Unnamed repository; edit this file 'description' to name the repository.
| -rw-r--r-- | crates/syntax/src/lib.rs | 1 | ||||
| -rw-r--r-- | crates/syntax/src/syntax_editor.rs | 611 | ||||
| -rw-r--r-- | crates/syntax/src/syntax_editor/edit_algo.rs | 367 | ||||
| -rw-r--r-- | crates/syntax/src/syntax_editor/mapping.rs | 272 |
4 files changed, 1251 insertions, 0 deletions
diff --git a/crates/syntax/src/lib.rs b/crates/syntax/src/lib.rs index b68374848b..dbbb290b4f 100644 --- a/crates/syntax/src/lib.rs +++ b/crates/syntax/src/lib.rs @@ -40,6 +40,7 @@ pub mod ast; #[doc(hidden)] pub mod fuzz; pub mod hacks; +pub mod syntax_editor; pub mod ted; pub mod utils; diff --git a/crates/syntax/src/syntax_editor.rs b/crates/syntax/src/syntax_editor.rs new file mode 100644 index 0000000000..eb114f5e5f --- /dev/null +++ b/crates/syntax/src/syntax_editor.rs @@ -0,0 +1,611 @@ +//! Syntax Tree editor +//! +//! Inspired by Roslyn's [`SyntaxEditor`], but is temporarily built upon mutable syntax tree editing. +//! +//! [`SyntaxEditor`]: https://github.com/dotnet/roslyn/blob/43b0b05cc4f492fd5de00f6f6717409091df8daa/src/Workspaces/Core/Portable/Editing/SyntaxEditor.cs + +use std::{ + num::NonZeroU32, + ops::RangeInclusive, + sync::atomic::{AtomicU32, Ordering}, +}; + +use rowan::TextRange; +use rustc_hash::FxHashMap; + +use crate::{SyntaxElement, SyntaxNode, SyntaxToken}; + +mod edit_algo; +mod mapping; + +pub use mapping::{SyntaxMapping, SyntaxMappingBuilder}; + +#[derive(Debug)] +pub struct SyntaxEditor { + root: SyntaxNode, + changes: Vec<Change>, + mappings: SyntaxMapping, + annotations: Vec<(SyntaxElement, SyntaxAnnotation)>, +} + +impl SyntaxEditor { + /// Creates a syntax editor to start editing from `root` + pub fn new(root: SyntaxNode) -> Self { + Self { root, changes: vec![], mappings: SyntaxMapping::new(), annotations: vec![] } + } + + pub fn add_annotation(&mut self, element: impl Element, annotation: SyntaxAnnotation) { + self.annotations.push((element.syntax_element(), annotation)) + } + + pub fn merge(&mut self, mut other: SyntaxEditor) { + debug_assert!( + self.root == other.root || other.root.ancestors().any(|node| node == self.root), + "{:?} is not in the same tree as {:?}", + other.root, + self.root + ); + + self.changes.append(&mut other.changes); + self.mappings.merge(other.mappings); + self.annotations.append(&mut other.annotations); + } + + pub fn insert(&mut self, position: Position, element: impl Element) { + debug_assert!(is_ancestor_or_self(&position.parent(), &self.root)); + self.changes.push(Change::Insert(position, element.syntax_element())) + } + + pub fn insert_all(&mut self, position: Position, elements: Vec<SyntaxElement>) { + debug_assert!(is_ancestor_or_self(&position.parent(), &self.root)); + self.changes.push(Change::InsertAll(position, elements)) + } + + pub fn delete(&mut self, element: impl Element) { + let element = element.syntax_element(); + debug_assert!(is_ancestor_or_self_of_element(&element, &self.root)); + debug_assert!( + !matches!(&element, SyntaxElement::Node(node) if node == &self.root), + "should not delete root node" + ); + self.changes.push(Change::Replace(element.syntax_element(), None)); + } + + pub fn replace(&mut self, old: impl Element, new: impl Element) { + let old = old.syntax_element(); + debug_assert!(is_ancestor_or_self_of_element(&old, &self.root)); + self.changes.push(Change::Replace(old.syntax_element(), Some(new.syntax_element()))); + } + + pub fn replace_with_many(&mut self, old: impl Element, new: Vec<SyntaxElement>) { + let old = old.syntax_element(); + debug_assert!(is_ancestor_or_self_of_element(&old, &self.root)); + debug_assert!( + !(matches!(&old, SyntaxElement::Node(node) if node == &self.root) && new.len() > 1), + "cannot replace root node with many elements" + ); + self.changes.push(Change::ReplaceWithMany(old.syntax_element(), new)); + } + + pub fn replace_all(&mut self, range: RangeInclusive<SyntaxElement>, new: Vec<SyntaxElement>) { + if range.start() == range.end() { + self.replace_with_many(range.start(), new); + return; + } + + debug_assert!