I have been spending the weekend disecting code from WSMakeStubs and
getting into the depths of the WebServices framework, and I'm having
some trouble understanding a section of code.
When you use WSMakeStubs, it generates a pretty standard template
object (WSGeneratedObj) which has within it a getResultsDictionary
method. Prior to it's getting to this method, it's established the
WSMethodInvocationRef with an asynchronous callback. So far, I'm all
with this plan of attack. Then we get into this method:
The method in question:
- (NSDictionary*) getResultDictionary
{
if (fResult == NULL) {
if (fAsyncTarget != NULL) {
fAsyncTarget = NULL;
fAsyncSelector = NULL;
}
if (fResult == NULL) {
WSMethodInvocationRef invocation = [self getRef];
CFStringRef wsGeneratedMode = CFSTR("NS-WSSYNC");
WSMethodInvocationScheduleWithRunLoop(invocation,
CFRunLoopGetCurrent(), wsGeneratedMode);
while (fResult == NULL)
CFRunLoopRunInMode(wsGeneratedMode, -1.0, true);
WSMethodInvocationUnscheduleFromRunLoop(invocation,
CFRunLoopGetCurrent(), wsGeneratedMode);
}
if (fResult == NULL) {
[self handleError:@"WSMethodInvocationInvoke failed in
getResultDictionary" errorString:NULL
errorDomain:kCFStreamErrorDomainMacOSStatus errorNumber:paramErr];
}
}
return fResult;
}
What I don't understand is the call to CFRunLoopRunInMode. The
documentation on CFRunLoopRunInMode talks about running a runloop for
0 seconds, and > 0 seconds, but doesn't say anything about < 0 seconds.
Is this method call a mechanism to guarantee that the scheduled
invocation will get called and when this method returns it will have
definitively been invoked?
-joe
