[dotnet] Add nullability annotations to print types (#14773)

Author: RenderMichael

dotnet/src/webdriver/EncodedFile.cs

@@ -19,41 +19,41 @@
 
 using System;
 
+#nullable enable
+
 namespace OpenQA.Selenium
 {
     /// <summary>
     /// Represents a file transmitted over the wire as a base64-encoded string.
     /// </summary>
     public abstract class EncodedFile
     {
-        private string base64Encoded = string.Empty;
-        private byte[] byteArray;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="EncodedFile"/> class.
         /// </summary>
         /// <param name="base64EncodedFile">The file as a Base64-encoded string.</param>
+        /// <exception cref="ArgumentNullException">If <paramref name="base64EncodedFile"/> is <see langword="null"/>.</exception>
+        /// <exception cref="FormatException">
+        /// <para>The length of <paramref name="base64EncodedFile"/>, ignoring white-space characters, is not zero or a multiple of 4.</para>
+        /// <para>-or-</para>
+        /// <para>The format of <paramref name="base64EncodedFile"/> is invalid. <paramref name="base64EncodedFile"/> contains a non-base-64 character,
+        /// more than two padding characters, or a non-white space-character among the padding characters.</para>
+        /// </exception>
         protected EncodedFile(string base64EncodedFile)
         {
-            this.base64Encoded = base64EncodedFile;
-            this.byteArray = Convert.FromBase64String(this.base64Encoded);
+            this.AsBase64EncodedString = base64EncodedFile ?? throw new ArgumentNullException(nameof(base64EncodedFile));
+            this.AsByteArray = Convert.FromBase64String(base64EncodedFile);
         }
 
         /// <summary>
         /// Gets the value of the encoded file as a Base64-encoded string.
         /// </summary>
-        public string AsBase64EncodedString
-        {
-            get { return this.base64Encoded; }
-        }
+        public string AsBase64EncodedString { get; }
 
         /// <summary>
         /// Gets the value of the encoded file as an array of bytes.
         /// </summary>
-        public byte[] AsByteArray
-        {
-            get { return this.byteArray; }
-        }
+        public byte[] AsByteArray { get; }
 
         /// <summary>
         /// Saves the file, overwriting it if it already exists.
@@ -65,9 +65,6 @@ public byte[] AsByteArray
         /// Returns a <see cref="string">String</see> that represents the current <see cref="object">Object</see>.
         /// </summary>
         /// <returns>A <see cref="string">String</see> that represents the current <see cref="object">Object</see>.</returns>
-        public override string ToString()
-        {
-            return this.base64Encoded;
-        }
+        public override string ToString() => this.AsBase64EncodedString;
     }
 }

dotnet/src/webdriver/ISupportsPrint.cs

@@ -17,6 +17,10 @@
 // under the License.
 // </copyright>
 
+using System;
+
+#nullable enable
+
 namespace OpenQA.Selenium
 {
     /// <summary>
@@ -29,6 +33,7 @@ public interface ISupportsPrint
         /// </summary>
         /// <param name="options">A <see cref="PrintOptions"/> object describing the options of the printed document.</param>
         /// <returns>The <see cref="PrintDocument"/> object containing the PDF-formatted print representation of the page.</returns>
+        /// <exception cref="ArgumentNullException">If <paramref name="options"/> is <see langword="null"/>.</exception>
         PrintDocument Print(PrintOptions options);
     }
 }

dotnet/src/webdriver/PrintDocument.cs

@@ -20,6 +20,8 @@
 using System;
 using System.IO;
 
+#nullable enable
+
 namespace OpenQA.Selenium
 {
     /// <summary>
@@ -31,6 +33,13 @@ public class PrintDocument : EncodedFile
         /// Initializes a new instance of the <see cref="PrintDocument"/> class.
         /// </summary>
         /// <param name="base64EncodedDocument">The printed document as a Base64-encoded string.</param>
+        /// <exception cref="ArgumentNullException">If <paramref name="base64EncodedDocument"/> is <see langword="null"/>.</exception>
+        /// <exception cref="FormatException">
+        /// <para>The length of <paramref name="base64EncodedDocument"/>, ignoring white-space characters, is not zero or a multiple of 4.</para>
+        /// <para>-or-</para>
+        /// <para>The format of <paramref name="base64EncodedDocument"/> is invalid. <paramref name="base64EncodedDocument"/> contains a non-base-64 character,
+        /// more than two padding characters, or a non-white space-character among the padding characters.</para>
+        /// </exception>
         public PrintDocument(string base64EncodedDocument) : base(base64EncodedDocument)
         {
         }
@@ -39,6 +48,14 @@ public PrintDocument(string base64EncodedDocument) : base(base64EncodedDocument)
         /// Saves this <see cref="PrintDocument"/> as a PDF formatted file, overwriting the file if it already exists.
         /// </summary>
         /// <param name="fileName">The full path and file name to save the printed document to.</param>
+        /// <exception cref="ArgumentException">
+        /// <para>If <paramref name="fileName"/> is <see langword="null"/> or whitespace.</para>
+        /// <para>-or-</para>
+        /// <para><paramref name="fileName"/> refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in an NTFS environment.</para>
+        /// </exception>
+        /// <exception cref="NotSupportedException"><paramref name="fileName"/> refers to a non-file device, such as "con:", "com1:", "lpt1:", etc. in a non-NTFS environment.</exception>
+        /// <exception cref="DirectoryNotFoundException">The specified path is invalid, such as being on an unmapped drive.</exception>
+        /// <exception cref="PathTooLongException">The specified path, file name, or both exceed the system-defined maximum length.</exception>
         public override void SaveAsFile(string fileName)
         {
             if (string.IsNullOrEmpty(fileName))