Add support for service filtering during scanning (#117)

Author: burnhamd

core/api/core.api

@@ -220,7 +220,8 @@ public abstract interface class com/juul/kable/Scanner {
 }
 
 public final class com/juul/kable/ScannerKt {
-	public static final fun Scanner ()Lcom/juul/kable/Scanner;
+	public static final fun Scanner (Ljava/util/List;)Lcom/juul/kable/Scanner;
+	public static synthetic fun Scanner$default (Ljava/util/List;ILjava/lang/Object;)Lcom/juul/kable/Scanner;
 }
 
 public abstract interface class com/juul/kable/Service {

core/src/androidMain/kotlin/Scanner.kt

@@ -2,21 +2,25 @@ package com.juul.kable
 
 import android.bluetooth.BluetoothAdapter
 import android.bluetooth.le.ScanCallback
+import android.bluetooth.le.ScanFilter
 import android.bluetooth.le.ScanResult
+import android.bluetooth.le.ScanSettings
+import android.os.ParcelUuid
 import android.util.Log
+import com.benasher44.uuid.Uuid
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.channels.sendBlocking
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
 
 public class ScanFailedException internal constructor(
-    public val errorCode: Int
+    public val errorCode: Int,
 ) : IllegalStateException("Bluetooth scan failed with error code $errorCode")
 
-public actual fun Scanner(): Scanner = AndroidScanner()
+public actual fun Scanner(services: List<Uuid>?): Scanner = AndroidScanner(services)
 
-public class AndroidScanner internal constructor() : Scanner {
+public class AndroidScanner internal constructor(private val filterServices: List<Uuid>?) : Scanner {
 
     private val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
         ?: error("Bluetooth not supported")
@@ -47,7 +51,17 @@ public class AndroidScanner internal constructor() : Scanner {
                 cancel("Bluetooth scan failed", ScanFailedException(errorCode))
             }
         }
-        bluetoothAdapter.bluetoothLeScanner.startScan(callback)
+
+        val scanFilter =
+            filterServices
+                ?.map { ScanFilter.Builder().setServiceUuid(ParcelUuid(it)).build() }
+                ?.toList()
+        bluetoothAdapter.bluetoothLeScanner.startScan(
+            scanFilter,
+            ScanSettings.Builder().build(),
+            callback,
+        )
+
         awaitClose {
             bluetoothAdapter.bluetoothLeScanner.stopScan(callback)
         }

core/src/appleMain/kotlin/CentralManager.kt

@@ -29,7 +29,10 @@ public class CentralManager internal constructor() {
         options: Map<Any?, *>?,
     ) {
         withContext(dispatcher) {
-            cbCentralManager.scanForPeripheralsWithServices(services, options)
+            cbCentralManager.scanForPeripheralsWithServices(
+                serviceUUIDs = services?.map { it.toCBUUID() },
+                options = options,
+            )
         }
     }
 

core/src/appleMain/kotlin/Scanner.kt

@@ -13,7 +13,10 @@ import platform.CoreBluetooth.CBManagerStatePoweredOn
 import platform.CoreBluetooth.CBManagerStateUnauthorized
 import platform.CoreBluetooth.CBManagerStateUnsupported
 
-public actual fun Scanner(): Scanner = AppleScanner(CentralManager.Default, services = null)
+public actual fun Scanner(services: List<Uuid>?): Scanner = AppleScanner(
+    central = CentralManager.Default,
+    services = services,
+)
 
 public class AppleScanner internal constructor(
     central: CentralManager,

core/src/commonMain/kotlin/Scanner.kt

@@ -1,11 +1,10 @@
 package com.juul.kable
 
+import com.benasher44.uuid.Uuid
 import kotlinx.coroutines.flow.Flow
 
 public interface Scanner {
     public val advertisements: Flow<Advertisement>
 }
 
-// todo: Add support for specifying services to filter against (for platforms that support it).
-// https://github.com/JuulLabs/kable/issues/22
-public expect fun Scanner(): Scanner
+public expect fun Scanner(services: List<Uuid>? = null): Scanner

core/src/jsMain/kotlin/Scanner.kt

@@ -1,5 +1,6 @@
 package com.juul.kable
 
+import com.benasher44.uuid.Uuid
 import com.juul.kable.external.Bluetooth
 import com.juul.kable.external.BluetoothAdvertisingEvent
 import kotlinx.coroutines.await
@@ -11,7 +12,16 @@ import org.w3c.dom.events.Event
 
 private const val ADVERTISEMENT_RECEIVED_EVENT = "advertisementreceived"
 
-public actual fun Scanner(): Scanner = JsScanner(bluetooth, Options())
+public actual fun Scanner(services: List<Uuid>?): Scanner {
+    val filters = services
+        ?.map { it.toString() }
+        ?.toTypedArray()
+        ?.let { arrayOf<Options.Filter>(Options.Filter.Services(it)) }
+    return JsScanner(
+        bluetooth = bluetooth,
+        options = Options(filters = filters),
+    )
+}
 
 /**
  * Only available on Chrome 79+ with "Experimental Web Platform features" enabled via: