Everywhere: Hoist the Libraries folder to the top-level

Author: https://github.com/trflynn89
Commit: 93712b24bf
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2256
Reviewed-by: https://github.com/sideshowbarker

Libraries/LibLine/KeyCallbackMachine.h

@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/HashMap.h>
+#include <AK/Vector.h>
+
+namespace Line {
+
+class Editor;
+
+struct Key {
+    enum Modifier : int {
+        None = 0,
+        Alt = 1,
+    };
+
+    int modifiers { None };
+    unsigned key { 0 };
+
+    Key(unsigned c)
+        : modifiers(None)
+        , key(c) {};
+
+    Key(unsigned c, int modifiers)
+        : modifiers(modifiers)
+        , key(c)
+    {
+    }
+
+    bool operator==(Key const& other) const
+    {
+        return other.key == key && other.modifiers == modifiers;
+    }
+};
+
+struct KeyCallback {
+    KeyCallback(Function<bool(Editor&)> cb)
+        : callback(move(cb))
+    {
+    }
+    Function<bool(Editor&)> callback;
+};
+
+class KeyCallbackMachine {
+public:
+    void register_key_input_callback(Vector<Key>, Function<bool(Editor&)> callback);
+    void key_pressed(Editor&, Key);
+    void interrupted(Editor&);
+    bool should_process_last_pressed_key() const { return m_should_process_this_key; }
+
+private:
+    HashMap<Vector<Key>, NonnullOwnPtr<KeyCallback>> m_key_callbacks;
+    Vector<Vector<Key>> m_current_matching_keys;
+    size_t m_sequence_length { 0 };
+    bool m_should_process_this_key { true };
+};
+
+}
+
+namespace AK {
+
+template<>
+struct Traits<Line::Key> : public DefaultTraits<Line::Key> {
+    static constexpr bool is_trivial() { return true; }
+    static unsigned hash(Line::Key k) { return pair_int_hash(k.key, k.modifiers); }
+};
+
+template<>
+struct Traits<Vector<Line::Key>> : public DefaultTraits<Vector<Line::Key>> {
+    static constexpr bool is_trivial() { return false; }
+    static unsigned hash(Vector<Line::Key> const& ks)
+    {
+        unsigned h = 0;
+        for (auto& k : ks)
+            h ^= Traits<Line::Key>::hash(k);
+        return h;
+    }
+};
+
+}