tdf#139991: move 0-byte file handling to SfxFrameLoader_Impl::load

This centralizes the code that handles templates, and allows the empty
files to use default templates.

This partially reverts commits:

ada07f303e7cd1e39c73abe0741aefe7d9d73a57
Author Miklos Vajna <vmiklos@collabora.com>
Date   Wed Oct 28 14:54:52 2020 +0100
tdf#123476 filter: try to detect 0-byte files based on extension

2854362f429e476d4a1ab4759c6a1f1c04150280
Author Mike Kaganski <mike.kaganski@collabora.com>
Date   Wed Jan 27 16:05:54 2021 +0100
tdf#123476 filter: Also handle empty ODF

dff586735b6618d9b011823594a33287d8f7f223
Author Mike Kaganski <mike.kaganski@collabora.com>
Date   Mon May 03 17:04:04 2021 +0200
tdf#123476: also use filter by extension when its service is the same

The unit tests from these commits are retained and extended for templates.

Change-Id: I755738d2d5a6d6955d84d6e12f3accc017e0391f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/132938
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

2 files changed, 63 insertions, 9 deletions

diff --git a/sfx2/source/doc/objstor.cxx b/sfx2/source/doc/objstor.cxx
index 0000a9b4f6df..0dc8cb2d1d5b 100644
--- a/sfx2/source/doc/objstor.cxx
+++ b/sfx2/source/doc/objstor.cxx
@@ -429,7 +429,7 @@ bool SfxObjectShell::InitNew( const uno::Reference< embed::XStorage >& xStorage
 
 bool SfxObjectShell::Load( SfxMedium& rMedium )
 {
-    return GeneralInit_Impl(rMedium.GetStorage(), !tools::isEmptyFileUrl(rMedium.GetName()));
+    return GeneralInit_Impl(rMedium.GetStorage(), true);
 }
 
 void SfxObjectShell::DoInitUnitTest()
@@ -662,9 +662,7 @@ bool SfxObjectShell::DoLoad( SfxMedium *pMed )
                     bWarnMediaTypeFallback = false;
                 }
 
-                if (bWarnMediaTypeFallback
-                    || (!tools::isEmptyFileUrl(pMedium->GetName())
-                        && !xStorage->getElementNames().hasElements()))
+                if (bWarnMediaTypeFallback || !xStorage->getElementNames().hasElements())
                     SetError(ERRCODE_IO_BROKENPACKAGE);
             }
             catch( uno::Exception& )
@@ -2260,11 +2258,7 @@ bool SfxObjectShell::ImportFrom(SfxMedium& rMedium,
 
             // #i119492# During loading, some OLE objects like chart will be set
             // modified flag, so needs to reset the flag to false after loading
-            bool bRtn = true;
-            if (!tools::isEmptyFileUrl(rMedium.GetName()))
-            {
-                bRtn = xLoader->filter(aArgs);
-            }
+            bool bRtn = xLoader->filter(aArgs);
             const uno::Sequence < OUString > aNames = GetEmbeddedObjectContainer().GetObjectNames();
             for ( const auto& rName : aNames )
             {
diff --git a/sfx2/source/view/frmload.cxx b/sfx2/source/view/frmload.cxx
index 91b045b2f1a3..bd0329fb2ac3 100644
--- a/sfx2/source/view/frmload.cxx
+++ b/sfx2/source/view/frmload.cxx
@@ -21,6 +21,7 @@
 #include <sfx2/app.hxx>
 #include <sfx2/bindings.hxx>
 #include <sfx2/docfac.hxx>
+#include <sfx2/docfile.hxx>
 #include <sfx2/docfilt.hxx>
 #include <sfx2/doctempl.hxx>
 #include <sfx2/fcontnr.hxx>
@@ -55,8 +56,11 @@
 #include <rtl/ref.hxx>
 #include <sal/log.hxx>
 #include <svl/eitem.hxx>
+#include <svl/stritem.hxx>
 #include <unotools/moduleoptions.hxx>
 #include <tools/diagnose_ex.h>
+#include <tools/stream.hxx>
+#include <tools/urlobj.hxx>
 #include <vcl/svapp.hxx>
 
 using namespace com::sun::star;
@@ -585,6 +589,25 @@ Reference< XController2 > SfxFrameLoader_Impl::impl_createDocumentView( const Re
     return xController;
 }
 
