blob: a70afffa6226600bbf4ab2bf16dc0c2e302025cc [file] [log] [blame]
// Protocol Buffers - Google's data interchange format
// Copyright 2024 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
/// proto! enables the use of Rust struct initialization syntax to create
/// protobuf messages. The macro does its best to try and detect the
/// initialization of submessages, but it is only able to do so while the
/// submessage is being defined as part of the original struct literal.
/// Introducing an expression using () or {} as the value of a field will
/// require another call to this macro in order to return a submessage
/// literal.``` /*
/// Given the following proto definition
/// message Data {
/// int32 number = 1;
/// string letters = 2;
/// Data nested = 3;
/// }
/// */
/// use protobuf::proto;
/// let message = proto!(Data {
/// number: 42,
/// letters: "Hello World",
/// nested: Data {
/// number: {
/// let x = 100;
/// x + 1
/// }
/// }
/// }); ```
#[macro_export]
macro_rules! proto {
($msgtype:ty { $($tt:tt)* }) => {
$crate::proto_internal!($msgtype { $($tt)* })
}
}
#[macro_export(local_inner_macros)]
#[doc(hidden)]
macro_rules! proto_internal {
(@merge $msg:ident $ident:ident : $expr:expr, $($rest:tt)*) => {
proto_internal!(@merge $msg $($rest)*);
};
(@merge $msg:ident $ident:ident : $expr:expr) => {
};
(@merge $msg:ident ..$expr:expr) => {
$msg.merge_from($expr);
};
// nested message,
(@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { $field:ident : $($value:tt)* }, $($rest:tt)*) => {
proto_internal!(@msg $msg $submsg : $($msgtype)::+ { $field : $($value)* });
proto_internal!(@msg $msg $($rest)*);
};
(@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { $field:ident : $($value:tt)* }, $($rest:tt)*) => {
proto_internal!(@msg $msg $submsg : ::$($msgtype)::+ { $field : $($value)* });
proto_internal!(@msg $msg $($rest)*);
};
// nested message
(@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { $field:ident : $($value:tt)* }) => {
{
let mut $msg: <$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
proto_internal!(@merge $msg $field : $($value)*);
proto_internal!(@msg $msg $field : $($value)*);
}
};
(@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { $field:ident : $($value:tt)* }) => {
{
let mut $msg: <::$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
proto_internal!(@merge $msg $field : $($value)*);
proto_internal!(@msg $msg $field : $($value)*);
}
};
// empty nested message,
(@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { }, $($rest:tt)*) => {
proto_internal!(@msg $msg $submsg : $($msgtype)::+ { });
proto_internal!(@msg $msg $($rest)*);
};
(@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { }, $($rest:tt)*) => {
proto_internal!(@msg $msg $submsg : ::$($msgtype)::+ { });
proto_internal!(@msg $msg $($rest)*);
};
// empty nested message
(@msg $msg:ident $submsg:ident : $($msgtype:ident)::+ { }) => {
{
let mut $msg: <$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
}
};
(@msg $msg:ident $submsg:ident : ::$($msgtype:ident)::+ { }) => {
{
let mut $msg: <::$($msgtype)::+ as $crate::MutProxied>::Mut<'_> = $crate::__internal::paste!($msg.[<$submsg _mut>]());
}
};
// field: expr,
(@msg $msg:ident $ident:ident : $expr:expr, $($rest:tt)*) => {
// delegate without ,
proto_internal!(@msg $msg $ident : $expr);
proto_internal!(@msg $msg $($rest)*);
};
// field: expr
(@msg $msg:ident $ident:ident : $expr:expr) => {
$crate::__internal::paste!($msg.[<set_ $ident>]($expr));
};
(@msg $msg:ident ..$expr:expr) => {
};
(@msg $msg:ident) => {};
(@merge $msg:ident) => {};
// entry point
($msgtype:ty { $($tt:tt)* }) => {
{
let mut message = <$msgtype>::new();
proto_internal!(@merge message $($tt)*);
proto_internal!(@msg message $($tt)*);
message
}
};
}