Do not re-create MLMediaLibrary instance when re-populating parser (S…

…hould fix issue karelia#60)

IMBAppleMediaLibraryParser.h

@@ -101,6 +101,13 @@
 
 @property (strong) id<IMBAppleMediaLibraryParserDelegate> configuration;
 
+/**
+ Initializes Apple media library and media source for the receiver.
+ @discussion
+ Must be called in the initialization process of the receiver but must not be called before configuration of receiver is set.
+ */
+- (instancetype)initializeMediaLibrary;
+
 /**
  Converts from IMB media type to Apple Media Library media type.
  */

IMBAppleMediaLibraryParser.m

@@ -76,6 +76,9 @@ - (NSString *)mediaType
 }
 
 /**
+ Initializes Apple media library and media source for the receiver.
+ @discussion
+ Must be called in the initialization process of the receiver but must not be called before configuration of receiver is set.
  */
 - (instancetype)initializeMediaLibrary
 {
@@ -96,9 +99,6 @@ - (IMBNode *)unpopulatedTopLevelNode:(NSError **)outError
     START_MEASURE(1);
     NSError *error = nil;
 
-    // (Re-)instantiate media library and media source (in Apple speak), because content might have changed on disk. Note though that this yet doesn't seem to have an effect when media library changes (Apple doesn't seem to update its object cache).
-    [self initializeMediaLibrary];
-
     MLMediaGroup *rootMediaGroup = [IMBAppleMediaLibraryPropertySynchronizer rootMediaGroupForMediaSource:self.AppleMediaSource];
 
     // Is there a matching media source?

IMBAppleMediaLibraryParserMessenger.m

@@ -131,6 +131,7 @@ - (NSArray *)parserInstancesWithError:(NSError **)outError
                       IMBAppleMediaLibraryParser *parser = (IMBAppleMediaLibraryParser *)[self newParser];
                       MLMediaType mediaType = [IMBAppleMediaLibraryParser MLMediaTypeForIMBMediaType:[myClass mediaType]];
                       parser.configuration = [myClass parserConfigurationFactory](mediaType);
+                      [parser initializeMediaLibrary];
                       [[myClass parsers] addObject:parser];
                   });
     return [myClass parsers];