svg export: check text hyperlink URLs the same way as shape ones

and have the slideshow open only http, https and mailto links

same check as:

commit 34ec465717
Date:   Mon Mar 4 09:38:02 2019 +0100

    Check svg URLs before exporting

text hyperlinks exported since:

commit b76628acb1
Date:   Sat Aug 11 22:23:22 2012 +0200

    text export support for bullets and hyperlinks

Signed-off-by: Caolán McNamara <caolan.mcnamara@collabora.com>
Change-Id: I826ffb43f0e809f91d1728a9a3b39ebec5b83d6e
Reviewed-on: https://gerrit.collaboraoffice.com/c/online/+/13498
Reviewed-by: Noel Grandin <noel.grandin@collabora.com>
Tested-by: Jenkins CPCI <releng@collaboraoffice.com>
(cherry picked from commit 5f9e522ae9b43a9f4777d86accd20cce02d8fad3)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/211595
Tested-by: Jenkins
Reviewed-by: Xisco Fauli <xiscofauli@libreoffice.org>

filter/source/svg/presentation_engine.js

@@ -16217,7 +16217,17 @@ HyperlinkElement.prototype.handleClick = function( )
         var aWindowObject = document.defaultView;
         if( aWindowObject )
         {
-            aWindowObject.open( this.sURL, this.sId );
+            var sProtocol = '';
+            try
+            {
+                sProtocol = new URL( this.sURL, document.baseURI ).protocol;
+            }
+            catch( e )
+            {
+                log( 'error: HyperlinkElement.handleClick: invalid url.' );
+            }
+            if( sProtocol === 'http:' || sProtocol === 'https:' || sProtocol === 'mailto:' )
+                aWindowObject.open( this.sURL, this.sId );
         }
         else
         {

filter/source/svg/svgwriter.cxx

@@ -37,6 +37,7 @@
 #include <tools/fract.hxx>
 #include <tools/helpers.hxx>
 #include <tools/stream.hxx>
+#include <tools/urlobj.hxx>
 #include <xmloff/namespacemap.hxx>
 #include <xmloff/unointerfacetouniqueidentifiermapper.hxx>
 #include <i18nlangtag/languagetag.hxx>
@@ -1309,7 +1310,15 @@ bool SVGTextWriter::nextTextPortion()
 #if OSL_DEBUG_LEVEL > 0
                                 sInfo += "url: " + mrExport.GetRelativeReference( sURL );
 #endif
-                                msUrl = mrExport.GetRelativeReference( sURL );
+                                // A link to a place in the presentation starts with '#'.
+                                INetURLObject aINetURLObject(sURL);
+                                if (sURL.startsWith("#")
+                                    || (!aINetURLObject.HasError()
+                                        && !aINetURLObject.IsExoticProtocol()
+                                        && aINetURLObject.GetProtocol() != INetProtocol::Javascript))
+                                    msUrl = mrExport.GetRelativeReference( sURL );
+                                else
+                                    msUrl.clear();
                                 if( !msUrl.isEmpty() )
                                 {
                                     implRegisterInterface( xPortionTextRange );