wasm: clarify qtloader onExit behavior

onExit is called whenever the application exits, i.e.
when the app canvas should no longer be displayed and
the loader/embedder code should take some action.

Emscripten provides two callbacks which can be used
here:
  - onExit, called when the app exits (but see EXIT_RUNTIME)
  - onAbort, called on abort errors.

These map to the two cases Qt's onExit supports. onExit
is not called when EXIT_RUNTIME is disabled, which means
we don't need the special case for exit code 0.

In addition call onExit on any exception. The second
call to showUi() in html_shell.html is then not needed
any more and we avoid duplicating the UI state handling
in user code.

Update the qtloader_integration test to handle changes in
behavior (we no longer set the error text on exit). Use
emscripten_force_exit() to simulate application exit -
using this function makes Emscripten call onExit even
when EXIT_RUNTIME is disabled.

Pick-to: 6.6
Change-Id: I72b5463c1836e8d5054e594abbd304fbc67032b7
Reviewed-by: Piotr Wierciński <piotr.wiercinski@qt.io>
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>

2 files changed, 5 insertions, 7 deletions

diff --git a/tests/manual/wasm/qtloader_integration/main.cpp b/tests/manual/wasm/qtloader_integration/main.cpp
index b9bed0d49b..ee032e9952 100644
--- a/tests/manual/wasm/qtloader_integration/main.cpp
+++ b/tests/manual/wasm/qtloader_integration/main.cpp
@@ -71,7 +71,7 @@ void crash()
 
 void exitApp()
 {
-    exit(ExitValueFromExitApp);
+    emscripten_force_exit(ExitValueFromExitApp);
 }
 
 void produceOutput()
@@ -135,7 +135,7 @@ int main(int argc, char **argv)
             std::find(arguments.begin(), arguments.end(), QStringLiteral("--exit-immediately"))
             != arguments.end();
     if (exitImmediately)
-        return ExitValueImmediateReturn;
+        emscripten_force_exit(ExitValueImmediateReturn);
 
     const bool crashImmediately =
             std::find(arguments.begin(), arguments.end(), QStringLiteral("--crash-immediately"))
diff --git a/tests/manual/wasm/qtloader_integration/test_body.js b/tests/manual/wasm/qtloader_integration/test_body.js
index 233c64f2f6..f1285d617a 100644
--- a/tests/manual/wasm/qtloader_integration/test_body.js
+++ b/tests/manual/wasm/qtloader_integration/test_body.js
@@ -345,9 +345,7 @@ export class QtLoaderIntegrationTests
             caughtException = e;
         }
 
-        // An exception should have been thrown from load()
-        assert.equal('RuntimeError', caughtException.name);
-
+        assert.isUndefined(caughtException);
         assert.equal(1, onExitMock.calls.length);
         const exitStatus = onExitMock.calls[0][0];
         assert.isTrue(exitStatus.crashed);
@@ -395,7 +393,7 @@ export class QtLoaderIntegrationTests
         const exitStatus = onExitMock.calls[0][0];
         assert.isFalse(exitStatus.crashed);
         assert.equal(instance.EXIT_VALUE_FROM_EXIT_APP, exitStatus.code);
-        assert.isNotUndefined(exitStatus.text);
+        assert.isUndefined(exitStatus.text);
     }
 
     async exitImmediately()
@@ -414,7 +412,7 @@ export class QtLoaderIntegrationTests
 
         assert.isFalse(exitStatusFromOnExit.crashed);
         assert.equal(instance.EXIT_VALUE_IMMEDIATE_RETURN, exitStatusFromOnExit.code);
-        assert.isNotUndefined(exitStatusFromOnExit.text);
+        assert.isUndefined(exitStatusFromOnExit.text);
     }
 
     async userQuitCallbackCalled()