Allow XPdfForm to open password protected PDFs

Author: DilanBoskan

PdfSharpCore/Drawing/XPdfForm.cs

@@ -93,6 +93,21 @@ internal XPdfForm(Stream stream)
             _externalDocument = PdfReader.Open(stream);
         }
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="XPdfForm"/> class from a stream and password.
+        /// </summary>
+        /// <param name="stream">The stream.</param>
+        /// <param name="password">The password.</param>
+        internal XPdfForm(Stream stream, string password) {
+            // Create a dummy unique path
+            _path = "*" + Guid.NewGuid().ToString("B");
+
+            if (PdfReader.TestPdfFile(stream) == 0)
+                throw new ArgumentException("The specified stream has no valid PDF file header.", "stream");
+
+            _externalDocument = PdfReader.Open(stream, password, PdfDocumentOpenMode.ReadOnly);
+        }
+
         /// <summary>
         /// Creates an XPdfForm from a file.
         /// </summary>
@@ -110,6 +125,13 @@ public static XPdfForm FromStream(Stream stream)
             return new XPdfForm(stream);
         }
 
+        /// <summary>
+        /// Creates an XPdfForm from a stream and a password.
+        /// </summary>
+        public static XPdfForm FromStream(Stream stream, string password) {
+            return new XPdfForm(stream, password);
+        }
+
         /*
             void Initialize()
             {