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//! Representation of CSS types, and the CSS parsing and matching engine.
//!
//! # Terminology
//! Consider a CSS **stylesheet** like this:
//! ```css
//! @import url("another.css");
//! foo, .bar {
//! fill: red;
//! stroke: green;
//! }
//! #baz { stroke-width: 42; }
//! ```
//! The example contains three **rules**, the first one is an **at-rule*,
//! the other two are **qualified rules**.
//! Each rule is made of two parts, a **prelude** and an optional **block**
//! The prelude is the part until the first `{` or until `;`, depending on
//! whether a block is present. The block is the part between curly braces.
//! Let's look at each rule:
//! `@import` is an **at-rule**. This rule has a prelude, but no block.
//! There are other at-rules like `@media` and some of them may have a block,
//! but librsvg doesn't support those yet.
//! The prelude of the following rule is `foo, .bar`.
//! It is a **selector list** with two **selectors**, one for
//! `foo` elements and one for elements that have the `bar` class.
//! The content of the block between `{}` for a qualified rule is a
//! **declaration list**. The block of the first qualified rule contains two
//! **declarations**, one for the `fill` **property** and one for the
//! `stroke` property.
//! After the first qualified rule, we have a second qualified rule with
//! a single selector for the `#baz` id, with a single declaration for the
//! `stroke-width` property.
//! # Helper crates we use
//! * `cssparser` crate as a CSS tokenizer, and some utilities to
//! parse CSS rules and declarations.
//! * `selectors` crate for the representation of selectors and
//! selector lists, and for the matching engine.
//! Both crates provide very generic implementations of their concepts,
//! and expect the caller to provide implementations of various traits,
//! and to provide types that represent certain things.
//! For example, `cssparser` expects one to provide representations of
//! the following types:
//! * A parsed CSS rule. For `fill: blue;` we have
//! `ParsedProperty::Fill(...)`.
//! * A parsed selector list; we use `SelectorList` from the
//! `selectors` crate.
//! In turn, the `selectors` crate needs a way to navigate and examine
//! one's implementation of an element tree. We provide `impl
//! selectors::Element for RsvgElement` for this. This implementation
//! has methods like "does this element have the id `#foo`", or "give
//! me the next sibling element".
//! Finally, the matching engine ties all of this together with
//! `matches_selector()`. This takes an opaque representation of an
//! element, plus a selector, and returns a bool. We iterate through
//! the rules in the stylesheets and gather the matches; then sort the
//! matches by specificity and apply the result to each element.
use cssparser::{
self, match_ignore_ascii_case, parse_important, AtRuleParser, BasicParseErrorKind, CowRcStr,
DeclarationParser, Parser, ParserInput, ParserState, QualifiedRuleParser, RuleBodyItemParser,
RuleBodyParser, SourceLocation, StyleSheetParser, ToCss,
};
use data_url::mime::Mime;
use language_tags::LanguageTag;
use markup5ever::{self, namespace_url, ns, Namespace, QualName};
use selectors::attr::{AttrSelectorOperation, CaseSensitivity, NamespaceConstraint};
use selectors::matching::{
ElementSelectorFlags, IgnoreNthChildForInvalidation, MatchingContext, MatchingMode,
NeedsSelectorFlags, QuirksMode,
use selectors::parser::ParseRelative;
use selectors::{NthIndexCache, OpaqueElement, SelectorImpl, SelectorList};
use std::cmp::Ordering;
use std::fmt;
use std::str;
use std::str::FromStr;
use crate::element::Element;
use crate::error::*;
use crate::io::{self, BinaryData};
use crate::node::{Node, NodeBorrow, NodeCascade};
use crate::properties::{parse_value, ComputedValues, ParseAs, ParsedProperty};
use crate::rsvg_log;
use crate::session::Session;
use crate::url_resolver::{AllowedUrl, UrlResolver};
/// A parsed CSS declaration
///
/// For example, in the declaration `fill: green !important`, the
/// `prop_name` would be `fill`, the `property` would be
/// `ParsedProperty::Fill(...)` with the green value, and `important`
/// would be `true`.
pub struct Declaration {
pub prop_name: QualName,
pub property: ParsedProperty,
pub important: bool,
}
/// This enum represents the fact that a rule body can be either a
/// declaration or a nested rule.
