From ff42008679c9b09fc9865fe55eba99d7ed6a0d05 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Fri, 28 Feb 2020 21:53:20 +0100 Subject: Move insert_use util to utils --- crates/ra_assists/src/utils/insert_use.rs | 515 ++++++++++++++++++++++++++++++ 1 file changed, 515 insertions(+) create mode 100644 crates/ra_assists/src/utils/insert_use.rs (limited to 'crates/ra_assists/src/utils') diff --git a/crates/ra_assists/src/utils/insert_use.rs b/crates/ra_assists/src/utils/insert_use.rs new file mode 100644 index 000000000..7ae3440ca --- /dev/null +++ b/crates/ra_assists/src/utils/insert_use.rs @@ -0,0 +1,515 @@ +//! Handle syntactic aspects of inserting a new `use`. + +use hir::{self, ModPath}; +use ra_syntax::{ + ast::{self, NameOwner}, + AstNode, Direction, SmolStr, + SyntaxKind::{PATH, PATH_SEGMENT}, + SyntaxNode, T, +}; +use ra_text_edit::TextEditBuilder; + +/// Creates and inserts a use statement for the given path to import. +/// The use statement is inserted in the scope most appropriate to the +/// the cursor position given, additionally merged with the existing use imports. +pub fn insert_use_statement( + // Ideally the position of the cursor, used to + position: &SyntaxNode, + // The statement to use as anchor (last resort) + anchor: &SyntaxNode, + path_to_import: &ModPath, + edit: &mut TextEditBuilder, +) { + let target = path_to_import.to_string().split("::").map(SmolStr::new).collect::>(); + let container = position.ancestors().find_map(|n| { + if let Some(module) = ast::Module::cast(n.clone()) { + return module.item_list().map(|it| it.syntax().clone()); + } + ast::SourceFile::cast(n).map(|it| it.syntax().clone()) + }); + + if let Some(container) = container { + let action = best_action_for_target(container, anchor.clone(), &target); + make_assist(&action, &target, edit); + } +} + +fn collect_path_segments_raw( + segments: &mut Vec, + mut path: ast::Path, +) -> Option { + let oldlen = segments.len(); + loop { + let mut children = path.syntax().children_with_tokens(); + let (first, second, third) = ( + children.next().map(|n| (n.clone(), n.kind())), + children.next().map(|n| (n.clone(), n.kind())), + children.next().map(|n| (n.clone(), n.kind())), + ); + match (first, second, third) { + (Some((subpath, PATH)), Some((_, T![::])), Some((segment, PATH_SEGMENT))) => { + path = ast::Path::cast(subpath.as_node()?.clone())?; + segments.push(ast::PathSegment::cast(segment.as_node()?.clone())?); + } + (Some((segment, PATH_SEGMENT)), _, _) => { + segments.push(ast::PathSegment::cast(segment.as_node()?.clone())?); + break; + } + (_, _, _) => return None, + } + } + // We need to reverse only the new added segments + let only_new_segments = segments.split_at_mut(oldlen).1; + only_new_segments.reverse(); + Some(segments.len() - oldlen) +} + +fn fmt_segments_raw(segments: &[SmolStr], buf: &mut String) { + let mut iter = segments.iter(); + if let Some(s) = iter.next() { + buf.push_str(s); + } + for s in iter { + buf.push_str("::"); + buf.push_str(s); + } +} + +/// Returns the number of common segments. +fn compare_path_segments(left: &[SmolStr], right: &[ast::PathSegment]) -> usize { + left.iter().zip(right).take_while(|(l, r)| compare_path_segment(l, r)).count() +} + +fn compare_path_segment(a: &SmolStr, b: &ast::PathSegment) -> bool { + if let Some(kb) = b.kind() { + match kb { + ast::PathSegmentKind::Name(nameref_b) => a == nameref_b.text(), + ast::PathSegmentKind::SelfKw => a == "self", + ast::PathSegmentKind::SuperKw => a == "super", + ast::PathSegmentKind::CrateKw => a == "crate", + ast::PathSegmentKind::Type { .. } => false, // not allowed in imports + } + } else { + false + } +} + +fn compare_path_segment_with_name(a: &SmolStr, b: &ast::Name) -> bool { + a == b.text() +} + +#[derive(Clone, Debug)] +enum ImportAction { + Nothing, + // Add a brand new use statement. + AddNewUse { + anchor: Option, // anchor node + add_after_anchor: bool, + }, + + // To split an existing use statement creating a nested import. + AddNestedImport { + // how may segments matched with the target path + common_segments: usize, + path_to_split: ast::Path, + // the first segment of path_to_split we want to add into the new nested list + first_segment_to_split: Option, + // Wether to add 'self' in addition to the target path + add_self: bool, + }, + // To add the target path to an existing nested import tree list. + AddInTreeList { + common_segments: usize, + // The UseTreeList where to add the target path + tree_list: ast::UseTreeList, + add_self: bool, + }, +} + +impl ImportAction { + fn add_new_use(anchor: Option, add_after_anchor: bool) -> Self { + ImportAction::AddNewUse { anchor, add_after_anchor } + } + + fn add_nested_import( + common_segments: usize, + path_to_split: ast::Path, + first_segment_to_split: Option, + add_self: bool, + ) -> Self { + ImportAction::AddNestedImport { + common_segments, + path_to_split, + first_segment_to_split, + add_self, + } + } + + fn add_in_tree_list( + common_segments: usize, + tree_list: ast::UseTreeList, + add_self: bool, + ) -> Self { + ImportAction::AddInTreeList { common_segments, tree_list, add_self } + } + + fn better(left: ImportAction, right: ImportAction) -> ImportAction { + if left.is_better(&right) { + left + } else { + right + } + } + + fn is_better(&self, other: &ImportAction) -> bool { + match (self, other) { + (ImportAction::Nothing, _) => true, + (ImportAction::AddInTreeList { .. }, ImportAction::Nothing) => false, + ( + ImportAction::AddNestedImport { common_segments: n, .. }, + ImportAction::AddInTreeList { common_segments: m, .. }, + ) + | ( + ImportAction::AddInTreeList { common_segments: n, .. }, + ImportAction::AddNestedImport { common_segments: m, .. }, + ) + | ( + ImportAction::AddInTreeList { common_segments: n, .. }, + ImportAction::AddInTreeList { common_segments: m, .. }, + ) + | ( + ImportAction::AddNestedImport { common_segments: n, .. }, + ImportAction::AddNestedImport { common_segments: m, .. }, + ) => n > m, + (ImportAction::AddInTreeList { .. }, _) => true, + (ImportAction::AddNestedImport { .. }, ImportAction::Nothing) => false, + (ImportAction::AddNestedImport { .. }, _) => true, + (ImportAction::AddNewUse { .. }, _) => false, + } + } +} + +// Find out the best ImportAction to import target path against current_use_tree. +// If current_use_tree has a nested import the function gets called recursively on every UseTree inside a UseTreeList. +fn walk_use_tree_for_best_action( + current_path_segments: &mut Vec, // buffer containing path segments + current_parent_use_tree_list: Option, // will be Some value if we are in a nested import + current_use_tree: ast::UseTree, // the use tree we are currently examinating + target: &[SmolStr], // the path we want to import +) -> ImportAction { + // We save the number of segments in the buffer so we can restore the correct segments + // before returning. Recursive call will add segments so we need to delete them. + let prev_len = current_path_segments.len(); + + let tree_list = current_use_tree.use_tree_list(); + let alias = current_use_tree.alias(); + + let path = match current_use_tree.path() { + Some(path) => path, + None => { + // If the use item don't have a path, it means it's broken (syntax error) + return ImportAction::add_new_use( + current_use_tree + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .map(|it| it.syntax().clone()), + true, + ); + } + }; + + // This can happen only if current_use_tree is a direct child of a UseItem + if let Some(name) = alias.and_then(|it| it.name()) { + if compare_path_segment_with_name(&target[0], &name) { + return ImportAction::Nothing; + } + } + + collect_path_segments_raw(current_path_segments, path.clone()); + + // We compare only the new segments added in the line just above. + // The first prev_len segments were