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ircd::ctx: Add when_any() / when_all().

This commit is contained in:
Jason Volk 2018-03-10 17:33:14 -08:00
parent 07c1356dae
commit a2be4d3ee5

View file

@ -20,6 +20,8 @@ namespace ircd::ctx
template<class... T> struct scoped_future;
enum class future_status;
template<class it> future<it> when_any(it first, const it &last);
template<class it> future<void> when_all(it first, const it &last);
}
enum class ircd::ctx::future_status
@ -359,3 +361,61 @@ ircd::ctx::wait_until(const future<T> &f,
future_status::ready:
future_status::deferred;
}
template<class it>
ircd::ctx::future<void>
ircd::ctx::when_all(it first,
const it &last)
{
promise<void> p;
future<void> ret(p);
for(; first != last; ++first)
if(pending(first->st))
first->st.then = [p](shared_state_base &) mutable
{
if(!p.valid())
return;
if(refcount(*p.st) < 2)
return p.set_value();
return remove(*p.st, p);
};
if(refcount(*p.st) <= 1)
p.set_value();
return ret;
}
template<class it>
ircd::ctx::future<it>
ircd::ctx::when_any(it first,
const it &last)
{
promise<it> p;
future<it> ret(p);
for(auto first_(first); first_ != last; ++first_)
if(ready(first_->st))
{
set_observed(first_->st);
p.set_value(first_);
return ret;
}
for(; first != last; ++first)
if(pending(first->st))
first->st.then = [p, first](shared_state_base &) mutable
{
if(!p.valid())
return;
set_observed(first->st);
p.set_value(first);
};
if(refcount(*p.st) <= 1)
p.set_value(first);
return ret;
}