app: harden mirroring lifecycle and state

1 files changed, 38 insertions, 7 deletions

diff --git a/app/src/main/java/invalid/lena/scrcpy/AudioStream.java b/app/src/main/java/invalid/lena/scrcpy/AudioStream.java
index 7fe33f0..13b39f5 100644
--- a/app/src/main/java/invalid/lena/scrcpy/AudioStream.java
+++ b/app/src/main/java/invalid/lena/scrcpy/AudioStream.java
@@ -2,6 +2,7 @@ package invalid.lena.scrcpy;
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.concurrent.TimeUnit;
 
 // Reads the scrcpy audio socket and drives an AudioFrames sink.
 //
@@ -23,16 +24,34 @@ public final class AudioStream {
     // Generous upper bound for one audio packet (a raw PCM block or an
     // opus packet is a few KB). A corrupt or hostile length field must
     // not drive the allocation below.
-    private static final int MAX_FRAME_SIZE = 1024 * 1024;
+    private static final int MAX_FRAME_SIZE = 256 * 1024;
 
     private final InputStream  source;
     private final AudioFrames  sink;
+    private final Runnable     onFatalError;
     private Thread             thread;
     private volatile boolean   stop;
 
+    // Liveness signal for Session's stall watchdog. The audio socket is
+    // the only one that is reliably continuous: the server captures PCM
+    // at 48 kHz whether or not anything on the target's screen moves, so
+    // silence here means the wire is gone. Video is useless for this - a
+    // static screen queues nothing to the encoder and legitimately
+    // produces no frames for minutes.
+    private volatile boolean started;
+    private volatile long    lastPacketAtMs;
+
+    public boolean isStarted()      { return started; }
+    public long    lastPacketAtMs() { return lastPacketAtMs; }
+
     public AudioStream(InputStream source, AudioFrames sink) {
+        this(source, sink, null);
+    }
+
+    public AudioStream(InputStream source, AudioFrames sink, Runnable onFatalError) {
         this.source = source;
         this.sink = sink;
+        this.onFatalError = onFatalError;
     }
 
     public void start() {
@@ -60,16 +79,15 @@ public final class AudioStream {
                 return;
             }
             if (fourcc == 1) {
-                Log.e("audio: server reports configuration error");
-                return;
+                throw new IOException("audio: server reports configuration error");
             }
             if (fourcc != Wire.CODEC_RAW && fourcc != Wire.CODEC_OPUS) {
-                Log.w("audio: unexpected codec %s - keeping silent",
-                        Wire.fourccName(fourcc));
-                return;
+                throw new IOException("audio: unexpected codec " + Wire.fourccName(fourcc));
             }
             Log.i("audio meta codec=%s", Wire.fourccName(fourcc));
             sink.start(fourcc);
+            lastPacketAtMs = monotonicMs();
+            started = true;
 
             byte[] hdr = new byte[12];
             byte[] payload = new byte[16 * 1024];
@@ -84,15 +102,28 @@ public final class AudioStream {
                 }
                 if (size > payload.length) payload = new byte[size];
                 Wire.readFully(source, payload, 0, size);
+                lastPacketAtMs = monotonicMs();
                 sink.feed(payload, 0, size, cfg);
                 if (++frames == 1) Log.i("audio frame n=1 size=%d cfg=%s", size, cfg);
             }
         } catch (IOException e) {
-            if (!stop) Log.e(e, "audio reader");
+            if (!stop) {
+                Log.e(e, "audio reader");
+                reportFatal();
+            }
         } catch (Exception e) {
             Log.e(e, "audio reader unexpected");
+            if (!stop) reportFatal();
         } finally {
             Log.i("audio reader: end");
         }
     }
+
+    private void reportFatal() {
+        if (onFatalError != null) onFatalError.run();
+    }
+
+    private static long monotonicMs() {
+        return TimeUnit.NANOSECONDS.toMillis(System.nanoTime());
+    }
 }