From 7f112566f88333472ad22cafa88e0d3d1ae34857 Mon Sep 17 00:00:00 2001
From: Jaremy Creechley <creechley@gmail.com>
Date: Thu, 14 Sep 2023 13:52:35 -0700
Subject: [PATCH] trying out manual futures

---
 datastore/threadproxyds.nim         |  15 --
 datastore/threads/sharedptr.nim     |   2 +-
 datastore/threads/then.nim          | 209 ++++++++++++++++++++++++++++
 datastore/threads/threadbackend.nim |  47 +++++--
 results.rb                          | 112 +++++++++++++++
 5 files changed, 361 insertions(+), 24 deletions(-)
 create mode 100644 datastore/threads/then.nim
 create mode 100644 results.rb

diff --git a/datastore/threadproxyds.nim b/datastore/threadproxyds.nim
index 20fe110..139caa7 100644
--- a/datastore/threadproxyds.nim
+++ b/datastore/threadproxyds.nim
@@ -94,21 +94,6 @@ method put*(
 
   block:
     put(ret, self.tds, key, data)
-    echo "\n"
-    echoed "wait put thr: ", $getThreadId()
-    echo "\n"
-    await sleepAsync(400.milliseconds)
-    await wait(ret)
-    echo "\n"
-    await sleepAsync(400.milliseconds)
-
-    answer = ret.convert(void)
-  block:
-    echo "\n"
-    await sleepAsync(400.milliseconds)
-    echoed "PUT RELEASE"
-    echo "PUT RELEASE"
-    ret.release()
   
   return answer
 
diff --git a/datastore/threads/sharedptr.nim b/datastore/threads/sharedptr.nim
index 859df5c..cede20c 100644
--- a/datastore/threads/sharedptr.nim
+++ b/datastore/threads/sharedptr.nim
@@ -69,7 +69,7 @@ proc decr*[T](x: var SharedPtr[T]) =
     else:
       echoed "SharedPtr: decr: ", x.container.pointer.repr, " cnt: ", x.container.cnt, " tp: ", $(typeof(T))
 
