Implement GattClient#Disconnect for Apple implementation of BLEv2

PiperOrigin-RevId: 679218551

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTClient.h

@@ -49,6 +49,14 @@ typedef void (^GNCGetCharacteristicCompletionHandler)(
 typedef void (^GNCReadCharacteristicValueCompletionHandler)(NSData *_Nullable value,
                                                             NSError *_Nullable error);
 
+/**
+ * A block to be invoked after a call to @c disconnect, requesting that the local connection to the
+ * remote peripheral be cancelled.
+ *
+ * @param peripheral The remote peripheral to disconnect from.
+ */
+typedef void (^GNCRequestDisconnectionHandler)(id<GNCPeripheral> peripheral);
+
 /**
  * An object that can be used to discover, explore, and interact with GATT services and
  * characteristics available on a remote peripheral.
@@ -64,8 +72,11 @@ typedef void (^GNCReadCharacteristicValueCompletionHandler)(NSData *_Nullable va
  * Initializes the GATT client with a specified peripheral.
  *
  * @param peripheral The peripheral instance.
+ * @param requestDisconnectionHandler Called on a private queue with @c peripheral when the
+ *                                    connection to the peripheral should be cancelled.
  */
-- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral;
+- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler;
 
 /**
  * Discovers the specified characteristics of a service.
@@ -112,6 +123,9 @@ typedef void (^GNCReadCharacteristicValueCompletionHandler)(NSData *_Nullable va
                  completionHandler:
                      (nullable GNCReadCharacteristicValueCompletionHandler)completionHandler;
 
+/** Cancels an active or pending local connection to a peripheral. */
+- (void)disconnect;
+
 @end
 
 NS_ASSUME_NONNULL_END

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTClient.m

@@ -49,6 +49,7 @@ static NSError *AlreadyReadingCharacteristicError() {
 @implementation GNCBLEGATTClient {
   dispatch_queue_t _queue;
   id<GNCPeripheral> _peripheral;
+  GNCRequestDisconnectionHandler _requestDisconnectionHandler;
 
   /**
    * A map of service UUIDs with each service holding a map of a list of characterisitcs to a
@@ -70,15 +71,18 @@ static NSError *AlreadyReadingCharacteristicError() {
       *_readCharacteristicValueCompletionHandlers;
 }
 
-- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral {
-  return [self
-      initWithPeripheral:peripheral
-                   queue:dispatch_queue_create(kGNCBLEGATTClientQueueLabel, DISPATCH_QUEUE_SERIAL)];
+- (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler {
+  return [self initWithPeripheral:peripheral
+                            queue:dispatch_queue_create(kGNCBLEGATTClientQueueLabel,
+                                                        DISPATCH_QUEUE_SERIAL)
+      requestDisconnectionHandler:requestDisconnectionHandler];
 };
 
 // Private.
 - (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
-                             queue:(nullable dispatch_queue_t)queue {
+                             queue:(nullable dispatch_queue_t)queue
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler {
   self = [super init];
   if (self) {
     _queue = queue ?: dispatch_get_main_queue();
@@ -86,6 +90,7 @@ static NSError *AlreadyReadingCharacteristicError() {
     _peripheral.peripheralDelegate = self;
     _discoverCharacteristicsCompletionHandlers = [[NSMutableDictionary alloc] init];
     _readCharacteristicValueCompletionHandlers = [[NSMutableDictionary alloc] init];
+    _requestDisconnectionHandler = requestDisconnectionHandler;
   }
   return self;
 };
@@ -173,6 +178,12 @@ static NSError *AlreadyReadingCharacteristicError() {
   });
 }
 
+- (void)disconnect {
+  dispatch_async(_queue, ^{
+    _requestDisconnectionHandler(_peripheral);
+  });
+}
+
 #pragma mark - Internal
 
 - (CBCharacteristic *)synchronousCharacteristicWithUUID:(CBUUID *)characteristicUUID

internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEMedium.m

@@ -245,7 +245,13 @@ static NSError *AlreadyScanningError() {
   GNCGATTConnectionCompletionHandler handler = _connectionCompletionHandlers[peripheral.identifier];
   _connectionCompletionHandlers[peripheral.identifier] = nil;
   if (handler) {
-    GNCBLEGATTClient *client = [[GNCBLEGATTClient alloc] initWithPeripheral:peripheral];
+    GNCBLEGATTClient *client =
+        [[GNCBLEGATTClient alloc] initWithPeripheral:peripheral
+                         requestDisconnectionHandler:^(id<GNCPeripheral> peripheral) {
+                           dispatch_async(_queue, ^{
+                             [_centralManager cancelPeripheralConnection:peripheral];
+                           });
+                         }];
     handler(client, nil);
   }
 }

internal/platform/implementation/apple/Mediums/BLEv2/GNCCentralManager.h

@@ -79,6 +79,21 @@ NS_ASSUME_NONNULL_BEGIN
 - (void)connectPeripheral:(id<GNCPeripheral>)peripheral
                   options:(nullable NSDictionary<NSString *, id> *)options;
 