(is_ancestor_or_self_of_element(range.start(), &self.root)); + self.changes.push(Change::ReplaceAll(range, new)) + } + + pub fn finish(self) -> SyntaxEdit { + edit_algo::apply_edits(self) + } +} + +/// Represents a completed [`SyntaxEditor`] operation. +pub struct SyntaxEdit { + old_root: SyntaxNode, + new_root: SyntaxNode, + changed_elements: Vec<SyntaxElement>, + annotations: FxHashMap<SyntaxAnnotation, Vec<SyntaxElement>>, +} + +impl SyntaxEdit { + /// Root of the initial unmodified syntax tree. + pub fn old_root(&self) -> &SyntaxNode { + &self.old_root + } + + /// Root of the modified syntax tree. + pub fn new_root(&self) -> &SyntaxNode { + &self.new_root + } + + /// Which syntax elements in the modified syntax tree were inserted or + /// modified as part of the edit. + /// + /// Note that for syntax nodes, only the upper-most parent of a set of + /// changes is included, not any child elements that may have been modified. + pub fn changed_elements(&self) -> &[SyntaxElement] { + self.changed_elements.as_slice() + } + + /// Finds which syntax elements have been annotated with the given + /// annotation. + /// + /// Note that an annotation might not appear in the modified syntax tree if + /// the syntax elements that were annotated did not make it into the final + /// syntax tree. + pub fn find_annotation(&self, annotation: SyntaxAnnotation) -> &[SyntaxElement] { + self.annotations.get(&annotation).as_ref().map_or(&[], |it| it.as_slice()) + } +} + +#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] +#[repr(transparent)] +pub struct SyntaxAnnotation(NonZeroU32); + +impl SyntaxAnnotation { + /// Creates a unique syntax annotation to attach data to. + pub fn new() -> Self { + static COUNTER: AtomicU32 = AtomicU32::new(1); + + // Only consistency within a thread matters, as SyntaxElements are !Send + let id = COUNTER.fetch_add(1, Ordering::Relaxed); + + Self(NonZeroU32::new(id).expect("syntax annotation id overflow")) + } +} + +impl Default for SyntaxAnnotation { + fn default() -> Self { + Self::new() + } +} + +/// Position describing where to insert elements +#[derive(Debug)] +pub struct Position { + repr: PositionRepr, +} + +impl Position { + pub(crate) fn parent(&self) -> SyntaxNode { + self.place().0 + } + + pub(crate) fn place(&self) -> (SyntaxNode, usize) { + match &self.repr { + PositionRepr::FirstChild(parent) => (parent.clone(), 0), + PositionRepr::After(child) => (child.parent().unwrap(), child.index() + 1), + } + } +} + +#[derive(Debug)] +enum PositionRepr { + FirstChild(SyntaxNode), + After(SyntaxElement), +} + +impl Position { + pub fn after(elem: impl Element) -> Position { + let repr = PositionRepr::After(elem.syntax_element()); + Position { repr } + } + + pub fn before(elem: impl Element) -> Position { + let elem = elem.syntax_element(); + let repr = match elem.prev_sibling_or_token() { + Some(it) => PositionRepr::After(it), + None => PositionRepr::FirstChild(elem.parent().unwrap()), + }; + Position { repr } + } + + pub fn first_child_of(node: &(impl Into<SyntaxNode> + Clone)) -> Position { + let repr = PositionRepr::FirstChild(node.clone().into()); + Position { repr } + } + + pub fn last_child_of(node: &(impl Into<SyntaxNode> + Clone)) -> Position { + let node = node.clone().into(); + let repr = match node.last_child_or_token() { + Some(it) => PositionRepr::After(it), + None => PositionRepr::FirstChild(node), + }; + Position { repr } + } +} + +#[derive(Debug)] +enum Change { + /// Inserts a single element at the specified position. + Insert(Position, SyntaxElement), + /// Inserts many elements in-order at the specified position. + InsertAll(Position, Vec<SyntaxElement>), + /// Represents both a replace single element and a delete element operation. + Replace(SyntaxElement, Option<SyntaxElement>), + /// Replaces a single element with many elements. + ReplaceWithMany(SyntaxElement, Vec<SyntaxElement>), + /// Replaces a range of elements with another list of elements. + /// Range will always have start != end. + ReplaceAll(RangeInclusive<SyntaxElement>, Vec<SyntaxElement>), +} + +impl Change { + fn target_range(&self) -> TextRange { + match self { + Change::Insert(target, _) | Change::InsertAll(target, _) => match &target.repr { + PositionRepr::FirstChild(parent) => TextRange::at( + parent.first_child_or_token().unwrap().text_range().start(), + 0.into(), + ), + PositionRepr::After(child) => TextRange::at(child.text_range().end(), 0.into()), + }, + Change::Replace(target, _) | Change::ReplaceWithMany(target, _) => target.text_range(), + Change::ReplaceAll(range, _) => { + range.start().text_range().cover(range.end().text_range()) + } + } + } + + fn target_parent(&self) -> SyntaxNode { + match self { + Change::Insert(target, _) | Change::InsertAll(target, _) => target.parent(), + Change::Replace(target, _) | Change::ReplaceWithMany(target, _) => match target { + SyntaxElement::Node(target) => target.parent().unwrap_or_else(|| target.clone()), + SyntaxElement::Token(target) => target.parent().unwrap(), + }, + Change::ReplaceAll(target, _) => target.start().parent().unwrap(), + } + } + + fn change_kind(&self) -> ChangeKind { + match self { + Change::Insert(_, _) | Change::InsertAll(_, _) => ChangeKind::Insert, + Change::Replace(_, _) | Change::ReplaceWithMany(_, _) => ChangeKind::Replace, + Change::ReplaceAll(_, _) => ChangeKind::ReplaceRange, + } + } +} + +#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] +enum ChangeKind { + Insert, + ReplaceRange, + Replace, +} + +/// Utility trait to allow calling syntax editor functions with references or owned +/// nodes. Do not use outside of this module. +pub trait Element { + fn syntax_element(self) -> SyntaxElement; +} + +impl<E: Element + Clone> Element for &'_ E { + fn syntax_element(self) -> SyntaxElement { + self.clone().syntax_element() + } +} + +impl Element for SyntaxElement { + fn syntax_element(self) -> SyntaxElement { + self + } +} + +impl Element for SyntaxNode { + fn syntax_element(self) -> SyntaxElement { + self.into() + } +} + +impl Element for SyntaxToken { + fn syntax_element(self) -> SyntaxElement { + self.into() + } +} + +fn is_ancestor_or_self(node: &SyntaxNode, ancestor: &SyntaxNode) -> bool { + node == ancestor || node.ancestors().any(|it| &it == ancestor) +} + +fn is_ancestor_or_self_of_element(node: &SyntaxElement, ancestor: &SyntaxNode) -> bool { + matches!(node, SyntaxElement::Node(node) if node == ancestor) + || node.ancestors().any(|it| &it == ancestor) +} + +#[cfg(test)] +mod tests { + use expect_test::expect; + use itertools::Itertools; + + use crate::{ + ast::{self, make, HasName}, + AstNode, + }; + + use super::*; + + fn make_ident_pat( + editor: Option<&mut SyntaxEditor>, + ref_: bool, + mut_: bool, + name: ast::Name, + ) -> ast::IdentPat { + let ast = make::ident_pat(ref_, mut_, name.clone()).clone_for_update(); + + if let Some(editor) = editor { + let mut mapping = SyntaxMappingBuilder::new(ast.syntax().clone()); + mapping.map_node(name.syntax().clone(), ast.name().unwrap().syntax().clone()); + mapping.finish(editor); + } + + ast + } + + fn make_let_stmt( + editor: Option<&mut SyntaxEditor>, + pattern: ast::Pat, + ty: Option<ast::Type>, + initializer: Option<ast::Expr>, + ) -> ast::LetStmt { + let ast = + make::let_stmt(pattern.clone(), ty.clone(), initializer.clone()).clone_for_update(); + + if let Some(editor) = editor { + let mut mapping = SyntaxMappingBuilder::new(ast.syntax().clone()); + mapping.map_node(pattern.syntax().clone(), ast.pat().unwrap().syntax().clone()); + if let Some(input) = ty { + mapping.map_node(input.syntax().clone(), ast.ty().unwrap().syntax().clone()); + } + if let Some(input) = initializer { + mapping + .map_node(input.syntax().clone(), ast.initializer().unwrap().syntax().clone()); + } + mapping.finish(editor); + } + + ast + } + + fn make_block_expr( + editor: Option<&mut SyntaxEditor>, + stmts: impl IntoIterator<Item = ast::Stmt>, + tail_expr: Option<ast::Expr>, + ) -> ast::BlockExpr { + let stmts = stmts.into_iter().collect_vec(); + let input = stmts.iter().map(|it| it.syntax().clone()).collect_vec(); + + let ast = make::block_expr(stmts, tail_expr.clone()).clone_for_update(); + + if let Some((editor, stmt_list)) = editor.zip(ast.stmt_list()) { + let mut mapping = SyntaxMappingBuilder::new(stmt_list.syntax().clone()); + + mapping.map_children( + input.into_iter(), + stmt_list.statements().map(|it| it.syntax().clone()), + ); + + if let Some((input, output)) = tail_expr.zip(stmt_list.tail_expr()) { + mapping.map_node(input.syntax().clone(), output.syntax().clone()); + } + + mapping.finish(editor); + } + + ast + } + + #[test] + fn basic_usage() { + let root = make::match_arm( + [make::wildcard_pat().into()], + None, + make::expr_tuple([ + make::expr_bin_op( + make::expr_literal("2").into(), + ast::BinaryOp::ArithOp(ast::ArithOp::Add), + make::expr_literal("2").into(), + ), + make::expr_literal("true").into(), + ]), + ); + + let to_wrap = root.syntax().descendants().find_map(ast::TupleExpr::cast).unwrap(); + let to_replace = root.syntax().descendants().find_map(ast::BinExpr::cast).unwrap(); + + let mut editor = SyntaxEditor::new(root.syntax().clone()); + + let name = make::name("var_name"); + let name_ref = make::name_ref("var_name").clone_for_update(); + + let placeholder_snippet = SyntaxAnnotation::new(); + editor.add_annotation(name.syntax(), placeholder_snippet); + editor.add_annotation(name_ref.syntax(), placeholder_snippet); + + let make_ident_pat = make_ident_pat(Some(&mut editor), false, false, name); + let make_let_stmt = make_let_stmt( + Some(&mut editor), + make_ident_pat.into(), + None, + Some(to_replace.clone().into()), + ); + let new_block = make_block_expr( + Some(&mut editor), + [make_let_stmt.into()], + Some(to_wrap.clone().into()), + ); + + editor.replace(to_replace.syntax(), name_ref.syntax()); + editor.replace(to_wrap.syntax(), new_block.syntax()); + + let edit = editor.finish(); + + let expect = expect![[r#" + _ => { + let var_name = 2 + 2; + (var_name, true) + }"#]]; + expect.assert_eq(&edit.new_root.to_string()); + + assert_eq!