Fix several issues with PdfOutline processing

- support processing of incorrect hierarchy of outlines when merging
- process PdfNumber as page argument for outline destinations
- support copying of named destinations

DEVSIX-2517

Autoported commit.
Original commit hash: [0e5b707dd]

Author: LodrKumquat

itext.tests/itext.kernel.tests/itext/kernel/pdf/PdfDestinationTest.cs

@@ -168,6 +168,38 @@ public virtual void DestCopyingTest05() {
                 ));
         }
 
+        /// <exception cref="System.IO.IOException"/>
+        /// <exception cref="System.Exception"/>
+        [NUnit.Framework.Test]
+        public virtual void DestCopyingTest06() {
+            String srcFile = sourceFolder + "sourceWithNamedDestination.pdf";
+            String outFile = destinationFolder + "destCopyingTest06.pdf";
+            String cmpFile = sourceFolder + "cmp_destCopyingTest06.pdf";
+            PdfDocument srcDoc = new PdfDocument(new PdfReader(srcFile));
+            PdfDocument destDoc = new PdfDocument(new PdfWriter(outFile));
+            srcDoc.CopyPagesTo(JavaUtil.ArraysAsList(1, 2, 1), destDoc);
+            destDoc.Close();
+            srcDoc.Close();
+            NUnit.Framework.Assert.IsNull(new CompareTool().CompareByContent(outFile, cmpFile, destinationFolder, "diff_"
+                ));
+        }
+
+        /// <exception cref="System.IO.IOException"/>
+        /// <exception cref="System.Exception"/>
+        [NUnit.Framework.Test]
+        public virtual void DestCopyingTest07() {
+            String srcFile = sourceFolder + "sourceStringDestWithPageNumber.pdf";
+            String outFile = destinationFolder + "destCopyingTest07.pdf";
+            String cmpFile = sourceFolder + "cmp_destCopyingTest07.pdf";
+            PdfDocument srcDoc = new PdfDocument(new PdfReader(srcFile));
+            PdfDocument destDoc = new PdfDocument(new PdfWriter(outFile));
+            srcDoc.CopyPagesTo(JavaUtil.ArraysAsList(1, 2, 1), destDoc);
+            destDoc.Close();
+            srcDoc.Close();
+            NUnit.Framework.Assert.IsNull(new CompareTool().CompareByContent(outFile, cmpFile, destinationFolder, "diff_"
+                ));
+        }
+
         /// <exception cref="System.IO.IOException"/>
         /// <exception cref="System.Exception"/>
         [NUnit.Framework.Test]

itext.tests/itext.kernel.tests/itext/kernel/utils/PdfMergerTest.cs

@@ -242,5 +242,30 @@ public virtual void MergeTableWithEmptyTdTest() {
                 NUnit.Framework.Assert.Fail(errorMessage);
             }
         }
+
+        /// <exception cref="System.IO.IOException"/>
+        /// <exception cref="System.Exception"/>
+        [NUnit.Framework.Test]
+        [LogMessage(iText.IO.LogMessageConstant.NAME_ALREADY_EXISTS_IN_THE_NAME_TREE, Count = 2)]
+        public virtual void MergeOutlinesNamedDestinations() {
+            String filename = sourceFolder + "outlinesNamedDestinations.pdf";
+            String resultFile = destinationFolder + "mergeOutlinesNamedDestinations.pdf";
+            PdfReader reader = new PdfReader(filename);
+            PdfDocument sourceDoc = new PdfDocument(reader);
+            PdfDocument output = new PdfDocument(new PdfWriter(resultFile));
+            PdfMerger merger = new PdfMerger(output).SetCloseSourceDocuments(false);
+            merger.Merge(sourceDoc, 2, 3);
+            merger.Merge(sourceDoc, 2, 3);
+            sourceDoc.Close();
+            reader.Close();
+            merger.Close();
+            output.Close();
+            CompareTool compareTool = new CompareTool();
+            String errorMessage = compareTool.CompareByContent(resultFile, sourceFolder + "cmp_mergeOutlinesNamedDestinations.pdf"
+                , destinationFolder, "diff_");
+            if (errorMessage != null) {
+                NUnit.Framework.Assert.Fail(errorMessage);
+            }
+        }
     }
 }

itext.tests/itext.kernel.tests/resources/itext/kernel/pdf/PdfDestinationTest/cmp_destCopyingTest06.pdf

