FeedDownload refactoring: everything parallel!

2019-01-25 02:12:15 +01:00
parent 8e90ca742f
commit d5354bb681
17 changed files with 427 additions and 330 deletions
--- a/README.md
+++ b/README.md
@@ -35,14 +35,9 @@ All in all, the software is in a usable state. The remaining features will be ad
 ToDo
 ----

- [ ] Preferences
-	- [ ] ~~Choose status bar icon?~~
-	- [ ] Display license info (e.g., RSXML)
-
-
 - [ ] Edit feed
 	- [ ] Show statistics
-		- [ ] How often gets the feed updated (min, max, avg)
+		- [x] How often gets the feed updated (min, max, avg)
 		- [ ] Automatically choose best interval?
 		- [ ] Show time of next update
 	- [ ] Feeds with authentication
--- a/baRSS/Categories/Feed+Ext.h
+++ b/baRSS/Categories/Feed+Ext.h
@@ -29,7 +29,7 @@
 + (instancetype)newFeedAndMetaInContext:(NSManagedObjectContext*)context;
 + (instancetype)appendToRootWithDefaultIntervalInContext:(NSManagedObjectContext*)moc;
 - (void)calculateAndSetIndexPathString;
- (void)resetArticleCountAndIndexPathString;
+- (void)calculateAndSetUnreadCount;
 - (void)updateWithRSS:(RSParsedFeed*)obj postUnreadCountChange:(BOOL)flag;
 // Article properties
 - (NSArray<FeedArticle*>*)sortedArticles;
@@ -37,5 +37,5 @@
 - (int)markAllItemsUnread;
 // Icon
 - (NSImage*)iconImage16;
- (BOOL)setIcon:(NSImage*)img replaceExisting:(BOOL)overwrite;
+- (BOOL)setIconImage:(NSImage*)img;
@end
--- a/baRSS/Categories/Feed+Ext.m
+++ b/baRSS/Categories/Feed+Ext.m
@@ -57,15 +57,11 @@
 		self.indexPath = pthStr;
 }

-/// Reset attributes @c articleCount, @c unreadCount, and @c indexPath.
- (void)resetArticleCountAndIndexPathString {
-	int16_t totalCount = (int16_t)self.articles.count;
-	int16_t unreadCount = (int16_t)[[self.articles valueForKeyPath:@"@sum.unread"] integerValue];
-	if (self.articleCount != totalCount)
-		self.articleCount = totalCount;
+/// Reset attributes @c unreadCount by counting number of articles. @note Remember to update global unread count.
+- (void)calculateAndSetUnreadCount {
+	int32_t unreadCount = (int32_t)[[self.articles valueForKeyPath:@"@sum.unread"] integerValue];
 	if (self.unreadCount != unreadCount)
-		self.unreadCount = unreadCount; // remember to update global total unread count
-	[self calculateAndSetIndexPathString];
+		self.unreadCount = unreadCount;
 }


@@ -89,12 +85,10 @@
 	[self addMissingArticles:obj updateLinks:urls]; // will remove links in 'urls' that should be kept
 	[self deleteArticlesWithLink:urls]; // remove old, outdated articles
 	// Get new total article count and post unread-count-change notification
-	int32_t totalCount = (int32_t)self.articles.count;
-	if (self.articleCount != totalCount)
-		self.articleCount = totalCount;
 	if (flag) {
-		NSNumber *cDiff = [NSNumber numberWithInteger:self.unreadCount - unreadBefore];
-		[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountChanged object:cDiff];
+		int32_t cDiff = self.unreadCount - unreadBefore;
+		if (cDiff != 0)
+			[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountChanged object:@(cDiff)];
 	}
 }

@@ -237,7 +231,7 @@
 			fa.unread = !readFlag;
 	}
 	int32_t oldCount = self.unreadCount;
-	int32_t newCount = (readFlag ? 0 : self.articleCount);
+	int32_t newCount = (readFlag ? 0 : (int32_t)self.articles.count);
 	if (self.unreadCount != newCount)
 		self.unreadCount = newCount;
 	return newCount - oldCount;
@@ -258,7 +252,7 @@
 		[img setSize:NSMakeSize(16, 16)];
 		return img;
 	}
-	else if (self.articleCount == 0)
+	else if (self.articles.count == 0)
 	{
 		static NSImage *warningIcon;
 		if (!warningIcon) {
@@ -277,22 +271,20 @@
 }

 /**
- Set (or overwrite) favicon icon or delete relationship if icon is @c nil.
+ Set favicon icon or delete relationship if @c img is not a valid image.
 
- @param overwrite If @c NO write image only if non is set already. Use @c YES if you want to @c nil.
+ @return @c YES if icon was updated (core data did change).
 */
- (BOOL)setIcon:(NSImage*)img replaceExisting:(BOOL)overwrite {
-	if (overwrite || !self.icon) { // write if forced or image empty
-		if (img && [img isValid]) {
-			if (!self.icon)
-				self.icon = [[FeedIcon alloc] initWithEntity:FeedIcon.entity insertIntoManagedObjectContext:self.managedObjectContext];
-			self.icon.icon = [img TIFFRepresentation];
-			return YES;
-		} else if (self.icon) {
-			[self.managedObjectContext deleteObject:self.icon];
-			self.icon = nil;
-			return YES;
-		}
+- (BOOL)setIconImage:(NSImage*)img {
+	if (img && [img isValid]) {
+		if (!self.icon)
+			self.icon = [[FeedIcon alloc] initWithEntity:FeedIcon.entity insertIntoManagedObjectContext:self.managedObjectContext];
+		self.icon.icon = [img TIFFRepresentation];
+		return YES;
+	} else if (self.icon) {
+		[self.managedObjectContext deleteObject:self.icon];
+		self.icon = nil;
+		return YES;
 	}
 	return NO;
 }
--- a/baRSS/Constants.h
+++ b/baRSS/Constants.h
@@ -29,11 +29,42 @@
 // TODO: List of hidden preferences for readme
 // TODO: Do we need to search for favicon in places other than '../favicon.ico'?

+/**
+ @c notification.object is @c NSNumber of type @c NSUInteger.
+ Represents number of feeds that are proccessed in background update. Sends @c 0 when all downloads are finished.
+ */
+static NSString *kNotificationBackgroundUpdateInProgress = @"baRSS-notification-background-update-in-progress";
+/**
+ @c notification.object is @c NSManagedObjectID of type @c Feed.
+ Called whenever download of a feed finished and object was modified (not if statusCode 304).
+ */
 static NSString *kNotificationFeedUpdated = @"baRSS-notification-feed-updated";
+/**
+ @c notification.object is @c NSManagedObjectID of type @c Feed.
+ Called whenever the icon attribute of an item was updated.
+ */
+static NSString *kNotificationFeedIconUpdated = @"baRSS-notification-feed-icon-updated";
+/**
+ @c notification.object is @c NSNumber of type @c BOOL.
+ @c YES if network became reachable. @c NO on connection lost.
+ */
 static NSString *kNotificationNetworkStatusChanged = @"baRSS-notification-network-status-changed";
+/**
+ @c notification.object is @c NSNumber of type @c NSInteger.
+ Represents a relative change (e.g., negative if items were marked read)
+ */
 static NSString *kNotificationTotalUnreadCountChanged = @"baRSS-notification-total-unread-count-changed";
+/**
+ @c notification.object is either @c nil or @c NSNumber of type @c NSInteger.
+ If new count is known an absoulte number is passed.
+ Else @c nil if count has to be fetched from core data.
+ */
 static NSString *kNotificationTotalUnreadCountReset = @"baRSS-notification-total-unread-count-reset";

