.h, and calls functions defined there including DiskArbRegisterCallback_UnmountPreNotification and DiskArbRegisterCallback_UnmountPostNotification. That PostNotification part looks like what I need in the case of unmounting. Unfortunately, it's in a private header. I could, of course, copy that header into my project, but I would have no guarantee that the API would be stable between Leopard and Snow Leopard, for example. And even though the header is open source and publicly available, I think it still falls into the category of a private API, and thus I'd rather avoid that. The context of all this, since I'm sure someone will ask, is a backup daemon (a LaunchDaemon) which is keeping track of what files are dirty; when a volume is mounted, I need to check to see whether any files on that volume match my rules of what to back up. When a volume is unmounted, I need to update some internal state to stop tracking those files. So, my question: is there a better way to be notified of disk mount/unmount events? If there's a better list for such questions, please feel free to direct me there. I searched on lists.apple.com, and everything relating to DiskArbitration was showing up on Cocoa-dev. Thanks, -BJ Homer ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: User-space threads and NSAutoreleasePool
On Wed, Mar 17, 2010 at 11:47 PM, Greg Guerin glgue...@amug.org wrote: Two main questions come to mind: Q1. What are you trying to accomplish? Q2. Why do you think this would work? More on Q1: You said you need user-space threads, but you gave no reason or rationale. If it's because you need 500 threads, then why do you need 500 threads? Exactly what are you trying to accomplish? Q1: What am I trying to accomplish? In this particular case, I'm working on an application that sends very large HTTP PUT requests over an HTTP connection in a pipelined fashion. For performance reasons, the server prefers to delay acknowledgement of these files until it can process them in large groups. (Before it can send an ack, it must update a database. Doing 400-500 single updates is far slower than doing one transaction updating 400-500 records.) Hence, we pipeline the HTTP requests, starting transfer of the second before the first one is finished. There are a large number of servers that don't handle pipelining, but we'll only we talking to one particular server, and we know it does. NSURLConnection does not (according to various mailing list messages) implement pipelining, allegedly due to the lack of server support. There's some suggestion that CFHTTPStream does support pipelining, but there's little to no documentation about it, and I don't know if it will handle 500 at once. If you can use user-space threads, this becomes simple; you send the first file, and then when you're waiting for the ACK, you swap out and let another file start sending. When the ack is received, the first user-thread is rescheduled. We've developed an extremely high-performance cross-platform library that handles all the scheduling directly. Then we've built another library around that that handles all the particulars of our server protocol. At the moment, I'm converting our OS X client to use this library. That's my immediate motivation; if I can use an existing library, I'll save a large amount of time, get a big performance boost, and have less code to test. To a large extent, it is already working. More on Q2: The ucontext(3) functions appear to me to be more intended for signal-handling, specifically for alt-signal-stack handling. The nature of signals is that they eventually return (nested), they don't work in a round-robin or any other scheduling. That's not a question, just prep. The question is this: Are you sure the Objective-C runtime is compatible with ucontext user-threads? There are lots of things you can't do in signal-handlers, not even handlers written in plain C (ref: man sigaction, the list of safe functions). If you can't call malloc() in a signal-handler (and I'm pretty sure you can't), what do you expect to happen with your Objective-C user-threads, since object allocation is tied to malloc()? Q2: Why do I think this would work? Am I sure the Obj-C runtime is compatible with ucontext user-threads? No. There is, in general, relatively little information on use of ucontext user-threads on OS X. Mostly, it exists in man pages. So far the only issue I've run into is the autorelease pool issue mentioned previously, which isn't (I suspect) actually a runtime issue at all. There may be other issues, but that's part of the reason I'm asking on the list. I can work around the autorelease pool issue if I have to (by limiting my use of Objective-C objects and autorelease pools in such a way that I can guarantee correctness), but if there are other known issues, I'd love to hear about them. It's true that ucontext stuff is often used for signal handling, but that's not the only use case. My code does not relate to signal handling at all. As mentioned above, all this ucontext stuff happening in a cross-platform library. It's already running on Linux, where I suspect the malloc-in-signal-handlers restrictions equally apply. I've also had it running (to some extent) as well. In neither Linux nor my initial attempts on OS X have I seen anything to indicate that object allocation was not working. In fact, I have a fair amout of evidence that it is likely working just fine. If object allocation was failing or otherwise unstable, my code would be crashing all over the place, not just having autorelease pool issues. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
User-space threads and NSAutoreleasePool
Hi everyone,
Some setup, first. If you just want to jump to the question, jump to the
last paragraph.
OS X includes (as part of its UNIX heritage) functions for implementing
user-space threading. (See, for example, the man page on
swapcontexthttp://developer.apple.com/Mac/library/documentation/Darwin/Reference/ManPages/man3/swapcontext.3.html.)
This allows developers to swap out the current stack for another, in effect
allowing two threads of execution on a single thread. Using kernel-level
threads is, naturally, simpler, but due to the cost of kernel-level context
switches, they don't scale well. (You just can't run 500 threads at once
very well.) User-space threads require more programmer attention, certainly,
but also allow certain programming models that can't be done otherwise. For
example, they can be used for coroutines, cooperative threading, or all
sorts of esoteric-yet-sometimes-useful effects.
