rust/crates/ra_ide/src/typing.rs
2020-04-10 16:10:28 +02:00

357 lines
9.2 KiB
Rust

//! This module handles auto-magic editing actions applied together with users
//! edits. For example, if the user typed
//!
//! ```text
//! foo
//! .bar()
//! .baz()
//! | // <- cursor is here
//! ```
//!
//! and types `.` next, we want to indent the dot.
//!
//! Language server executes such typing assists synchronously. That is, they
//! block user's typing and should be pretty fast for this reason!
mod on_enter;
use ra_db::{FilePosition, SourceDatabase};
use ra_fmt::leading_indent;
use ra_ide_db::RootDatabase;
use ra_syntax::{
algo::find_node_at_offset,
ast::{self, AstToken},
AstNode, SourceFile, TextRange, TextUnit,
};
use ra_text_edit::TextEdit;
use crate::{source_change::SingleFileChange, SourceChange};
pub(crate) use on_enter::on_enter;
pub(crate) const TRIGGER_CHARS: &str = ".=>";
pub(crate) fn on_char_typed(
db: &RootDatabase,
position: FilePosition,
char_typed: char,
) -> Option<SourceChange> {
assert!(TRIGGER_CHARS.contains(char_typed));
let file = &db.parse(position.file_id).tree();
assert_eq!(file.syntax().text().char_at(position.offset), Some(char_typed));
let single_file_change = on_char_typed_inner(file, position.offset, char_typed)?;
Some(single_file_change.into_source_change(position.file_id))
}
fn on_char_typed_inner(
file: &SourceFile,
offset: TextUnit,
char_typed: char,
) -> Option<SingleFileChange> {
assert!(TRIGGER_CHARS.contains(char_typed));
match char_typed {
'.' => on_dot_typed(file, offset),
'=' => on_eq_typed(file, offset),
'>' => on_arrow_typed(file, offset),
_ => unreachable!(),
}
}
/// Returns an edit which should be applied after `=` was typed. Primarily,
/// this works when adding `let =`.
// FIXME: use a snippet completion instead of this hack here.
fn on_eq_typed(file: &SourceFile, offset: TextUnit) -> Option<SingleFileChange> {
assert_eq!(file.syntax().text().char_at(offset), Some('='));
let let_stmt: ast::LetStmt = find_node_at_offset(file.syntax(), offset)?;
if let_stmt.semicolon_token().is_some() {
return None;
}
if let Some(expr) = let_stmt.initializer() {
let expr_range = expr.syntax().text_range();
if expr_range.contains(offset) && offset != expr_range.start() {
return None;
}
if file.syntax().text().slice(offset..expr_range.start()).contains_char('\n') {
return None;
}
} else {
return None;
}
let offset = let_stmt.syntax().text_range().end();
Some(SingleFileChange {
label: "add semicolon".to_string(),
edit: TextEdit::insert(offset, ";".to_string()),
cursor_position: None,
})
}
/// Returns an edit which should be applied when a dot ('.') is typed on a blank line, indenting the line appropriately.
fn on_dot_typed(file: &SourceFile, offset: TextUnit) -> Option<SingleFileChange> {
assert_eq!(file.syntax().text().char_at(offset), Some('.'));
let whitespace =
file.syntax().token_at_offset(offset).left_biased().and_then(ast::Whitespace::cast)?;
let current_indent = {
let text = whitespace.text();
let newline = text.rfind('\n')?;
&text[newline + 1..]
