Better error reporting for QWebEngineUrlScheme

Add warnings for late registration and invalid configuration.

Fixes: QTBUG-72842
Change-Id: I2c103c3b3581112cc885c3a1b4f42c011c3510ab
Reviewed-by: Michal Klocek <michal.klocek@qt.io>

3 files changed, 46 insertions, 6 deletions

diff --git a/src/core/api/qwebengineurlscheme.cpp b/src/core/api/qwebengineurlscheme.cpp
index d63599163..9f7288f2d 100644
--- a/src/core/api/qwebengineurlscheme.cpp
+++ b/src/core/api/qwebengineurlscheme.cpp
@@ -39,7 +39,9 @@
 
 #include "qwebengineurlscheme.h"
 
-#include <url/url_util_qt.h>
+#include "url/url_util_qt.h"
+
+#include <QtDebug>
 
 QT_BEGIN_NAMESPACE
 
@@ -59,6 +61,8 @@ ASSERT_ENUMS_MATCH(QWebEngineUrlScheme::ServiceWorkersAllowed, url::CustomScheme
 ASSERT_ENUMS_MATCH(QWebEngineUrlScheme::ViewSourceAllowed, url::CustomScheme::ViewSourceAllowed)
 ASSERT_ENUMS_MATCH(QWebEngineUrlScheme::ContentSecurityPolicyIgnored, url::CustomScheme::ContentSecurityPolicyIgnored)
 
+static bool g_schemesLocked = false;
+
 class QWebEngineUrlSchemePrivate : public QSharedData
                                  , public url::CustomScheme
 {
@@ -357,6 +361,28 @@ void QWebEngineUrlScheme::setFlags(Flags newValue)
 */
 void QWebEngineUrlScheme::registerScheme(const QWebEngineUrlScheme &scheme)
 {
+    if (scheme.d->name.empty()) {
+        qWarning() << "QWebEngineUrlScheme::registerScheme: Scheme name cannot be empty";
+        return;
+    }
+
+    bool needsPort = scheme.d->has_port_component();
+    bool hasPort = scheme.d->default_port != url::PORT_UNSPECIFIED;
+    if (needsPort && !hasPort) {
+        qWarning() << "QWebEngineUrlScheme::registerScheme: Scheme" << scheme.name() << "needs a default port";
+        return;
+    }
+
+    if (url::CustomScheme::FindScheme(scheme.d->name)) {
+        qWarning() << "QWebEngineUrlScheme::registerScheme: Scheme" << scheme.name() << "already registered";
+        return;
+    }
+
+    if (g_schemesLocked) {
+        qWarning() << "QWebEngineUrlScheme::registerScheme: Too late to register scheme" << scheme.name();
+        return;
+    }
+
     url::CustomScheme::AddScheme(*scheme.d);
 }
 
@@ -374,4 +400,9 @@ QWebEngineUrlScheme QWebEngineUrlScheme::schemeByName(const QByteArray &name)
     return QWebEngineUrlScheme();
 }
 
+void QWebEngineUrlScheme::lockSchemes()
+{
+    g_schemesLocked = true;
+}
+
 QT_END_NAMESPACE
diff --git a/src/core/api/qwebengineurlscheme.h b/src/core/api/qwebengineurlscheme.h
index 88a8f5065..da3010335 100644
--- a/src/core/api/qwebengineurlscheme.h
+++ b/src/core/api/qwebengineurlscheme.h
@@ -46,6 +46,8 @@
 #include <QtCore/qobjectdefs.h>
 #include <QtCore/qshareddata.h>
 
+namespace QtWebEngineCore { class WebEngineContext; }
+
 QT_BEGIN_NAMESPACE
 
 class QWebEngineUrlSchemePrivate;
@@ -106,6 +108,8 @@ public:
     static QWebEngineUrlScheme schemeByName(const QByteArray &name);
 
 private:
+    friend QtWebEngineCore::WebEngineContext;
+    static void lockSchemes();
     QWebEngineUrlScheme(QWebEngineUrlSchemePrivate *d);
     QSharedDataPointer<QWebEngineUrlSchemePrivate> d;
 };
diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index ca52a5e67..edae5c47d 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -353,11 +353,16 @@ WebEngineContext::WebEngineContext()
     qputenv("force_s3tc_enable", "true");
 #endif
 
-    QWebEngineUrlScheme qrcScheme(QByteArrayLiteral("qrc"));
-    qrcScheme.setFlags(QWebEngineUrlScheme::SecureScheme
-                       | QWebEngineUrlScheme::LocalAccessAllowed
-                       | QWebEngineUrlScheme::ViewSourceAllowed);
-    QWebEngineUrlScheme::registerScheme(qrcScheme);
+    if (QWebEngineUrlScheme::schemeByName(QByteArrayLiteral("qrc")) == QWebEngineUrlScheme()) {
+        // User might have registered "qrc" already with different options.
+        QWebEngineUrlScheme qrcScheme(QByteArrayLiteral("qrc"));
+        qrcScheme.setFlags(QWebEngineUrlScheme::SecureScheme
+                           | QWebEngineUrlScheme::LocalAccessAllowed
+                           | QWebEngineUrlScheme::ViewSourceAllowed);
+        QWebEngineUrlScheme::registerScheme(qrcScheme);
+    }
+
+    QWebEngineUrlScheme::lockSchemes();
 
     // Allow us to inject javascript like any webview toolkit.
     content::RenderFrameHost::AllowInjectingJavaScriptForAndroidWebView();