I say all that in an effort to avoid the frequent you're fighting the
frameworks responses. I'm well familiar with the frameworks, GCD, etc., and
in this particular case, user-space threads is what I need.
The problem is that when you call swapcontext() to switch the user-thread
running on a kernel-thread, the NSAutoreleasePool stack is not swapped out.
It remains rooted in thread-local storage. As a result, serious problems
result. Let me give an example.
- (void)doStuff {
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
// do some stuff that calls swapcontext()
[pool drain];
}
-doStuff calls swapcontext(), trusting that the other user-thread will
eventually call swapcontext() and restore the flow to this user-thread.
Further, assume that the second user-thread also allocates an autorelease
pool before returning. Despite being on separate user-threads, there is
still only one kernel-thread. Since the autorelease pool stack is in
(kernel-)thread-local storage, the second user-thread's pool goes on top of
the same stack:
Autorelease pool stack: pool_from_uthread1 - pool_from_uthread2
Now, when we swap back to the first user-thread, it will release its
autorelease pool. This, naturally, releases the second pool as well. When we
swap back to the second user-thread, anything that was autoreleased is now
dead and gone.
Okay, so that's the setup. Obviously, the problem is that the two user-space
threads are sharing an autorelease pool stack that is intended to be
thread-local. My question, then, is whether there exists a way to get and
set the autorelease pool stack, so that before calling swapcontext(), I
could put it in a state appropriate for this user-level thread? I assume it
is being stored in thread-local storage, but it's not in the NSThread
threadDictionary, which means it's probably set using pthread_setspecific.
Accessing that value would require the key used to store it, but naturally I
don't have access to that. So is there some existing function call that
allows such access?
Thanks for listening,
-BJ Homer
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Re: NSPredicate regex
I've found Reggy (http://reggyapp.com/) to be *extremely* useful in debugging regular expressions. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: iPhone: validate a NSString for US zipcode
Well, depends on what you mean by ordered. NSArray retains insertion order. NSSet does not. But NSSet may be sorting things on insertion (like you'd get with a binary tree structure), while NSArray cannot assume any particular order. So from the NSArray implementor's standpoint, the array is unordered. -BJ On Thu, Jan 7, 2010 at 2:52 PM, Dave DeLong davedel...@me.com wrote: That's backwards. NSArray is ordered; NSSet is not. Dave On Jan 7, 2010, at 2:44 PM, David Duncan wrote: Since NSArray is unordered I would not expect its containsObject to do better than O(n). If NSSet is an ordered container, it should be able to do O(lg n). ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Question about looping constructs
Branching from the Question about garbage collection thread
On Sun, Jan 3, 2010 at 11:40 AM, Bill Bumgarner b...@mac.com wrote:
If you are writing your own looping construct, you can call
objc_clear_stack(...) to clear the stack at appropriate times, typically
when the stack is as shallow as possible. Prior to Snow Leopard, writing
your own looping construct was relatively rare in Cocoa. With Snow
Leopard's addition of Grand Central Dispatch, writing your own looping
construct is actively discouraged (though, certainly, there are still
reasons to do so).
b.bum
I assume that when you say looping construct, you're not referring to
things like for, while, do-while, etc. Could you explain what you're talking
about? I'm guessing you mean run loops on detached threads, and if so, are
you referring to using custom input sources for threads? I've seen a fair
amount of code that detaches a thread to a method with a while(!done) { //
code here } structure. Is there a better way?
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Re: Stack-based C++ class to wrap NSAutoreleasePool
Does the stack-based idiom allow returning an autoreleased object? I'd
think you'd end up with code like this:
- (id)arrayWithStuff {
StackAutoreleasePool();
NSArray *array = [NSArray arrayWithObjects:obj1, obj2, etc, nil];
return array;
}
which would essentially translate into:
- (id)arrayWithStuff {
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSArray *array = [NSArray arrayWithObjects:obj1, obj2, etc, nil];
[pool release];
return array; // array is dead
}
Is there some reason why this would not happen?
-BJ
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Re: [iPhone] OS 3.0 and @synthesize AND @dynamic for the same property
On Thu, Nov 12, 2009 at 2:52 AM, Joerg Simon j_si...@mac.com wrote: Dear all other Cocoa Developers: In an app I am developing I have the following strange thing: [code in the .h file] @interface XY : CALayer BOOL _editing; ... @property (assign, getter = isEditing) BOOL editing; [/code] [code in the .m file] @synthesize editing = _editing; @dynamic editing; The @dynamic is entirely unnecessary; you should use @synthesize or @dynamic, but not both. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Multiple variable rules in for() statement
I believe this is actually independent of being in a for loop. Your first line corresponds to code like this: int i; i=0, int m=0; Which is syntactically incorrect. Your second example corresponds to this: int i; int m=0, i; Which is an attempt to re-declare i. So you're correct; you can't have both an old variable and a new variable in the for loop initialization. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Less verbose way to localize a string with a default value?