+
+/**
+ Internal developer method for benchmarking purposes.
+ */
 extern uint64_t dispatch_benchmark(size_t count, void (^block)(void));
 //void benchmark(char *desc, dispatch_block_t b){printf("%s: %llu ns\n", desc, dispatch_benchmark(1, b));}
 #define benchmark(desc,block) printf(desc": %llu ns\n", dispatch_benchmark(1, block));
--- a/baRSS/DBv1.xcdatamodeld/DBv1.xcdatamodel/contents
+++ b/baRSS/DBv1.xcdatamodeld/DBv1.xcdatamodel/contents
@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="14315.18" systemVersion="17G3025" minimumToolsVersion="Automatic" sourceLanguage="Objective-C" userDefinedModelVersionIdentifier="v1">
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="14315.18" systemVersion="17G4015" minimumToolsVersion="Automatic" sourceLanguage="Objective-C" userDefinedModelVersionIdentifier="v1">
    <entity name="Feed" representedClassName="Feed" syncable="YES" codeGenerationType="class">
-        <attribute name="articleCount" optional="YES" attributeType="Integer 32" defaultValueString="0" usesScalarValueType="YES" syncable="YES"/>
        <attribute name="indexPath" optional="YES" attributeType="String" syncable="YES"/>
        <attribute name="link" optional="YES" attributeType="String" syncable="YES"/>
        <attribute name="subtitle" optional="YES" attributeType="String" syncable="YES"/>
@@ -48,7 +47,7 @@
        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="meta" inverseEntity="Feed" syncable="YES"/>
    </entity>
    <elements>
-        <element name="Feed" positionX="-278.84765625" positionY="-112.953125" width="128" height="195"/>
+        <element name="Feed" positionX="-278.84765625" positionY="-112.953125" width="128" height="180"/>
        <element name="FeedArticle" positionX="-96.77734375" positionY="-113.83984375" width="128" height="195"/>
        <element name="FeedGroup" positionX="-460.37890625" positionY="-111.62890625" width="130.52734375" height="150"/>
        <element name="FeedIcon" positionX="-202.79296875" positionY="137.71875" width="128" height="75"/>
--- a/baRSS/FeedDownload.h
+++ b/baRSS/FeedDownload.h
@@ -26,6 +26,10 @@
@class Feed;

@interface FeedDownload : NSObject
+@property (class, readonly) BOOL allowNetworkConnection;
+@property (class, readonly) BOOL isUpdating;
+@property (class, setter=setPaused:) BOOL isPaused;
+
 // Register for network change notifications
 + (void)registerNetworkChangeNotification;
 + (void)unregisterNetworkChangeNotification;
@@ -35,12 +39,8 @@
 // Downloading
 + (void)newFeed:(NSString *)urlStr askUser:(nonnull NSString*(^)(NSArray<RSHTMLMetadataFeedLink*> *list))askUser block:(nonnull void(^)(RSParsedFeed *parsed, NSError *error, NSHTTPURLResponse *response))block;
 + (void)autoDownloadAndParseURL:(NSString*)urlStr;
-+ (void)batchDownloadRSSAndFavicons:(NSArray<Feed*> *)list showErrorAlert:(BOOL)flag rssFinished:(void(^)(NSArray<Feed*> *successful, BOOL *cancelFavicons))blockXml finally:(void(^)(BOOL successful))blockFavicon;
-+ (void)downloadFavicon:(NSString*)urlStr finished:(void(^)(NSImage * _Nullable img))block ;
-// User interaction
-+ (BOOL)allowNetworkConnection;
-+ (BOOL)isPaused;
-+ (void)setPaused:(BOOL)flag;
+ (void)downloadFavicon:(NSString*)urlStr finished:(void(^)(NSImage * _Nullable img))block;
+ (void)batchDownloadFeeds:(NSArray<Feed*> *)list favicons:(BOOL)fav showErrorAlert:(BOOL)alert finally:(nullable os_block_t)block;
@end


--- a/baRSS/FeedDownload.m
+++ b/baRSS/FeedDownload.m
@@ -31,23 +31,24 @@

 static SCNetworkReachabilityRef _reachability = NULL;
 static BOOL _isReachable = NO;
+static BOOL _isUpdating = NO;
 static BOOL _updatePaused = NO;
 static BOOL _nextUpdateIsForced = NO;


@implementation FeedDownload

+
 #pragma mark - User Interaction -

 /// @return @c YES if current network state is reachable and updates are not paused by user.
-+ (BOOL)allowNetworkConnection {
-	return (_isReachable && !_updatePaused);
-}
+ (BOOL)allowNetworkConnection { return (_isReachable && !_updatePaused); }
+
+/// @return @c YES if batch update is running
+ (BOOL)isUpdating { return _isUpdating; }

 /// @return @c YES if update is paused by user.
-+ (BOOL)isPaused {
-	return _updatePaused;
-}
+ (BOOL)isPaused { return _updatePaused; }

 /// Set paused flag and cancel timer regardless of network connectivity.
 + (void)setPaused:(BOOL)flag {
@@ -94,7 +95,7 @@ static BOOL _nextUpdateIsForced = NO;
 	if (![self allowNetworkConnection]) // timer will restart once connection exists
 		return;
 	_nextUpdateIsForced = YES;
-	[self scheduleTimer:[NSDate dateWithTimeIntervalSinceNow:0.2]];
+	[self scheduleTimer:[NSDate dateWithTimeIntervalSinceNow:0.05]];
 }

 /**
@@ -130,31 +131,13 @@ static BOOL _nextUpdateIsForced = NO;
 	NSArray<Feed*> *list = [StoreCoordinator getListOfFeedsThatNeedUpdate:updateAll inContext:moc];
 	//NSAssert(list.count > 0, @"ERROR: Something went wrong, timer fired too early.");
 	
-	[FeedDownload batchUpdateFeeds:list showErrorAlert:NO finally:^(NSArray<Feed*> *successful, NSArray<Feed*> *failed) {
-		[self saveContext:moc andPostChanges:successful];
+	[self batchDownloadFeeds:list favicons:updateAll showErrorAlert:NO finally:^{
+		[StoreCoordinator saveContext:moc andParent:YES]; // save parents too ...
 		[moc reset];
-		if (updateAll) { // forced update will also download missing feed icons
-			NSArray<Feed*> *missingIcons = [StoreCoordinator listOfFeedsMissingIconsInContext:moc];
-			[self batchDownloadFavicons:missingIcons replaceExisting:NO finally:^{
-				[self saveContext:moc andPostChanges:successful];
-				[moc reset];
-			}];
-		}
 		[self resumeUpdates]; // always reset the timer
 	}];
 }

-/**
- Perform save on context and all parents. Then post @c FeedUpdated notification.
- */
-+ (void)saveContext:(NSManagedObjectContext*)moc andPostChanges:(NSArray<Feed*>*)changedFeeds {
-	[StoreCoordinator saveContext:moc andParent:YES];
-	if (changedFeeds && changedFeeds.count > 0) {
-		NSArray<NSManagedObjectID*> *list = [changedFeeds valueForKeyPath:@"objectID"];
-		[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationFeedUpdated object:list];
-	}
-}
-

 #pragma mark - Request Generator -

@@ -179,20 +162,20 @@ static BOOL _nextUpdateIsForced = NO;
 	req.cachePolicy = NSURLRequestReloadIgnoringLocalCacheData;
 	req.HTTPShouldHandleCookies = NO;
 //	req.timeoutInterval = 30;
-//	[req setValue:@"Mon, 10 Sep 2018 10:32:19 GMT" forHTTPHeaderField:@"If-Modified-Since"];
-//	[req setValue:@"wII2pETT9EGmlqyCHBFJpm25/7w" forHTTPHeaderField:@"If-None-Match"]; // ETag
 	return req;
 }

-/// @return New request with etag and modified headers set.
-+ (NSURLRequest*)newRequest:(FeedMeta*)meta {
+/// @return New request with etag and modified headers set (or not, if @c flag @c == @c YES ).
+ (NSURLRequest*)newRequest:(FeedMeta*)meta ignoreCache:(BOOL)flag {
 	NSMutableURLRequest *req = [self newRequestURL:meta.url];
-	NSString* etag = [meta.etag stringByReplacingOccurrencesOfString:@"-gzip" withString:@""];
-	if (meta.modified.length > 0)
-		[req setValue:meta.modified forHTTPHeaderField:@"If-Modified-Since"];
-	if (etag.length > 0)
-		[req setValue:etag forHTTPHeaderField:@"If-None-Match"]; // ETag
-	if (!_nextUpdateIsForced) // any FeedMeta-request that is not forced, is a background update
+	if (!flag) {
+		NSString* etag = [meta.etag stringByReplacingOccurrencesOfString:@"-gzip" withString:@""];
+		if (meta.modified.length > 0)
+			[req setValue:meta.modified forHTTPHeaderField:@"If-Modified-Since"];
+		if (etag.length > 0)
+			[req setValue:etag forHTTPHeaderField:@"If-None-Match"]; // ETag
+	}
+	if (!_nextUpdateIsForced) // any request that is not forced, is a background update
 		req.networkServiceType = NSURLNetworkServiceTypeBackground;
 	return req;
 }
@@ -246,7 +229,7 @@ static BOOL _nextUpdateIsForced = NO;
 @note @c askUser will not be called if url is XML already.
 
