allow override diskCachePath

@@ -65,6 +65,8 @@ typedef void(^SDWebImageCalculateSizeBlock)(NSUInteger fileCount, NSUInteger tot
  */
 - (id)initWithNamespace:(NSString *)ns;
 
+-(NSString *)makeDiskCachePath:(NSString*)fullNamespace;
+
 /**
  * Add a read-only cache path to search for images pre-cached by SDImageCache
  * Useful if you want to bundle pre-loaded images with your app

@@ -74,8 +74,7 @@ BOOL ImageDataHasPNGPreffix(NSData *data) {
         _memCache.name = fullNamespace;
 
         // Init the disk cache
-        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
-        _diskCachePath = [paths[0] stringByAppendingPathComponent:fullNamespace];
+        _diskCachePath = [self makeDiskCachePath:fullNamespace];
 
         dispatch_sync(_ioQueue, ^{
             _fileManager = [NSFileManager new];
@@ -144,6 +143,12 @@ BOOL ImageDataHasPNGPreffix(NSData *data) {
 
 #pragma mark ImageCache
 
+// Init the disk cache
+-(NSString *)makeDiskCachePath:(NSString*)fullNamespace{
+    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
+    return [paths[0] stringByAppendingPathComponent:fullNamespace];
+}
+
 - (void)storeImage:(UIImage *)image recalculateFromImage:(BOOL)recalculate imageData:(NSData *)imageData forKey:(NSString *)key toDisk:(BOOL)toDisk {
     if (!image || !key) {
         return;