Extract thumbnails cache as a separate class

AspenProject/VLCPlaylistGridView.m

@@ -10,10 +10,8 @@
 
 #import "VLCPlaylistGridView.h"
 #import "VLCLinearProgressIndicator.h"
-#import "VLCAppDelegate.h"
 #import "AQGridView.h"
-
-#define MAX_CACHE_SIZE 27 // three times the number of items shown on iPad
+#import "VLCThumbnailsCache.h"
 
 @interface VLCPlaylistGridView (Hack)
 @property (nonatomic, retain) NSString *reuseIdentifier;
@@ -99,7 +97,7 @@
         [self configureForMLFile:mediaObject];
 
         if (([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) && !mediaObject.isAlbumTrack) {
-            self.thumbnailView.image = [self thumbnailForMediaFile:mediaObject];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:mediaObject];
         }
 
     } else if ([self.mediaObject isKindOfClass:[MLAlbum class]]) {
@@ -116,7 +114,7 @@
 
         if ([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) {
             MLFile *anyFileFromAnyEpisode = [mediaObject.episodes.anyObject files].anyObject;
-            self.thumbnailView.image = [self thumbnailForMediaFile:anyFileFromAnyEpisode];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:anyFileFromAnyEpisode];
         }
     } else if ([self.mediaObject isKindOfClass:[MLShowEpisode class]]) {
         MLShowEpisode *mediaObject = (MLShowEpisode *)self.mediaObject;
@@ -124,7 +122,7 @@
 
         if ([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) {
             MLFile *anyFileFromEpisode = mediaObject.files.anyObject;
-            self.thumbnailView.image = [self thumbnailForMediaFile:anyFileFromEpisode];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:anyFileFromEpisode];
         }
     }
 
@@ -240,42 +238,4 @@
     self.mediaIsUnreadView.hidden = !mediaFile.unread.intValue;
 }
 
-// Can be extracted outside of VLCPlaylistGridView
-- (UIImage *)thumbnailForMediaFile:(MLFile *)mediaFile {
-    if (mediaFile == nil || mediaFile.objectID == nil)
-        return nil;
-
-    static NSMutableArray *_thumbnailCacheIndex;
-    static NSMutableDictionary *_thumbnailCache;
-    if (!_thumbnailCache)
-        _thumbnailCache = [[NSMutableDictionary alloc] initWithCapacity:MAX_CACHE_SIZE];
-    if (!_thumbnailCacheIndex)
-        _thumbnailCacheIndex = [[NSMutableArray alloc] initWithCapacity:MAX_CACHE_SIZE];
-
-    NSManagedObjectID *objID = mediaFile.objectID;
-    UIImage *displayedImage = nil;
-    if ([_thumbnailCacheIndex containsObject:objID]) {
-        [_thumbnailCacheIndex removeObject:objID];
-        [_thumbnailCacheIndex insertObject:objID atIndex:0];
-        displayedImage = [_thumbnailCache objectForKey:objID];
-        if (!displayedImage && mediaFile.computedThumbnail) {
-            displayedImage = mediaFile.computedThumbnail;
-            [_thumbnailCache setObject:displayedImage forKey:objID];
-        }
-    } else {
-        if (_thumbnailCacheIndex.count >= MAX_CACHE_SIZE) {
-            [_thumbnailCache removeObjectForKey:[_thumbnailCacheIndex lastObject]];
-            [_thumbnailCacheIndex removeLastObject];
-        }
-        displayedImage = mediaFile.computedThumbnail;
-
-        if (displayedImage) {
-            [_thumbnailCache setObject:displayedImage forKey:objID];
-            [_thumbnailCacheIndex insertObject:objID atIndex:0];
-        }
-    }
-
-    return displayedImage;
-}
-
 @end

AspenProject/VLCPlaylistTableViewCell.m

@@ -10,10 +10,9 @@
 
 #import "VLCPlaylistTableViewCell.h"
 #import "VLCLinearProgressIndicator.h"
+#import "VLCThumbnailsCache.h"
 #import <MediaLibraryKit/MLAlbum.h>
 
-#define MAX_CACHE_SIZE 21 // three times the number of items shown on iPhone 5
-
 @implementation VLCPlaylistTableViewCell
 
 + (VLCPlaylistTableViewCell *)cellWithReuseIdentifier:(NSString *)ident
@@ -88,7 +87,7 @@
         [self configureForMLFile:mediaObject];
 
         if (([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) && !mediaObject.isAlbumTrack) {
-            self.thumbnailView.image = [self thumbnailForMediaFile:mediaObject];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:mediaObject];
         }
 
     } else if ([self.mediaObject isKindOfClass:[MLAlbum class]]) {
@@ -105,7 +104,7 @@
 
         if ([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) {
             MLFile *anyFileFromAnyEpisode = [mediaObject.episodes.anyObject files].anyObject;
-            self.thumbnailView.image = [self thumbnailForMediaFile:anyFileFromAnyEpisode];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:anyFileFromAnyEpisode];
         }
 
