Construct PdfOutline iteratively

Prevents stackoverflow from occuring for documents with a large amount of bookmarks.
DEVSIX-1707

Autoported commit.
Original commit hash: [8c986f14e]

Author: JonPReilly

itext.tests/itext.kernel.tests/itext/kernel/pdf/PdfOutlineTest.cs

@@ -374,5 +374,18 @@ public virtual void AddOutlinesWithNamedDestinations02() {
             NUnit.Framework.Assert.IsNull(new CompareTool().CompareByContent(filename, sourceFolder + "cmp_outlinesWithNamedDestinations02.pdf"
                 , destinationFolder, "diff_"));
         }
+
+        /// <exception cref="System.IO.IOException"/>
+        [NUnit.Framework.Test]
+        public virtual void OutlineStackOverflowTest01() {
+            PdfReader reader = new PdfReader(sourceFolder + "outlineStackOverflowTest01.pdf");
+            PdfDocument pdfDoc = new PdfDocument(reader);
+            try {
+                pdfDoc.GetOutlines(true);
+            }
+            catch (StackOverflowException) {
+                NUnit.Framework.Assert.Fail("StackOverflow thrown when reading document with a large number of outlines.");
+            }
+        }
     }
 }

itext.tests/itext.kernel.tests/resources/itext/kernel/pdf/PdfOutlineTest/outlineStackOverflowTest01.pdf

@@ -24,6 +24,13 @@
                               "75bcdbcecb7caf1f0f4b6e7d013906ba60b66eb1c8298e4efb052caf6cece4bf1816" +
                               "902cc")]
 
+[assembly: InternalsVisibleTo("itext.layout,PublicKey=0024000004800000940000000602000000240000525" +
+                              "3413100040000010001008b21ed5b3fc1c11996390981fe22bbe71a39a9e11d3c2ce" +
+                              "fddd6ee92920fa871f9666ae0fa941af0280d0653df048ae2d93f8c5e2d820dba3c8" +
+                              "df9ed468c8be40a6fffeb32aa481a254f0fb9f37aa7c3ec1c0acd2c009746bbdafcb" +
+                              "75bcdbcecb7caf1f0f4b6e7d013906ba60b66eb1c8298e4efb052caf6cece4bf1816" +
+                              "902cc")]
+
 [assembly: ComVisible(false)]
 
 [assembly: Guid("39631ecb-1d39-4eb2-b775-37bd34cbf5a4")]

itext/itext.io/Properties/AssemblyInfo.cs

@@ -394,8 +394,7 @@ internal virtual PdfOutline GetOutlines(bool updateOutlines) {
                 outlines = new PdfOutline(GetDocument());
             }
             else {
-                outlines = new PdfOutline(OutlineRoot, outlineRoot, GetDocument());
-                GetNextItem(outlineRoot.GetAsDictionary(PdfName.First), outlines, destsTree.GetNames());
+                ConstructOutlines(outlineRoot, destsTree.GetNames());
             }
             return outlines;
         }
@@ -519,11 +518,70 @@ private void AddOutlineToPage(PdfOutline outline, IDictionary<String, PdfObject>
             }
         }
 