You can use the -s flag to genstrings to tell it to use your own prefix instead of NSLocalizedString. For example, passing -s MyString would catch calls to MyString(), MyStringFromTable(), MyStringWithDefaultValue(), etc. However, these functions must take the same arguments as the default NSLocalizedString macros, so you don't really gain much if you're just looking to reduce verbosity without changing functionality. More info here: http://developer.apple.com/Mac/library/documentation/Cocoa/Conceptual/LoadingResources/Strings/Strings.html#//apple_ref/doc/uid/1051i-CH6-SW11 -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Core Data Disable Undo
[[managedObjectContext undoManager] disableUndoRegistration]; -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Core-Data : how to merge two contexts ?
I'll probably end up using the merge... method available but that makes me feel bad to save a document automatically when the user should be the only one responsible for this. For example, the user will not be able to use the Revert command from the File menu to restore his document to its original state like it is supposed to work (or I'll probably have to subclass the standard behavior by saving a copy of the sqlite file in the temp area just in case the user needs to revert). Eric.___ I'm not a Core Data expert by any stretch of the imagination, but NSPersistentDocument does support revert and other such features, so it's clearly possible. The NSPersistentDocumentation Class Referencehttp://developer.apple.com/mac/library/documentation/cocoa/Reference/ApplicationKit/Classes/NSPersistentDocument_Class/Reference/Reference.html indicates that the save operation simply adds a new persistent store (if it is not already saved) to the managed object context and then invokes save:. This suggests a possible solution: When the user opens your application, use an in-memory persistent store. If they're opening an existing document, use the migrate... method on NSPersistentStoreCoordinator to migrate the on-disk store to an in-memory one. Once you've loaded everything into memory, you can invoke save on multiple MOCs as much as you like without it being written to disk, since the on-disk store is no longer attached. When you actually want to save to disk, simply add an on-disk persistent store to the MOC. You'd probably just delete the old on-disk one and then add a new persistent store at the same URL. I assume you'd have to call save on your MOC after doing so. You could then immediately remove the on-disk store and continue on with in-memory store. Alternatively, you could migrate to an on-disk store and then back to an in-memory store, but I suspect that would be less efficient. I've tried precisely none of the above personally. I'm just throwing ideas out there. If the above isn't a feasible way to do this in Core Data, I'd love to know why. -BJ Homer ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Problem with allocating memory
NSLog(@%d, myString); Change this line to: NSLog(@%p, myString); that will print the value of the pointer, which you'll see changing. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
GC and atomic getters/setters
In the Garbage Collection Programming Guide: Architecture [1], an example is given of a set of non-GC getters and setters which use @synchronized(self) to control the access to the ivar, and in the setter to protect the releasing of the old object and retaining of the new. Then, a GC example is given in which the getters and setters have no synchronization; the getter simply returns the value, and the setter simply assigns the new value. I understand why the setter is so much simpler under GC; no retain/release fiddling is necessary. However, I'm confused about the lack of synchronization in the GC examples. I know there's lots of skepticism as to whether synchronization at the getter/setter level is even useful (hence the general recommendation to make properties nonatomic). But assuming that you wanted it there in the first place, why does the GC version not need the synchronization? Is it simply because the setter is doing less, and thus the getter wouldn't ever catch the setter halfway through its setting? (After releaseing the old value, but before retaining the new, for example.) -BJ [1] http://developer.apple.com/mac/library/documentation/Cocoa/Conceptual/GarbageCollection/Articles/gcArchitecture.html#//apple_ref/doc/uid/TP40002451 ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: NSWorkspaceDidMountNotification not firing on Snow Leopard
On Thu, Oct 8, 2009 at 2:39 AM, Dave Keck davek...@gmail.com wrote: Not sure why it's not working, but if it turns out to be a bug with NSWorkspace, you might try using the Disk Arbitration framework instead. See DARegisterDiskAppearedCallback(). Note that there's a difference between disk appeared and disk mounted. Specifically, at the time of the DiskAppeared callback, the drive is NOT mounted. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Constructive Criticism
On Wed, Oct 7, 2009 at 10:53 AM, Derek Chesterfield d...@mac.com wrote: On 6 Oct 2009, at 22:48, Alastair Houghton alast...@alastairs-place.net wrote: Oh, and since I'm in the dot-syntax-is-evil camp, s/self.year/[self year]/g in Bill's code :-D :-D Just an aside, but does either syntax got optimised by the compiler (GCC or LLVM). Obviously it can't in all cases, but this seems an obvious case where it could be replaced by an assignment.___ If you replace self.something = @value with something = @value, Key-Value Observing won't work. So no. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Correct way to tell if a path is to a .bundle?
Rick, You could also use: NSBundle pluginBundle = [NSBundle bundleWithPath: fullPath]; This will return an NSBundle object as your require or nil if fullPath does not identify an accessible bundle directory. So... if ( pluginBundle == nil ) ... then it is not a valid bundle. This isn't actually true. For example, you can create a bundle with the path to a flat executable, and if that executable happens to have an Info.plist embedded inside it, you can access the values in the plist as if it were a full bundle. Likewise, if you point it at a random folder, you may still get a valid object back. I've got some rubycocoa scripts that take advantage of that very fact. Sorry. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Stability on Snow Leopard
On Wed, Sep 23, 2009 at 6:24 AM, Kirk Kerekes kirkkere...@gmail.com wrote: ... If you don't happen to be using any of these, (or any macros that hide relevant code, because the analyzer appears to operate only on unexpanded code) you should be golden. The analyzer definitely expands macros. I've got some legacy code at work that's got a frequently-used macro that can basically return from the method at any point, and it's producing ALL sorts of memory leak warnings. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Creator Codes in Snow Leopard
On Wed, Sep 23, 2009 at 10:32 AM, Todd Heberlein todd_heberl...@mac.comwrote: Some may find the following Apple Insider article on the the topic useful: Inside Snow Leopard's UTI: Apple fixes the Creator Code http://www.appleinsider.com/articles/09/09/22/inside_snow_leopards_uti_apple_fixes_the_creator_code.html Some may also find it misleading, since it implies that the UTI can be set on a per-file basis, independent of type code and extension. This is false. As a result, most of their conclusions are incorrect as well. If you can't set the UTI differently on two files with the same type code and extension, it can't serve as a creator code. Incidentally, this is not a complaint against UTIs; they are very useful. They're just not meant to solve the creator code problem. -BJ Homer ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: an app that never quits
On Sat, Sep 19, 2009 at 1:07 AM, Erick Calder e...@arix.com wrote: I want to write a daemon for the iPhone. my goal is to record the orientation of the phone across time for later analysis. I am unsure how this could be done since it seems only one application gets to run at a time i.e. when the user takes a call my program quits. can this be done? Not without jailbreaking; you simply can't write background apps on the iPhone. I'm not sure if you could do it on a jailbroken phone, since I've never played with one. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: #pragma to suppress a warning message
If you're just wanting to use the method and avoid the warning, add a category to NSLocale declaring the preferred languages. Just add the interface; no implementation is necessary. You may want to do further investigation; however. It's possible that the preferredLanguages method appeared mid-way through the 10.4 lifecycle, so it may work for some Tiger users and not others. -BJ On Wed, Sep 16, 2009 at 7:09 PM, Jay Boyer j...@automaticduck.com wrote: I have three related questions. I’d like to suppress a particular warning message in the source file. In gnu it could be done as follows: #pragma Warnings(Off) NSArray *languages = [NSLocale preferredLanguages]; #pragma Warnings(On) Is there a way to do this in xcode with #pragma? Also, can anyone point me to a list of the #pragma’s for xcode? Finally, I am doing this because the preferredLanguages method is specified to be an OS 10.5+ method and the project I am working on is being built on the 10.4 SDK. Nonetheless, on the 10.4 machine where I tested this, the method works. Does anybody know what the story is with this method and 10.4? Is this method actually supported by 10.4 or is it something that happens to be supported if certain other software has been installed on a 10.4 platform? Thanks, Jay___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Retaining a NSURL and retaining its -path
On Sat, Sep 12, 2009 at 10:43 AM, John Love jote...@charter.net wrote: In my controller, one of my instance variables is a NSURL and I retain it because I pass it to a 2nd controller. In my second controller, I extract [myURL path] and look at it in a secondary thread loop and everything works fine. I began to think if I could eliminate that call to [myURL path] every time through that loop I would save some time. My first attempt was to pass that NSURL in the same manner and then place the extracted [myURL path] into an instance variable of the 2nd controller. Okay so far .. and then I assumed that if myURL was retained in the 1st controller, then naturally its NSString -path was also retained .. but it crashed with release message sent to a already released object (or something like that). Only when I extracted the -path *and* retained it before I stored it as an instance variable of the 2nd controller did it work. Basic question: if a parent object is retained, why isn't each sibling component object of that parent retained?? It's very possible that the NSURL doesn't actually keep an instance variable for the path, and instead simply generates it on demand. It would probably return it to you autoreleased and then forget all about it, so if you didn't retain it, you'd be in trouble. In short, if you care about an object obtained through a non-owning method, retain it. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Cleaning garbage in Core Data
On Sun, Aug 16, 2009 at 10:35 AM, Squ Aire squ...@live.com wrote: I am not *explicitly* marking anything as garbage. Whenever a user decides to remove a ValidKeys managed object, corresponding key-value pairs in all the userInfo dictionaries are *conceptually* marked as garbage. This is because I do not want to show the beach ball to the user while things are getting cleaned up. I want to postpone the cleaning up until later when it will not bother the user. If the goal is to avoid beachballing the user, you may be able to simply put the cleanup logic into a background thread and fire it off immediately. Beachballs only happen when the main thread is blocked. Now, if this is data that is displayed and manipulated in the UI, you may need to do some synchronization to avoid race conditions. But in general, avoiding beachballs is a matter of doing things in the background instead of delaying it until later; if you wait to clean up garbage, you'll just postpone your beachball until later. Now, there may still be merit to batching the deletions; you could make a background thread that runs cleanup every 1.0 seconds on any object in a deletion queue or something. I'm not a Core Data expert (yet), but you will need to give the background thread a separate NSManagedObjectContext. As you mentioned, you'll need to notify the main thread's MOC of the changes. Luckily, in 10.5 there's -[NSManagedObjectContext mergeChangesFromContextDidSaveNotification:]http://developer.apple.com/documentation/Cocoa/Reference/CoreDataFramework/Classes/NSManagedObjectContext_Class/NSManagedObjectContext.html#//apple_ref/doc/uid/TP30001182-SW9, which takes care of that. Register an observer on the NSManagedObjectContextDidSaveNotification notification with the background MOC as the object and the main MOC as the target, and whenever the background thread performs a save, the main thread's MOC will be updated. That's how I'd do it, anyway. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Custom NSArrayController - Dynamic Class?