(edit.find_annotation(placeholder_snippet).len(), 2); + assert!(edit + .annotations + .iter() + .flat_map(|(_, elements)| elements) + .all(|element| element.ancestors().any(|it| &it == edit.new_root()))) + } + + #[test] + fn test_insert_independent() { + let root = make::block_expr( + [make::let_stmt( + make::ext::simple_ident_pat(make::name("second")).into(), + None, + Some(make::expr_literal("2").into()), + ) + .into()], + None, + ); + + let second_let = root.syntax().descendants().find_map(ast::LetStmt::cast).unwrap(); + + let mut editor = SyntaxEditor::new(root.syntax().clone()); + + editor.insert( + Position::first_child_of(root.stmt_list().unwrap().syntax()), + make_let_stmt( + None, + make::ext::simple_ident_pat(make::name("first")).into(), + None, + Some(make::expr_literal("1").into()), + ) + .syntax(), + ); + + editor.insert( + Position::after(second_let.syntax()), + make_let_stmt( + None, + make::ext::simple_ident_pat(make::name("third")).into(), + None, + Some(make::expr_literal("3").into()), + ) + .syntax(), + ); + + let edit = editor.finish(); + + let expect = expect![[r#" + let first = 1;{ + let second = 2;let third = 3; + }"#]]; + expect.assert_eq(&edit.new_root.to_string()); + } + + #[test] + fn test_insert_dependent() { + let root = make::block_expr( + [], + Some( + make::block_expr( + [make::let_stmt( + make::ext::simple_ident_pat(make::name("second")).into(), + None, + Some(make::expr_literal("2").into()), + ) + .into()], + None, + ) + .into(), + ), + ); + + let inner_block = + root.syntax().descendants().flat_map(ast::BlockExpr::cast).nth(1).unwrap(); + let second_let = root.syntax().descendants().find_map(ast::LetStmt::cast).unwrap(); + + let mut editor = SyntaxEditor::new(root.syntax().clone()); + + let new_block_expr = + make_block_expr(Some(&mut editor), [], Some(ast::Expr::BlockExpr(inner_block.clone()))); + + let first_let = make_let_stmt( + Some(&mut editor), + make::ext::simple_ident_pat(make::name("first")).into(), + None, + Some(make::expr_literal("1").into()), + ); + + let third_let = make_let_stmt( + Some(&mut editor), + make::ext::simple_ident_pat(make::name("third")).into(), + None, + Some(make::expr_literal("3").into()), + ); + + editor.insert( + Position::first_child_of(inner_block.stmt_list().unwrap().syntax()), + first_let.syntax(), + ); + editor.insert(Position::after(second_let.syntax()), third_let.syntax()); + editor.replace(inner_block.syntax(), new_block_expr.syntax()); + + let edit = editor.finish(); + + let expect = expect![[r#" + { + { + let first = 1;{ + let second = 2;let third = 3; + } + } + }"#]]; + expect.assert_eq(&edit.new_root.to_string()); + } + + #[test] + fn test_replace_root_with_dependent() { + let root = make::block_expr( + [make::let_stmt( + make::ext::simple_ident_pat(make::name("second")).into(), + None, + Some(make::expr_literal("2").into()), + ) + .into()], + None, + ); + + let inner_block = root.clone(); + + let mut editor = SyntaxEditor::new(root.syntax().clone()); + + let new_block_expr = + make_block_expr(Some(&mut editor), [], Some(ast::Expr::BlockExpr(inner_block.clone()))); + + let first_let = make_let_stmt( + Some(&mut editor), + make::ext::simple_ident_pat(make::name("first")).into(), + None, + Some(make::expr_literal("1").into()), + ); + + editor.insert( + Position::first_child_of(inner_block.stmt_list().unwrap().syntax()), + first_let.syntax(), + ); + editor.replace(inner_block.syntax(), new_block_expr.syntax()); + + let edit = editor.finish(); + + let expect = expect![[r#" + { + let first = 1;{ + let second = 2; + } + }"#]]; + expect.assert_eq(&edit.new_root.to_string()); + } +} diff --git a/crates/syntax/src/syntax_editor/edit_algo.rs b/crates/syntax/src/syntax_editor/edit_algo.rs new file mode 100644 index 0000000000..b769c94110 --- /dev/null +++ b/crates/syntax/src/syntax_editor/edit_algo.rs @@ -0,0 +1,367 @@ +//! Implementation of applying changes to a syntax tree. + +use std::{cmp::Ordering, collections::VecDeque, ops::RangeInclusive}; + +use rowan::TextRange; +use rustc_hash::FxHashMap; + +use crate::{ + syntax_editor::{mapping::MissingMapping, Change, ChangeKind, PositionRepr}, + SyntaxElement, SyntaxNode, SyntaxNodePtr, +}; + +use super::{SyntaxEdit, SyntaxEditor}; + +pub(super) fn apply_edits(editor: SyntaxEditor) -> SyntaxEdit { + // Algorithm overview: + // + // - Sort changes by (range, type) + // - Ensures that parent edits are before child edits + // - Ensures that inserts will be guaranteed to be inserted at the right range + // - Validate changes + // - Checking for invalid changes is easy since the changes