database: Return NULL when inserting a duplicate item

This provides us a more straightforward way to determine if the database
changed.

Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>

DESIGN

@@ -114,11 +114,9 @@ On-disk files:
 - File:
 	class File : public std::fstream {
 	private:
-			- Return false if the file has FILE_TYPE_LEGACY set
 		unsigned int version;
 		OpenMode mode;
 		FileLocHint hint;
-			- Return false if the file has FILE_TYPE_LEGACY set
 		string filepath;
 
 	public:
@@ -306,7 +304,7 @@ Database:
 	T *Database :: insert(const T &item);
 		Look up the item in the _keys map.
 		If we find an item with the same key:
-			- Return a pointer to the found item.
+			- Return NULL.
 		Otherwise:
 			- Use new to allocate memory for a new item.
 			- Add the new item to the end of the _db.
@@ -551,9 +549,6 @@ Tag Database:
 		Add a new track to the track_db and return a pointer to it.
 		Return NULL if this track is already in the database.
 
-		Check the database size both before and after to see if a new
-		track has been added.
-
 	Library *tagdb :: add_library(const std::string &filepath);
 		Add a new path to library_db.  Return a pointer to the new path
 		or return NULL if the path is already in the database.

include/database.hpp

@@ -85,7 +85,7 @@ T *Database<T> :: insert(const T &val)
 	T *t = find(val.primary_key());
 
 	if (t != NULL)
-		return t;
+		return NULL;
 
 	t = new T(val);
 	_db.push_back(t);

lib/tags.cpp

@@ -213,6 +213,15 @@ static inline const std::string format_tag(const TagLib::String &str)
 	return str.stripWhiteSpace().to8Bit(true);
 }
 
+template <class T>
+static T *find_or_insert(const T &tag, Database<T> &db)
+{
+	T *ret = db.find(tag.primary_key());
+	if (!ret)
+		ret = db.insert(tag);
+	return ret;
+}
+
 void Track :: tag()
 {
 	TagLib :: Tag *tag;
@@ -227,9 +236,9 @@ void Track :: tag()
 	tag   = ref.tag();
 	audio = ref.audioProperties();
 
-	artist = artist_db.insert(Artist(format_tag(tag->artist())));
+	artist = find_or_insert(Artist(format_tag(tag->artist())), artist_db);
-	album  = album_db.insert(Album(format_tag(tag->album()), tag->year()));
+	album  = find_or_insert(Album(format_tag(tag->album()), tag->year()), album_db);
-	genre  = genre_db.insert(Genre(format_tag(tag->genre())));
+	genre  = find_or_insert(Genre(format_tag(tag->genre())), genre_db);
 	track  = tag->track();
 	length = audio->length();
 	title  = format_tag(tag->title());
@@ -331,21 +340,15 @@ void tagdb :: commit_library()
 
 Track *tagdb :: add_track(const std::string &filepath, Library *library)
 {
-	unsigned int size = track_db.size();
 	Track *track = track_db.insert(Track(filepath, library));
-	if (size == track_db.size())
+	if (track)
-		return NULL;
+		track->tag();
-	track->tag();
 	return track;
 }
 
 Library *tagdb :: add_library(const std::string &filepath)
 {
-	unsigned int size = library_db.size();
+	return library_db.insert(Library(filepath));
-	Library *library = library_db.insert(Library(filepath));
-	if (size == library_db.size())
-		return NULL;
-	return library;
 }
 
 void tagdb :: remove_track(unsigned int track_id)

tests/src/database.cpp

@@ -119,11 +119,7 @@ int main(int argc, char **argv)
 	 */
 	for (unsigned int i = 0; i < n; i++) {
 		IntEntry *it = db.insert(IntEntry(i));
-		if (it->id != i)
+		if (it != NULL)
-			test_results(false, __LINE__);
-		if (i == 1 && it != one)
-			test_results(false, __LINE__);
-		if (i == 3 && it != three)
 			test_results(false, __LINE__);
 	}
 	test_results(true, __LINE__);
@@ -205,14 +201,14 @@ int main(int argc, char **argv)
 	 * 9. Test inserting once again
 	 */
 	for (unsigned int i = 0; i < n; i++) {
-		index = db.insert(IntEntry(i))->id;
+		IntEntry *it = db.insert(IntEntry(i));
 		if ((i % 2) == 0) {
 			size++;
 			actual++;
-			if (index != (n + (i / 2)))
+			if (it->id != (n + (i / 2)))
 				test_results(false, __LINE__);
 		} else {
-			if (index != i)
+			if (it != NULL)
 				test_results(false, __LINE__);
 		}
 	}

tests/src/tagdb.cpp

@@ -123,7 +123,7 @@ test_tracks:
 	tagdb :: remove_library(library->id);
 	test_track_size(0, __LINE__);
 
-
+	library = tagdb :: add_library("Music");
 	if (init_called == true)
 		tagdb :: commit();