expose Options property on descriptors

csharp/src/Google.Protobuf/Reflection/EnumDescriptor.cs

@@ -128,24 +128,14 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this enum.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value enum option for this descriptor
+        /// The <c>EnumOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<EnumOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value enum option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<EnumOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public EnumOptions Options => (Proto.Options as IDeepCloneable<EnumOptions>)?.Clone();
     }
 }

csharp/src/Google.Protobuf/Reflection/EnumValueDescriptor.cs

@@ -73,25 +73,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this enum value.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value enum value option for this descriptor
+        /// The <c>EnumValueOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<EnumValueOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value enum value option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<EnumValueOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public EnumValueOptions Options => (Proto.Options as IDeepCloneable<EnumValueOptions>)?.Clone();
     }
 }
  

csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs

@@ -304,25 +304,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this field.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value field option for this descriptor
+        /// The <c>FieldOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<FieldOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value field option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<FieldOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public FieldOptions Options => (Proto.Options as IDeepCloneable<FieldOptions>)?.Clone();
 
         /// <summary>
         /// Look up and cross-link all field types etc.

csharp/src/Google.Protobuf/Reflection/FileDescriptor.cs

@@ -547,25 +547,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this file.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value file option for this descriptor
+        /// The <c>FileOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<FileOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value file option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<FileOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public FileOptions Options => (Proto.Options as IDeepCloneable<FileOptions>)?.Clone();
 
         /// <summary>
         /// Performs initialization for the given generic type argument.

csharp/src/Google.Protobuf/Reflection/MessageDescriptor.cs

@@ -287,25 +287,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this message.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value message option for this descriptor
+        /// The <c>MessageOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<MessageOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value message option for this descriptor
-        /// </summary>
-        public Collections.RepeatedField<T> GetOption<T>(RepeatedExtension<MessageOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public MessageOptions Options => (Proto.Options as IDeepCloneable<MessageOptions>)?.Clone();
 
         /// <summary>
         /// Looks up and cross-links all fields and nested types.

csharp/src/Google.Protobuf/Reflection/MethodDescriptor.cs

@@ -73,25 +73,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this method.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value method option for this descriptor
+        /// The <c>MethodOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<MethodOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value method option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<MethodOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public MethodOptions Options => (Proto.Options as IDeepCloneable<MethodOptions>)?.Clone();
 
         internal MethodDescriptor(MethodDescriptorProto proto, FileDescriptor file,
                                   ServiceDescriptor parent, int index)

csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs

@@ -117,25 +117,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this oneof.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value oneof option for this descriptor
+        /// The <c>OneofOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<OneofOptions, T> extension)
-        {
-            var value = proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value oneof option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<OneofOptions, T> extension)
-        {
-            return proto.Options.GetExtension(extension).Clone();
-        }
+        public OneofOptions Options => (proto.Options as IDeepCloneable<OneofOptions>)?.Clone();
 
         internal void CrossLink()
         {

csharp/src/Google.Protobuf/Reflection/ServiceDescriptor.cs

@@ -94,25 +94,15 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// The (possibly empty) set of custom options for this service.
         /// </summary>
-        [Obsolete("CustomOptions are obsolete. Use GetOption")]
+        [Obsolete("CustomOptions are obsolete. Use the Options property.")]
         public CustomOptions CustomOptions => new CustomOptions(Proto.Options?._extensions?.ValuesByNumber);
 
         /// <summary>
-        /// Gets a single value service option for this descriptor
+        /// The <c>ServiceOptions</c>, defined in <c>descriptor.proto</c>.
+        /// Custom options can be retrieved as extensions of the returned message.
+        /// NOTE: A defensive copy is created each time this property is retrieved.
         /// </summary>
-        public T GetOption<T>(Extension<ServiceOptions, T> extension)
-        {
-            var value = Proto.Options.GetExtension(extension);
-            return value is IDeepCloneable<T> ? (value as IDeepCloneable<T>).Clone() : value;
-        }
-
-        /// <summary>
-        /// Gets a repeated value service option for this descriptor
-        /// </summary>
-        public RepeatedField<T> GetOption<T>(RepeatedExtension<ServiceOptions, T> extension)
-        {
-            return Proto.Options.GetExtension(extension).Clone();
-        }
+        public ServiceOptions Options => (Proto.Options as IDeepCloneable<ServiceOptions>)?.Clone();
 
         internal void CrossLink()
         {