pub enum RuleBodyItem {
Decl(Declaration),
#[allow(dead_code)] // We don't support nested rules yet
Rule(Rule),
/// Dummy struct required to use `cssparser::DeclarationListParser`
/// It implements `cssparser::DeclarationParser`, which knows how to parse
/// the property/value pairs from a CSS declaration.
pub struct DeclParser;
impl<'i> DeclarationParser<'i> for DeclParser {
type Declaration = RuleBodyItem;
type Error = ValueErrorKind;
/// Parses a CSS declaration like `name: input_value [!important]`
fn parse_value<'t>(
&mut self,
name: CowRcStr<'i>,
input: &mut Parser<'i, 't>,
) -> Result<RuleBodyItem, cssparser::ParseError<'i, Self::Error>> {
let prop_name = QualName::new(None, ns!(), markup5ever::LocalName::from(name.as_ref()));
let property = parse_value(&prop_name, input, ParseAs::Property)?;
let important = input.try_parse(parse_important).is_ok();
Ok(RuleBodyItem::Decl(Declaration {
prop_name,
property,
important,
}))
// cssparser's DeclarationListParser requires this; we just use the dummy
// implementations from cssparser itself. We may want to provide a real
// implementation in the future, although this may require keeping track of the
// CSS parsing state like Servo does.
impl<'i> AtRuleParser<'i> for DeclParser {
type Prelude = ();
type AtRule = RuleBodyItem;
/// We need this dummy implementation as well.
impl<'i> QualifiedRuleParser<'i> for DeclParser {
type QualifiedRule = RuleBodyItem;
impl<'i> RuleBodyItemParser<'i, RuleBodyItem, ValueErrorKind> for DeclParser {
/// We want to parse declarations.
fn parse_declarations(&self) -> bool {
true
/// We don't wanto parse qualified rules though.
fn parse_qualified(&self) -> bool {
false
/// Struct to implement cssparser::QualifiedRuleParser and cssparser::AtRuleParser
pub struct RuleParser {
session: Session,
/// Errors from the CSS parsing process
#[derive(Debug)]
pub enum ParseErrorKind<'i> {
Selector(selectors::parser::SelectorParseErrorKind<'i>),
impl<'i> From<selectors::parser::SelectorParseErrorKind<'i>> for ParseErrorKind<'i> {
fn from(e: selectors::parser::SelectorParseErrorKind<'_>) -> ParseErrorKind<'_> {
ParseErrorKind::Selector(e)
/// A CSS qualified rule (or ruleset)
pub struct QualifiedRule {
selectors: SelectorList<Selector>,
declarations: Vec<Declaration>,
/// Prelude of at-rule used in the AtRuleParser.
pub enum AtRulePrelude {
Import(String),
/// A CSS at-rule (or ruleset)
pub enum AtRule {
/// A CSS rule (or ruleset)
pub enum Rule {
AtRule(AtRule),
QualifiedRule(QualifiedRule),
// Required to implement the `Prelude` associated type in `cssparser::QualifiedRuleParser`
impl<'i> selectors::Parser<'i> for RuleParser {
type Impl = Selector;
type Error = ParseErrorKind<'i>;
fn default_namespace(&self) -> Option<<Self::Impl as SelectorImpl>::NamespaceUrl> {
Some(ns!(svg))
fn namespace_for_prefix(
&self,
_prefix: &<Self::Impl as SelectorImpl>::NamespacePrefix,
) -> Option<<Self::Impl as SelectorImpl>::NamespaceUrl> {
// FIXME: Do we need to keep a lookup table extracted from libxml2's
// XML namespaces?
//
// Or are CSS namespaces completely different, declared elsewhere?
None
fn parse_non_ts_pseudo_class(
location: SourceLocation,
) -> Result<NonTSPseudoClass, cssparser::ParseError<'i, Self::Error>> {
match &*name {
"link" => Ok(NonTSPseudoClass::Link),
"visited" => Ok(NonTSPseudoClass::Visited),
_ => Err(location.new_custom_error(
selectors::parser::SelectorParseErrorKind::UnsupportedPseudoClassOrElement(name),
)),
fn parse_non_ts_functional_pseudo_class(
arguments: &mut Parser<'i, '_>,
"lang" => {
// Comma-separated lists of languages are a Selectors 4 feature,
// but a pretty stable one that hasn't changed in a long time.
let tags = arguments.parse_comma_separated(|arg| {
let language_tag = arg.expect_ident_or_string()?.clone();
LanguageTag::from_str(&language_tag).map_err(|_| {
arg.new_custom_error(selectors::parser::SelectorParseErrorKind::UnsupportedPseudoClassOrElement(language_tag))
})
})?;
arguments.expect_exhausted()?;
Ok(NonTSPseudoClass::Lang(tags))
_ => Err(arguments.new_custom_error(
// `cssparser::StyleSheetParser` is a struct which requires that we provide a type that
// implements `cssparser::QualifiedRuleParser` and `cssparser::AtRuleParser`.
