mirror of
https://github.com/LemmyNet/lemmy.git
synced 2025-04-27 13:14:44 +00:00
67 lines
2.3 KiB
Rust
67 lines
2.3 KiB
Rust
/// `macro_rules_attribute::derive(WithoutId!)` generates a variant of the struct with
|
|
/// `WithoutId` added to the name and no `id` field.
|
|
///
|
|
/// This is useful for making less redundant selections of multiple joined tables.
|
|
/// For example, selecting both `comment::post_id` and `post::id` is redundant if they
|
|
/// have the same value. In this case, the selection of `post::id` can be avoided by selecting
|
|
/// `PostWithoutId::as_select()` instead of `post::all_columns`.
|
|
///
|
|
/// This macro generates an `into_full` method, which converts to the sturct with `id`.
|
|
/// For example, `PostWithoutId` would have this:
|
|
///
|
|
/// `pub fn into_full(self, id: PostId) -> Post`
|
|
///
|
|
/// The `id` value can come from a column in another table, like `comment::post_id`.
|
|
///
|
|
/// The generated struct implements `Selectable` and `Queryable`.
|
|
macro_rules! WithoutId {
|
|
(
|
|
#[diesel(table_name = $table_name:ident)]
|
|
$(#[$_struct_meta:meta])*
|
|
$vis:vis struct $struct_name:ident {
|
|
$(#[$_id_meta:meta])*
|
|
$_id_vis:vis id: $id_type:ty,
|
|
$(
|
|
// TODO: more flexible attribute matching
|
|
$(#[doc = $_doc1:tt])*
|
|
$(#[cfg($($cfgtt:tt)*)])*
|
|
$(#[cfg_attr($($cfgattrtt:tt)*)])*
|
|
$(#[serde($($serdett:tt)*)])*
|
|
$(#[doc = $_doc2:tt])*
|
|
$field_vis:vis $field_name:ident : $field_type:ty,
|
|
)*
|
|
}
|
|
) => {
|
|
::paste::paste! {
|
|
// TODO: remove serde derives
|
|
#[derive(::diesel::Queryable, ::diesel::Selectable, ::serde::Serialize, ::serde::Deserialize)]
|
|
#[diesel(table_name = $table_name)]
|
|
$vis struct [<$struct_name WithoutId>] {
|
|
$(
|
|
$(#[cfg($($cfgtt)*)])*
|
|
$field_vis $field_name : $field_type,
|
|
)*
|
|
}
|
|
|
|
impl [<$struct_name WithoutId>] {
|
|
pub fn into_full(self, id: $id_type) -> $struct_name {
|
|
$struct_name {
|
|
id,
|
|
$($(#[cfg($($cfgtt)*)])* $field_name : self.$field_name,)*
|
|
}
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
// Keep on removing the first attribute until `diesel(table_name = ...)` becomes
|
|
// the first, which will cause the first pattern to be matched.
|
|
(#[$_meta:meta] $($remaining:tt)*) => {
|
|
WithoutId!($($remaining)*);
|
|
};
|
|
|
|
// This pattern is matched when there's no attributes.
|
|
($_vis:vis struct $($_tt:tt)*) => {
|
|
::std::compile_error!("`#[diesel(table_name = ...)]` is missing");
|
|
};
|
|
}
|