Return list of selectors instead of a full stylesheet

benches/bench_cosmetic_matching.rs

@@ -52,7 +52,7 @@ fn by_classes_ids(c: &mut Criterion) {
             let (_, cosmetic_filters) = parse_filters(&rules, false, true, false);
             let cfcache = CosmeticFilterCache::new(cosmetic_filters);
             let exceptions = Default::default();
-            b.iter(|| cfcache.class_id_stylesheet(&vec!["ad".to_owned()][..], &vec!["ad".to_owned()][..], &exceptions))
+            b.iter(|| cfcache.hidden_class_id_selectors(&vec!["ad".to_owned()][..], &vec!["ad".to_owned()][..], &exceptions))
         }).with_function("many lists", move |b| {
             let rules = rules_from_lists(&vec![
                 "data/easylist.to/easylist/easylist.txt".to_owned(),
@@ -63,7 +63,7 @@ fn by_classes_ids(c: &mut Criterion) {
             let (_, cosmetic_filters) = parse_filters(&rules, false, true, false);
             let cfcache = CosmeticFilterCache::new(cosmetic_filters);
             let exceptions = Default::default();
-            b.iter(|| cfcache.class_id_stylesheet(&vec!["ad".to_owned()][..], &vec!["ad".to_owned()][..], &exceptions))
+            b.iter(|| cfcache.hidden_class_id_selectors(&vec!["ad".to_owned()][..], &vec!["ad".to_owned()][..], &exceptions))
         }).with_function("many matching classes and ids", move |b| {
             let rules = rules_from_lists(&vec![
                 "data/easylist.to/easylist/easylist.txt".to_owned(),
@@ -104,7 +104,7 @@ fn by_classes_ids(c: &mut Criterion) {
                 "header".to_owned(),
                 "advertisingModule160x600".to_owned(),
             ];
-            b.iter(|| cfcache.class_id_stylesheet(&class_list[..], &id_list[..], &exceptions))
+            b.iter(|| cfcache.hidden_class_id_selectors(&class_list[..], &id_list[..], &exceptions))
         })
         .throughput(Throughput::Elements(1))
         .sample_size(20)

src/cosmetic_filter_cache.rs

@@ -157,7 +157,7 @@ impl CosmeticFilterCache {
         }
     }
 
-    pub fn class_id_stylesheet(&self, classes: &[String], ids: &[String], exceptions: &HashSet<String>) -> Option<String> {
+    pub fn hidden_class_id_selectors(&self, classes: &[String], ids: &[String], exceptions: &HashSet<String>) -> Vec<String> {
         let mut simple_classes = vec![];
         let mut simple_ids = vec![];
         let mut complex_selectors = vec![];
@@ -188,16 +188,13 @@ impl CosmeticFilterCache {
         });
 
         if simple_classes.is_empty() && simple_ids.is_empty() && complex_selectors.is_empty() {
-            return None;
+            return vec![];
         }
 
-        let stylesheet = simple_classes.into_iter().map(|class| format!(".{}", class))
+        simple_classes.into_iter().map(|class| format!(".{}", class))
             .chain(simple_ids.into_iter().map(|id| format!("#{}", id)))
             .chain(complex_selectors.into_iter().cloned())
             .collect::<Vec<_>>()
-            .join(",") + "{display:none !important;}";
-
-        Some(stylesheet)
     }
 
     pub fn hostname_cosmetic_resources(&self, hostname: &str) -> HostnameSpecificResources {
@@ -575,8 +572,8 @@ mod cosmetic_cache_tests {
     }
 
     #[test]
-    fn matching_class_id_stylesheet() {
-        let rules = vec![
+    fn matching_hidden_class_id_selectors() {
+        let rules = [
             "##.a-class",
             "###simple-id",
             "##.a-class .with .children",
@@ -585,29 +582,29 @@ mod cosmetic_cache_tests {
         ];
         let cfcache = CosmeticFilterCache::new(rules.iter().map(|r| CosmeticFilter::parse(r, false).unwrap()).collect::<Vec<_>>());
 
-        let out = cfcache.class_id_stylesheet(&vec!["with".into()], &vec![], &HashSet::default());
-        assert_eq!(out, None);
+        let out = cfcache.hidden_class_id_selectors(&["with".into()], &[], &HashSet::default());
+        assert_eq!(out, Vec::<String>::new());
 
-        let out = cfcache.class_id_stylesheet(&vec![], &vec!["with".into()], &HashSet::default());
-        assert_eq!(out, None);
+        let out = cfcache.hidden_class_id_selectors(&[], &["with".into()], &HashSet::default());
+        assert_eq!(out, Vec::<String>::new());
 
-        let out = cfcache.class_id_stylesheet(&vec![], &vec!["a-class".into()], &HashSet::default());
-        assert_eq!(out, None);
+        let out = cfcache.hidden_class_id_selectors(&[], &["a-class".into()], &HashSet::default());
+        assert_eq!(out, Vec::<String>::new());
 
-        let out = cfcache.class_id_stylesheet(&vec!["simple-id".into()], &vec![], &HashSet::default());
-        assert_eq!(out, None);
+        let out = cfcache.hidden_class_id_selectors(&["simple-id".into()], &[], &HashSet::default());
+        assert_eq!(out, Vec::<String>::new());
 