// In turn, `cssparser::QualifiedRuleParser` requires that we
// implement a way to parse the `Prelude` of a ruleset or rule. For
// example, in this ruleset:
// ```css
// foo, .bar { fill: red; stroke: green; }
// ```
// The prelude is the selector list with the `foo` and `.bar` selectors.
// The `parse_prelude` method just uses `selectors::SelectorList`. This
// is what requires the `impl selectors::Parser for RuleParser`.
// Next, the `parse_block` method takes an already-parsed prelude (a selector list),
// and tries to parse the block between braces. It creates a `Rule` out of
// the selector list and the declaration list.
impl<'i> QualifiedRuleParser<'i> for RuleParser {
type Prelude = SelectorList<Selector>;
type QualifiedRule = Rule;
fn parse_prelude<'t>(
) -> Result<Self::Prelude, cssparser::ParseError<'i, Self::Error>> {
SelectorList::parse(self, input, ParseRelative::No).map_err(|e| ParseError {
kind: cssparser::ParseErrorKind::Custom(ValueErrorKind::parse_error(
"Could not parse selector",
location: e.location,
fn parse_block<'t>(
prelude: Self::Prelude,
_start: &ParserState,
) -> Result<Self::QualifiedRule, cssparser::ParseError<'i, Self::Error>> {
let declarations = RuleBodyParser::<_, _, Self::Error>::new(input, &mut DeclParser)
.filter_map(|r| match r {
Ok(RuleBodyItem::Decl(decl)) => Some(decl),
Ok(RuleBodyItem::Rule(_)) => None,
Err(e) => {
rsvg_log!(self.session, "Invalid declaration; ignoring: {:?}", e);
.collect();
Ok(Rule::QualifiedRule(QualifiedRule {
selectors: prelude,
declarations,
// Required by `cssparser::StyleSheetParser`.
// This only handles the `@import` at-rule.
impl<'i> AtRuleParser<'i> for RuleParser {
type Prelude = AtRulePrelude;
type AtRule = Rule;
#[allow(clippy::type_complexity)]
match_ignore_ascii_case! {
&name,
// FIXME: at the moment we ignore media queries
"import" => {
let url = input.expect_url_or_string()?.as_ref().to_owned();
Ok(AtRulePrelude::Import(url))
},
_ => Err(input.new_error(BasicParseErrorKind::AtRuleInvalid(name))),
fn rule_without_block(
) -> Result<Self::AtRule, ()> {
let AtRulePrelude::Import(url) = prelude;
Ok(Rule::AtRule(AtRule::Import(url)))
// When we implement at-rules with blocks, implement the trait's parse_block() method here.
/// Dummy type required by the SelectorImpl trait.
#[allow(clippy::upper_case_acronyms)]
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum NonTSPseudoClass {
Link,
Visited,
Lang(Vec<LanguageTag>),
impl ToCss for NonTSPseudoClass {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
where
W: fmt::Write,
{
match self {
NonTSPseudoClass::Link => write!(dest, "link"),
NonTSPseudoClass::Visited => write!(dest, "visited"),
NonTSPseudoClass::Lang(lang) => write!(
dest,
"lang(\"{}\")",
lang.iter()
.map(ToString::to_string)
.collect::<Vec<_>>()
.join("\",\"")
),
impl selectors::parser::NonTSPseudoClass for NonTSPseudoClass {
fn is_active_or_hover(&self) -> bool {
fn is_user_action_state(&self) -> bool {
/// Dummy type required by the SelectorImpl trait
pub struct PseudoElement;
impl ToCss for PseudoElement {
fn to_css<W>(&self, _dest: &mut W) -> fmt::Result
Ok(())
impl selectors::parser::PseudoElement for PseudoElement {
/// Holds all the types for the SelectorImpl trait
#[derive(Debug, Clone)]
pub struct Selector;
/// Wrapper for attribute values.