already compared in 'parent' recursive calls. + let left = target.split_at(prev_len).1; + let right = current_path_segments.split_at(prev_len).1; + let common = compare_path_segments(left, &right); + let mut action = match common { + 0 => ImportAction::add_new_use( + // e.g: target is std::fmt and we can have + // use foo::bar + // We add a brand new use statement + current_use_tree + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .map(|it| it.syntax().clone()), + true, + ), + common if common == left.len() && left.len() == right.len() => { + // e.g: target is std::fmt and we can have + // 1- use std::fmt; + // 2- use std::fmt::{ ... } + if let Some(list) = tree_list { + // In case 2 we need to add self to the nested list + // unless it's already there + let has_self = list.use_trees().map(|it| it.path()).any(|p| { + p.and_then(|it| it.segment()) + .and_then(|it| it.kind()) + .filter(|k| *k == ast::PathSegmentKind::SelfKw) + .is_some() + }); + + if has_self { + ImportAction::Nothing + } else { + ImportAction::add_in_tree_list(current_path_segments.len(), list, true) + } + } else { + // Case 1 + ImportAction::Nothing + } + } + common if common != left.len() && left.len() == right.len() => { + // e.g: target is std::fmt and we have + // use std::io; + // We need to split. + let segments_to_split = current_path_segments.split_at(prev_len + common).1; + ImportAction::add_nested_import( + prev_len + common, + path, + Some(segments_to_split[0].clone()), + false, + ) + } + common if common == right.len() && left.len() > right.len() => { + // e.g: target is std::fmt and we can have + // 1- use std; + // 2- use std::{ ... }; + + // fallback action + let mut better_action = ImportAction::add_new_use( + current_use_tree + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .map(|it| it.syntax().clone()), + true, + ); + if let Some(list) = tree_list { + // Case 2, check recursively if the path is already imported in the nested list + for u in list.use_trees() { + let child_action = walk_use_tree_for_best_action( + current_path_segments, + Some(list.clone()), + u, + target, + ); + if child_action.is_better(&better_action) { + better_action = child_action; + if let ImportAction::Nothing = better_action { + return better_action; + } + } + } + } else { + // Case 1, split adding self + better_action = ImportAction::add_nested_import(prev_len + common, path, None, true) + } + better_action + } + common if common == left.len() && left.len() < right.len() => { + // e.g: target is std::fmt and we can have + // use std::fmt::Debug; + let segments_to_split = current_path_segments.split_at(prev_len + common).1; + ImportAction::add_nested_import( + prev_len + common, + path, + Some(segments_to_split[0].clone()), + true, + ) + } + common if common < left.len() && common < right.len() => { + // e.g: target is std::fmt::nested::Debug + // use std::fmt::Display + let segments_to_split = current_path_segments.split_at(prev_len + common).1; + ImportAction::add_nested_import( + prev_len + common, + path, + Some(segments_to_split[0].clone()), + false, + ) + } + _ => unreachable!(), + }; + + // If we are inside a UseTreeList adding a use statement become adding to the existing + // tree list. + action = match (current_parent_use_tree_list, action.clone()) { + (Some(use_tree_list), ImportAction::AddNewUse { .. }) => { + ImportAction::add_in_tree_list(prev_len, use_tree_list, false) + } + (_, _) => action, + }; + + // We remove the segments added + current_path_segments.truncate(prev_len); + action +} + +fn best_action_for_target( + container: SyntaxNode, + anchor: SyntaxNode, + target: &[SmolStr], +) -> ImportAction { + let mut storage = Vec::with_capacity(16); // this should be the only allocation + let best_action = container + .children() + .filter_map(ast::UseItem::cast) + .filter_map(|it| it.use_tree()) + .map(|u| walk_use_tree_for_best_action(&mut