diff --git a/Cargo.lock b/Cargo.lock index 9c65b39f761..40621e89164 100644 --- a/Cargo.lock +++ b/Cargo.lock @@ -900,6 +900,7 @@ version = "0.1.0" name = "ra_assists" version = "0.1.0" dependencies = [ + "itertools 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)", "join_to_string 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)", "ra_db 0.1.0", "ra_fmt 0.1.0", diff --git a/crates/ra_assists/Cargo.toml b/crates/ra_assists/Cargo.toml index 71ab2dcd2a0..a5808d5b7f2 100644 --- a/crates/ra_assists/Cargo.toml +++ b/crates/ra_assists/Cargo.toml @@ -6,6 +6,7 @@ authors = ["Aleksey Kladov "] [dependencies] join_to_string = "0.1.3" +itertools = "0.8.0" ra_syntax = { path = "../ra_syntax" } ra_text_edit = { path = "../ra_text_edit" } diff --git a/crates/ra_assists/src/auto_import.rs b/crates/ra_assists/src/auto_import.rs new file mode 100644 index 00000000000..4cac5a92640 --- /dev/null +++ b/crates/ra_assists/src/auto_import.rs @@ -0,0 +1,780 @@ +use hir::db::HirDatabase; +use ra_syntax::{ + ast, AstNode, SyntaxNode, Direction, TextRange, + SyntaxKind::{ PATH, PATH_SEGMENT, COLONCOLON, COMMA } +}; +use crate::assist_ctx::{AssistCtx, Assist, AssistBuilder}; +use itertools::{ Itertools, EitherOrBoth }; + +// TODO: refactor this before merge +mod formatting { + use ra_syntax::{ + AstNode, SyntaxNode, + ast::{self, AstToken}, + algo::generate, +}; + + /// If the node is on the beginning of the line, calculate indent. + pub fn leading_indent(node: &SyntaxNode) -> Option<&str> { + for leaf in prev_leaves(node) { + if let Some(ws) = ast::Whitespace::cast(leaf) { + let ws_text = ws.text(); + if let Some(pos) = ws_text.rfind('\n') { + return Some(&ws_text[pos + 1..]); + } + } + if leaf.leaf_text().unwrap().contains('\n') { + break; + } + } + None + } + + fn prev_leaves(node: &SyntaxNode) -> impl Iterator { + generate(prev_leaf(node), |&node| prev_leaf(node)) + } + + fn prev_leaf(node: &SyntaxNode) -> Option<&SyntaxNode> { + generate(node.ancestors().find_map(SyntaxNode::prev_sibling), |it| { + it.last_child() + }) + .last() + } +} + +fn collect_path_segments(path: &ast::Path) -> Option> { + let mut v = Vec::new(); + collect_path_segments_raw(&mut v, path)?; + return Some(v); +} + +fn collect_path_segments_raw<'b, 'a: 'b>( + segments: &'b mut Vec<&'a ast::PathSegment>, + mut path: &'a ast::Path, +) -> Option { + let oldlen = segments.len(); + loop { + let mut children = path.syntax().children(); + let (first, second, third) = ( + children.next().map(|n| (n, n.kind())), + children.next().map(|n| (n, n.kind())), + children.next().map(|n| (n, n.kind())), + ); + match (first, second, third) { + (Some((subpath, PATH)), Some((_, COLONCOLON)), Some((segment, PATH_SEGMENT))) => { + path = ast::Path::cast(subpath)?; + segments.push(ast::PathSegment::cast(segment)?); + } + (Some((segment, PATH_SEGMENT)), _, _) => { + segments.push(ast::PathSegment::cast(segment)?); + 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(); + return Some(segments.len() - oldlen); +} + +fn fmt_segments(segments: &[&ast::PathSegment]) -> String { + let mut buf = String::new(); + fmt_segments_raw(segments, &mut buf); + return buf; +} + +fn fmt_segments_raw(segments: &[&ast::PathSegment], buf: &mut String) { + let mut first = true; + for s in segments { + if !first { + buf.push_str("::"); + } + match s.kind() { + Some(ast::PathSegmentKind::Name(nameref)) => buf.push_str(nameref.text()), + Some(ast::PathSegmentKind::SelfKw) => buf.push_str("self"), + Some(ast::PathSegmentKind::SuperKw) => buf.push_str("super"), + Some(ast::PathSegmentKind::CrateKw) => buf.push_str("crate"), + None => {} + } + first = false; + } +} + +#[derive(Copy, Clone)] +enum PathSegmentsMatch { + // Patch matches exactly + Full, + // None of the segments matched. It's a more explicit Partial(0) + Empty, + // When some of the segments matched + Partial(usize), + // When all the segments of the right path are matched against the left path, + // but the left path is longer. + PartialLeft(usize), + // When all the segments of the left path are matched against the right path, + // but the right path is longer. + PartialRight(usize), + // In all the three cases above we keep track of how many segments matched +} + +fn compare_path_segments( + left: &[&ast::PathSegment], + right: &[&ast::PathSegment], +) -> PathSegmentsMatch { + let mut matching = 0; + for either_or_both in left.iter().zip_longest(right.iter()) { + match either_or_both { + EitherOrBoth::Both(left, right) => { + if compare_path_segment(left, right) { + matching += 1 + } else { + return if matching == 0 { + PathSegmentsMatch::Empty + } else { + PathSegmentsMatch::Partial(matching) + }; + } + } + EitherOrBoth::Left(_) => { + return PathSegmentsMatch::PartialLeft(matching); + } + EitherOrBoth::Right(_) => { + return PathSegmentsMatch::PartialRight(matching); + } + } + } + return PathSegmentsMatch::Full; +} + +fn compare_path_segment(a: &ast::PathSegment, b: &ast::PathSegment) -> bool { + if let (Some(ka), Some(kb)) = (a.kind(), b.kind()) { + return match (ka, kb) { + (ast::PathSegmentKind::Name(nameref_a), ast::PathSegmentKind::Name(nameref_b)) => { + nameref_a.text() == nameref_b.text() + } + (ast::PathSegmentKind::SelfKw, ast::PathSegmentKind::SelfKw) => true, + (ast::PathSegmentKind::SuperKw, ast::PathSegmentKind::SuperKw) => true, + (ast::PathSegmentKind::CrateKw, ast::PathSegmentKind::CrateKw) => true, + (_, _) => false, + }; + } else { + false + } +} + +fn compare_path_segment_with_name(a: &ast::PathSegment, b: &ast::Name) -> bool { + if let Some(ka) = a.kind() { + return match (ka, b) { + (ast::PathSegmentKind::Name(nameref_a), _) => nameref_a.text() == b.text(), + (_, _) => false, + }; + } else { + false + } +} + +#[derive(Copy, Clone)] +enum ImportAction<'a> { + Nothing, + // Add a brand new use statement. + AddNewUse( + Option<&'a SyntaxNode>, // anchor node + bool, // true if we want to add the new statement after the anchor + ), + + // In the following actions we keep track of how may segments matched, + // so we can choose the best action to take. + + // To split an existing use statement creating a nested import. + AddNestedImport( + usize, + &'a ast::Path, // the complete path we want to split + Option<&'a ast::PathSegment>, // the first segment of path we want to add into the new nested list + bool, // true if we want to add 'self' in addition to the segment + ), + // To add the target path to an existing nested import tree list. + AddInTreeList( + usize, + &'a ast::UseTreeList, + bool, // true if we want to add 'self' + ), +} + +impl<'a> ImportAction<'a> { + fn better<'b>(left: &'b ImportAction<'a>, right: &'b ImportAction<'a>) -> &'b ImportAction<'a> { + 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(n, ..), ImportAction::AddInTreeList(m, ..)) => n > m, + (ImportAction::AddInTreeList(n, ..), ImportAction::AddNestedImport(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<'b, 'c, 'a: 'b + 'c>( + current_path_segments: &'b mut Vec<&'a ast::PathSegment>, // buffer containing path segments + current_parent_use_tree_list: Option<&'a ast::UseTreeList>, // will be Some value if we are in a nested import + current_use_tree: &'a ast::UseTree, // the use tree we are currently examinating + target: &'c [&'a ast::PathSegment], // the path we want to import +) -> ImportAction<'a> { + // 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::AddNewUse( + current_use_tree + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .map(AstNode::syntax), + true, + ); + } + }; + + // This can happen only if current_use_tree is a direct child of a UseItem + if let Some(name) = alias.and_then(ast::NameOwner::name) { + if compare_path_segment_with_name(target[0], name) { + return ImportAction::Nothing; + } + } + + collect_path_segments_raw(current_path_segments, path); + + // 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 c = compare_path_segments( + target.split_at(prev_len).1, + current_path_segments.split_at(prev_len).1, + ); + + let mut action = match c { + PathSegmentsMatch::Full => { + // 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(ast::UseTree::path).any(|p| { + p.and_then(ast::Path::segment) + .and_then(ast::PathSegment::kind) + .filter(|k| *k == ast::PathSegmentKind::SelfKw) + .is_some() + }); + + if has_self { + ImportAction::Nothing + } else { + ImportAction::AddInTreeList(current_path_segments.len(), list, true) + } + } else { + // Case 1 + ImportAction::Nothing + } + } + PathSegmentsMatch::Empty => ImportAction::AddNewUse( + // 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(AstNode::syntax), + true, + ), + PathSegmentsMatch::Partial(n) => { + // 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 + n).1; + ImportAction::AddNestedImport(prev_len + n, path, Some(segments_to_split[0]), false) + } + PathSegmentsMatch::PartialLeft(n) => { + // e.g: target is std::fmt and we can have + // 1- use std; + // 2- use std::{ ... }; + + // fallback action + let mut better_action = ImportAction::AddNewUse( + current_use_tree + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .map(AstNode::syntax), + 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), 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 + better_action = ImportAction::AddNestedImport(prev_len + n, path, None, true) + } + better_action + } + PathSegmentsMatch::PartialRight(n) => { + // e.g: target std::fmt and we can have + // use std::fmt::Debug; + let segments_to_split = current_path_segments.split_at(prev_len + n).1; + ImportAction::AddNestedImport(prev_len + n, path, Some(segments_to_split[0]), true) + } + }; + + // 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) { + (Some(use_tree_list), ImportAction::AddNewUse(..)) => { + ImportAction::AddInTreeList(prev_len, use_tree_list, false) + } + (_, _) => action, + }; + + // We remove the segments added + current_path_segments.truncate(prev_len); + return action; +} + +fn best_action_for_target<'b, 'a: 'b>( + container: &'a SyntaxNode, + path: &'a ast::Path, + target: &'b [&'a ast::PathSegment], +) -> ImportAction<'a> { + 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(ast::UseItem::use_tree) + .map(|u| walk_use_tree_for_best_action(&mut storage, None, u, target)) + .fold(None, |best, a| { + best.and_then(|best| Some(*ImportAction::better(&best, &a))) + .or(Some(a)) + }); + + match best_action { + Some(action) => return action, + None => { + // We have no action we no use item was found in container so we find + // another item and we use it as anchor. + // If there are not items, we choose the target path itself as anchor. + let anchor = container + .children() + .find_map(ast::ModuleItem::cast) + .map(AstNode::syntax) + .or(Some(path.syntax())); + + return ImportAction::AddNewUse(anchor, false); + } + } +} + +fn make_assist(action: &ImportAction, target: &[&ast::PathSegment], edit: &mut AssistBuilder) { + match action { + ImportAction::AddNewUse(anchor, after) => { + make_assist_add_new_use(anchor, *after, target, edit) + } + ImportAction::AddInTreeList(n, tree_list_node, 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(*n).1; + make_assist_add_in_tree_list(tree_list_node, segments_to_add, *add_self, edit) + } + ImportAction::AddNestedImport(n, path, first_segment_to_split, add_self) => { + let segments_to_add = target.split_at(*n).1; + make_assist_add_nested_import( + path, + first_segment_to_split, + segments_to_add, + *add_self, + edit, + ) + } + _ => {} + } +} + +fn make_assist_add_new_use( + anchor: &Option<&SyntaxNode>, + after: bool, + target: &[&ast::PathSegment], + edit: &mut AssistBuilder, +) { + if let Some(anchor) = anchor { + let indent = formatting::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.range().end() + } else { + anchor.range().start() + }; + edit.insert(position, buf); + } +} + +fn make_assist_add_in_tree_list( + tree_list: &ast::UseTreeList, + target: &[&ast::PathSegment], + add_self: bool, + edit: &mut AssistBuilder, +) { + 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() == COMMA); + let offset = if let Some(comma) = comma { + comma.range().end() + } else { + buf.push_str(","); + last.syntax().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<&ast::PathSegment>, + target: &[&ast::PathSegment], + add_self: bool, + edit: &mut AssistBuilder, +) { + 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().range().start(), false) + } else { + (use_tree.syntax().range().end(), true) + }; + let end = use_tree.syntax().