Is there a built-in function to make an NSMethodInvocation from 'the current
method I'm in with all current parameters', or does anyone have any code
they've written to do this?
Motivation, I'm writing a display class which can get updated from a background
thread, it has a whole load of methods, some of which don't lend themselves to
performSelectorOnMainThread (some take more than two arguments, some take
primitives and I don't really want to wrap and unwrap into NSNumbers all over
the place). What I really would like is in each method to be able to write
something like
if( ![ NSThread isMainThread ] )
[ NSMagicFunctionReturningAnInvocationForThisCurrentFunction()
performSelectorOnMainThread:@selector( invoke ) withObject:nil waitUntilDone:NO
];
else
{
// method performing code here
}
but there is of course no such function I'm aware of nor can I easily think how
I'd write such a thing.
I have a current solution for those methods which are properties using
forwarding because forwardInvocation: is the only function I know of which
gives me a pre-packaged invocation object but I find it a bit inelegant and it
only works for properties. That method briefly works as follows, if I want a
property 'foo', I declare it, then use @dynamic to suppress the compiler
warnings. In the class continuation I declare the same property prepended with
an given prefix (I'm using TS_ for threadsafe) and implement it. I then
override forwardInvocation: and methodSignatureForSelector: to check for the
existance of a method TS_<called selector> and if it exists I switch the
selector in the NSInvocation forwardInvocation: gives me and invoke it if I'm
on the main thread or forward it to the main thread if I'm not.
eg setFoo:123 is not implemented so methodSignatureForSelector: is called for
setFoo: and I return the signature for TS_setFoo:. Then forwardInvocation: is
called with a prepacked NSInvocation, I switch the selector to that for
TS_setFoo: and invoke it.
This only works for properties because I can only use @dynamic to suppress the
warnings on those, other declared methods in the interface need to be
implemented (or is there a way to suppress that warning) and the whole TS_
prefix thing seems a bit hokey to me so I was looking for a more direct way to
make an NSInvocation. _______________________________________________
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