From a54fa6b7de157a7962b29f02086da34d236a063f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=B6nke=20Ludwig?= <sludwig@rejectedsoftware.com>
Date: Wed, 23 Jan 2019 13:50:43 +0100
Subject: [PATCH] Implement runWorkerTaskDistH.

Variant of runWorkerTask that allows to get the handles of the created tasks.
---
 source/vibe/core/core.d     | 15 +++++++++++++++
 source/vibe/core/taskpool.d | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/source/vibe/core/core.d b/source/vibe/core/core.d
index 554a6a6..a11eded 100644
--- a/source/vibe/core/core.d
+++ b/source/vibe/core/core.d
@@ -586,6 +586,21 @@ void runWorkerTaskDist(alias method, T, ARGS...)(shared(T) object, ARGS args)
 }
 
 
+/** Runs a new asynchronous task in all worker threads and returns the handles.
+
+	`on_handle` is a callble that takes a `Task` as its only argument and is
+	called for every task instance that gets created.
+
+	See_also: `runWorkerTaskDist`
+*/
+void runWorkerTaskDistH(HCB, FT, ARGS...)(scope HCB on_handle, FT func, auto ref ARGS args)
+	if (is(typeof(*func) == function))
+{
+	setupWorkerThreads();
+	st_workerPool.runTaskDistH(on_handle, func, args);
+}
+
+
 /**
 	Sets up num worker threads.
 
diff --git a/source/vibe/core/taskpool.d b/source/vibe/core/taskpool.d
index 6d85596..d26d93c 100644
--- a/source/vibe/core/taskpool.d
+++ b/source/vibe/core/taskpool.d
@@ -176,7 +176,7 @@ shared final class TaskPool {
 		arguments are allowed to be able to guarantee thread-safety.
 
 		The number of tasks started is guaranteed to be equal to
-		`workerThreadCount`.
+		`threadCount`.
 	*/
 	void runTaskDist(FT, ARGS...)(FT func, auto ref ARGS args)
 		if (is(typeof(*func) == function))
@@ -193,6 +193,36 @@ shared final class TaskPool {
 		runTaskDist_unsafe(func, args);
 	}
 
+	/** Runs a new asynchronous task in all worker threads and returns the handles.
+
+		`on_handle` is an alias to a callble that takes a `Task` as its only
+		argument and is called for every task instance that gets created.
+
+		See_also: `runTaskDist`
+	*/
+	void runTaskDistH(HCB, FT, ARGS...)(scope HCB on_handle, FT func, auto ref ARGS args)
+	{
+		// TODO: support non-copyable argument types using .move
+		import std.concurrency : send, receiveOnly;
+
+		auto caller = Task.getThis();
+
+		// workaround to work when called outside of a task
+		if (caller == Task.init) {
+			.runTask({ runTaskDistH(on_handle, func, args); }).join();
+			return;
+		}
+
+		static void call(Task t, FT func, ARGS args) {
+			t.tid.send(Task.getThis());
+			func(args);
+		}
+		runTaskDist(&call, caller, func, args);
+
+		foreach (i; 0 .. this.threadCount)
+			on_handle(receiveOnly!Task);
+	}
+
 	private void runTaskHWrapper(FT, ARGS...)(Task* ret, FT func, ARGS args)
 	{
 		*ret = runTaskH!(FT, ARGS)(func, args);