On Jul 18, 2009, at 11:52 PM, BJ Homer bjho...@gmail.com wrote:
On Sat, Jul 18, 2009 at 4:23 PM, Quincey Morris quinceymor...@earthlink.net
wrote:
On Jul 18, 2009, at 15:07, Kyle Sluder wrote:
I would instead recommend using -setValue:forKey: like this:
[object setValue:[NSNumber numberWithInteger:[[self arrangedObjects]
indexOfObject:object]] forKey:@index]
Yes, it's more sensible.
But now that I think about it, the performSelector approach has
one *slight* advantage to the developer. If you ever use Xcode's
refactoring to change the name of the property, it will miss the
property name in the string. With @selector, the method name still
doesn't change, but the refactor window does give a warning that
it's not going to change automatically.
Perhaps the best option is option (c): create a IndexedObject
abstract superclass (if there isn't one already) and use
'object.index = ...' after all.
In order to preserve the contract of NSArrayController (which is
that you can add any object with addObject:), I'd recommend doing
something like this:
- (void)addObject:(id)object {
if ([object respondsToSelector:@selector(setIndex:)] {
object.index = [NSNumber numberWithInt:[[self arrangedObjects]
indexOfObject:object]];
}
[super addObject:object];
}
Note that I call super's addObject: at the end. I have no idea what
the implementation of NSArrayController's addObject: is, but it's
always better to have things set up before you pass something along
to super. Imagine, for example, that NSArrayController writes the
object immediately to disk when added. Since you haven't set your
index yet, it would be incorrect. (I don't think it actually writes
anything to disk at that point, but you get the idea.)
-BJ
Actually, use [object setIndex:] instead, and cast it as an
IndexedObject*. That will get rid of your compiler warnings.
-BJ
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Re: Custom NSArrayController - Dynamic Class?
On Jul 19, 2009, at 11:21 AM, Kyle Sluder kyle.slu...@gmail.com wrote: On Jul 18, 2009, at 11:52 PM, BJ Homer bjho...@gmail.com wrote: Actually, use [object setIndex:] instead, and cast it as an IndexedObject*. That will get rid of your compiler warnings. -BJ We're talking about the case in which you don't have a managed object subclass, and therefore there is nothing to cast to. --Kyle Sluder Oh, right. Cast it to (id) then. Though if it's already passed in as an id, that's obviously unnecessary. Point is, calling setIndex: instead of object.index= will let it compile w/o warnings, in certain situations. Thanks for the correction. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Where to release in UIView
That actually is a valid concern; since you're on the iPhone, memory constraints are tight, and your view may actually be unloaded at some point. Instead of doing additional initialization in awakeFromNib, (which has no counterpart), I'd recommend doing your additional setup in viewDidLoad: on the associated UIViewController. Then, in viewDidUnload: you can release anything you instantiated in viewDidLoad:. Note that viewDidUnload is only available in iPhone OS 3.0 and later. -BJ On Sat, Jul 18, 2009 at 1:56 PM, DKJ hatzicw...@shaw.ca wrote: Thanks to all who replied. I was concerned whether the object might somehow get re-instantiated from the nib without dealloc being called first. If I understand memory management correctly, that would produce a leak. I'm assuming that the object wouldn't be re-instantiated without its previous instantiation being released. But I'd sleep better having an expert opinion. dkj On 18-Jul-09, at 7:59 , DKJ wrote: I've got a UIView object that uses an NSDictionary. The UIView is instantiated from a nib, so I initialise the dictionary in awakeFromNib, since the initWithFrame: method is never called. Is it appropriate to release this dictionary in the UIView dealloc method? dkj ___ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Custom NSArrayController - Dynamic Class?
On Sat, Jul 18, 2009 at 4:23 PM, Quincey Morris quinceymor...@earthlink.net
wrote:
On Jul 18, 2009, at 15:07, Kyle Sluder wrote:
I would instead recommend using -setValue:forKey: like this:
[object setValue:[NSNumber numberWithInteger:[[self arrangedObjects]
indexOfObject:object]] forKey:@index]
Yes, it's more sensible.
But now that I think about it, the performSelector approach has one
*slight* advantage to the developer. If you ever use Xcode's refactoring to
change the name of the property, it will miss the property name in the
string. With @selector, the method name still doesn't change, but the
refactor window does give a warning that it's not going to change
automatically.
Perhaps the best option is option (c): create a IndexedObject abstract
superclass (if there isn't one already) and use 'object.index = ...' after
all.
In order to preserve the contract of NSArrayController (which is that you
can add *any* object with addObject:), I'd recommend doing something like
this:
- (void)addObject:(id)object {
if ([object respondsToSelector:@selector(setIndex:)] {
object.index = [NSNumber numberWithInt:[[self arrangedObjects]
indexOfObject:object]];
}
[super addObject:object];
}
Note that I call super's addObject: at the end. I have no idea what the
implementation of NSArrayController's addObject: is, but it's always better
to have things set up before you pass something along to super. Imagine,
for example, that NSArrayController writes the object immediately to disk
when added. Since you haven't set your index yet, it would be incorrect.
