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improve ordered use tree merging implementation

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This commit is contained in:
davidsemakula 2024-01-14 19:49:50 +03:00
parent db3f0f1761
commit d4b43d5a51
1 changed files with 50 additions and 67 deletions
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109
crates/ide-db/src/imports/merge_imports.rs
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@ -1,14 +1,14 @@
//! Handle syntactic aspects of merging UseTrees.
use std::cmp::Ordering;
use std::iter::{empty, successors};
use std::iter::empty;
use itertools::{EitherOrBoth, Itertools};
use parser::{SyntaxKind, T};
use rustc_hash::{FxHashMap, FxHashSet};
use parser::T;
use syntax::{
algo,
ast::{self, make, AstNode, HasAttrs, HasName, HasVisibility, PathSegmentKind},
ted::{self, Position},
SyntaxElement, TokenText,
Direction, TokenText,
};
use crate::syntax_helpers::node_ext::vis_eq;
@ -101,22 +101,6 @@ fn recursive_merge(lhs: &ast::UseTree, rhs: &ast::UseTree, merge: MergeBehavior)
// same as a `filter` op).
.map(|tree| merge.is_tree_allowed(&tree).then_some(tree))
.collect::<Option<_>>()?;
// Preserves some positional formatting info before sorting.
let positional_formatting_map: FxHashMap<_, _> = use_trees
.iter()
.enumerate()
.filter_map(|(idx, tree)| {
formatting_whitespace(&SyntaxElement::from(tree.syntax().clone()))
.map(|trivia| (idx, trivia))
})
.collect();
let closing_formatting_trivia = if use_trees.len() > 0 {
lhs.use_tree_list()
.and_then(|list| list.r_curly_token())
.and_then(|token| formatting_whitespace(&SyntaxElement::from(token)))
} else {
None
};
// Sorts the use trees similar to rustfmt's algorithm for ordering imports
// (see `use_tree_cmp` doc).
use_trees.sort_unstable_by(|a, b| use_tree_cmp(a, b));
@ -184,60 +168,59 @@ fn recursive_merge(lhs: &ast::UseTree, rhs: &ast::UseTree, merge: MergeBehavior)
// Creates a new use tree list with the item.
None => lhs.get_or_create_use_tree_list().add_use_tree(rhs_t),
// Recreates the use tree list with sorted items (see `use_tree_cmp` doc).
// Also attempts to preserve formatting (but only in terms of index-based
// "positions" of new lines and indents).
Some(old_list) => {
ted::remove(old_list.syntax());
Some(use_tree_list) => {
if use_tree_list.l_curly_token().is_none() {
ted::insert_raw(
Position::first_child_of(use_tree_list.syntax()),
make::token(T!['{']),
);
}
if use_tree_list.r_curly_token().is_none() {
ted::insert_raw(
Position::last_child_of(use_tree_list.syntax()),
make::token(T!['}']),
);
}
let new_list = make::use_tree_list(empty()).clone_for_update();
let mut elements = Vec::new();
for (idx, tree) in use_trees.iter().enumerate() {
if idx > 0 {
elements.push(make::token(T![,]).into());
}
match positional_formatting_map.get(&idx) {
None if idx > 0 => {
elements.push(make::tokens::single_space().into())
}
Some(prev_trivia) => {
elements.extend(prev_trivia.clone().into_iter())
}
_ => (),
elements.push(make::tokens::single_space().into());
}
elements.push(tree.syntax().clone().into());
}
if let Some(ref trivia) = closing_formatting_trivia {
elements.extend(trivia.clone().into_iter())
}
let trees_pos = match new_list.l_curly_token() {
let start = use_tree_list
.l_curly_token()
.and_then(|l_curly| {
algo::non_trivia_sibling(l_curly.into(), Direction::Next)
})
.filter(|it| it.kind() != T!['}']);
let end = use_tree_list
.r_curly_token()
.and_then(|r_curly| {
algo::non_trivia_sibling(r_curly.into(), Direction::Prev)
})
.filter(|it| it.kind() != T!['{']);
if let Some((start, end)) = start.zip(end) {
// Attempt to insert elements while preserving preceding and trailing trivia.
ted::replace_all(start..=end, elements);
} else {
let new_use_tree_list = make::use_tree_list(empty()).clone_for_update();
let trees_pos = match new_use_tree_list.l_curly_token() {
Some(l_curly) => Position::after(l_curly),
None => Position::last_child_of(new_list.syntax()),
None => Position::last_child_of(new_use_tree_list.syntax()),
};
ted::insert_all_raw(trees_pos, elements);
let list_pos = Position::last_child_of(lhs.syntax());
ted::insert_raw(list_pos, new_list.syntax());
ted::replace(use_tree_list.syntax(), new_use_tree_list.syntax());
}
}
}
}
}
return Some(());
// Returns all trivia preceding a syntax element if it may be relevant to formatting
// (i.e. includes at least one new line character).
fn formatting_whitespace(elem: &SyntaxElement) -> Option<FxHashSet<SyntaxElement>> {
let succ =
|item: &SyntaxElement| item.prev_sibling_or_token().filter(|it| it.kind().is_trivia());
let first = succ(elem);
let trivia_set: FxHashSet<_> = successors(first, succ).collect();
let contains_formatting_whitespace = trivia_set.iter().any(|it| {
it.kind() == SyntaxKind::WHITESPACE
&& it.as_token().is_some_and(|token| token.text().contains('\n'))
});
contains_formatting_whitespace.then_some(trivia_set)
}
Some(())
}
/// Traverses both paths until they differ, returning the common prefix of both.
@ -383,13 +366,13 @@ fn path_segment_cmp(a: &ast::PathSegment, b: &ast::PathSegment) -> Ordering {
}
}
// Orders for use trees with equal paths (see `use_tree_cmp` for details about use tree ordering).
//
// If the `strict` parameter is set to true and both trees have tree lists, the tree lists are
// ordered by calling `use_tree_cmp` on their "sub-tree" pairs until either the tie is broken
// or tree list equality is confirmed, otherwise (i.e. if either `strict` is false or at least
// one of the trees does *not* have tree list), this potentially recursive step is skipped,
// and only the presence of a glob pattern or an alias is used to determine the ordering.
/// Orders for use trees with equal paths (see `use_tree_cmp` for details about use tree ordering).
///
/// If the `strict` parameter is set to true and both trees have tree lists, the tree lists are
/// ordered by calling `use_tree_cmp` on their "sub-tree" pairs until either the tie is broken
/// or tree list equality is confirmed, otherwise (i.e. if either `strict` is false or at least
/// one of the trees does *not* have tree list), this potentially recursive step is skipped,
/// and only the presence of a glob pattern or an alias is used to determine the ordering.
fn use_tree_cmp_by_tree_list_glob_or_alias(
a: &ast::UseTree,
b: &ast::UseTree,