 @param urlStr XML URL or HTTP URL that will be parsed to find feed URLs.
- @param askUser Use @c list to present user a list of detected feed URLs. Always before @c block.
+ @param askUser Use @c list to present user a list of detected feed URLs.
 @param block Called after webpage has been fully parsed (including html autodetect).
 */
 + (void)newFeed:(NSString *)urlStr askUser:(nonnull NSString*(^)(NSArray<RSHTMLMetadataFeedLink*> *list))askUser block:(nonnull void(^)(RSParsedFeed *parsed, NSError *error, NSHTTPURLResponse *response))block {
@@ -273,41 +256,46 @@ static BOOL _nextUpdateIsForced = NO;
 }

 /**
- Start download request with existing @c Feed object. Reuses etag and modified headers.
+ Start download request with existing @c Feed object. Reuses etag and modified headers (unless articles count is 0).
+ 
+ @note Will post a @c kNotificationFeedUpdated notification if download was successful and @b not status code 304.
 
- @param feed @c Feed on which the update is executed.
- @param group Mutex to count completion of all downloads.
 @param alert If @c YES display Error Popup to user.
- @param successful Empty, mutable list that will be returned in @c batchUpdateFeeds:finally:showErrorAlert: finally block
- @param failed Empty, mutable list that will be returned in @c batchUpdateFeeds:finally:showErrorAlert: finally block
+ @param block Parameter @c success is only @c YES if download was successful or if status code is 304 (not modified).
 */
-+ (void)downloadFeed:(Feed*)feed group:(dispatch_group_t)group
-		  errorAlert:(BOOL)alert
-		  successful:(nonnull NSMutableArray<Feed*>*)successful
-			  failed:(nonnull NSMutableArray<Feed*>*)failed
-{
+ (void)backgroundUpdateFeed:(Feed*)feed showErrorAlert:(BOOL)alert finally:(nullable void(^)(BOOL success))block {
 	if (![self allowNetworkConnection]) {
-		[failed addObject:feed];
+		if (block) block(NO);
 		return;
 	}
-	dispatch_group_enter(group);
-	[self parseFeedRequest:[self newRequest:feed.meta] xmlBlock:nil feedBlock:^(RSParsedFeed *rss, NSError *error, NSHTTPURLResponse *response) {
-		if (!feed.isDeleted) {
-			if (error) {
-				if (alert) {
-					NSAlert *alertPopup = [NSAlert alertWithError:error];
-					alertPopup.informativeText = [NSString stringWithFormat:@"Error loading source: %@", response.URL.absoluteString];
-					[alertPopup runModal];
-				}
-				[feed.meta setErrorAndPostponeSchedule];
-				[failed addObject:feed];
-			} else {
-				[feed.meta setSucessfulWithResponse:response];
-				if (rss) [feed updateWithRSS:rss postUnreadCountChange:YES];
-				[successful addObject:feed]; // will be added even if statusCode == 304 (rss == nil)
+	NSManagedObjectID *oid = feed.objectID;
+	NSManagedObjectContext *moc = feed.managedObjectContext;
+	NSURLRequest *req = [self newRequest:feed.meta ignoreCache:(feed.articles.count == 0)];
+	NSString *reqURL = req.URL.absoluteString;
+	[self parseFeedRequest:req xmlBlock:nil feedBlock:^(RSParsedFeed *rss, NSError *error, NSHTTPURLResponse *response) {
+		Feed *f = [moc objectWithID:oid];
+		BOOL success = NO;
+		BOOL needsNotification = NO;
+		if (error) {
+			if (alert) {
+				NSAlert *alertPopup = [NSAlert alertWithError:error];
+				alertPopup.informativeText = [NSString stringWithFormat:@"Error loading source: %@", reqURL];
+				[alertPopup runModal];
+			}
+			// TODO: don't increase error count on forced update
+			[f.meta setErrorAndPostponeSchedule];
+		} else {
+			success = YES;
+			[f.meta setSucessfulWithResponse:response];
+			if (rss) {
+				[f updateWithRSS:rss postUnreadCountChange:YES];
+				needsNotification = YES;
 			}
 		}
-		dispatch_group_leave(group);
+		[StoreCoordinator saveContext:moc andParent:NO];
+		if (needsNotification)
+			[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationFeedUpdated object:oid];
+		if (block) block(success);
 	}];
 }

@@ -322,113 +310,88 @@ static BOOL _nextUpdateIsForced = NO;
 	NSManagedObjectContext *moc = [StoreCoordinator createChildContext];
 	Feed *f = [Feed appendToRootWithDefaultIntervalInContext:moc];
 	f.meta.url = url;
-	[self batchDownloadRSSAndFavicons:@[f] showErrorAlert:YES rssFinished:^(NSArray<Feed *> *successful, BOOL *cancelFavicons) {
-		if (successful.count == 0) {
-			*cancelFavicons = YES;
-		} else {
-			[self saveContext:moc andPostChanges:successful];
-		}
-	} finally:^(BOOL successful) {
-		if (successful) {
-			[StoreCoordinator saveContext:moc andParent:YES];
-		} else {
-			[moc rollback];
+	[self backgroundUpdateBoth:f favicon:YES alert:YES finally:^(BOOL successful){
+		if (!successful) {
+			[moc deleteObject:f.group];
 		}
+		[StoreCoordinator saveContext:moc andParent:YES];
 		[moc reset];
 	}];
 }

 /**
- Perform a download /update request for the feed data and download missing favicons.
- If neither block is set, favicons will be downloaded and stored automatically.
- However, you should handle the case
+ Start download of feed xml, then continue with favicon download (optional).
 
- @param list List of feeds that need update. Its sufficient if @c feed.meta.url is set.
- @param flag If @c YES display Error Popup to user.
- @param blockXml Called after XML is downloaded and parsed.
-                 Parameter @c successful is list of feeds that were downloaded.
-                 Set @c cancelFavicons to @c YES to call @c finally block without downloading favicons. Default: @c NO.
- @param blockFavicon Called after all downloads are finished.
-                     @c successful is set to @c NO if favicon download was prohibited in @c blockXml or list is empty.
+ @param fav If @c YES continue with favicon download after xml download finished.
+ @param alert If @c YES display Error Popup to user.
+ @param block Parameter @c success is @c YES if xml download succeeded (regardless of favicon result).
 */
-+ (void)batchDownloadRSSAndFavicons:(NSArray<Feed*> *)list
-					 showErrorAlert:(BOOL)flag
-						rssFinished:(void(^)(NSArray<Feed*> *successful, BOOL * cancelFavicons))blockXml
-							finally:(void(^)(BOOL successful))blockFavicon
-{
-	[self batchUpdateFeeds:list showErrorAlert:flag finally:^(NSArray<Feed*> *successful, NSArray<Feed*> *failed) {
-		BOOL cancelFaviconsDownload = NO;
-		if (blockXml) {
-			blockXml(successful, &cancelFaviconsDownload);
-		}
-		if (cancelFaviconsDownload || successful.count == 0) {
-			if (blockFavicon) blockFavicon(NO);
-		} else {
-			[self batchDownloadFavicons:successful replaceExisting:NO finally:^{
-				if (blockFavicon) blockFavicon(YES);
+ (void)backgroundUpdateBoth:(Feed*)feed favicon:(BOOL)fav alert:(BOOL)alert finally:(nullable void(^)(BOOL success))block {
+	[self backgroundUpdateFeed:feed showErrorAlert:alert finally:^(BOOL success) {
+		if (fav && success) {
+			[self backgroundUpdateFavicon:feed replaceExisting:NO finally:^{
+				if (block) block(YES);
 			}];
+		} else {
+			if (block) block(success);
 		}
 	}];
 }

 /**
- Create download list of feed URLs and download them all at once. Finally, notify when all finished.
+ Start download of all feeds in list. Either with or without favicons.