(I don't think it actually writes anything to disk at that point, but you
get the idea.)
-BJ
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Re: Core Data debugging
NSError *err; BOOL result = [moc save: err]; Make sure you initialize err: NSError *err = nil; Otherwise, you may be dealing with a bogus error object, since method-scope variables are not automatically initialized to 0. (Instance variables are initialized, btw.) I don't think that would affect the return value of save, but it's a good habit either way. -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: iTunes COM interface for Windows; need the equivalent for iTunes on the Mac
Or, if you want something more code-y, try the Scripting Bridge: http://developer.apple.com/documentation/Cocoa/Conceptual/ScriptingBridgeConcepts/UsingScriptingBridge/UsingScriptingBridge.html#//apple_ref/doc/uid/TP40006104-CH4-DontLinkElementID_11 -BJ On Thu, Jul 16, 2009 at 3:55 PM, Nick Zitzmann n...@chronosnet.com wrote: On Jul 16, 2009, at 3:42 PM, Michael A. Crawford wrote: So, is there an SDK for accessing iTunes on the Mac? AppleScript? Nick Zitzmann http://www.chronosnet.com/ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: ibtool and genstrings do nothing
genstrings does not produce output. It does, however, produce Appdel.strings. -BJ On Thu, Jul 16, 2009 at 3:51 PM, Development developm...@fornextsoft.comwrote: I am trying to use genstrings: genstrings AppDelegate.m Appdel.strings from the terminal window and I get no errors and no output. Likewise when I do ibtoo -generate-strings-file MainWindow.nib MainWindow.xib I get no error and no output. I am in the terminal in the correct directory so I have no idea what I'm doing wrong ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: {Cocoa semi-related} Unable to de-archive an archive from SQLite.
It's not an archive; that's the actual binary executable. Just rename it to something more reasonable. I dealt with this just last week. -BJ On Tue, Jul 14, 2009 at 5:06 PM, Frederick C. Lee amourinet...@gmail.comwrote: I'm trying to dearcive sqlite3-3.6.16-osx-x86.bin. But what I get is: sqlite3-3.6.16-osx-x86.bin.cpgz Is there a remedy? Ric. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: literal strings - who do they belong to?
But then I saw the case where I have an object which returns, as a method
result or a property, one of its instance variables. The caller holds on to
it (without retaining it) then releases (and deallocs) my object. My object
releases its instance variables which results in the caller holding a
reference to a dead value.
{
Object *o = [Object new];
NSString *s = o.somevalue;// gets o's instance variable
(without retain)
[o release]; // o's instance variable is released
NSLog(@Crash: %@,s) // accesses dead string
}
So, yes, the retain/autorelease isn't superfluous at all, though the usage
pattern that would trigger the problem seems relatively unlikely (in my
example, o seems far more likely to be autorelease'd). Is there a more
common case that I'm missing?
If o were in an NSDictionary that was passed to you in a parameter, for
example, and you removed the key from the dictionary, you'd trigger the same
problem.
-BJ
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Re: Why do I receive KVO notification when new value IS the old value?
Likewise, what if I had a program that was counting the number of X events per 10 seconds, and I wanted to add a data point to a list every time it was updated? I would definitely want to record the same number twice in a row. It may not be a common case, but reporting the value enables situations that filtering it out would not allow. Besides, it's not a waste of CPU cycles; if the framework did the equality check for you first, it would be performed on *every* notification. This way, you can only perform it on the notifications where you need it. -BJ On Wed, Jul 8, 2009 at 4:17 PM, Greg Guerin glgue...@amug.org wrote: Jerry Krinock wrote: This happens not only when the new and old values are -isEqual:, but when they are identically the same pointer. I can't think of any reason why anyone would want notification of a no-op. What if the operation isn't a no-op? What if the operation represented some kind of accumulation instead of replacement, or an incremental change instead of assignment? -- GG ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: AsyncSocket. Troubles with MTMessageBroker didReceiveData
Neither AsyncSocket nor MTMessageBroker are part of Cocoa, and thus you're very unlikely to find help on a Cocoa developer's list. They're both third-party classes. My best recommendation is that you try Google. The first result for searching *AsyncSocket MTMessageBroker* is thishttp://www.macresearch.org/cocoa-scientists-part-xxix-message, which seems to have an example that may help you. One other thought: if your delegate methods aren't being called, have you actually called [socket setDelegate:self]? -BJ On Tue, Jul 7, 2009 at 2:24 AM, Carlo Gulliani carlogulli...@yahoo.comwrote: Nobody knows? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/bjhomer%40gmail.com This email sent to bjho...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: MDSchemaCopyAllAttributes() returning nil
In this particular instance, don't forget that Spotlight importers can live in ~/Library/Spotlight as well as within app bundles in ~/Applications. Any answer that MDSchemaCopyAllAttributes() would give you when running as root might be incorrect for the user who's actually the results. --Kyle Sluder Interesting. So what you're saying is that the schema is actually defined on a per-user basis, depending on what applications and spotlight importers are installed for that user? Shouldn't root, though, still be able to list the schema provided by apps in /Applications and importers in /Library/Spotlight Importers? -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Binding to an NSArrayController subclass
I have an NSTableView displaying a collection of rules. (Let's imagine
they're smart playlists, a la iTunes.) I set up an NSArrayController to
provide access to these playlists, and at that level, everything works. The
ArrayController has its contentSet as the set of playlists, and I can
display the name of each playlist by binding the Value of an NSTableColumn
to {bindTo = PlaylistArrayController, controllerKey = 'arrangedObjects',
modelKey = 'name'} in Interface Builder. (Forgive the odd notation, I'm
just trying to provide enough information.) With this configuration, the
tableview displays the name of each playlist correctly.
