mirror of
https://github.com/nim-lang/Nim.git
synced 2026-01-01 02:42:05 +00:00
50 lines
1.3 KiB
Nim
50 lines
1.3 KiB
Nim
|
|
type
|
|
SharedPtr*[T] = object
|
|
val: ptr tuple[atomicCounter: int, value: T]
|
|
|
|
proc `=destroy`*[T](p: var SharedPtr[T]) =
|
|
mixin `=destroy`
|
|
if p.val != nil:
|
|
let c = atomicDec(p.val[].atomicCounter)
|
|
if c == 0:
|
|
`=destroy`(p.val.value)
|
|
freeShared(p.val)
|
|
p.val = nil
|
|
|
|
proc `=`*[T](dest: var SharedPtr[T], src: SharedPtr[T]) {.inline.} =
|
|
if dest.val != src.val:
|
|
if dest.val != nil:
|
|
`=destroy`(dest)
|
|
if src.val != nil:
|
|
discard atomicInc(src.val[].atomicCounter)
|
|
dest.val = src.val
|
|
|
|
proc `=sink`*[T](dest: var SharedPtr[T], src: SharedPtr[T]) {.inline.} =
|
|
if dest.val != src.val:
|
|
if dest.val != nil:
|
|
`=destroy`(dest)
|
|
dest.val = src.val
|
|
|
|
proc newSharedPtr*[T](val: sink T): SharedPtr[T] =
|
|
result.val = cast[type(result.val)](allocShared0(sizeof(result.val[])))
|
|
result.val.atomicCounter = 1
|
|
result.val.value = val
|
|
|
|
func get*[T](p: SharedPtr[T]): var T {.inline.} =
|
|
p.val.value
|
|
|
|
func isNil*[T](p: SharedPtr[T]): bool {.inline.} =
|
|
p.val == nil
|
|
|
|
proc cas*[T](p, old_val: var SharedPtr[T], new_val: SharedPtr[T]): bool {.inline.} =
|
|
if old_val.val == new_val.val:
|
|
result = true
|
|
else:
|
|
result = cas(p.val.addr, old_val.val, new_val.val)
|
|
if result:
|
|
`=destroy`(old_val)
|
|
if new_val.val != nil:
|
|
discard atomicInc(new_val.val[].atomicCounter)
|
|
|