Kernel: Move all tasks-related code to the Tasks subdirectory

Kernel/Tasks/WaitQueue.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Atomic.h>
+#include <Kernel/Locking/Spinlock.h>
+#include <Kernel/Tasks/Thread.h>
+
+namespace Kernel {
+
+class WaitQueue final : public Thread::BlockerSet {
+public:
+    u32 wake_one();
+    u32 wake_n(u32 wake_count);
+    u32 wake_all();
+
+    template<class... Args>
+    Thread::BlockResult wait_on(Thread::BlockTimeout const& timeout, Args&&... args)
+    {
+        return Thread::current()->block<Thread::WaitQueueBlocker>(timeout, *this, forward<Args>(args)...);
+    }
+
+    template<class... Args>
+    void wait_forever(Args&&... args)
+    {
+        (void)Thread::current()->block<Thread::WaitQueueBlocker>({}, *this, forward<Args>(args)...);
+    }
+
+protected:
+    virtual bool should_add_blocker(Thread::Blocker& b, void*) override;
+
+private:
+    bool m_wake_requested { false };
+};
+
+}