Performance improvements on groups

Example/WPMediaPicker/AppDelegate.m

@@ -35,6 +35,7 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
     UIColor *cellBackgroundColor = [UIColor colorWithRed:243/255.0f green:246/255.0f blue:248/255.0f alpha:1.0f];
     [[WPMediaCollectionViewCell appearanceWhenContainedIn:[WPMediaPickerViewController class],nil] setBackgroundColor:cellBackgroundColor];
     [[WPMediaCollectionViewCell appearanceWhenContainedIn:[WPInputMediaPickerViewController class],nil] setBackgroundColor:cellBackgroundColor];
+    [[UIImageView appearanceWhenContainedIn:[WPMediaGroupTableViewCell class],nil] setBackgroundColor:cellBackgroundColor];
 
     //Configure color for activity indicator while loading media collection
     [[UIActivityIndicatorView appearanceWhenContainedIn:[WPMediaPickerViewController class],nil] setColor:[UIColor grayColor]];

Pod/Classes/WPMediaCollectionDataSource.h

@@ -21,13 +21,21 @@ typedef NS_ENUM(NSInteger, WPMediaPickerErrorCode){
 - (NSUInteger)to;
 @end
 
+typedef NS_ENUM(NSInteger, WPMediaLoadOptions){
+    WPMediaLoadOptionsGroups,
+    WPMediaLoadOptionsAssets,
+    WPMediaLoadOptionsGroupsAndAssets
+};
+
+
 @protocol WPMediaAsset;
 
 typedef void (^WPMediaChangesBlock)(BOOL incrementalChanges, NSIndexSet *removed, NSIndexSet *inserted, NSIndexSet *changed, NSArray<id<WPMediaMove>> *moves);
 typedef void (^WPMediaSuccessBlock)();
 typedef void (^WPMediaFailureBlock)(NSError *error);
 typedef void (^WPMediaAddedBlock)(id<WPMediaAsset> media, NSError *error);
 typedef void (^WPMediaImageBlock)(UIImage *result, NSError *error);
+typedef void (^WPMediaCountBlock)(NSInteger result, NSError *error);
 typedef void (^WPMediaAssetBlock)(AVAsset *asset, NSError *error);
 typedef int32_t WPMediaRequestID;
 
@@ -68,11 +76,13 @@ typedef int32_t WPMediaRequestID;
 - (NSString *)identifier;
 
 /**
- *  The numbers of assets that exist in the group
- *
- *  @return The numbers of assets that exist in the group
+ The numbers of assets that exist in the group of a certain mediaType
+
+ @param mediaType the asset type to count
+ @param completionHandler a block that is executed when the real number of assets is know.
+ @return return an estimation of the current number of assets, if no estimate is known return NSNotFound
  */
-- (NSInteger)numberOfAssetsOfType:(WPMediaType)mediaType;
+- (NSInteger)numberOfAssetsOfType:(WPMediaType)mediaType completionHandler:(WPMediaCountBlock)completionHandler;
 
 @end
 
@@ -250,16 +260,14 @@ typedef int32_t WPMediaRequestID;
  *  Asks the data source to reload the data available of the media library. This should be invoked after changing the 
  *  current active group or if a change is detected.
  *
+ *  @param options specifiy what type of data to load
  *  @param successBlock a block that is invoked when the data is loaded with success.
  *  @param failureBlock a block that is invoked when the are is any kind of error when loading the data.
  */
-- (void)loadDataWithSuccess:(WPMediaSuccessBlock)successBlock
+- (void)loadDataWithOptions:(WPMediaLoadOptions)options
+                    success:(WPMediaSuccessBlock)successBlock
                     failure:(WPMediaFailureBlock)failureBlock;
 
-- (void)loadGroupDataWithSuccess:(WPMediaSuccessBlock)successBlock
-                         failure:(WPMediaFailureBlock)failureBlock;
-
-
 /**
  *  Requests to the data source to add an image to the library.
  *

Pod/Classes/WPMediaGroupPickerViewController.m

@@ -42,16 +42,14 @@ - (void)viewDidLoad
     self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelPicker:)];
     __weak __typeof__(self) weakSelf = self;
     self.changesObserver = [self.dataSource registerChangeObserverBlock:^(BOOL incrementalChanges, NSIndexSet *deleted, NSIndexSet *inserted, NSIndexSet *reload, NSArray *moves) {
-            dispatch_async(dispatch_get_main_queue(), ^{
-                [weakSelf loadData];
-            });
+            [weakSelf loadData];            
         }];
     [self loadData];
 }
 
