big rename: Promise -> FlowVar

lib/pure/concurrency/threadpool.nim

@@ -90,8 +90,8 @@ type
     cv: CondVar
     idx: int
 
-  RawPromise* = ref RawPromiseObj ## untyped base class for 'Promise[T]'
-  RawPromiseObj = object of TObject
+  RawFlowVar* = ref RawFlowVarObj ## untyped base class for 'FlowVar[T]'
+  RawFlowVarObj = object of TObject
     ready, usesCondVar: bool
     cv: CondVar #\
     # for 'awaitAny' support
@@ -100,10 +100,10 @@ type
     data: pointer  # we incRef and unref it to keep it alive
     owner: pointer # ptr Worker
 
-  PromiseObj[T] = object of RawPromiseObj
+  FlowVarObj[T] = object of RawFlowVarObj
     blob: T
 
-  Promise*{.compilerProc.}[T] = ref PromiseObj[T]
+  FlowVar*{.compilerProc.}[T] = ref FlowVarObj[T] ## a data flow variable
 
   ToFreeQueue = object
     len: int
@@ -123,28 +123,28 @@ type
     shutdown: bool # the pool requests to shut down this worker thread
     q: ToFreeQueue
 
-proc await*(prom: RawPromise) =
-  ## waits until the value for the promise arrives. Usually it is not necessary
+proc await*(fv: RawFlowVar) =
+  ## waits until the value for the flowVar arrives. Usually it is not necessary
   ## to call this explicitly.
-  if prom.usesCondVar:
-    prom.usesCondVar = false
-    await(prom.cv)
-    destroyCondVar(prom.cv)
+  if fv.usesCondVar:
+    fv.usesCondVar = false
+    await(fv.cv)
+    destroyCondVar(fv.cv)
 
-proc finished(prom: RawPromise) =
-  doAssert prom.ai.isNil, "promise is still attached to an 'awaitAny'"
-  # we have to protect against the rare cases where the owner of the promise
-  # simply disregards the promise and yet the "promiser" has not yet written
+proc finished(fv: RawFlowVar) =
+  doAssert fv.ai.isNil, "flowVar is still attached to an 'awaitAny'"
+  # we have to protect against the rare cases where the owner of the flowVar
+  # simply disregards the flowVar and yet the "flowVarr" has not yet written
   # anything to it:
-  await(prom)
-  if prom.data.isNil: return
-  let owner = cast[ptr Worker](prom.owner)
+  await(fv)
+  if fv.data.isNil: return
+  let owner = cast[ptr Worker](fv.owner)
   let q = addr(owner.q)
   var waited = false
   while true:
     acquire(q.lock)
     if q.len < q.data.len:
-      q.data[q.len] = prom.data
+      q.data[q.len] = fv.data
       inc q.len
       release(q.lock)
       break
@@ -153,11 +153,11 @@ proc finished(prom: RawPromise) =
       release(q.lock)
       wait(q.empty, q.lock)
       waited = true
-  prom.data = nil
+  fv.data = nil
   # wakeup other potentially waiting threads:
   if waited: signal(q.empty)
 
-proc cleanPromises(w: ptr Worker) =
+proc cleanFlowVars(w: ptr Worker) =
   let q = addr(w.q)
   acquire(q.lock)
   for i in 0 .. <q.len:
@@ -166,72 +166,72 @@ proc cleanPromises(w: ptr Worker) =
   release(q.lock)
   signal(q.empty)
 
-proc promFinalizer[T](prom: Promise[T]) = finished(prom)
+proc fvFinalizer[T](fv: FlowVar[T]) = finished(fv)
 
-proc nimCreatePromise[T](): Promise[T] {.compilerProc.} =
-  new(result, promFinalizer)
+proc nimCreateFlowVar[T](): FlowVar[T] {.compilerProc.} =
+  new(result, fvFinalizer)
 
-proc nimPromiseCreateCondVar(prom: RawPromise) {.compilerProc.} =
-  prom.cv = createCondVar()
-  prom.usesCondVar = true
+proc nimFlowVarCreateCondVar(fv: RawFlowVar) {.compilerProc.} =
+  fv.cv = createCondVar()
+  fv.usesCondVar = true
 
-proc nimPromiseSignal(prom: RawPromise) {.compilerProc.} =
-  if prom.ai != nil:
-    acquire(prom.ai.cv.L)
-    prom.ai.idx = prom.idx
-    inc prom.ai.cv.counter
-    release(prom.ai.cv.L)
-    signal(prom.ai.cv.c)
-  if prom.usesCondVar: signal(prom.cv)
+proc nimFlowVarSignal(fv: RawFlowVar) {.compilerProc.} =
+  if fv.ai != nil:
+    acquire(fv.ai.cv.L)
+    fv.ai.idx = fv.idx
+    inc fv.ai.cv.counter
+    release(fv.ai.cv.L)
+    signal(fv.ai.cv.c)
+  if fv.usesCondVar: signal(fv.cv)
 
