Refactor and fix style folding

This commit is contained in:
Laurenz 2022-02-05 12:41:42 +01:00
parent 90fb28b4b6
commit 5d05c3f68a
6 changed files with 96 additions and 126 deletions

View File

@ -148,7 +148,7 @@ fn process_const(
if attr.path.is_ident("fold") {
let func: syn::Expr = attr.parse_args()?;
folder = Some(quote! {
const FOLDABLE: bool = true;
const FOLDING: bool = true;
fn fold(inner: Self::Value, outer: Self::Value) -> Self::Value {
let f: fn(Self::Value, Self::Value) -> Self::Value = #func;
@ -179,7 +179,7 @@ fn process_const(
const NAME: &'static str = #name;
fn class_id() -> TypeId {
fn node_id() -> TypeId {
TypeId::of::<#self_ty>()
}

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@ -3,11 +3,6 @@ use std::fmt::{self, Debug, Formatter};
use std::hash::{Hash, Hasher};
use std::sync::Arc;
// TODO(style): Possible optimizations:
// - Ref-count map for cheaper cloning and smaller footprint
// - Store map in `Option` to make empty maps non-allocating
// - Store small properties inline
/// An item with associated styles.
#[derive(PartialEq, Clone, Hash)]
pub struct Styled<T> {
@ -68,15 +63,6 @@ impl StyleMap {
/// Set the value for a style property.
pub fn set<P: Property>(&mut self, key: P, value: P::Value) {
for entry in &mut self.0 {
if entry.is::<P>() {
let prev = entry.downcast::<P>().unwrap();
let folded = P::fold(value, prev.clone());
*entry = Entry::new(key, folded);
return;
}
}
self.0.push(Entry::new(key, value));
}
@ -121,14 +107,7 @@ impl StyleMap {
/// style maps, whereas `chain` would be used during layouting to combine
/// immutable style maps from different levels of the hierarchy.
pub fn apply(&mut self, outer: &Self) {
for outer in &outer.0 {
if let Some(inner) = self.0.iter_mut().find(|inner| inner.is_same(outer)) {
*inner = inner.fold(outer);
continue;
}
self.0.push(outer.clone());
}
self.0.splice(0 .. 0, outer.0.clone());
}
/// Subtract `other` from `self` in-place, keeping only styles that are in
@ -144,7 +123,7 @@ impl StyleMap {
}
/// Whether two style maps are equal when filtered down to properties of the
/// class `T`.
/// node `T`.
pub fn compatible<T: 'static>(&self, other: &Self) -> bool {
let f = |entry: &&Entry| entry.is_of::<T>();
self.0.iter().filter(f).count() == other.0.iter().filter(f).count()
@ -154,7 +133,7 @@ impl StyleMap {
impl Debug for StyleMap {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
for entry in &self.0 {
for entry in self.0.iter().rev() {
writeln!(f, "{:#?}", entry)?;
}
Ok(())
@ -176,23 +155,26 @@ impl PartialEq for StyleMap {
/// matches further up the chain.
#[derive(Clone, Copy, Hash)]
pub struct StyleChain<'a> {
/// The first map in the chain.
/// The first link in the chain.
first: Link<'a>,
/// The remaining maps in the chain.
/// The remaining links in the chain.
outer: Option<&'a Self>,
}
/// The two kinds of links in the chain.
#[derive(Clone, Copy, Hash)]
enum Link<'a> {
/// Just a map with styles.
Map(&'a StyleMap),
/// A barrier that, in combination with one more such barrier, stops scoped
/// styles for the node with this type id.
Barrier(TypeId),
}
impl<'a> StyleChain<'a> {
/// Start a new style chain with a root map.
pub fn new(map: &'a StyleMap) -> Self {
Self { first: Link::Map(map), outer: None }
pub fn new(first: &'a StyleMap) -> Self {
Self { first: Link::Map(first), outer: None }
}
/// Get the (folded) value of a copyable style property.
@ -207,7 +189,7 @@ impl<'a> StyleChain<'a> {
where
P::Value: Copy,
{
self.get_impl(key, 0)
self.get_cloned(key)
}
/// Get a reference to a style property's value.
@ -222,7 +204,7 @@ impl<'a> StyleChain<'a> {
where
P: Nonfolding,
{
self.get_ref_impl(key, 0)
self.values(key).next().unwrap_or_else(|| P::default_ref())
}
/// Get the (folded) value of any style property.
