At runtime, when listing the classes in my main bundle (using objc_getClassList). I see things like :
_TtGCs18ManagedProtoBufferVs29_HashedContainerStorageHeaderVs5UInt8_
_TtGCs13ManagedBufferVs29_HashedContainerStorageHeaderVs5UInt8_
_TtGCs28_NativeDictionaryStorageImplCSo8NSObjectPs9AnyObject__
_TtGCs18_HeapBufferStorageVs18_StringBufferIVarsVs6UInt16_
Any ideas what those are??
Also, they do not always appear...
I also see NSKVONotifying_NSUserDefaults sometimes.
Related
I have a fork of the JavaScriptCore framework, where I have added a function of my own, which is exported. The framework compiles just find. Running nm on the framework reveals that the function (JSContextCreateBacktrace_unsafe) is indeed exported:
Leo-Natans-Wix-MPB:JavaScriptCore.framework lnatan$ nm -gU JavaScriptCore.framework/JavaScriptCore | grep JSContextCreateBacktrace
00000000004cb860 T _JSContextCreateBacktrace
00000000004cba10 T _JSContextCreateBacktrace_unsafe
However, I am unable to obtain the pointer of that function using CFBundleGetFunctionPointerForName or dlsym; both return NULL. At first, I used dlopen to open my framework, then tried using CFBundleCreate and then CFBundleGetFunctionPointerForName but that also returns NULL.
What could cause this?
Update
Something fishy is going on. I renamed one of the JSC functions, and nm reflects this. However, dlsym is still able to find the function with the original name, rather than the renamed.
It's hard to track this down since it's highly dependent on your specific environment and circumstances, but it is very likely you're running into this issue because the system image has already been loaded and you haven't changed the name of the framework.
If you look at the source code for dlopen in dyld/dyldAPIS.cpp:1458, you'll notice the context passed to dyld is configured with matchByInstallName = true. This context is then passed to load which executes the various stages necessary for image loading. There are a few phases worth noting:
loadPhase2 in dyld/dyld.cpp:2896 extracts the ending of the framework path and searches for it in the search path
loadPhase5check in dyld/dyld:2712 iterates over all loaded images and determines if any of them have a matching install name, and if one does, it returns that instead of loading a new one.
loadPhase5load in dyld/dyld:2601 finally loads the image if it wasn't loaded/found by any earlier steps. (It's worth noting loadPhase5check is executed first, since image loading is a two pass process.)
Given all of the above, I'd try renaming your framework to something besides JavaScriptCore.framework. Depending on the install name of both the system framework and your framework, I'd also recommend changing the install name. (There are plenty of blog articles and StackOverflow posts that document how to do this using install_name_tool -id.)
I'm trying to keep my code as readable as it possible by keeping methods and files as short as I can and using nested classes for namespacing. It works fine except some really strange moment.
I have some class used for namespacing.
class Space { }
All classes used within that one are implemented in their own files as extensions.
extension Space {
class SomeClass {
// implementation
}
}
One of those SomeClasses have a number of quite sophisticated initialisers, so I have split them up to their own files as well and implemented it as follows:
extension Space.SomeClass {
convenience init(fromSomeSource source: SourceClass) {
self.init()
// other implementation
}
}
The problem is that some of those files works just fine, but some of them throwing 'SomeClass' is not a member type of 'Space' and I don't know why.
All of them are pretty similar. The only difference is implementation of an initialiser itself. All files are held in the same place and I have no idea why some of them works fine and some not.
I tried to move code from not working files into files that works fine and that works – Xcode agrees to see the code and said nothing against it. But when the very same code lies in its own file – Xcode or compiler doesn't want to understand that SomeClass is really a member of Space.
I tried to clean the build, including manual dumping of ~/Library/Developer/Xcode/DerivedData folder. Nothing helps.
Surely I can put it all in a single file and it will work fine, but what the reason why it so picky in my case?
I've tried to create a new file and move there all contents from one of the bad ones. It works, but only with certain file names. Some names gives the same error again, but it seems that if name is totally new and not similar to any of the existing ones - it works. Magic?