@@ -464,19 +464,26 @@ internal virtual PdfDestination CopyDestination(PdfObject dest, IDictionary<PdfP
                 }
             }
             else {
-                if (dest.IsString()) {
+                if (dest.IsString() || dest.IsName()) {
                     PdfNameTree destsTree = GetNameTree(PdfName.Dests);
                     IDictionary<String, PdfObject> dests = destsTree.GetNames();
-                    String srcDestName = ((PdfString)dest).ToUnicodeString();
+                    String srcDestName = dest.IsString() ? ((PdfString)dest).ToUnicodeString() : ((PdfName)dest).GetValue();
                     PdfArray srcDestArray = (PdfArray)dests.Get(srcDestName);
                     if (srcDestArray != null) {
                         PdfObject pageObject = srcDestArray.Get(0);
+                        if (pageObject is PdfNumber) {
+                            pageObject = GetDocument().GetPage(((PdfNumber)pageObject).IntValue() + 1).GetPdfObject();
+                        }
                         foreach (PdfPage oldPage in page2page.Keys) {
                             if (oldPage.GetPdfObject() == pageObject) {
                                 d = new PdfStringDestination(srcDestName);
                                 if (!IsEqualSameNameDestExist(page2page, toDocument, srcDestName, srcDestArray, oldPage)) {
                                     // in the copiedArray old page ref will be correctly replaced by the new page ref as this page is already copied
                                     PdfArray copiedArray = (PdfArray)srcDestArray.CopyTo(toDocument, false);
+                                    // here we can safely replace first item of the array because array of NamedDestination or StringDestination
+                                    // never refers to page in another document via PdfNumber, but should always refer to page within current document
+                                    // via page object reference.
+                                    copiedArray.Set(0, page2page.Get(oldPage).GetPdfObject());
                                     toDocument.AddNamedDestination(srcDestName, copiedArray);
                                 }
                                 break;
@@ -508,6 +515,9 @@ private bool IsEqualSameNameDestExist(IDictionary<PdfPage, PdfPage> page2page, P
 
         private void AddOutlineToPage(PdfOutline outline, IDictionary<String, PdfObject> names) {
             PdfObject pageObj = outline.GetDestination().GetDestinationPage(names);
+            if (pageObj is PdfNumber) {
+                pageObj = GetDocument().GetPage(((PdfNumber)pageObj).IntValue() + 1).GetPdfObject();
+            }
             if (pageObj != null) {
                 IList<PdfOutline> outs = pagesWithOutlines.Get(pageObj);
                 if (outs == null) {
@@ -637,11 +647,6 @@ private void ConstructOutlines(PdfDictionary outlineRoot, IDictionary<String, Pd
                 if (first != null) {
                     parentOutlineMap.Put(current, currentOutline);
                 }
-                else {
-                    if (current == parent.GetAsDictionary(PdfName.Last)) {
-                        parentOutlineMap.JRemove(parent);
-                    }
-                }
                 current = GetNextOutline(first, next, parent);
             }
         }

itext.tests/itext.kernel.tests/resources/itext/kernel/pdf/PdfDestinationTest/cmp_destCopyingTest07.pdf

@@ -1105,9 +1105,7 @@ public virtual IList<PdfPage> CopyPagesTo(IList<int> pagesToCopy, iText.Kernel.P
                 PdfPage page = GetPage((int)pageNum);
                 PdfPage newPage = page.CopyTo(toDocument, copier);
                 copiedPages.Add(newPage);
-                if (!page2page.ContainsKey(page)) {
-                    page2page.Put(page, newPage);
-                }
+                page2page.Put(page, newPage);
                 if (lastCopiedPageNum >= pageNum) {
                     rangesOfPagesWithIncreasingNumbers.Add(new Dictionary<PdfPage, PdfPage>());
                 }