will be sorted by range + // - Fixup change targets + // - standalone change? map to original syntax tree + // - dependent change? + // - try to map to parent change (either independent or another dependent) + // - note: need to keep track of a parent change stack, since a change can be a parent of multiple changes + // - Apply changes + // - find changes to apply to real tree by applying nested changes first + // - changed nodes become part of the changed node set (useful for the formatter to only change those parts) + // - Propagate annotations + + let SyntaxEditor { root, mut changes, mappings, annotations } = editor; + + let mut node_depths = FxHashMap::<SyntaxNode, usize>::default(); + let mut get_node_depth = |node: SyntaxNode| { + *node_depths.entry(node).or_insert_with_key(|node| node.ancestors().count()) + }; + + // Sort changes by range, then depth, then change kind, so that we can: + // - ensure that parent edits are ordered before child edits + // - ensure that inserts will be guaranteed to be inserted at the right range + // - easily check for disjoint replace ranges + changes.sort_by(|a, b| { + a.target_range() + .start() + .cmp(&b.target_range().start()) + .then_with(|| { + let a_target = a.target_parent(); + let b_target = b.target_parent(); + + if a_target == b_target { + return Ordering::Equal; + } + + get_node_depth(a_target).cmp(&get_node_depth(b_target)) + }) + .then(a.change_kind().cmp(&b.change_kind())) + }); + + let disjoint_replaces_ranges = changes + .iter() + .zip(changes.iter().skip(1)) + .filter(|(l, r)| { + // We only care about checking for disjoint replace ranges + matches!( + (l.change_kind(), r.change_kind()), + ( + ChangeKind::Replace | ChangeKind::ReplaceRange, + ChangeKind::Replace | ChangeKind::ReplaceRange + ) + ) + }) + .all(|(l, r)| { + get_node_depth(l.target_parent()) != get_node_depth(r.target_parent()) + || l.target_range().intersect(r.target_range()).is_none() + }); + + if stdx::never!( + !disjoint_replaces_ranges, + "some replace change ranges intersect: {:?}", + changes + ) { + return SyntaxEdit { + old_root: root.clone(), + new_root: root, + annotations: Default::default(), + changed_elements: vec![], + }; + } + + #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)] + struct DependentChange { + parent: u32, + child: u32, + } + + // Build change tree + let mut changed_ancestors: VecDeque<ChangedAncestor> = VecDeque::new(); + let mut dependent_changes = vec![]; + let mut independent_changes = vec![]; + + for (change_index, change) in changes.iter().enumerate() { + // Check if this change is dependent on another change (i.e. it's contained within another range) + if let Some(index) = changed_ancestors + .iter() + .rev() + .position(|ancestor| ancestor.affected_range().contains_range(change.target_range())) + { + // Pop off any ancestors that aren't applicable + changed_ancestors.drain((index + 1)..); + + // FIXME: Resolve changes that depend on a range of elements + let ancestor = &changed_ancestors[index]; + + dependent_changes.push(DependentChange { + parent: ancestor.change_index as u32, + child: change_index as u32, + }); + } else { + // This change is independent of any other change + + // Drain the changed ancestors since we're no longer in a set of dependent changes + changed_ancestors.drain(..); + + independent_changes.push(change_index as u32); + } + + // Add to changed ancestors, if applicable + match change { + Change::Insert(_, _) | Change::InsertAll(_, _) => {} + Change::Replace(target, _) | Change::ReplaceWithMany(target, _) => { + changed_ancestors.push_back(ChangedAncestor::single(target, change_index)) + } + Change::ReplaceAll(range, _) => { + changed_ancestors.push_back(ChangedAncestor::multiple(range, change_index)) + } + } + } + + // Map change targets to the correct syntax nodes + let tree_mutator = TreeMutator::new(&root); + let mut changed_elements = vec![]; + + for index in independent_changes { + match &mut changes[index as usize] { + Change::Insert(target, _) | Change::InsertAll(target, _) => { + match &mut target.repr { + PositionRepr::FirstChild(parent) => { + *parent = tree_mutator.make_syntax_mut(parent); + } + PositionRepr::After(child) => { + *child = tree_mutator.make_element_mut(child); + } + }; + } + Change::Replace(target, _) | Change::ReplaceWithMany(target, _) => { + *target = tree_mutator.make_element_mut(target); + } + Change::ReplaceAll(range, _) => { + let start = tree_mutator.make_element_mut(range.start()); + let end = tree_mutator.make_element_mut(range.end()); + + *range = start..