MimeMessage and MimeEntity now implement IDisposable

Fixes issue #732

MimeKit/AttachmentCollection.cs

@@ -102,10 +102,11 @@ public bool IsReadOnly {
 		}
 
 		/// <summary>
-		/// Gets or sets the <see cref="MimeEntity"/> at the specified index.
+		/// Get or set the <see cref="MimeEntity"/> at the specified index.
 		/// </summary>
 		/// <remarks>
-		/// Gets or sets the <see cref="MimeEntity"/> at the specified index.
+		/// <para>Gets or sets the <see cref="MimeEntity"/> at the specified index.</para>
+		/// <note type="note">It is the responsibility of the caller to dispose the original entity at the specified <paramref name="index"/>.</note>
 		/// </remarks>
 		/// <value>The attachment at the specified index.</value>
 		/// <param name="index">The index.</param>
@@ -796,6 +797,23 @@ public void Add (MimeEntity attachment)
 		/// </remarks>
 		public void Clear ()
 		{
+			Clear (false);
+		}
+
+		/// <summary>
+		/// Clears the attachment collection.
+		/// </summary>
+		/// <remarks>
+		/// Removes all attachments from the collection, optionally disposing them in the process.
+		/// </remarks>
+		/// <param name="dispose"><c>true</c> if all of the attachments should be disposed; otherwise, <c>false</c>.</param>
+		public void Clear (bool dispose)
+		{
+			if (dispose) {
+				for (int i = 0; i < attachments.Count; i++)
+					attachments[i].Dispose ();
+			}
+
 			attachments.Clear ();
 		}
 
@@ -912,7 +930,8 @@ public bool Remove (MimeEntity attachment)
 		/// Removes the attachment at the specified index.
 		/// </summary>
 		/// <remarks>
-		/// Removes the attachment at the specified index.
+		/// <para>Removes the attachment at the specified index.</para>
+		/// <note type="note">It is the responsibility of the caller to dispose the entity at the specified <paramref name="index"/>.</note>
 		/// </remarks>
 		/// <param name="index">The index.</param>
 		/// <exception cref="System.ArgumentOutOfRangeException">

MimeKit/Cryptography/ApplicationPgpEncrypted.cs

@@ -71,6 +71,11 @@ public ApplicationPgpEncrypted () : base ("application", "pgp-encrypted")
 			Content = new MimeContent (content);
 		}
 
+		void CheckDisposed ()
+		{
+			CheckDisposed (nameof (ApplicationPgpEncrypted));
+		}
+
 		/// <summary>
 		/// Dispatches to the specific visit method for this MIME entity.
 		/// </summary>
@@ -86,11 +91,16 @@ public ApplicationPgpEncrypted () : base ("application", "pgp-encrypted")
 		/// <exception cref="System.ArgumentNullException">
 		/// <paramref name="visitor"/> is <c>null</c>.
 		/// </exception>
+		/// <exception cref="System.ObjectDisposedException">
+		/// The <see cref="ApplicationPgpEncrypted"/> has been disposed.
+		/// </exception>
 		public override void Accept (MimeVisitor visitor)
 		{
 			if (visitor == null)
 				throw new ArgumentNullException (nameof (visitor));
 
+			CheckDisposed ();
+
 			visitor.VisitApplicationPgpEncrypted (this);
 		}
 	}

MimeKit/Cryptography/ApplicationPgpSignature.cs

@@ -80,6 +80,11 @@ public ApplicationPgpSignature (Stream stream) : base ("application", "pgp-signa
 			FileName = "signature.asc";
 		}
 
+		void CheckDisposed ()
+		{
+			CheckDisposed (nameof (ApplicationPgpSignature));
+		}
+
 		/// <summary>
 		/// Dispatches to the specific visit method for this MIME entity.
 		/// </summary>
@@ -95,11 +100,16 @@ public ApplicationPgpSignature (Stream stream) : base ("application", "pgp-signa
 		/// <exception cref="System.ArgumentNullException">
 		/// <paramref name="visitor"/> is <c>null</c>.
 		/// </exception>
+		/// <exception cref="System.ObjectDisposedException">
+		/// The <see cref="ApplicationPgpSignature"/> has been disposed.
+		/// </exception>
 		public override void Accept (MimeVisitor visitor)
 		{
 			if (visitor == null)
 				throw new ArgumentNullException (nameof (visitor));
 
+			CheckDisposed ();
+
 			visitor.VisitApplicationPgpSignature (this);
 		}
 	}