-proc awaitAndThen*[T](prom: Promise[T]; action: proc (x: T) {.closure.}) =
-  ## blocks until the ``prom`` is available and then passes its value
+proc awaitAndThen*[T](fv: FlowVar[T]; action: proc (x: T) {.closure.}) =
+  ## blocks until the ``fv`` is available and then passes its value
   ## to ``action``. Note that due to Nimrod's parameter passing semantics this
   ## means that ``T`` doesn't need to be copied and so ``awaitAndThen`` can
   ## sometimes be more efficient than ``^``.
-  await(prom)
+  await(fv)
   when T is string or T is seq:
-    action(cast[T](prom.data))
+    action(cast[T](fv.data))
   elif T is ref:
-    {.error: "'awaitAndThen' not available for Promise[ref]".}
+    {.error: "'awaitAndThen' not available for FlowVar[ref]".}
   else:
-    action(prom.blob)
-  finished(prom)
+    action(fv.blob)
+  finished(fv)
 
-proc `^`*[T](prom: Promise[ref T]): foreign ptr T =
+proc `^`*[T](fv: FlowVar[ref T]): foreign ptr T =
   ## blocks until the value is available and then returns this value.
-  await(prom)
-  result = cast[foreign ptr T](prom.data)
+  await(fv)
+  result = cast[foreign ptr T](fv.data)
 
-proc `^`*[T](prom: Promise[T]): T =
+proc `^`*[T](fv: FlowVar[T]): T =
   ## blocks until the value is available and then returns this value.
-  await(prom)
+  await(fv)
   when T is string or T is seq:
-    result = cast[T](prom.data)
+    result = cast[T](fv.data)
   else:
-    result = prom.blob
+    result = fv.blob
 
-proc awaitAny*(promises: openArray[RawPromise]): int =
-  ## awaits any of the given promises. Returns the index of one promise for
-  ## which a value arrived. A promise only supports one call to 'awaitAny' at
+proc awaitAny*(flowVars: openArray[RawFlowVar]): int =
+  ## awaits any of the given flowVars. Returns the index of one flowVar for
+  ## which a value arrived. A flowVar only supports one call to 'awaitAny' at
   ## the same time. That means if you await([a,b]) and await([b,c]) the second
-  ## call will only await 'c'. If there is no promise left to be able to wait
+  ## call will only await 'c'. If there is no flowVar left to be able to wait
   ## on, -1 is returned.
   ## **Note**: This results in non-deterministic behaviour and so should be
   ## avoided.
   var ai: AwaitInfo
   ai.cv = createCondVar()
   var conflicts = 0
-  for i in 0 .. promises.high:
-    if cas(addr promises[i].ai, nil, addr ai):
-      promises[i].idx = i
+  for i in 0 .. flowVars.high:
+    if cas(addr flowVars[i].ai, nil, addr ai):
+      flowVars[i].idx = i
     else:
       inc conflicts
-  if conflicts < promises.len:
+  if conflicts < flowVars.len:
     await(ai.cv)
     result = ai.idx
-    for i in 0 .. promises.high:
-      discard cas(addr promises[i].ai, addr ai, nil)
+    for i in 0 .. flowVars.high:
+      discard cas(addr flowVars[i].ai, addr ai, nil)
   else:
     result = -1
   destroyCondVar(ai.cv)
@@ -259,7 +259,7 @@ proc slave(w: ptr Worker) {.thread.} =
     await(w.taskArrived)
     assert(not w.ready)
     w.f(w, w.data)
-    if w.q.len != 0: w.cleanPromises
+    if w.q.len != 0: w.cleanFlowVars
     if w.shutdown:
       w.shutdown = false
       atomicDec currentPoolSize
@@ -300,7 +300,7 @@ proc spawn*(call: expr): expr {.magic: "Spawn".}
   ## always spawns a new task, so that the 'call' is never executed on
   ## the calling thread. 'call' has to be proc call 'p(...)' where 'p'
   ## is gcsafe and has a return type that is either 'void' or compatible
-  ## with ``Promise[T]``.
+  ## with ``FlowVar[T]``.
 
 template spawnX*(call: expr): expr =
   ## spawns a new task if a CPU core is ready, otherwise executes the
@@ -308,7 +308,7 @@ template spawnX*(call: expr): expr =
   ## use 'spawn' in order to not block the producer for an unknown
   ## amount of time. 'call' has to be proc call 'p(...)' where 'p'
   ## is gcsafe and has a return type that is either 'void' or compatible
-  ## with ``Promise[T]``.
+  ## with ``FlowVar[T]``.
   (if preferSpawn(): spawn call else: call)
 
 proc parallel*(body: stmt) {.magic: "Parallel".}