db/upnp/Object: use strictly-typed enums

At the same time, rename the enum types and the class attributes, and
add an "UNKNOWN" type/class.  The latter avoids the "-1" hack.

src/db/upnp/Directory.cxx

@@ -56,9 +56,9 @@ public:
 		:m_dir(dir)
 	{
 		m_okitems["object.item.audioItem.musicTrack"] =
-			UPnPDirObject::audioItem_musicTrack;
+			UPnPDirObject::ItemClass::MUSIC;
 		m_okitems["object.item.playlistItem"] =
-			UPnPDirObject::audioItem_playlist;
+			UPnPDirObject::ItemClass::PLAYLIST;
 	}
 	UPnPDirContent& m_dir;
 
@@ -74,7 +74,7 @@ protected:
 		case 'c':
 			if (!strcmp(name, "container")) {
 				m_tobj.clear();
-				m_tobj.m_type = UPnPDirObject::container;
+				m_tobj.type = UPnPDirObject::Type::CONTAINER;
 				m_tobj.m_id = m_path.back().attributes["id"];
 				m_tobj.m_pid = m_path.back().attributes["parentID"];
 			}
@@ -82,7 +82,7 @@ protected:
 		case 'i':
 			if (!strcmp(name, "item")) {
 				m_tobj.clear();
-				m_tobj.m_type = UPnPDirObject::item;
+				m_tobj.type = UPnPDirObject::Type::ITEM;
 				m_tobj.m_id = m_path.back().attributes["id"];
 				m_tobj.m_pid = m_path.back().attributes["parentID"];
 			}
@@ -96,14 +96,14 @@ protected:
 		bool ok =  !m_tobj.m_id.empty() && !m_tobj.m_pid.empty() &&
 			!m_tobj.m_title.empty();
 
-		if (ok && m_tobj.m_type == UPnPDirObject::item) {
+		if (ok && m_tobj.type == UPnPDirObject::Type::ITEM) {
 			auto it = m_okitems.find(m_tobj.m_props["upnp:class"]);
 			if (it == m_okitems.end()) {
 				PLOGINF("checkobjok: found object of unknown class: [%s]\n",
 					m_tobj.m_props["upnp:class"].c_str());
 				ok = false;
 			} else {
-				m_tobj.m_iclass = it->second;
+				m_tobj.item_class = it->second;
 			}
 		}
 

src/db/upnp/Object.hxx

@@ -30,7 +30,12 @@
  */
 class UPnPDirObject {
 public:
-	enum ObjType {item, container};
+	enum class Type {
+		UNKNOWN,
+		ITEM,
+		CONTAINER,
+	};
+
 	// There are actually several kinds of containers:
 	// object.container.storageFolder, object.container.person,
 	// object.container.playlistContainer etc., but they all seem to
@@ -38,13 +43,17 @@ public:
 	// items are special to us, and so should playlists, but I've not
 	// seen one of the latter yet (servers seem to use containers for
 	// playlists).
-	enum ItemClass {audioItem_musicTrack, audioItem_playlist};
+	enum class ItemClass {
+		UNKNOWN,
+		MUSIC,
+		PLAYLIST,
+	};
 
 	std::string m_id; // ObjectId
 	std::string m_pid; // Parent ObjectId
 	std::string m_title; // dc:title. Directory name for a container.
-	ObjType m_type; // item or container
-	ItemClass m_iclass;
+	Type type;
+	ItemClass item_class;
 	// Properties as gathered from the XML document (url, artist, etc.)
 	// The map keys are the XML tag or attribute names.
 	std::map<std::string, std::string> m_props;
@@ -68,8 +77,8 @@ public:
 		m_id.clear();
 		m_pid.clear();
 		m_title.clear();
-		m_type = (ObjType)-1;
-		m_iclass = (ItemClass)-1;
+		type = Type::UNKNOWN;
+		item_class = ItemClass::UNKNOWN;
 		m_props.clear();
 	}
 };