[pdfmod] [PdfSharp] Handle Outlines' iref pointing to null

[Gabriel Burt <gburt src gnome org>]

commit 973c365b7a9f3e5b58feedc51fb02a07413453e8
Author: Gabriel Burt <gabriel burt gmail com>
Date:   Thu Mar 3 09:35:37 2011 -0600

    [PdfSharp] Handle Outlines' iref pointing to null
    
    If it does, remove it and recreate it.  Fixes a bug in PDF Mod where
    some documents would fail to load b/c the Outlines' iref pointed to null
    (bgo#642379).

 lib/PdfSharp/PdfSharp.Pdf.Advanced/PdfCatalog.cs |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/lib/PdfSharp/PdfSharp.Pdf.Advanced/PdfCatalog.cs b/lib/PdfSharp/PdfSharp.Pdf.Advanced/PdfCatalog.cs
index b995798..f785f00 100644
--- a/lib/PdfSharp/PdfSharp.Pdf.Advanced/PdfCatalog.cs
+++ b/lib/PdfSharp/PdfSharp.Pdf.Advanced/PdfCatalog.cs
@@ -145,8 +145,14 @@ namespace PdfSharp.Pdf.Advanced
     {
       get
       {
-        if (this.outline == null)
-          this.outline = (PdfOutline)Elements.GetValue(Keys.Outlines, VCF.CreateIndirect);
+        if (this.outline == null) {
+          try {
+            this.outline = (PdfOutline)Elements.GetValue(Keys.Outlines, VCF.CreateIndirect);
+          } catch (InvalidOperationException) {
+            Elements.Remove (Keys.Outlines);
+            this.outline = (PdfOutline)Elements.GetValue(Keys.Outlines, VCF.CreateIndirect);
+          }
+        }
         return this.outline.Outlines;
       }
     }