fix(ios): Avoid "ghost" peripherals on iOS

Identified in don/cordova-plugin-ble-central#1039

Sometimes iOS will return a new CBPeripheral for an existing device.
When this happens, the original device stops working.

Now, the latest peripheral supplied by iOS is always attached to the
existing device wrapper

Author: peitschie

ios/Sources/BluetoothLe/Device.swift

@@ -37,6 +37,15 @@ class Device: NSObject, CBPeripheralDelegate {
         return self.peripheral
     }
 
+    func updatePeripheral(_ newPeripheral: CBPeripheral) {
+        guard newPeripheral.identifier == self.peripheral.identifier else {
+            log("Warning: Attempted to update peripheral with different UUID")
+            return
+        }
+        self.peripheral = newPeripheral
+        self.peripheral.delegate = self
+    }
+
     func setOnConnected(
         _ connectionTimeout: Double,
         _ callback: @escaping Callback

ios/Sources/BluetoothLe/DeviceManager.swift

@@ -181,9 +181,11 @@ class DeviceManager: NSObject, CBCentralManagerDelegate {
         guard ScanFilterUtils.passesServiceDataFilter(advertisementData, filters: self.serviceDataFilters) else { return }
 
         let deviceId = peripheral.identifier.uuidString
-        let result = self.discoveredDevices.getOrInsert(key: deviceId) {
-            Device(peripheral)
-        }
+        let result = self.discoveredDevices.getOrInsert(
+            key: deviceId,
+            create: { Device(peripheral) },
+            update: { $0.updatePeripheral(peripheral) }
+        )
         let device = result.value
         let isNew = result.wasInserted
 

ios/Sources/BluetoothLe/Plugin.swift

@@ -173,7 +173,11 @@ public class BluetoothLe: CAPPlugin, CAPBridgedPlugin {
                         call.reject("Device not found.")
                         return
                     }
-                    let storedDevice = self.deviceMap.getOrInsert(key: device.getId()) { device }.value
+                    let storedDevice = self.deviceMap.getOrInsert(
+                        key: device.getId(),
+                        create: { device },
+                        update: { $0.updatePeripheral(device.getPeripheral()) }
+                    ).value
                     let bleDevice: BleDevice = self.getBleDevice(storedDevice)
                     call.resolve(bleDevice)
                 } else {
@@ -210,7 +214,11 @@ public class BluetoothLe: CAPPlugin, CAPBridgedPlugin {
                     call.reject(message)
                 }
             }, { (device, advertisementData, rssi) in
-                let storedDevice = self.deviceMap.getOrInsert(key: device.getId()) { device }.value
+                let storedDevice = self.deviceMap.getOrInsert(
+                    key: device.getId(),
+                    create: { device },
+                    update: { $0.updatePeripheral(device.getPeripheral()) }
+                ).value
                 let data = self.getScanResult(storedDevice, advertisementData, rssi)
                 self.notifyListeners("onScanResult", data: data)
             }
@@ -235,9 +243,11 @@ public class BluetoothLe: CAPPlugin, CAPBridgedPlugin {
         let peripherals = deviceManager.getDevices(deviceUUIDs)
         let bleDevices: [BleDevice] = peripherals.map({peripheral in
             let deviceId = peripheral.identifier.uuidString
-            let device = self.deviceMap.getOrInsert(key: deviceId) {
-                Device(peripheral)
-            }.value
+            let device = self.deviceMap.getOrInsert(
+                key: deviceId,
+                create: { Device(peripheral) },
+                update: { $0.updatePeripheral(peripheral) }
+            ).value
             return self.getBleDevice(device)
         })
         call.resolve(["devices": bleDevices])
@@ -255,9 +265,11 @@ public class BluetoothLe: CAPPlugin, CAPBridgedPlugin {
         let peripherals = deviceManager.getConnectedDevices(serviceUUIDs)
         let bleDevices: [BleDevice] = peripherals.map({peripheral in
             let deviceId = peripheral.identifier.uuidString
-            let device = self.deviceMap.getOrInsert(key: deviceId) {
-                Device(peripheral)
-            }.value
+            let device = self.deviceMap.getOrInsert(
+                key: deviceId,
+                create: { Device(peripheral) },
+                update: { $0.updatePeripheral(peripheral) }
+            ).value
             return self.getBleDevice(device)
         })
         call.resolve(["devices": bleDevices])

ios/Sources/BluetoothLe/ThreadSafeDictionary.swift

@@ -42,4 +42,20 @@ class ThreadSafeDictionary<K: Hashable, T> {
             return (newValue, true)
         }
     }
+
+    /// Atomically gets existing value (calling update on it) or inserts new value
+    /// The create closure is only called if the key doesn't exist
+    /// The update closure is called on existing values before returning
+    /// Returns tuple of (value, wasInserted) where wasInserted indicates if a new value was created
+    func getOrInsert(key: K, create: () -> T, update: (T) -> Void) -> (value: T, wasInserted: Bool) {
+        return queue.sync(flags: .barrier) {
+            if let existing = dictionary[key] {
+                update(existing)
+                return (existing, false)
+            }
+            let newValue = create()
+            dictionary[key] = newValue
+            return (newValue, true)
+        }
+    }
 }