sw: fix not needed invalidation of title field on each keypress

Type a character, SwDocShell::DoFlushDocInfo() is called because the
number of characters changed, and that rapaints all title fields.

This happens as SwFormatField::UpdateTextNode() calls
SwTextField::ExpandTextField() with bForceNotify=true, because that was
needed for conditional text in commit
cd94a84b89c476760ad74bf088a5d6f8ba4ce209 (125044: - use field's content
cache on <SwTxtFld> construction only, 2014-06-13).

Fix the problem by not forcing notifications for title fields in
SwFormatField::UpdateTextNode(): SwTextField::ExpandTextField() will
send a notification if the expend result differs without forcing as
well.

Change-Id: I5e46ab6aef33ff5e348d40b8644bcc9cf353c326
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115743
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>
Tested-by: Jenkins

3 files changed, 111 insertions, 1 deletions

diff --git a/sw/qa/core/txtnode/data/title-field-invalidate.fodt b/sw/qa/core/txtnode/data/title-field-invalidate.fodt
new file mode 100644
index 000000000000..e47129538fa9
--- /dev/null
+++ b/sw/qa/core/txtnode/data/title-field-invalidate.fodt
@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<office:document xmlns:text="urn:oasis:names:tc:opendocument:xmlns:text:1.0" xmlns:style="urn:oasis:names:tc:opendocument:xmlns:style:1.0" xmlns:meta="urn:oasis:names:tc:opendocument:xmlns:meta:1.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:fo="urn:oasis:names:tc:opendocument:xmlns:xsl-fo-compatible:1.0" xmlns:office="urn:oasis:names:tc:opendocument:xmlns:office:1.0" office:mimetype="application/vnd.oasis.opendocument.text">
+  <office:meta>
+    <dc:title>mytitle</dc:title>
+  </office:meta>
+  <office:automatic-styles>
+    <style:page-layout style:name="pm1">
+      <style:page-layout-properties fo:page-width="14.8cm" fo:page-height="21.0cm" fo:margin-top="2cm" fo:margin-bottom="2cm" fo:margin-left="2cm" fo:margin-right="2cm"/>
+    </style:page-layout>
+  </office:automatic-styles>
+  <office:master-styles>
+    <style:master-page style:name="Standard" style:display-name="Standard" style:page-layout-name="pm1" style:next-style-name="Standard">
+      <style:footer>
+        <text:p><text:title>mytitle</text:title></text:p>
+      </style:footer>
+    </style:master-page>
+  </office:master-styles>
+  <office:body>
+    <office:text>
+      <text:p>body text</text:p>
+    </office:text>
+  </office:body>
+</office:document>
diff --git a/sw/qa/core/txtnode/txtnode.cxx b/sw/qa/core/txtnode/txtnode.cxx
index a4c7baed8492..f4bb070ac972 100644
--- a/sw/qa/core/txtnode/txtnode.cxx
+++ b/sw/qa/core/txtnode/txtnode.cxx
@@ -9,8 +9,13 @@
 
 #include <swmodeltestbase.hxx>
 
+#include <LibreOfficeKit/LibreOfficeKitEnums.h>
+#include <comphelper/lok.hxx>
+#include <sfx2/viewsh.hxx>
 #include <vcl/gdimtf.hxx>
+#include <vcl/scheduler.hxx>
 
+#include <IDocumentStatistics.hxx>
 #include <fmtanchr.hxx>
 #include <frameformats.hxx>
 #include <wrtsh.hxx>
@@ -84,6 +89,71 @@ CPPUNIT_TEST_FIXTURE(SwCoreTxtnodeTest, testTextBoxNodeSplit)
     pWrtShell->SplitNode();
 }
 
