From fc34403018079ea053f26d0a31b7517053c7dd8c Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Thu, 13 Aug 2020 17:33:38 +0200 Subject: Rename ra_assists -> assists --- crates/assists/src/handlers/generate_new.rs | 421 ++++++++++++++++++++++++++++ 1 file changed, 421 insertions(+) create mode 100644 crates/assists/src/handlers/generate_new.rs (limited to 'crates/assists/src/handlers/generate_new.rs') diff --git a/crates/assists/src/handlers/generate_new.rs b/crates/assists/src/handlers/generate_new.rs new file mode 100644 index 000000000..7db10f276 --- /dev/null +++ b/crates/assists/src/handlers/generate_new.rs @@ -0,0 +1,421 @@ +use hir::Adt; +use itertools::Itertools; +use stdx::format_to; +use syntax::{ + ast::{self, AstNode, GenericParamsOwner, NameOwner, StructKind, VisibilityOwner}, + T, +}; + +use crate::{AssistContext, AssistId, AssistKind, Assists}; + +// Assist: generate_new +// +// Adds a new inherent impl for a type. +// +// ``` +// struct Ctx { +// data: T,<|> +// } +// ``` +// -> +// ``` +// struct Ctx { +// data: T, +// } +// +// impl Ctx { +// 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::()?; + + // 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, &strukt)?; + + 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 params = field_list + .fields() + .filter_map(|f| Some(format!("{}: {}", f.name()?.syntax(), f.ty()?.syntax()))) + .format(", "); + let fields = field_list.fields().filter_map(|f| f.name()).format(", "); + + format_to!(buf, " {}fn new({}) -> Self {{ Self {{ {} }} }}", vis, params, fields); + + let start_offset = impl_def + .and_then(|impl_def| { + buf.push('\n'); + let start = impl_def + .syntax() + .descendants_with_tokens() + .find(|t| t.kind() == T!['{'])? + .text_range() + .end(); + + Some(start) + }) + .unwrap_or_else(|| { + buf = generate_impl_text(&strukt, &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); + } + } + }) +} + +// Generates the surrounding `impl Type { }` including type and lifetime +// parameters +fn generate_impl_text(strukt: &ast::Struct, code: &str) -> String { + let type_params = strukt.generic_param_list(); + let mut buf = String::with_capacity(code.len()); + buf.push_str("\n\nimpl"); + if let Some(type_params) = &type_params { + format_to!(buf, "{}", type_params.syntax()); + } + buf.push_str(" "); + buf.push_str(strukt.name().unwrap().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()); + format_to!(buf, "<{}>", lifetime_params.chain(type_params).format(", ")) + } + + format_to!(buf, " {{\n{}\n}}\n", code); + + buf +} + +// Uses a syntax-driven approach to find any impl blocks for the struct that +// exist within the module/file +// +// Returns `None` if we've found an existing `new` fn +// +// FIXME: change the new fn checking to a more semantic approach when that's more +// viable (e.g. we process proc macros, etc) +fn find_struct_impl(ctx: &AssistContext, strukt: &ast::Struct) -> Option> { + let db = ctx.db(); + let module = strukt.syntax().ancestors().find(|node| { + ast::Module::can_cast(node.kind()) || ast::SourceFile::can_cast(node.kind()) + })?; + + let struct_def = ctx.sema.to_def(strukt)?; + + let block = module.descendants().filter_map(ast::Impl::cast).find_map(|impl_blk| { + let blk = ctx.sema.to_def(&impl_blk)?; + + // FIXME: handle e.g. `struct S; impl S {}` + // (we currently use the wrong type parameter) + // also we wouldn't want to use e.g. `impl S` + let same_ty = match blk.target_ty(db).as_adt() { + Some(def) => def == Adt::Struct(struct_def), + None => false, + }; + let not_trait_impl = blk.target_trait(db).is_none(); + + if !(same_ty && not_trait_impl) { + None + } else { + Some(impl_blk) + } + }); + + if let Some(ref impl_blk) = block { + if has_new_fn(impl_blk) { + return None; + } + } + + Some(block) +} + +fn has_new_fn(imp: &ast::Impl) -> bool { + if let Some(il) = imp.assoc_item_list() { + for item in il.assoc_items() { + if let ast::AssocItem::Fn(f) = item { + if let Some(name) = f.name() { + if name.text().eq_ignore_ascii_case("new") { + return true; + } + } + } + } + } + + false +} + +#[cfg(test)] +mod tests { + use crate::tests::{check_assist, check_assist_not_applicable, check_assist_target}; + + use super::*; + + #[test] + #[rustfmt::skip] + fn test_generate_new() { + // Check output of generation + check_assist( + generate_new, +"struct Foo {<|>}", +"struct Foo {} + +impl Foo { + fn $0new() -> Self { Self { } } +} +", + ); + check_assist( + generate_new, +"struct Foo {<|>}", +"struct Foo {} + +impl Foo { + fn $0new() -> Self { Self { } } +} +", + ); + check_assist( + generate_new, +"struct Foo<'a, T: Foo<'a>> {<|>}", +"struct Foo<'a, T: Foo<'a>> {} + +impl<'a, T: Foo<'a>> Foo<'a, T> { + fn $0new() -> Self { Self { } } +} +", + ); + check_assist( + generate_new, +"struct Foo { baz: String <|>}", +"struct Foo { baz: String } + +impl Foo { + fn $0new(baz: String) -> Self { Self { baz } } +} +", + ); + check_assist( + generate_new, +"struct Foo { baz: String, qux: Vec <|>}", +"struct Foo { baz: String, qux: Vec } + +impl Foo { + fn $0new(baz: String, qux: Vec) -> Self { Self { baz, qux } } +} +", + ); + + // Check that visibility modifiers don't get brought in for fields + check_assist( + generate_new, +"struct Foo { pub baz: String, pub qux: Vec <|>}", +"struct Foo { pub baz: String, pub qux: Vec } + +impl Foo { + fn $0new(baz: String, qux: Vec) -> Self { Self { baz, qux } } +} +", + ); + + // Check that it reuses existing impls + check_assist( + generate_new, +"struct Foo {<|>} + +impl Foo {} +", +"struct Foo {} + +impl Foo { + fn $0new() -> Self { Self { } } +} +", + ); + check_assist( + generate_new, +"struct Foo {<|>} + +impl Foo { + fn qux(&self) {} +} +", +"struct Foo {} + +impl Foo { + fn $0new() -> Self { Self { } } + + fn qux(&self) {} +} +", + ); + + check_assist( + generate_new, +"struct Foo {<|>} + +impl Foo { + fn qux(&self) {} + fn baz() -> i32 { + 5 + } +} +", +"struct Foo {} + +impl Foo { + fn $0new() -> Self { Self { } } + + fn qux(&self) {} + fn baz() -> i32 { + 5 + } +} +", + ); + + // Check visibility of new fn based on struct + check_assist( + generate_new, +"pub struct Foo {<|>}", +"pub struct Foo {} + +impl Foo { + pub fn $0new() -> Self { Self { } } +} +", + ); + check_assist( + generate_new, +"pub(crate) struct Foo {<|>}", +"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, + " +struct Foo {<|>} + +impl Foo { + fn new() -> Self { + Self + } +}", + ); + + check_assist_not_applicable( + generate_new, + " +struct Foo {<|>} + +impl Foo { + fn New() -> Self { + Self + } +}", + ); + } + + #[test] + fn generate_new_target() { + check_assist_target( + generate_new, + " +struct SomeThingIrrelevant; +/// Has a lifetime parameter +struct Foo<'a, T: Foo<'a>> {<|>} +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 { + file_id: HirFileId, + file_ast_id: FileAstId, +} + +impl AstId { + pub fn new(file_id: HirFileId, file_ast_id: FileAstId) -> AstId { + AstId { file_id, file_ast_id } + } +} + +pub struct Source { + pub file_id: HirFileId,<|> + pub ast: T, +} + +impl Source { + pub fn map U, U>(self, f: F) -> Source { + Source { file_id: self.file_id, ast: f(self.ast) } + } +} +"##, + r##" +pub struct AstId { + file_id: HirFileId, + file_ast_id: FileAstId, +} + +impl AstId { + pub fn new(file_id: HirFileId, file_ast_id: FileAstId) -> AstId { + AstId { file_id, file_ast_id } + } +} + +pub struct Source { + pub file_id: HirFileId, + pub ast: T, +} + +impl Source { + pub fn $0new(file_id: HirFileId, ast: T) -> Self { Self { file_id, ast } } + + pub fn map U, U>(self, f: F) -> Source { + Source { file_id: self.file_id, ast: f(self.ast) } + } +} +"##, + ); + } +} -- cgit v1.2.3