@ -234,7 +216,15 @@ impl<'a> StyleChain<'a> {
/// Returns the property's default value if no map in the chain contains an
/// entry for it.
pub fn get_cloned<P: Property>(self, key: P) -> P::Value {
self.get_impl(key, 0)
if P::FOLDING {
self.values(key)
.cloned()
.chain(std::iter::once(P::default()))
.reduce(P::fold)
.unwrap()
} else {
self.values(key).next().cloned().unwrap_or_else(P::default)
}
}
/// Insert a barrier into the style chain.
@ -242,81 +232,60 @@ impl<'a> StyleChain<'a> {
/// Barriers interact with [scoped](StyleMap::scoped) styles: A scoped style
/// can still be read through a single barrier (the one of the node it
/// _should_ apply to), but a second barrier will make it invisible.
pub fn barred<'b>(&'b self, class: TypeId) -> StyleChain<'b> {
if self.needs_barrier(class) {
pub fn barred<'b>(&'b self, node: TypeId) -> StyleChain<'b> {
if self
.maps()
.any(|map| map.0.iter().any(|entry| entry.scoped && entry.is_of_same(node)))
{
StyleChain {
first: Link::Barrier(class),
first: Link::Barrier(node),
outer: Some(self),
}
} else {
*self
}
}
}
impl<'a> StyleChain<'a> {
fn get_impl<P: Property>(self, key: P, depth: usize) -> P::Value {
let (value, depth) = self.process(key, depth);
if let Some(value) = value.cloned() {
if P::FOLDABLE {
if let Some(outer) = self.outer {
P::fold(value, outer.get_cloned(key))
} else {
P::fold(value, P::default())
}
} else {
value
/// Iterate over all values for the given property in the chain.
fn values<P: Property>(self, _: P) -> impl Iterator<Item = &'a P::Value> {
let mut depth = 0;
self.links().flat_map(move |link| {
let mut entries: &[Entry] = &[];
match link {
Link::Map(map) => entries = &map.0,
Link::Barrier(id) => depth += (id == P::node_id()) as usize,
}
} else if let Some(outer) = self.outer {
outer.get_impl(key, depth)
} else {
P::default()
}
entries
.iter()
.rev()
.filter(move |entry| entry.is::<P>() && (!entry.scoped || depth <= 1))
.filter_map(|entry| entry.downcast::<P>())
})
}
fn get_ref_impl<P: Property>(self, key: P, depth: usize) -> &'a P::Value
where
P: Nonfolding,
{
let (value, depth) = self.process(key, depth);
if let Some(value) = value {
value
} else if let Some(outer) = self.outer {
outer.get_ref_impl(key, depth)
} else {
P::default_ref()
}
/// Iterate over the links of the chain.
fn links(self) -> impl Iterator<Item = Link<'a>> {
let mut cursor = Some(self);
std::iter::from_fn(move || {
let Self { first, outer } = cursor?;
cursor = outer.copied();
Some(first)
})
}
fn process<P: Property>(self, _: P, depth: usize) -> (Option<&'a P::Value>, usize) {
match self.first {
Link::Map(map) => (
map.0
.iter()
.find(|entry| entry.is::<P>() && (!entry.scoped || depth <= 1))
.and_then(|entry| entry.downcast::<P>()),
depth,
),
Link::Barrier(class) => (None, depth + (P::class_id() == class) as usize),
}
}
fn needs_barrier(self, class: TypeId) -> bool {
if let Link::Map(map) = self.first {
if map.0.iter().any(|entry| entry.is_of_same(class)) {
return true;
}
}
self.outer.map_or(false, |outer| outer.needs_barrier(class))
/// Iterate over the map links of the chain.
fn maps(self) -> impl Iterator<Item = &'a StyleMap> {
self.links().filter_map(|link| match link {
Link::Map(map) => Some(map),
Link::Barrier(_) => None,
})
}
}
impl Debug for StyleChain<'_> {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
self.first.fmt(f)?;
if let Some(outer) = self.outer {
outer.fmt(f)?;
for link in self.links() {
link.fmt(f)?;
}
Ok(())
}
@ -334,55 +303,56 @@ impl Debug for Link<'_> {
/// An entry for a single style property.
#[derive(Clone)]
struct Entry {
p: Arc<dyn Bounds>,
pair: Arc<dyn Bounds>,
scoped: bool,
}
impl Entry {
fn new<P: Property>(key: P, value: P::Value) -> Self {
Self { p: Arc::new((key, value)), scoped: false }