+/**
+ * Cancels an active or pending local connection to a peripheral.
+ *
+ * This method is nonblocking, and any @c CBPeripheral class commands that are still pending to
+ * @c peripheral may not complete. Because other apps may still have a connection to the peripheral,
+ * canceling a local connection doesn’t guarantee that the underlying physical link is immediately
+ * disconnected. From the app’s perspective, however, the peripheral is effectively disconnected,
+ * and the central manager object calls the @c centralManager:didDisconnectPeripheral:error: method
+ * of its delegate object.
+ *
+ * @param peripheral The peripheral to which the central manager is either trying to connect or has
+ * already connected.
+ */
+- (void)cancelPeripheralConnection:(id<GNCPeripheral>)peripheral;
+
 /** Asks the central manager to stop scanning for peripherals. */
 - (void)stopScan;
 

internal/platform/implementation/apple/Tests/GNCBLEGATTClient+Testing.h

@@ -31,9 +31,12 @@ NS_ASSUME_NONNULL_BEGIN
  * @param peripheral The peripheral instance.
  * @param queue The queue to run on, this must match the queue that the peripheral's delegate is
  *              running on. Defaults to the main queue when @c nil.
+ * @param requestDisconnectionHandler Called on a private queue with @c peripheral when the
+ *                                    connection to the peripheral should be cancelled.
  */
 - (instancetype)initWithPeripheral:(id<GNCPeripheral>)peripheral
-                             queue:(nullable dispatch_queue_t)queue;
+                             queue:(nullable dispatch_queue_t)queue
+       requestDisconnectionHandler:(GNCRequestDisconnectionHandler)requestDisconnectionHandler;
 
 @end
 

internal/platform/implementation/apple/Tests/GNCBLEGATTClientTest.m

@@ -19,6 +19,7 @@
 #import <XCTest/XCTest.h>
 
 #import "internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTCharacteristic.h"
+#import "internal/platform/implementation/apple/Mediums/BLEv2/GNCPeripheral.h"
 #import "internal/platform/implementation/apple/Tests/GNCBLEGATTClient+Testing.h"
 #import "internal/platform/implementation/apple/Tests/GNCFakePeripheral.h"
 
@@ -37,8 +38,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDiscoverCharacteristics {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -64,8 +68,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 
   fakePeripheral.discoverServicesError = [NSError errorWithDomain:@"fake" code:0 userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -97,8 +104,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                                                                               code:0
                                                                           userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -123,8 +133,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDuplicateDiscoverCharacteristics {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -163,8 +176,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDiscoverCharacteristicsMultipleCallsWithDifferentServices {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID1 = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *serviceUUID2 = [CBUUID UUIDWithString:kServiceUUID2];
@@ -209,8 +225,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDiscoverCharacteristicsMultipleCallsWithDifferentCharacteristics {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID1 = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -256,8 +275,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testGetCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -287,8 +309,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 
   fakePeripheral.discoverServicesError = [NSError errorWithDomain:@"fake" code:0 userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -324,8 +349,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                                                                               code:0
                                                                           userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -353,8 +381,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDuplicateGetCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -400,8 +431,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testGetNonExistentCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -425,8 +459,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testReadValueForCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -461,8 +498,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 
   fakePeripheral.discoverServicesError = [NSError errorWithDomain:@"fake" code:0 userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -503,8 +543,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                                                                               code:0
                                                                           userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -541,8 +584,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
                                                                        code:0
                                                                    userInfo:nil];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -576,8 +622,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testDuplicateReadValueForCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -630,8 +679,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testReadValueForMultipleCharacteristics {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID1 = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -691,8 +743,11 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
 - (void)testReadValueForUndiscoveredCharacteristic {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];
@@ -714,13 +769,33 @@ static NSString *const kCharacteristicUUID2 = @"00000000-0000-3000-8000-00000000
   [self waitForExpectations:@[ expectation ] timeout:3];
 }
 
+- (void)testDisconnect {
+  GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
+  XCTestExpectation *expectation = [[XCTestExpectation alloc] initWithDescription:@"Disconnect."];
+
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> peripheral) {
+                         XCTAssertNotNil(peripheral);
+                         [expectation fulfill];
+                       }];
+
+  [gattClient disconnect];
+
+  [self waitForExpectations:@[ expectation ] timeout:3];
+}
+
 #pragma mark - Delegate Calls
 
 - (void)testUnexpectedDelegateCalls {
   GNCFakePeripheral *fakePeripheral = [[GNCFakePeripheral alloc] init];
 
-  GNCBLEGATTClient *gattClient = [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
-                                                                        queue:nil];
+  GNCBLEGATTClient *gattClient =
+      [[GNCBLEGATTClient alloc] initWithPeripheral:fakePeripheral
+                                             queue:nil
+                       requestDisconnectionHandler:^(id<GNCPeripheral> __unused peripheral){
+                       }];
 