 @param list Download list using @c feed.meta.url as download url. (while reusing etag and modified headers)
- @param flag If @c YES display Error Popup to user.
- @param block Called after all downloads finished @b OR if list is empty (in that case both parameters are @c nil ).
- */
-+ (void)batchUpdateFeeds:(NSArray<Feed*> *)list showErrorAlert:(BOOL)flag finally:(void(^)(NSArray<Feed*> *successful, NSArray<Feed*> *failed))block {
-	if (!list || list.count == 0) {
-		if (block) block(nil, nil);
-		return;
-	}
-	// else, process all feed items in a batch
-	NSMutableArray<Feed*> *successful = [NSMutableArray arrayWithCapacity:list.count];
-	NSMutableArray<Feed*> *failed = [NSMutableArray arrayWithCapacity:list.count];
-	
-	dispatch_group_t group = dispatch_group_create();
-	for (Feed *feed in list) {
-		[self downloadFeed:feed group:group errorAlert:flag successful:successful failed:failed];
-	}
-	dispatch_group_notify(group, dispatch_get_main_queue(), ^{
-		if (block) block(successful, failed);
-	});
-}
-
-
-#pragma mark - Favicon -
-
-
-/**
- Create download list of @c favicon.ico URLs and save downloaded images to persistent store.
- 
- @param list Download list using @c feed.link as download url. If empty fall back to @c feed.meta.url
- @param flag If @c YES display Error Popup to user.
+ @param fav If @c YES continue with favicon download after xml download finished.
+ @param alert If @c YES display Error Popup to user.
 @param block Called after all downloads finished.
 */
-+ (void)batchDownloadFavicons:(NSArray<Feed*> *)list replaceExisting:(BOOL)flag finally:(os_block_t)block {
+ (void)batchDownloadFeeds:(NSArray<Feed*> *)list favicons:(BOOL)fav showErrorAlert:(BOOL)alert finally:(nullable os_block_t)block {
+	_isUpdating = YES;
+	[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationBackgroundUpdateInProgress object:@(list.count)];
 	dispatch_group_t group = dispatch_group_create();
 	for (Feed *f in list) {
-		if (!flag && f.icon != nil) {
-			continue; // skip existing icons if replace == NO
-		}
-		NSManagedObjectID *oid = f.objectID;
-		NSManagedObjectContext *moc = f.managedObjectContext;
-		NSString *faviconURL = (f.link.length > 0 ? f.link : f.meta.url);
-		
 		dispatch_group_enter(group);
-		[self downloadFavicon:faviconURL finished:^(NSImage *img) {
-			Feed *feed = [moc objectWithID:oid]; // should also work if context was reset
-			[feed setIcon:img replaceExisting:flag];
+		[self backgroundUpdateBoth:f favicon:fav alert:alert finally:^(BOOL success){
 			dispatch_group_leave(group);
 		}];
 	}
 	dispatch_group_notify(group, dispatch_get_main_queue(), ^{
 		if (block) block();
+		_isUpdating = NO;
+		[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationBackgroundUpdateInProgress object:@(0)];
 	});
 }

+
+#pragma mark - Download Favicon -
+
+
+/**
+ Start favicon download request on existing @c Feed object.
+ 
+ @note Will post a @c kNotificationFeedIconUpdated notification if icon was updated.
+ 
+ @param overwrite If @c YES and icon is present already, @c block will return immediatelly.
+ */
+ (void)backgroundUpdateFavicon:(Feed*)feed replaceExisting:(BOOL)overwrite finally:(nullable os_block_t)block {
+	if (!overwrite && feed.icon != nil) {
+		if (block) block();
+		return; // skip existing icons if replace == NO
+	}
+	NSManagedObjectID *oid = feed.objectID;
+	NSManagedObjectContext *moc = feed.managedObjectContext;
+	NSString *faviconURL = (feed.link.length > 0 ? feed.link : feed.meta.url);
+	[self downloadFavicon:faviconURL finished:^(NSImage *img) {
+		Feed *f = [moc objectWithID:oid];
+		if (f && [f setIconImage:img]) {
+			[StoreCoordinator saveContext:moc andParent:NO];
+			[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationFeedIconUpdated object:oid];
+		}
+		if (block) block();
+	}];
+}
+
 /// Download favicon located at http://.../ @c favicon.ico. Callback @c block will be called on main thread.
 + (void)downloadFavicon:(NSString*)urlStr finished:(void(^)(NSImage * _Nullable img))block {
 	dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
--- a/baRSS/Preferences/Feeds
+++ b/baRSS/Preferences/Feeds
@@ -126,7 +126,7 @@
 	if (self.didDownloadFeed) {
 		[meta setEtag:self.httpEtag modified:self.httpDate];
 		[feed updateWithRSS:self.feedResult postUnreadCountChange:YES];
-		[feed setIcon:self.favicon replaceExisting:YES];
+		[feed setIconImage:self.favicon];
 	}
 }

@@ -161,7 +161,6 @@
 	if (self.modalSheet.didCloseAndCancel)
 		return;
 	[self preDownload];
-	// TODO: parse webpage to find feed links instead (automatic link detection)
 	[FeedDownload newFeed:self.previousURL askUser:^NSString *(NSArray<RSHTMLMetadataFeedLink *> *list) {
 		return [self letUserChooseXmlUrlFromList:list];
 	} block:^(RSParsedFeed *result, NSError *error, NSHTTPURLResponse* response) {
--- a/baRSS/Preferences/Feeds
+++ b/baRSS/Preferences/Feeds
@@ -26,6 +26,6 @@
@class Feed;

@interface OpmlExport : NSObject
-+ (void)showImportDialog:(NSWindow*)window withTreeController:(NSTreeController*)tree;
+ (void)showImportDialog:(NSWindow*)window withContext:(NSManagedObjectContext*)moc;
 + (void)showExportDialog:(NSWindow*)window withContext:(NSManagedObjectContext*)moc;
@end
--- a/baRSS/Preferences/Feeds
+++ b/baRSS/Preferences/Feeds
@@ -31,13 +31,22 @@

 #pragma mark - Open & Save Panel

-/// Display Open File Panel to select @c .opml file.
-+ (void)showImportDialog:(NSWindow*)window withContext:(NSManagedObjectContext*)moc success:(nullable void(^)(NSArray<Feed*> *added))block {
+/// Display Open File Panel to select @c .opml file. Perform web requests (feed data & icon) within a single undo group.
+ (void)showImportDialog:(NSWindow*)window withContext:(NSManagedObjectContext*)moc {
 	NSOpenPanel *op = [NSOpenPanel openPanel];
 	op.allowedFileTypes = @[@"opml"];
 	[op beginSheetModalForWindow:window completionHandler:^(NSModalResponse result) {
 		if (result == NSModalResponseOK) {
-			[self importFeedData:op.URL inContext:moc success:block];
+			NSData *data = [NSData dataWithContentsOfURL:op.URL];
+			RSXMLData *xml = [[RSXMLData alloc] initWithData:data urlString:@"opml-file-import"];
+			RSOPMLParser *parser = [RSOPMLParser parserWithXMLData:xml];
+			[parser parseAsync:^(RSOPMLItem * _Nullable doc, NSError * _Nullable error) {
+				if (error) {
+					[NSApp presentError:error];
+				} else {
+					[self importOPMLDocument:doc inContext:moc];
+				}
+			}];
 		}
 	}];
 }
@@ -67,28 +76,6 @@
 	}];
 }

-/// Handle import dialog and perform web requests (feed data & icon). Creates a single undo group.
-+ (void)showImportDialog:(NSWindow*)window withTreeController:(NSTreeController*)tree {
-	NSManagedObjectContext *moc = tree.managedObjectContext;
-	//[moc refreshAllObjects];
-	[moc.undoManager beginUndoGrouping];
-	[self showImportDialog:window withContext:moc success:^(NSArray<Feed *> *added) {
-		[StoreCoordinator saveContext:moc andParent:YES];
-		[FeedDownload batchDownloadRSSAndFavicons:added showErrorAlert:YES rssFinished:^(NSArray<Feed *> *successful, BOOL *cancelFavicons) {
-			if (successful.count > 0)
-				[StoreCoordinator saveContext:moc andParent:YES];
-			// we need to post a reset, since after deletion total unread count is wrong
-			[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountReset object:nil];
-		} finally:^(BOOL successful) {
-			[moc.undoManager endUndoGrouping];
-			if (successful) {
-				[StoreCoordinator saveContext:moc andParent:YES];
-				[tree rearrangeObjects]; // rearrange, because no new items appread instead only icon attrib changed
-			}
-		}];
-	}];
-}
-

 #pragma mark - Import

@@ -98,9 +85,9 @@
 If user chooses to replace existing items, perform core data request to delete all feeds.

