Fix constructor of PdfReader to close() the PdfTokenizer when exception thrown

Add PdfWriter/PdfReader/PdfDocument constructors to try-with-resources
Add tests to compareLinkAnnotation method and encrypt method

DEVSIX-3504

Autoported commit.
Original commit hash: [0178a9fec]

Author: Yahor Martsynkovsky

itext.tests/itext.kernel.tests/itext/kernel/pdf/PdfEncryptorTest.cs

@@ -0,0 +1,81 @@
+/*
+This file is part of the iText (R) project.
+Copyright (c) 1998-2021 iText Group NV
+Authors: iText Software.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License version 3
+as published by the Free Software Foundation with the addition of the
+following permission added to Section 15 as permitted in Section 7(a):
+FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
+ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
+OF THIRD PARTY RIGHTS
+
+This program is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.
+See the GNU Affero General Public License for more details.
+You should have received a copy of the GNU Affero General Public License
+along with this program; if not, see http://www.gnu.org/licenses or write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA, 02110-1301 USA, or download the license from the following URL:
+http://itextpdf.com/terms-of-use/
+
+The interactive user interfaces in modified source and object code versions
+of this program must display Appropriate Legal Notices, as required under
+Section 5 of the GNU Affero General Public License.
+
+In accordance with Section 7(b) of the GNU Affero General Public License,
+a covered work must retain the producer line in every PDF that is created
+or manipulated using iText.
+
+You can be released from the requirements of the license by purchasing
+a commercial license. Buying such a license is mandatory as soon as you
+develop commercial activities involving the iText software without
+disclosing the source code of your own applications.
+These activities include: offering paid services to customers as an ASP,
+serving PDFs on the fly in a web application, shipping iText with a closed
+source product.
+
+For more information, please contact iText Software Corp. at this
+address: [email protected]
+*/
+using System;
+using System.IO;
+using iText.Test;
+
+namespace iText.Kernel.Pdf {
+    public class PdfEncryptorTest : ExtendedITextTest {
+        public static readonly String SOURCE_FOLDER = iText.Test.TestUtil.GetParentProjectDirectory(NUnit.Framework.TestContext
+            .CurrentContext.TestDirectory) + "/resources/itext/kernel/pdf/PdfEncryptorTest/";
+
+        public static readonly String DESTINATION_FOLDER = NUnit.Framework.TestContext.CurrentContext.TestDirectory
+             + "/test/itext/kernel/pdf/PdfEncryptorTest/";
+
+        [NUnit.Framework.OneTimeSetUp]
+        public static void BeforeClass() {
+            CreateDestinationFolder(DESTINATION_FOLDER);
+        }
+
+        [NUnit.Framework.Test]
+        public virtual void EncryptFileTest() {
+            String outFileName = DESTINATION_FOLDER + "encryptFileTest.pdf";
+            String initialFileName = SOURCE_FOLDER + "initial.pdf";
+            PdfEncryptor encryptor = new PdfEncryptor();
+            EncryptionProperties encryptionProperties = new EncryptionProperties();
+            encryptionProperties.SetStandardEncryption(new byte[16], new byte[16], 0, 0);
+            encryptor.SetEncryptionProperties(encryptionProperties);
+            using (PdfReader initialFile = new PdfReader(initialFileName)) {
+                using (FileStream outputStream = new FileStream(outFileName, FileMode.Create)) {
+                    encryptor.Encrypt(initialFile, outputStream);
+                }
+            }
+            ReaderProperties readerProperties = new ReaderProperties();
+            readerProperties.SetPassword(new byte[16]);
+            PdfReader outFile = new PdfReader(outFileName, readerProperties);
+            PdfDocument doc = new PdfDocument(outFile);
+            doc.Close();
+            NUnit.Framework.Assert.IsTrue(outFile.IsEncrypted());
+        }
+    }
+}

itext.tests/itext.kernel.tests/itext/kernel/utils/CompareToolTest.cs

@@ -43,7 +43,14 @@ source product.
 using System;
 using System.IO;
 using iText.IO;
+using iText.IO.Font.Constants;
 using iText.IO.Util;
+using iText.Kernel.Font;
+using iText.Kernel.Geom;
+using iText.Kernel.Pdf;
+using iText.Kernel.Pdf.Annot;
+using iText.Kernel.Pdf.Canvas;
+using iText.Kernel.Pdf.Navigation;
 using iText.Test;
 using iText.Test.Attributes;
 