/// We use a newtype because the associated type Selector::AttrValue
/// must implement `From<&str>` and `ToCss`, which are foreign traits.
/// The `derive` requirements come from the `selectors` crate.
#[derive(Clone, PartialEq, Eq)]
pub struct AttributeValue(String);
impl From<&str> for AttributeValue {
fn from(s: &str) -> AttributeValue {
AttributeValue(s.to_owned())
impl ToCss for AttributeValue {
use std::fmt::Write;
write!(cssparser::CssStringWriter::new(dest), "{}", &self.0)
impl AsRef<str> for AttributeValue {
fn as_ref(&self) -> &str {
self.0.as_ref()
/// Wrapper for identifier values.
/// Used to implement `ToCss` on the `LocalName` foreign type.
pub struct Identifier(markup5ever::LocalName);
impl From<&str> for Identifier {
fn from(s: &str) -> Identifier {
Identifier(markup5ever::LocalName::from(s))
impl ToCss for Identifier {
cssparser::serialize_identifier(&self.0, dest)
/// Wrapper for local names.
pub struct LocalName(markup5ever::LocalName);
impl From<&str> for LocalName {
fn from(s: &str) -> LocalName {
LocalName(markup5ever::LocalName::from(s))
impl ToCss for LocalName {
/// Wrapper for namespace prefixes.
/// Used to implement `ToCss` on the `markup5ever::Prefix` foreign type.
#[derive(Clone, Default, PartialEq, Eq)]
pub struct NamespacePrefix(markup5ever::Prefix);
impl From<&str> for NamespacePrefix {
fn from(s: &str) -> NamespacePrefix {
NamespacePrefix(markup5ever::Prefix::from(s))
impl ToCss for NamespacePrefix {
impl SelectorImpl for Selector {
type ExtraMatchingData<'a> = ();
type AttrValue = AttributeValue;
type Identifier = Identifier;
type LocalName = LocalName;
type NamespaceUrl = Namespace;
type NamespacePrefix = NamespacePrefix;
type BorrowedNamespaceUrl = Namespace;
type BorrowedLocalName = LocalName;
type NonTSPseudoClass = NonTSPseudoClass;
type PseudoElement = PseudoElement;
/// Newtype wrapper around `Node` so we can implement [`selectors::Element`] for it.
/// `Node` is an alias for [`rctree::Node`], so we can't implement
/// `selectors::Element` directly on it. We implement it on the
/// `RsvgElement` wrapper instead.
#[derive(Clone, PartialEq)]
pub struct RsvgElement(Node);
impl From<Node> for RsvgElement {
fn from(n: Node) -> RsvgElement {
RsvgElement(n)
impl fmt::Debug for RsvgElement {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.0.borrow())
// The selectors crate uses this to examine our tree of elements.
impl selectors::Element for RsvgElement {
/// Converts self into an opaque representation.
fn opaque(&self) -> OpaqueElement {
// The `selectors` crate uses this value just for pointer comparisons, to answer
// the question, "is this element the same as that one?". So, we'll give it a
// reference to our actual node's data, i.e. skip over whatever wrappers there
// are in rctree.
// We use an explicit type here to make it clear what the type is; otherwise you
// may be fooled by the fact that borrow_element() returns a Ref<Element>, not a
// plain reference: &Ref<T> is transient and would get dropped at the end of this
// function, but we want something long-lived.
let element: &Element = &self.0.borrow_element();
OpaqueElement::new::<Element>(element)
fn parent_element(&self) -> Option<Self> {
self.0.parent().map(|n| n.into())
/// Whether the parent node of this element is a shadow root.
fn parent_node_is_shadow_root(&self) -> bool {
// unsupported
/// The host of the containing shadow root, if any.
fn containing_shadow_host(&self) -> Option<Self> {
/// Whether we're matching on a pseudo-element.
fn is_pseudo_element(&self) -> bool {
/// Skips non-element nodes
fn prev_sibling_element(&self) -> Option<Self> {
let mut sibling = self.0.previous_sibling();
while let Some(ref sib) = sibling {
if sib.is_element() {
return sibling.map(|n| n.into());
sibling = sib.previous_sibling();
fn next_sibling_element(&self) -> Option<Self> {
let mut sibling = self.0.next_sibling();
sibling = sib.next_sibling();
fn is_html_element_in_html_document(&self) -> bool {
fn has_local_name(&self, local_name: &LocalName) -> bool {
self.0.borrow_element().element_name().local == local_name.0
/// Empty string for no namespace
fn has_namespace(&self, ns: &Namespace) -> bool {
self.0.borrow_element().element_name().ns == *ns
/// Whether this element and the `other` element have the same local name and namespace.
