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return primitive types, delegate stylesheet creation past FFI
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@antonok-edm
antonok-edm committed Nov 18, 2019
1 parent 1ee60d6 commit a3a20d0
Showing 1 changed file with 38 additions and 121 deletions.
159 changes: 38 additions & 121 deletions src/cosmetic_filter_cache.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -4,8 +4,6 @@ use crate::resources::{Resource, ScriptletResourceStorage};
use crate::utils::Hash;

use std::collections::{HashSet, HashMap};
use std::cell::RefCell;
use std::sync::Mutex;

use serde::{Deserialize, Serialize};
use psl::Psl;
Expand All @@ -14,65 +12,46 @@ lazy_static! {
static ref PUBLIC_SUFFIXES: psl::List = psl::List::new();
}

fn generic_selectors_to_stylesheet<'a, I>(mut selectors: I) -> String
where
I: Iterator<Item = &'a String>,
{
if let Some(first_rule) = selectors.next() {
// Brave's generic rules in stylesheet format are about 30000 characters long
let mut stylesheet = String::with_capacity(32768);
stylesheet += &first_rule;

selectors.for_each(|rule| {
stylesheet += ",";
stylesheet += &rule;
});
stylesheet += "{display:none !important;}";

stylesheet
} else {
"".into()
}
}

#[derive(Debug, PartialEq, Eq)]
#[derive(Debug, PartialEq, Eq, Deserialize, Serialize)]
pub struct HostnameSpecificResources {
pub stylesheet: String,
pub hide_selectors: HashSet<String>,
pub style_selectors: HashMap<String, Vec<String>>,
pub exceptions: HashSet<String>,
pub injected_script: String,
}

impl HostnameSpecificResources {
pub fn empty() -> Self {
Self {
stylesheet: String::new(),
hide_selectors: HashSet::new(),
style_selectors: HashMap::new(),
exceptions: HashSet::new(),
injected_script: String::new(),
}
}
}

fn specific_rules_to_stylesheet(rules: &[&SpecificFilterType]) -> (String, Vec<String>) {
fn hostname_specific_rules(rules: &[&SpecificFilterType]) -> (HashSet<String>, HashMap<String, Vec<String>>, Vec<String>) {
if rules.is_empty() {
("".into(), vec![])
(HashSet::default(), HashMap::default(), vec![])
} else {
let mut script_rules = Vec::with_capacity(10);

let mut hide_stylesheet = String::with_capacity(100 * rules.len());
let mut styled_stylesheet = String::with_capacity(10 * rules.len());
let mut hide_rules = HashSet::with_capacity(rules.len());
let mut style_rules: HashMap<String, Vec<String>> = HashMap::with_capacity(rules.len());

rules.iter()
.for_each(|rule| {
match rule {
SpecificFilterType::Hide(sel) => {
hide_stylesheet += sel;
hide_stylesheet += ",";
hide_rules.insert(sel.to_owned());
}
SpecificFilterType::Style(sel, style) => {
styled_stylesheet += sel;
styled_stylesheet += "{";
styled_stylesheet += style;
styled_stylesheet += "}\n";
if let Some(entry) = style_rules.get_mut(sel) {
entry.push(style.to_owned());
} else {
style_rules.insert(sel.to_owned(), vec![style.to_owned()]);
}
}
SpecificFilterType::ScriptInject(sel) => {
script_rules.push(sel.to_owned());
Expand All @@ -81,13 +60,7 @@ fn specific_rules_to_stylesheet(rules: &[&SpecificFilterType]) -> (String, Vec<S
}
});

if let Some(_trailing_comma) = hide_stylesheet.pop() {
hide_stylesheet += "{display:none !important;}\n";
}

hide_stylesheet += &styled_stylesheet;

