LibGUI: Add a MultiView widget, based on FileManager's "DirectoryView"

A MultiView is a combination of ItemView, TableView and ColumnsView
smashed into a single widget. You can switch between the view modes
by calling MultiView::set_view_mode().

Note that MultiView inherits from StackWidget, not AbstractView.
That's purely for practical reasons, although I'm not entirely sure
if there would be some benefit to having it inherit from AbstractView.

Libraries/LibGUI/Forward.h

@@ -53,6 +53,7 @@ class Model;
 class ModelEditingDelegate;
 class ModelIndex;
 class MouseEvent;
+class MultiView;
 class PaintEvent;
 class Painter;
 class ResizeCorner;

Libraries/LibGUI/Makefile

@@ -40,6 +40,7 @@ OBJS = \
     Model.o \
     ModelIndex.o \
     ModelSelection.o \
+    MultiView.o \
     Notification.o \
     Painter.o \
     ProgressBar.o \

Libraries/LibGUI/MultiView.cpp

@@ -0,0 +1,179 @@
+/*
+ * 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.
+ */
+
+#include <AK/FileSystemPath.h>
+#include <AK/StringBuilder.h>
+#include <LibGUI/Action.h>
+#include <LibGUI/ActionGroup.h>
+#include <LibGUI/Model.h>
+#include <LibGUI/MultiView.h>
+#include <LibGUI/Window.h>
+#include <stdio.h>
+#include <unistd.h>
+
+namespace GUI {
+
+MultiView::MultiView()
+{
+    set_active_widget(nullptr);
+    m_item_view = add<ItemView>();
+    m_columns_view = add<ColumnsView>();
+    m_table_view = add<TableView>();
+
+    m_item_view->on_activation = [&](auto& index) {
+        if (on_activation)
+            on_activation(index);
+    };
+    m_columns_view->on_activation = [&](auto& index) {
+        if (on_activation)
+            on_activation(index);
+    };
+    m_table_view->on_activation = [&](auto& index) {
+        if (on_activation)
+            on_activation(index);
+    };
+
+    m_table_view->on_selection_change = [this] {
+        if (on_selection_change)
+            on_selection_change();
+    };
+    m_item_view->on_selection_change = [this] {
+        if (on_selection_change)
+            on_selection_change();
+    };
+    m_columns_view->on_selection_change = [this] {
+        if (on_selection_change)
+            on_selection_change();
+    };
+
+    m_table_view->on_context_menu_request = [this](auto& index, auto& event) {
+        if (on_context_menu_request)
+            on_context_menu_request(index, event);
+    };
+    m_item_view->on_context_menu_request = [this](auto& index, auto& event) {
+        if (on_context_menu_request)
+            on_context_menu_request(index, event);
+    };
+    m_columns_view->on_context_menu_request = [this](auto& index, auto& event) {
+        if (on_context_menu_request)
+            on_context_menu_request(index, event);
+    };
+
+    m_table_view->on_drop = [this](auto& index, auto& event) {
+        if (on_drop)
+            on_drop(index, event);
+    };
+    m_item_view->on_drop = [this](auto& index, auto& event) {
+        if (on_drop)
+            on_drop(index, event);
+    };
+    m_columns_view->on_drop = [this](auto& index, auto& event) {
+        if (on_drop)
+            on_drop(index, event);
+    };
+
+    set_view_mode(ViewMode::Icon);
+
+    build_actions();
+}
+
+MultiView::~MultiView()
+{
+}
+
+void MultiView::set_view_mode(ViewMode mode)
+{
+    if (m_view_mode == mode)
+        return;
+    m_view_mode = mode;
+    update();
+    if (mode == ViewMode::List) {
+        set_active_widget(m_table_view);
+        return;
+    }
+    if (mode == ViewMode::Columns) {
+        set_active_widget(m_columns_view);
+        return;
+    }
+    if (mode == ViewMode::Icon) {
+        set_active_widget(m_item_view);
+        return;
+    }
+    ASSERT_NOT_REACHED();
+}
+
+void MultiView::set_model(RefPtr<Model> model)
+{
+    if (m_model == model)
+        return;
+    m_model = model;
+    for_each_view_implementation([&](auto& view) {
+        view.set_model(model);
+    });
+}
+
+void MultiView::set_model_column(int column)
+{
+    m_item_view->set_model_column(column);
+    m_columns_view->set_model_column(column);
+}
+
+void MultiView::set_column_hidden(int column_index, bool hidden)
+{
+    m_table_view->set_column_hidden(column_index, hidden);
+}
+
+void MultiView::build_actions()
+{
+    m_view_as_table_action = Action::create(
+        "Table view", Gfx::Bitmap::load_from_file("/res/icons/16x16/table-view.png"), [this](auto&) {
+            set_view_mode(ViewMode::List);
+            m_view_as_table_action->set_checked(true);
+        });
+    m_view_as_table_action->set_checkable(true);
+
+    m_view_as_icons_action = Action::create(
+        "Icon view", Gfx::Bitmap::load_from_file("/res/icons/16x16/icon-view.png"), [this](auto&) {
+            set_view_mode(ViewMode::Icon);
+            m_view_as_icons_action->set_checked(true);
+        });
+    m_view_as_icons_action->set_checkable(true);
+
+    m_view_as_columns_action = Action::create(
+        "Columns view", Gfx::Bitmap::load_from_file("/res/icons/16x16/columns-view.png"), [this](auto&) {
+            set_view_mode(ViewMode::Columns);
+            m_view_as_columns_action->set_checked(true);
+        });
+    m_view_as_columns_action->set_checkable(true);
+
+    m_view_type_action_group = make<ActionGroup>();
+    m_view_type_action_group->set_exclusive(true);
+    m_view_type_action_group->add_action(*m_view_as_table_action);
+    m_view_type_action_group->add_action(*m_view_as_icons_action);
+    m_view_type_action_group->add_action(*m_view_as_columns_action);
+}
+
+}

