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use std::{
cell::{Ref, RefCell, RefMut},
collections::BTreeMap,
};
use crate::ast::CssStmt;
#[derive(Debug, Clone)]
pub(super) struct CssTree {
stmts: Vec<RefCell<Option<CssStmt>>>,
pub parent_to_child: BTreeMap<CssTreeIdx, Vec<CssTreeIdx>>,
pub child_to_parent: BTreeMap<CssTreeIdx, CssTreeIdx>,
}
#[derive(Debug, Copy, Clone, Hash, Eq, PartialEq, PartialOrd, Ord)]
#[repr(transparent)]
pub(super) struct CssTreeIdx(usize);
impl CssTree {
pub const ROOT: CssTreeIdx = CssTreeIdx(0);
pub fn new() -> Self {
let mut tree = Self {
stmts: Vec::new(),
parent_to_child: BTreeMap::new(),
child_to_parent: BTreeMap::new(),
};
tree.stmts.push(RefCell::new(None));
tree
}
pub fn get(&self, idx: CssTreeIdx) -> Ref<Option<CssStmt>> {
self.stmts[idx.0].borrow()
}
pub fn get_mut(&self, idx: CssTreeIdx) -> RefMut<Option<CssStmt>> {
self.stmts[idx.0].borrow_mut()
}
pub fn finish(self) -> Vec<CssStmt> {
let mut idx = 1;
while idx < self.stmts.len() - 1 {
if self.stmts[idx].borrow().is_none() || !self.has_children(CssTreeIdx(idx)) {
idx += 1;
continue;
}
self.apply_children(CssTreeIdx(idx));
idx += 1;
}
self.stmts
.into_iter()
.filter_map(RefCell::into_inner)
.collect()
}
fn apply_children(&self, parent: CssTreeIdx) {
for &child in &self.parent_to_child[&parent] {
if self.has_children(child) {
self.apply_children(child);
}
match self.stmts[child.0].borrow_mut().take() {
Some(child) => self.add_child_to_parent(child, parent),
None => continue,
};
}
}
fn has_children(&self, parent: CssTreeIdx) -> bool {
self.parent_to_child.contains_key(&parent)
}
fn add_child_to_parent(&self, child: CssStmt, parent_idx: CssTreeIdx) {
let mut parent = self.stmts[parent_idx.0].borrow_mut().take();
match &mut parent {
Some(CssStmt::RuleSet { body, .. }) => body.push(child),
Some(CssStmt::Style(..) | CssStmt::Comment(..) | CssStmt::Import(..)) | None => {
unreachable!()
}
Some(CssStmt::Media(media, ..)) => {
media.body.push(child);
}
Some(CssStmt::UnknownAtRule(at_rule, ..)) => {
at_rule.body.push(child);
}
Some(CssStmt::Supports(supports, ..)) => {
supports.body.push(child);
}
Some(CssStmt::KeyframesRuleSet(keyframes)) => {
keyframes.body.push(child);
}
}
self.stmts[parent_idx.0]
.borrow_mut()
.replace(parent.unwrap());
}
pub fn add_child(&mut self, child: CssStmt, parent_idx: CssTreeIdx) -> CssTreeIdx {
let child_idx = self.add_stmt_inner(child);
self.parent_to_child
.entry(parent_idx)
.or_default()
.push(child_idx);
self.child_to_parent.insert(child_idx, parent_idx);
child_idx
}
pub fn link_child_to_parent(&mut self, child_idx: CssTreeIdx, parent_idx: CssTreeIdx) {
self.parent_to_child
.entry(parent_idx)
.or_default()
.push(child_idx);
self.child_to_parent.insert(child_idx, parent_idx);
}
pub fn has_following_sibling(&self, child: CssTreeIdx) -> bool {
if child == Self::ROOT {
return false;
}
let parent_idx = self.child_to_parent.get(&child).unwrap();
let parent_children = self.parent_to_child.get(parent_idx).unwrap();
let child_pos = parent_children
.iter()
.position(|child_idx| *child_idx == child)
.unwrap();
child_pos + 1 < parent_children.len()
}
pub fn add_stmt(&mut self, child: CssStmt, parent: Option<CssTreeIdx>) -> CssTreeIdx {
match parent {
Some(parent) => self.add_child(child, parent),
None => self.add_child(child, Self::ROOT),
}
}
fn add_stmt_inner(&mut self, stmt: CssStmt) -> CssTreeIdx {
let idx = CssTreeIdx(self.stmts.len());
self.stmts.push(RefCell::new(Some(stmt)));
idx
}
}