However, I also wanted to display the number of songs matching each
playlist. This is something the playlist won't know when it's created,
since files matching the rule might be added later. Hence, I can't bind
directly to a value on the Playlist object. Instead, I created a subclass
of NSArrayController called PlaylistArrayController, which has a reference
(connected through IBOutlets in interface builder) that can provide it
information about what files match the playlist. I changed the class of the
array controller in InterfaceBuilder, so that it's actually of class
PlaylistArrayController. Retrieving the name still works at this point.
I then attempted to add another key to the controller, parallel to
arrangedObjects. Where arrangedObjects returns an array of Playlists,
arrangedCounts should return an array of NSNumbers. This is the
implementation:
- (id)arrangedCounts {
NSArray *objects = [self arrangedObjects];
NSMutableArray *counts = [NSMutableArray arrayWithCapacity:[objects
count]];
Playlist *rule;
NSEnumerator *ruleEnumerator = [objects objectEnumerator];
while (rule = [ruleEnumerator nextObject]) {
int count = [playlistController countForRule:rule];
[counts addObject:[NSNumber numberWithInt:count]];
}
return counts;
}
However, when I attempt to bind another column to {bindTo =
PlaylistArrayController, controllerKey = 'arrangedCounts', modelKey =
blank}, I get problems. I have walked through the arrangedCounts method and
verified that it is, in fact, returning an array of NSNumbers just as I
expect. However, instead of displaying a number with each name, each row in
the table tries to display the entire array of counts. If I tweak
arrangedCounts to always return the string @hi, then each row will display
hi in that column.
The only difference I can see between the two is that I am not using the
modelKey of the property, since I actually want to display the value of each
object (an NSNumber) itself. I've even tried adding an NSDictionary to my
counts array with the NSNumber as the value for the key count, and setting
modelKey = 'count' on the bindings, but that still didn't work. Is there
some deep magic behind [NSArrayController arrangedObjects] that I don't have
access to? Is there a better way to solve my problem? I considered using
an NSValueTransformer, but I would have to create a static
playlistController object which would be shared app-wide, and I'd rather not
do that.
Please let me know if I'm missing some important piece of information here.
-BJ Homer
bjho...@gmail.com
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Re: A tree data structure?
On Wed, May 6, 2009 at 2:15 AM, Andreas Grosam agro...@onlinehome.dewrote:
On May 5, 2009, at 6:54 PM, Clark Cox wrote:
On Tue, May 5, 2009 at 8:28 AM, Andreas Grosam agro...@onlinehome.de
wrote:
On May 5, 2009, at 3:21 PM, Ken Thomases wrote:
Since you mention NSTreeController and CFTree, you may already be aware
of
this, but just in case you aren't: have you looked at NSTreeNode?
I didn't - thanks for this hint :) And it looks perfect if I decide to
implement my own container, but I'm going to search some more
opportunities.
Beyond NSTreeNode, what more do you have to implement? (i.e. there
needn't be any container for a tree data structure, it can be
composed completely of its nodes).
Well, this depends on your requirements and whether it is a search tree or
a graph.
In my actual case I wont need much functionality.
Some possible requirements may be:
copy, slice, count, rotate, enumerators with the five most common traversal
methods, partial locks, thread safety,
time and space complexity constraints, etc.
Instantiate a root node, and that can be your container, then add
and remove children as appropriate.
In may case, this will work since, as mentioned, I just need a graph,
insert methods and a traversal algorithm.
Regards
Andreas
Quinn Taylor, who made the CHDataStructures framework I referenced earlier,
asked me to post the following in response to this latest post.
These links should be helpful...
-
http://dysart.cs.byu.edu/websvn/filedetails.php?path=/CHDataStructures/source/CHAbstractBinarySearchTree.m
-
http://dysart.cs.byu.edu/websvn/filedetails.php?path=/CHDataStructures/source/CHAbstractBinarySearchTree_Internal.h
Searching for - (id) nextObject { at the first link puts you right at the
traversal algorithms he's talking about.
Not sure what he's talking about with slice and rotate, but variants of this
code would make implementing the operations he talks about a lot easier for
an N-ary tree, although not trivial. :-)
Thanks,
- Quinn
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Re: A tree data structure?
You may be interested the CHDataStructures framework, hosted by the BYU
CocoaHeads group. It has a number of such structures that should work for
you.
http://cocoaheads.byu.edu/code/CHDataStructures
http://cocoaheads.byu.edu/code/CHDataStructures-BJ Homer
On Tue, May 5, 2009 at 7:10 AM, Andreas Grosam agro...@onlinehome.dewrote:
NSTreeController and CFTree is not exactly what I'm searching for. I would
like to have a *pure*, simple and effective but complete tree data
structure which comprises a hierarchy of objects:
root
|- object1
|- object2
|- object4
|- object5
The container shall be sequential, that is its elements shall be ordered.