storage, None, u, target)) + .fold(None, |best, a| match best { + Some(best) => Some(ImportAction::better(best, a)), + None => Some(a), + }); + + match best_action { + Some(action) => action, + None => { + // We have no action and no UseItem was found in container so we find + // another item and we use it as anchor. + // If there are no items above, we choose the target path itself as anchor. + // todo: we should include even whitespace blocks as anchor candidates + let anchor = container + .children() + .find(|n| n.text_range().start() < anchor.text_range().start()) + .or_else(|| Some(anchor)); + + let add_after_anchor = anchor + .clone() + .and_then(ast::Attr::cast) + .map(|attr| attr.kind() == ast::AttrKind::Inner) + .unwrap_or(false); + ImportAction::add_new_use(anchor, add_after_anchor) + } + } +} + +fn make_assist(action: &ImportAction, target: &[SmolStr], edit: &mut TextEditBuilder) { + match action { + ImportAction::AddNewUse { anchor, add_after_anchor } => { + make_assist_add_new_use(anchor, *add_after_anchor, target, edit) + } + ImportAction::AddInTreeList { common_segments, tree_list, add_self } => { + // We know that the fist n segments already exists in the use statement we want + // to modify, so we want to add only the last target.len() - n segments. + let segments_to_add = target.split_at(*common_segments).1; + make_assist_add_in_tree_list(tree_list, segments_to_add, *add_self, edit) + } + ImportAction::AddNestedImport { + common_segments, + path_to_split, + first_segment_to_split, + add_self, + } => { + let segments_to_add = target.split_at(*common_segments).1; + make_assist_add_nested_import( + path_to_split, + first_segment_to_split, + segments_to_add, + *add_self, + edit, + ) + } + _ => {} + } +} + +fn make_assist_add_new_use( + anchor: &Option, + after: bool, + target: &[SmolStr], + edit: &mut TextEditBuilder, +) { + if let Some(anchor) = anchor { + let indent = ra_fmt::leading_indent(anchor); + let mut buf = String::new(); + if after { + buf.push_str("\n"); + if let Some(spaces) = &indent { + buf.push_str(spaces); + } + } + buf.push_str("use "); + fmt_segments_raw(target, &mut buf); + buf.push_str(";"); + if !after { + buf.push_str("\n\n"); + if let Some(spaces) = &indent { + buf.push_str(&spaces); + } + } + let position = if after { anchor.text_range().end() } else { anchor.text_range().start() }; + edit.insert(position, buf); + } +} + +fn make_assist_add_in_tree_list( + tree_list: &ast::UseTreeList, + target: &[SmolStr], + add_self: bool, + edit: &mut TextEditBuilder, +) { + let last = tree_list.use_trees().last(); + if let Some(last) = last { + let mut buf = String::new(); + let comma = last.syntax().siblings(Direction::Next).find(|n| n.kind() == T![,]); + let offset = if let Some(comma) = comma { + comma.text_range().end() + } else { + buf.push_str(","); + last.syntax().text_range().end() + }; + if add_self { + buf.push_str(" self") + } else { + buf.push_str(" "); + } + fmt_segments_raw(target, &mut buf); + edit.insert(offset, buf); + } else { + } +} + +fn make_assist_add_nested_import( + path: &ast::Path, + first_segment_to_split: &Option, + target: &[SmolStr], + add_self: bool, + edit: &mut TextEditBuilder, +) { + let use_tree = path.syntax().ancestors().find_map(ast::UseTree::cast); + if let Some(use_tree) = use_tree { + let (start, add_colon_colon) = if let Some(first_segment_to_split) = first_segment_to_split + { + (first_segment_to_split.syntax().text_range().start(), false) + } else { + (use_tree.syntax().text_range().end(), true) + }; + let end = use_tree.syntax().text_range().end(); + + let mut buf = String::new(); + if add_colon_colon { + buf.push_str("::"); + } + buf.push_str("{"); + if add_self { + buf.push_str("self, "); + } + fmt_segments_raw(target, &mut buf); + if !target.is_empty() { + buf.push_str(", "); + } + edit.insert(start, buf); + edit.insert(end, "}".to_string()); + } +} -- cgit v1.2.3