lock.jl
# This file is a part of Julia. License is MIT: http://julialang.org/license
# Advisory reentrant lock
type ReentrantLock
locked_by::Nullable{Task}
cond_wait::Condition
reentrancy_cnt::Int
ReentrantLock() = new(nothing, Condition(), 0)
end
function lock(rl::ReentrantLock)
t = current_task()
while true
if rl.reentrancy_cnt == 0
rl.locked_by = t
rl.reentrancy_cnt = 1
return
elseif t == get(rl.locked_by)
rl.reentrancy_cnt += 1
return
end
wait(rl.cond_wait)
end
end
function unlock(rl::ReentrantLock)
rl.reentrancy_cnt = rl.reentrancy_cnt - 1
if rl.reentrancy_cnt < 0
error("unlock count must match lock count")
end
if rl.reentrancy_cnt == 0
rl.locked_by = nothing
notify(rl.cond_wait)
end
return rl
end
type Semaphore
sem_size::Int
curr_cnt::Int
cond_wait::Condition
Semaphore(sem_size) = new(sem_size, 0, Condition())
end
function acquire(s::Semaphore)
while true
if s.curr_cnt < s.sem_size
s.curr_cnt = s.curr_cnt + 1
return
else
wait(s.cond_wait)
end
end
end
function release(s::Semaphore)
s.curr_cnt = s.curr_cnt - 1
notify(s.cond_wait; all=false)
end