Bluetooth: macOS: DidModifyServices can happens while scanning

device/bluetooth/bluetooth_low_energy_device_mac.mm

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "device/bluetooth/bluetooth_low_energy_device_mac.h"
 
 #import <CoreFoundation/CoreFoundation.h>
 #include <stddef.h>
 
 #include "base/mac/mac_util.h"
@@ skipping 171 matching lines @@
   }
 }
 
 void BluetoothLowEnergyDeviceMac::DisconnectGatt() {
   GetMacAdapter()->DisconnectGatt(this);
 }
 
 void BluetoothLowEnergyDeviceMac::DidDiscoverPrimaryServices(NSError* error) {
   --discovery_pending_count_;
   if (discovery_pending_count_ < 0) {
-    // This should never happens, just in case it happens with a device,
+    // This should never happen, just in case it happens with a device,
     // discovery_pending_count_ is set back to 0.
     VLOG(1) << *this
             << ": BluetoothLowEnergyDeviceMac::discovery_pending_count_ "
             << discovery_pending_count_;
     discovery_pending_count_ = 0;
     return;
   }
   if (error) {
     // TODO(http://crbug.com/609320): Need to pass the error.
     // TODO(http://crbug.com/609844): Decide what to do if discover failed
@@ skipping 46 matching lines @@
     VLOG(1) << *this << ": Can't discover characteristics: "
             << BluetoothAdapterMac::String(error);
     return;
   }
 
   if (!IsGattConnected()) {
     VLOG(1) << *this << ": DidDiscoverCharacteristics, gatt disconnected.";
     // Don't create characteristics if the device disconnected.
     return;
   }
+  if (IsGattServicesDiscoveryComplete()) {
+    // This should never happen, just in case it happens with a device, this
+    // notification should be ignored.
+    VLOG(1) << *this
+            << ": Discovery complete, ignoring DidDiscoverCharacteristics.";
+    return;
+  }
 
   BluetoothRemoteGattServiceMac* gatt_service =
       GetBluetoothRemoteGattService(cb_service);
   DCHECK(gatt_service);
   gatt_service->DidDiscoverCharacteristics();
   SendNotificationIfDiscoveryComplete();
 }
 
 void BluetoothLowEnergyDeviceMac::DidModifyServices(
     NSArray* invalidatedServices) {
@@ skipping 51 matching lines @@
     // TODO(http://crbug.com/609844): Decide what to do if discover failed
     VLOG(1) << *this << ": Can't discover descriptors: "
             << BluetoothAdapterMac::String(error);
     return;
   }
   if (!IsGattConnected()) {
     VLOG(1) << *this << ": DidDiscoverDescriptors, disconnected.";
     // Don't discover descriptors if the device disconnected.
     return;
   }
+  if (IsGattServicesDiscoveryComplete()) {
+    // This should never happen, just in case it happens with a device, this
+    // notification should be ignored.
+    VLOG(1) << *this
+            << ": Discovery complete, ignoring DidDiscoverDescriptors.";
+    return;
+  }
   BluetoothRemoteGattServiceMac* gatt_service =
       GetBluetoothRemoteGattService(cb_characteristic.service);
   DCHECK(gatt_service);
   gatt_service->DidDiscoverDescriptors(cb_characteristic);
   SendNotificationIfDiscoveryComplete();
 }
 
 void BluetoothLowEnergyDeviceMac::DidUpdateValueForDescriptor(
     CBDescriptor* cb_descriptor,
     NSError* error) {
@@ skipping 33 matching lines @@
 }
 
 void BluetoothLowEnergyDeviceMac::DiscoverPrimaryServices() {
   VLOG(1) << *this << ": DiscoverPrimaryServices, pending count "
           << discovery_pending_count_;
   ++discovery_pending_count_;
   [GetPeripheral() discoverServices:nil];
 }
 
 void BluetoothLowEnergyDeviceMac::SendNotificationIfDiscoveryComplete() {
+  DCHECK(!IsGattServicesDiscoveryComplete());
   // Notify when all services have been discovered.
   bool discovery_complete =
       discovery_pending_count_ == 0 &&
       std::find_if_not(
           gatt_services_.begin(),
           gatt_services_.end(), [](GattServiceMap::value_type & pair) {
             BluetoothRemoteGattService* gatt_service = pair.second.get();
             return static_cast<BluetoothRemoteGattServiceMac*>(gatt_service)
                 ->IsDiscoveryComplete();
           }) == gatt_services_.end();
@@ skipping 73 matching lines @@
 std::ostream& operator<<(std::ostream& out,
                          const BluetoothLowEnergyDeviceMac& device) {
   // TODO(crbug.com/703878): Should use
   // BluetoothLowEnergyDeviceMac::GetNameForDisplay() instead.
   base::Optional<std::string> name = device.GetName();
   const char* name_cstr = name ? name->c_str() : "";
   return out << "<BluetoothLowEnergyDeviceMac " << device.GetAddress() << "/"
              << &device << ", \"" << name_cstr << "\">";
 }
 }  // namespace device