Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibGUI/GSortingProxyModel.cpp

@@ -0,0 +1,105 @@
+#include <AK/QuickSort.h>
+#include <LibGUI/GSortingProxyModel.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+GSortingProxyModel::GSortingProxyModel(NonnullRefPtr<GModel>&& target)
+    : m_target(move(target))
+    , m_key_column(-1)
+{
+    m_target->on_model_update = [this](GModel&) {
+        resort();
+    };
+}
+
+GSortingProxyModel::~GSortingProxyModel()
+{
+}
+
+int GSortingProxyModel::row_count(const GModelIndex& index) const
+{
+    return target().row_count(index);
+}
+
+int GSortingProxyModel::column_count(const GModelIndex& index) const
+{
+    return target().column_count(index);
+}
+
+GModelIndex GSortingProxyModel::map_to_target(const GModelIndex& index) const
+{
+    if (!index.is_valid())
+        return {};
+    if (index.row() >= m_row_mappings.size() || index.column() >= column_count())
+        return {};
+    return target().index(m_row_mappings[index.row()], index.column());
+}
+
+String GSortingProxyModel::row_name(int index) const
+{
+    return target().row_name(index);
+}
+
+String GSortingProxyModel::column_name(int index) const
+{
+    return target().column_name(index);
+}
+
+GModel::ColumnMetadata GSortingProxyModel::column_metadata(int index) const
+{
+    return target().column_metadata(index);
+}
+
+GVariant GSortingProxyModel::data(const GModelIndex& index, Role role) const
+{
+    return target().data(map_to_target(index), role);
+}
+
+void GSortingProxyModel::update()
+{
+    target().update();
+}
+
+void GSortingProxyModel::set_key_column_and_sort_order(int column, GSortOrder sort_order)
+{
+    if (column == m_key_column && sort_order == m_sort_order)
+        return;
+
+    ASSERT(column >= 0 && column < column_count());
+    m_key_column = column;
+    m_sort_order = sort_order;
+    resort();
+}
+
+void GSortingProxyModel::resort()
+{
+    int previously_selected_target_row = map_to_target(selected_index()).row();
+    int row_count = target().row_count();
+    m_row_mappings.resize(row_count);
+    for (int i = 0; i < row_count; ++i)
+        m_row_mappings[i] = i;
+    if (m_key_column == -1) {
+        did_update();
+        return;
+    }
+    quick_sort(m_row_mappings.begin(), m_row_mappings.end(), [&](auto row1, auto row2) -> bool {
+        auto data1 = target().data(target().index(row1, m_key_column), GModel::Role::Sort);
+        auto data2 = target().data(target().index(row2, m_key_column), GModel::Role::Sort);
+        if (data1 == data2)
+            return 0;
+        bool is_less_than = data1 < data2;
+        return m_sort_order == GSortOrder::Ascending ? is_less_than : !is_less_than;
+    });
+    if (previously_selected_target_row != -1) {
+        // Preserve selection.
+        ASSERT(m_row_mappings.size() == row_count);
+        for (int i = 0; i < row_count; ++i) {
+            if (m_row_mappings[i] == previously_selected_target_row) {
+                set_selected_index(index(i, 0));
+                break;
+            }
+        }
+    }
+
+    did_update();
+}