1 files changed, 305 insertions, 0 deletions
diff --git a/servo/components/style/stylesheets/document_rule.rs b/servo/components/style/stylesheets/document_rule.rs
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+++ b/servo/components/style/stylesheets/document_rule.rs
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+//! [@document rules](https://www.w3.org/TR/2012/WD-css3-conditional-20120911/#at-document)
+//! initially in CSS Conditional Rules Module Level 3, @document has been postponed to the level 4.
+//! We implement the prefixed `@-moz-document`.
+
+use crate::media_queries::Device;
+use crate::parser::{Parse, ParserContext};
+use crate::shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked};
+use crate::shared_lock::{SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
+use crate::str::CssStringWriter;
+use crate::stylesheets::CssRules;
+use crate::values::CssUrl;
+use cssparser::{BasicParseErrorKind, Parser, SourceLocation};
+#[cfg(feature = "gecko")]
+use malloc_size_of::{MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
+use servo_arc::Arc;
+use std::fmt::{self, Write};
+use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+
+#[derive(Debug, ToShmem)]
+/// A @-moz-document rule
+pub struct DocumentRule {
+    /// The parsed condition
+    pub condition: DocumentCondition,
+    /// Child rules
+    pub rules: Arc<Locked<CssRules>>,
+    /// The line and column of the rule's source code.
+    pub source_location: SourceLocation,
+}
+
+impl DocumentRule {
+    /// Measure heap usage.
+    #[cfg(feature = "gecko")]
+    pub fn size_of(&self, guard: &SharedRwLockReadGuard, ops: &mut MallocSizeOfOps) -> usize {
+        // Measurement of other fields may be added later.
+        self.rules.unconditional_shallow_size_of(ops) +
+            self.rules.read_with(guard).size_of(guard, ops)
+    }
+}
+
+impl ToCssWithGuard for DocumentRule {
+    fn to_css(&self, guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
+        dest.write_str("@-moz-document ")?;
+        self.condition.to_css(&mut CssWriter::new(dest))?;
+        dest.write_str(" {")?;
+        for rule in self.rules.read_with(guard).0.iter() {
+            dest.write_char(' ')?;
+            rule.to_css(guard, dest)?;
+        }
+        dest.write_str(" }")
+    }
+}
+
+impl DeepCloneWithLock for DocumentRule {
+    /// Deep clones this DocumentRule.
+    fn deep_clone_with_lock(
+        &self,
+        lock: &SharedRwLock,
+        guard: &SharedRwLockReadGuard,
+        params: &DeepCloneParams,
+    ) -> Self {
+        let rules = self.rules.read_with(guard);
+        DocumentRule {
+            condition: self.condition.clone(),
+            rules: Arc::new(lock.wrap(rules.deep_clone_with_lock(lock, guard, params))),
+            source_location: self.source_location.clone(),
+        }
+    }
+}
+
+/// The kind of media document that the rule will match.
+#[derive(Clone, Copy, Debug, Parse, PartialEq, ToCss, ToShmem)]
+#[allow(missing_docs)]
+pub enum MediaDocumentKind {
+    All,
+    Plugin,
+    Image,
+    Video,
+}
+
+/// A matching function for a `@document` rule's condition.
+#[derive(Clone, Debug, ToCss, ToShmem)]
+pub enum DocumentMatchingFunction {
+    /// Exact URL matching function. It evaluates to true whenever the
+    /// URL of the document being styled is exactly the URL given.
+    Url(CssUrl),
+    /// URL prefix matching function. It evaluates to true whenever the
+    /// URL of the document being styled has the argument to the
+    /// function as an initial substring (which is true when the two
+    /// strings are equal). When the argument is the empty string,
+    /// it evaluates to true for all documents.
