ruff/crates/ty_ide/src/find_node.rs

107 lines
3.2 KiB
Rust

use ruff_python_ast::visitor::source_order::{SourceOrderVisitor, TraversalSignal};
use ruff_python_ast::AnyNodeRef;
use ruff_text_size::{Ranged, TextRange};
use std::fmt;
use std::fmt::Formatter;
/// Returns the node with a minimal range that fully contains `range`.
///
/// If `range` is empty and falls within a parser *synthesized* node generated during error recovery,
/// then the first node with the given range is returned.
///
/// ## Panics
/// Panics if `range` is not contained within `root`.
pub(crate) fn covering_node(root: AnyNodeRef, range: TextRange) -> CoveringNode {
struct Visitor<'a> {
range: TextRange,
found: bool,
ancestors: Vec<AnyNodeRef<'a>>,
}
impl<'a> SourceOrderVisitor<'a> for Visitor<'a> {
fn enter_node(&mut self, node: AnyNodeRef<'a>) -> TraversalSignal {
// If the node fully contains the range, than it is a possible match but traverse into its children
// to see if there's a node with a narrower range.
if !self.found && node.range().contains_range(self.range) {
self.ancestors.push(node);
TraversalSignal::Traverse
} else {
TraversalSignal::Skip
}
}
fn leave_node(&mut self, node: AnyNodeRef<'a>) {
if !self.found && self.ancestors.last() == Some(&node) {
self.found = true;
}
}
}
assert!(
root.range().contains_range(range),
"Range is not contained within root"
);
let mut visitor = Visitor {
range,
found: false,
ancestors: Vec::new(),
};
root.visit_source_order(&mut visitor);
let minimal = visitor.ancestors.pop().unwrap_or(root);
CoveringNode {
node: minimal,
ancestors: visitor.ancestors,
}
}
/// The node with a minimal range that fully contains the search range.
pub(crate) struct CoveringNode<'a> {
/// The node with a minimal range that fully contains the search range.
node: AnyNodeRef<'a>,
/// The node's ancestor (the spine up to the root).
ancestors: Vec<AnyNodeRef<'a>>,
}
impl<'a> CoveringNode<'a> {
pub(crate) fn node(&self) -> AnyNodeRef<'a> {
self.node
}
/// Returns the node's parent.
pub(crate) fn parent(&self) -> Option<AnyNodeRef<'a>> {
self.ancestors.last().copied()
}
/// Finds the minimal node that fully covers the range and fulfills the given predicate.
pub(crate) fn find(mut self, f: impl Fn(AnyNodeRef<'a>) -> bool) -> Result<Self, Self> {
if f(self.node) {
return Ok(self);
}
match self.ancestors.iter().rposition(|node| f(*node)) {
Some(index) => {
let node = self.ancestors[index];
self.ancestors.truncate(index);
Ok(Self {
node,
ancestors: self.ancestors,
})
}
None => Err(self),
}
}
}
impl fmt::Debug for CoveringNode<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
f.debug_tuple("NodeWithAncestors")
.field(&self.node)
.finish()
}
}