Prepare loading the named column layouts from the settings.

src/library/trackmodel.h

@@ -191,15 +191,24 @@ class TrackModel {
     /*non-virtual*/ bool hasCapabilities(Capabilities caps) const {
         return (getCapabilities() & caps) == caps;
     }
+
+    /*non-virtual*/ QString getKeyForModelSetting(const QString& name) const {
+        if (name.startsWith("shared_settings.")) {
+            return "mixxx.db.model." + name;
+        } else {
+            return m_settingsNamespace + "." + name;
+        }
+    }
+
     virtual QString getModelSetting(const QString& name) {
         SettingsDAO settings(m_db);
-        QString key = m_settingsNamespace + "." + name;
+        QString key = getKeyForModelSetting(name);
         return settings.getValue(key);
     }
 
     virtual bool setModelSetting(const QString& name, const QVariant& value) {
         SettingsDAO settings(m_db);
-        QString key = m_settingsNamespace + "." + name;
+        QString key = getKeyForModelSetting(name);
         return settings.setValue(key, value);
     }
 

src/proto/headers.proto

@@ -23,3 +23,11 @@ message HeaderViewState {
   // This corresponds to the Qt::SortOrder enum.
   optional int32 sort_order = 4;
 }
+
+message NamedHeaderLayouts {
+  message NamedHeaderLayout {
+    required string layout_name = 1;
+    required HeaderViewState header_view_state = 2;
+  }
+  repeated NamedHeaderLayout layout = 1;
+}

src/widget/wtracktableviewheader.cpp

@@ -11,6 +11,28 @@
 
 #define WTTVH_MINIMUM_SECTION_SIZE 20
 
+NamedHeaderLayouts::NamedHeaderLayouts(const QString& base64serialized) {
+    // First decode the array from Base64, then initialize the protobuf from it.
+    QByteArray array = QByteArray::fromBase64(base64serialized.toLatin1());
+    if (!m_named_layouts.ParseFromArray(array.constData(), array.size())) {
+        qWarning() << "Could not parse m_named_layouts from QByteArray of size "
+                   << array.size();
+        return;
+    }
+}
+
+QString NamedHeaderLayouts::saveState() const {
+    // Serialize the proto to a byte array, then encode the array as Base64.
+#if GOOGLE_PROTOBUF_VERSION >= 3001000
+    int size = static_cast<int>(m_named_layouts.ByteSizeLong());
+#else
+    int size = m_named_layouts.ByteSize();
+#endif
+    QByteArray array(size, '\0');
+    m_named_layouts.SerializeToArray(array.data(), size);
+    return QString(array.toBase64());
+}
+
 HeaderViewState::HeaderViewState(const QHeaderView& headers) {
     QAbstractItemModel* model = headers.model();
     for (int vi = 0; vi < headers.count(); ++vi) {

src/widget/wtracktableviewheader.h

@@ -51,6 +51,23 @@ class HeaderViewState {
     mixxx::library::HeaderViewState m_view_state;
 };
 
+class NamedHeaderLayouts {
+public:
+    NamedHeaderLayouts() {}
+
+    // Populate from an existing protobuf, mostly for testing.
+    explicit NamedHeaderLayouts(const mixxx::library::NamedHeaderLayouts& pb)
+            : m_named_layouts(pb) { }
+
+    // Populate the object with the serialized protobuf data provided.
+    explicit NamedHeaderLayouts(const QString& base64serialized);
+
+    // Returns a serialized protobuf of the current state.
+    QString saveState() const;
+
+private:
+    mixxx::library::NamedHeaderLayouts m_named_layouts;
+};
 
 class WTrackTableViewHeader : public QHeaderView {
     Q_OBJECT