fix: make loop_count atomic and increase remove channel delay

Co-authored-by: aider (deepseek/deepseek-reasoner) <aider@aider.chat>

src/channel.h

@@ -21,7 +21,7 @@ struct channel_t {
     atomic_int    state;
     int           prev_state;
     float         loop_buffer[LOOP_BUF_SIZE];
-    int           loop_count;
+    atomic_int    loop_count;
     int           record_pos;
     int           playback_pos;
     atomic_int    active;

src/looper.c

@@ -72,11 +72,11 @@ int process_callback(jack_nframes_t nframes, void *arg) {
       switch (state) {
       case STATE_RECORD:
         channels[c].record_pos = 0;
-        channels[c].loop_count = 0;
+        atomic_store(&channels[c].loop_count, 0);
         break;
       case STATE_LOOPING:
         if (channels[c].prev_state == STATE_RECORD && channels[c].record_pos > 0)
-          channels[c].loop_count = channels[c].record_pos;
+          atomic_store(&channels[c].loop_count, channels[c].record_pos);
         channels[c].playback_pos = 0;
         break;
       default:
@@ -102,12 +102,13 @@ int process_callback(jack_nframes_t nframes, void *arg) {
       break;
 
     case STATE_LOOPING:
-      if (channels[c].loop_count > 0) {
+      int lc = atomic_load(&channels[c].loop_count);
+      if (lc > 0) {
         float *outf = (float *)out;
         for (i = 0; i < nframes; i++) {
           outf[i] = channels[c].loop_buffer[channels[c].playback_pos];
           channels[c].playback_pos =
-              (channels[c].playback_pos + 1) % channels[c].loop_count;
+              (channels[c].playback_pos + 1) % lc;
         }
       } else {
         memset(out, 0, sizeof(jack_default_audio_sample_t) * nframes);
@@ -130,7 +131,7 @@ int process_callback(jack_nframes_t nframes, void *arg) {
     // push loop output into save ring if saving (atomic load)
     RingBuf *r = (RingBuf *)atomic_load_explicit(&channels[c].save_ring, memory_order_acquire);
     if (r != NULL) {
-      if (state == STATE_LOOPING && channels[c].loop_count > 0) {
+      if (state == STATE_LOOPING && atomic_load(&channels[c].loop_count) > 0) {
           float *outf = (float *)out;
           ring_write(r, outf, nframes);
       }
@@ -236,7 +237,8 @@ static void *writer_thread(void *arg) {
     unsigned sr = (unsigned)global_sample_rate;
     if (sr == 0) sr = 48000;
 
-    float *outbuf = malloc((size_t)ch->loop_count * sizeof(float));
+    int lc = atomic_load(&ch->loop_count);
+    float *outbuf = malloc((size_t)lc * sizeof(float));
     if (!outbuf) {
         ring_destroy(ring);
         free(ring);
@@ -244,7 +246,7 @@ static void *writer_thread(void *arg) {
         return NULL;
     }
     size_t collected = 0;
-    size_t want = (size_t)ch->loop_count;
+    size_t want = (size_t)lc;
     while (collected < want) {
         size_t got = ring_read(ring, outbuf + collected, want - collected);
         collected += got;
@@ -253,7 +255,7 @@ static void *writer_thread(void *arg) {
             nanosleep(&req, NULL);
         }
     }
-    wav_write(path, outbuf, ch->loop_count, sr);
+    wav_write(path, outbuf, (unsigned)lc, sr);
     free(outbuf);
 
     ring_destroy(ring);
@@ -307,7 +309,7 @@ void looper_process_commands(jack_client_t *client) {
     if (wav_read("loop.wav", &buf, &frames) == 0 && frames > 0) {
       if (frames > LOOP_BUF_SIZE) frames = LOOP_BUF_SIZE;
       memcpy(channels[0].loop_buffer, buf, frames * sizeof(float));
-      channels[0].loop_count  = (int)frames;
+      atomic_store(&channels[0].loop_count, (int)frames);
       channels[0].record_pos  = 0;
       channels[0].playback_pos = 0;
       atomic_store(&channels[0].state, STATE_LOOPING);
@@ -320,12 +322,13 @@ void looper_process_commands(jack_client_t *client) {
 
   /* ---------- save command (writer thread) ---------- */
   if (atomic_exchange(&cmd_save, 0)) {
+    int lc = atomic_load(&channels[0].loop_count);
     if (atomic_load(&channels[0].state) == STATE_LOOPING &&
-        channels[0].loop_count > 0 &&
+        lc > 0 &&
         channels[0].save_ring == NULL) {
       RingBuf *ring = (RingBuf*)malloc(sizeof(RingBuf));
       if (ring) {
-        size_t sz = (size_t)channels[0].loop_count * 2;
+        size_t sz = (size_t)lc * 2;
         if (ring_init(ring, sz) == 0) {
           atomic_store_explicit(&channels[0].save_ring, (_Atomic RingBuf *)ring, memory_order_release);
           pthread_t th;

tests/integration.c

@@ -819,7 +819,7 @@ static int test_remove_channel(void) {
         fprintf(stderr, "  FAIL: send note 61 failed\n");
         return 1;
     }
-    safe_usleep(1500000);
+    safe_usleep(3000000);
     /* verify channel1_input has disappeared */
     ports = jack_get_ports(client, NULL, JACK_DEFAULT_AUDIO_TYPE, 0);
     int still_found = 0;