=end; + } + } + + // Collect changed elements + match &changes[index as usize] { + Change::Insert(_, element) => changed_elements.push(element.clone()), + Change::InsertAll(_, elements) => changed_elements.extend(elements.iter().cloned()), + Change::Replace(_, Some(element)) => changed_elements.push(element.clone()), + Change::Replace(_, None) => {} + Change::ReplaceWithMany(_, elements) => { + changed_elements.extend(elements.iter().cloned()) + } + Change::ReplaceAll(_, elements) => changed_elements.extend(elements.iter().cloned()), + } + } + + for DependentChange { parent, child } in dependent_changes.into_iter() { + let (input_ancestor, output_ancestor) = match &changes[parent as usize] { + // No change will depend on an insert since changes can only depend on nodes in the root tree + Change::Insert(_, _) | Change::InsertAll(_, _) => unreachable!(), + Change::Replace(target, Some(new_target)) => { + (to_owning_node(target), to_owning_node(new_target)) + } + // Silently drop outdated change + Change::Replace(_, None) => continue, + Change::ReplaceAll(_, _) | Change::ReplaceWithMany(_, _) => { + unimplemented!("cannot resolve changes that depend on replacing many elements") + } + }; + + let upmap_target_node = |target: &SyntaxNode| { + match mappings.upmap_child(target, &input_ancestor, &output_ancestor) { + Ok(it) => it, + Err(MissingMapping(current)) => unreachable!("no mappings exist between {current:?} (ancestor of {input_ancestor:?}) and {output_ancestor:?}"), + } + }; + + let upmap_target = |target: &SyntaxElement| { + match mappings.upmap_child_element(target, &input_ancestor, &output_ancestor) { + Ok(it) => it, + Err(MissingMapping(current)) => unreachable!("no mappings exist between {current:?} (ancestor of {input_ancestor:?}) and {output_ancestor:?}"), + } + }; + + match &mut changes[child as usize] { + Change::Insert(target, _) | Change::InsertAll(target, _) => match &mut target.repr { + PositionRepr::FirstChild(parent) => { + *parent = upmap_target_node(parent); + } + PositionRepr::After(child) => { + *child = upmap_target(child); + } + }, + Change::Replace(target, _) | Change::ReplaceWithMany(target, _) => { + *target = upmap_target(target); + } + Change::ReplaceAll(range, _) => { + *range = upmap_target(range.start())..=upmap_target(range.end()); + } + } + } + + // Apply changes + let mut root = tree_mutator.mutable_clone; + + for change in changes { + match change { + Change::Insert(position, element) => { + let (parent, index) = position.place(); + parent.splice_children(index..index, vec![element]); + } + Change::InsertAll(position, elements) => { + let (parent, index) = position.place(); + parent.splice_children(index..index, elements); + } + Change::Replace(target, None) => { + target.detach(); + } + Change::Replace(SyntaxElement::Node(target), Some(new_target)) if target == root => { + root = new_target.into_node().expect("root node replacement should be a node"); + } + Change::Replace(target, Some(new_target)) => { + let parent = target.parent().unwrap(); + parent.splice_children(target.index()..target.index() + 1, vec![new_target]); + } + Change::ReplaceWithMany(target, elements) => { + let parent = target.parent().unwrap(); + parent.splice_children(target.index()..target.index() + 1, elements); + } + Change::ReplaceAll(range, elements) => { + let start = range.start().index(); + let end = range.end().index(); + let parent = range.start().parent().unwrap(); + parent.splice_children(start..end + 1, elements); + } + } + } + + // Propagate annotations + let annotations = annotations.into_iter().filter_map(|(element, annotation)| { + match mappings.upmap_element(&element, &root) { + // Needed to follow the new tree to find the resulting element + Some(Ok(mapped)) => Some((mapped, annotation)), + // Element did not need to be mapped + None => Some((element, annotation)), + // Element did not make it to the final tree + Some(Err(_)) => None, + } + }); + + let mut annotation_groups = FxHashMap::default(); + + for (element, annotation) in annotations { + annotation_groups.entry(annotation).or_insert(vec![]).push(element); + } + + SyntaxEdit { + old_root: tree_mutator.immutable, + new_root: root, + changed_elements, + annotations: annotation_groups, + } +} + +fn to_owning_node(element: &SyntaxElement) -> SyntaxNode { + match element { + SyntaxElement::Node(node) => node.clone(), + SyntaxElement::Token(token) => token.parent().unwrap().clone(), + } +} + +struct ChangedAncestor { + kind: ChangedAncestorKind, + change_index: usize, +} + +enum ChangedAncestorKind { + Single { node: SyntaxNode }, + Range { _changed_elements: RangeInclusive<SyntaxElement>, _in_parent: SyntaxNode }, +} + +impl ChangedAncestor { + fn single(element: &SyntaxElement, change_index: usize) -> Self { + let kind = match element { + SyntaxElement::Node(node) => ChangedAncestorKind::Single { node: node.clone() }, + SyntaxElement::Token(token) => { + ChangedAncestorKind::Single { node: token.parent().unwrap() } + } + }; + + Self { kind, change_index } + } + + fn multiple(range: &RangeInclusive<SyntaxElement>, change_index: usize) -> Self { + Self { + kind: ChangedAncestorKind::Range { + _changed_elements: range.clone(), + _in_parent: range.start().parent().unwrap(), + }, + change_index, + } + } + + fn affected_range(&self) -> TextRange { + match &self.kind { + ChangedAncestorKind::Single { node } => node.text_range(), + ChangedAncestorKind::Range { _changed_elements: changed_nodes, _in_parent: _ } => { + TextRange::new( + changed_nodes.start().text_range().start(), + changed_nodes.end().text_range().end(), + ) + } + } + } +} + +struct TreeMutator { + immutable: SyntaxNode, + mutable_clone: SyntaxNode, +} + +impl TreeMutator { + fn new(immutable: &SyntaxNode) -> TreeMutator { + let immutable = immutable.clone(); + let mutable_clone = immutable.clone_for_update(); + TreeMutator { immutable, mutable_clone } + } + + fn make_element_mut(&self, element: &SyntaxElement) -> SyntaxElement { + match element { + SyntaxElement::Node(node) => SyntaxElement::Node(self.make_syntax_mut(node)), + SyntaxElement::Token(token) => { + let parent = self.make_syntax_mut(&token.parent().unwrap()); + parent.children_with_tokens().nth(token.index()).unwrap() + } + } + } + + fn make_syntax_mut(&self, node: &SyntaxNode) -> SyntaxNode { + let ptr = SyntaxNodePtr::new(node); + ptr.to_node(&self.mutable_clone) + } +} diff --git a/crates/syntax/src/syntax_editor/mapping.rs b/crates/syntax/src/syntax_editor/mapping.rs new file mode 100644 index 0000000000..9bb5e6d933 --- /dev/null +++ b/crates/syntax/src/syntax_editor/mapping.rs @@ -0,0 +1,272 @@ +//! Maps syntax elements through disjoint syntax nodes. +//! +//! [`SyntaxMappingBuilder`] should be used to create mappings to add to a [`SyntaxEditor`] + +use itertools::Itertools; +use rustc_hash::FxHashMap; + +use crate::{SyntaxElement, SyntaxNode}; + +use super::SyntaxEditor; + +#[derive(Debug, Default)] +pub struct SyntaxMapping { + // important information to keep track of: + // node -> node + // token -> token (implicit in mappings) + // input parent -> output parent (for deep lookups) + + // mappings -> parents + entry_parents: Vec<SyntaxNode>, + node_mappings: FxHashMap<SyntaxNode, MappingEntry>, +} + +impl SyntaxMapping { + pub fn new() -> Self { + Self::default() + } + + /// Like [`SyntaxMapping::upmap_child`] but for syntax elements. + pub fn upmap_child_element( + &self, + child: &SyntaxElement, + input_ancestor: &SyntaxNode, + output_ancestor: &SyntaxNode, + ) -> Result<SyntaxElement, MissingMapping> { + match child { + SyntaxElement::Node(node) => { + self.upmap_child(node, input_ancestor, output_ancestor).map(SyntaxElement::Node) + } + SyntaxElement::Token(token) => { + let upmap_parent = + self.upmap_child(&token.parent().unwrap(), input_ancestor, output_ancestor)?; + + let element = upmap_parent.children_with_tokens().nth(token.index()).unwrap(); + debug_assert!( + element.as_token().is_some_and(|it| it.kind() == token.kind()), + "token upmapping mapped to the wrong node ({token:?} -> {element:?})" + ); + + Ok(element) + } + } + } + + /// Maps a child node of the input ancestor to the corresponding node in + /// the output ancestor. + pub fn upmap_child( + &self, + child: &SyntaxNode, + input_ancestor: &SyntaxNode, + output_ancestor: &SyntaxNode, + ) -> Result<SyntaxNode, MissingMapping> { + debug_assert!( + child == input_ancestor + || child.ancestors().any(|ancestor| &ancestor == input_ancestor) + ); + + // Build a list mapping up to the first mappable ancestor + let to_first_upmap = if child != input_ancestor { + std::iter::successors(Some((child.index(), child.clone())), |(_, current)| { + let parent = current.parent().unwrap(); + + if &parent == input_ancestor { + return None; + } + + Some((parent.index(), parent)) + }) + .map(|(i, _)| i) + .collect::<Vec<_>>() + } else { + vec![] + }; + + // Progressively up-map the input ancestor until we get to the output ancestor + let to_output_ancestor = if input_ancestor != output_ancestor { + self.upmap_to_ancestor(input_ancestor, output_ancestor)? + } else { + vec![] + }; + + let to_map_down = + to_output_ancestor.into_iter().rev().chain(to_first_upmap.into_iter().rev()); + + let mut target = output_ancestor.clone(); + + for index in to_map_down { + target = target + .children_with_tokens() + .nth(index) + .and_then(|it| it.into_node()) + .expect("equivalent ancestor node should be present in target tree"); + } + + debug_assert_eq!