Thread pool implementation in GDScript for running multiple tasks in parallel. Unlike other implementations I have encountered this doesn't leak memory when the pool is unused and threads are joined eventually after the ThreadPool instance is freed from memory.

Constructing a ThreadPool instance takes two optional arguments:

• min_threads for the minimum number of threads to start with. [optional]
• max_threads for a maximum of threads to allocate when needed. [optional]

Sending a task to the thread pool is fairly easy via the submit_task method, which takes 2 arguments:

• function a FuncRef.
• arguments an array of arguments to pass to function. [optional]

The task will then be pushed into a queue until a thread claims it and executes it.

sumbit_task is a coroutine, you can use yield() to wait for task completion or retrieving the return value.

# Instantiate a thread pool
# with a minimum of 5 threads and maximum of 10
var thread_pool: = ThreadPool.new(5, 10)

func example() -> void:
	# queue a task to run inside a thread
	thread_pool.submit_task(funcref(self, "some_task1"))

	# wait for the task to finish
	var state = thread_pool.submit_task(funcref(self, "some_task2"), [2, 5])
	var result: int = yield(state, "completed")

	assert(result == 7)

func some_task1() -> void:
	# some processing ...
	pass

func some_task2(a: int, b: int) -> int:
	return a + b