Libraries: Move to Userland/Libraries/

1 files changed, 58 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGUI/UndoStack.h b/Userland/Libraries/LibGUI/UndoStack.h
new file mode 100644
index 0000000000..9c6d0504e1
--- /dev/null
+++ b/Userland/Libraries/LibGUI/UndoStack.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/NonnullOwnPtrVector.h>
+#include <LibGUI/Forward.h>
+
+namespace GUI {
+
+class UndoStack {
+public:
+    UndoStack();
+    ~UndoStack();
+
+    void push(NonnullOwnPtr<Command>&&);
+
+    bool can_undo() const { return m_stack_index < m_stack.size() && !m_stack.is_empty(); }
+    bool can_redo() const { return m_stack_index > 0 && !m_stack.is_empty(); }
+
+    void undo();
+    void redo();
+
+    void finalize_current_combo();
+
+private:
+    struct UndoCommandsContainer {
+        NonnullOwnPtrVector<Command> m_undo_vector;
+    };
+
+    NonnullOwnPtrVector<UndoCommandsContainer> m_stack;
+    size_t m_stack_index { 0 };
+};
+
+}