Merge pull request #2116 from dreampiggy/feature_invalidate_SDWebImageDownloader

Add a public API to allow user to invalidate URLSession used in SDWebImageDownloader to avoid memory leak on non-singleton instance

SDWebImage/SDWebImageDownloader.h

@@ -162,7 +162,7 @@ typedef SDHTTPHeadersDictionary * _Nullable (^SDWebImageDownloaderHeadersFilterB
 
 /**
  * Creates an instance of a downloader with specified session configuration.
- * *Note*: `timeoutIntervalForRequest` is going to be overwritten.
+ * @note `timeoutIntervalForRequest` is going to be overwritten.
  * @return new instance of downloader class
  */
 - (nonnull instancetype)initWithSessionConfiguration:(nullable NSURLSessionConfiguration *)sessionConfiguration NS_DESIGNATED_INITIALIZER;
@@ -239,11 +239,18 @@ typedef SDHTTPHeadersDictionary * _Nullable (^SDWebImageDownloaderHeadersFilterB
 /**
  * Forces SDWebImageDownloader to create and use a new NSURLSession that is
  * initialized with the given configuration.
- * *Note*: All existing download operations in the queue will be cancelled.
- * *Note*: `timeoutIntervalForRequest` is going to be overwritten.
+ * @note All existing download operations in the queue will be cancelled.
+ * @note `timeoutIntervalForRequest` is going to be overwritten.
  *
  * @param sessionConfiguration The configuration to use for the new NSURLSession
  */
 - (void)createNewSessionWithConfiguration:(nonnull NSURLSessionConfiguration *)sessionConfiguration;
 
+/**
+ * Invalidates the managed session, optionally canceling pending operations.
+ * @note If you use custom downloader instead of the shared downloader, you need call this method when you do not use it to avoid memory leak
+ * @param cancelPendingOperations Whether or not to cancel pending operations.
+ */
+- (void)invalidateSessionAndCancel:(BOOL)cancelPendingOperations;
+
 @end

SDWebImage/SDWebImageDownloader.m

@@ -107,6 +107,14 @@
                                             delegateQueue:nil];
 }
 
+- (void)invalidateSessionAndCancel:(BOOL)cancelPendingOperations {
+    if (cancelPendingOperations) {
+        [self.session invalidateAndCancel];
+    } else {
+        [self.session finishTasksAndInvalidate];
+    }
+}
+
 - (void)dealloc {
     [self.session invalidateAndCancel];
     self.session = nil;

Tests/Tests/SDWebImageDownloaderTests.m

@@ -61,6 +61,7 @@
 - (void)test01ThatSharedDownloaderIsNotEqualToInitDownloader {
     SDWebImageDownloader *downloader = [[SDWebImageDownloader alloc] init];
     expect(downloader).toNot.equal([SDWebImageDownloader sharedDownloader]);
+    [downloader invalidateSessionAndCancel:YES];
 }
 
 - (void)test02ThatByDefaultDownloaderSetsTheAcceptHTTPHeader {
@@ -377,6 +378,7 @@
     }];
     
     [self waitForExpectationsWithCommonTimeout];
+    [downloader invalidateSessionAndCancel:YES];
 }
 
 @end