fn is_same_type(&self, other: &Self) -> bool {
self.0.borrow_element().element_name() == other.0.borrow_element().element_name()
fn attr_matches(
ns: &NamespaceConstraint<&Namespace>,
local_name: &LocalName,
operation: &AttrSelectorOperation<&AttributeValue>,
) -> bool {
self.0
.borrow_element()
.get_attributes()
.iter()
.find(|(attr, _)| {
// do we have an attribute that matches the namespace and local_name?
match *ns {
NamespaceConstraint::Any => local_name.0 == attr.local,
NamespaceConstraint::Specific(ns) => {
QualName::new(None, ns.clone(), local_name.0.clone()) == *attr
.map(|(_, value)| {
// we have one; does the attribute's value match the expected operation?
operation.eval_str(value)
.unwrap_or(false)
fn match_non_ts_pseudo_class(
pc: &<Self::Impl as SelectorImpl>::NonTSPseudoClass,
_context: &mut MatchingContext<'_, Self::Impl>,
) -> bool
where {
match pc {
NonTSPseudoClass::Link => self.is_link(),
NonTSPseudoClass::Visited => false,
NonTSPseudoClass::Lang(css_lang) => self
.0
.get_computed_values()
.xml_lang()
.as_ref()
.map_or(false, |e_lang| {
css_lang
.any(|l| l.is_language_range() && l.matches(e_lang))
}),
fn match_pseudo_element(
_pe: &<Self::Impl as SelectorImpl>::PseudoElement,
/// Whether this element is a `link`.
fn is_link(&self) -> bool {
// Style as link only if href is specified at all.
// The SVG and CSS specifications do not seem to clearly
// say what happens when you have an `<svg:a>` tag with no
// `(xlink:|svg:)href` attribute. However, both Firefox and Chromium
// consider a bare `<svg:a>` element with no href to be NOT
// a link, so to avoid nasty surprises, we do the same.
// Empty href's, however, ARE considered links.
self.0.is_element()
&& match *self.0.borrow_element_data() {
crate::element::ElementData::Link(ref link) => link.link.is_some(),
_ => false,
/// Returns whether the element is an HTML `<slot>` element.
fn is_html_slot_element(&self) -> bool {
fn has_id(&self, id: &Identifier, case_sensitivity: CaseSensitivity) -> bool {
.get_id()
.map(|self_id| case_sensitivity.eq(self_id.as_bytes(), id.0.as_bytes()))
fn has_class(&self, name: &Identifier, case_sensitivity: CaseSensitivity) -> bool {
.get_class()
.map(|classes| {
classes
.split_whitespace()
.any(|class| case_sensitivity.eq(class.as_bytes(), name.0.as_bytes()))
fn imported_part(&self, _name: &Identifier) -> Option<Identifier> {
fn is_part(&self, _name: &Identifier) -> bool {
/// Returns whether this element matches `:empty`.
/// That is, whether it does not contain any child element or any non-zero-length text node.
/// See <http://dev.w3.org/csswg/selectors-3/#empty-pseudo>.
fn is_empty(&self) -> bool {
// .all() returns true for the empty iterator
.children()
.all(|child| child.is_chars() && child.borrow_chars().is_empty())
/// Returns whether this element matches `:root`,
/// i.e. whether it is the root element of a document.
/// Note: this can be false even if `.parent_element()` is `None`
/// if the parent node is a `DocumentFragment`.
fn is_root(&self) -> bool {
self.0.parent().is_none()
/// Returns the first child element of this element.
fn first_element_child(&self) -> Option<Self> {
.find(|child| child.is_element())
.map(|n| n.into())
/// Applies the given selector flags to this element.
fn apply_selector_flags(&self, _: ElementSelectorFlags) {
todo!()
/// Origin for a stylesheet, per CSS 2.2.
/// This is used when sorting selector matches according to their origin and specificity.
