Auto merge of #23300 - jdm:helpful-ml, r=asajeffrey

Magic Leap developer ergonomic improvements

These changes allow passing in command line arguments for Servo via a SERVO_ARGS from the mldb terminal when launching the activity, as well as passing in a launch URL as an argument. It also redirects stdout to the ML log, which allows observing the built-in profiler output.

---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #23041
- [x] These changes do not require tests because no magic leap testing.

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support/magicleap/Servo2D/code/inc/Servo2D.h

@@ -29,7 +29,7 @@ public:
   /**
    * Constructs the Landscape Application.
    */
-  Servo2D();
+  Servo2D(const char* uri, const char* args);
 
   /**
    * Destroys the Landscape Application.
@@ -144,4 +144,6 @@ private:
   glm::quat controller_orientation_; // The last recorded orientation of the controller (in world coords)
   bool controller_trigger_down_ = false; // Is the controller trigger currently down?
   ServoInstance* servo_ = nullptr; // the servo instance we're embedding
+  const char* uri_ = nullptr;
+  const char* args_ = nullptr;
 };

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

@@ -68,7 +68,7 @@ void keyboard(Servo2D* app, bool visible) {
 // The functions Servo provides for hooking up to the ML.
 extern "C" ServoInstance* init_servo(EGLContext, EGLSurface, EGLDisplay,
                                      Servo2D*, MLLogger, MLHistoryUpdate, MLURLUpdate, MLKeyboard,
-                                     const char* url, int width, int height, float hidpi);
+                                     const char* url, const char* args, int width, int height, float hidpi);
 extern "C" void heartbeat_servo(ServoInstance*);
 extern "C" void keyboard_servo(ServoInstance*, char32_t code, lumin::ui::KeyType keyType);
 extern "C" void trigger_servo(ServoInstance*, float x, float y, bool down);
@@ -78,7 +78,10 @@ extern "C" void navigate_servo(ServoInstance*, const char* text);
 extern "C" void discard_servo(ServoInstance*);
 
 // Create a Servo2D instance
-Servo2D::Servo2D() {
+Servo2D::Servo2D(const char* uri, const char* args)
+: uri_(uri ? uri : HOME_PAGE)
+, args_(args)
+{
   ML_LOG(Debug, "Servo2D Constructor.");
 }
 
@@ -171,7 +174,7 @@ int Servo2D::init() {
   EGLDisplay dpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);
 
   // Hook into servo
-  servo_ = init_servo(ctx, surf, dpy, this, logger, history, url, keyboard, HOME_PAGE, VIEWPORT_W, VIEWPORT_H, HIDPI);
+  servo_ = init_servo(ctx, surf, dpy, this, logger, history, url, keyboard, uri_, args_, VIEWPORT_W, VIEWPORT_H, HIDPI);
   if (!servo_) {
     ML_LOG(Error, "Servo2D Failed to init servo instance");
     abort();

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

@@ -3,11 +3,34 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 #include <Servo2D.h>
+#include <ml_lifecycle.h>
 #include <ml_logging.h>
 
 int main(int argc, char **argv)
 {
   ML_LOG(Debug, "Servo2D Starting.");
-  Servo2D myApp;
-  return myApp.run();
+
+  // Handle optional initialization string passed via 'mldb launch'
+  MLLifecycleInitArgList* list = NULL;
+  MLLifecycleGetInitArgList(&list);
+  const char* uri = NULL;
+  if (nullptr != list) {
+    int64_t list_length = 0;
+    MLLifecycleGetInitArgListLength(list, &list_length);
+    if (list_length > 0) {
+      const MLLifecycleInitArg* iarg = NULL;
+      MLLifecycleGetInitArgByIndex(list, 0, &iarg);
+      if (nullptr != iarg) {
+        MLLifecycleGetInitArgUri(iarg, &uri);
+      }
+    }
+  }
+
+  const char* args = getenv("SERVO_ARGS");
+
+  Servo2D myApp(uri, args);
+  int rv = myApp.run();
+
+  MLLifecycleFreeInitArgList(&list);
+  return rv;
 }