     } else if ([self.mediaObject isKindOfClass:[MLShowEpisode class]]) {
@@ -114,7 +113,7 @@
 
         if ([keyPath isEqualToString:@"computedThumbnail"] || !keyPath) {
             MLFile *anyFileFromEpisode = mediaObject.files.anyObject;
-            self.thumbnailView.image = [self thumbnailForMediaFile:anyFileFromEpisode];
+            self.thumbnailView.image = [VLCThumbnailsCache thumbnailForMediaFile:anyFileFromEpisode];
         }
     }
 
@@ -219,44 +218,4 @@
     self.mediaIsUnreadView.hidden = !mediaFile.unread.intValue;
 }
 
-#pragma mark - thumbnails cache
-
-// Can be extracted outside of VLCPlaylistTableViewCell
-- (UIImage *)thumbnailForMediaFile:(MLFile *)mediaFile {
-    if (mediaFile == nil || mediaFile.objectID == nil)
-        return nil;
-
-    static NSMutableArray *_thumbnailCacheIndex;
-    static NSMutableDictionary *_thumbnailCache;
-    if (!_thumbnailCache)
-        _thumbnailCache = [[NSMutableDictionary alloc] initWithCapacity:MAX_CACHE_SIZE];
-    if (!_thumbnailCacheIndex)
-        _thumbnailCacheIndex = [[NSMutableArray alloc] initWithCapacity:MAX_CACHE_SIZE];
-
-    NSManagedObjectID *objID = mediaFile.objectID;
-    UIImage *displayedImage = nil;
-    if ([_thumbnailCacheIndex containsObject:objID]) {
-        [_thumbnailCacheIndex removeObject:objID];
-        [_thumbnailCacheIndex insertObject:objID atIndex:0];
-        displayedImage = [_thumbnailCache objectForKey:objID];
-        if (!displayedImage && mediaFile.computedThumbnail) {
-            displayedImage = mediaFile.computedThumbnail;
-            [_thumbnailCache setObject:displayedImage forKey:objID];
-        }
-    } else {
-        if (_thumbnailCacheIndex.count >= MAX_CACHE_SIZE) {
-            [_thumbnailCache removeObjectForKey:[_thumbnailCacheIndex lastObject]];
-            [_thumbnailCacheIndex removeLastObject];
-        }
-        displayedImage = mediaFile.computedThumbnail;
-
-        if (displayedImage) {
-            [_thumbnailCache setObject:displayedImage forKey:objID];
-            [_thumbnailCacheIndex insertObject:objID atIndex:0];
-        }
-    }
-
-    return displayedImage;
-}
-
 @end

AspenProject/VLCThumbnailsCache.h

@@ -0,0 +1,17 @@
+//
+//  VLCThumbnailsCache.h
+//  VLC for iOS
+//
+//  Created by Gleb on 9/13/13.
+//  Copyright (c) 2013 VideoLAN. All rights reserved.
+//
+//  Refer to the COPYING file of the official project for license.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface VLCThumbnailsCache : NSObject
+
++ (UIImage *)thumbnailForMediaFile:(MLFile *)mediaFile;
+
+@end

AspenProject/VLCThumbnailsCache.m

@@ -0,0 +1,63 @@
+//
+//  VLCThumbnailsCache.m
+//  VLC for iOS
+//
+//  Created by Gleb on 9/13/13.
+//  Copyright (c) 2013 VideoLAN. All rights reserved.
+//
+//  Refer to the COPYING file of the official project for license.
+//
+
+#import "VLCThumbnailsCache.h"
+
+static NSInteger MaxCacheSize;
+static NSMutableArray *_thumbnailCacheIndex = nil;
+static NSMutableDictionary *_thumbnailCache = nil;
+
+@implementation VLCThumbnailsCache
+
+#define MAX_CACHE_SIZE_IPHONE 21  // three times the number of items shown on iPhone 5
+#define MAX_CACHE_SIZE_IPAD   27  // three times the number of items shown on iPad
+
++(void)initialize
+{
+    MaxCacheSize = (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)?
+                                MAX_CACHE_SIZE_IPAD: MAX_CACHE_SIZE_IPHONE;
+
+    // TODO Consider to use NSCache
+    _thumbnailCache = [[NSMutableDictionary alloc] initWithCapacity:MaxCacheSize];
+    _thumbnailCacheIndex = [[NSMutableArray alloc] initWithCapacity:MaxCacheSize];
+}
+
++ (UIImage *)thumbnailForMediaFile:(MLFile *)mediaFile
+{
+    if (mediaFile == nil || mediaFile.objectID == nil)
+        return nil;
+
+    NSManagedObjectID *objID = mediaFile.objectID;
+    UIImage *displayedImage = nil;
+    if ([_thumbnailCacheIndex containsObject:objID]) {
+        [_thumbnailCacheIndex removeObject:objID];
+        [_thumbnailCacheIndex insertObject:objID atIndex:0];
+        displayedImage = [_thumbnailCache objectForKey:objID];
+        if (!displayedImage && mediaFile.computedThumbnail) {
+            displayedImage = mediaFile.computedThumbnail;
+            [_thumbnailCache setObject:displayedImage forKey:objID];
+        }
+    } else {
+        if (_thumbnailCacheIndex.count >= MaxCacheSize) {
+            [_thumbnailCache removeObjectForKey:[_thumbnailCacheIndex lastObject]];
+            [_thumbnailCacheIndex removeLastObject];
+        }
+        displayedImage = mediaFile.computedThumbnail;
+
+        if (displayedImage) {
+            [_thumbnailCache setObject:displayedImage forKey:objID];
+            [_thumbnailCacheIndex insertObject:objID atIndex:0];
+        }
+    }
+
+    return displayedImage;
+}
+
+@end

