From cfd21f8ca2c0a8135dea6bb8dbcf38ebbe0903b4 Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Fri, 2 Jun 2023 22:34:02 +0200
Subject: [PATCH] Windows thread pool.

---
 src/utils/taskqueue.c | 52 ++++++++++++++++++++++++++++++++++++++++++-
 src/version.h         |  2 +-
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/src/utils/taskqueue.c b/src/utils/taskqueue.c
index e2e1ce75e..1100bedaa 100644
--- a/src/utils/taskqueue.c
+++ b/src/utils/taskqueue.c
@@ -51,8 +51,58 @@ void taskqueue_run(int threads, Task **task_list)
 	pthread_mutex_destroy(&queue.lock);
 }
 
-#else
+#elif PLATFORM_WINDOWS
 
+#include <Windows.h>
+#include <process.h>
+
+typedef struct TaskQueue_
+{
+	CRITICAL_SECTION lock;
+	Task **queue;
+} TaskQueue;
+
+static DWORD WINAPI taskqueue_thread(LPVOID lpParam)
+{
+	TaskQueue *task_queue = (TaskQueue *)lpParam;
+	bool is_active = false;
+	while (1)
+	{
+		EnterCriticalSection(&task_queue->lock);
+		unsigned task_count = vec_size(task_queue->queue);
+		if (!task_count) goto SHUTDOWN;
+		Task *task = (Task*)task_queue->queue[task_count - 1];
+		vec_pop(task_queue->queue);
+		LeaveCriticalSection(&task_queue->lock);
+		task->task(task->arg);
+	}
+SHUTDOWN:
+	LeaveCriticalSection(&task_queue->lock);
+	return 0;
+}
+
+void taskqueue_run(int threads, Task **task_list)
+{
+	assert(threads > 0);
+	HANDLE *handles = malloc(sizeof(HANDLE) * (unsigned)threads);
+	TaskQueue queue = { .queue = task_list };
+	InitializeCriticalSection(&queue.lock);
+	for (int i = 0; i < threads; i++)
+	{
+		handles[i] = (HANDLE)_beginthreadex(NULL, 0, taskqueue_thread, &queue, 0, NULL);
+		if (handles[i] == NULL) error_exit("Fail to set up thread pool");
+	}
+	WaitForMultipleObjects(threads, handles, TRUE, INFINITE);
+
+	for (int i = 0; i < threads; i++)
+	{
+		CloseHandle(handles[i]);
+	}
+	free((void*)handles);
+	DeleteCriticalSection(&queue.lock);
+}
+
+#else
 
 void taskqueue_run(int threads, Task **task_list)
 {
diff --git a/src/version.h b/src/version.h
index 8cce8d362..1f910107e 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1 +1 @@
-#define COMPILER_VERSION "0.4.521"
\ No newline at end of file
+#define COMPILER_VERSION "0.4.522"
\ No newline at end of file