 @param document Used to count feed items that will be imported
- @return @c NO if user clicks 'Cancel' button. @c YES otherwise.
+ @return @c -1: User clicked 'Cancel' button. @c 0: Append items. @c 1: Overwrite items.
 */
-+ (BOOL)askToAppendOrOverwriteAlert:(RSOPMLItem*)document inContext:(NSManagedObjectContext*)moc {
+ (NSInteger)askToAppendOrOverwriteAlert:(RSOPMLItem*)document inContext:(NSManagedObjectContext*)moc {
 	NSUInteger count = [self recursiveNumberOfFeeds:document];
 	NSAlert *alert = [[NSAlert alloc] init];
 	alert.messageText = [NSString stringWithFormat:NSLocalizedString(@"Import of %lu feed items", nil), count];
@@ -109,42 +96,43 @@
 	[alert addButtonWithTitle:NSLocalizedString(@"Cancel", nil)];
 	alert.accessoryView = [self radioGroupCreate:@[NSLocalizedString(@"Append", nil),
 												   NSLocalizedString(@"Overwrite", nil)]];
-	NSModalResponse code = [alert runModal];
-	if (code == NSAlertSecondButtonReturn) { // cancel button
-		return NO;
+	
+	if ([alert runModal] == NSAlertFirstButtonReturn) {
+		return [self radioGroupSelection:alert.accessoryView];
 	}
-	if ([self radioGroupSelection:alert.accessoryView] == 1) { // overwrite selected
-		for (FeedGroup *g in [StoreCoordinator sortedListOfRootObjectsInContext:moc]) {
-			[moc deleteObject:g];
-		}
-	}
-	return YES;
+	return -1; // cancel button
 }

 /**
 Perform import of @c FeedGroup items.
-
- @param block Called after import finished. Parameter @c added is the list of inserted @c Feed items.
 */
-+ (void)importFeedData:(NSURL*)fileURL inContext:(NSManagedObjectContext*)moc success:(nullable void(^)(NSArray<Feed*> *added))block {
-	NSData *data = [NSData dataWithContentsOfURL:fileURL];
-	RSXMLData *xml = [[RSXMLData alloc] initWithData:data urlString:@"opml-file-import"];
-	RSOPMLParser *parser = [RSOPMLParser parserWithXMLData:xml];
-	[parser parseAsync:^(RSOPMLItem * _Nullable doc, NSError * _Nullable error) {
-		if (error) {
-			[NSApp presentError:error];
-		} else if ([self askToAppendOrOverwriteAlert:doc inContext:moc]) {
-			NSMutableArray<Feed*> *list = [NSMutableArray array];
-			int32_t idx = 0;
-			if (moc.deletedObjects.count == 0) // if there are deleted objects, user choose to overwrite all items
-				idx = (int32_t)[StoreCoordinator numberRootItemsInContext:moc];
+ (void)importOPMLDocument:(RSOPMLItem*)doc inContext:(NSManagedObjectContext*)moc {
+	NSInteger select = [self askToAppendOrOverwriteAlert:doc inContext:moc];
+	if (select < 0 || select > 1) // not a valid selection (or cancel button)
+		return;
 	
-			for (RSOPMLItem *item in doc.children) {
-				[self importFeed:item parent:nil index:idx inContext:moc appendToList:list];
-				idx += 1;
-			}
-			if (block) block(list);
+	[moc.undoManager beginUndoGrouping];
+	
+	int32_t idx = 0;
+	if (select == 1) { // overwrite selected
+		for (FeedGroup *fg in [StoreCoordinator sortedListOfRootObjectsInContext:moc]) {
+			[moc deleteObject:fg]; // Not a batch delete request to support undo
 		}
+		[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountReset object:@(0)];
+	} else {
+		idx = (int32_t)[StoreCoordinator numberRootItemsInContext:moc];
+	}
+	
+	NSMutableArray<Feed*> *list = [NSMutableArray array];
+	for (RSOPMLItem *item in doc.children) {
+		[self importFeed:item parent:nil index:idx inContext:moc appendToList:list];
+		idx += 1;
+	}
+	// Persist state, because on crash we have at least inserted items (without articles & icons)
+	[StoreCoordinator saveContext:moc andParent:YES];
+	[FeedDownload batchDownloadFeeds:list favicons:YES showErrorAlert:YES finally:^{
+		[StoreCoordinator saveContext:moc andParent:YES];
+		[moc.undoManager endUndoGrouping];
 	}];
 }

@@ -206,9 +194,9 @@
 */
 + (NSXMLDocument*)xmlDocumentForFeeds:(NSArray<FeedGroup*>*)list hierarchical:(BOOL)flag {
 	NSXMLElement *head = [NSXMLElement elementWithName:@"head"];
-	[head addChild:[NSXMLElement elementWithName:@"title" stringValue:@"baRSS feeds"]];
-	[head addChild:[NSXMLElement elementWithName:@"ownerName" stringValue:@"baRSS"]];
-	[head addChild:[NSXMLElement elementWithName:@"dateCreated" stringValue:[self currentDayAsStringISO8601:YES]]];
+	head.children = @[[NSXMLElement elementWithName:@"title" stringValue:@"baRSS feeds"],
+					  [NSXMLElement elementWithName:@"ownerName" stringValue:@"baRSS"],
+					  [NSXMLElement elementWithName:@"dateCreated" stringValue:[self currentDayAsStringISO8601:YES]] ];
 	
 	NSXMLElement *body = [NSXMLElement elementWithName:@"body"];
 	for (FeedGroup *item in list) {
@@ -216,9 +204,8 @@
 	}
 	
 	NSXMLElement *opml = [NSXMLElement elementWithName:@"opml"];
-	[opml addAttribute:[NSXMLNode attributeWithName:@"version" stringValue:@"1.0"]];
-	[opml addChild:head];
-	[opml addChild:body];
+	opml.attributes = @[[NSXMLNode attributeWithName:@"version" stringValue:@"1.0"]];
+	opml.children = @[head, body];
 	
 	NSXMLDocument *xml = [NSXMLDocument documentWithRootElement:opml];
 	xml.version = @"1.0";
--- a/baRSS/Preferences/Feeds
+++ b/baRSS/Preferences/Feeds
@@ -27,10 +27,13 @@
 #import "Feed+Ext.h"
 #import "FeedGroup+Ext.h"
 #import "OpmlExport.h"
+#import "FeedDownload.h"

@interface SettingsFeeds ()
@property (weak) IBOutlet NSOutlineView *outlineView;
@property (weak) IBOutlet NSTreeController *dataStore;
+@property (weak) IBOutlet NSProgressIndicator *spinner;
+@property (weak) IBOutlet NSTextField *spinnerLabel;

@property (strong) NSArray<NSTreeNode*> *currentlyDraggedNodes;
@property (strong) NSUndoManager *undoManager;
@@ -44,6 +47,7 @@ static NSString *dragNodeType = @"baRSS-feed-drag";

 - (void)viewDidLoad {
    [super viewDidLoad];
+	[self activateSpinner:([FeedDownload isUpdating] ? -1 : 0)]; // start spinner if update is in progress when preferences open
 	[self.outlineView registerForDraggedTypes:[NSArray arrayWithObject:dragNodeType]];
 	[self.dataStore setSortDescriptors:[NSArray arrayWithObject:[NSSortDescriptor sortDescriptorWithKey:@"sortIndex" ascending:YES]]];
 	