(hide_stylesheet, script_rules)
(hide_rules, style_rules, script_rules)
}
}

Expand All @@ -101,11 +74,6 @@ pub struct CosmeticFilterCache {
specific_rules: HostnameRuleDb,

misc_generic_selectors: HashSet<String>,
// The base stylesheet can be invalidated if a new miscellaneous rule is added. RefCell is used
// to regenerate and cache the base stylesheet behind an immutable reference if necessary.
// Mutex is used to ensure thread-safety in the event that multiple FFI accesses occur
// simultaneously.
base_stylesheet: Mutex<RefCell<Option<String>>>,

scriptlets: ScriptletResourceStorage,
}
Expand All @@ -121,7 +89,6 @@ impl CosmeticFilterCache {
specific_rules: HostnameRuleDb::new(),

misc_generic_selectors: HashSet::with_capacity(rules.len() / 30),
base_stylesheet: Mutex::new(RefCell::new(None)),

scriptlets: Default::default(),
};
Expand All @@ -130,22 +97,9 @@ impl CosmeticFilterCache {
self_.add_filter(rule)
}

self_.regen_base_stylesheet();

self_
}

/// Rebuilds and caches the base stylesheet if necessary.
/// This operation can be done for free if the stylesheet has not already been invalidated.
fn regen_base_stylesheet(&self) {
// `expect` should not fail unless a thread holding the locked mutex panics
let base_stylesheet = self.base_stylesheet.lock().expect("Acquire base_stylesheet mutex");
if base_stylesheet.borrow().is_none() {
let stylesheet = generic_selectors_to_stylesheet(self.misc_generic_selectors.iter());
base_stylesheet.replace(Some(stylesheet));
}
}

pub fn add_filter(&mut self, rule: CosmeticFilter) {
if rule.has_hostname_constraint() {
if let Some(generic_rule) = rule.hidden_generic_rule() {
Expand Down Expand Up @@ -187,8 +141,6 @@ impl CosmeticFilterCache {
}
} else {
self.misc_generic_selectors.insert(rule.selector);
// `expect` should not fail unless a thread holding the locked mutex panics
self.base_stylesheet.lock().expect("acquire base_stylesheet mutex").replace(None);
}
}

Expand Down Expand Up @@ -261,16 +213,10 @@ impl CosmeticFilterCache {
exceptions.allow_specific_rule(r)
}).collect::<Vec<_>>();

// TODO some rules in the base_stylesheet could be overridden by hostname exceptions
let (hostname_stylesheet, script_injections) = specific_rules_to_stylesheet(&rules_that_apply[..]);

let mut base_stylesheet = if exceptions.hide_exceptions.is_empty() {
self.base_stylesheet()
} else {
generic_selectors_to_stylesheet(self.misc_generic_selectors.difference(&exceptions.hide_exceptions))
};
let (hostname_hide_selectors, style_selectors, script_injections) = hostname_specific_rules(&rules_that_apply[..]);

base_stylesheet += &hostname_stylesheet;
let mut hide_selectors = self.misc_generic_selectors.difference(&exceptions.hide_exceptions).cloned().collect::<HashSet<_>>();
hostname_hide_selectors.into_iter().for_each(|sel| { hide_selectors.insert(sel); });

let mut injected_script = String::new();
script_injections.iter().for_each(|s| {
Expand All @@ -281,25 +227,13 @@ impl CosmeticFilterCache {
});

HostnameSpecificResources {
stylesheet: base_stylesheet,
hide_selectors,
style_selectors,
exceptions: exceptions.hide_exceptions,
injected_script,
}
}

fn base_stylesheet(&self) -> String {
self.regen_base_stylesheet();
self.base_stylesheet
.lock()
// `expect` should not fail unless a thread holding the locked mutex panics
.expect("Acquire base_stylesheet mutex")
.borrow()
.as_ref()
// Unwrap is safe because the stylesheet is regenerated above if it is None
.unwrap()
.clone()
}

pub fn use_resources(&mut self, resources: &[Resource]) {
self.scriptlets = ScriptletResourceStorage::from_resources(resources);
}
Expand Down Expand Up @@ -526,7 +460,7 @@ mod cosmetic_cache_tests {
assert_eq!(out, expected);

