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|
use std::iter::successors;
use ra_syntax::{
algo::{neighbor, SyntaxRewriter},
ast::{self, edit::AstNodeEdit, make},
AstNode, Direction, InsertPosition, SyntaxElement, T,
};
use crate::{Assist, AssistCtx, AssistId};
// Assist: merge_imports
//
// Merges two imports with a common prefix.
//
// ```
// use std::<|>fmt::Formatter;
// use std::io;
// ```
// ->
// ```
// use std::{fmt::Formatter, io};
// ```
pub(crate) fn merge_imports(ctx: AssistCtx) -> Option<Assist> {
let tree: ast::UseTree = ctx.find_node_at_offset()?;
let mut rewriter = SyntaxRewriter::default();
let mut offset = ctx.frange.range.start();
if let Some(use_item) = tree.syntax().parent().and_then(ast::UseItem::cast) {
let (merged, to_delete) = next_prev()
.filter_map(|dir| neighbor(&use_item, dir))
.filter_map(|it| Some((it.clone(), it.use_tree()?)))
.find_map(|(use_item, use_tree)| {
Some((try_merge_trees(&tree, &use_tree)?, use_item.clone()))
})?;
rewriter.replace_ast(&tree, &merged);
rewriter += to_delete.remove();
if to_delete.syntax().text_range().end() < offset {
offset -= to_delete.syntax().text_range().len();
}
} else {
let (merged, to_delete) = next_prev()
.filter_map(|dir| neighbor(&tree, dir))
.find_map(|use_tree| Some((try_merge_trees(&tree, &use_tree)?, use_tree.clone())))?;
rewriter.replace_ast(&tree, &merged);
rewriter += to_delete.remove();
if to_delete.syntax().text_range().end() < offset {
offset -= to_delete.syntax().text_range().len();
}
};
ctx.add_assist(AssistId("merge_imports"), "Merge imports", |edit| {
edit.rewrite(rewriter);
// FIXME: we only need because our diff is imprecise
edit.set_cursor(offset);
})
}
fn next_prev() -> impl Iterator<Item = Direction> {
[Direction::Next, Direction::Prev].iter().copied()
}
fn try_merge_trees(old: &ast::UseTree, new: &ast::UseTree) -> Option<ast::UseTree> {
let lhs_path = old.path()?;
let rhs_path = new.path()?;
let (lhs_prefix, rhs_prefix) = common_prefix(&lhs_path, &rhs_path)?;
let lhs = old.split_prefix(&lhs_prefix);
let rhs = new.split_prefix(&rhs_prefix);
let mut to_insert: Vec<SyntaxElement> = Vec::new();
to_insert.push(make::token(T![,]).into());
to_insert.push(make::tokens::single_space().into());
to_insert.extend(
rhs.use_tree_list()?
.syntax()
.children_with_tokens()
.filter(|it| it.kind() != T!['{'] && it.kind() != T!['}']),
);
let use_tree_list = lhs.use_tree_list()?;
let pos = InsertPosition::Before(use_tree_list.r_curly()?.into());
let use_tree_list = use_tree_list.insert_children(pos, to_insert);
Some(lhs.with_use_tree_list(use_tree_list))
}
fn common_prefix(lhs: &ast::Path, rhs: &ast::Path) -> Option<(ast::Path, ast::Path)> {
let mut res = None;
let mut lhs_curr = first_path(&lhs);
let mut rhs_curr = first_path(&rhs);
loop {
match (lhs_curr.segment(), rhs_curr.segment()) {
(Some(lhs), Some(rhs)) if lhs.syntax().text() == rhs.syntax().text() => (),
_ => break,
}
res = Some((lhs_curr.clone(), rhs_curr.clone()));
match (lhs_curr.parent_path(), rhs_curr.parent_path()) {
(Some(lhs), Some(rhs)) => {
lhs_curr = lhs;
rhs_curr = rhs;
}
_ => break,
}
}
res
}
fn first_path(path: &ast::Path) -> ast::Path {
successors(Some(path.clone()), |it| it.qualifier()).last().unwrap()
}
#[cfg(test)]
mod tests {
use crate::helpers::check_assist;
use super::*;
#[test]
fn test_merge_first() {
check_assist(
merge_imports,
r"
use std::fmt<|>::Debug;
use std::fmt::Display;
",
r"
use std::fmt<|>::{Debug, Display};
",
)
}
#[test]
fn test_merge_second() {
check_assist(
merge_imports,
r"
use std::fmt::Debug;
use std::fmt<|>::Display;
",
r"
use std::fmt:<|>:{Display, Debug};
",
);
}
#[test]
fn test_merge_nested() {
check_assist(
merge_imports,
r"
use std::{fmt<|>::Debug, fmt::Display};
",
r"
use std::{fmt<|>::{Debug, Display}};
",
);
check_assist(
merge_imports,
r"
use std::{fmt::Debug, fmt<|>::Display};
",
r"
use std::{fmt::<|>{Display, Debug}};
",
);
}
#[test]
fn removes_just_enough_whitespace() {
check_assist(
merge_imports,
r"
use foo<|>::bar;
use foo::baz;
/// Doc comment
",
r"
use foo<|>::{bar, baz};
/// Doc comment
",
);
}
#[test]
fn works_with_trailing_comma() {
check_assist(
merge_imports,
r"
use {
foo<|>::bar,
foo::baz,
};
",
r"
use {
foo<|>::{bar, baz},
};
",
);
check_assist(
merge_imports,
r"
use {
foo::baz,
foo<|>::bar,
};
",
r"
use {
foo::{bar<|>, baz},
};
",
);
}
}
|
