setup test to use custom queue for RCTBlobManager operations instead of module queue

packages/react-native/Libraries/Blob/RCTBlobCollector.mm

@@ -21,7 +21,7 @@
 {
   RCTBlobManager *blobManager = blobManager_;
   NSString *blobId = [NSString stringWithUTF8String:blobId_.c_str()];
-  dispatch_async([blobManager_ methodQueue], ^{
+  dispatch_async([blobManager_ executionQueue], ^{
     [blobManager remove:blobId];
   });
 }

packages/react-native/Libraries/Blob/RCTBlobManager.h

@@ -10,6 +10,8 @@
 #import <React/RCTInitializing.h>
 #import <React/RCTURLRequestHandler.h>
 
+RCT_EXTERN void RCTEnableBlobManagerProcessingQueue(BOOL enabled);
+
 @interface RCTBlobManager : NSObject <RCTBridgeModule, RCTURLRequestHandler, RCTInitializing>
 
 - (NSString *)store:(NSData *)data;
@@ -26,4 +28,6 @@
 
 - (void)createFromParts:(NSArray<NSDictionary<NSString *, id> *> *)parts withId:(NSString *)blobId;
 
+- (dispatch_queue_t)executionQueue;
+
 @end

packages/react-native/Libraries/Blob/RCTBlobManager.mm

@@ -11,13 +11,24 @@
 
 #import <FBReactNativeSpec/FBReactNativeSpec.h>
 #import <React/RCTConvert.h>
+#import <React/RCTMockDef.h>
 #import <React/RCTNetworking.h>
 #import <React/RCTUtils.h>
 #import <React/RCTWebSocketModule.h>
 
 #import "RCTBlobCollector.h"
 #import "RCTBlobPlugins.h"
 
+RCT_MOCK_DEF(RCTBlobManager, dispatch_async);
+#define dispatch_async RCT_MOCK_USE(RCTBlobManager, dispatch_async)
+
+static BOOL gBlobManagerProcessingQueueEnabled = NO;
+
+RCT_EXTERN void RCTEnableBlobManagerProcessingQueue(BOOL enabled)
+{
+  gBlobManagerProcessingQueueEnabled = enabled;
+}
+
 static NSString *const kBlobURIScheme = @"blob";
 
 @interface RCTBlobManager () <
@@ -35,6 +46,7 @@ @implementation RCTBlobManager {
   std::mutex _blobsMutex;
 
   NSOperationQueue *_queue;
+  dispatch_queue_t _processingQueue;
 }
 
 RCT_EXPORT_MODULE(BlobModule)
@@ -48,6 +60,10 @@ - (void)initialize
   std::lock_guard<std::mutex> lock(_blobsMutex);
   _blobs = [NSMutableDictionary new];
 
+  if (gBlobManagerProcessingQueueEnabled) {
+    _processingQueue = dispatch_queue_create("com.facebook.react.blobmanager.processing", DISPATCH_QUEUE_SERIAL);
+  }
+
   facebook::react::RCTBlobCollector::install(self);
 }
 
@@ -194,12 +210,22 @@ - (void)remove:(NSString *)blobId
       [NSException raise:@"Invalid type for blob" format:@"%@ is invalid", type];
     }
   }
-  [self store:data withId:blobId];
+
+  dispatch_async([self executionQueue], ^{
+    [self store:data withId:blobId];
+  });
 }
 
 RCT_EXPORT_METHOD(release : (NSString *)blobId)
 {
-  [self remove:blobId];
+  dispatch_async([self executionQueue], ^{
+    [self remove:blobId];
+  });
+}
+
+- (dispatch_queue_t)executionQueue
+{
+  return gBlobManagerProcessingQueueEnabled ? _processingQueue : _methodQueue;
 }
 
 #pragma mark - RCTURLRequestHandler methods

packages/react-native/Libraries/Blob/RCTFileReaderModule.mm

@@ -31,7 +31,7 @@ @implementation RCTFileReaderModule
                   : (RCTPromiseRejectBlock)reject)
 {
   RCTBlobManager *blobManager = [_moduleRegistry moduleForName:"BlobModule"];
-  dispatch_async(blobManager.methodQueue, ^{
+  dispatch_async([blobManager executionQueue], ^{
     NSData *data = [blobManager resolve:blob];
 
     if (data == nil) {
@@ -62,7 +62,7 @@ @implementation RCTFileReaderModule
                   : (RCTPromiseRejectBlock)reject)
 {
   RCTBlobManager *blobManager = [_moduleRegistry moduleForName:"BlobModule"];
-  dispatch_async(blobManager.methodQueue, ^{
+  dispatch_async([blobManager executionQueue], ^{
     NSData *data = [blobManager resolve:blob];
 
     if (data == nil) {

packages/rn-tester/RNTesterUnitTests/RCTBlobManagerTests.m

@@ -8,6 +8,15 @@
 #import <XCTest/XCTest.h>
 
 #import <React/RCTBlobManager.h>
+#import <React/RCTMockDef.h>
+
+RCT_MOCK_REF(RCTBlobManager, dispatch_async);
+
+static void _mock_dispatch_async(dispatch_queue_t queue, dispatch_block_t block)
+{
+  XCTAssertNotNil(queue);
+  block();
+}
 
 @interface RCTBlobManagerTests : XCTestCase
 
@@ -23,8 +32,12 @@ - (void)setUp
 {
   [super setUp];
 
+  RCT_MOCK_SET(RCTBlobManager, dispatch_async, _mock_dispatch_async);
+
   _module = [RCTBlobManager new];
+  dispatch_queue_t methodQueue = dispatch_queue_create("test.queue", DISPATCH_QUEUE_SERIAL);
   [_module setValue:nil forKey:@"bridge"];
+  [_module setValue:methodQueue forKey:@"methodQueue"];
   [_module initialize];
   NSInteger size = 120;
   _data = [NSMutableData dataWithCapacity:size];
@@ -36,6 +49,13 @@ - (void)setUp
   [_module store:_data withId:_blobId];
 }
 
+- (void)tearDown
+{
+  [super tearDown];
+
+  RCT_MOCK_RESET(RCTBlobManager, dispatch_async);
+}
+
 - (void)testResolve
 {
   XCTAssertTrue([_data isEqualToData:[_module resolve:_blobId offset:0 size:_data.length]]);
@@ -98,4 +118,37 @@ - (void)testCreateFromParts
   XCTAssertTrue([expectedData isEqualToData:result]);
 }
 
+- (void)testCreateFromPartsProcessingQueue
+{
+  RCTEnableBlobManagerProcessingQueue(YES);
+  [self setUp];
+
+  NSDictionary<NSString *, id> *blobData = @{
+    @"blobId" : _blobId,
+    @"offset" : @0,
+    @"size" : @(_data.length),
+  };
+  NSDictionary<NSString *, id> *blob = @{
+    @"data" : blobData,
+    @"type" : @"blob",
+  };
+  NSString *stringData = @"i \u2665 dogs";
+  NSDictionary<NSString *, id> *string = @{
+    @"data" : stringData,
+    @"type" : @"string",
+  };
+  NSString *resultId = [NSUUID UUID].UUIDString;
+  NSArray<id> *parts = @[ blob, string ];
+
+  [_module createFromParts:parts withId:resultId];
+
+  NSMutableData *expectedData = [NSMutableData new];
+  [expectedData appendData:_data];
+  [expectedData appendData:[stringData dataUsingEncoding:NSUTF8StringEncoding]];
+
+  NSData *result = [_module resolve:resultId offset:0 size:expectedData.length];
+
+  XCTAssertTrue([expectedData isEqualToData:result]);
+}
+
 @end