A possible approach could look like this:
@interface Tree {
Node* root;
}
-(void) addObject: (NSObject)* data into:(Node*)parent;
-(TreeEnumerator*) enumeratorOfType:(int) enumeratorType;
- (int) count;
...
@end
Class Node contains the data and structural information:
@interface Node {
NSMutableArray* data;
Node*parent;
}
-(void) addObject:(NSObject*) data;
-(int) count;
...
@end
Is there already something available like this?
Thanks in advance for hints.
Regards
Andreas Grosam
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Re: unrecognized selector sent to instance
On Wed, Apr 15, 2009 at 9:02 AM, Bill Bumgarner b...@mac.com wrote: On Apr 15, 2009, at 7:04 AM, Jason Stephenson wrote: So, the error that I get at runtime makes it appear that my SIGIOBzip2OutputStream does not respond to the -[initToFileAtPath:append:] selector, but it does. In the debugger, it looks as though SIGIOBzip2OutputStream's super class is the object that doesn't respond to that selector. But, it's superclass is NSOutputStream, and it is documented to respond to that selector and I get no warnings about the selector when compiling. Actually, it doesn't. A subclass of NSOutputStream responds to that method. NSStream/NSOutputStream are both abstract classes with very specific subclassing notes. See the documentation: http://developer.apple.com/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSOutputStream_Class/Reference/Reference.html Which says: Subclassing Notes The NSOutputStream is a concrete subclass of NSStream that lets you write data to a stream. Although NSOutputStream is probably sufficient for most situations requiring this capability, you can create a subclass of NSOutputStream if you want more specialized behavior (for example, you want to record statistics on the data in a stream). Seems to be concrete to me. Nevertheless, calling it on super does throw an exception; you might just try calling [super init] and see what happens. Note that you'll also get exceptions on [super open] and [super close] in those respective methods, since they're not defined on the superclass. Look at the subclassing notes on both NSStream and NSOutputStream, and you'll be closer. http://developer.apple.com/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSOutputStream_Class/Reference/Reference.html And: http://developer.apple.com/DOCUMENTATION/Cocoa/Reference/Foundation/Classes/NSStream_Class/Reference/Reference.html#//apple_ref/occ/cl/NSStream There is a very specific set of methods you need to override. -init isn't one of them; you don't need to call super's implementation, apparently. b.bum ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Dragging around an NSImageView
On Fri, Apr 3, 2009 at 9:54 AM, Randall Meadows cocoa-...@not-pc.comwrote: On Apr 3, 2009, at 4:14 AM, Aaron Scott wrote: I'm trying to figure out how to be able to drag an NSImageView around. The NSImageView has been added as a subview to another NSImageView. Basically, I'm trying to drag a grey box around over the top of a picture. I can programmatically move it around but I can't seem to find the right code to allow me to drag it around. You don't actually drag a *view*, you drag an image. Pedantic, perhaps, but important. When you start a drag, you specify the image that will be dragged. See NSView's -dragImage:at:offset:event:pasteboard:source:slideBack:, as well as Dragging Sources in the Drag and Drop Programming Topics for Cocoa reference. That's true if you're trying to do drag-and-drop programming, but I don't think the OP was trying to do that. I think he's basically trying to change the frame of a subview. If that's the case, I think you'll want to look at the documentation for -[NSResponder mouseDragged]. (Note that NSImageView is a type of NSResponder.) -BJ ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
-[UIView actionForLayer:forKey:] returns NSNull
I have a UIWebView displaying the contents of a local html file. When the user presses a button, I'd like to transition, with a fade, to another UIWebView (also displaying local content; no need to wait for the network.) The UIView transitions will not do a fade, but a CATransition on a CALayer would do the trick. Of course, I'd need to apply to the CATransition to a layer containing both of the webViews, but that's fine; the UIWebViews are both subviews of another UIView that serves simply to contain both of them. As I understand, when a subview is added to a view, the layer calls -[CALayer actionForKey:], which goes through the following search (self refers to the CALayer on which actionForKey: was called): 1. [self.delegate actionForLayer:forKey:] 2. [self.actions valueForKey:] 3. Recursively search self.style for an actions dictionary, then [actions valueForKey:] 4. [self defaultActionForKey:] If any of these steps returns a non-nil result, that value is used. Especially relevant in this case is the fact that when an NSNull is returned, the search stops and nil is returned from [CALayer actionForKey:]. The problem is that, as near as I can tell, UIView's implementation of actionForLayer:forKey: returns an NSNull. I would have liked to add a CATransition to the container view's layer's action dictionary (view.layer.actions) for the key kCAOnOrderIn. However, since UIView's actionForLayer:forKey: returns NSNull, the search always bails out after the first step. This seems odd, since it seems that defaultActionForKey: never actually gets the chance to return a default action unless you're already changing things. Am I missing something here, or is a UIView's layer's actions dictionary only usable if you're subclassing UIView? -BJ Homer ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