-template release*[T](x: var SharedPtr[T]) =
+proc release*[T](x: var SharedPtr[T]) =
   echoed "SharedPtr: release: ", $(typeof(T))
   x.decr()
   x.container = nil
diff --git a/datastore/threads/then.nim b/datastore/threads/then.nim
new file mode 100644
index 0000000..d98d461
--- /dev/null
+++ b/datastore/threads/then.nim
@@ -0,0 +1,209 @@
+import pkg/chronos
+import pkg/questionable
+import pkg/questionable/results
+import pkg/upraises
+
+## duplicate of codex/utils/then.nim
+
+# Similar to JavaScript's Promise API, `.then` and `.catch` can be used to
+# handle results and errors of async `Futures` within a synchronous closure.
+# They can be used as an alternative to `asyncSpawn` which does not return a
+# value and will raise a `FutureDefect` if there are unhandled errors
+# encountered. Both `.then` and `.catch` act as callbacks that do not block the
+# synchronous closure's flow.
+
+# `.then` is called when the `Future` is successfully completed and can be
+# chained as many times as desired, calling each `.then` callback in order. When
+# the `Future` returns `Result[T, ref CatchableError]` (or `?!T`), the value
+# called in the `.then` callback will be unpacked from the `Result` as a
+# convenience. In other words, for `Future[?!T]`, the `.then` callback will take
+# a single parameter `T`. See `tests/utils/testthen.nim` for more examples. To
+# allow for chaining, `.then` returns its future. If the future is already
+# complete, the `.then` callback will be executed immediately.
+
+# `.catch` is called when the `Future` fails. In the case when the `Future`
+# returns a `Result[T, ref CatchableError` (or `?!T`), `.catch` will be called
+# if the `Result` contains an error. If the `Future` is already failed (or
+# `Future[?!T]` contains an error), the `.catch` callback will be executed
+# immediately.
+
+# `.cancelled` is called when the `Future` is cancelled. If the `Future` is
+# already cancelled, the `.cancelled` callback will be executed immediately.
+
+# More info on JavaScript's Promise API can be found at:
+# https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+runnableExamples:
+  proc asyncProc(): Future[int] {.async.} =
+    await sleepAsync(1.millis)
+    return 1
+
+  asyncProc()
+    .then(proc(i: int) = echo "returned ", i)
+    .catch(proc(e: ref CatchableError) = doAssert false, "will not be triggered")
+
+  # outputs "returned 1"
+
+  proc asyncProcWithError(): Future[int] {.async.} =
+    await sleepAsync(1.millis)
+    raise newException(ValueError, "some error")
+
+  asyncProcWithError()
+    .then(proc(i: int) = doAssert false, "will not be triggered")
+    .catch(proc(e: ref CatchableError) = echo "errored: ", e.msg)
+
+  # outputs "errored: some error"
+
+type
+  OnSuccess*[T] = proc(val: T) {.gcsafe, upraises: [].}
+  OnError* = proc(err: ref CatchableError) {.gcsafe, upraises: [].}
+  OnCancelled* = proc() {.gcsafe, upraises: [].}
+
+proc ignoreError(err: ref CatchableError) = discard
+proc ignoreCancelled() = discard
+
+template handleFinished(future: FutureBase,
+                        onError: OnError,
+                        onCancelled: OnCancelled) =
+
+  if not future.finished:
+    return
+
+  if future.cancelled:
+    onCancelled()
+    return
+
+  if future.failed:
+    onError(future.error)
+    return
+
+proc then*(future: Future[void], onSuccess: OnSuccess[void]): Future[void] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, ignoreCancelled)
+    onSuccess()
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
+
+proc then*[T](future: Future[T], onSuccess: OnSuccess[T]): Future[T] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, ignoreCancelled)
+
+    if val =? future.read.catch:
+      onSuccess(val)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
+
+proc then*[T](future: Future[?!T], onSuccess: OnSuccess[T]): Future[?!T] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, ignoreCancelled)
+
+    try:
+      if val =? future.read:
+        onSuccess(val)
+    except CatchableError as e:
+      ignoreError(e)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
+
+proc then*(future: Future[?!void], onSuccess: OnSuccess[void]): Future[?!void] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, ignoreCancelled)
+
+    try:
+      if future.read.isOk:
+        onSuccess()
+    except CatchableError as e:
+      ignoreError(e)
+      return
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
+
+proc catch*[T](future: Future[T], onError: OnError) =
+
+  if future.isNil: return
+
+  proc cb(udata: pointer) =
+    future.handleFinished(onError, ignoreCancelled)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+
+proc catch*[T](future: Future[?!T], onError: OnError) =
+
+  if future.isNil: return
+
+  proc cb(udata: pointer) =
+    future.handleFinished(onError, ignoreCancelled)
+
+    try:
+      if err =? future.read.errorOption:
+        onError(err)
+    except CatchableError as e:
+      onError(e)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+
+proc cancelled*[T](future: Future[T], onCancelled: OnCancelled): Future[T] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, onCancelled)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+    onCancelled()
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
+
+proc cancelled*[T](future: Future[?!T], onCancelled: OnCancelled): Future[?!T] =
+
+  proc cb(udata: pointer) =
+    future.handleFinished(ignoreError, onCancelled)
+
+  proc cancellation(udata: pointer) =
+    if not future.finished():
+      future.removeCallback(cb)
+    onCancelled()
+
+  future.addCallback(cb)
+  future.cancelCallback = cancellation
+  return future
\ No newline at end of file
diff --git a/datastore/threads/threadbackend.nim b/datastore/threads/threadbackend.nim
index a33d610..0e69f2e 100644
--- a/datastore/threads/threadbackend.nim
+++ b/datastore/threads/threadbackend.nim
@@ -122,6 +122,7 @@ proc get*(
 import std/os
 
 proc putTask*(
+  sig: SharedSignal,
   ret: TResult[void],
   tds: ThreadDatastorePtr,
   kb: KeyBuffer,
@@ -145,22 +146,52 @@ proc putTask*(
   else:
     ret.success()
 
-  discard ret.fireSync()
+  discard sig.fireSync()
   # ret.release()
   echoed "putTask: FINISH\n"
 
