Preserve webchannel and userscripts when restoring history

Most page-state is set in webcontentsadapter::initialize except user
scripts and webchannel. This patch ensures those are initialized too
when changing to a new adapter during history restore.

Change-Id: I4dca23ddab50480b1a72252a038834ce1802ad77
Task-number: QTBUG-50751
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: David Rosca <nowrep@gmail.com>

5 files changed, 63 insertions, 2 deletions

diff --git a/src/webenginewidgets/api/qwebenginepage.cpp b/src/webenginewidgets/api/qwebenginepage.cpp
index 511ddfb0f..b1bf33067 100644
--- a/src/webenginewidgets/api/qwebenginepage.cpp
+++ b/src/webenginewidgets/api/qwebenginepage.cpp
@@ -107,6 +107,7 @@ QWebEnginePagePrivate::QWebEnginePagePrivate(QWebEngineProfile *_profile)
     , m_isBeingAdopted(false)
     , m_backgroundColor(Qt::white)
     , fullscreenMode(false)
+    , webChannel(nullptr)
 {
     memset(actions, 0, sizeof(actions));
 }
@@ -407,8 +408,14 @@ void QWebEnginePagePrivate::recreateFromSerializedHistory(QDataStream &input)
 {
     QExplicitlySharedDataPointer<WebContentsAdapter> newWebContents = WebContentsAdapter::createFromSerializedNavigationHistory(input, this);
     if (newWebContents) {
+        // Keep the old adapter referenced so the user-scripts are not
+        // unregistered immediately.
+        QExplicitlySharedDataPointer<WebContentsAdapter> oldWebContents = adapter;
         adapter = newWebContents.data();
         adapter->initialize(this);
+        if (webChannel)
+            adapter->setWebChannel(webChannel);
+        scriptCollection.d->rebindToContents(adapter.data());
     }
 }
 
@@ -519,7 +526,7 @@ QWebEngineSettings *QWebEnginePage::settings() const
 QWebChannel *QWebEnginePage::webChannel() const
 {
     Q_D(const QWebEnginePage);
-    return d->adapter->webChannel();
+    return d->webChannel;
 }
 
 /*!
@@ -536,7 +543,10 @@ QWebChannel *QWebEnginePage::webChannel() const
 void QWebEnginePage::setWebChannel(QWebChannel *channel)
 {
     Q_D(QWebEnginePage);
-    d->adapter->setWebChannel(channel);
+    if (d->webChannel != channel) {
+        d->webChannel = channel;
+        d->adapter->setWebChannel(channel);
+    }
 }
 
 /*!
diff --git a/src/webenginewidgets/api/qwebenginepage_p.h b/src/webenginewidgets/api/qwebenginepage_p.h
index 9cc4553d1..18110d923 100644
--- a/src/webenginewidgets/api/qwebenginepage_p.h
+++ b/src/webenginewidgets/api/qwebenginepage_p.h
@@ -151,6 +151,7 @@ public:
     bool m_isBeingAdopted;
     QColor m_backgroundColor;
     bool fullscreenMode;
+    QWebChannel *webChannel;
 
     mutable QtWebEngineCore::CallbackDirectory m_callbacks;
     mutable QAction *actions[QWebEnginePage::WebActionCount];
diff --git a/src/webenginewidgets/api/qwebenginescriptcollection.cpp b/src/webenginewidgets/api/qwebenginescriptcollection.cpp
index 9967cde85..117c35b5a 100644
--- a/src/webenginewidgets/api/qwebenginescriptcollection.cpp
+++ b/src/webenginewidgets/api/qwebenginescriptcollection.cpp
@@ -220,3 +220,15 @@ void QWebEngineScriptCollectionPrivate::reserve(int capacity)
 {
     m_scriptController->reserve(m_contents, capacity);
 }
+
+void QWebEngineScriptCollectionPrivate::rebindToContents(QtWebEngineCore::WebContentsAdapter *page)
+{
+    Q_ASSERT(m_contents);
+    Q_ASSERT(page);
+    Q_ASSERT(m_contents != page);
+
+    Q_FOREACH (const UserScript &script, m_scriptController->registeredScripts(m_contents)) {
+        m_scriptController->addUserScript(script, page);
+    }
+    m_contents = page;
+}
diff --git a/src/webenginewidgets/api/qwebenginescriptcollection_p.h b/src/webenginewidgets/api/qwebenginescriptcollection_p.h
index cc6e88445..b5ae60a2c 100644
--- a/src/webenginewidgets/api/qwebenginescriptcollection_p.h
+++ b/src/webenginewidgets/api/qwebenginescriptcollection_p.h
@@ -69,6 +69,8 @@ public:
     QList<QWebEngineScript> toList(const QString &scriptName = QString()) const;
     QWebEngineScript find(const QString & name) const;
 
+    void rebindToContents(QtWebEngineCore::WebContentsAdapter *contents);
+
     void insert(const QWebEngineScript &);
     bool remove(const QWebEngineScript &);
     void clear();
diff --git a/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp b/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
index 8fd71c701..690cf70e4 100644
--- a/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
+++ b/tests/auto/widgets/qwebenginepage/tst_qwebenginepage.cpp
@@ -33,6 +33,7 @@
 #include <QStyle>
 #include <QtTest/QtTest>
 #include <QTextCharFormat>
+#include <QWebChannel>
 #include <private/qinputmethod_p.h>
 #include <qnetworkcookiejar.h>
 #include <qnetworkreply.h>
@@ -42,6 +43,8 @@
 #include <qwebenginehistory.h>
 #include <qwebenginepage.h>
 #include <qwebengineprofile.h>
+#include <qwebenginescript.h>
+#include <qwebenginescriptcollection.h>
 #include <qwebenginesettings.h>
 #include <qwebengineview.h>
 #include <qimagewriter.h>
@@ -237,6 +240,8 @@ private Q_SLOTS:
     void loadInSignalHandlers_data();
     void loadInSignalHandlers();
 
+    void restoreHistory();
+
 private:
     QWebEngineView* m_view;
     QWebEnginePage* m_page;
@@ -5079,5 +5084,36 @@ void tst_QWebEnginePage::loadInSignalHandlers()
     QCOMPARE(m_page->url(), urlForSetter);
 }
 
+void tst_QWebEnginePage::restoreHistory()
+{
+    QWebChannel *channel = new QWebChannel;
+    QWebEnginePage *page = new QWebEnginePage;
+    page->setWebChannel(channel);
+
+    QWebEngineScript script;
+    script.setName(QStringLiteral("script"));
+    page->scripts().insert(script);
+
+    QSignalSpy spy(page, SIGNAL(loadFinished(bool)));
+    page->load(QUrl(QStringLiteral("qrc:/resources/test1.html")));
+    QTRY_COMPARE(spy.count(), 1);
+
+    QCOMPARE(page->webChannel(), channel);
+    QVERIFY(page->scripts().contains(script));
+
+    QByteArray data;
+    QDataStream out(&data, QIODevice::ReadWrite);
+    out << *page->history();
+    QDataStream in(&data, QIODevice::ReadOnly);
+    in >> *page->history();
+    QTRY_COMPARE(spy.count(), 2);
+
+    QCOMPARE(page->webChannel(), channel);
+    QVERIFY(page->scripts().contains(script));
+
+    delete page;
+    delete channel;
+}
+
 QTEST_MAIN(tst_QWebEnginePage)
 #include "tst_qwebenginepage.moc"