Merge pull request 'fix(android): hold WiFi+wake lock during UPnP cast (locked-screen poll starvation)' (#97) from dev into main

android/app/src/main/java/com/fabledsword/minstrel/player/CastNetworkLock.kt

@@ -0,0 +1,77 @@
+package com.fabledsword.minstrel.player
+
+import android.content.Context
+import android.net.wifi.WifiManager
+import android.os.Build
+import android.os.PowerManager
+import timber.log.Timber
+
+/**
+ * Holds a WiFi + CPU wake lock for the lifetime of an active UPnP cast.
+ *
+ * While casting, the wrapped ExoPlayer is paused, so its automatic
+ * `WAKE_MODE_NETWORK` locks are released and nothing keeps the phone's radio
+ * awake. On a locked, on-battery phone the WiFi enters power-save within
+ * seconds and the CPU dozes; that stalls the 1 Hz liveness poll to the
+ * renderer and the queue-extend calls to the server. The poll then trips the
+ * drop threshold and playback falls back to a phone that *also* has no
+ * network — silence, while the renderer was streaming fine the whole time.
+ *
+ * A high-performance / low-latency [WifiManager.WifiLock] keeps the radio out
+ * of power-save, and a partial [PowerManager.WakeLock] keeps the poll
+ * coroutine scheduled. Both are acquired when a route goes active and released
+ * the moment it drops or the user switches back to the phone.
+ *
+ * All methods are idempotent (`setReferenceCounted(false)` + held-checks) and
+ * synchronized, so they are safe to call from any thread.
+ */
+class CastNetworkLock(context: Context) {
+
+    private val appContext = context.applicationContext
+
+    private val wifiLock: WifiManager.WifiLock? =
+        (appContext.getSystemService(Context.WIFI_SERVICE) as? WifiManager)
+            ?.createWifiLock(wifiLockMode(), LOCK_TAG)
+            ?.apply { setReferenceCounted(false) }
+
+    private val wakeLock: PowerManager.WakeLock? =
+        (appContext.getSystemService(Context.POWER_SERVICE) as? PowerManager)
+            ?.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, LOCK_TAG)
+            ?.apply { setReferenceCounted(false) }
+
+    @Synchronized
+    fun acquire() {
+        runCatching { wifiLock?.takeUnless { it.isHeld }?.acquire() }
+            .onFailure { Timber.w(it, "CastNetworkLock: wifi acquire failed") }
+        runCatching { wakeLock?.takeUnless { it.isHeld }?.acquire() }
+            .onFailure { Timber.w(it, "CastNetworkLock: wake acquire failed") }
+        Timber.w(
+            "CastNetworkLock acquired (wifi=%s wake=%s)",
+            wifiLock?.isHeld, wakeLock?.isHeld,
+        )
+    }
+
+    @Synchronized
+    fun release() {
+        runCatching { wifiLock?.takeIf { it.isHeld }?.release() }
+            .onFailure { Timber.w(it, "CastNetworkLock: wifi release failed") }
+        runCatching { wakeLock?.takeIf { it.isHeld }?.release() }
+            .onFailure { Timber.w(it, "CastNetworkLock: wake release failed") }
+        Timber.w("CastNetworkLock released")
+    }
+
+    private companion object {
+        const val LOCK_TAG = "minstrel:upnp-cast"
+
+        // WIFI_MODE_FULL_LOW_LATENCY (API 29+) both disables power-save and
+        // lowers latency; FULL_HIGH_PERF is the pre-Q equivalent for keeping
+        // the radio fully awake.
+        fun wifiLockMode(): Int =
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
+                WifiManager.WIFI_MODE_FULL_LOW_LATENCY
+            } else {
+                @Suppress("DEPRECATION")
+                WifiManager.WIFI_MODE_FULL_HIGH_PERF
+            }
+    }
+}

android/app/src/main/java/com/fabledsword/minstrel/player/MinstrelForwardingPlayer.kt

@@ -63,6 +63,7 @@ class MinstrelForwardingPlayer(
     private val delegate: Player,
     private val holder: ActiveUpnpHolder,
     private val remoteState: RemotePlayerState,
+    private val castNetworkLock: CastNetworkLock,
     private val onDrop: (routeName: String) -> Unit,
 ) : ForwardingPlayer(delegate) {
 
@@ -438,6 +439,11 @@ class MinstrelForwardingPlayer(
         lastNotifiedTrackIdx = -1
         if (active != null) {
             Timber.w("UPnP active: %s -- pollLoop starting", active.routeName)
+            // Hold the WiFi + CPU awake for the cast: the wrapped ExoPlayer is
+            // about to be paused (releasing its WAKE_MODE_NETWORK locks), so
+            // without this the radio power-saves on a locked screen and the
+            // poll below starves -- see [CastNetworkLock].
+            castNetworkLock.acquire()
             // Pause the wrapped ExoPlayer so we are not playing local audio
             // simultaneously with the remote renderer. handler.post targets the
             // application looper, so this runs on the same thread that processes
@@ -447,6 +453,7 @@ class MinstrelForwardingPlayer(
             handler.post { delegate.pause() }
             pollJob = scope.launch { pollLoop(active) }
         } else {
+            castNetworkLock.release()
             remoteState.reset()
         }
     }

android/app/src/main/java/com/fabledsword/minstrel/player/PlayerFactory.kt

@@ -81,6 +81,7 @@ class PlayerFactory @Inject constructor(
             delegate = exo,
             holder = activeUpnpHolder,
             remoteState = remoteState,
+            castNetworkLock = CastNetworkLock(context),
             onDrop = { name -> emitDrop(name) },
         )
     }