};
let current_indent_len = TextUnit::of_str(current_indent);
// Make sure dot is a part of call chain
let field_expr = ast::FieldExpr::cast(whitespace.syntax().parent())?;
let prev_indent = leading_indent(field_expr.syntax())?;
let target_indent = format!(" {}", prev_indent);
let target_indent_len = TextUnit::of_str(&target_indent);
if current_indent_len == target_indent_len {
return None;
}
Some(SingleFileChange {
label: "reindent dot".to_string(),
edit: TextEdit::replace(
TextRange::from_to(offset - current_indent_len, offset),
target_indent,
),
cursor_position: Some(
offset + target_indent_len - current_indent_len + TextUnit::of_char('.'),
),
})
}
/// Adds a space after an arrow when `fn foo() { ... }` is turned into `fn foo() -> { ... }`
fn on_arrow_typed(file: &SourceFile, offset: TextUnit) -> Option<SingleFileChange> {
let file_text = file.syntax().text();
assert_eq!(file_text.char_at(offset), Some('>'));
let after_arrow = offset + TextUnit::of_char('>');
if file_text.char_at(after_arrow) != Some('{') {
return None;
}
if find_node_at_offset::<ast::RetType>(file.syntax(), offset).is_none() {
return None;
}
Some(SingleFileChange {
label: "add space after return type".to_string(),
edit: TextEdit::insert(after_arrow, " ".to_string()),
cursor_position: Some(after_arrow),
})
}
#[cfg(test)]
mod tests {
use test_utils::{assert_eq_text, extract_offset};
use super::*;
fn do_type_char(char_typed: char, before: &str) -> Option<(String, SingleFileChange)> {
let (offset, before) = extract_offset(before);
let edit = TextEdit::insert(offset, char_typed.to_string());
let before = edit.apply(&before);
let parse = SourceFile::parse(&before);
on_char_typed_inner(&parse.tree(), offset, char_typed)
.map(|it| (it.edit.apply(&before), it))
}
fn type_char(char_typed: char, before: &str, after: &str) {
let (actual, file_change) = do_type_char(char_typed, before)
.unwrap_or_else(|| panic!("typing `{}` did nothing", char_typed));
if after.contains("<|>") {
let (offset, after) = extract_offset(after);
assert_eq_text!(&after, &actual);
assert_eq!(file_change.cursor_position, Some(offset))
} else {
assert_eq_text!(after, &actual);
}
}
fn type_char_noop(char_typed: char, before: &str) {
let file_change = do_type_char(char_typed, before);
assert!(file_change.is_none())
}
#[test]
fn test_on_eq_typed() {
// do_check(r"
// fn foo() {
// let foo =<|>
// }
// ", r"
// fn foo() {
// let foo =;
// }
// ");
type_char(
'=',
r"
fn foo() {
let foo <|> 1 + 1
}
",
r"
fn foo() {
let foo = 1 + 1;
}
",
);
// do_check(r"
// fn foo() {
// let foo =<|>
// let bar = 1;
// }
// ", r"
// fn foo() {
// let foo =;
// let bar = 1;
// }
// ");
}
#[test]
fn indents_new_chain_call() {
type_char(
'.',
r"
fn main() {
xs.foo()
<|>
}
",
r"
fn main() {
xs.foo()
.
}
",
);
type_char_noop(
'.',
r"
fn main() {
xs.foo()
<|>
}
",
)
}
#[test]
fn indents_new_chain_call_with_semi() {
type_char(
'.',
r"
fn main() {
xs.foo()
<|>;
}
",
r"
fn main() {
xs.foo()
.;
}
",
);
type_char_noop(
'.',
r"
fn main() {
xs.foo()
<|>;
}
",
)
}
#[test]
fn indents_continued_chain_call() {
type_char(
'.',
r"
fn main() {
xs.foo()
.first()
<|>
}
",
r"
fn main() {
xs.foo()
.first()
.
}
",
);
type_char_noop(
'.',
r"
fn main() {
xs.foo()
.first()
<|>
}
",
);
}
#[test]
fn indents_middle_of_chain_call() {
type_char(
'.',
r"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
<|>
.nth(92)
.unwrap();
}
",
r"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
.
.nth(92)
.unwrap();
}
",
);
type_char_noop(
'.',
r"
fn source_impl() {
let var = enum_defvariant_list().unwrap()
<|>
.nth(92)
.unwrap();
}
",
);
}
#[test]
fn dont_indent_freestanding_dot() {
type_char_noop(
'.',
r"
fn main() {
<|>
}
",
);
type_char_noop(
'.',
r"
fn main() {
<|>
}
",
);
}
#[test]
fn adds_space_after_return_type() {
type_char('>', "fn foo() -<|>{ 92 }", "fn foo() -><|> { 92 }")
}
}