Define the new page callback for interrupting a long-running JavaScript

Issues:
https://github.com/ariya/phantomjs/issues/11198
https://github.com/ariya/phantomjs/issues/11183
https://github.com/ariya/phantomjs/issues/11189

src/modules/webpage.js

@@ -468,6 +468,9 @@ function decorateNewPage(opts, page) {
     // @see https://developer.mozilla.org/en/DOM/window.prompt
     definePageCallbackHandler(page, handlers, "onPrompt", "_getJsPromptCallback");
 
+    // Calls from within the page when some javascript code running to long
+    definePageCallbackHandler(page, handlers, "onLongRunningScript", "_getJsInterruptCallback");
+
     page.event = {};
     page.event.modifier = {
         shift:  0x02000000,

src/webpage.cpp

@@ -112,7 +112,14 @@ public:
 
 public slots:
     bool shouldInterruptJavaScript() {
-        QApplication::processEvents(QEventLoop::AllEvents, 42);
+        m_webPage->javascriptInterrupt();
+
+        if (m_webPage->m_shouldInterruptJs) {
+
+            // reset our flag
+            m_webPage->m_shouldInterruptJs = false;
+            return true;
+        }
         return false;
     }
 
@@ -251,6 +258,7 @@ public:
         , m_filePickerCallback(NULL)
         , m_jsConfirmCallback(NULL)
         , m_jsPromptCallback(NULL)
+        , m_jsInterruptCallback(NULL)
     {
     }
 
@@ -290,6 +298,15 @@ public:
         return m_jsPromptCallback;
     }
     
+    QObject *getJsInterruptCallback() {
+        qDebug() << "WebpageCallbacks - getJsInterruptCallback";
+
+        if (!m_jsInterruptCallback) {
+            m_jsInterruptCallback = new Callback(this);
+        }
+        return m_jsInterruptCallback;
+    }
+
 public slots:
     QVariant call(const QVariantList &arguments) {
         if (m_genericCallback) {
@@ -303,6 +320,7 @@ private:
     Callback *m_filePickerCallback;
     Callback *m_jsConfirmCallback;
     Callback *m_jsPromptCallback;
+    Callback *m_jsInterruptCallback;
 
     friend class WebPage;
 };
@@ -314,6 +332,7 @@ WebPage::WebPage(QObject *parent, const QUrl &baseUrl)
     , m_mousePos(QPoint(0, 0))
     , m_ownsPages(true)
     , m_loadingProgress(0)
+    , m_shouldInterruptJs(false)
 {
     setObjectName("WebPage");
     m_callbacks = new WebpageCallbacks(this);
@@ -729,6 +748,17 @@ bool WebPage::javaScriptPrompt(const QString &msg, const QString &defaultValue,
     return false;
 }
 
+void WebPage::javascriptInterrupt()
+{
+    if (m_callbacks->m_jsInterruptCallback) {
+        QVariant res = m_callbacks->m_jsInterruptCallback->call(QVariantList());
+
+        if (res.canConvert<bool>()) {
+            m_shouldInterruptJs = res.toBool();
+        }
+    }
+}
+
 void WebPage::finish(bool ok)
 {
     QString status = ok ? "success" : "fail";
@@ -1293,6 +1323,15 @@ QObject *WebPage::_getJsPromptCallback()
     return m_callbacks->getJsPromptCallback();
 }
 
+QObject *WebPage::_getJsInterruptCallback()
+{
+    if (!m_callbacks) {
+        m_callbacks = new WebpageCallbacks(this);
+    }
+
+    return m_callbacks->getJsInterruptCallback();
+}
+
 void WebPage::sendEvent(const QString &type, const QVariant &arg1, const QVariant &arg2, const QString &mouseButton, const QVariant &modifierArg)
 {
     Qt::KeyboardModifiers keyboardModifiers(modifierArg.toInt());
@@ -1580,4 +1619,9 @@ void WebPage::updateLoadingProgress(int progress)
     m_loadingProgress = progress;
 }
 
+void WebPage::stopJavaScript()
+{
+    m_shouldInterruptJs = true;
+}
+
 #include "webpage.moc"

src/webpage.h

@@ -258,6 +258,7 @@ public slots:
     QObject *_getFilePickerCallback();
     QObject *_getJsConfirmCallback();
     QObject *_getJsPromptCallback();
+    QObject *_getJsInterruptCallback();
     void _uploadFile(const QString &selector, const QStringList &fileNames);
     void sendEvent(const QString &type, const QVariant &arg1 = QVariant(), const QVariant &arg2 = QVariant(), const QString &mouseButton = QString(), const QVariant &modifierArg = QVariant());
 
@@ -459,6 +460,8 @@ public slots:
      */
     void stop();
 
+    void stopJavaScript();
+
 signals:
     void initialized();
     void loadStarted();
@@ -497,6 +500,7 @@ private:
     QString filePicker(const QString &oldFile);
     bool javaScriptConfirm(const QString &msg);
     bool javaScriptPrompt(const QString &msg, const QString &defaultValue, QString *result);
+    void javascriptInterrupt();
 
 private:
     CustomPage *m_customWebPage;
@@ -513,6 +517,7 @@ private:
     QPoint m_mousePos;
     bool m_ownsPages;
     int m_loadingProgress;
+    bool m_shouldInterruptJs;
 
     friend class Phantom;
     friend class CustomPage;

test/webpage-spec-frames/forever.html

@@ -0,0 +1,12 @@
+<html>
+<head>
+<script type="text/javascript">
+    function forever() {
+        while(true) {}
+    }
+</script>
+</head>
+<body onload="forever();">
+
+</body>
+</html>

test/webpage-spec.js

@@ -1307,6 +1307,18 @@ describe("WebPage object", function() {
             server.close();
         });
     });
+
+    it("should interrupt a long-running JavaScript code", function() {
+        var page = new WebPage();
+        
+        page.onLongRunningScript = function() {
+            page.stopJavaScript();
+        };
+        
+        page.open('../test/webpage-spec-frames/forever.html', function(status) {
+            expect(status).toEqual('success');
+        });
+    });
 });
 
 describe("WebPage construction with options", function () {