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 test_merge_single_wildcard_diff_prefixes() { check_assist( merge_imports, r" use std<|>::cell::*; use std::str; ", r" use std<|>::{cell::*, str}; ", ) } #[test] fn test_merge_both_wildcard_diff_prefixes() { check_assist( merge_imports, r" use std<|>::cell::*; use std::str::*; ", r" use std<|>::{cell::*, str::*}; ", ) } #[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}, }; ", ); } }