let out = cfcache.hostname_cosmetic_resources("example.com");
expected.stylesheet = ".item{display:none !important;}\n".into();
expected.hide_selectors.insert(".item".to_owned());
assert_eq!(out, expected);

let out = cfcache.hostname_cosmetic_resources("sub.example.com");
Expand All @@ -552,15 +486,17 @@ mod cosmetic_cache_tests {
assert_eq!(out, expected);

let out = cfcache.hostname_cosmetic_resources("a1.sub.example.com");
expected.stylesheet = ".element{display:none !important;}\n".into();
expected.hide_selectors.insert(".element".to_owned());
assert_eq!(out, expected);

let out = cfcache.hostname_cosmetic_resources("test.example.com");
expected.stylesheet = ".element{background: #fff}\n".into();
expected.hide_selectors.clear();
expected.style_selectors.insert(".element".to_owned(), vec!["background: #fff".to_owned()]);
assert_eq!(out, expected);

let out = cfcache.hostname_cosmetic_resources("a2.sub.example.com");
expected.stylesheet = ".element{background: #000}\n".into();
expected.style_selectors.clear();
expected.style_selectors.insert(".element".to_owned(), vec!["background: #000".to_owned()]);
assert_eq!(out, expected);
}

Expand Down Expand Up @@ -625,25 +561,6 @@ mod cosmetic_cache_tests {
assert_eq!(out, expected);
}

#[test]
fn base_stylesheet() {
let cfcache = cache_from_rules(vec![
"##a[href=\"https://ads.com\"]",
"~test.com##div > p.ads",
"example.com,~sub.example.com##[href^=\"http://malware.ru\"]",
"###simple-generic",
"##.complex #generic",
]);

let out = cfcache.base_stylesheet();
assert!(out.contains("div > p.ads"));
assert!(out.contains("a[href=\"https://ads.com\"]"));
assert!(!out.contains("#simple-generic"));
assert!(!out.contains(".complex #generic"));
assert!(!out.contains("[href^=\"http://malware.ru\"]"));
assert!(out.ends_with("{display:none !important;}"));
}

#[test]
fn matching_class_id_stylesheet() {
let rules = vec![
Expand Down Expand Up @@ -726,16 +643,16 @@ mod cosmetic_cache_tests {
];
let cfcache = CosmeticFilterCache::new(rules.iter().map(|r| CosmeticFilter::parse(r, false).unwrap()).collect::<Vec<_>>());

let base_stylesheet = cfcache.hostname_cosmetic_resources("test.com").stylesheet;
assert!(base_stylesheet.contains("a[href=\"bad.com\"]"));
assert!(base_stylesheet.contains("div > p"));
assert!(base_stylesheet.contains("a[href=\"notbad.com\"]"));
assert!(base_stylesheet.ends_with("{display:none !important;}"));

let base_stylesheet = cfcache.hostname_cosmetic_resources("example.com").stylesheet;
assert!(base_stylesheet.contains("a[href=\"bad.com\"]"));
assert!(!base_stylesheet.contains("div > p"));
assert!(!base_stylesheet.contains("a[href=\"notbad.com\"]"));
assert!(base_stylesheet.ends_with("{display:none !important;}"));
let hide_selectors = cfcache.hostname_cosmetic_resources("test.com").hide_selectors;
let mut expected_hides = HashSet::new();
expected_hides.insert("a[href=\"bad.com\"]".to_owned());
expected_hides.insert("div > p".to_owned());
expected_hides.insert("a[href=\"notbad.com\"]".to_owned());
assert_eq!(hide_selectors, expected_hides);

let hide_selectors = cfcache.hostname_cosmetic_resources("example.com").hide_selectors;
let mut expected_hides = HashSet::new();
expected_hides.insert("a[href=\"bad.com\"]".to_owned());
assert_eq!(hide_selectors, expected_hides);
}
}

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