/// CSS2.2: <https://www.w3.org/TR/CSS22/cascade.html#cascading-order>
#[derive(Copy, Clone, Eq, Ord, PartialEq, PartialOrd)]
pub enum Origin {
UserAgent,
User,
Author,
/// A parsed CSS stylesheet.
pub struct Stylesheet {
origin: Origin,
qualified_rules: Vec<QualifiedRule>,
/// A match during the selector matching process
/// This struct comes from [`Stylesheet::get_matches`], and represents
/// that a certain node matched a CSS rule which has a selector with a
/// certain `specificity`. The stylesheet's `origin` is also given here.
/// This type implements [`Ord`] so a list of `Match` can be sorted.
/// That implementation does ordering based on origin and specificity
/// as per <https://www.w3.org/TR/CSS22/cascade.html#cascading-order>.
struct Match<'a> {
specificity: u32,
declaration: &'a Declaration,
impl<'a> Ord for Match<'a> {
fn cmp(&self, other: &Self) -> Ordering {
match self.origin.cmp(&other.origin) {
Ordering::Equal => self.specificity.cmp(&other.specificity),
o => o,
impl<'a> PartialOrd for Match<'a> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
impl<'a> PartialEq for Match<'a> {
fn eq(&self, other: &Self) -> bool {
self.origin == other.origin && self.specificity == other.specificity
impl<'a> Eq for Match<'a> {}
impl Stylesheet {
fn empty(origin: Origin) -> Stylesheet {
Stylesheet {
origin,
qualified_rules: Vec::new(),
/// Parses a new stylesheet from CSS data in a string.
/// The `url_resolver_url` is required for `@import` rules, so that librsvg can determine if
/// the requested path is allowed.
pub fn from_data(
buf: &str,
url_resolver: &UrlResolver,
) -> Result<Self, LoadingError> {
let mut stylesheet = Stylesheet::empty(origin);
stylesheet.add_rules_from_string(buf, url_resolver, session)?;
Ok(stylesheet)
/// Parses a new stylesheet by loading CSS data from a URL.
pub fn from_href(
aurl: &AllowedUrl,
stylesheet.load(aurl, session)?;
/// Parses the CSS rules in `buf` and appends them to the stylesheet.
/// If there is an `@import` rule, its rules will be recursively added into the
/// stylesheet, in the order in which they appear.
fn add_rules_from_string(
) -> Result<(), LoadingError> {
let mut input = ParserInput::new(buf);
let mut parser = Parser::new(&mut input);
let mut rule_parser = RuleParser {
session: session.clone(),
StyleSheetParser::new(&mut parser, &mut rule_parser)
Ok(rule) => Some(rule),
rsvg_log!(session, "Invalid rule; ignoring: {:?}", e);
.for_each(|rule| match rule {
Rule::AtRule(AtRule::Import(url)) => match url_resolver.resolve_href(&url) {
Ok(aurl) => {
// ignore invalid imports
let _ = self.load(&aurl, session.clone());
rsvg_log!(session, "Not loading stylesheet from \"{}\": {}", url, e);
Rule::QualifiedRule(qr) => self.qualified_rules.push(qr),
});
/// Parses a stylesheet referenced by an URL
fn load(&mut self, aurl: &AllowedUrl, session: Session) -> Result<(), LoadingError> {
io::acquire_data(aurl, None)
.map_err(LoadingError::from)
.and_then(|data| {
let BinaryData {
data: bytes,
mime_type,
} = data;
if is_text_css(&mime_type) {
Ok(bytes)
} else {
rsvg_log!(session, "\"{}\" is not of type text/css; ignoring", aurl);
Err(LoadingError::BadCss)
.and_then(|bytes| {
String::from_utf8(bytes).map_err(|_| {
rsvg_log!(
session,
"\"{}\" does not contain valid UTF-8 CSS data; ignoring",
aurl
);
LoadingError::BadCss
.and_then(|utf8| {
let url = (**aurl).clone();
self.add_rules_from_string(&utf8, &UrlResolver::new(Some(url)), session)
/// Appends the style declarations that match a specified node to a given vector
fn get_matches<'a>(
&'a self,
node: &Node,
match_ctx: &mut MatchingContext<'_, Selector>,
acc: &mut Vec<Match<'a>>,
) {
for rule in &self.qualified_rules {
for selector in &rule.selectors.0 {
// This magic call is stolen from selectors::matching::matches_selector_list()
let matches = selectors::matching::matches_selector(
selector,
0,
None,
&RsvgElement(node.clone()),
match_ctx,
if matches {
for decl in rule.declarations.iter() {
acc.push(Match {
declaration: decl,
specificity: selector.specificity(),
origin: self.origin,
fn is_text_css(mime_type: &Mime) -> bool {
mime_type.type_ == "text" && mime_type.subtype == "css"
/// Runs the CSS cascade on the specified tree from all the stylesheets
pub fn cascade(
root: &mut Node,
ua_stylesheets: &[Stylesheet],
author_stylesheets: &[Stylesheet],
user_stylesheets: &[Stylesheet],
session: &Session,
for mut node in root.descendants().filter(|n| n.is_element()) {
let mut matches = Vec::new();
// xml:lang needs to be inherited before selector matching, so it
// can't be done in the usual SpecifiedValues::to_computed_values,
// which is called by cascade() and runs after matching.