 - (void)loadData
 {
-    [self.dataSource loadGroupDataWithSuccess:^{
+    [self.dataSource loadDataWithOptions:WPMediaLoadOptionsGroups success:^{
         dispatch_async(dispatch_get_main_queue(), ^{
             [self.tableView reloadData];
         });
@@ -135,7 +133,11 @@ - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(N
     }];
     cell.tag = requestKey;
     cell.titleLabel.text = [group name];
-    NSInteger numberOfAssets = [group numberOfAssetsOfType:[self.dataSource mediaTypeFilter]];
+    NSInteger numberOfAssets = [group numberOfAssetsOfType:[self.dataSource mediaTypeFilter] completionHandler:^(NSInteger result, NSError *error) {
+        dispatch_async(dispatch_get_main_queue(), ^{
+            cell.countLabel.text = [NSString stringWithFormat:@"%ld", (long)result];            
+        });
+    }];
     if (numberOfAssets != NSNotFound) {
         cell.countLabel.text = [NSString stringWithFormat:@"%ld", (long)numberOfAssets];
     } else {

Pod/Classes/WPMediaPickerViewController.m

@@ -296,7 +296,7 @@ - (void)refreshDataAnimated:(BOOL)animated
 
     __weak __typeof__(self) weakSelf = self;
 
-    [self.dataSource loadDataWithSuccess:^{
+    [self.dataSource loadDataWithOptions:WPMediaLoadOptionsAssets success:^{
         __typeof__(self) strongSelf = weakSelf;
         BOOL refreshGroupFirstTime = strongSelf.refreshGroupFirstTime;
         strongSelf.refreshGroupFirstTime = NO;

Pod/Classes/WPPHAssetDataSource.m

@@ -101,7 +101,8 @@ - (void)photoLibraryDidChange:(PHChange *)changeInstance
     });
 }
 
-- (void)loadDataWithSuccess:(WPMediaSuccessBlock)successBlock
+- (void)loadDataWithOptions:(WPMediaLoadOptions)options
+                    success:(WPMediaSuccessBlock)successBlock
                     failure:(WPMediaFailureBlock)failureBlock
 {
     PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
@@ -118,51 +119,31 @@ - (void)loadDataWithSuccess:(WPMediaSuccessBlock)successBlock
         case PHAuthorizationStatusNotDetermined:
         {
             [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
-                [self loadDataWithSuccess:successBlock failure:failureBlock];
+                [self loadDataWithOptions:options success:successBlock failure:failureBlock];
             }];
         }
         case PHAuthorizationStatusAuthorized: {
-            dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0), ^{
+            dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
                 if (self.activeAssetsCollection == nil) {
                     self.activeAssetsCollection = [[PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum
                                                                                             subtype:PHAssetCollectionSubtypeSmartAlbumUserLibrary
                                                                                             options:nil] firstObject];
                 }
-                if (self.refreshGroups) {
-                    [[[self class] sharedImageManager] stopCachingImagesForAllAssets];
-                    [self loadGroupsWithSuccess:^{
-                        self.refreshGroups = NO;
-                    } failure:nil];
+                switch (options) {
+                    case (WPMediaLoadOptionsGroups): {
+                        [self loadGroupsWithSuccess:successBlock failure:failureBlock];
+                        return;
+                    }
+                    case (WPMediaLoadOptionsAssets): {
+                        [self loadAssetsWithSuccess:successBlock failure:failureBlock];
+                        return;
+                    }
+                    case (WPMediaLoadOptionsGroupsAndAssets): {
+                        [self loadGroupsWithSuccess:^{
+                            [self loadAssetsWithSuccess:successBlock failure:failureBlock];
+                        } failure:failureBlock];
+                    }
                 }
-                [self loadAssetsWithSuccess:successBlock failure:failureBlock];
-            });
-        }
-    }
-}
-
-- (void)loadGroupDataWithSuccess:(WPMediaSuccessBlock)successBlock
-                         failure:(WPMediaFailureBlock)failureBlock
-{
-    PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
-    switch (status) {
-        case PHAuthorizationStatusRestricted:
-        case PHAuthorizationStatusDenied:
-        {
-            if (failureBlock) {
-                NSError *error = [NSError errorWithDomain:WPMediaPickerErrorDomain code:WPMediaErrorCodePermissionsFailed userInfo:nil];
-                failureBlock(error);
-            }
-            return;
-        }
-        case PHAuthorizationStatusNotDetermined:
-        {
-            [PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
-                [self loadGroupDataWithSuccess:successBlock failure:failureBlock];
-            }];
-        }
-        case PHAuthorizationStatusAuthorized: {
-            dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INTERACTIVE, 0), ^{
-                [self loadGroupsWithSuccess:successBlock failure:failureBlock];
             });
         }
     }
@@ -190,28 +171,21 @@ - (NSArray *)smartAlbumsToShow {
 - (void)loadGroupsWithSuccess:(WPMediaSuccessBlock)successBlock
                       failure:(WPMediaFailureBlock)failureBlock
 {
-    PHFetchOptions *fetchOptions = [PHFetchOptions new];
-    fetchOptions.predicate = [[self class] predicateForFilterMediaType:self.mediaTypeFilter];
     NSMutableArray *collectionsArray=[NSMutableArray array];
     for (NSNumber *subType in [self smartAlbumsToShow]) {
         PHFetchResult * smartAlbum = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum
                                                                            subtype:[subType intValue]
                                                                            options:nil];
         PHAssetCollection *collection = (PHAssetCollection *)smartAlbum.firstObject;
-        if ([PHAsset fetchAssetsInAssetCollection:collection options:fetchOptions].count > 0 || [subType intValue] == PHAssetCollectionSubtypeSmartAlbumUserLibrary){
-            [collectionsArray addObjectsFromArray:[smartAlbum objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, smartAlbum.count)]]];
-        }
+        [collectionsArray addObject:collection];
     }
 
