Add retryable feature.

[inamiy]

This pull request brings a new retryable feature for future ver 2.1.0.

task.try(n) returns a new task that is retryable for n-1 times, and is conceptually equal to

task.failure(clonedTask1).failure(clonedTask2)...

with n-1 failure-able.

Usage

task.try(3).success { ...
    // this closure will be called even when task is rejected for 1st & 2nd try 
    // but fulfilled in 3rd try.
}

// shorthand
(task ~ 3).then { ... }

[inamiy]

• Test for progress, pause, cancel
• Write README.md

[inamiy]

Ready to

[tspanindra]

Can i do task.try(3) after certain seconds? i mean can i introduce delay between each retry?

[inamiy]

@panindra1
Unfortunately, no.
SwiftTask is not in charge of handling any timing controls.

Instead, you can implement on your own like this:

func taskWithDelay(delay: Float) -> Task<P, V, E> {
    return Task { ...
        dispatch_after(...) {
             // your task implementation here (after delay) 
        }
    }
}

// retry at most 1000 times, starting with delay=0 and then 3 sec each
taskWithDelay(0).failure { ... in taskWithDelay(3).try(1000-1) }

[tspanindra]

Wow..Thank you very much!