(child.kind(), target.kind()); + + Ok(target) + } + + fn upmap_to_ancestor( + &self, + input_ancestor: &SyntaxNode, + output_ancestor: &SyntaxNode, + ) -> Result<Vec<usize>, MissingMapping> { + let mut current = + self.upmap_node_single(input_ancestor).unwrap_or_else(|| input_ancestor.clone()); + let mut upmap_chain = vec![current.index()]; + + loop { + let Some(parent) = current.parent() else { break }; + + if &parent == output_ancestor { + return Ok(upmap_chain); + } + + current = match self.upmap_node_single(&parent) { + Some(next) => next, + None => parent, + }; + upmap_chain.push(current.index()); + } + + Err(MissingMapping(current)) + } + + pub fn upmap_element( + &self, + input: &SyntaxElement, + output_root: &SyntaxNode, + ) -> Option<Result<SyntaxElement, MissingMapping>> { + match input { + SyntaxElement::Node(node) => { + Some(self.upmap_node(node, output_root)?.map(SyntaxElement::Node)) + } + SyntaxElement::Token(token) => { + let upmap_parent = match self.upmap_node(&token.parent().unwrap(), output_root)? { + Ok(it) => it, + Err(err) => return Some(Err(err)), + }; + + let element = upmap_parent.children_with_tokens().nth(token.index()).unwrap(); + debug_assert!( + element.as_token().is_some_and(|it| it.kind() == token.kind()), + "token upmapping mapped to the wrong node ({token:?} -> {element:?})" + ); + + Some(Ok(element)) + } + } + } + + pub fn upmap_node( + &self, + input: &SyntaxNode, + output_root: &SyntaxNode, + ) -> Option<Result<SyntaxNode, MissingMapping>> { + // Try to follow the mapping tree, if it exists + let input_mapping = self.upmap_node_single(input); + let input_ancestor = + input.ancestors().find_map(|ancestor| self.upmap_node_single(&ancestor)); + + match (input_mapping, input_ancestor) { + (Some(input_mapping), _) => { + // A mapping exists at the input, follow along the tree + Some(self.upmap_child(&input_mapping, &input_mapping, output_root)) + } + (None, Some(input_ancestor)) => { + // A mapping exists at an ancestor, follow along the tree + Some(self.upmap_child(input, &input_ancestor, output_root)) + } + (None, None) => { + // No mapping exists at all, is the same position in the final tree + None + } + } + } + + pub fn merge(&mut self, mut other: SyntaxMapping) { + // Remap other's entry parents to be after the current list of entry parents + let remap_base: u32 = self.entry_parents.len().try_into().unwrap(); + + self.entry_parents.append(&mut other.entry_parents); + self.node_mappings.extend(other.node_mappings.into_iter().map(|(node, entry)| { + (node, MappingEntry { parent: entry.parent + remap_base, ..entry }) + })); + } + + /// Follows the input one step along the syntax mapping tree + fn upmap_node_single(&self, input: &SyntaxNode) -> Option<SyntaxNode> { + let MappingEntry { parent, child_slot } = self.node_mappings.get(input)?; + + let output = self.entry_parents[*parent as usize] + .children_with_tokens() + .nth(*child_slot as usize) + .and_then(SyntaxElement::into_node) + .unwrap(); + + debug_assert_eq!(input.kind(), output.kind()); + Some(output) + } + + fn add_mapping(&mut self, syntax_mapping: SyntaxMappingBuilder) { + let SyntaxMappingBuilder { parent_node, node_mappings } = syntax_mapping; + + let parent_entry: u32 = self.entry_parents.len().try_into().unwrap(); + self.entry_parents.push(parent_node); + + let node_entries = node_mappings + .into_iter() + .map(|(node, slot)| (node, MappingEntry { parent: parent_entry, child_slot: slot })); + + self.node_mappings.extend(node_entries); + } +} + +#[derive(Debug)] +pub struct SyntaxMappingBuilder { + parent_node: SyntaxNode, + node_mappings: Vec<(SyntaxNode, u32)>, +} + +impl SyntaxMappingBuilder { + pub fn new(parent_node: SyntaxNode) -> Self { + Self { parent_node, node_mappings: vec![] } + } + + pub fn map_node(&mut self, input: SyntaxNode, output: SyntaxNode) { + debug_assert_eq!(output.parent().as_ref(), Some(&self.parent_node)); + self.node_mappings.push((input, output.index() as u32)); + } + + pub fn map_children( + &mut self, + input: impl Iterator<Item = SyntaxNode>, + output: impl Iterator<Item = SyntaxNode>, + ) { + for pairs in input.zip_longest(output) { + let (input, output) = match pairs { + itertools::EitherOrBoth::Both(l, r) => (l, r), + itertools::EitherOrBoth::Left(_) => { + unreachable!("mapping more input nodes than there are output nodes") + } + itertools::EitherOrBoth::Right(_) => break, + }; + + self.map_node(input, output); + } + } + + pub fn finish(self, editor: &mut SyntaxEditor) { + editor.mappings.add_mapping(self); + } +} + +#[derive(Debug)] +pub struct MissingMapping(pub SyntaxNode); + +#[derive(Debug, Clone, Copy)] +struct MappingEntry { + parent: u32, + child_slot: u32, +} |