I've encountered similar issue, it seems like the complier is trying to process the file where you extend the nested class before the one where it's defined. Therefore you have this error saying that that Space has no member SomeClass.
The solution I've found is to go to your target settings, open Build Phases.
There, in Compile Sources section you should put the file where you define the nested class above files where you extend it.
This solution seems to even play well with your observation that when you recreate the file it sometimes compiles, because when you recreate the file its position in Compile Sources changes.
Something strange is going on with my Xcode 5. All of a sudden I'm getting Undeclared Identifier errors for all the values in my Constants.h file, which is imported in my Prefix.pch file.
Two things are weird here:
This hasn't happened before.
When I do build and run, the build succeeds and the app runs with no problems.
I tried restarting Xcode and the simulator, and even restarting the whole machine. No luck.
What's going on? How can I get rid of these false errors?
EDIT following rmaddy's request. The error is Use of undeclared identifier kOffsetFromTop (for example, there are other similar errors with different constants.)
I don't really want to post my entire constants file, but the constant in question is defined like this:
static int const kOffsetFromTop = 20;
When this happens I normally do the following
Comment out the import from the .pch
Clean all ⌘⌥⇧K
Delete derived data
Build
Then uncomment the import from the .pch and build again. I'm not sure which step is actually sorting the issue but this normally gets me going again.
Multiple points here :
You have a warning, not an error. A warning is just that, it warns you but does not prevent the code to compile. That is just to warning you that something is odd or unexpected, or to tell you that what you wrote may not be actually what you were intended, because the compiler finds it odd or not standard.
You didn't have the warning before probably because it wasn't activated by default in previous versions of Xcode. The latest version of Xcode5 activates more warnings (which is a good thing, as it warns you about more things that could go wrong in your code and encourage you to fix them), hence this new one you have but didn't have before.
As I understand what you describe, tour usage of a constant is incorrect (and that's probably why Xcode emits a warning).
The correct way to declare a constant that you want to be accessible from multiple files is to:
Declare it (define its existence and type) in a header (or in your pch) like this: extern <type> const <name>;
And define it (give it a value) only in one implementation file (like your main.m, your AppDelegate.m, some Constants.m file, whatever) like this: <type> const <name> = <value>
Some details and reminders about constants declaration (also valid in standard C)
You use static <type> const <name> = <value>; in an implementation file only, when the constant is local to the file and does not need to be used by other files. In that case, you declare it typically in the .m file in which you will use it, and other files won't have access to it (which is quite what the static keyword means, actually (making the constant attached/local to the file).
In that matter, you should never declare a constant that way in a header file (and especially not in your .pch file), because header (and pre-compiled header) files will be included multiple times. If you do that, this would declare as many independent constants as the number of implementation files you include your headers into (this has evil side effects especially for pointers/objects, for exemple declaring an NSString* const that way -- for, say, using it as a notification name of error domain -- will create multiple string constants, with the same value but different addresses, which will probably not behave like you will expect)
When you need to declare a constant that you need to use / be accessible from multiple implementation files, so declaring this constant in a header file so that it is known to all implementation fiels that includes this header, you need to only declare it in the header, and not making it static (at this would run against the purpose of having the same constant for all files instead of multiple independent instances of the constant) but instead indicate extern to let the compiler know that its definition (value) is set elsewhere. Hence the solution given above.
I am running into a bizarre situation where a unit test's execution is behaving differently than the normal execution of a piece of code.
In particular, I am using a library called JSONModel, and when I am attempting to deserialize an object from a JSON string, one line in particular is causing problems when I step through the executing test case:
if ( [[property.type class] isSubclassOfClass:[JSONModel class]] ) ...
If I put a breakpoint before (or after) this line and execute:
expr [[property.type class] isSubclassOfClass:[JSONModel class]]
...in the debugger, it prints \x01 as the value (i.e. true), however when I actually step the instruction pointer, it behaves as though it is false, going instead into the else block. Again, typing the expression into the debugger again shows it as true even still.
I'm curious if anyone has seen similar behavior before and has any suggestions as to what could possibly be going wrong. I'm quite certain I'm not including different definitions for anything, unless Xcode has different internal cocoa class implementations for testing.