let parent = node.parent().clone();
node.borrow_element_mut().inherit_xml_lang(parent);
let mut cache = NthIndexCache::default();
let mut match_ctx = MatchingContext::new(
MatchingMode::Normal,
// FIXME: how the fuck does one set up a bloom filter here?
&mut cache,
QuirksMode::NoQuirks,
NeedsSelectorFlags::No,
IgnoreNthChildForInvalidation::No,
for s in ua_stylesheets
.chain(author_stylesheets)
.chain(user_stylesheets)
s.get_matches(&node, &mut match_ctx, &mut matches);
matches.as_mut_slice().sort();
let mut element = node.borrow_element_mut();
for m in matches {
element.apply_style_declaration(m.declaration, m.origin);
element.set_style_attribute(session);
let values = ComputedValues::default();
root.cascade(&values);
#[cfg(test)]
mod tests {
use super::*;
use selectors::Element;
use crate::document::Document;
use crate::is_element_of_type;
#[test]
fn xml_lang() {
let document = Document::load_from_bytes(
br#"<?xml version="1.0" encoding="UTF-8"?>
<svg xmlns="http://www.w3.org/2000/svg" xml:lang="zh">
<text id="a" x="10" y="10" width="30" height="30"></text>
<text id="b" x="10" y="20" width="30" height="30" xml:lang="en"></text>
</svg>
"#,
let a = document.lookup_internal_node("a").unwrap();
assert_eq!(
a.borrow_element()
.unwrap()
.as_str(),
"zh"
let b = document.lookup_internal_node("b").unwrap();
b.borrow_element()
"en"
fn impl_element() {
<svg xmlns="http://www.w3.org/2000/svg" id="a">
<rect id="b" x="10" y="10" width="30" height="30"/>
<circle id="c" cx="10" cy="10" r="10"/>
<rect id="d" class="foo bar"/>
let c = document.lookup_internal_node("c").unwrap();
let d = document.lookup_internal_node("d").unwrap();
// Node types
assert!(is_element_of_type!(a, Svg));
assert!(is_element_of_type!(b, Rect));
assert!(is_element_of_type!(c, Circle));
assert!(is_element_of_type!(d, Rect));
let a = RsvgElement(a);
let b = RsvgElement(b);
let c = RsvgElement(c);
let d = RsvgElement(d);
// Tree navigation
assert_eq!(a.parent_element(), None);
assert_eq!(b.parent_element(), Some(a.clone()));
assert_eq!(c.parent_element(), Some(a.clone()));
assert_eq!(d.parent_element(), Some(a.clone()));
assert_eq!(b.next_sibling_element(), Some(c.clone()));
assert_eq!(c.next_sibling_element(), Some(d.clone()));
assert_eq!(d.next_sibling_element(), None);
assert_eq!(b.prev_sibling_element(), None);
assert_eq!(c.prev_sibling_element(), Some(b.clone()));
assert_eq!(d.prev_sibling_element(), Some(c.clone()));
// Other operations
assert!(a.has_local_name(&LocalName::from("svg")));
assert!(a.has_namespace(&ns!(svg)));
assert!(!a.is_same_type(&b));
assert!(b.is_same_type(&d));
assert!(a.has_id(
&Identifier::from("a"),
CaseSensitivity::AsciiCaseInsensitive
));
assert!(!b.has_id(
&Identifier::from("foo"),
assert!(d.has_class(
&Identifier::from("bar"),
assert!(!a.has_class(
assert!(d.is_empty());
assert!(!a.is_empty());