From d10db3fddd76e79b85c065b2b77e7bb3742114c0 Mon Sep 17 00:00:00 2001
From: Relintai <relintai@protonmail.com>
Date: Sat, 10 Sep 2022 03:07:49 +0200
Subject: [PATCH] Now ThreadPool uses a List internally as a queue inetad of a
 Vector.

---
 modules/thread_pool/thread_pool.cpp | 91 ++++++-----------------------
 modules/thread_pool/thread_pool.h   | 11 +---
 2 files changed, 20 insertions(+), 82 deletions(-)

diff --git a/modules/thread_pool/thread_pool.cpp b/modules/thread_pool/thread_pool.cpp
index e372cdeb6..c68621ece 100644
--- a/modules/thread_pool/thread_pool.cpp
+++ b/modules/thread_pool/thread_pool.cpp
@@ -82,17 +82,11 @@ bool ThreadPool::has_job(const Ref<ThreadPoolJob> &job) {
 
 	_THREAD_SAFE_LOCK_
 
-	for (int i = _current_queue_head; i < _current_queue_tail; ++i) {
-		if (_queue[i] == job) {
-			_THREAD_SAFE_UNLOCK_
-
-			return true;
-		}
-	}
+	List<Ref<ThreadPoolJob>>::Element *E = _queue.find(job);
 
 	_THREAD_SAFE_UNLOCK_
 
-	return false;
+	return E;
 }
 
 void ThreadPool::add_job(const Ref<ThreadPoolJob> &job) {
@@ -111,22 +105,7 @@ void ThreadPool::add_job(const Ref<ThreadPoolJob> &job) {
 		}
 	}
 
-	if (_current_queue_tail == _queue.size()) {
-		if (_current_queue_head == 0) {
-			_queue.resize(_queue.size() + _queue_grow_size);
-		} else {
-			int j = 0;
-
-			for (int i = _current_queue_head; i < _current_queue_tail; ++i) {
-				_queue.write[j++] = _queue[i];
-			}
-
-			_current_queue_head = 0;
-			_current_queue_tail = j;
-		}
-	}
-
-	_queue.write[_current_queue_tail++] = job;
+	_queue.push_back(job);
 
 	_THREAD_SAFE_UNLOCK_
 }
@@ -138,23 +117,7 @@ void ThreadPool::cancel_job(Ref<ThreadPoolJob> job) {
 
 	_THREAD_SAFE_LOCK_
 
-	//it it's in the queue remove it
-	for (int i = _current_queue_head; i < _current_queue_tail; ++i) {
-		Ref<ThreadPoolJob> cjob = _queue[i];
-
-		if (cjob == job) {
-			_queue.write[i].unref();
-
-			for (int j = i; j + 1 < _current_queue_tail; ++j) {
-				_queue.write[j] = _queue[j + 1];
-			}
-
-			--_current_queue_tail;
-
-			_THREAD_SAFE_UNLOCK_
-			return;
-		}
-	}
+	_queue.erase(job);
 
 	_THREAD_SAFE_UNLOCK_
 }
@@ -166,14 +129,9 @@ void ThreadPool::cancel_job_wait(Ref<ThreadPoolJob> job) {
 
 	_THREAD_SAFE_LOCK_
 
-	for (int i = _current_queue_head; i < _current_queue_tail; ++i) {
-		Ref<ThreadPoolJob> j = _queue[i];
-
-		if (j == job) {
-			_queue.write[i].unref();
-			_THREAD_SAFE_UNLOCK_
-			return;
-		}
+	if (_queue.erase(job)) {
+		_THREAD_SAFE_UNLOCK_
+		return;
 	}
 
 	_THREAD_SAFE_UNLOCK_
@@ -197,19 +155,13 @@ void ThreadPool::_thread_finished(ThreadPoolContext *context) {
 
 	context->job.unref();
 