@@ -196,5 +203,61 @@ public virtual void CompareVisuallyDiffTestTest() {
             NUnit.Framework.Assert.IsTrue(new FileInfo(destinationFolder + "diff_1.png").Exists);
             NUnit.Framework.Assert.IsTrue(new FileInfo(destinationFolder + "diff_2.png").Exists);
         }
+
+        [NUnit.Framework.Test]
+        public virtual void CompareDiffFilesWithSameLinkAnnotationTest() {
+            String firstPdf = destinationFolder + "firstPdf.pdf";
+            String secondPdf = destinationFolder + "secondPdf.pdf";
+            PdfDocument firstDocument = new PdfDocument(new PdfWriter(firstPdf));
+            PdfPage page1FirstDocument = firstDocument.AddNewPage();
+            PdfCanvas canvas = new PdfCanvas(page1FirstDocument);
+            canvas.BeginText();
+            canvas.SetFontAndSize(PdfFontFactory.CreateFont(StandardFonts.COURIER_BOLD), 14);
+            canvas.MoveText(100, 600);
+            canvas.ShowText("Page 1");
+            canvas.MoveText(0, -30);
+            canvas.ShowText("Link to page 1. Click here!");
+            canvas.EndText();
+            canvas.Release();
+            page1FirstDocument.AddAnnotation(new PdfLinkAnnotation(new Rectangle(100, 560, 260, 25)).SetDestination(PdfExplicitDestination
+                .CreateFit(page1FirstDocument)).SetBorder(new PdfArray(new float[] { 0, 0, 1 })));
+            page1FirstDocument.Flush();
+            firstDocument.Close();
+            PdfDocument secondDocument = new PdfDocument(new PdfWriter(secondPdf));
+            PdfPage page1secondDocument = secondDocument.AddNewPage();
+            canvas = new PdfCanvas(page1secondDocument);
+            canvas.BeginText();
+            canvas.SetFontAndSize(PdfFontFactory.CreateFont(StandardFonts.COURIER_BOLD), 14);
+            canvas.MoveText(100, 600);
+            canvas.ShowText("Page 1 wit different Text");
+            canvas.MoveText(0, -30);
+            canvas.ShowText("Link to page 1. Click here!");
+            canvas.EndText();
+            canvas.Release();
+            page1secondDocument.AddAnnotation(new PdfLinkAnnotation(new Rectangle(100, 560, 260, 25)).SetDestination(PdfExplicitDestination
+                .CreateFit(page1secondDocument)).SetBorder(new PdfArray(new float[] { 0, 0, 1 })));
+            page1secondDocument.Flush();
+            secondDocument.Close();
+            NUnit.Framework.Assert.IsNull(new CompareTool().CompareLinkAnnotations(firstPdf, secondPdf));
+        }
+
+        [NUnit.Framework.Test]
+        public virtual void CompareFilesWithDiffLinkAnnotationTest() {
+            String firstPdf = destinationFolder + "outPdf.pdf";
+            String secondPdf = destinationFolder + "secondPdf.pdf";
+            PdfDocument firstDocument = new PdfDocument(new PdfWriter(firstPdf));
+            PdfDocument secondDocument = new PdfDocument(new PdfWriter(secondPdf));
+            PdfPage page1FirstDocument = firstDocument.AddNewPage();
+            page1FirstDocument.AddAnnotation(new PdfLinkAnnotation(new Rectangle(100, 560, 400, 50)).SetDestination(PdfExplicitDestination
+                .CreateFit(page1FirstDocument)).SetBorder(new PdfArray(new float[] { 0, 0, 1 })));
+            page1FirstDocument.Flush();
+            firstDocument.Close();
+            PdfPage page1SecondDocument = secondDocument.AddNewPage();
+            page1SecondDocument.AddAnnotation(new PdfLinkAnnotation(new Rectangle(100, 560, 260, 25)).SetDestination(PdfExplicitDestination
+                .CreateFit(page1SecondDocument)).SetBorder(new PdfArray(new float[] { 0, 0, 1 })));
+            page1SecondDocument.Flush();
+            secondDocument.Close();
+            NUnit.Framework.Assert.IsNotNull(new CompareTool().CompareLinkAnnotations(firstPdf, secondPdf));
+        }
     }
 }

itext.tests/itext.kernel.tests/resources/itext/kernel/pdf/PdfEncryptorTest/initial.pdf

@@ -234,14 +234,21 @@ public iText.Kernel.Pdf.PdfEncryptor SetEncryptionProperties(EncryptionPropertie
         public void Encrypt(PdfReader reader, Stream os, IDictionary<String, String> newInfo) {
             WriterProperties writerProperties = new WriterProperties();
             writerProperties.encryptionProperties = properties;
-            PdfWriter writer = new PdfWriter(os, writerProperties);
             StampingProperties stampingProperties = new StampingProperties();
             stampingProperties.SetEventCountingMetaInfo(metaInfo);
-            PdfDocument document = new PdfDocument(reader, writer, stampingProperties);
-            document.GetDocumentInfo().SetMoreInfo(newInfo);
-            document.Close();
+            try {
+                using (PdfWriter writer = new PdfWriter(os, writerProperties)) {
+                    using (PdfDocument document = new PdfDocument(reader, writer, stampingProperties)) {
+                        document.GetDocumentInfo().SetMoreInfo(newInfo);
+                    }
+                }
+            }
+            catch (System.IO.IOException) {
+            }
         }
 
+        //The close() method of OutputStream throws an exception, but we don't need to do anything in this case,
+        // because OutputStream#close() does nothing.
         /// <summary>Entry point to encrypt a PDF document.</summary>
         /// <param name="reader">the read PDF</param>
         /// <param name="os">the output destination</param>

itext/itext.kernel/itext/kernel/pdf/PdfEncryptor.cs

@@ -1444,8 +1444,21 @@ private void ReadDecryptObj() {
         /// <param name="byteSource">the source to check</param>
         /// <returns>a tokeniser that is guaranteed to start at the PDF header</returns>
         private static PdfTokenizer GetOffsetTokeniser(IRandomAccessSource byteSource) {
+            iText.IO.IOException possibleException = null;
             PdfTokenizer tok = new PdfTokenizer(new RandomAccessFileOrArray(byteSource));
-            int offset = tok.GetHeaderOffset();
+            int offset;
+            try {
+                offset = tok.GetHeaderOffset();
+            }
+            catch (iText.IO.IOException ex) {
+                possibleException = ex;
+                throw possibleException;
+            }
+            finally {
+                if (possibleException != null) {
+                    tok.Close();
+                }
+            }
             if (offset != 0) {
                 IRandomAccessSource offsetSource = new WindowRandomAccessSource(byteSource, offset);
                 tok = new PdfTokenizer(new RandomAccessFileOrArray(offsetSource));