+import then
+
 proc put*(
-  ret: var TResult[void],
   tds: ThreadDatastorePtr,
   key: Key,
   data: seq[byte]
-) =
-  echoed "put request args: ", $getThreadId()
-  let bkey = KeyBuffer.new(key)
-  let bval = DataBuffer.new(data)
+): Future[?!void] =
 
-  echoed "spawn put request: ", $getThreadId()
-  tds[].tp.spawn putTask(ret, tds, bkey, bval)
+  echoed "put request args: ", $getThreadId()
+
+  var putRes = newFuture[?!void]("threadbackend.put(tds, key, data)")
+  let sigFut = SharedSignal.new()
+
+  sigFut.
+    then(proc (sig: SharedSignal) =
+      echoed "got tresFut"
+      let
+        ret = newSharedPtr(ThreadResult[void])
+        bkey = KeyBuffer.new(key)
+        bval = DataBuffer.new(data)
+
+      echoed "spawn put request: ", $getThreadId()
+      # this spawns the taskpool Task
+      # but we can't wait on it directly - we use wait(ret[].sig)
+      tds[].tp.spawn putTask(sig, ret, tds, bkey, bval)
+
+      wait(sig).
+        then(proc () =
+          var ret = ret
+          let val = ret.convert(void)
+          putRes.complete(val)
+        ).cancelled(proc() =
+          discard
+        ).catch(proc(e: ref CatchableError) =
+          doAssert false, "will not be triggered"
+        )
+  ).catch(proc(e: ref CatchableError) =
+    echoed "err tresFut"
+    var res: ?!void
+    res.err(e)
+    putRes.complete(res)
+  )
 
