mirror of
https://github.com/nim-lang/Nim.git
synced 2025-12-29 01:14:41 +00:00
f51613e262
* make sink operator optional * bug fix, add changelog entry * Trigger build * fix one regression * fix test * Trigger build * fix typos
44 lines
1.1 KiB
Nim
44 lines
1.1 KiB
Nim
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type
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SharedPtr*[T] = object
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val: ptr tuple[atomicCounter: int, value: T]
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proc `=destroy`*[T](p: var SharedPtr[T]) =
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mixin `=destroy`
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if p.val != nil:
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let c = atomicDec(p.val[].atomicCounter)
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if c == 0:
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`=destroy`(p.val.value)
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freeShared(p.val)
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p.val = nil
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proc `=`*[T](dest: var SharedPtr[T], src: SharedPtr[T]) {.inline.} =
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if dest.val != src.val:
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if dest.val != nil:
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`=destroy`(dest)
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if src.val != nil:
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discard atomicInc(src.val[].atomicCounter)
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dest.val = src.val
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proc newSharedPtr*[T](val: sink T): SharedPtr[T] =
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result.val = cast[type(result.val)](allocShared0(sizeof(result.val[])))
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result.val.atomicCounter = 1
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result.val.value = val
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func get*[T](p: SharedPtr[T]): var T {.inline.} =
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p.val.value
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func isNil*[T](p: SharedPtr[T]): bool {.inline.} =
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p.val == nil
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proc cas*[T](p, old_val: var SharedPtr[T], new_val: SharedPtr[T]): bool {.inline.} =
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if old_val.val == new_val.val:
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result = true
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else:
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result = cas(p.val.addr, old_val.val, new_val.val)
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if result:
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`=destroy`(old_val)
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if new_val.val != nil:
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discard atomicInc(new_val.val[].atomicCounter)
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