VLC for iOS.xcodeproj/project.pbxproj

@@ -280,6 +280,7 @@
 		A7A0E9F9174BA66000162F25 /* papasscode_marker.png in Resources */ = {isa = PBXBuildFile; fileRef = A7A0E9F1174BA66000162F25 /* papasscode_marker.png */; };
 		A7A0E9FA174BA66000162F25 /* papasscode_marker@2x.png in Resources */ = {isa = PBXBuildFile; fileRef = A7A0E9F2174BA66000162F25 /* papasscode_marker@2x.png */; };
 		A7A0E9FB174BA66000162F25 /* PAPasscodeViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = A7A0E9F4174BA66000162F25 /* PAPasscodeViewController.m */; };
+		A7B5315F17E35B6E00EAE4B3 /* VLCThumbnailsCache.m in Sources */ = {isa = PBXBuildFile; fileRef = A7B5315E17E35B6E00EAE4B3 /* VLCThumbnailsCache.m */; };
 		A7C3025E175A53D400AD4388 /* NSString+SupportedMedia.m in Sources */ = {isa = PBXBuildFile; fileRef = A7C3025D175A53D400AD4388 /* NSString+SupportedMedia.m */; };
 		A7CB0DB11716F72600050CF3 /* PlayingExternally@2x~iphone.png in Resources */ = {isa = PBXBuildFile; fileRef = A7CB0DAD1716F72600050CF3 /* PlayingExternally@2x~iphone.png */; };
 		A7CB0DB21716F72600050CF3 /* PlayingExternally~iphone.png in Resources */ = {isa = PBXBuildFile; fileRef = A7CB0DAE1716F72600050CF3 /* PlayingExternally~iphone.png */; };
@@ -771,6 +772,8 @@
 		A7A0E9F2174BA66000162F25 /* papasscode_marker@2x.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "papasscode_marker@2x.png"; sourceTree = "<group>"; };
 		A7A0E9F3174BA66000162F25 /* PAPasscodeViewController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PAPasscodeViewController.h; sourceTree = "<group>"; };
 		A7A0E9F4174BA66000162F25 /* PAPasscodeViewController.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = PAPasscodeViewController.m; sourceTree = "<group>"; };
+		A7B5315D17E35B6E00EAE4B3 /* VLCThumbnailsCache.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = VLCThumbnailsCache.h; sourceTree = "<group>"; };
+		A7B5315E17E35B6E00EAE4B3 /* VLCThumbnailsCache.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = VLCThumbnailsCache.m; sourceTree = "<group>"; };
 		A7C3025C175A53D400AD4388 /* NSString+SupportedMedia.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSString+SupportedMedia.h"; sourceTree = "<group>"; };
 		A7C3025D175A53D400AD4388 /* NSString+SupportedMedia.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSString+SupportedMedia.m"; sourceTree = "<group>"; };
 		A7CB0DAD1716F72600050CF3 /* PlayingExternally@2x~iphone.png */ = {isa = PBXFileReference; lastKnownFileType = image.png; path = "PlayingExternally@2x~iphone.png"; sourceTree = "<group>"; };
@@ -1231,6 +1234,8 @@
 				7DA6209A170A0CE500643D11 /* VLCPlaylistTableViewCell.m */,
 				7D6B07F51716D45B003280C4 /* VLCPlaylistGridView.h */,
 				7D6B07F61716D45B003280C4 /* VLCPlaylistGridView.m */,
+				A7B5315D17E35B6E00EAE4B3 /* VLCThumbnailsCache.h */,
+				A7B5315E17E35B6E00EAE4B3 /* VLCThumbnailsCache.m */,
 			);
 			name = "Everything Playlist";
 			sourceTree = "<group>";
@@ -1989,6 +1994,7 @@
 				7D02B0D217B6BE850099030D /* VLCLocalServerFolderListViewController.m in Sources */,
 				7DC72D6317B7ED24008A26D0 /* WhiteRaccoon.m in Sources */,
 				7DC72D6917B820C9008A26D0 /* VLCNetworkLoginViewController.m in Sources */,
+				A7B5315F17E35B6E00EAE4B3 /* VLCThumbnailsCache.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};