method protect-or-queue-on-recursion
Documentation for method protect-or-queue-on-recursion
assembled from the following types:
class Lock::Async
From Lock::Async
(Lock::Async) method protect-or-queue-on-recursion
Defined as:
method protect-or-queue-on-recursion(Lock::Async: )
When calling protect on a Lock::Async
instance that is already locked, the method is forced to block until the lock gets unlocked. protect-or-queue-on-recursion
avoids this issue by either behaving the same as protect if the lock is unlocked or the lock was locked by something outside the caller chain, returning Nil
, or queueing the call to &code
and returning a Promise
if the lock had already been locked at another point in the caller chain.
my Lock::Async .= new;my Int = 0;# The lock is unlocked, so the code runs instantly..protect-or-queue-on-recursion();# Here, we have caller recursion. The outer call only returns a Promise# because the inner one does. If we try to await the inner call's Promise# from the outer call, the two calls will block forever since the inner# caller's Promise return value is just the outer's with a then block..protect-or-queue-on-recursion();# Here, the lock is locked, but not by anything else on the caller chain.# This behaves just like calling protect would in this scenario.for 0..^2say ; # OUTPUT: 5