Merge pull request #2299 from dreampiggy/feature_cache_namespace_prefix

Add the ability to custom the cache namespace prefix

SDWebImage/SDImageCache.m

@@ -59,7 +59,11 @@
                        diskCacheDirectory:(nonnull NSString *)directory
                                    config:(nullable SDImageCacheConfig *)config {
     if ((self = [super init])) {
-        NSString *fullNamespace = [@"com.hackemist.SDImageCache." stringByAppendingString:ns];
+        NSString *namespacePrefix = config.namespacePrefix;
+        if (!namespacePrefix) {
+            namespacePrefix = @"";
+        }
+        NSString *fullNamespace = [namespacePrefix stringByAppendingString:ns];
         
         // Create IO serial queue
         _ioQueue = dispatch_queue_create("com.hackemist.SDImageCache", DISPATCH_QUEUE_SERIAL);

SDWebImage/SDImageCacheConfig.h

@@ -72,6 +72,12 @@
  */
 @property (assign, nonatomic) NSUInteger maxMemoryCount;
 
+/**
+ * The namespace prefix of cache. It's used to prefix the namespace you provide to the caches's initializer. You 'd better name it with reverse domain name notation and keep the final dot.
+ * Defautls to `com.hackemist.SDImageCache.`, which will prefix your namespace such as `default` to final `com.hackemist.SDImageCache.default`. If you specify nil, it will be treated equals to an empty string.
+ */
+@property (copy, nonatomic, nullable) NSString *namespacePrefix;
+
 /**
  * The custom file manager for disk cache. Pass nil to let disk cache choose the proper file manager.
  * Defaults to nil.

SDWebImage/SDImageCacheConfig.m

@@ -32,6 +32,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
         _diskCacheWritingOptions = NSDataWritingAtomic;
         _maxCacheAge = kDefaultCacheMaxCacheAge;
         _maxCacheSize = 0;
+        _namespacePrefix = @"com.hackemist.SDImageCache.";
         _memoryCacheClass = [SDMemoryCache class];
         _diskCacheClass = [SDDiskCache class];
     }
@@ -49,6 +50,7 @@ static const NSInteger kDefaultCacheMaxCacheAge = 60 * 60 * 24 * 7; // 1 week
     config.maxCacheSize = self.maxCacheSize;
     config.maxMemoryCost = self.maxMemoryCost;
     config.maxMemoryCount = self.maxMemoryCount;
+    config.namespacePrefix = [self.namespacePrefix copyWithZone:zone];
     config.fileManager = self.fileManager; // NSFileManager does not conform to NSCopying, just pass the reference
     config.memoryCacheClass = self.memoryCacheClass;
     config.diskCacheClass = self.diskCacheClass;