Merge pull request #8452 from JosJuice/android-emulationactivity-rotation-crash

Android: Replace emulation rotation crash workaround with proper fix

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/NativeLibrary.java

@@ -400,6 +400,8 @@ public final class NativeLibrary
    */
   public static native void StopEmulation();
 
+  public static native void WaitUntilDoneBooting();
+
   /**
    * Returns true if emulation is running (or is paused).
    */

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/activities/EmulationActivity.java

@@ -235,10 +235,6 @@ public final class EmulationActivity extends AppCompatActivity
   {
     super.onCreate(savedInstanceState);
 
-    // Find the EmulationFragment
-    mEmulationFragment = (EmulationFragment) getSupportFragmentManager()
-            .findFragmentById(R.id.frame_emulation_fragment);
-
     if (savedInstanceState == null)
     {
       // Get params we were passed
@@ -251,9 +247,7 @@ public final class EmulationActivity extends AppCompatActivity
     }
     else
     {
-      // Could have recreated the activity(rotate) before creating the fragment. If the fragment
+      activityRecreated = true;
-      // doesn't exist, treat this as a new start.
-      activityRecreated = mEmulationFragment != null;
       restoreState(savedInstanceState);
     }
 
@@ -311,9 +305,10 @@ public final class EmulationActivity extends AppCompatActivity
       setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE);
     }
 
-    if (!(mDeviceHasTouchScreen && lockLandscape &&
+    // Find or create the EmulationFragment
-            getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) &&
+    mEmulationFragment = (EmulationFragment) getSupportFragmentManager()
-            mEmulationFragment == null)
+            .findFragmentById(R.id.frame_emulation_fragment);
+    if (mEmulationFragment == null)
     {
       mEmulationFragment = EmulationFragment.newInstance(mPaths);
       getSupportFragmentManager().beginTransaction()

Source/Android/app/src/main/java/org/dolphinemu/dolphinemu/fragments/EmulationFragment.java

@@ -316,8 +316,6 @@ public final class EmulationFragment extends Fragment implements SurfaceHolder.C
         state = State.PAUSED;
         Log.debug("[EmulationFragment] Pausing emulation.");
 
-        // Release the surface before pausing, since emulation has to be running for that.
-        NativeLibrary.SurfaceDestroyed();
         NativeLibrary.PauseEmulation();
       }
       else
@@ -381,19 +379,17 @@ public final class EmulationFragment extends Fragment implements SurfaceHolder.C
         mSurface = null;
         Log.debug("[EmulationFragment] Surface destroyed.");
 
-        if (state == State.RUNNING)
+        if (state != State.STOPPED)
         {
-          NativeLibrary.SurfaceDestroyed();
+          // In order to avoid dereferencing nullptr, we must not destroy the surface while booting
-          state = State.PAUSED;
+          // the core, so wait here if necessary. An easy (but not 100% consistent) way to reach
-        }
+          // this method while the core is booting is by having landscape orientation lock enabled
-        else if (state == State.PAUSED)
+          // and starting emulation while the phone is in portrait mode, leading to the activity
-        {
+          // being recreated very soon after NativeLibrary.Run has been called.
-          Log.warning("[EmulationFragment] Surface cleared while emulation paused.");
+          NativeLibrary.WaitUntilDoneBooting();
-        }
-        else
-        {
-          Log.warning("[EmulationFragment] Surface cleared while emulation stopped.");
         }
+
+        NativeLibrary.SurfaceDestroyed();
       }
     }
 

Source/Android/jni/MainAndroid.cpp

@@ -197,6 +197,8 @@ JNIEXPORT void JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_PauseEmulati
                                                                                    jobject obj);
 JNIEXPORT void JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_StopEmulation(JNIEnv* env,
                                                                                   jobject obj);
+JNIEXPORT void JNICALL
+Java_org_dolphinemu_dolphinemu_NativeLibrary_WaitUntilDoneBooting(JNIEnv* env, jobject obj);
 JNIEXPORT jboolean JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_IsRunning(JNIEnv* env,
                                                                                   jobject obj);
 JNIEXPORT jboolean JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_onGamePadEvent(
@@ -283,6 +285,12 @@ JNIEXPORT void JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_StopEmulatio
   s_update_main_frame_event.Set();  // Kick the waiting event
 }
 
+JNIEXPORT void JNICALL
+Java_org_dolphinemu_dolphinemu_NativeLibrary_WaitUntilDoneBooting(JNIEnv* env, jobject obj)
+{
+  Core::WaitUntilDoneBooting();
+}
+
 JNIEXPORT jboolean JNICALL Java_org_dolphinemu_dolphinemu_NativeLibrary_IsRunning(JNIEnv* env,
                                                                                   jobject obj)
 {

Source/Core/Core/Core.cpp

@@ -94,6 +94,7 @@ static bool s_is_stopping = false;
 static bool s_hardware_initialized = false;
 static bool s_is_started = false;
 static Common::Flag s_is_booting;
+static Common::Event s_done_booting;
 static std::thread s_emu_thread;
 static StateChangedCallbackFunc s_on_state_changed_callback;
 
@@ -236,6 +237,8 @@ bool Init(std::unique_ptr<BootParameters> boot, const WindowSystemInfo& wsi)
   g_video_backend->PrepareWindow(wsi);
 
   // Start the emu thread
+  s_done_booting.Reset();
+  s_is_booting.Set();
   s_emu_thread = std::thread(EmuThread, std::move(boot), wsi);
   return true;
 }
@@ -412,11 +415,11 @@ static void FifoPlayerThread(const std::optional<std::string>& savestate_path,
 static void EmuThread(std::unique_ptr<BootParameters> boot, WindowSystemInfo wsi)
 {
   const SConfig& core_parameter = SConfig::GetInstance();
-  s_is_booting.Set();
   if (s_on_state_changed_callback)
     s_on_state_changed_callback(State::Starting);
   Common::ScopeGuard flag_guard{[] {
     s_is_booting.Clear();
+    s_done_booting.Set();
     s_is_started = false;
     s_is_stopping = false;
     s_wants_determinism = false;
@@ -539,6 +542,7 @@ static void EmuThread(std::unique_ptr<BootParameters> boot, WindowSystemInfo wsi
   // The hardware is initialized.
   s_hardware_initialized = true;
   s_is_booting.Clear();
+  s_done_booting.Set();
 
   // Set execution state to known values (CPU/FIFO/Audio Paused)
   CPU::Break();
@@ -662,6 +666,12 @@ State GetState()
   return State::Uninitialized;
 }
 
+void WaitUntilDoneBooting()
+{
+  if (s_is_booting.IsSet() || !s_hardware_initialized)
+    s_done_booting.Wait();
+}
+
 static std::string GenerateScreenshotFolderPath()
 {
   const std::string& gameId = SConfig::GetInstance().GetGameID();

Source/Core/Core/Core.h

@@ -56,6 +56,7 @@ bool WantsDeterminism();
 // [NOT THREADSAFE] For use by Host only
 void SetState(State state);
 State GetState();
+void WaitUntilDoneBooting();
 
 void SaveScreenShot(bool wait_for_completion = false);
 void SaveScreenShot(std::string_view name, bool wait_for_completion = false);