Create `DaemonInstance` helper actor

1 files changed, 78 insertions, 0 deletions

diff --git a/android/src/main/kotlin/net/mullvad/mullvadvpn/service/DaemonInstance.kt b/android/src/main/kotlin/net/mullvad/mullvadvpn/service/DaemonInstance.kt
new file mode 100644
index 0000000000..291d9bb4cb
--- /dev/null
+++ b/android/src/main/kotlin/net/mullvad/mullvadvpn/service/DaemonInstance.kt
@@ -0,0 +1,78 @@
+package net.mullvad.mullvadvpn.service
+
+import kotlin.properties.Delegates.observable
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.channels.ClosedReceiveChannelException
+import kotlinx.coroutines.channels.ReceiveChannel
+import kotlinx.coroutines.channels.actor
+import kotlinx.coroutines.channels.sendBlocking
+
+class DaemonInstance(val vpnService: MullvadVpnService, val listener: (MullvadDaemon?) -> Unit) {
+    private enum class Command {
+        START,
+        STOP,
+    }
+
+    private val commandChannel = spawnActor()
+
+    private var daemon by observable<MullvadDaemon?>(null) { _, _, newInstance ->
+        listener(newInstance)
+    }
+
+    fun start() {
+        commandChannel.sendBlocking(Command.START)
+    }
+
+    fun stop() {
+        commandChannel.sendBlocking(Command.STOP)
+    }
+
+    fun onDestroy() {
+        commandChannel.close()
+    }
+
+    private fun spawnActor() = GlobalScope.actor<Command>(Dispatchers.Default, Channel.UNLIMITED) {
+        var isRunning = true
+
+        while (isRunning) {
+            if (!waitForCommand(channel, Command.START)) {
+                break
+            }
+
+            startDaemon()
+
+            isRunning = waitForCommand(channel, Command.STOP)
+
+            stopDaemon()
+        }
+    }
+
+    private suspend fun waitForCommand(
+        channel: ReceiveChannel<Command>,
+        command: Command
+    ): Boolean {
+        try {
+            while (channel.receive() != command) {
+                // Wait for command
+            }
+
+            return true
+        } catch (exception: ClosedReceiveChannelException) {
+            return false
+        }
+    }
+
+    private fun startDaemon() {
+        daemon = MullvadDaemon(vpnService).apply {
+            onDaemonStopped = {
+                daemon = null
+            }
+        }
+    }
+
+    private fun stopDaemon() {
+        daemon?.shutdown()
+    }
+}