SwEditWin::SetCursorTwipPosition: support creating a selection

The Android LOK client always creates a text selection by double
clicking on a word, and then the start/end of the selection can be
adjusted using handles.  In the GTK LOK client, it makes sense to allow
the desktop-style selection, where you click somewhere, move the mouse
and finally release the mouse to create a selection. That can be mapped
to settextselect-reset on mouse-down, and settextselect-end on
mouse-move easily.

The only problem was that SetCursorTwipPosition() assumed that there is
a selection already -- fix that by  adding the missing Stt/EndSelect()
calls and limiting the lifetime of the SwMvContext instance.

Change-Id: Iaeeadd8e4d9030614ee069b9fcfa269ce74ed58a

sw/qa/extras/tiledrendering/tiledrendering.cxx

@@ -163,6 +163,11 @@ void SwTiledRenderingTest::testSetTextSelection()
     pXTextDocument->setTextSelection(LOK_SETTEXTSELECTION_START, aStart.getX(), aStart.getY());
     // The new selection must include the first word, too -- but not the ending dot.
     CPPUNIT_ASSERT_EQUAL(OUString("Aaa bbb"), pShellCrsr->GetTxt());
+
+    // Next: test that LOK_SETTEXTSELECTION_RESET + LOK_SETTEXTSELECTION_END can be used to create a selection.
+    pXTextDocument->setTextSelection(LOK_SETTEXTSELECTION_RESET, aStart.getX(), aStart.getY());
+    pXTextDocument->setTextSelection(LOK_SETTEXTSELECTION_END, aStart.getX() + 1000, aStart.getY());
+    CPPUNIT_ASSERT_EQUAL(OUString("Aaa b"), pShellCrsr->GetTxt());
 }
 
 void SwTiledRenderingTest::testSetGraphicSelection()

sw/source/uibase/docvw/edtwin.cxx

@@ -6247,16 +6247,29 @@ void SwEditWin::SetCursorTwipPosition(const Point& rPosition, bool bPoint, bool
 
     // Not an SwWrtShell, as that would make SwCrsrShell::GetCrsr() inaccessible.
     SwEditShell& rShell = m_rView.GetWrtShell();
-    SwMvContext aMvContext(&rShell);
-    if (bClearMark)
-        rShell.ClearMark();
-    // If the mark is to be updated, then exchange the point and mark before
-    // and after, as we can't easily set the mark.
-    if (!bPoint)
-        rShell.getShellCrsr(/*bBlock=*/false)->Exchange();
-    rShell.SetCrsr(rPosition);
-    if (!bPoint)
-        rShell.getShellCrsr(/*bBlock=*/false)->Exchange();
+
+    bool bCreateSelection = false;
+    {
+        SwMvContext aMvContext(&rShell);
+        if (bClearMark)
+            rShell.ClearMark();
+        else
+            bCreateSelection = !rShell.HasMark();
+
+        if (bCreateSelection)
+            m_rView.GetWrtShell().SttSelect();
+
+        // If the mark is to be updated, then exchange the point and mark before
+        // and after, as we can't easily set the mark.
+        if (!bPoint)
+            rShell.getShellCrsr(/*bBlock=*/false)->Exchange();
+        rShell.SetCrsr(rPosition);
+        if (!bPoint)
+            rShell.getShellCrsr(/*bBlock=*/false)->Exchange();
+    }
+
+    if (bCreateSelection)
+        m_rView.GetWrtShell().EndSelect();
 }
 
 void SwEditWin::SetGraphicTwipPosition(bool bStart, const Point& rPosition)