From 9ac73e7ad15de08aab6b1198115be2eb44da7afe Mon Sep 17 00:00:00 2001
From: George Yunaev <gyunaev@ulduzsoft.com>
Date: Fri, 21 May 2021 15:57:21 -0700
Subject: [PATCH] Custom URL scheme registration needs to be applied once per
 https://doc.qt.io/qt-5/qwebengineurlschemehandler.html

---
 src/viewwindow_webengine.cpp | 20 +++++++++++++-------
 src/viewwindow_webengine.h   |  3 ---
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/src/viewwindow_webengine.cpp b/src/viewwindow_webengine.cpp
index 631d84d..34f3396 100644
--- a/src/viewwindow_webengine.cpp
+++ b/src/viewwindow_webengine.cpp
@@ -63,16 +63,22 @@ ViewWindow::ViewWindow( QWidget * parent )
     m_contextMenuLink = 0;
     m_storedScrollbarPosition = -1; // see header
 
-    // Use our network emulation layer. I don't know if we transfer the ownership when we install it,
-    // so we create one per page. May be unnecessary.
-    m_provider = new DataProvider_QWebEngine( this );
-
-    page()->profile()->installUrlSchemeHandler( EBook_CHM::urlScheme(), m_provider );
-    page()->profile()->installUrlSchemeHandler( EBook_EPUB::urlScheme(), m_provider );
-
     // All links are going through us
     //page()->setLinkDelegationPolicy( QWebPage::DelegateAllLinks );
 
+    // This needs to be done only once
+    static bool providerInstalled = false;
+
+    if ( !providerInstalled )
+    {
+        // Use our network emulation layer. We do not transfer the ownership when we install it. See https://doc.qt.io/qt-5/qwebengineurlschemehandler.html
+        DataProvider_QWebEngine * provider = new DataProvider_QWebEngine( 0 );
+
+        QWebEngineProfile::defaultProfile()->installUrlSchemeHandler( EBook_CHM::urlScheme(), provider );
+        QWebEngineProfile::defaultProfile()->installUrlSchemeHandler( EBook_EPUB::urlScheme(), provider );
+        providerInstalled = true;
+    }
+
     connect( this, SIGNAL( loadFinished(bool)), this, SLOT( onLoadFinished(bool)) );
 
     // Search results highlighter
diff --git a/src/viewwindow_webengine.h b/src/viewwindow_webengine.h
index 0adea31..3e96690 100644
--- a/src/viewwindow_webengine.h
+++ b/src/viewwindow_webengine.h
@@ -128,9 +128,6 @@ class ViewWindow : public QWebEngineView
         // It is set to -1 if no scrollbar position has been set and the page is not loaded yet
         // It is set to 0 if no scrollbar position has been set and the page is loaded already
         int						m_storedScrollbarPosition;
-
-        // Data provider
-        DataProvider_QWebEngine * m_provider;
 };
 
 #endif // VIEWWINDOW_WEBENGINE_H
-- 
2.31.1