-	while (_current_queue_head != _current_queue_tail) {
-		context->job = _queue.get(_current_queue_head);
-
-		if (!context->job.is_valid()) {
-			++_current_queue_head;
-			continue;
-		}
+	while (_queue.size() > 0 && !context->job.is_valid()) {
+		context->job = _queue.front()->get();
+		_queue.pop_front();
+	}
 
+	if (context->job.is_valid()) {
 		context->semaphore->post();
-		_queue.write[_current_queue_head].unref();
-
-		++_current_queue_head;
-		break;
 	}
 
 	_THREAD_SAFE_UNLOCK_
@@ -242,16 +194,17 @@ void ThreadPool::register_update() {
 }
 
 void ThreadPool::update() {
-	if (_current_queue_head == _current_queue_tail)
+	if (_queue.size() == 0) {
 		return;
+	}
 
 	float remaining_time = _max_time_per_frame;
 
-	while (remaining_time > 0 && _current_queue_head != _current_queue_tail) {
-		Ref<ThreadPoolJob> job = _queue.get(_current_queue_head);
+	while (remaining_time > 0 && _queue.size() > 0) {
+		Ref<ThreadPoolJob> job = _queue.front()->get();
 
 		if (!job.is_valid()) {
-			++_current_queue_head;
+			_queue.pop_front();
 			continue;
 		}
 
@@ -261,7 +214,7 @@ void ThreadPool::update() {
 		remaining_time -= job->get_current_execution_time();
 
 		if (job->get_complete() || job->get_cancelled()) {
-			_queue.write[_current_queue_head++].unref();
+			_queue.pop_front();
 		}
 	}
 }
@@ -269,9 +222,6 @@ void ThreadPool::update() {
 ThreadPool::ThreadPool() {
 	_instance = this;
 
-	_current_queue_head = 0;
-	_current_queue_tail = 0;
-
 	_use_threads = GLOBAL_DEF("thread_pool/use_threads", true);
 	_thread_count = GLOBAL_DEF("thread_pool/thread_count", -1);
 	_thread_fallback_count = GLOBAL_DEF("thread_pool/thread_fallback_count", 4);
@@ -285,10 +235,6 @@ ThreadPool::ThreadPool() {
 	//Todo Add help text, as this will only come into play if threading is disabled, or not available
 	_max_work_per_frame_percent = GLOBAL_DEF("thread_pool/max_work_per_frame_percent", 25);
 
-	_queue_start_size = GLOBAL_DEF("thread_pool/queue_start_size", 20);
-	_queue_grow_size = GLOBAL_DEF("thread_pool/queue_grow_size", 10);
-	_queue.resize(_queue_start_size);
-
 	//Todo this should be recalculated constantly to smooth out performance better
 	_max_time_per_frame = (1 / 60.0) * (_max_work_per_frame_percent / 100.0);
 
@@ -346,7 +292,6 @@ ThreadPool::~ThreadPool() {
 	_threads.clear();
 
 	_queue.clear();
-	//_job_pool.clear();
 }
 
 void ThreadPool::_bind_methods() {
diff --git a/modules/thread_pool/thread_pool.h b/modules/thread_pool/thread_pool.h
index 9c649e6e6..d957a622d 100644
--- a/modules/thread_pool/thread_pool.h
+++ b/modules/thread_pool/thread_pool.h
@@ -27,6 +27,7 @@ SOFTWARE.
 
 #include "core/object/object.h"
 #include "core/containers/vector.h"
+#include "core/containers/list.h"
 
 #include "core/os/semaphore.h"
 #include "core/os/thread.h"
@@ -100,15 +101,7 @@ private:
 
 	Vector<ThreadPoolContext *> _threads;
 
-	Vector<Ref<ThreadPoolJob>> _queue;
-	int _current_queue_head;
-	int _current_queue_tail;
-
-	int _queue_start_size;
-	int _queue_grow_size;
-
-	//todo
-	//Vector<Ref<ThreadPoolJob> > _job_pool;
+	List<Ref<ThreadPoolJob>> _queue;
 };
 
 #endif