Libraries/LibGUI/MultiView.h

@@ -0,0 +1,118 @@
+/*
+ * 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 <LibGUI/Action.h>
+#include <LibGUI/ColumnsView.h>
+#include <LibGUI/ItemView.h>
+#include <LibGUI/StackWidget.h>
+#include <LibGUI/TableView.h>
+
+namespace GUI {
+
+class MultiView final : public GUI::StackWidget {
+    C_OBJECT(MultiView)
+public:
+    virtual ~MultiView() override;
+
+    void refresh();
+
+    Function<void()> on_selection_change;
+    Function<void(const ModelIndex&)> on_activation;
+    Function<void(const ModelIndex&)> on_selection;
+    Function<void(const ModelIndex&, const ContextMenuEvent&)> on_context_menu_request;
+    Function<void(const ModelIndex&, const DropEvent&)> on_drop;
+
+    enum ViewMode {
+        List,
+        Columns,
+        Icon
+    };
+    void set_view_mode(ViewMode);
+    ViewMode view_mode() const { return m_view_mode; }
+
+    int model_column() const { return m_model_column; }
+    void set_model_column(int);
+
+    void set_column_hidden(int column_index, bool hidden);
+
+    GUI::AbstractView& current_view()
+    {
+        switch (m_view_mode) {
+        case ViewMode::List:
+            return *m_table_view;
+        case ViewMode::Columns:
+            return *m_columns_view;
+        case ViewMode::Icon:
+            return *m_item_view;
+        default:
+            ASSERT_NOT_REACHED();
+        }
+    }
+
+    const ModelSelection& selection() const { return const_cast<MultiView&>(*this).current_view().selection(); }
+    ModelSelection& selection() { return current_view().selection(); }
+
+    template<typename Callback>
+    void for_each_view_implementation(Callback callback)
+    {
+        callback(*m_table_view);
+        callback(*m_item_view);
+        callback(*m_columns_view);
+    }
+
+    Model* model() { return m_model; }
+    const Model* model() const { return m_model; }
+
+    void set_model(RefPtr<Model>);
+
+    Action& view_as_table_action() { return *m_view_as_table_action; }
+    Action& view_as_icons_action() { return *m_view_as_icons_action; }
+    Action& view_as_columns_action() { return *m_view_as_columns_action; }
+
+private:
+    MultiView();
+
+    void build_actions();
+
+    ViewMode m_view_mode { Icon };
+    int m_model_column { 0 };
+
+    RefPtr<Model> m_model;
+
+    RefPtr<TableView> m_table_view;
+    RefPtr<ItemView> m_item_view;
+    RefPtr<ColumnsView> m_columns_view;
+
+    RefPtr<Action> m_view_as_table_action;
+    RefPtr<Action> m_view_as_icons_action;
+    RefPtr<Action> m_view_as_columns_action;
+
+    OwnPtr<ActionGroup> m_view_type_action_group;
+};
+
+}