Merge pull request #88 from vkovtash/feature/namespaces

Namespaces implementation

Author: mallorypaine

FastImageCache/FICImageCache.h

@@ -24,6 +24,14 @@ typedef void (^FICImageRequestCompletionBlock)(UIImage *sourceImage);
  */
 @interface FICImageCache : NSObject
 
+/**
+ The namespace of the image cache.
+ 
+ @discussion Namespace is responsible for isolation of dirrerent image cache instances on file system level. Namespace should be unique across application.
+ */
+
+@property (readonly, nonatomic) NSString *nameSpace;
+
 ///----------------------------
 /// @name Managing the Delegate
 ///----------------------------
@@ -36,6 +44,25 @@ typedef void (^FICImageRequestCompletionBlock)(UIImage *sourceImage);
  */
 @property (nonatomic, weak) id <FICImageCacheDelegate> delegate;
 
+///---------------------------------------
+/// @name Creating Image Cache instances
+///---------------------------------------
+
+/**
+ Returns new image cache.
+ 
+ @return A new instance of `FICImageCache`.
+ 
+ @param nameSpace The namespace that uniquely identifies current image cahce entity. If no nameSpace given, default namespace will be used.
+ 
+ @note Fast Image Cache can either be used as a singleton for convenience or can exist as multiple instances. 
+ However, all instances of `FICImageCache` will make use same dispatch queue. To separate location on disk for storing image tables namespaces are used.
+ 
+ @see [FICImageCache dispatchQueue]
+ */
+
+- (instancetype)initWithNameSpace:(NSString *)nameSpace;
+
 ///---------------------------------------
 /// @name Accessing the Shared Image Cache
 ///---------------------------------------
@@ -45,8 +72,7 @@ typedef void (^FICImageRequestCompletionBlock)(UIImage *sourceImage);
  
  @return A shared instance of `FICImageCache`.
  
- @note Fast Image Cache can either be used as a singleton for convenience or can exist as multiple instances. However, all instances of `FICImageCache` will make use of
- shared resources, such as the same dispatch queue and the same location on disk for storing image tables.
+ @note Shared instance always binded to default namespace.
  
  @see [FICImageCache dispatchQueue]
  */

FastImageCache/FICImageCache.m

@@ -78,13 +78,17 @@ + (dispatch_queue_t)dispatchQueue {
     return __imageCacheDispatchQueue;
 }
 
-- (id)init {
+- (instancetype)init {
+    return [self initWithNameSpace:@"FICDefaultNamespace"];
+}
+
+- (instancetype)initWithNameSpace:(NSString *)nameSpace {
     self = [super init];
-    
-    if (self != nil) {
+    if (self) {
         _formats = [[NSMutableDictionary alloc] init];
         _imageTables = [[NSMutableDictionary alloc] init];
         _requests = [[NSMutableDictionary alloc] init];
+        _nameSpace = nameSpace;
     }
     return self;
 }
@@ -114,6 +118,9 @@ - (void)setFormats:(NSArray *)formats {
         // Remove any extraneous files in the image tables directory
         NSFileManager *fileManager = [NSFileManager defaultManager];
         NSString *directoryPath = [FICImageTable directoryPath];
+        if (self.nameSpace) {
+            directoryPath = [directoryPath stringByAppendingPathComponent:self.nameSpace];
+        }
         NSArray *fileNames = [fileManager contentsOfDirectoryAtPath:directoryPath error:nil];
         for (NSString *fileName in fileNames) {
             if ([imageTableFiles containsObject:fileName] == NO) {

FastImageCache/FICImageTable.m

@@ -81,18 +81,26 @@ @implementation FICImageTable
 
 - (NSString *)tableFilePath {
     NSString *tableFilePath = [[_imageFormat name] stringByAppendingPathExtension:FICImageTableFileExtension];
-    tableFilePath = [[FICImageTable directoryPath] stringByAppendingPathComponent:tableFilePath];
+    tableFilePath = [[self directoryPath] stringByAppendingPathComponent:tableFilePath];
 
     return tableFilePath;
 }
 
 - (NSString *)metadataFilePath {
     NSString *metadataFilePath = [[_imageFormat name] stringByAppendingPathExtension:FICImageTableMetadataFileExtension];
-    metadataFilePath = [[FICImageTable directoryPath] stringByAppendingPathComponent:metadataFilePath];
+    metadataFilePath = [[self directoryPath] stringByAppendingPathComponent:metadataFilePath];
 
     return metadataFilePath;
 }
 
+- (NSString *) directoryPath {
+    NSString *directoryPath = [FICImageTable directoryPath];
+    if (self.imageCache.nameSpace) {
+        directoryPath = [directoryPath stringByAppendingPathComponent:self.imageCache.nameSpace];
+    }
+    return directoryPath;
+}
+
 #pragma mark - Class-Level Definitions
 
 + (int)pageSize {
@@ -167,7 +175,15 @@ - (instancetype)initWithFormat:(FICImageFormat *)imageFormat imageCache:(FICImag
 
         [self _loadMetadata];
 
+        NSString *directoryPath = [self directoryPath];
+        
         NSFileManager *fileManager = [[NSFileManager alloc] init];
+        
+        BOOL isDirectory;
+        if (self.imageCache.nameSpace && ![fileManager fileExistsAtPath:directoryPath isDirectory:&isDirectory]) {
+            [fileManager createDirectoryAtPath:directoryPath withIntermediateDirectories:YES attributes:nil error:nil];
+        }
+        
         if ([fileManager fileExistsAtPath:_filePath] == NO) {
             NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
             [attributes setValue:[_imageFormat protectionModeString] forKeyPath:NSFileProtectionKey];
@@ -686,7 +702,7 @@ - (void)saveMetadata {
 }
 
 - (void)_loadMetadata {
-    NSString *metadataFilePath = [[_filePath stringByDeletingPathExtension] stringByAppendingPathExtension:FICImageTableMetadataFileExtension];
+    NSString *metadataFilePath = [self metadataFilePath];
     NSData *metadataData = [NSData dataWithContentsOfURL:[NSURL fileURLWithPath:metadataFilePath] options:NSDataReadingMappedAlways error:NULL];
     if (metadataData != nil) {
         NSDictionary *metadataDictionary = (NSDictionary *)[NSPropertyListSerialization propertyListWithData:metadataData options:0 format:NULL error:NULL];