@@ -53,9 +57,61 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 	
 	self.dataStore.managedObjectContext = [StoreCoordinator createChildContext];
 	self.dataStore.managedObjectContext.undoManager = self.undoManager;
-	self.dataStore.managedObjectContext.automaticallyMergesChangesFromParent = NO;
+	
+	// Register for notifications
+	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateIcon:) name:kNotificationFeedUpdated object:nil];
+	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateIcon:) name:kNotificationFeedIconUpdated object:nil];
+	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(updateInProgress:) name:kNotificationBackgroundUpdateInProgress object:nil];
 }

+- (void)dealloc {
+	[[NSNotificationCenter defaultCenter] removeObserver:self];
+}
+
+
+#pragma mark - Notification callback methods
+
+
+/// Callback method fired when feeds have been updated in the background.
+- (void)updateIcon:(NSNotification*)notify {
+	NSManagedObjectID *oid = notify.object;
+	NSManagedObjectContext *moc = self.dataStore.managedObjectContext;
+	Feed *feed = [moc objectRegisteredForID:oid];
+	if (feed) {
+		if (self.undoManager.groupingLevel == 0) // don't mess around if user is editing something
+			[moc refreshObject:feed mergeChanges:YES];
+		[self.dataStore rearrangeObjects];
+	}
+}
+
+/// Callback method fired when background feed update begins and ends.
+- (void)updateInProgress:(NSNotification*)notify {
+	[self activateSpinner:[notify.object integerValue]];
+}
+
+/// Start or stop activity spinner (will run on main thread). If @c c @c == @c 0 stop spinner.
+- (void)activateSpinner:(NSInteger)c {
+	dispatch_async(dispatch_get_main_queue(), ^{
+		if (c == 0) {
+			[self.spinner stopAnimation:nil];
+			self.spinnerLabel.stringValue = @"";
+		} else {
+			[self.spinner startAnimation:nil];
+			if (c < 0) { // unknown number of feeds
+				self.spinnerLabel.stringValue = NSLocalizedString(@"Updating feeds …", nil);
+			} else if (c == 1) {
+				self.spinnerLabel.stringValue = NSLocalizedString(@"Updating 1 feed …", nil);
+			} else {
+				self.spinnerLabel.stringValue = [NSString stringWithFormat:NSLocalizedString(@"Updating %lu feeds …", nil), c];
+			}
+		}
+	});
+}
+
+
+#pragma mark - Persist state
+
+
 /**
 Refresh current context from parent context and start new undo grouping.
 @note Should be balanced with @c endCoreDataChangeUndoChanges:
@@ -89,10 +145,13 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 After the user did undo or redo we can't ensure integrity without doing some additional work.
 */
 - (void)saveWithUnpredictableChange {
-	NSSet<Feed*> *arr = [self.dataStore.managedObjectContext.insertedObjects
-						 filteredSetUsingPredicate:[NSPredicate predicateWithFormat:@"class == %@", [Feed class]]];
+	// dont use unless you merge changes from main
+//	NSManagedObjectContext *moc = self.dataStore.managedObjectContext;
+//	NSPredicate *pred = [NSPredicate predicateWithFormat:@"class == %@", [FeedArticle class]];
+//	NSInteger del = [[[moc.deletedObjects filteredSetUsingPredicate:pred] valueForKeyPath:@"@sum.unread"] integerValue];
+//	NSInteger ins = [[[moc.insertedObjects filteredSetUsingPredicate:pred] valueForKeyPath:@"@sum.unread"] integerValue];
+//	NSLog(@"%ld, %ld", del, ins);
 	[StoreCoordinator saveContext:self.dataStore.managedObjectContext andParent:YES];
-	[StoreCoordinator restoreFeedCountsAndIndexPaths:[arr valueForKeyPath:@"objectID"]]; // main context will not create undo group
 	[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountReset object:nil];
 	[self.dataStore rearrangeObjects]; // update ordering
 }
@@ -150,7 +209,7 @@ static NSString *dragNodeType = @"baRSS-feed-drag";
 	if ([sender.menu popUpMenuPositioningItem:nil atLocation:NSMakePoint(0,sender.frame.size.height) inView:sender]) {
 		NSInteger tag = sender.menu.highlightedItem.tag;
 		if (tag == 101) {
-			[OpmlExport showImportDialog:self.view.window withTreeController:self.dataStore];
+			[OpmlExport showImportDialog:self.view.window withContext:self.dataStore.managedObjectContext];
 		} else if (tag == 102) {
 			[OpmlExport showExportDialog:self.view.window withContext:self.dataStore.managedObjectContext];
 		}
@@ -323,8 +382,10 @@ static NSString *dragNodeType = @"baRSS-feed-drag";

 /// Returning @c NO will result in a Action-Not-Available-Buzzer sound
 - (BOOL)respondsToSelector:(SEL)aSelector {
-	if (aSelector == @selector(undo:)) return [self.undoManager canUndo] && self.undoManager.groupingLevel == 0;
-	if (aSelector == @selector(redo:)) return [self.undoManager canRedo] && self.undoManager.groupingLevel == 0;
+	if (aSelector == @selector(undo:))
+		return [self.undoManager canUndo] && self.undoManager.groupingLevel == 0 && ![FeedDownload isUpdating];
+	if (aSelector == @selector(redo:))
+		return [self.undoManager canRedo] && self.undoManager.groupingLevel == 0 && ![FeedDownload isUpdating];
 	if (aSelector == @selector(copy:) || aSelector == @selector(enterPressed:)) {
 		BOOL outlineHasFocus = [[self.view.window firstResponder] isKindOfClass:[NSOutlineView class]];
 		BOOL hasSelection = (self.dataStore.selectedNodes.count > 0);
--- a/baRSS/Preferences/Feeds
+++ b/baRSS/Preferences/Feeds
@@ -10,6 +10,8 @@
            <connections>
                <outlet property="dataStore" destination="JPf-gH-wxm" id="9qy-D6-L4R"/>
                <outlet property="outlineView" destination="wP9-Vd-f79" id="nKf-fc-7Np"/>
+                <outlet property="spinner" destination="fos-vP-s2s" id="zZp-Op-ftK"/>
+                <outlet property="spinnerLabel" destination="44U-lx-hnq" id="GGB-H5-7LV"/>
                <outlet property="view" destination="zfc-Ie-Sdx" id="65R-bK-FDI"/>
            </connections>
        </customObject>
@@ -182,20 +184,8 @@ CA
                        <binding destination="JPf-gH-wxm" name="enabled" keyPath="canRemove" id="XYY-gx-tiN"/>
                    </connections>
                </button>
-                <button toolTip="Add new line separator" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="kn9-pd-A47">
-                    <rect key="frame" x="96" y="-1" width="25" height="23"/>
-                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
-                    <buttonCell key="cell" type="smallSquare" title="---" alternateTitle="Add separator" bezelStyle="smallSquare" image="NSPathTemplate" alignment="center" lineBreakMode="truncatingTail" state="on" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="r9B-nl-XkX">
-                        <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
-                        <font key="font" metaFont="system"/>
-                    </buttonCell>
-                    <connections>
-                        <action selector="addSeparator:" target="-2" id="dVQ-ge-moI"/>
-                        <binding destination="JPf-gH-wxm" name="enabled" keyPath="canInsert" id="2aK-XU-RUD"/>
-                    </connections>
-                </button>
                <button toolTip="Add new grouping folder" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="jPg-sh-1Az">
-                    <rect key="frame" x="72" y="-1" width="25" height="23"/>
+                    <rect key="frame" x="64" y="-1" width="25" height="23"/>
                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                    <buttonCell key="cell" type="smallSquare" alternateTitle="Add group" bezelStyle="smallSquare" image="NSPathTemplate" imagePosition="overlaps" alignment="center" lineBreakMode="truncatingTail" state="on" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="rPk-c8-lMe">
                        <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
@@ -208,9 +198,21 @@ CA
                        <binding destination="JPf-gH-wxm" name="enabled" keyPath="canInsert" id="JCF-ey-YUL"/>
                    </connections>
                </button>
+                <button toolTip="Add new line separator" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="kn9-pd-A47">
+                    <rect key="frame" x="88" y="-1" width="25" height="23"/>
+                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                    <buttonCell key="cell" type="smallSquare" title="---" alternateTitle="Add separator" bezelStyle="smallSquare" image="NSPathTemplate" alignment="center" lineBreakMode="truncatingTail" state="on" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="r9B-nl-XkX">
+                        <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
+                        <font key="font" metaFont="system"/>
+                    </buttonCell>
+                    <connections>
+                        <action selector="addSeparator:" target="-2" id="dVQ-ge-moI"/>
+                        <binding destination="JPf-gH-wxm" name="enabled" keyPath="canInsert" id="2aK-XU-RUD"/>
+                    </connections>
+                </button>
                <button toolTip="Import or Export data" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="6ul-3K-fOy">
-                    <rect key="frame" x="295" y="-1" width="25" height="23"/>
-                    <autoresizingMask key="autoresizingMask" flexibleMinX="YES" flexibleMaxY="YES"/>
+                    <rect key="frame" x="128" y="-1" width="25" height="23"/>
+                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                    <buttonCell key="cell" type="smallSquare" alternateTitle="Export" bezelStyle="smallSquare" image="NSShareTemplate" imagePosition="overlaps" alignment="center" lineBreakMode="truncatingTail" state="on" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="nrA-7c-1sL">
                        <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                        <font key="font" metaFont="system"/>
@@ -219,6 +221,19 @@ CA
                        <action selector="shareMenu:" target="-2" id="JJq-7D-Bti"/>
                    </connections>
                </button>
+                <progressIndicator wantsLayer="YES" horizontalHuggingPriority="750" verticalHuggingPriority="750" fixedFrame="YES" maxValue="100" displayedWhenStopped="NO" bezeled="NO" indeterminate="YES" controlSize="small" style="spinning" translatesAutoresizingMaskIntoConstraints="NO" id="fos-vP-s2s">
+                    <rect key="frame" x="168" y="3" width="16" height="16"/>
+                    <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
+                </progressIndicator>
+                <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="44U-lx-hnq">
+                    <rect key="frame" x="190" y="4" width="112" height="14"/>
+                    <autoresizingMask key="autoresizingMask" widthSizable="YES" flexibleMaxY="YES"/>
+                    <textFieldCell key="cell" lineBreakMode="clipping" title="&lt;string&gt;" id="yyA-K6-M3v">
+                        <font key="font" metaFont="smallSystem"/>
+                        <color key="textColor" name="systemGrayColor" catalog="System" colorSpace="catalog"/>
+                        <color key="backgroundColor" name="textBackgroundColor" catalog="System" colorSpace="catalog"/>
+                    </textFieldCell>
+                </textField>
            </subviews>
            <point key="canvasLocation" x="27" y="882.5"/>
        </customView>
--- a/baRSS/Preferences/General
+++ b/baRSS/Preferences/General
@@ -25,6 +25,7 @@
 #import "BarMenu.h"
 #import "UserPrefs.h"
 #import "StoreCoordinator.h"
+#import "Constants.h"