 
 proc deleteTask*(
diff --git a/results.rb b/results.rb
new file mode 100644
index 0000000..c8fe3e2
--- /dev/null
+++ b/results.rb
@@ -0,0 +1,112 @@
+[Suite] Share buffer test
+SharedPtr: alloc: 0x102508090 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025080f0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508150 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025081b0 tp: DataBufferHolder
+SharedPtr: destroy: 0x102498180"0x1025081b0" cnt: 0x102508190 tp: DataBufferHolder
+SharedPtr: decr: 0x1025081b0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102498330"0x102508150" cnt: 0x102508130 tp: DataBufferHolder
+SharedPtr: decr: 0x102508150 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024984e0"0x1025080f0" cnt: 0x1025080d0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025080f0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102498690"0x102508090" cnt: 0x102508070 tp: DataBufferHolder
+SharedPtr: decr: 0x102508090 -1 tp: DataBufferHolder
+  [OK] creation
+SharedPtr: alloc: 0x102508210 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508270 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025082d0 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249a990"0x1025082d0" cnt: 0x1025082b0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025082d0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249ab40"0x102508270" cnt: 0x102508250 tp: DataBufferHolder
+SharedPtr: decr: 0x102508270 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249acf0"0x102508210" cnt: 0x1025081f0 tp: DataBufferHolder
+SharedPtr: decr: 0x102508210 -1 tp: DataBufferHolder
+  [OK] equality
+SharedPtr: alloc: 0x102508330 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508390 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025083f0 tp: DataBufferHolder
+SharedPtr: destroy: 0x102498240"0x1025083f0" cnt: 0x1025083d0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025083f0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024983f0"0x102508390" cnt: 0x102508370 tp: DataBufferHolder
+SharedPtr: decr: 0x102508390 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024985a0"0x102508330" cnt: 0x102508310 tp: DataBufferHolder
+SharedPtr: decr: 0x102508330 -1 tp: DataBufferHolder
+  [OK] toString
+SharedPtr: alloc: 0x102508450 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025084b0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508510 tp: DataBufferHolder
+SharedPtr: destroy: 0x102493ab0"0x102508510" cnt: 0x1025084f0 tp: DataBufferHolder
+SharedPtr: decr: 0x102508510 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102493cc0"0x1025084b0" cnt: 0x102508490 tp: DataBufferHolder
+SharedPtr: decr: 0x1025084b0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102493e40"0x102508450" cnt: 0x102508430 tp: DataBufferHolder
+SharedPtr: decr: 0x102508450 -1 tp: DataBufferHolder
+  [OK] hash
+SharedPtr: alloc: 0x102508570 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025085d0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508630 tp: DataBufferHolder
+SharedPtr: destroy: 0x102499480"0x102508630" cnt: 0x102508610 tp: DataBufferHolder
+SharedPtr: decr: 0x102508630 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102499630"0x1025085d0" cnt: 0x1025085b0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025085d0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024997e0"0x102508570" cnt: 0x102508550 tp: DataBufferHolder
+SharedPtr: decr: 0x102508570 -1 tp: DataBufferHolder
+  [OK] hashes differ
+SharedPtr: alloc: 0x102508690 tp: DataBufferHolder
+SharedPtr: alloc: 0x1025086f0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508750 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249dd20"0x102508750" cnt: 0x102508730 tp: DataBufferHolder
+SharedPtr: decr: 0x102508750 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249df30"0x1025086f0" cnt: 0x1025086d0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025086f0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024931b0"0x102508690" cnt: 0x102508670 tp: DataBufferHolder
+SharedPtr: decr: 0x102508690 -1 tp: DataBufferHolder
+  [OK] key conversion
+SharedPtr: alloc: 0x1025087b0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508810 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508870 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024975d0"0x102508870" cnt: 0x102508850 tp: DataBufferHolder
+SharedPtr: decr: 0x102508870 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102497780"0x102508810" cnt: 0x1025087f0 tp: DataBufferHolder
+SharedPtr: decr: 0x102508810 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102497b70"0x1025087b0" cnt: 0x102508790 tp: DataBufferHolder
+SharedPtr: decr: 0x1025087b0 -1 tp: DataBufferHolder
+  [OK] seq conversion
+SharedPtr: alloc: 0x1025088d0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508930 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508990 tp: DataBufferHolder
+SharedPtr: destroy: 0x10249ff00"0x102508990" cnt: 0x102508970 tp: DataBufferHolder
+SharedPtr: decr: 0x102508990 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102498210"0x102508930" cnt: 0x102508910 tp: DataBufferHolder
+SharedPtr: decr: 0x102508930 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024981b0"0x1025088d0" cnt: 0x1025088b0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025088d0 -1 tp: DataBufferHolder
+  [OK] seq conversion
+SharedPtr: alloc: 0x1025089f0 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508a50 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508ab0 tp: DataBufferHolder
+running
+thread1
+thread2
+SharedPtr: alloc: 0x102508b30 tp: DataBufferHolder
+SharedPtr: alloc: 0x102508b90 tp: DataBufferHolder
+SharedPtr: destroy: 0x1025a0150"0x102508b30" cnt: 0x102508b10 tp: DataBufferHolder
+SharedPtr: decr: 0x102508b30 -1 tp: DataBufferHolder
+thread1: sending: (val: (buf: ..., size: 11))
+mybytes2: (val: (buf: ..., size: 11))
+thread1: sent, left over: (val: (buf: ..., size: 11))
+thread2: receiving 
+thread2: received: (val: (buf: ..., size: 11))
+SharedPtr: destroy: 0x102620120"0x102508b90" cnt: nil tp: DataBufferHolder
+SharedPtr: destroy: 0x1025a0450"0x102508b90" cnt: 0x102508b70 tp: DataBufferHolder
+SharedPtr: decr: 0x102508b90 1 tp: DataBufferHolder
+SharedPtr: destroy: 0x1025a0600"0x102508b90" cnt: 0x102508b10 tp: DataBufferHolder
+SharedPtr: decr: 0x102508b90 -2 tp: DataBufferHolder
+SharedPtr: destroy: 0x1024936f0"0x102508ab0" cnt: 0x102508a90 tp: DataBufferHolder
+SharedPtr: decr: 0x102508ab0 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102493cf0"0x102508a50" cnt: 0x102508a30 tp: DataBufferHolder
+SharedPtr: decr: 0x102508a50 -1 tp: DataBufferHolder
+SharedPtr: destroy: 0x102493960"0x1025089f0" cnt: 0x1025089d0 tp: DataBufferHolder
+SharedPtr: decr: 0x1025089f0 -1 tp: DataBufferHolder
+  [OK] basic thread test
+SharedPtr: destroy: 0x102493f00"0x102508b90" cnt: nil tp: DataBufferHolder
\ No newline at end of file