+    #[css(function)]
+    UrlPrefix(String),
+    /// Domain matching function. It evaluates to true whenever the URL
+    /// of the document being styled has a host subcomponent and that
+    /// host subcomponent is exactly the argument to the ‘domain()’
+    /// function or a final substring of the host component is a
+    /// period (U+002E) immediately followed by the argument to the
+    /// ‘domain()’ function.
+    #[css(function)]
+    Domain(String),
+    /// Regular expression matching function. It evaluates to true
+    /// whenever the regular expression matches the entirety of the URL
+    /// of the document being styled.
+    #[css(function)]
+    Regexp(String),
+    /// Matching function for a media document.
+    #[css(function)]
+    MediaDocument(MediaDocumentKind),
+    /// Matching function for a plain-text document.
+    #[css(function)]
+    PlainTextDocument(()),
+    /// Matching function for a document that can be observed by other content
+    /// documents.
+    #[css(function)]
+    UnobservableDocument(()),
+}
+
+macro_rules! parse_quoted_or_unquoted_string {
+    ($input:ident, $url_matching_function:expr) => {
+        $input.parse_nested_block(|input| {
+            let start = input.position();
+            input
+                .parse_entirely(|input| {
+                    let string = input.expect_string()?;
+                    Ok($url_matching_function(string.as_ref().to_owned()))
+                })
+                .or_else(|_: ParseError| {
+                    while let Ok(_) = input.next() {}
+                    Ok($url_matching_function(input.slice_from(start).to_string()))
+                })
+        })
+    };
+}
+
+impl DocumentMatchingFunction {
+    /// Parse a URL matching function for a`@document` rule's condition.
+    pub fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        if let Ok(url) = input.try_parse(|input| CssUrl::parse(context, input)) {
+            return Ok(DocumentMatchingFunction::Url(url));
+        }
+
+        let location = input.current_source_location();
+        let function = input.expect_function()?.clone();
+        match_ignore_ascii_case! { &function,
+            "url-prefix" => {
+                parse_quoted_or_unquoted_string!(input, DocumentMatchingFunction::UrlPrefix)
+            },
+            "domain" => {
+                parse_quoted_or_unquoted_string!(input, DocumentMatchingFunction::Domain)
+            },
+            "regexp" => {
+                input.parse_nested_block(|input| {
+                    Ok(DocumentMatchingFunction::Regexp(
+                        input.expect_string()?.as_ref().to_owned(),
+                    ))
+                })
+            },
+            "media-document" => {
+                input.parse_nested_block(|input| {
+                    let kind = MediaDocumentKind::parse(input)?;
+                    Ok(DocumentMatchingFunction::MediaDocument(kind))
+                })
+            },
+
+            "plain-text-document" => {
+                input.parse_nested_block(|input| {
+                    input.expect_exhausted()?;
+                    Ok(DocumentMatchingFunction::PlainTextDocument(()))
+                })
+            },
+
+            "unobservable-document" => {
+                input.parse_nested_block(|input| {
+                    input.expect_exhausted()?;
+                    Ok(DocumentMatchingFunction::UnobservableDocument(()))
+                })
+            },
+
+            _ => {
+                Err(location.new_custom_error(
+                    StyleParseErrorKind::UnexpectedFunction(function.clone())
+                ))
+            },
+        }
+    }
+
+    #[cfg(feature = "gecko")]
+    /// Evaluate a URL matching function.