 #import <ServiceManagement/ServiceManagement.h>

@@ -60,8 +61,10 @@
 }

 - (IBAction)fixCache:(NSButton *)sender {
-	[StoreCoordinator deleteUnreferencedFeeds];
-	[StoreCoordinator restoreFeedCountsAndIndexPaths:nil];
+	NSUInteger deleted = [StoreCoordinator deleteUnreferenced];
+	[StoreCoordinator restoreFeedCountsAndIndexPaths];
+	[[NSNotificationCenter defaultCenter] postNotificationName:kNotificationTotalUnreadCountReset object:nil];
+	NSLog(@"Removed %lu unreferenced core data entries.", deleted);
 }

 - (IBAction)changeMenuBarIconSetting:(NSButton*)sender {
--- a/Menu/BarMenu.h
+++ b/Menu/BarMenu.h
@@ -24,5 +24,4 @@

@interface BarMenu : NSObject <NSMenuDelegate>
 - (void)updateBarIcon;
- (void)asyncReloadUnreadCountAndUpdateBarIcon;
@end
--- a/Menu/BarMenu.m
+++ b/Menu/BarMenu.m
@@ -54,13 +54,14 @@
 	// Unread counter
 	self.unreadCountTotal = 0;
 	[self updateBarIcon];
-	[self asyncReloadUnreadCountAndUpdateBarIcon];
+	[self asyncReloadUnreadCountAndUpdateBarIcon:nil];
 	
 	// Register for notifications
 	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(feedUpdated:) name:kNotificationFeedUpdated object:nil];
+	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(feedIconUpdated:) name:kNotificationFeedIconUpdated object:nil];
 	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(networkChanged:) name:kNotificationNetworkStatusChanged object:nil];
 	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(unreadCountChanged:) name:kNotificationTotalUnreadCountChanged object:nil];
-	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(asyncReloadUnreadCountAndUpdateBarIcon) name:kNotificationTotalUnreadCountReset object:nil];
+	[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(asyncReloadUnreadCountAndUpdateBarIcon:) name:kNotificationTotalUnreadCountReset object:nil];
 	return self;
 }

@@ -70,12 +71,20 @@

 #pragma mark - Update Menu Bar Icon

-/// Regardless of current unread count, perform new core data fetch on total unread count and update icon.
- (void)asyncReloadUnreadCountAndUpdateBarIcon {
-	dispatch_async(dispatch_get_main_queue(), ^{
-		self.unreadCountTotal = [StoreCoordinator unreadCountForIndexPathString:nil];
+/**
+ If notification has @c object use this object to set unread count directly.
+ If @c object is @c nil perform core data fetch on total unread count and update icon.
+ */
+- (void)asyncReloadUnreadCountAndUpdateBarIcon:(NSNotification*)notify {
+	if (notify.object) { // set unread count directly
+		self.unreadCountTotal = [[notify object] integerValue];
 		[self updateBarIcon];
-	});
+	} else {
+		dispatch_async(dispatch_get_main_queue(), ^{
+			self.unreadCountTotal = [StoreCoordinator unreadCountForIndexPathString:nil];
+			[self updateBarIcon];
+		});
+	}
 }

 /// Update menu bar icon and text according to unread count and user preferences.
@@ -117,23 +126,38 @@
 @param notify Notification object contains the unread count difference to the current count. May be negative.
 */
 - (void)unreadCountChanged:(NSNotification*)notify {
-	self.unreadCountTotal += [[notify object] intValue];
+	self.unreadCountTotal += [[notify object] integerValue];
 	[self updateBarIcon];
 }

 /// Callback method fired when feeds have been updated in the background.
 - (void)feedUpdated:(NSNotification*)notify {
+	[self updateFeed:notify.object updateIconOnly:NO];
+}
+
+- (void)feedIconUpdated:(NSNotification*)notify {
+	[self updateFeed:notify.object updateIconOnly:YES];
+}
+
+
+#pragma mark - Rebuild menu after background feed update
+
+
+/**
+ Use this method to update a single menu item and all ancestors unread count.
+ If the menu isn't currently open, nothing will happen.
+ 
+ @param oid @c NSManagedObjectID must be a @c Feed instance object id.
+ */
+- (void)updateFeed:(NSManagedObjectID*)oid updateIconOnly:(BOOL)flag {
 	if (self.barItem.menu.numberOfItems > 0) {
 		// update items only if menu is already open (e.g., during background update)
 		NSManagedObjectContext *moc = [StoreCoordinator createChildContext];
-		for (NSManagedObjectID *oid in notify.object) {
-			Feed *feed = [moc objectWithID:oid];
-			if (!feed) continue;
+		Feed *feed = [moc objectWithID:oid];
+		if ([feed isKindOfClass:[Feed class]]) {
 			NSMenu *menu = [self fixUnreadCountForSubmenus:feed];
-			if (!menu || menu.numberOfItems > 0)
-				[self rebuiltFeedArticle:feed inMenu:menu]; // deepest menu level, feed items
+			if (!flag) [self rebuiltFeedArticle:feed inMenu:menu]; // deepest menu level, feed items
 		}
-		[self.barItem.menu autoEnableMenuHeader:(self.unreadCountTotal > 0)]; // once per multi-feed update
 		[moc reset];
 	}
 }
@@ -145,18 +169,27 @@
 */
 - (nullable NSMenu*)fixUnreadCountForSubmenus:(Feed*)feed {
 	NSMenu *menu = self.barItem.menu;
+	[menu autoEnableMenuHeader:(self.unreadCountTotal > 0)];
 	for (FeedGroup *parent in [feed.group allParents]) {
-		NSInteger offset = [menu feedDataOffset];
-		NSMenuItem *item = [menu itemAtIndex:offset + parent.sortIndex];
+		NSInteger itemIndex = [menu feedDataOffset] + parent.sortIndex;
+		NSMenuItem *item = [menu itemAtIndex:itemIndex];
 		NSInteger unread = [item setTitleAndUnreadCount:parent];
 		menu = item.submenu;
+		
+		if (parent == feed.group) {
+			// Always set icon. Will flip warning icon to default icon if article count changes.
+			item.image = [feed iconImage16];
+			item.enabled = (feed.articles.count > 0);
+			return menu;
+		}
+		
 		if (!menu || menu.numberOfItems == 0)
 			return nil;
 		if (unread == 0) // if != 0 then 'setTitleAndUnreadCount' was successful (UserPrefs visible)
 			unread = [menu coreDataUnreadCount];
-		[menu autoEnableMenuHeader:(unread > 0)]; // of submenu (including: feed items menu)
+		[menu autoEnableMenuHeader:(unread > 0)]; // of submenu but not articles menu (will be rebuild anyway)
 	}
-	return menu;
+	return nil;
 }

