Auto merge of #22094 - asajeffrey:magicleap-shutdown, r=paulrouget

Shut down Servo when the ML app quits

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Shut down servo when shutting down the magic leap app.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes do not require tests because we don't test ML

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ports/libmlservo/src/lib.rs

@@ -47,6 +47,9 @@ use std::os::raw::c_char;
 use std::os::raw::c_void;
 use std::path::PathBuf;
 use std::rc::Rc;
+use std::thread;
+use std::time::Duration;
+use std::time::Instant;
 
 #[repr(u32)]
 pub enum MLLogLevel {
@@ -294,11 +297,30 @@ pub unsafe extern "C" fn navigate_servo(servo: *mut ServoInstance, text: *const
     }
 }
 
+// Some magic numbers for shutdown
+const SHUTDOWN_DURATION: Duration = Duration::from_secs(10);
+const SHUTDOWN_POLL_INTERVAL: Duration = Duration::from_millis(100);
+
 #[no_mangle]
 pub unsafe extern "C" fn discard_servo(servo: *mut ServoInstance) {
-    // Servo drop goes here!
-    if !servo.is_null() {
-        Box::from_raw(servo);
+    if let Some(servo) = servo.as_mut() {
+        let mut servo = Box::from_raw(servo);
+        let finish = Instant::now() + SHUTDOWN_DURATION;
+        servo.servo.handle_events(vec![WindowEvent::Quit]);
+        'outer: loop {
+            for (_, msg) in servo.servo.get_events() {
+                if let EmbedderMsg::Shutdown = msg {
+                    break 'outer;
+                }
+            }
+            if Instant::now() > finish {
+               warn!("Incomplete shutdown.");
+               break 'outer;
+            }
+            thread::sleep(SHUTDOWN_POLL_INTERVAL);
+            servo.servo.handle_events(vec![]);
+        }
+        servo.servo.deinit();
     }
 }
 

support/magicleap/Servo2D/code/src/Servo2D.cpp

@@ -59,8 +59,6 @@ Servo2D::Servo2D() {
 // Destroy a Servo 2D instance
 Servo2D::~Servo2D() {
   ML_LOG(Debug, "Servo2D Destructor.");
-  discard_servo(servo_);
-  servo_ = nullptr;
 }
 
 // The prism dimensions
@@ -168,6 +166,8 @@ int Servo2D::init() {
 
 int Servo2D::deInit() {
   ML_LOG(Debug, "Servo2D Deinitializing.");
+  discard_servo(servo_);
+  servo_ = nullptr;
   return 0;
 }