refactor: simplify NsdManager service handling

meshtastic · Jan 28, 2024 · 9194386 · 9194386
1 parent 8709c6b
commit 9194386
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Showing 2 changed files with 19 additions and 28 deletions.
diff --git a/app/src/main/java/com/geeksville/mesh/repository/network/NetworkRepository.kt b/app/src/main/java/com/geeksville/mesh/repository/network/NetworkRepository.kt
@@ -2,44 +2,21 @@ package com.geeksville.mesh.repository.network
 
 import android.net.ConnectivityManager
 import android.net.nsd.NsdManager
-import android.net.nsd.NsdServiceInfo
-import androidx.lifecycle.Lifecycle
-import androidx.lifecycle.coroutineScope
 import com.geeksville.mesh.android.Logging
-import com.geeksville.mesh.CoroutineDispatchers
-import kotlinx.coroutines.flow.MutableStateFlow
-import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.collectLatest
-import kotlinx.coroutines.flow.update
-import kotlinx.coroutines.launch
+import kotlinx.coroutines.flow.flowOf
 import javax.inject.Inject
 import javax.inject.Singleton
 
 @Singleton
 class NetworkRepository @Inject constructor(
-    dispatchers: CoroutineDispatchers,
-    processLifecycle: Lifecycle,
     private val nsdManagerLazy: dagger.Lazy<NsdManager?>,
     private val connectivityManager: dagger.Lazy<ConnectivityManager>,
 ) : Logging {
 
     val networkAvailable get() = connectivityManager.get().networkAvailable()
 
-    private val _resolvedList = MutableStateFlow<List<NsdServiceInfo>>(emptyList())
-    val resolvedList: StateFlow<List<NsdServiceInfo>> get() = _resolvedList
-
-    init {
-        processLifecycle.coroutineScope.launch(dispatchers.default) {
-            val manager = nsdManagerLazy.get() ?: return@launch
-            manager.discoverServices(SERVICE_TYPE).collectLatest { serviceList ->
-                _resolvedList.update {
-                    serviceList
-                        .filter { it.serviceName.contains(SERVICE_NAME) }
-                        .mapNotNull { manager.resolveService(it) }
-                }
-            }
-        }
-    }
+    val resolvedList
+        get() = nsdManagerLazy.get()?.serviceList(SERVICE_TYPE, SERVICE_NAME) ?: flowOf(emptyList())
 
     companion object {
         // To find all available services use SERVICE_TYPE = "_services._dns-sd._udp"

diff --git a/app/src/main/java/com/geeksville/mesh/repository/network/NsdManager.kt b/app/src/main/java/com/geeksville/mesh/repository/network/NsdManager.kt
@@ -2,14 +2,26 @@ package com.geeksville.mesh.repository.network
 
 import android.net.nsd.NsdManager
 import android.net.nsd.NsdServiceInfo
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.flow.mapLatest
 import kotlinx.coroutines.suspendCancellableCoroutine
 import kotlin.coroutines.resume
 
-internal fun NsdManager.discoverServices(
+@OptIn(ExperimentalCoroutinesApi::class)
+internal fun NsdManager.serviceList(
+    serviceType: String,
+    serviceName: String,
+): Flow<List<NsdServiceInfo>> = discoverServices(serviceType).mapLatest { serviceList ->
+    serviceList
+        .filter { it.serviceName.contains(serviceName) }
+        .mapNotNull { resolveService(it) }
+}
+
+private fun NsdManager.discoverServices(
     serviceType: String,
     protocolType: Int = NsdManager.PROTOCOL_DNS_SD,
 ): Flow<List<NsdServiceInfo>> = callbackFlow {
@@ -40,11 +52,13 @@ internal fun NsdManager.discoverServices(
             trySend(serviceList)
         }
     }
+    trySend(emptyList()) // Emit an initial empty list
     discoverServices(serviceType, protocolType, discoveryListener)
+
     awaitClose { stopServiceDiscovery(discoveryListener) }
 }
 
-internal suspend fun NsdManager.resolveService(
+private suspend fun NsdManager.resolveService(
     serviceInfo: NsdServiceInfo,
 ): NsdServiceInfo? = suspendCancellableCoroutine { continuation ->
     val listener = object : NsdManager.ResolveListener {