New fix to Spotlight flicker issue. Still not ideal.

Cog.xcodeproj/project.pbxproj

@@ -603,6 +603,7 @@
 		5604D45A0D60349B004F5C5D /* SpotlightWindowController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SpotlightWindowController.h; path = Spotlight/SpotlightWindowController.h; sourceTree = "<group>"; };
 		5604D4F40D60726E004F5C5D /* SpotlightPlaylistEntry.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SpotlightPlaylistEntry.h; path = Spotlight/SpotlightPlaylistEntry.h; sourceTree = "<group>"; };
 		5604D4F50D60726E004F5C5D /* SpotlightPlaylistEntry.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = SpotlightPlaylistEntry.m; path = Spotlight/SpotlightPlaylistEntry.m; sourceTree = "<group>"; };
+		563EBE1D0D67987E00E12948 /* SpotlightTransformers.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SpotlightTransformers.h; path = Spotlight/SpotlightTransformers.h; sourceTree = "<group>"; };
 		56462DD80D61D71E000AB68C /* SpotlightPlaylistView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = SpotlightPlaylistView.h; path = Spotlight/SpotlightPlaylistView.h; sourceTree = "<group>"; };
 		56462DD90D61D71E000AB68C /* SpotlightPlaylistView.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = SpotlightPlaylistView.m; path = Spotlight/SpotlightPlaylistView.m; sourceTree = "<group>"; };
 		56462EAE0D6341F6000AB68C /* SpotlightTransformers.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; name = SpotlightTransformers.m; path = Spotlight/SpotlightTransformers.m; sourceTree = "<group>"; };
@@ -1110,6 +1111,7 @@
 				56DB08340D67166000453B6A /* Categories */,
 				56462EB00D634206000AB68C /* SpotlightPlaylistController.h */,
 				56462EB10D634206000AB68C /* SpotlightPlaylistController.m */,
+				563EBE1D0D67987E00E12948 /* SpotlightTransformers.h */,
 				56462EAE0D6341F6000AB68C /* SpotlightTransformers.m */,
 				5604D45A0D60349B004F5C5D /* SpotlightWindowController.h */,
 				5604D4590D60349B004F5C5D /* SpotlightWindowController.m */,

Spotlight/SpotlightPlaylistController.h

@@ -10,11 +10,8 @@
 #import "PlaylistController.h"
 
 @interface SpotlightPlaylistController : PlaylistController {
-    NSArray *oldObjects;
 }
 
 - (BOOL)tableView:(NSTableView *)tv writeRowsWithIndexes:(NSIndexSet *)rowIndexes toPasteboard:(NSPasteboard*)pboard;
 
-@property(retain) NSArray *oldObjects;
-
 @end

Spotlight/SpotlightPlaylistController.m

@@ -11,15 +11,6 @@
 
 @implementation SpotlightPlaylistController
 
-- (id)init
-{
-    if(self = [super init])
-    {
-        oldObjects = nil;
-    }
-	return self;
-}
-
 // Allow drag and drop from Spotlight into main playlist
 - (BOOL)tableView:(NSTableView *)tv
     writeRowsWithIndexes:(NSIndexSet *)rowIndexes
@@ -45,21 +36,4 @@
     return NSDragOperationNone;
 }
 
-// Don't update until something has been found
-- (NSArray *)arrangeObjects:(NSArray *)objects
-{
-    if((![spotlightWindowController.query isGathering]) || ([objects count] > 0))
-		self.oldObjects = [super arrangeObjects:objects];
-
-    return self.oldObjects;
-}
-
-- (void)dealloc
-{
-    [oldObjects release];
-    [super dealloc];
-}
-
-@synthesize oldObjects;
-
 @end

Spotlight/SpotlightTransformers.h

@@ -0,0 +1,20 @@
+//
+//  SpotlightTransformers.h
+//  Cog
+//
+//  Created by Matthew Grinshpun on 16/02/08.
+//  Copyright 2008 __MyCompanyName__. All rights reserved.
+//
+
+#import <Cocoa/Cocoa.h>
+@class SpotlightWindowController;
+
+@interface StringToURLTransformer: NSValueTransformer {}
+@end
+
+@interface PausingQueryTransformer: NSValueTransformer {
+    NSArray *oldResults;
+}
+
+@property(copy) NSArray *oldResults;
+@end

Spotlight/SpotlightTransformers.m

@@ -6,10 +6,8 @@
 //  Copyright 2008 Matthew Leon Grinshpun. All rights reserved.
 //
 
-#include <Cocoa/Cocoa.h>
-
-@interface StringToURLTransformer: NSValueTransformer {}
-@end
+#import "SpotlightTransformers.h"
+#import "SpotlightWindowController.h"
 
 @implementation StringToURLTransformer
 + (Class)transformedValueClass { return [NSURL class]; }
@@ -18,7 +16,7 @@
 // Convert from string to NSURL
 - (id)transformedValue:(id)value {
     if (value == nil) return nil;
-    
+
     return [NSURL URLWithString:value];
 }
 
@@ -28,4 +26,20 @@
     
     return [value absoluteString];
 }
+@end
+
+@implementation PausingQueryTransformer
++ (Class)transformedValueClass { return [NSArray class]; }
++ (BOOL)allowsReverseTransformation { return NO; }
+
+// Convert from string to NSURL
+- (id)transformedValue:(id)value {
+    if([(NSArray *)value count] > 0) {
+        self.oldResults = (NSArray *)value;
+    }
+    return self.oldResults;
+}
+
+@synthesize oldResults;
+
 @end

Spotlight/SpotlightWindowController.h

@@ -18,7 +18,6 @@
     NSMetadataQuery *query;
     NSString *searchString;
     NSString *spotlightSearchPath;
-    NSArray *oldResults;
 }
 
 - (IBAction)addToPlaylist:(id)sender;
@@ -32,6 +31,5 @@
 @property(retain) NSMetadataQuery *query;
 @property(copy) NSString *searchString;
 @property(copy) NSString *spotlightSearchPath;
-@property(retain) NSArray *oldResults;
 
 @end

Spotlight/SpotlightWindowController.m

@@ -13,6 +13,7 @@
 #import "NSArray+CogSort.h"
 #import "NSString+CogSort.h"
 #import "NSNumber+CogSort.h"
+#import "SpotlightTransformers.h"
 
 // Minimum length of a search string (searching for very small strings gets ugly)
 #define MINIMUM_SEARCH_STRING_LENGTH 3
@@ -36,6 +37,14 @@ static NSPredicate * musicOnlyPredicate = nil;
     NSDictionary *searchDefault = 
                         [NSDictionary dictionaryWithObject:homeDir
                                                     forKey:@"spotlightSearchPath"];
+                                                    
+    // Register value transformers
+    NSValueTransformer *stringToURLTransformer = [[[StringToURLTransformer alloc]init]autorelease];
+    [NSValueTransformer setValueTransformer:stringToURLTransformer
+                                    forName:@"StringToURLTransformer"];
+    NSValueTransformer *pausingQueryTransformer = [[[PausingQueryTransformer alloc] init] autorelease];
+    [NSValueTransformer setValueTransformer:pausingQueryTransformer forName:@"PausingQueryTransformer"];
+
     [defaults registerDefaults:searchDefault];
 }
 
@@ -54,7 +63,7 @@ static NSPredicate * musicOnlyPredicate = nil;
         [[NSSortDescriptor alloc]initWithKey:@"kMDItemAudioTrackNumber"
                                    ascending:YES
                                     selector:@selector(compareTrackNumbers:)],
-        Nil];
+        nil];
 	}
 
     return self;
@@ -198,7 +207,7 @@ static NSPredicate * musicOnlyPredicate = nil;
     }
     
     if ([subpredicates count] == 0)
-        return Nil;
+        return nil;
     else if ([subpredicates count] == 1)
         return [subpredicates objectAtIndex: 0];
     
@@ -226,7 +235,6 @@ static NSPredicate * musicOnlyPredicate = nil;
 	[self.query release];
 	[self.searchString release];
     [musicOnlyPredicate release];
-    [self.oldResults release];
 	[super dealloc];
 }
 
@@ -289,6 +297,4 @@ replacementObjectForResultObject:(NSMetadataItem*)result
 	}
 }
 
-@synthesize oldResults;
-
 @end