 /**
@@ -166,6 +199,8 @@
 @param menu Deepest menu level which contains only feed items.
 */
 - (void)rebuiltFeedArticle:(Feed*)feed inMenu:(NSMenu*)menu {
+	if (!menu || menu.numberOfItems == 0) // not opened yet
+		return;
 	if (self.currentOpenMenu != menu) {
 		// if the menu isn't open, re-create it dynamically instead
 		menu.itemArray.firstObject.parentItem.submenu = [menu cleanInstanceCopy];
@@ -360,6 +395,7 @@
 Called when user clicks on 'Update all feeds' in the main menu (only).
 */
 - (void)updateAllFeeds:(NSMenuItem*)sender {
+	[self asyncReloadUnreadCountAndUpdateBarIcon:nil];
 	[FeedDownload forceUpdateAllFeeds];
 }

--- a/baRSS/StoreCoordinator.h
+++ b/baRSS/StoreCoordinator.h
@@ -37,8 +37,9 @@
 + (NSInteger)numberRootItemsInContext:(NSManagedObjectContext*)moc;
 + (NSArray<FeedGroup*>*)sortedListOfRootObjectsInContext:(NSManagedObjectContext*)moc;
 // Restore sound state
-+ (void)deleteUnreferencedFeeds;
-+ (void)restoreFeedCountsAndIndexPaths:(NSArray<NSManagedObjectID*>*)list;
+ (NSUInteger)deleteAllGroups;
+ (NSUInteger)deleteUnreferenced;
+ (void)restoreFeedCountsAndIndexPaths;
 + (NSArray<Feed*>*)listOfFeedsMissingArticlesInContext:(NSManagedObjectContext*)moc;
 + (NSArray<Feed*>*)listOfFeedsMissingIconsInContext:(NSManagedObjectContext*)moc;
@end
--- a/baRSS/StoreCoordinator.m
+++ b/baRSS/StoreCoordinator.m
@@ -24,8 +24,6 @@
 #import "AppHook.h"
 #import "Feed+Ext.h"

-#import <RSXML/RSXML.h>
-
@implementation StoreCoordinator

 #pragma mark - Managing contexts
@@ -40,7 +38,7 @@
 	NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
 	[context setParentContext:[self getMainContext]];
 	context.undoManager = nil;
-	context.automaticallyMergesChangesFromParent = YES;
+	//context.automaticallyMergesChangesFromParent = YES;
 	return context;
 }

@@ -178,46 +176,64 @@
 #pragma mark - Restore Sound State

 /**
- Delete all @c Feed items where @c group @c = @c NULL.
+ Perform batch delete on entities of type @c entity where @c column @c IS @c NULL. If @c column is @c nil, delete all rows.
 */
-+ (void)deleteUnreferencedFeeds {
-	NSManagedObjectContext *moc = [self getMainContext];
-	NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName: Feed.entity.name];
-	fr.predicate = [NSPredicate predicateWithFormat:@"group = NULL"];
+ (NSUInteger)batchDelete:(NSEntityDescription*)entity nullAttribute:(NSString*)column inContext:(NSManagedObjectContext*)moc {
+	NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName: entity.name];
+	if (column && column.length > 0) {
+		// double nested string, otherwise column is not interpreted as such.
+		// using @count here to also find items where foreign key is set but referencing a non-existing object.
+		fr.predicate = [NSPredicate predicateWithFormat:[NSString stringWithFormat:@"count(%@) == 0", column]];
+	}
 	NSBatchDeleteRequest *bdr = [[NSBatchDeleteRequest alloc] initWithFetchRequest:fr];
+	bdr.resultType = NSBatchDeleteResultTypeCount;
 	NSError *err;
-	[moc executeRequest:bdr error:&err];
+	NSBatchDeleteResult *lol = [moc executeRequest:bdr error:&err];
 	if (err) NSLog(@"%@", err);
+	return [lol.result unsignedIntegerValue];
 }

 /**
- Iterate over all @c Feed and re-calculate @c unreadCount, @c articleCount and @c indexPath.
- Restore will happend on the main context.
- 
- @param list A list of @c Feed objectIDs. Acts like a filter, if @c nil performs a fetch on all feed items.
+ Delete all @c FeedGroup items.
 */
-+ (void)restoreFeedCountsAndIndexPaths:(NSArray<NSManagedObjectID*>*)list {
+ (NSUInteger)deleteAllGroups {
 	NSManagedObjectContext *moc = [self getMainContext];
-	if (!list) {
-		NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName: Feed.entity.name];
-		[fr setResultType:NSManagedObjectIDResultType];
-		list = [self fetchAllRows:fr inContext:moc];
+	NSUInteger deleted = [self batchDelete:FeedGroup.entity nullAttribute:nil inContext:moc];
+	[self saveContext:moc andParent:YES];
+	return deleted;
+}
+
+/**
+ Delete all @c Feed items where @c group @c = @c NULL and all @c FeedMeta, @c FeedIcon, @c FeedArticle where @c feed @c = @c NULL.
+ */
+ (NSUInteger)deleteUnreferenced {
+	NSUInteger deleted = 0;
+	NSManagedObjectContext *moc = [self getMainContext];
+	deleted += [self batchDelete:Feed.entity nullAttribute:@"group" inContext:moc];
+	deleted += [self batchDelete:FeedMeta.entity nullAttribute:@"feed" inContext:moc];
+	deleted += [self batchDelete:FeedIcon.entity nullAttribute:@"feed" inContext:moc];
+	deleted += [self batchDelete:FeedArticle.entity nullAttribute:@"feed" inContext:moc];
+	[self saveContext:moc andParent:YES];
+	return deleted;
+}
+
+/**
+ Iterate over all @c Feed and re-calculate @c unreadCount and @c indexPath.
+ */
+ (void)restoreFeedCountsAndIndexPaths {
+	NSManagedObjectContext *moc = [self getMainContext];
+	NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName: Feed.entity.name];
+	for (Feed *f in [self fetchAllRows:fr inContext:moc]) {
+		[f calculateAndSetUnreadCount];
+		[f calculateAndSetIndexPathString];
 	}
-	[moc performBlock:^{
-		for (NSManagedObjectID *moi in list) {
-			Feed *f = [moc objectWithID:moi];
-			if ([f isKindOfClass:[Feed class]])
-				[f resetArticleCountAndIndexPathString];
-		}
-		[self saveContext:moc andParent:YES];
-	}];
+	[self saveContext:moc andParent:YES];
 }

 /// @return All @c Feed items where @c articles.count @c == @c 0
 + (NSArray<Feed*>*)listOfFeedsMissingArticlesInContext:(NSManagedObjectContext*)moc {
 	NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName: Feed.entity.name];
-	// More accurate but with subquery on FeedArticle: "count(articles) == 0"
-	fr.predicate = [NSPredicate predicateWithFormat:@"articleCount == 0"];
+	fr.predicate = [NSPredicate predicateWithFormat:@"articles.@count == 0"];
 	return [self fetchAllRows:fr inContext:moc];
 }