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.

Change-Id: I72b5463c1836e8d5054e594abbd304fbc67032b7
Reviewed-by: Piotr Wierciński <piotr.wiercinski@qt.io>
Reviewed-by: Mikołaj Boc <Mikolaj.Boc@qt.io>
(cherry picked from commit a4d1c30a1b)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Morten Sørvig 2023-07-05 14:46:13 +02:00 committed by Qt Cherry-pick Bot
parent 2b62922e2e
commit e3b08a61eb
4 changed files with 32 additions and 36 deletions

View File

@ -9,9 +9,14 @@
* - environment: { [name:string] : string }
* environment variables set on the instance
* - onExit: (exitStatus: { text: string, code?: number, crashed: bool }) => void
* called when the application has exited for any reason. exitStatus.code is defined in
* case of a normal application exit. This is not called on exit with return code 0, as
* the program does not shutdown its runtime and technically keeps running async.
* called when the application has exited for any reason. There are two cases:
* aborted: crashed is true, text contains an error message.
* exited: crashed is false, code contians the exit code.
*
* Note that by default Emscripten does not exit when main() returns. This behavior
* is controlled by the EXIT_RUNTIME linker flag; set "-s EXIT_RUNTIME=1" to make
* Emscripten tear down the runtime and exit when main() returns.
*
* - containerElements: HTMLDivElement[]
* Array of host elements for Qt screens. Each of these elements is mapped to a QScreen on
* launch.
@ -161,26 +166,14 @@ async function qtLoad(config)
return originalLocatedFilename;
}
// This is needed for errors which occur right after resolving the instance promise but
// before exiting the function (i.e. on call to main before stack unwinding).
let loadTimeException = undefined;
// We don't want to issue onExit when aborted
let aborted = false;
const originalQuit = config.quit;
config.quit = (code, exception) =>
{
originalQuit?.(code, exception);
if (exception)
loadTimeException = exception;
if (!aborted && code !== 0) {
config.qt.onExit?.({
text: exception.message,
code,
crashed: false
});
}
};
const originalOnExit = config.onExit;
config.onExit = code => {
originalOnExit?.();
config.qt.onExit?.({
code,
crashed: false
});
}
const originalOnAbort = config.onAbort;
config.onAbort = text =>
@ -212,10 +205,17 @@ async function qtLoad(config)
// Call app/emscripten module entry function. It may either come from the emscripten
// runtime script or be customized as needed.
const instance = await Promise.race(
[circuitBreaker, config.qt.entryFunction(config)]);
if (loadTimeException && loadTimeException.name !== 'ExitStatus')
throw loadTimeException;
let instance;
try {
instance = await Promise.race(
[circuitBreaker, config.qt.entryFunction(config)]);
} catch (e) {
config.qt.onExit?.({
text: e.message,
crashed: true
});
throw e;
}
return instance;
}

View File

@ -65,8 +65,6 @@
} catch (e) {
console.error(e);
console.error(e.stack);
status.innerHTML = e.message;
showUi(spinner);
}
}
</script>

View File

@ -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"))

View File

@ -323,9 +323,7 @@ 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);
@ -373,7 +371,7 @@ 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()
@ -392,7 +390,7 @@ 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()