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https://github.com/logos-storage/nim-datastore.git
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59 lines
1.3 KiB
Nim
59 lines
1.3 KiB
Nim
import std/atomics
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import std/locks
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type
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Semaphore* = object
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count: int
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size: int
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lock {.align: 64.}: Lock
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cond: Cond
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func `=`*(dst: var Semaphore, src: Semaphore) {.error: "A semaphore cannot be copied".}
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func `=sink`*(dst: var Semaphore, src: Semaphore) {.error: "An semaphore cannot be moved".}
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proc init*(_: type Semaphore, count: uint): Semaphore =
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var
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lock: Lock
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cond: Cond
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lock.initLock()
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cond.initCond()
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Semaphore(count: count.int, size: count.int, lock: lock, cond: cond)
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proc `=destroy`*(self: var Semaphore) =
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self.lock.deinitLock()
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self.cond.deinitCond()
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proc count*(self: var Semaphore): int =
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self.count
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proc size*(self: var Semaphore): int =
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self.size
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proc acquire*(self: var Semaphore) {.inline.} =
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self.lock.acquire()
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while self.count <= 0:
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self.cond.wait(self.lock)
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self.count -= 1
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self.lock.release()
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proc release*(self: var Semaphore) {.inline.} =
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self.lock.acquire()
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if self.count <= 0:
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self.count += 1
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self.cond.signal()
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doAssert not (self.count > self.size),
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"Semaphore count is greather than size: " & $self.size & " count is: " & $self.count
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self.lock.release()
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template withSemaphore*(self: var Semaphore, body: untyped) =
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self.acquire()
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try:
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body
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finally:
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self.release()
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