[client] transport: track video component availability

client/src/sw_surface.c

@@ -0,0 +1,84 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include "sw_surface.h"
+
+#include "common/debug.h"
+#include "common/thread.h"
+#include "common/time.h"
+
+#include <stdatomic.h>
+
+struct SwSurfaceCall
+{
+  const LG_SwSurfaceOps * ops;
+  LG_Transport          * transport;
+  bool                    active;
+  bool                    result;
+  atomic_bool             done;
+};
+
+static int swSurfaceCallThread(void * opaque)
+{
+  struct SwSurfaceCall * call = opaque;
+  call->result = call->ops->setActive(call->transport, call->active);
+  atomic_store_explicit(&call->done, true, memory_order_release);
+  return 0;
+}
+
+bool lgSwSurface_setActive(const LG_SwSurfaceOps * ops,
+    LG_Transport * transport, bool active,
+    LG_TransportCancelledFn cancelled, void * opaque)
+{
+  if (!ops || !ops->setActive || !ops->cancelPending || !transport)
+    return false;
+
+  struct SwSurfaceCall call =
+  {
+    .ops       = ops,
+    .transport = transport,
+    .active    = active,
+  };
+  atomic_init(&call.done, false);
+
+  LGThread * thread;
+  if (!lgCreateThread("surfaceState", swSurfaceCallThread, &call, &thread))
+    return false;
+
+  bool cancelRequested = false;
+  while (!atomic_load_explicit(&call.done, memory_order_acquire))
+  {
+    if (active && cancelled && cancelled(opaque))
+    {
+      cancelRequested = true;
+      ops->cancelPending(transport);
+    }
+    nsleep(1000000U);
+  }
+
+  if (active && cancelled && cancelled(opaque))
+    cancelRequested = true;
+
+  if (!lgJoinThread(thread, NULL))
+  {
+    DEBUG_ERROR("Failed to join software surface state worker");
+    return false;
+  }
+  if (active && cancelRequested)
+  {
+    /* The backend may complete successfully at the same instant cancellation
+     * is observed. Leave it inactive before reporting the cancelled result. */
+    if (!ops->setActive(transport, false))
+      DEBUG_ERROR("Failed to deactivate a cancelled software surface");
+    return false;
+  }
+  return call.result;
+}