rust/crates/ra_assists/src/assists/add_impl.rs
2019-09-25 14:29:41 +03:00

78 lines
2.4 KiB
Rust

use format_buf::format;
use hir::db::HirDatabase;
use join_to_string::join;
use ra_syntax::{
ast::{self, AstNode, NameOwner, TypeParamsOwner},
TextUnit,
};
use crate::{Assist, AssistCtx, AssistId};
pub(crate) fn add_impl(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
let nominal = ctx.node_at_offset::<ast::NominalDef>()?;
let name = nominal.name()?;
ctx.add_action(AssistId("add_impl"), "add impl", |edit| {
edit.target(nominal.syntax().text_range());
let type_params = nominal.type_param_list();
let start_offset = nominal.syntax().text_range().end();
let mut buf = String::new();
buf.push_str("\n\nimpl");
if let Some(type_params) = &type_params {
format!(buf, "{}", type_params.syntax());
}
buf.push_str(" ");
buf.push_str(name.text().as_str());
if let Some(type_params) = type_params {
let lifetime_params = type_params
.lifetime_params()
.filter_map(|it| it.lifetime_token())
.map(|it| it.text().clone());
let type_params =
type_params.type_params().filter_map(|it| it.name()).map(|it| it.text().clone());
join(lifetime_params.chain(type_params)).surround_with("<", ">").to_buf(&mut buf);
}
buf.push_str(" {\n");
edit.set_cursor(start_offset + TextUnit::of_str(&buf));
buf.push_str("\n}");
edit.insert(start_offset, buf);
});
ctx.build()
}
#[cfg(test)]
mod tests {
use super::*;
use crate::helpers::{check_assist, check_assist_target};
#[test]
fn test_add_impl() {
check_assist(add_impl, "struct Foo {<|>}\n", "struct Foo {}\n\nimpl Foo {\n<|>\n}\n");
check_assist(
add_impl,
"struct Foo<T: Clone> {<|>}",
"struct Foo<T: Clone> {}\n\nimpl<T: Clone> Foo<T> {\n<|>\n}",
);
check_assist(
add_impl,
"struct Foo<'a, T: Foo<'a>> {<|>}",
"struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n<|>\n}",
);
}
#[test]
fn add_impl_target() {
check_assist_target(
add_impl,
"
struct SomeThingIrrelevant;
/// Has a lifetime parameter
struct Foo<'a, T: Foo<'a>> {<|>}
struct EvenMoreIrrelevant;
",
"/// Has a lifetime parameter
struct Foo<'a, T: Foo<'a>> {}",
);
}
}