rust/crates/ide-assists/src/handlers/generate_new.rs

499 lines
9.8 KiB
Rust

use ide_db::{
imports::import_assets::item_for_path_search, use_trivial_contructor::use_trivial_constructor,
};
use itertools::Itertools;
use stdx::format_to;
use syntax::ast::{self, AstNode, HasName, HasVisibility, StructKind};
use crate::{
utils::{find_impl_block_start, find_struct_impl, generate_impl_text},
AssistContext, AssistId, AssistKind, Assists,
};
// Assist: generate_new
//
// Adds a `fn new` for a type.
//
// ```
// struct Ctx<T: Clone> {
// data: T,$0
// }
// ```
// ->
// ```
// struct Ctx<T: Clone> {
// data: T,
// }
//
// impl<T: Clone> Ctx<T> {
// fn $0new(data: T) -> Self { Self { data } }
// }
// ```
pub(crate) fn generate_new(acc: &mut Assists, ctx: &AssistContext<'_>) -> Option<()> {
let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
// We want to only apply this to non-union structs with named fields
let field_list = match strukt.kind() {
StructKind::Record(named) => named,
_ => return None,
};
// Return early if we've found an existing new fn
let impl_def = find_struct_impl(ctx, &ast::Adt::Struct(strukt.clone()), "new")?;
let current_module = ctx.sema.scope(strukt.syntax())?.module();
let target = strukt.syntax().text_range();
acc.add(AssistId("generate_new", AssistKind::Generate), "Generate `new`", target, |builder| {
let mut buf = String::with_capacity(512);
if impl_def.is_some() {
buf.push('\n');
}
let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
let trivial_constructors = field_list
.fields()
.map(|f| {
let ty = ctx.sema.resolve_type(&f.ty()?)?;
let item_in_ns = hir::ItemInNs::from(hir::ModuleDef::from(ty.as_adt()?));
let type_path = current_module.find_use_path(
ctx.sema.db,
item_for_path_search(ctx.sema.db, item_in_ns)?,
ctx.config.prefer_core,
)?;
let expr = use_trivial_constructor(
&ctx.sema.db,
ide_db::helpers::mod_path_to_ast(&type_path),
&ty,
)?;
Some(format!("{}: {}", f.name()?.syntax(), expr))
})
.collect::<Vec<_>>();
let params = field_list
.fields()
.enumerate()
.filter_map(|(i, f)| {
if trivial_constructors[i].is_none() {
Some(format!("{}: {}", f.name()?.syntax(), f.ty()?.syntax()))
} else {
None
}
})
.format(", ");
let fields = field_list
.fields()
.enumerate()
.filter_map(|(i, f)| {
let contructor = trivial_constructors[i].clone();
if contructor.is_some() {
contructor
} else {
Some(f.name()?.to_string())
}
})
.format(", ");
format_to!(buf, " {}fn new({}) -> Self {{ Self {{ {} }} }}", vis, params, fields);
let start_offset = impl_def
.and_then(|impl_def| find_impl_block_start(impl_def, &mut buf))
.unwrap_or_else(|| {
buf = generate_impl_text(&ast::Adt::Struct(strukt.clone()), &buf);
strukt.syntax().text_range().end()
});
match ctx.config.snippet_cap {
None => builder.insert(start_offset, buf),
Some(cap) => {
buf = buf.replace("fn new", "fn $0new");
builder.insert_snippet(cap, start_offset, buf);
}
}
})
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target};
use super::*;
#[test]
fn test_generate_new_with_zst_fields() {
check_assist(
generate_new,
r#"
struct Empty;
struct Foo { empty: Empty $0}
"#,
r#"
struct Empty;
struct Foo { empty: Empty }
impl Foo {
fn $0new() -> Self { Self { empty: Empty } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Empty;
struct Foo { baz: String, empty: Empty $0}
"#,
r#"
struct Empty;
struct Foo { baz: String, empty: Empty }
impl Foo {
fn $0new(baz: String) -> Self { Self { baz, empty: Empty } }
}
"#,
);
check_assist(
generate_new,
r#"
enum Empty { Bar }
struct Foo { empty: Empty $0}
"#,
r#"
enum Empty { Bar }
struct Foo { empty: Empty }
impl Foo {
fn $0new() -> Self { Self { empty: Empty::Bar } }
}
"#,
);
// make sure the assist only works on unit variants
check_assist(
generate_new,
r#"
struct Empty {}
struct Foo { empty: Empty $0}
"#,
r#"
struct Empty {}
struct Foo { empty: Empty }
impl Foo {
fn $0new(empty: Empty) -> Self { Self { empty } }
}
"#,
);
check_assist(
generate_new,
r#"
enum Empty { Bar {} }
struct Foo { empty: Empty $0}
"#,
r#"
enum Empty { Bar {} }
struct Foo { empty: Empty }
impl Foo {
fn $0new(empty: Empty) -> Self { Self { empty } }
}
"#,
);
}
#[test]
fn test_generate_new() {
check_assist(
generate_new,
r#"
struct Foo {$0}
"#,
r#"
struct Foo {}
impl Foo {
fn $0new() -> Self { Self { } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo<T: Clone> {$0}
"#,
r#"
struct Foo<T: Clone> {}
impl<T: Clone> Foo<T> {
fn $0new() -> Self { Self { } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo<'a, T: Foo<'a>> {$0}
"#,
r#"
struct Foo<'a, T: Foo<'a>> {}
impl<'a, T: Foo<'a>> Foo<'a, T> {
fn $0new() -> Self { Self { } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo { baz: String $0}
"#,
r#"
struct Foo { baz: String }
impl Foo {
fn $0new(baz: String) -> Self { Self { baz } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo { baz: String, qux: Vec<i32> $0}
"#,
r#"
struct Foo { baz: String, qux: Vec<i32> }
impl Foo {
fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
}
"#,
);
}
#[test]
fn check_that_visibility_modifiers_dont_get_brought_in() {
check_assist(
generate_new,
r#"
struct Foo { pub baz: String, pub qux: Vec<i32> $0}
"#,
r#"
struct Foo { pub baz: String, pub qux: Vec<i32> }
impl Foo {
fn $0new(baz: String, qux: Vec<i32>) -> Self { Self { baz, qux } }
}
"#,
);
}
#[test]
fn check_it_reuses_existing_impls() {
check_assist(
generate_new,
r#"
struct Foo {$0}
impl Foo {}
"#,
r#"
struct Foo {}
impl Foo {
fn $0new() -> Self { Self { } }
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo {$0}
impl Foo {
fn qux(&self) {}
}
"#,
r#"
struct Foo {}
impl Foo {
fn $0new() -> Self { Self { } }
fn qux(&self) {}
}
"#,
);
check_assist(
generate_new,
r#"
struct Foo {$0}
impl Foo {
fn qux(&self) {}
fn baz() -> i32 {
5
}
}
"#,
r#"
struct Foo {}
impl Foo {
fn $0new() -> Self { Self { } }
fn qux(&self) {}
fn baz() -> i32 {
5
}
}
"#,
);
}
#[test]
fn check_visibility_of_new_fn_based_on_struct() {
check_assist(
generate_new,
r#"
pub struct Foo {$0}
"#,
r#"
pub struct Foo {}
impl Foo {
pub fn $0new() -> Self { Self { } }
}
"#,
);
check_assist(
generate_new,
r#"
pub(crate) struct Foo {$0}
"#,
r#"
pub(crate) struct Foo {}
impl Foo {
pub(crate) fn $0new() -> Self { Self { } }
}
"#,
);
}
#[test]
fn generate_new_not_applicable_if_fn_exists() {
check_assist_not_applicable(
generate_new,
r#"
struct Foo {$0}
impl Foo {
fn new() -> Self {
Self
}
}
"#,
);
check_assist_not_applicable(
generate_new,
r#"
struct Foo {$0}
impl Foo {
fn New() -> Self {
Self
}
}
"#,
);
}
#[test]
fn generate_new_target() {
check_assist_target(
generate_new,
r#"
struct SomeThingIrrelevant;
/// Has a lifetime parameter
struct Foo<'a, T: Foo<'a>> {$0}
struct EvenMoreIrrelevant;
"#,
"/// Has a lifetime parameter
struct Foo<'a, T: Foo<'a>> {}",
);
}
#[test]
fn test_unrelated_new() {
check_assist(
generate_new,
r#"
pub struct AstId<N: AstNode> {
file_id: HirFileId,
file_ast_id: FileAstId<N>,
}
impl<N: AstNode> AstId<N> {
pub fn new(file_id: HirFileId, file_ast_id: FileAstId<N>) -> AstId<N> {
AstId { file_id, file_ast_id }
}
}
pub struct Source<T> {
pub file_id: HirFileId,$0
pub ast: T,
}
impl<T> Source<T> {
pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> Source<U> {
Source { file_id: self.file_id, ast: f(self.ast) }
}
}
"#,
r#"
pub struct AstId<N: AstNode> {
file_id: HirFileId,
file_ast_id: FileAstId<N>,
}
impl<N: AstNode> AstId<N> {
pub fn new(file_id: HirFileId, file_ast_id: FileAstId<N>) -> AstId<N> {
AstId { file_id, file_ast_id }
}
}
pub struct Source<T> {
pub file_id: HirFileId,
pub ast: T,
}
impl<T> Source<T> {
pub fn $0new(file_id: HirFileId, ast: T) -> Self { Self { file_id, ast } }
pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> Source<U> {
Source { file_id: self.file_id, ast: f(self.ast) }
}
}
"#,
);
}
}