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, "}"); + } +} + +pub(crate) fn auto_import(ctx: AssistCtx) -> Option { + let node = ctx.covering_node(); + let current_file = node.ancestors().find_map(ast::SourceFile::cast)?; + + let path = node.ancestors().find_map(ast::Path::cast)?; + // We don't want to mess with use statements + if path + .syntax() + .ancestors() + .find_map(ast::UseItem::cast) + .is_some() + { + return None; + } + + let segments = collect_path_segments(path)?; + if segments.len() < 2 { + return None; + } + + ctx.build( + format!("import {} in the current file", fmt_segments(&segments)), + |edit| { + let action = best_action_for_target(current_file.syntax(), path, &segments); + make_assist(&action, segments.as_slice(), edit); + if let Some(last_segment) = path.segment() { + // Here we are assuming the assist will provide a correct use statement + // so we can delete the path qualifier + edit.delete(TextRange::from_to( + path.syntax().range().start(), + last_segment.syntax().range().start(), + )); + } + }, + ) +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::helpers::{ check_assist, check_assist_not_applicable }; + + #[test] + fn test_auto_import_file_add_use_no_anchor() { + check_assist( + auto_import, + " +std::fmt::Debug<|> + ", + " +use std::fmt::Debug; + +Debug<|> + ", + ); + } + + #[test] + fn test_auto_import_file_add_use() { + check_assist( + auto_import, + " +use stdx; + +impl std::fmt::Debug<|> for Foo { +} + ", + " +use stdx; +use std::fmt::Debug; + +impl Debug<|> for Foo { +} + ", + ); + } + + #[test] + fn test_auto_import_file_add_use_other_anchor() { + check_assist( + auto_import, + " +impl std::fmt::Debug<|> for Foo { +} + ", + " +use std::fmt::Debug; + +impl Debug<|> for Foo { +} + ", + ); + } + + #[test] + fn test_auto_import_file_add_use_other_anchor_indent() { + check_assist( + auto_import, + " + impl std::fmt::Debug<|> for Foo { + } + ", + " + use std::fmt::Debug; + + impl Debug<|> for Foo { + } + ", + ); + } + + #[test] + fn test_auto_import_file_split_different() { + check_assist( + auto_import, + " +use std::fmt; + +impl std::io<|> for Foo { +} + ", + " +use std::{ io, fmt}; + +impl io<|> for Foo { +} + ", + ); + } + + #[test] + fn test_auto_import_file_split_self_for_use() { + check_assist( + auto_import, + " +use std::fmt; + +impl std::fmt::Debug<|> for Foo { +} + ", + " +use std::fmt::{ self, Debug, }; + +impl Debug<|> for Foo { +} + ", + ); + } + + #[test] + fn test_auto_import_file_split_self_for_target() { + check_assist( + auto_import, + " +use std::fmt::Debug; + +impl std::fmt<|> for Foo { +} + ", + " +use std::fmt::{ self, Debug}; + +impl fmt<|> for Foo { +} + ", + ); + } + + #[test] + fn test_auto_import_file_add_to_nested_self_nested() { + check_assist( + auto_import, + " +use std::fmt::{Debug, nested::{Display}}; + +impl std::fmt::nested<|> for Foo { +} +", + " +use std::fmt::{Debug, nested::{Display, self}}; + +impl nested<|> for Foo { +} +", + ); + } + + #[test] + fn test_auto_import_file_add_to_nested_self_already_included() { + check_assist( + auto_import, + " +use std::fmt::{Debug, nested::{self, Display}}; + +impl std::fmt::nested<|> for Foo { +} +", + " +use std::fmt::{Debug, nested::{self, Display}}; + +impl nested<|> for Foo { +} +", + ); + } + + #[test] + fn test_auto_import_file_add_to_nested_nested() { + check_assist( + auto_import, + " +use std::fmt::{Debug, nested::{Display}}; + +impl std::fmt::nested::Debug<|> for Foo { +} +", + " +use std::fmt::{Debug, nested::{Display, Debug}}; + +impl Debug<|> for Foo { +} +", + ); + } + + #[test] + fn test_auto_import_file_alias() { + check_assist( + auto_import, + " +use std::fmt as foo; + +impl foo::Debug<|> for Foo { +} +", + " +use std::fmt as foo; + +impl Debug<|> for Foo { +} +", + ); + } + + #[test] + fn test_auto_import_not_applicable_one_segment() { + check_assist_not_applicable( + auto_import, + " +impl foo<|> for Foo { +} +", + ); + } +} diff --git a/crates/ra_assists/src/lib.rs b/crates/ra_assists/src/lib.rs index 7928b49830b..af578893efc 100644 --- a/crates/ra_assists/src/lib.rs +++ b/crates/ra_assists/src/lib.rs @@ -84,6 +84,8 @@ mod introduce_variable; mod replace_if_let_with_match; mod split_import; mod remove_dbg; +mod auto_import; + fn all_assists() -> &'static [fn(AssistCtx) -> Option] { &[ add_derive::add_derive, @@ -95,6 +97,7 @@ fn all_assists() -> &'static [fn(AssistCtx) -> Option