   CBUUID *serviceUUID = [CBUUID UUIDWithString:kServiceUUID1];
   CBUUID *characteristicUUID = [CBUUID UUIDWithString:kCharacteristicUUID1];

internal/platform/implementation/apple/Tests/GNCBLEMediumTest.m

@@ -18,6 +18,7 @@
 #import <Foundation/Foundation.h>
 #import <XCTest/XCTest.h>
 
+#import "internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTClient.h"
 #import "internal/platform/implementation/apple/Mediums/BLEv2/GNCBLEGATTServer.h"
 #import "internal/platform/implementation/apple/Mediums/BLEv2/GNCPeripheral.h"
 #import "internal/platform/implementation/apple/Tests/GNCBLEMedium+Testing.h"
@@ -313,8 +314,6 @@ static NSString *const kServiceUUID = @"0000FEF3-0000-1000-8000-00805F9B34FB";
 - (void)testDisconnect {
   GNCFakeCentralManager *fakeCentralManager = [[GNCFakeCentralManager alloc] init];
   GNCBLEMedium *medium = [[GNCBLEMedium alloc] initWithCentralManager:fakeCentralManager queue:nil];
-  XCTestExpectation *connectExpectation =
-      [[XCTestExpectation alloc] initWithDescription:@"Connect."];
   XCTestExpectation *disconnectExpectation =
       [[XCTestExpectation alloc] initWithDescription:@"Disconnect."];
 
@@ -327,13 +326,9 @@ static NSString *const kServiceUUID = @"0000FEF3-0000-1000-8000-00805F9B34FB";
       completionHandler:^(GNCBLEGATTClient *client, NSError *error) {
         XCTAssertNotNil(client);
         XCTAssertNil(error);
-        [connectExpectation fulfill];
+        [client disconnect];
       }];
 
-  [self waitForExpectations:@[ connectExpectation ] timeout:3];
-
-  [fakeCentralManager simulateCentralManagerDidDisconnectPeripheral:peripheral];
-
   [self waitForExpectations:@[ disconnectExpectation ] timeout:3];
 }
 

internal/platform/implementation/apple/Tests/GNCFakeCentralManager.m

@@ -56,6 +56,10 @@
   [centralDelegate gnc_centralManager:self didConnectPeripheral:peripheral];
 }
 
+- (void)cancelPeripheralConnection:(id<GNCPeripheral>)peripheral {
+  [centralDelegate gnc_centralManager:self didDisconnectPeripheral:peripheral error:nil];
+}
+
 - (void)stopScan {
 }
 

internal/platform/implementation/apple/ble_gatt_client.mm

@@ -127,8 +127,9 @@ bool GattClient::SetCharacteristicSubscription(
   return false;
 }
 
-// TODO(b/290385712): Implement.
-void GattClient::Disconnect() {}
+void GattClient::Disconnect() {
+  [gatt_client_ disconnect];
+}
 
 }  // namespace apple
 }  // namespace nearby

internal/platform/implementation/apple/ble_medium.mm

@@ -145,9 +145,15 @@ void BleMedium::HandleAdvertisementFound(id<GNCPeripheral> peripheral,
 std::unique_ptr<api::ble_v2::BleMedium::ScanningSession> BleMedium::StartScanning(
     const Uuid &service_uuid, api::ble_v2::TxPowerLevel tx_power_level,
     api::ble_v2::BleMedium::ScanningCallback callback) {
+  absl::MutexLock lock(&peripherals_mutex_);
   CBUUID *serviceUUID = CBUUID128FromCPP(service_uuid);
   scanning_cb_ = std::move(callback);
 
+  // Clear the map of discovered peripherals only when we are starting a new scan. If we cleared the
+  // map every time we stopped a scan, we would not be able to connect to peripherals that we
+  // discovered in that scan session.
+  peripherals_.clear();
+
   socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
   [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];
 
@@ -171,9 +177,15 @@ std::unique_ptr<api::ble_v2::BleMedium::ScanningSession> BleMedium::StartScannin
 
 bool BleMedium::StartScanning(const Uuid &service_uuid, api::ble_v2::TxPowerLevel tx_power_level,
                               api::ble_v2::BleMedium::ScanCallback callback) {
+  absl::MutexLock lock(&peripherals_mutex_);
   CBUUID *serviceUUID = CBUUID128FromCPP(service_uuid);
   scan_cb_ = std::move(callback);
 
+  // Clear the map of discovered peripherals only when we are starting a new scan. If we cleared the
+  // map every time we stopped a scan, we would not be able to connect to peripherals that we
+  // discovered in that scan session.
+  peripherals_.clear();
+
   socketCentralManager_ = [[GNSCentralManager alloc] initWithSocketServiceUUID:serviceUUID];
   [socketCentralManager_ startNoScanModeWithAdvertisedServiceUUIDs:@[ serviceUUID ]];