+    pub fn evaluate(&self, device: &Device) -> bool {
+        use crate::gecko_bindings::bindings::Gecko_DocumentRule_UseForPresentation;
+        use crate::gecko_bindings::structs::DocumentMatchingFunction as GeckoDocumentMatchingFunction;
+        use nsstring::nsCStr;
+
+        let func = match *self {
+            DocumentMatchingFunction::Url(_) => GeckoDocumentMatchingFunction::URL,
+            DocumentMatchingFunction::UrlPrefix(_) => GeckoDocumentMatchingFunction::URLPrefix,
+            DocumentMatchingFunction::Domain(_) => GeckoDocumentMatchingFunction::Domain,
+            DocumentMatchingFunction::Regexp(_) => GeckoDocumentMatchingFunction::RegExp,
+            DocumentMatchingFunction::MediaDocument(_) => {
+                GeckoDocumentMatchingFunction::MediaDocument
+            },
+            DocumentMatchingFunction::PlainTextDocument(..) => {
+                GeckoDocumentMatchingFunction::PlainTextDocument
+            },
+            DocumentMatchingFunction::UnobservableDocument(..) => {
+                GeckoDocumentMatchingFunction::UnobservableDocument
+            },
+        };
+
+        let pattern = nsCStr::from(match *self {
+            DocumentMatchingFunction::Url(ref url) => url.as_str(),
+            DocumentMatchingFunction::UrlPrefix(ref pat) |
+            DocumentMatchingFunction::Domain(ref pat) |
+            DocumentMatchingFunction::Regexp(ref pat) => pat,
+            DocumentMatchingFunction::MediaDocument(kind) => match kind {
+                MediaDocumentKind::All => "all",
+                MediaDocumentKind::Image => "image",
+                MediaDocumentKind::Plugin => "plugin",
+                MediaDocumentKind::Video => "video",
+            },
+            DocumentMatchingFunction::PlainTextDocument(()) |
+            DocumentMatchingFunction::UnobservableDocument(()) => "",
+        });
+        unsafe { Gecko_DocumentRule_UseForPresentation(device.document(), &*pattern, func) }
+    }
+
+    #[cfg(not(feature = "gecko"))]
+    /// Evaluate a URL matching function.
+    pub fn evaluate(&self, _: &Device) -> bool {
+        false
+    }
+}
+
+/// A `@document` rule's condition.
+///
+/// <https://www.w3.org/TR/2012/WD-css3-conditional-20120911/#at-document>
+///
+/// The `@document` rule's condition is written as a comma-separated list of
+/// URL matching functions, and the condition evaluates to true whenever any
+/// one of those functions evaluates to true.
+#[derive(Clone, Debug, ToCss, ToShmem)]
+#[css(comma)]
+pub struct DocumentCondition(#[css(iterable)] Vec<DocumentMatchingFunction>);
+
+impl DocumentCondition {
+    /// Parse a document condition.
+    pub fn parse<'i, 't>(
+        context: &ParserContext,
+        input: &mut Parser<'i, 't>,
+    ) -> Result<Self, ParseError<'i>> {
+        let conditions =
+            input.parse_comma_separated(|input| DocumentMatchingFunction::parse(context, input))?;
+
+        let condition = DocumentCondition(conditions);
+        if !condition.allowed_in(context) {
+            return Err(input.new_error(BasicParseErrorKind::AtRuleInvalid("-moz-document".into())));
+        }
+        Ok(condition)
+    }
+
+    /// Evaluate a document condition.
+    pub fn evaluate(&self, device: &Device) -> bool {
+        self.0
+            .iter()
+            .any(|url_matching_function| url_matching_function.evaluate(device))
+    }
+
+    #[cfg(feature = "servo")]
+    fn allowed_in(&self, _: &ParserContext) -> bool {
+        false
+    }
+
+    #[cfg(feature = "gecko")]
+    fn allowed_in(&self, context: &ParserContext) -> bool {
+        use static_prefs::pref;
+
+        if context.in_ua_or_chrome_sheet() {
+            return true;
+        }
+
+        if pref!("layout.css.moz-document.content.enabled") {
+            return true;
+        }
+
+        // Allow a single url-prefix() for compatibility.
+        //
+        // See bug 1446470 and dependencies.
+        if self.0.len() != 1 {
+            return false;
+        }
+
+        // NOTE(emilio): This technically allows url-prefix("") too, but...
+        match self.0[0] {
+            DocumentMatchingFunction::UrlPrefix(ref prefix) => prefix.is_empty(),
+            _ => false,
+        }
+    }
+}