From 05f8515b0d0aa64c73477af1df721fb171e41b7d Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Wed, 17 Apr 2024 15:03:25 +0200
Subject: [PATCH] added 'activeProducer' feature

---
 malebolgia.nimble  | 10 +++++-----
 src/malebolgia.nim | 15 +++++++++++----
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/malebolgia.nimble b/malebolgia.nimble
index 0007967..97ded92 100644
--- a/malebolgia.nimble
+++ b/malebolgia.nimble
@@ -1,10 +1,10 @@
 # Package
 
-version       = "1.3.1"
-author        = "Araq"
-description   = "Malebolgia creates new spawns. Experiments with thread pools and related APIs."
-license       = "MIT"
-srcDir        = "src"
+version = "1.3.2"
+author = "Araq"
+description = "Malebolgia creates new spawns. Experiments with thread pools and related APIs."
+license = "MIT"
+srcDir = "src"
 
 
 # Dependencies
diff --git a/src/malebolgia.nim b/src/malebolgia.nim
index 273309c..c92e9f4 100644
--- a/src/malebolgia.nim
+++ b/src/malebolgia.nim
@@ -14,7 +14,7 @@ type
     runningTasks: int
     stopToken: Atomic[bool]
     shouldEndAt: Time
-    usesTimeout: bool
+    usesTimeout, activeProducer: bool
 
 proc `=destroy`(m: var Master) {.inline.} =
   deinitCond(m.c)
@@ -23,13 +23,17 @@ proc `=destroy`(m: var Master) {.inline.} =
 proc `=copy`(dest: var Master; src: Master) {.error.}
 proc `=sink`(dest: var Master; src: Master) {.error.}
 
-proc createMaster*(timeout = default(Duration)): Master =
+proc createMaster*(timeout = default(Duration); activeProducer = false): Master =
+  ## Set `activeProducer` to true to prevent the master thread from
+  ## running a task directly.
+  ## But beware! This can introduce deadlocks for recursive loads!
   result = default(Master)
   initCond(result.c)
   initLock(result.L)
   if timeout != default(Duration):
     result.usesTimeout = true
     result.shouldEndAt = getTime() + timeout
+  result.activeProducer = activeProducer
 
 proc cancel*(m: var Master) =
   ## Try to stop all running tasks immediately.
@@ -163,9 +167,12 @@ proc panicStop*() =
   deinitCond(chan.spaceAvailable)
   deinitLock(chan.L)
 
+proc shouldSend(master: var Master): bool {.inline.} =
+  master.activeProducer or busyThreads.load(moRelaxed) < ThreadPoolSize-1
+
 template spawnImplRes[T](master: var Master; fn: typed; res: T) =
   if stillHaveTime(master):
-    if busyThreads.load(moRelaxed) < ThreadPoolSize-1:
+    if shouldSend(master):
       taskCreated master
       send PoolTask(m: addr(master), t: toTask(fn), result: addr res)
     else:
@@ -173,7 +180,7 @@ template spawnImplRes[T](master: var Master; fn: typed; res: T) =
 
 template spawnImplNoRes(master: var Master; fn: typed) =
   if stillHaveTime(master):
-    if busyThreads.load(moRelaxed) < ThreadPoolSize-1:
+    if shouldSend(master):
       taskCreated master
       send PoolTask(m: addr(master), t: toTask(fn), result: nil)
     else: