rust/crates/ide/src/typing/on_enter.rs
2021-04-12 21:41:44 +02:00

486 lines
9.6 KiB
Rust

//! Handles the `Enter` key press. At the momently, this only continues
//! comments, but should handle indent some time in the future as well.
use ide_db::base_db::{FilePosition, SourceDatabase};
use ide_db::RootDatabase;
use syntax::{
algo::find_node_at_offset,
ast::{self, edit::IndentLevel, AstToken},
AstNode, SmolStr, SourceFile,
SyntaxKind::*,
SyntaxNode, SyntaxToken, TextRange, TextSize, TokenAtOffset,
};
use text_edit::TextEdit;
// Feature: On Enter
//
// rust-analyzer can override kbd:[Enter] key to make it smarter:
//
// - kbd:[Enter] inside triple-slash comments automatically inserts `///`
// - kbd:[Enter] in the middle or after a trailing space in `//` inserts `//`
// - kbd:[Enter] inside `//!` doc comments automatically inserts `//!`
// - kbd:[Enter] after `{` indents contents and closing `}` of single-line block
//
// This action needs to be assigned to shortcut explicitly.
//
// VS Code::
//
// Add the following to `keybindings.json`:
// [source,json]
// ----
// {
// "key": "Enter",
// "command": "rust-analyzer.onEnter",
// "when": "editorTextFocus && !suggestWidgetVisible && editorLangId == rust"
// }
// ----
//
// image::https://user-images.githubusercontent.com/48062697/113065578-04c21800-91b1-11eb-82b8-22b8c481e645.gif[]
pub(crate) fn on_enter(db: &RootDatabase, position: FilePosition) -> Option<TextEdit> {
let parse = db.parse(position.file_id);
let file = parse.tree();
let token = file.syntax().token_at_offset(position.offset).left_biased()?;
if let Some(comment) = ast::Comment::cast(token.clone()) {
return on_enter_in_comment(&comment, &file, position.offset);
}
if token.kind() == L_CURLY {
// Typing enter after the `{` of a block expression, where the `}` is on the same line
if let Some(edit) = find_node_at_offset(file.syntax(), position.offset - TextSize::of('{'))
.and_then(|block| on_enter_in_block(block, position))
{
return Some(edit);
}
}
None
}
fn on_enter_in_comment(
comment: &ast::Comment,
file: &ast::SourceFile,
offset: TextSize,
) -> Option<TextEdit> {
if comment.kind().shape.is_block() {
return None;
}
let prefix = comment.prefix();
let comment_range = comment.syntax().text_range();
if offset < comment_range.start() + TextSize::of(prefix) {
return None;
}
let mut remove_trailing_whitespace = false;
// Continuing single-line non-doc comments (like this one :) ) is annoying
if prefix == "//" && comment_range.end() == offset {
if comment.text().ends_with(' ') {
cov_mark::hit!(continues_end_of_line_comment_with_space);
remove_trailing_whitespace = true;
} else if !followed_by_comment(&comment) {
return None;
}
}
let indent = node_indent(&file, comment.syntax())?;
let inserted = format!("\n{}{} $0", indent, prefix);
let delete = if remove_trailing_whitespace {
let trimmed_len = comment.text().trim_end().len() as u32;
let trailing_whitespace_len = comment.text().len() as u32 - trimmed_len;
TextRange::new(offset - TextSize::from(trailing_whitespace_len), offset)
} else {
TextRange::empty(offset)
};
let edit = TextEdit::replace(delete, inserted);
Some(edit)
}
fn on_enter_in_block(block: ast::BlockExpr, position: FilePosition) -> Option<TextEdit> {
let contents = block_contents(&block)?;
if block.syntax().text().contains_char('\n') {
return None;
}
let indent = IndentLevel::from_node(block.syntax());
let mut edit = TextEdit::insert(position.offset, format!("\n{}$0", indent + 1));
edit.union(TextEdit::insert(contents.text_range().end(), format!("\n{}", indent))).ok()?;
Some(edit)
}
fn block_contents(block: &ast::BlockExpr) -> Option<SyntaxNode> {
let mut node = block.tail_expr().map(|e| e.syntax().clone());
for stmt in block.statements() {
if node.is_some() {
// More than 1 node in the block
return None;
}
node = Some(stmt.syntax().clone());
}
node
}
fn followed_by_comment(comment: &ast::Comment) -> bool {
let ws = match comment.syntax().next_token().and_then(ast::Whitespace::cast) {
Some(it) => it,
None => return false,
};
if ws.spans_multiple_lines() {
return false;
}
ws.syntax().next_token().and_then(ast::Comment::cast).is_some()
}
fn node_indent(file: &SourceFile, token: &SyntaxToken) -> Option<SmolStr> {
let ws = match file.syntax().token_at_offset(token.text_range().start()) {
TokenAtOffset::Between(l, r) => {
assert!(r == *token);
l
}
TokenAtOffset::Single(n) => {
assert!(n == *token);
return Some("".into());
}
TokenAtOffset::None => unreachable!(),
};
if ws.kind() != WHITESPACE {
return None;
}
let text = ws.text();
let pos = text.rfind('\n').map(|it| it + 1).unwrap_or(0);
Some(text[pos..].into())
}
#[cfg(test)]
mod tests {
use stdx::trim_indent;
use test_utils::assert_eq_text;
use crate::fixture;
fn apply_on_enter(before: &str) -> Option<String> {
let (analysis, position) = fixture::position(&before);
let result = analysis.on_enter(position).unwrap()?;
let mut actual = analysis.file_text(position.file_id).unwrap().to_string();
result.apply(&mut actual);
Some(actual)
}
fn do_check(ra_fixture_before: &str, ra_fixture_after: &str) {
let ra_fixture_after = &trim_indent(ra_fixture_after);
let actual = apply_on_enter(ra_fixture_before).unwrap();
assert_eq_text!(ra_fixture_after, &actual);
}
fn do_check_noop(ra_fixture_text: &str) {
assert!(apply_on_enter(ra_fixture_text).is_none())
}
#[test]
fn continues_doc_comment() {
do_check(
r"
/// Some docs$0
fn foo() {
}
",
r"
/// Some docs
/// $0
fn foo() {
}
",
);
do_check(
r"
impl S {
/// Some$0 docs.
fn foo() {}
}
",
r"
impl S {
/// Some
/// $0 docs.
fn foo() {}
}
",
);
do_check(
r"
///$0 Some docs
fn foo() {
}
",
r"
///
/// $0 Some docs
fn foo() {
}
",
);
}
#[test]
fn does_not_continue_before_doc_comment() {
do_check_noop(r"$0//! docz");
}
#[test]
fn continues_another_doc_comment() {
do_check(
r#"
fn main() {
//! Documentation for$0 on enter
let x = 1 + 1;
}
"#,
r#"
fn main() {
//! Documentation for
//! $0 on enter
let x = 1 + 1;
}
"#,
);
}
#[test]
fn continues_code_comment_in_the_middle_of_line() {
do_check(
r"
fn main() {
// Fix$0 me
let x = 1 + 1;
}
",
r"
fn main() {
// Fix
// $0 me
let x = 1 + 1;
}
",
);
}
#[test]
fn continues_code_comment_in_the_middle_several_lines() {
do_check(
r"
fn main() {
// Fix$0
// me
let x = 1 + 1;
}
",
r"
fn main() {
// Fix
// $0
// me
let x = 1 + 1;
}
",
);
}
#[test]
fn does_not_continue_end_of_line_comment() {
do_check_noop(
r"
fn main() {
// Fix me$0
let x = 1 + 1;
}
",
);
}
#[test]
fn continues_end_of_line_comment_with_space() {
cov_mark::check!(continues_end_of_line_comment_with_space);
do_check(
r#"
fn main() {
// Fix me $0
let x = 1 + 1;
}
"#,
r#"
fn main() {
// Fix me
// $0
let x = 1 + 1;
}
"#,
);
}
#[test]
fn trims_all_trailing_whitespace() {
do_check(
"
fn main() {
// Fix me \t\t $0
let x = 1 + 1;
}
",
"
fn main() {
// Fix me
// $0
let x = 1 + 1;
}
",
);
}
#[test]
fn indents_fn_body_block() {
do_check(
r#"
fn f() {$0()}
"#,
r#"
fn f() {
$0()
}
"#,
);
}
#[test]
fn indents_block_expr() {
do_check(
r#"
fn f() {
let x = {$0()};
}
"#,
r#"
fn f() {
let x = {
$0()
};
}
"#,
);
}
#[test]
fn indents_match_arm() {
do_check(
r#"
fn f() {
match 6 {
1 => {$0f()},
_ => (),
}
}
"#,
r#"
fn f() {
match 6 {
1 => {
$0f()
},
_ => (),
}
}
"#,
);
}
#[test]
fn indents_block_with_statement() {
do_check(
r#"
fn f() {$0a = b}
"#,
r#"
fn f() {
$0a = b
}
"#,
);
do_check(
r#"
fn f() {$0fn f() {}}
"#,
r#"
fn f() {
$0fn f() {}
}
"#,
);
}
#[test]
fn indents_nested_blocks() {
do_check(
r#"
fn f() {$0{}}
"#,
r#"
fn f() {
$0{}
}
"#,
);
}
#[test]
fn does_not_indent_empty_block() {
do_check_noop(
r#"
fn f() {$0}
"#,
);
do_check_noop(
r#"
fn f() {{$0}}
"#,
);
}
#[test]
fn does_not_indent_block_with_too_much_content() {
do_check_noop(
r#"
fn f() {$0 a = b; ()}
"#,
);
do_check_noop(
r#"
fn f() {$0 a = b; a = b; }
"#,
);
}
#[test]
fn does_not_indent_multiline_block() {
do_check_noop(
r#"
fn f() {$0
}
"#,
);
do_check_noop(
r#"
fn f() {$0
}
"#,
);
}
}