From 1621e0679e92d69bae37da1a30c268ee717bb7ca Mon Sep 17 00:00:00 2001
From: Anthony Ramine <n.oxyde@gmail.com>
Date: Sat, 21 May 2016 00:55:01 +0200
Subject: [PATCH 1/2] Do not create a channel for each source in
 add_font_face_rules

---
 components/layout/layout_thread.rs | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/components/layout/layout_thread.rs b/components/layout/layout_thread.rs
index 779a23fba82..2d98b96fdcb 100644
--- a/components/layout/layout_thread.rs
+++ b/components/layout/layout_thread.rs
@@ -357,19 +357,23 @@ fn add_font_face_rules(stylesheet: &Stylesheet,
                        font_cache_thread: &FontCacheThread,
                        font_cache_sender: &IpcSender<()>,
                        outstanding_web_fonts_counter: &Arc<AtomicUsize>) {
-    for font_face in stylesheet.effective_rules(&device).font_face() {
-        for source in &font_face.sources {
-            if opts::get().load_webfonts_synchronously {
-                let (sender, receiver) = ipc::channel().unwrap();
+    if opts::get().load_webfonts_synchronously {
+        let (sender, receiver) = ipc::channel().unwrap();
+        for font_face in stylesheet.effective_rules(&device).font_face() {
+            for source in &font_face.sources {
                 font_cache_thread.add_web_font(font_face.family.clone(),
-                                             (*source).clone(),
-                                             sender);
+                                              (*source).clone(),
+                                              sender.clone());
                 receiver.recv().unwrap();
-            } else {
+            }
+        }
+    } else {
+        for font_face in stylesheet.effective_rules(&device).font_face() {
+            for source in &font_face.sources {
                 outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst);
                 font_cache_thread.add_web_font(font_face.family.clone(),
-                                             (*source).clone(),
-                                             (*font_cache_sender).clone());
+                                              (*source).clone(),
+                                              (*font_cache_sender).clone());
             }
         }
     }

From 64b34d516215985827249529a4977522a0f6be8e Mon Sep 17 00:00:00 2001
From: Anthony Ramine <n.oxyde@gmail.com>
Date: Thu, 2 Jun 2016 22:27:55 +0200
Subject: [PATCH 2/2] Introduce FontFaceRules::effective_sources()

This avoids downloading fonts in formats we don't support.
---
 components/layout/layout_thread.rs |  4 ++--
 components/style/font_face.rs      | 32 ++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/components/layout/layout_thread.rs b/components/layout/layout_thread.rs
index 2d98b96fdcb..db0968775a5 100644
--- a/components/layout/layout_thread.rs
+++ b/components/layout/layout_thread.rs
@@ -360,7 +360,7 @@ fn add_font_face_rules(stylesheet: &Stylesheet,
     if opts::get().load_webfonts_synchronously {
         let (sender, receiver) = ipc::channel().unwrap();
         for font_face in stylesheet.effective_rules(&device).font_face() {
-            for source in &font_face.sources {
+            for source in font_face.effective_sources() {
                 font_cache_thread.add_web_font(font_face.family.clone(),
                                               (*source).clone(),
                                               sender.clone());
@@ -369,7 +369,7 @@ fn add_font_face_rules(stylesheet: &Stylesheet,
         }
     } else {
         for font_face in stylesheet.effective_rules(&device).font_face() {
-            for source in &font_face.sources {
+            for source in font_face.effective_sources() {
                 outstanding_web_fonts_counter.fetch_add(1, Ordering::SeqCst);
                 font_cache_thread.add_web_font(font_face.family.clone(),
                                               (*source).clone(),
diff --git a/components/style/font_face.rs b/components/style/font_face.rs
index d41daea2f50..6db70a86e25 100644
--- a/components/style/font_face.rs
+++ b/components/style/font_face.rs
@@ -6,6 +6,8 @@ use computed_values::font_family::FontFamily;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
 use parser::{ParserContext, log_css_error};
 use properties::longhands::font_family::parse_one_family;
+use std::iter;
+use std::slice;
 use url::Url;
 
 #[derive(Clone, Debug, HeapSizeOf, PartialEq, Eq, Deserialize, Serialize)]
@@ -58,6 +60,36 @@ pub fn parse_font_face_block(context: &ParserContext, input: &mut Parser)
     }
 }
 
+pub struct EffectiveSourcesIter<'a>(slice::Iter<'a, Source>);
+
+impl FontFaceRule {
+    /// Returns the list of effective sources for that font-face, that is the
+    /// sources which don't list any format hint, or the ones which list at
+    /// least "truetype" or "opentype".
+    pub fn effective_sources(&self) -> EffectiveSourcesIter {
+        EffectiveSourcesIter(self.sources.iter())
+    }
+}
+
+impl<'a> iter::Iterator for EffectiveSourcesIter<'a> {
+    type Item = &'a Source;
+    fn next(&mut self) -> Option<&'a Source> {
+        self.0.find(|source| {
+            if let Source::Url(ref url_source) = **source {
+                let hints = &url_source.format_hints;
+                // We support only opentype fonts and truetype is an alias for
+                // that format. Sources without format hints need to be
+                // downloaded in case we support them.
+                hints.is_empty() || hints.iter().any(|hint| {
+                    hint == "truetype" || hint == "opentype" || hint == "woff"
+                })
+            } else {
+                true
+            }
+        })
+    }
+}
+
 enum FontFaceDescriptorDeclaration {
     Family(FontFamily),
     Src(Vec<Source>),