     self.albums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
                                                            subtype:PHAssetCollectionSubtypeAny
                                                            options:nil];
 
-    [self.albums enumerateObjectsUsingBlock:^(PHAssetCollection *collection, NSUInteger index, BOOL *stop){
-        if ([PHAsset fetchAssetsInAssetCollection:collection options:fetchOptions].count > 0) {
-            [collectionsArray addObject:collection];
-        }
-    }];
+    [collectionsArray addObjectsFromArray:[self.albums objectsAtIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, self.albums.count)]]];
+
 
     PHCollectionList *allAlbums = [PHCollectionList transientCollectionListWithCollections:collectionsArray title:@"Root"];
     self.assetsCollections = [PHAssetCollection fetchCollectionsInCollectionList:allAlbums options:nil];
@@ -232,6 +206,10 @@ - (void)loadGroupsWithSuccess:(WPMediaSuccessBlock)successBlock
         }
 
     }
+
+    self.albums = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeAlbum
+                                                           subtype:PHAssetCollectionSubtypeAny
+                                                           options:nil];
 }
 
 + (NSPredicate *)predicateForFilterMediaType:(WPMediaType)mediaType
@@ -558,6 +536,7 @@ @interface PHAssetCollectionForWPMediaGroup()
 @property(nonatomic, strong) PHAsset *posterAsset;
 @property(nonatomic, assign) WPMediaType mediaType;
 @property(nonatomic, strong) PHFetchResult *fetchResult;
+@property(nonatomic, strong) PHFetchResult *posterAssetFetchResult;
 
 @end
 
@@ -584,7 +563,10 @@ - (NSString *)name
 
 - (WPMediaRequestID)imageWithSize:(CGSize)size completionHandler:(WPMediaImageBlock)completionHandler
 {
-    return [self.posterAsset imageWithSize:size completionHandler:completionHandler];
+    dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
+        [self.posterAsset imageWithSize:size completionHandler:completionHandler];
+    });
+    return 0;
 }
 
 - (void)cancelImageRequest:(WPMediaRequestID)requestID
@@ -602,18 +584,13 @@ - (NSString *)identifier
     return [self.collection localIdentifier];
 }
 
-- (NSInteger)numberOfAssetsOfType:(WPMediaType)mediaType
+- (NSInteger)numberOfAssetsOfType:(WPMediaType)mediaType completionHandler:(WPMediaCountBlock)completionHandler
 {
-    NSInteger count = self.collection.estimatedAssetCount;
-    if (count != NSNotFound) {
-        return count;
-    }
-
-    if (self.assetCount == NSNotFound) {
+    dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
         self.assetCount = [self.fetchResult count];
-    }
-
-    return self.assetCount;
+        completionHandler(self.assetCount, nil);
+    });
+    return self.collection.estimatedAssetCount;
 }
 
 - (PHFetchResult *)fetchResult {
@@ -626,9 +603,20 @@ - (PHFetchResult *)fetchResult {
     return _fetchResult;
 }
 
+- (PHFetchResult *)posterAssetFetchResult {
+    if (!_posterAssetFetchResult) {
+        PHFetchOptions *fetchOptions = [PHFetchOptions new];
+        fetchOptions.fetchLimit = 1;
+        fetchOptions.predicate = [WPPHAssetDataSource predicateForFilterMediaType:_mediaType];
+        _posterAssetFetchResult = [PHAsset fetchKeyAssetsInAssetCollection:self.collection options:fetchOptions];
+    }
+
+    return _posterAssetFetchResult;
+}
+
 - (PHAsset *)posterAsset {
     if (!_posterAsset) {
-        _posterAsset = [[self fetchResult] lastObject];
+        _posterAsset = [[self posterAssetFetchResult] firstObject];
     }
 
     return _posterAsset;