-        private void GetNextItem(PdfDictionary item, PdfOutline parent, IDictionary<String, PdfObject> names) {
-            if (null == item) {
-                return;
+        /// <summary>Get the next outline of the current node in the outline tree by looking for a child or sibling node.
+        ///     </summary>
+        /// <remarks>
+        /// Get the next outline of the current node in the outline tree by looking for a child or sibling node.
+        /// If there is no child or sibling of the current node
+        /// <see cref="GetParentNextOutline(PdfDictionary)"/>
+        /// is called to get a hierarchical parent's next node.
+        /// <see langword="null"/>
+        /// is returned if one does not exist.
+        /// </remarks>
+        /// <returns>
+        /// the
+        /// <see cref="PdfDictionary"/>
+        /// object of the next outline if one exists,
+        /// <see langword="null"/>
+        /// otherwise.
+        /// </returns>
+        private PdfDictionary GetNextOutline(PdfDictionary first, PdfDictionary next, PdfDictionary parent) {
+            if (first != null) {
+                return first;
+            }
+            else {
+                if (next != null) {
+                    return next;
+                }
+                else {
+                    return GetParentNextOutline(parent);
+                }
+            }
+        }
+
+        /// <summary>Gets the parent's next outline of the current node.</summary>
+        /// <remarks>
+        /// Gets the parent's next outline of the current node.
+        /// If the parent does not have a next we look at the grand parent, great-grand parent, etc until we find a next node or reach the root at which point
+        /// <see langword="null"/>
+        /// is returned to signify there is no next node present.
+        /// </remarks>
+        /// <returns>
+        /// the
+        /// <see cref="PdfDictionary"/>
+        /// object of the next outline if one exists,
+        /// <see langword="null"/>
+        /// otherwise.
+        /// </returns>
+        private PdfDictionary GetParentNextOutline(PdfDictionary parent) {
+            if (parent == null) {
+                return null;
             }
-            PdfOutline outline = new PdfOutline(item.GetAsString(PdfName.Title).ToUnicodeString(), item, parent);
+            PdfDictionary current = null;
+            while (current == null) {
+                current = parent.GetAsDictionary(PdfName.Next);
+                if (current == null) {
+                    parent = parent.GetAsDictionary(PdfName.Parent);
+                    if (parent == null) {
+                        return null;
+                    }
+                }
+            }
+            return current;
+        }
+
+        private void AddOutlineToPage(PdfOutline outline, PdfDictionary item, IDictionary<String, PdfObject> names
+            ) {
             PdfObject dest = item.Get(PdfName.Dest);
             if (dest != null) {
                 PdfDestination destination = PdfDestination.MakeDestination(dest);
@@ -535,7 +593,7 @@ private void GetNextItem(PdfDictionary item, PdfOutline parent, IDictionary<Stri
                 PdfDictionary action = item.GetAsDictionary(PdfName.A);
                 if (action != null) {
                     PdfName actionType = action.GetAsName(PdfName.S);
-                    //Check if it a go to action
+                    //Check if it is a go to action
                     if (PdfName.GoTo.Equals(actionType)) {
                         //Retrieve destination if it is.
                         PdfObject destObject = action.Get(PdfName.D);
@@ -548,14 +606,43 @@ private void GetNextItem(PdfDictionary item, PdfOutline parent, IDictionary<Stri
                     }
                 }
             }
-            parent.GetAllChildren().Add(outline);
-            PdfDictionary processItem = item.GetAsDictionary(PdfName.First);
-            if (processItem != null) {
-                GetNextItem(processItem, outline, names);
+        }
+
+        /// <summary>
+        /// Constructs
+        /// <see cref="outlines"/>
+        /// iteratively
+        /// </summary>
+        private void ConstructOutlines(PdfDictionary outlineRoot, IDictionary<String, PdfObject> names) {
+            if (outlineRoot == null) {
+                return;
             }
-            processItem = item.GetAsDictionary(PdfName.Next);
-            if (processItem != null) {
-                GetNextItem(processItem, parent, names);
+            PdfDictionary first = outlineRoot.GetAsDictionary(PdfName.First);
+            PdfDictionary current = first;
+            PdfDictionary next;
+            PdfDictionary parent;
+            Dictionary<PdfDictionary, PdfOutline> parentOutlineMap = new Dictionary<PdfDictionary, PdfOutline>();
+            outlines = new PdfOutline(OutlineRoot, outlineRoot, GetDocument());
+            PdfOutline parentOutline = outlines;
+            parentOutlineMap.Put(outlineRoot, parentOutline);
+            while (current != null) {
+                first = current.GetAsDictionary(PdfName.First);
+                next = current.GetAsDictionary(PdfName.Next);
+                parent = current.GetAsDictionary(PdfName.Parent);
+                parentOutline = parentOutlineMap.Get(parent);
+                PdfOutline currentOutline = new PdfOutline(current.GetAsString(PdfName.Title).ToUnicodeString(), current, 
+                    parentOutline);
+                AddOutlineToPage(currentOutline, current, names);
+                parentOutline.GetAllChildren().Add(currentOutline);
+                if (first != null) {
+                    parentOutlineMap.Put(current, currentOutline);
+                }
+                else {
+                    if (current == parent.GetAsDictionary(PdfName.Last)) {
+                        parentOutlineMap.JRemove(parent);
+                    }
+                }
+                current = GetNextOutline(first, next, parent);
             }
         }
     }

itext/itext.kernel/itext/kernel/pdf/PdfCatalog.cs

@@ -48,6 +48,7 @@ source product.
 using System.Linq;
 using System.Reflection;
 using System.Text;
+using iText.IO.Util.Collections;
 
 namespace iText.Layout {
     internal static class LayoutExtensions {
@@ -216,7 +217,7 @@ public static Attribute GetCustomAttribute(this Assembly assembly, Type attribut
 
 #if NETSTANDARD1_6
         public static MethodInfo GetMethod(this Type type, String methodName, Type[] parameterTypes) {
-            return type.GetTypeInfo().GetMethod(methodName, parameterTypes);
+            return type    .GetTypeInfo().GetMethod(methodName, parameterTypes);
         }
 
         public static ConstructorInfo GetConstructor(this Type type, Type[] parameterTypes) {

itext/itext.layout/itext/layout/LayoutExtensions.cs

@@ -1 +1 @@
-4e4cfb45170aab18c72236302590b5533d50f69d
+8c986f14e6ff65251affa952cb41d17ba245ad6c