+namespace
+{
+struct ViewCallback
+{
+    int m_nInvalidations = 0;
+
+    static void callback(int nType, const char* pPayload, void* pData);
+    void callbackImpl(int nType, const char* pPayload);
+};
+
+void ViewCallback::callback(int nType, const char* pPayload, void* pData)
+{
+    static_cast<ViewCallback*>(pData)->callbackImpl(nType, pPayload);
+}
+
+void ViewCallback::callbackImpl(int nType, const char* /*pPayload*/)
+{
+    switch (nType)
+    {
+        case LOK_CALLBACK_INVALIDATE_TILES:
+        {
+            ++m_nInvalidations;
+        }
+        break;
+    }
+}
+}
+
+CPPUNIT_TEST_FIXTURE(SwCoreTxtnodeTest, testTitleFieldInvalidate)
+{
+    // Set up LOK to track invalidations.
+    comphelper::LibreOfficeKit::setActive(true);
+
+    // Given a document with a title field:
+    load(DATA_DIRECTORY, "title-field-invalidate.fodt");
+    SwXTextDocument* pTextDoc = dynamic_cast<SwXTextDocument*>(mxComponent.get());
+    pTextDoc->initializeForTiledRendering({});
+    SwDocShell* pShell = pTextDoc->GetDocShell();
+    SwDoc* pDoc = pShell->GetDoc();
+    SwWrtShell* pWrtShell = pShell->GetWrtShell();
+    pWrtShell->SttEndDoc(/*bStt=*/false);
+    ViewCallback aCallback;
+    pWrtShell->GetSfxViewShell()->registerLibreOfficeKitViewCallback(&ViewCallback::callback,
+                                                                     &aCallback);
+    Scheduler::ProcessEventsToIdle();
+    aCallback.m_nInvalidations = 0;
+
+    // When typing to the document:
+    pWrtShell->Insert("x");
+
+    // Then make sure that only the text frame at the cursor is invalidated:
+    pDoc->getIDocumentStatistics().GetUpdatedDocStat(/*bCompleteAsync=*/true, /*bFields=*/false);
+    // Without the accompanying fix in place, this test would have failed with:
+    // - Expected: 1
+    // - Actual  : 2
+    // i.e. the footer was also invalidated on each keypress.
+    CPPUNIT_ASSERT_EQUAL(1, aCallback.m_nInvalidations);
+
+    // Tear down LOK.
+    pWrtShell->GetSfxViewShell()->registerLibreOfficeKitViewCallback(nullptr, nullptr);
+    mxComponent->dispose();
+    mxComponent.clear();
+    comphelper::LibreOfficeKit::setActive(false);
+}
+
 CPPUNIT_PLUGIN_IMPLEMENT();
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sw/source/core/txtnode/atrfld.cxx b/sw/source/core/txtnode/atrfld.cxx
index 558874ad1784..089f35c188d6 100644
--- a/sw/source/core/txtnode/atrfld.cxx
+++ b/sw/source/core/txtnode/atrfld.cxx
@@ -377,7 +377,24 @@ void SwFormatField::UpdateTextNode(const SfxPoolItem* pOld, const SfxPoolItem* p
         pTextNd->TriggerNodeUpdate(sw::LegacyModifyHint(pNodeOld, pNodeNew));
     if(bExpand)
     {
-        mpTextField->ExpandTextField( pOld == nullptr && pNew == nullptr );
+        bool bForceNotify = pOld == nullptr && pNew == nullptr;
+        if (bForceNotify)
+        {
+            // Force notify was added for conditional text fields, at least the title fields needs
+            // no forced notify.
+            const SwField* pField = mpTextField->GetFormatField().GetField();
+            const SwFieldIds nWhich = pField->GetTyp()->Which();
+            if (nWhich == SwFieldIds::DocInfo)
+            {
+                auto pDocInfoField = static_cast<const SwDocInfoField*>(pField);
+                if (pDocInfoField->GetSubType() == nsSwDocInfoSubType::DI_TITLE)
+                {
+                    bForceNotify = false;
+                }
+            }
+        }
+
+        mpTextField->ExpandTextField(bForceNotify);
     }
 }