+std::shared_ptr<const SfxFilter> getEmptyURLFilter(const OUString& sURL)
+{
+    INetURLObject aParser(sURL);
+    const OUString aExt = aParser.getExtension(INetURLObject::LAST_SEGMENT, true,
+                                               INetURLObject::DecodeMechanism::WithCharset);
+    const SfxFilterMatcher& rMatcher = SfxGetpApp()->GetFilterMatcher();
+
+    // Requiring the export+preferred flags helps to find the relevant filter, e.g. .doc -> WW8 (and
+    // not WW6 or Mac_Word).
+    std::shared_ptr<const SfxFilter> pFilter = rMatcher.GetFilter4Extension(
+        aExt, SfxFilterFlags::IMPORT | SfxFilterFlags::EXPORT | SfxFilterFlags::PREFERED);
+    if (!pFilter)
+    {
+        // retry without PREFERED so we can find at least something for 0-byte *.ods
+        pFilter
+            = rMatcher.GetFilter4Extension(aExt, SfxFilterFlags::IMPORT | SfxFilterFlags::EXPORT);
+    }
+    return pFilter;
+}
 
 sal_Bool SAL_CALL SfxFrameLoader_Impl::load( const Sequence< PropertyValue >& rArgs,
                                              const Reference< XFrame >& _rTargetFrame )
@@ -608,6 +631,7 @@ sal_Bool SAL_CALL SfxFrameLoader_Impl::load( const Sequence< PropertyValue >& rA
     // check for factory URLs to create a new doc, instead of loading one
     const OUString sURL = aDescriptor.getOrDefault( "URL", OUString() );
     const bool bIsFactoryURL = sURL.startsWith( "private:factory/" );
+    std::shared_ptr<const SfxFilter> pEmptyURLFilter;
     bool bInitNewModel = bIsFactoryURL;
     const bool bIsDefault = bIsFactoryURL && !bExternalModel;
     if (!aDescriptor.has("Replaceable"))
@@ -640,6 +664,28 @@ sal_Bool SAL_CALL SfxFrameLoader_Impl::load( const Sequence< PropertyValue >& rA
     {
         // compatibility
         aDescriptor.put( "FileName", aDescriptor.get( "URL" ) );
+
+        if (!bIsFactoryURL && !bExternalModel && tools::isEmptyFileUrl(sURL))
+        {
+            pEmptyURLFilter = getEmptyURLFilter(sURL);
+            if (pEmptyURLFilter)
+            {
+                aDescriptor.put("DocumentService", pEmptyURLFilter->GetServiceName());
+                if (impl_determineTemplateDocument(aDescriptor))
+                {
+                    // if the media descriptor allowed us to determine a template document
+                    // to create the new document from, then do not init a new document model
+                    // from scratch (below), but instead load the template document
+                    bInitNewModel = false;
+                    // Do not try to load from empty UCB content
+                    aDescriptor.remove("UCBContent");
+                }
+                else
+                {
+                    bInitNewModel = true;
+                }
+            }
+        }
     }
 
     bool bLoadSuccess = false;
@@ -692,6 +738,20 @@ sal_Bool SAL_CALL SfxFrameLoader_Impl::load( const Sequence< PropertyValue >& rA
         const SfxObjectShellRef xDoc = impl_findObjectShell( xModel );
         ENSURE_OR_THROW( xDoc.is(), "no SfxObjectShell for the given model" );
 
+        if (pEmptyURLFilter)
+        {
+            // Detach the medium from the template, and set proper document name and filter
+            auto pMedium = xDoc->GetMedium();
+            auto pItemSet = pMedium->GetItemSet();
+            pItemSet->ClearItem(SID_TEMPLATE);
+            pItemSet->Put(SfxStringItem(SID_FILTER_NAME, pEmptyURLFilter->GetFilterName()));
+            pMedium->SetName(sURL, true);
+            pMedium->SetFilter(pEmptyURLFilter);
+            pMedium->GetInitFileDate(true);
+            xDoc->SetLoading(SfxLoadedFlags::NONE);
+            xDoc->FinishedLoading();
+        }
+
         // ensure the ID of the to-be-created view is in the descriptor, if possible
         const SfxInterfaceId nViewId = impl_determineEffectiveViewId_nothrow( *xDoc, aDescriptor );
         const sal_Int16 nViewNo = xDoc->GetFactory().GetViewNo_Impl( nViewId, 0 );