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Support cascaded java callbacks in Edge #1919 #2019

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Merged
merged 1 commit into from
Apr 15, 2025
Merged

Support cascaded java callbacks in Edge #1919 #2019

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15 changes: 9 additions & 6 deletions bundles/org.eclipse.swt/Eclipse SWT Browser/win32/org/eclipse/swt/browser/Edge.java
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Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ public WebViewEnvironment(ICoreWebView2Environment environment) {

WebViewEnvironment containingEnvironment;

static boolean inCallback;
static int inCallback;
boolean inNewWindow;
private boolean inEvaluate;
HashMap<Long, LocationEvent> navigations = new HashMap<>();
Expand Down Expand Up @@ -235,11 +235,11 @@ static void error(int code, int hr) {

static IUnknown newCallback(ICoreWebView2SwtCallback handler) {
long punk = COM.CreateSwtWebView2Callback((arg0, arg1) -> {
inCallback = true;
inCallback++;
try {
return handler.Invoke(arg0, arg1);
} finally {
inCallback = false;
inCallback--;
}
});
if (punk == 0) error(SWT.ERROR_NO_HANDLES, COM.E_OUTOFMEMORY);
Expand Down Expand Up @@ -552,7 +552,7 @@ void checkDeadlock() {
// and JavaScript callbacks are serialized. An event handler waiting
// for a completion of another handler will deadlock. Detect this
// situation and throw an exception instead.
if (inCallback || inNewWindow) {
if (inCallback > 0 || inNewWindow) {
SWT.error(SWT.ERROR_FAILED_EVALUATE, null, " [WebView2: deadlock detected]");
}
}
Expand Down Expand Up @@ -821,7 +821,7 @@ void browserDispose(Event event) {
if(controller != null) {
// Bug in WebView2. Closing the controller from an event handler results
// in a crash. The fix is to delay the closure with asyncExec.
if (inCallback) {
if (inCallback > 0) {
ICoreWebView2Controller controller1 = controller;
controller.put_IsVisible(false);
browser.getDisplay().asyncExec(() -> {
Expand Down Expand Up @@ -916,7 +916,7 @@ public Object evaluate(String script) throws SWTException {
// Feature in WebView2. ExecuteScript works regardless of IsScriptEnabled setting.
// Disallow programmatic execution manually.
if (!jsEnabled) return null;
if(inCallback) {
if(inCallback > 0) {
// Execute script, but do not wait for async call to complete as otherwise it
// can cause a deadlock if execute inside a WebView callback.
execute(script);
Expand Down Expand Up @@ -1017,12 +1017,15 @@ long handleCallJava(int index, long bstrToken, long bstrArgsJson) {
String token = bstrToString(bstrToken);
BrowserFunction function = functions.get(index);
if (function != null && token.equals (function.token)) {
inCallback++;
try {
String argsJson = bstrToString(bstrArgsJson);
Object args = JSON.parse(argsJson.toCharArray());
result = function.function ((Object[]) args);
} catch (Throwable e) {
result = WebBrowser.CreateErrorString(e.getLocalizedMessage());
} finally {
inCallback--;
}
}
String json = JSON.stringify(result);
Expand Down
55 changes: 55 additions & 0 deletions ...t.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2247,6 +2247,61 @@ function callCustomFunction() {
assertTrue(message, passed);
}

/**
* Test for stacked (cascaded) calls between Java and JS i.e. java calls JS
* which calls Java which calls JS and so on.
*
* @see https://github.com/eclipse-platform/eclipse.platform.swt/issues/1919
*
*/
@Test
public void test_BrowserFunction_callback_stackedCalls() {
assumeFalse("Not currently working on Linux, see https://github.com/eclipse-platform/eclipse.platform.swt/issues/2021", SwtTestUtil.isGTK);
AtomicInteger javaCallbackExecuted = new AtomicInteger();
final int DEPTH = 5;

class DeepJavascriptCallback extends BrowserFunction { // Note: Local class defined inside method.
DeepJavascriptCallback(Browser browser, String name) {
super(browser, name);
}

@Override
public Object function(Object[] arguments) {
if (javaCallbackExecuted.get() < DEPTH) {
javaCallbackExecuted.incrementAndGet();
browser.evaluate("jsCallbackToJava();");
}

return null;
}
}

// Define a javascript function and call it
String htmlWithScript = """
<html><head>
<script language="JavaScript">
function callCustomFunction() {
document.body.style.backgroundColor = 'red'
jsCallbackToJava()
}

</script>
</head>
<body> Going to make a callback to Java </body>
</html>
""";

browser.setText(htmlWithScript);
new DeepJavascriptCallback(browser, "jsCallbackToJava");

browser.addProgressListener(callCustomFunctionUponLoad);

shell.open();
boolean passed = waitForPassCondition(() -> javaCallbackExecuted.get() == DEPTH);
String message = "Java failed to get a callback from javascript. Test timed out";
assertTrue(message, passed);
}

/**
* Test that javascript can call java and pass an integer to java.
* loosely based on Snippet307.
Expand Down
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