Check whether an outline contain required fields and throw an exception if not

For more information check out PDF Reference 8.2.2 Tables 8.3 and 8.4.

DEVSIX-3633

Author: ars18wrw

kernel/src/main/java/com/itextpdf/kernel/PdfException.java

@@ -330,6 +330,11 @@ public class PdfException extends RuntimeException {
     public static final String YouNeedASingleBooleanForThisCollectionSortDictionary = "You need a single boolean for this collection sort dictionary.";
     public static final String QuadPointArrayLengthIsNotAMultipleOfEight = "The QuadPoint Array length is not a multiple of 8.";
 
+    public static final String CORRUPTED_OUTLINE_NO_PARENT_ENTRY =
+            "Document outline is corrupted: some outline (PDF object: \"{0}\") lacks the required parent entry.";
+    public static final String CORRUPTED_OUTLINE_NO_TITLE_ENTRY =
+            "Document outline is corrupted: some outline (PDF object: \"{0}\") lacks the required title entry.";
+
     /**
      * Object for more details
      */

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfCatalog.java

@@ -724,14 +724,12 @@ private void addOutlineToPage(PdfOutline outline, PdfDictionary item, Map<String
     /**
      * Constructs {@link PdfCatalog#outlines} iteratively
      */
-    private void constructOutlines(PdfDictionary outlineRoot, Map<String, PdfObject> names) {
+    void constructOutlines(PdfDictionary outlineRoot, Map<String, PdfObject> names) {
         if (outlineRoot == null) {
             return;
         }
         PdfDictionary first = outlineRoot.getAsDictionary(PdfName.First);
         PdfDictionary current = first;
-        PdfDictionary next;
-        PdfDictionary parent;
         HashMap<PdfDictionary, PdfOutline> parentOutlineMap = new HashMap<>();
 
         outlines = new PdfOutline(OutlineRoot, outlineRoot, getDocument());
@@ -740,20 +738,30 @@ private void constructOutlines(PdfDictionary outlineRoot, Map<String, PdfObject>
 
         while (current != null) {
             first = current.getAsDictionary(PdfName.First);
-            next = current.getAsDictionary(PdfName.Next);
-            parent = current.getAsDictionary(PdfName.Parent);
-
+            PdfDictionary next = current.getAsDictionary(PdfName.Next);
+            PdfDictionary parent = current.getAsDictionary(PdfName.Parent);
+            if (null == parent) {
+                throw new PdfException(
+                        MessageFormatUtil.format(
+                                PdfException.CORRUPTED_OUTLINE_NO_PARENT_ENTRY,
+                                current.indirectReference));
+            }
+            PdfString title = current.getAsString(PdfName.Title);
+            if (null == title) {
+                throw new PdfException(
+                        MessageFormatUtil.format(
+                                PdfException.CORRUPTED_OUTLINE_NO_TITLE_ENTRY,
+                                current.indirectReference));
+            }
             parentOutline = parentOutlineMap.get(parent);
-            PdfOutline currentOutline = new PdfOutline(current.getAsString(PdfName.Title).toUnicodeString(), current, parentOutline);
+            PdfOutline currentOutline = new PdfOutline(title.toUnicodeString(), current, parentOutline);
             addOutlineToPage(currentOutline, current, names);
             parentOutline.getAllChildren().add(currentOutline);
 
             if (first != null) {
                 parentOutlineMap.put(current, currentOutline);
             }
             current = getNextOutline(first, next, parent);
-
         }
     }
-
 }

kernel/src/test/java/com/itextpdf/kernel/pdf/PdfOutlineTest.java

@@ -43,6 +43,8 @@ This file is part of the iText (R) project.
 package com.itextpdf.kernel.pdf;
 
 import com.itextpdf.io.LogMessageConstant;
+import com.itextpdf.io.util.MessageFormatUtil;
+import com.itextpdf.kernel.PdfException;
 import com.itextpdf.kernel.pdf.navigation.PdfDestination;
 import com.itextpdf.kernel.pdf.navigation.PdfExplicitDestination;
 import com.itextpdf.kernel.pdf.navigation.PdfStringDestination;
@@ -52,6 +54,8 @@ This file is part of the iText (R) project.
 import com.itextpdf.test.annotations.LogMessages;
 import com.itextpdf.test.annotations.type.IntegrationTest;
 
+import java.io.ByteArrayOutputStream;
+import java.util.HashMap;
 import org.xml.sax.SAXException;
 import javax.xml.parsers.ParserConfigurationException;
 import java.io.FileOutputStream;
@@ -508,4 +512,56 @@ public void removePageInDocWithComplexOutlineTreeStructTest() throws IOException
 
         Assert.assertNull(new CompareTool().compareByContent(output, cmp, DESTINATION_FOLDER, "diff_"));
     }
+
+    @Test
+    public void constructOutlinesNoParentTest() throws IOException {
+        try (
+                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                PdfDocument pdfDocument = new PdfDocument(new PdfWriter(baos))) {
+            pdfDocument.addNewPage();
+
+            PdfDictionary first = new PdfDictionary();
+            first.makeIndirect(pdfDocument);
+
+            PdfDictionary outlineDictionary = new PdfDictionary();
+            outlineDictionary.put(PdfName.First, first);
+
+            Exception exception = Assert.assertThrows(
+                    PdfException.class,
+                    () -> pdfDocument.getCatalog().constructOutlines(outlineDictionary, new HashMap<String, PdfObject>())
+            );
+            Assert.assertEquals(
+                    MessageFormatUtil.format(PdfException.CORRUPTED_OUTLINE_NO_PARENT_ENTRY,
+                            first.indirectReference),
+                    exception.getMessage());
+        }
+    }
+
+    @Test
+    public void constructOutlinesNoTitleTest() throws IOException {
+        try (
+                ByteArrayOutputStream baos = new ByteArrayOutputStream();
+                PdfDocument pdfDocument = new PdfDocument(new PdfWriter(baos))) {
+            pdfDocument.addNewPage();
+
+            PdfDictionary first = new PdfDictionary();
+            first.makeIndirect(pdfDocument);
+
+            PdfDictionary outlineDictionary = new PdfDictionary();
+            outlineDictionary.makeIndirect(pdfDocument);
+
+            outlineDictionary.put(PdfName.First, first);
+            first.put(PdfName.Parent, outlineDictionary);
+
+            Exception exception = Assert.assertThrows(
+                    PdfException.class,
+                    () -> pdfDocument.getCatalog()
+                            .constructOutlines(outlineDictionary, new HashMap<String, PdfObject>())
+            );
+            Assert.assertEquals(
+                    MessageFormatUtil.format(PdfException.CORRUPTED_OUTLINE_NO_TITLE_ENTRY,
+                            first.indirectReference),
+                    exception.getMessage());
+        }
+    }
 }