From f0038127c83a7191970fe186d7d701dbec182f62 Mon Sep 17 00:00:00 2001
From: Dmitriy Ryajov <dryajov@gmail.com>
Date: Thu, 14 Sep 2023 17:56:02 -0600
Subject: [PATCH] remove asyncsemaphore

---
 datastore/threads/asyncsemaphore.nim | 96 ----------------------------
 datastore/threads/threadproxyds.nim  | 16 ++---
 2 files changed, 7 insertions(+), 105 deletions(-)
 delete mode 100644 datastore/threads/asyncsemaphore.nim

diff --git a/datastore/threads/asyncsemaphore.nim b/datastore/threads/asyncsemaphore.nim
deleted file mode 100644
index ee57ee0..0000000
--- a/datastore/threads/asyncsemaphore.nim
+++ /dev/null
@@ -1,96 +0,0 @@
-# Nim-datastore
-# Copyright (c) 2023 Status Research & Development GmbH
-# Licensed under either of
-#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
-#  * MIT license ([LICENSE-MIT](LICENSE-MIT))
-# at your option.
-# This file may not be copied, modified, or distributed except according to
-# those terms.
-
-{.push raises: [].}
-
-import sequtils
-import chronos, chronicles
-
-# TODO: this should probably go in chronos
-
-logScope:
-  topics = "datastore semaphore"
-
-type
-  AsyncSemaphore* = ref object of RootObj
-    size*: int
-    count: int
-    queue: seq[Future[void]]
-
-proc new*(_: type AsyncSemaphore, size: int): AsyncSemaphore =
-  AsyncSemaphore(size: size, count: size)
-
-proc `count`*(s: AsyncSemaphore): int = s.count
-
-proc tryAcquire*(s: AsyncSemaphore): bool =
-  ## Attempts to acquire a resource, if successful
-  ## returns true, otherwise false
-  ##
-
-  if s.count > 0 and s.queue.len == 0:
-    s.count.dec
-    trace "Acquired slot", available = s.count, queue = s.queue.len
-    return true
-
-proc acquire*(s: AsyncSemaphore): Future[void] =
-  ## Acquire a resource and decrement the resource
-  ## counter. If no more resources are available,
-  ## the returned future will not complete until
-  ## the resource count goes above 0.
-  ##
-
-  let fut = newFuture[void]("AsyncSemaphore.acquire")
-  if s.tryAcquire():
-    fut.complete()
-    return fut
-
-  proc cancellation(udata: pointer) {.gcsafe.} =
-    fut.cancelCallback = nil
-    if not fut.finished:
-      s.queue.keepItIf( it != fut )
-
-  fut.cancelCallback = cancellation
-
-  s.queue.add(fut)
-
-  trace "Queued slot", available = s.count, queue = s.queue.len
-  return fut
-
-proc forceAcquire*(s: AsyncSemaphore) =
-  ## ForceAcquire will always succeed,
-  ## creating a temporary slot if required.
-  ## This temporary slot will stay usable until
-  ## there is less `acquire`s than `release`s
-  s.count.dec
-
-proc release*(s: AsyncSemaphore) =
-  ## Release a resource from the semaphore,
-  ## by picking the first future from the queue
-  ## and completing it and incrementing the
-  ## internal resource count
-  ##
-
-  doAssert(s.count <= s.size)
-
-  if s.count < s.size:
-    trace "Releasing slot", available = s.count,
-                            queue = s.queue.len
-
-    s.count.inc
-    while s.queue.len > 0:
-      var fut = s.queue[0]
-      s.queue.delete(0)
-      if not fut.finished():
-        s.count.dec
-        fut.complete()
-        break
-
-    trace "Released slot", available = s.count,
-                           queue = s.queue.len
-    return
diff --git a/datastore/threads/threadproxyds.nim b/datastore/threads/threadproxyds.nim
index d3ae21a..09f448f 100644
--- a/datastore/threads/threadproxyds.nim
+++ b/datastore/threads/threadproxyds.nim
@@ -21,7 +21,6 @@ import ../key
 import ../query
 import ../datastore
 
-import ./asyncsemaphore
 import ./databuffer
 
 type
@@ -36,15 +35,17 @@ type
   ThreadDatastore* = ref object of Datastore
     tp: Taskpool
     ds: Datastore
-    semaphore: AsyncSemaphore
     tasks: seq[Future[void]]
 
-template dispatchTask(self: ThreadDatastore, ctx: TaskCtx, runTask: proc): untyped =
+template dispatchTask(
+  self: ThreadDatastore,
+  ctx: TaskCtx,
+  runTask: proc): untyped =
+
   let
     fut = wait(ctx.signal)
 
   try:
-    await self.semaphore.acquire()
     runTask()
     self.tasks.add(fut)
     await fut
@@ -58,8 +59,6 @@ template dispatchTask(self: ThreadDatastore, ctx: TaskCtx, runTask: proc): untyp
       idx != -1):
       self.tasks.del(idx)
 
-    self.semaphore.release()
-
 proc hasTask(
   ctx: ptr TaskCtx,
   key: ptr Key) =
@@ -223,7 +222,7 @@ method close*(self: ThreadDatastore): Future[?!void] {.async.} =
 
   await self.ds.close()
 
-proc queryTask*(
+proc queryTask(
   ctx: ptr TaskCtx,
   iter: ptr QueryIter) =
 
@@ -303,5 +302,4 @@ func new*(
 
   success ThreadDatastore(
     tp: tp,
-    ds: ds,
-    semaphore: AsyncSemaphore.new(tp.numThreads - 1)) # one thread is needed for the task dispatcher
+    ds: ds)