/* msreader.m: Reads from multiple sockets the hard way.
* *** DON'T DO THIS - see mspoller.m for a better example. *** */
#import "ZMQObjC.h"
static NSString *const kTaskVentEndpoint = @"tcp://localhost:5557";
static NSString *const kWeatherServerEndpoint = @"tcp://localhost:5556";
#define MSEC_PER_NSEC (1000000)
int
main(void)
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
ZMQContext *ctx = [[[ZMQContext alloc] initWithIOThreads:1U] autorelease];
/* Connect to task ventilator. */
ZMQSocket *receiver = [ctx socketWithType:ZMQ_PULL];
[receiver connectToEndpoint:kTaskVentEndpoint];
/* Connect to weather server. */
ZMQSocket *subscriber = [ctx socketWithType:ZMQ_SUB];
[subscriber connectToEndpoint:kWeatherServerEndpoint];
NSData *subData = [@"10001" dataUsingEncoding:NSUTF8StringEncoding];
[subscriber setData:subData forOption:ZMQ_SUBSCRIBE];
/* Process messages from both sockets, prioritizing the task vent. */
/* Could fair queue by checking each socket for activity in turn, rather
* than continuing to service the current socket as long as it is busy. */
struct timespec msec = {0, MSEC_PER_NSEC};
for (;;) {
/* Worst case: a task is always pending and we never get to weather,
* or vice versa. In such a case, memory use would rise without
* limit if we did not ensure the objects autoreleased by a single loop
* will be autoreleased whether we leave or continue in the loop. */
NSAutoreleasePool *p;
/* Process any waiting tasks. */
for (p = [[NSAutoreleasePool alloc] init];
nil != [receiver receiveDataWithFlags:ZMQ_NOBLOCK];
[p drain], p = [[NSAutoreleasePool alloc] init]);
[p drain];
/* No waiting tasks - process any waiting weather updates. */
for (p = [[NSAutoreleasePool alloc] init];
nil != [subscriber receiveDataWithFlags:ZMQ_NOBLOCK];
[p drain], p = [[NSAutoreleasePool alloc] init]);
[p drain];
/* Nothing doing - sleep for a millisecond. */
(void)nanosleep(&msec, NULL);
}
/* NOT REACHED */
[ctx closeSockets];
[pool drain]; /* This finally releases the autoreleased context. */
return EXIT_SUCCESS;
}