Self {
pair: Arc::new((key, value)),
scoped: false,
}
}
fn is<P: Property>(&self) -> bool {
self.p.style_id() == TypeId::of::<P>()
}
fn is_same(&self, other: &Self) -> bool {
self.p.style_id() == other.p.style_id()
self.pair.style_id() == TypeId::of::<P>()
}
fn is_of<T: 'static>(&self) -> bool {
self.p.class_id() == TypeId::of::<T>()
self.pair.node_id() == TypeId::of::<T>()
}
fn is_of_same(&self, class: TypeId) -> bool {
self.p.class_id() == class
fn is_of_same(&self, node: TypeId) -> bool {
self.pair.node_id() == node
}
fn downcast<P: Property>(&self) -> Option<&P::Value> {
self.p.as_any().downcast_ref()
}
fn fold(&self, outer: &Self) -> Self {
self.p.fold(outer)
self.pair.as_any().downcast_ref()
}
}
impl Debug for Entry {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
self.p.dyn_fmt(f)
f.write_str("#[")?;
self.pair.dyn_fmt(f)?;
if self.scoped {
f.write_str(" (scoped)")?;
}
f.write_str("]")
}
}
impl PartialEq for Entry {
fn eq(&self, other: &Self) -> bool {
self.p.dyn_eq(other)
self.pair.dyn_eq(other) && self.scoped == other.scoped
}
}
impl Hash for Entry {
fn hash<H: Hasher>(&self, state: &mut H) {
state.write_u64(self.p.hash64());
state.write_u64(self.pair.hash64());
state.write_u8(self.scoped as u8);
}
}
@ -390,7 +360,7 @@ impl Hash for Entry {
///
/// This trait is not intended to be implemented manually, but rather through
/// the `#[properties]` proc-macro.
pub trait Property: Copy + Sync + Send + 'static {
pub trait Property: Sync + Send + 'static {
/// The type of value that is returned when getting this property from a
/// style map. For example, this could be [`Length`](crate::geom::Length)
/// for a `WIDTH` property.
@ -400,10 +370,10 @@ pub trait Property: Copy + Sync + Send + 'static {
const NAME: &'static str;
/// Whether the property needs folding.
const FOLDABLE: bool = false;
const FOLDING: bool = false;
/// The type id of the class this property belongs to.
fn class_id() -> TypeId;
/// The type id of the node this property belongs to.
fn node_id() -> TypeId;
/// The default value of the property.
fn default() -> Self::Value;
@ -437,9 +407,8 @@ trait Bounds: Sync + Send + 'static {
fn dyn_fmt(&self, f: &mut Formatter) -> fmt::Result;
fn dyn_eq(&self, other: &Entry) -> bool;
fn hash64(&self) -> u64;
fn class_id(&self) -> TypeId;
fn node_id(&self) -> TypeId;
fn style_id(&self) -> TypeId;
fn fold(&self, outer: &Entry) -> Entry;
}
impl<P: Property> Bounds for (P, P::Value) {
@ -448,11 +417,11 @@ impl<P: Property> Bounds for (P, P::Value) {
}
fn dyn_fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "#[{} = {:?}]", P::NAME, self.1)
write!(f, "{} = {:?}", P::NAME, self.1)
}
fn dyn_eq(&self, other: &Entry) -> bool {
self.style_id() == other.p.style_id()
self.style_id() == other.pair.style_id()
&& if let Some(other) = other.downcast::<P>() {
&self.1 == other
} else {
@ -467,17 +436,11 @@ impl<P: Property> Bounds for (P, P::Value) {
state.finish()
}
fn class_id(&self) -> TypeId {
P::class_id()
fn node_id(&self) -> TypeId {
P::node_id()
}
fn style_id(&self) -> TypeId {
TypeId::of::<P>()
}
fn fold(&self, outer: &Entry) -> Entry {
let outer = outer.downcast::<P>().unwrap();
let combined = P::fold(self.1.clone(), outer.clone());
Entry::new(self.0, combined)
}
}

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@ -25,8 +25,8 @@ D
#set page(width: 80pt, height: 30pt)
Fi[#set page(width: 80pt);rst]
[#set page(width: 70pt); Second]
[#set page(width: 80pt); First]
#pagebreak()
#pagebreak()
#pagebreak()
Fourth

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@ -8,3 +8,10 @@
[First],
list([A], [B])
)
---
// Ensure that constructor styles win, but not over outer styles.
#set par(align: center)
#par(align: right)[
A #rect(width: 2cm, fill: conifer, padding: 4pt)[B]
]