Update: Here's some even weirder evidence: I've added some NSLog statements to get an idea for how the execution is seeing things. If I log property.type.superclass I get JSONModel back (as expected); however if I log property.type.superclass == [JSONModel class] I get false!
To me this is indicating that the JSONModel the unit test execution is seeing is somehow a different JSONModel class that I'm seeing at runtime (and what it should be seeing). However, how that is happening I can't figure out.
Could this be caused by a forward class declaration or something like that?
Well I seem to have discovered a "solution" by experimentation. It turns out if I replace [JSONModel class] with NSClassFromString(#"JSONModel") it works swimmingly!
Now why this is I cannot say, and will give the answer to whoever can explain it!
I had the exact same problem, here's what was happening.
As expected with this kind of behaviour, it was an issue with the class being duplicated. As with you, [instance class] and NSClassFromString would return different values. However, the class were identical in all points : same ivar, same methods (checked with the obj runtime). No warning was displayed at compile, link and/or runtime
In my case, the tests were about a static library used in my main application (Bar.app).
Basically, I had 3 targets:
libFoo
libFooTests
Bar.app
The tests were performing on the device, and not on simulator. As such, they needed to be logic tests, and not unit tests, and had to be loaded into an application. The bundle loader was my main app, Bar.app.
Only additional linker flag was -ObjC
Now, Bar.app was linking libFoo.
It turns out, libFooTests was also linking libFoo.
When injecting libFooTests in the test host (Bar.app), symbols were duplicated, but no warning were presented to me. This is how this particular class got duplicated.
Simply removing libFoo from the list of libraries to link against in libFooTests did the trick.
near the top of the code i see things like,
btn_dropdown._visible = false;
mcMenuBkg._visible = false;
but I can't find these assets anywhere in the library or in any code, how does this make any sense?
The movie clips in the library that look the same have different names and I can delete them entirely and they still show up when I compile and run, or I can add trace statements into their code and they never get called.
where on earth are these assets defined?
In theory, any clip you see at runtime could be dynamically created, by making an empty MC and drawing in whatever contents you like with the drawing API. However, if you see clips in the library that are similar to what's showing up at runtime, then it's very unlikely that that's happening.
Your first step should probably be another look through the library. Remember that instance names don't have to be the same as MC names; even if something is called "Menu Holder" in the library there might be an instance of it somewhere called "mcMenuBkg" or whatever. But the fact that you can delete stuff without changing the output is mysterious.
So, other possibilities: contents are being loaded externally, or imported via runtime sharing. If feasible, try moving your SWF to a temp directory and running it from there; that should break all loads (unless contents are loaded from a remote URL).
Or, you're looking at the wrong clips in the library. If it's a crufty project there may be unused stuff in there. Try expanding the library wide enough to see the "Use count" column, and select "update use counts" from the library menu. Anything with a count of 1 or higher is part of your FLA's stage content - either it's sitting on the main stage or it's a child of something that is. Clips with a use count of 0 may still be used if they have a linkage ID; they could be created at runtime with attachMovie(). However, for any clip with a use count of 0 and no linkage id, it's safe to assume that it's unused, and irrelevant to what happens at runtime.
If none of that helps, the only things that come to mind are sanity checks... open up everything on the stage and every clip with a linkage id, and check for empty/invisible MCs. Check the Movie's export settings to make absolutely sure the SWF you're checking is the same one being published. And just for grins, open up the "Scenes" panel and make sure that some diabolical fiend hasn't put important content on a separate scene where no sane man would look for it.
Vague answer for a vague question. :D Hope it helps...
You can create movie clips with code dynamically.
This means that you may not have them in your assets if you are unable to find them.
You can create any type of symbol using a constructor out of thin air with actionscript alone.
I would search the code for one of these
var mybutton:SimpleButton=new SimpleButton();
If they're being set to
_visible = false
you won't see them anyway - and as ActionScript 1/2 doesn't do runtime error reporting, the Flash player won't complain if they're not actually there on the stage. If they're not being used, just delete them.