-        let out = cfcache.class_id_stylesheet(&vec!["a-class".into()], &vec![], &HashSet::default());
-        assert_eq!(out, Some(".a-class,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["a-class".into()], &[], &HashSet::default());
+        assert_eq!(out, [".a-class", ".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec!["children".into(), "a-class".into()], &vec![], &HashSet::default());
-        assert_eq!(out, Some(".a-class,.children .including #simple-id,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["children".into(), "a-class".into()], &[], &HashSet::default());
+        assert_eq!(out, [".a-class", ".children .including #simple-id", ".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec![], &vec!["simple-id".into()], &HashSet::default());
-        assert_eq!(out, Some("#simple-id{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&[], &["simple-id".into()], &HashSet::default());
+        assert_eq!(out, ["#simple-id"]);
 
-        let out = cfcache.class_id_stylesheet(&vec!["children".into(), "a-class".into()], &vec!["simple-id".into()], &HashSet::default());
-        assert_eq!(out, Some(".a-class,#simple-id,.children .including #simple-id,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["children".into(), "a-class".into()], &["simple-id".into()], &HashSet::default());
+        assert_eq!(out, [".a-class", "#simple-id", ".children .including #simple-id", ".a-class .with .children"]);
     }
 
     #[test]
@@ -624,25 +621,25 @@ mod cosmetic_cache_tests {
         let cfcache = CosmeticFilterCache::new(rules.iter().map(|r| CosmeticFilter::parse(r, false).unwrap()).collect::<Vec<_>>());
         let exceptions = cfcache.hostname_cosmetic_resources("example.co.uk").exceptions;
 
-        let out = cfcache.class_id_stylesheet(&vec!["a-class".into()], &vec![], &exceptions);
-        assert_eq!(out, Some(".a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["a-class".into()], &[], &exceptions);
+        assert_eq!(out, [".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec!["children".into(), "a-class".into()], &vec!["simple-id".into()], &exceptions);
-        assert_eq!(out, Some("#simple-id,.children .including #simple-id,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["children".into(), "a-class".into()], &["simple-id".into()], &exceptions);
+        assert_eq!(out, ["#simple-id", ".children .including #simple-id", ".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec![], &vec!["test-element".into()], &exceptions);
-        assert_eq!(out, Some("#test-element{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&[], &["test-element".into()], &exceptions);
+        assert_eq!(out, ["#test-element"]);
 
         let exceptions = cfcache.hostname_cosmetic_resources("a1.test.com").exceptions;
 
-        let out = cfcache.class_id_stylesheet(&vec!["a-class".into()], &vec![], &exceptions);
-        assert_eq!(out, Some(".a-class,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["a-class".into()], &[], &exceptions);
+        assert_eq!(out, [".a-class", ".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec!["children".into(), "a-class".into()], &vec!["simple-id".into()], &exceptions);
-        assert_eq!(out, Some(".a-class,#simple-id,.children .including #simple-id,.a-class .with .children{display:none !important;}".to_string()));
+        let out = cfcache.hidden_class_id_selectors(&["children".into(), "a-class".into()], &["simple-id".into()], &exceptions);
+        assert_eq!(out, [".a-class", "#simple-id", ".children .including #simple-id", ".a-class .with .children"]);
 
-        let out = cfcache.class_id_stylesheet(&vec![], &vec!["test-element".into()], &exceptions);
-        assert_eq!(out, None);
+        let out = cfcache.hidden_class_id_selectors(&[], &["test-element".into()], &exceptions);
+        assert_eq!(out, Vec::<String>::new());
     }
 
     #[test]

src/engine.rs

@@ -218,17 +218,18 @@ impl Engine {
     // Cosmetic filter functionality
 
     /// If any of the provided CSS classes or ids could cause a certain generic CSS hide rule
-    /// (i.e. `{ display: none !important; }`) to be required, this method will return a stylesheet
-    /// including it, providing that the corresponding rule does not have an exception.
+    /// (i.e. `{ display: none !important; }`) to be required, this method will return a list of
+    /// CSS selectors corresponding to rules referencing those classes or ids, provided that the
+    /// corresponding rules are not excepted.
     ///
     /// `exceptions` should be passed directly from `HostnameSpecificResources`.
-    pub fn class_id_stylesheet(&self, classes: &[String], ids: &[String], exceptions: &HashSet<String>) -> Option<String> {
-        self.cosmetic_cache.class_id_stylesheet(classes, ids, exceptions)
+    pub fn hidden_class_id_selectors(&self, classes: &[String], ids: &[String], exceptions: &HashSet<String>) -> Vec<String> {
+        self.cosmetic_cache.hidden_class_id_selectors(classes, ids, exceptions)
     }
 
     /// Returns a set of cosmetic filter resources required for a particular hostname. Once this
     /// has been called, all CSS ids and classes on a page should be passed to
-    /// `class_id_stylesheet` to obtain any stylesheets consisting of generic rules.
+    /// `hidden_class_id_selectors` to obtain any stylesheets consisting of generic rules.
     pub fn hostname_cosmetic_resources(&self, hostname: &str) -> HostnameSpecificResources {
         self.cosmetic_cache.hostname_cosmetic_resources(hostname)
     }