Palestra sobre Grand Central Dispatch no [self sp]

Diego Chohfi - @dchohfi

Diego Chohfi Turini

[self SP];

Paralelismo transparenteGCD(Grande Central Dispatcher)

Monday, March 19, 12

http://selfsp.org/

http://selfsp.org/


“Quando precisamos de paralelismo temos n problemas, e quando usamos temos n^2 problemas”- @qmx



^Primeiro:Blocos



int (^bloco)(int) = ^(int numero){ return numero *10;};

retorno

variável

paramêtro

broco

nome param

corpo do broco

Véi, na boa.. bloco?



Bloco = tipo

typedef double(^Dividir)(double, double);

@property (copy) Dividir dividir;

dividir = ^( double dividendo, double divisor){return dividendo / divisor;

}; NSLog(@"%f.0", self.dividir(10,2));



int variavelExterna = 10; void (^block)(int) = ^(int mother){ NSLog(@"OF JOBS %i, guardei escopo!", modern * variavelExterna); }; block(10);

NSArray *OMG = [[NSArray alloc] initWithObjects:@"MOTHER", @"OF", @"JOBS", nil];

[OMG enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) { NSLog(obj); }];

TWTweetComposeViewController *tweet = [[TWTweetComposeViewController alloc] init]; [tweet setCompletionHandler:^(TWTweetComposeViewControllerResult result){ if(result == TWTweetComposeViewControllerResultDone){ NSLog(@"AI QUE LOUCURA, TWEETEI"); } }];



GCD, it’s all about queueing(based on kqueue)



dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

dispatch_async(queue, ^{ NSLog(@"Calculando o tamanho do universo, no iPhone 3");});

#define! DISPATCH_QUEUE_PRIORITY_HIGH ! 2#define! DISPATCH_QUEUE_PRIORITY_DEFAULT 0#define! DISPATCH_QUEUE_PRIORITY_LOW ! (-2)#define! DISPATCH_QUEUE_PRIORITY_BACKGROUND! INT16_MIN



Criando queue’s

dispatch_queue_t minhaQueue = dispatch_queue_create("br.com.caelum", NULL); dispatch_async(minhaQueue, ^{ });



dispatch_async(queue, ^{ [NSThread sleepForTimeInterval:2];

asyncLabel.text = @"UNIVERSO CALCULADO";});

syncLabel.text = @"Calculando o universo";

Alterando views, cuidado!

dispatch_async(queue, ^{[NSThread sleepForTimeInterval:2];dispatch_async(dispatch_get_main_queue(), ^{

asynchLabel.text = @"UNIVERSO CALCULADO";});

}); syncLabel.text = @"Calculando o universo";



Criando Grupos

dispatch_group_t group = dispatch_group_create();

dispatch_group_async(group,queue,^{ [NSThread sleepForTimeInterval:1];

NSLog(@"Calculando o tamanho do sol");});

dispatch_group_async(group,queue,^{NSLog(@"Esperando a mulher fazer compras");

});

dispatch_group_notify(group,queue,^{NSLog(@"Será executado após os dois blocos");

});



dispatch_async(queue,^{[NSThread sleepForTimeInterval:1];for (int i=0; i<10; i++) {

valorMagico++;}

});

Valores fora do escopo

__blockint valorMagico = 0;



dispatch_queue_t queue = dispatch_get_global_queue(0, 0); dispatch_apply(10, queue, ^(size_t i){

NSLog(@"Numero: %zu", i);//não garante ordem});

Batch queueing


Documents

Palestra sobre Grand Central Dispatch no [self sp]