626075ca34
This PR adds a shared mutex (or read-write lock) as `Std.SharedMutex`. In order to easily migrate a `Std.Mutex` to `Std.SharedMutex` if necessary, the functions for obtaining exclusive access are named the same, allowing a correct drop in to be done by just swapping types.
114 lines
3.8 KiB
Text
114 lines
3.8 KiB
Text
import Std.Sync.SharedMutex
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def countIt (mutex : Std.SharedMutex Nat) : IO Unit := do
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for _ in [0:1000] do
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mutex.atomically do
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modify fun s => s + 1
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def atomically : IO Unit := do
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let mutex ← Std.SharedMutex.new 0
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let t1 ← IO.asTask (prio := .dedicated) (countIt mutex)
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let t2 ← IO.asTask (prio := .dedicated) (countIt mutex)
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let t3 ← IO.asTask (prio := .dedicated) (countIt mutex)
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let t4 ← IO.asTask (prio := .dedicated) (countIt mutex)
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IO.ofExcept t1.get
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IO.ofExcept t2.get
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IO.ofExcept t3.get
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IO.ofExcept t4.get
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mutex.atomically do
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let val ← get
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if val != 4000 then
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throw <| .userError s!"Should be 4000 but was {val}"
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def holdIt (mutex : Std.SharedMutex Nat) (ref : IO.Ref Nat) : IO Unit := do
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mutex.atomically do
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ref.set 1
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modify fun s => s + 1
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while (← ref.get) == 1 do
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IO.sleep 1
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def tryIt (mutex : Std.SharedMutex Nat) (ref : IO.Ref Nat) : IO Unit := do
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while (← ref.get) == 0 do
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IO.sleep 1
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let success ← mutex.tryAtomically (modify fun s => s + 1)
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if success.isSome then throw <| .userError s!"lock succeeded but shouldn't"
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ref.set 2
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mutex.atomically (modify fun s => s + 1)
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let success ← mutex.tryAtomically (modify fun s => s + 1)
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if success.isNone then throw <| .userError s!"lock didn't succeed but should"
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def tryAtomically : IO Unit := do
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let mutex ← Std.SharedMutex.new 0
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let ref ← IO.mkRef 0
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let t1 ← IO.asTask (prio := .dedicated) (holdIt mutex ref)
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let t2 ← IO.asTask (prio := .dedicated) (tryIt mutex ref)
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IO.ofExcept t1.get
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IO.ofExcept t2.get
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mutex.atomically do
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let val ← get
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if val != 3 then
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throw <| .userError s!"Should be 3 but was {val}"
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def readIt (mutex : Std.SharedMutex Nat) : IO Unit := do
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mutex.atomicallyRead do
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let val ← read
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if val != 37 then
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throw <| .userError s!"Value should be 37 but was {val}"
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def atomicallyRead : IO Unit := do
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let mutex ← Std.SharedMutex.new 37
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let t1 ← IO.asTask (prio := .dedicated) (readIt mutex)
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let t2 ← IO.asTask (prio := .dedicated) (readIt mutex)
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IO.ofExcept t1.get
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IO.ofExcept t2.get
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def tryWriteIt (mutex : Std.SharedMutex Nat) (ref : IO.Ref Nat) : IO Unit := do
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let success ←
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mutex.tryAtomically do
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ref.set 1
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modify fun s => s + 1
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while (← ref.get) == 1 do
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IO.sleep 1
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if success.isNone then throw <| .userError s!"write lock failed"
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def tryReadIt (mutex : Std.SharedMutex Nat) (ref : IO.Ref Nat) : IO Unit := do
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while (← ref.get) == 0 do
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IO.sleep 1
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let success ← mutex.tryAtomically (modify fun s => s + 1)
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if success.isSome then throw <| .userError s!"write lock succeeded but shouldn't"
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let success ← mutex.tryAtomicallyRead read
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if success.isSome then throw <| .userError s!"read lock succeeded but shouldn't"
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ref.set 2
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let val ← mutex.atomicallyRead read
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if val != 1 then throw <| .userError s!"value should be 1 but was {val}"
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mutex.atomicallyRead do
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ref.set 3
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while (← ref.get) == 3 do
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IO.sleep 1
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def tryReadIt' (mutex : Std.SharedMutex Nat) (ref : IO.Ref Nat) : IO Unit := do
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while (← ref.get) != 3 do
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IO.sleep 1
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let val ← mutex.tryAtomicallyRead read
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if val != some 1 then throw <| .userError s!"value should be `some 1` but was {val}"
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ref.set 4
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def tryAtomicallyRead : IO Unit := do
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let mutex ← Std.SharedMutex.new 0
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let ref ← IO.mkRef 0
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let t1 ← IO.asTask (prio := .dedicated) (tryWriteIt mutex ref)
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let t2 ← IO.asTask (prio := .dedicated) (tryReadIt mutex ref)
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let t3 ← IO.asTask (prio := .dedicated) (tryReadIt' mutex ref)
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IO.ofExcept t1.get
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IO.ofExcept t2.get
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IO.ofExcept t3.get
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mutex.atomically do
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let val ← get
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if val != 1 then
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throw <| .userError s!"Should be 1 but was {val}"
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#eval atomically
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#eval atomicallyRead
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#eval tryAtomically
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#eval tryAtomicallyRead
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