From f173504ded726ddecf7a92f1864ba6e9662d9eae Mon Sep 17 00:00:00 2001
From: Till Schneidereit <till@tillschneidereit.net>
Date: Mon, 5 Oct 2015 15:49:26 +0200
Subject: [PATCH] Make UA and user stylesheets static and shared by all Stylist
 instances

---
 components/layout/layout_task.rs      |  6 +--
 components/style/selector_matching.rs | 57 +++++++++++++++------------
 2 files changed, 35 insertions(+), 28 deletions(-)

diff --git a/components/layout/layout_task.rs b/components/layout/layout_task.rs
index d4931848f05f..cb3fe04eb571 100644
--- a/components/layout/layout_task.rs
+++ b/components/layout/layout_task.rs
@@ -75,7 +75,7 @@ use style::computed_values::{self, filter, mix_blend_mode};
 use style::media_queries::{Device, MediaQueryList, MediaType};
 use style::properties::longhands::{display, position};
 use style::properties::style_structs;
-use style::selector_matching::Stylist;
+use style::selector_matching::{Stylist, USER_OR_USER_AGENT_STYLESHEETS};
 use style::stylesheets::{CSSRule, CSSRuleIteratorExt, Origin, Stylesheet};
 use style::values::AuExtensionMethods;
 use style::viewport::ViewportRule;
@@ -377,8 +377,8 @@ impl LayoutTask {
 
         let stylist = box Stylist::new(device);
         let outstanding_web_fonts_counter = Arc::new(AtomicUsize::new(0));
-        for user_or_user_agent_stylesheet in stylist.stylesheets() {
-            add_font_face_rules(user_or_user_agent_stylesheet,
+        for stylesheet in &*USER_OR_USER_AGENT_STYLESHEETS {
+            add_font_face_rules(stylesheet,
                                 &stylist.device,
                                 &font_cache_task,
                                 &font_cache_sender,
diff --git a/components/style/selector_matching.rs b/components/style/selector_matching.rs
index 53f1a0d35895..4ceedb1f51e2 100644
--- a/components/style/selector_matching.rs
+++ b/components/style/selector_matching.rs
@@ -26,6 +26,36 @@ use viewport::{MaybeNew, ViewportRuleCascade};
 pub type DeclarationBlock = GenericDeclarationBlock<Vec<PropertyDeclaration>>;
 
 
+lazy_static! {
+    pub static ref USER_OR_USER_AGENT_STYLESHEETS: Vec<Stylesheet> = {
+        let mut stylesheets = vec!();
+        // FIXME: presentational-hints.css should be at author origin with zero specificity.
+        //        (Does it make a difference?)
+        for &filename in &["user-agent.css", "servo.css", "presentational-hints.css"] {
+            match read_resource_file(&[filename]) {
+                Ok(res) => {
+                    let ua_stylesheet = Stylesheet::from_bytes(
+                        &res,
+                        Url::parse(&format!("chrome:///{:?}", filename)).unwrap(),
+                        None,
+                        None,
+                        Origin::UserAgent);
+                    stylesheets.push(ua_stylesheet);
+                }
+                Err(..) => {
+                    error!("Failed to load UA stylesheet {}!", filename);
+                    process::exit(1);
+                }
+            }
+        }
+        for &(ref contents, ref url) in &opts::get().user_stylesheets {
+            stylesheets.push(Stylesheet::from_bytes(
+                &contents, url.clone(), None, None, Origin::User));
+        }
+        stylesheets
+    };
+}
+
 pub struct Stylist {
     // List of stylesheets (including all media rules)
     stylesheets: Vec<Stylesheet>,
@@ -51,7 +81,7 @@ pub struct Stylist {
 impl Stylist {
     #[inline]
     pub fn new(device: Device) -> Stylist {
-        let mut stylist = Stylist {
+        let stylist = Stylist {
             stylesheets: vec!(),
             device: device,
             is_dirty: true,
@@ -63,29 +93,6 @@ impl Stylist {
             state_deps: StateDependencySet::new(),
         };
         // FIXME: Add iso-8859-9.css when the document’s encoding is ISO-8859-8.
-        // FIXME: presentational-hints.css should be at author origin with zero specificity.
-        //        (Does it make a difference?)
-        for &filename in &["user-agent.css", "servo.css", "presentational-hints.css"] {
-            match read_resource_file(&[filename]) {
-                Ok(res) => {
-                    let ua_stylesheet = Stylesheet::from_bytes(
-                        &res,
-                        Url::parse(&format!("chrome:///{:?}", filename)).unwrap(),
-                        None,
-                        None,
-                        Origin::UserAgent);
-                    stylist.add_stylesheet(ua_stylesheet);
-                }
-                Err(..) => {
-                    error!("Stylist::new() failed at loading {}!", filename);
-                    process::exit(1);
-                }
-            }
-        }
-        for &(ref contents, ref url) in &opts::get().user_stylesheets {
-            stylist.add_stylesheet(Stylesheet::from_bytes(
-                &contents, url.clone(), None, None, Origin::User));
-        }
         stylist
     }
 
@@ -110,7 +117,7 @@ impl Stylist {
             self.rules_source_order = 0;
             self.state_deps.clear();
 
-            for stylesheet in &self.stylesheets {
+            for stylesheet in USER_OR_USER_AGENT_STYLESHEETS.iter().chain(&self.stylesheets) {
                 let (mut element_map, mut before_map, mut after_map) = match stylesheet.origin {
                     Origin::UserAgent => (
                         &mut self.element_map.user_agent,