ublock-origin/src/js/cosmetic-filtering.js

988 lines
33 KiB
JavaScript

/*******************************************************************************
uBlock Origin - a browser extension to block requests.
Copyright (C) 2014-present Raymond Hill
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see {http://www.gnu.org/licenses/}.
Home: https://github.com/gorhill/uBlock
*/
'use strict';
/******************************************************************************/
import './utils.js';
import logger from './logger.js';
import µb from './background.js';
import { StaticExtFilteringHostnameDB } from './static-ext-filtering-db.js';
/******************************************************************************/
/******************************************************************************/
const SelectorCacheEntry = class {
constructor() {
this.reset();
}
reset() {
this.cosmetic = new Set();
this.cosmeticHashes = new Set();
this.disableSurveyor = false;
this.net = new Map();
this.accessId = SelectorCacheEntry.accessId++;
return this;
}
dispose() {
this.cosmetic = this.cosmeticHashes = this.net = null;
if ( SelectorCacheEntry.junkyard.length < 25 ) {
SelectorCacheEntry.junkyard.push(this);
}
}
addCosmetic(details) {
const selectors = details.selectors.join(',\n');
if ( selectors.length !== 0 ) {
this.cosmetic.add(selectors);
}
for ( const hash of details.hashes ) {
this.cosmeticHashes.add(hash);
}
}
addNet(selectors) {
if ( typeof selectors === 'string' ) {
this.net.set(selectors, this.accessId);
} else {
this.net.set(selectors.join(',\n'), this.accessId);
}
// Net request-derived selectors: I limit the number of cached
// selectors, as I expect cases where the blocked network requests
// are never the exact same URL.
if ( this.net.size < SelectorCacheEntry.netHighWaterMark ) { return; }
const keys = Array.from(this.net)
.sort((a, b) => b[1] - a[1])
.slice(SelectorCacheEntry.netLowWaterMark)
.map(a => a[0]);
for ( const key of keys ) {
this.net.delete(key);
}
}
addNetOne(selector, token) {
this.net.set(selector, token);
}
add(details) {
this.accessId = SelectorCacheEntry.accessId++;
if ( details.type === 'cosmetic' ) {
this.addCosmetic(details);
} else {
this.addNet(details.selectors);
}
}
// https://github.com/chrisaljoudi/uBlock/issues/420
remove(type) {
this.accessId = SelectorCacheEntry.accessId++;
if ( type === undefined || type === 'cosmetic' ) {
this.cosmetic.clear();
}
if ( type === undefined || type === 'net' ) {
this.net.clear();
}
}
retrieveToArray(iterator, out) {
for ( const selector of iterator ) {
out.push(selector);
}
}
retrieveToSet(iterator, out) {
for ( const selector of iterator ) {
out.add(selector);
}
}
retrieveNet(out) {
this.accessId = SelectorCacheEntry.accessId++;
if ( this.net.size === 0 ) { return false; }
this.retrieveToArray(this.net.keys(), out);
return true;
}
retrieveCosmetic(selectors, hashes) {
this.accessId = SelectorCacheEntry.accessId++;
if ( this.cosmetic.size === 0 ) { return false; }
this.retrieveToSet(this.cosmetic, selectors);
this.retrieveToArray(this.cosmeticHashes, hashes);
return true;
}
static factory() {
const entry = SelectorCacheEntry.junkyard.pop();
return entry
? entry.reset()
: new SelectorCacheEntry();
}
};
SelectorCacheEntry.accessId = 1;
SelectorCacheEntry.netLowWaterMark = 20;
SelectorCacheEntry.netHighWaterMark = 30;
SelectorCacheEntry.junkyard = [];
/******************************************************************************/
/******************************************************************************/
// http://www.cse.yorku.ca/~oz/hash.html#djb2
// Must mirror content script surveyor's version
const hashFromStr = (type, s) => {
const len = s.length;
const step = len + 7 >>> 3;
let hash = (type << 5) + type ^ len;
for ( let i = 0; i < len; i += step ) {
hash = (hash << 5) + hash ^ s.charCodeAt(i);
}
return hash & 0xFFFFFF;
};
// https://github.com/gorhill/uBlock/issues/1668
// The key must be literal: unescape escaped CSS before extracting key.
// It's an uncommon case, so it's best to unescape only when needed.
const keyFromSelector = selector => {
let key = '';
let matches = rePlainSelector.exec(selector);
if ( matches !== null ) {
key = matches[0];
} else {
matches = rePlainSelectorEx.exec(selector);
if ( matches === null ) { return; }
key = matches[1] || matches[2];
}
if ( key.includes('\\') === false ) { return key; }
matches = rePlainSelectorEscaped.exec(selector);
if ( matches === null ) { return; }
key = '';
const escaped = matches[0];
let beg = 0;
reEscapeSequence.lastIndex = 0;
for (;;) {
matches = reEscapeSequence.exec(escaped);
if ( matches === null ) {
return key + escaped.slice(beg);
}
key += escaped.slice(beg, matches.index);
beg = reEscapeSequence.lastIndex;
if ( matches[1].length === 1 ) {
key += matches[1];
} else {
key += String.fromCharCode(parseInt(matches[1], 16));
}
}
};
const rePlainSelector = /^[#.][\w\\-]+/;
const rePlainSelectorEx = /^[^#.\[(]+([#.][\w-]+)|([#.][\w-]+)$/;
const rePlainSelectorEscaped = /^[#.](?:\\[0-9A-Fa-f]+ |\\.|\w|-)+/;
const reEscapeSequence = /\\([0-9A-Fa-f]+ |.)/g;
/******************************************************************************/
/******************************************************************************/
// Cosmetic filter family tree:
//
// Generic
// Low generic simple: class or id only
// Low generic complex: class or id + extra stuff after
// High generic:
// High-low generic: [alt="..."],[title="..."]
// High-medium generic: [href^="..."]
// High-high generic: everything else
// Specific
// Specific hostname
// Specific entity
// Generic filters can only be enforced once the main document is loaded.
// Specific filers can be enforced before the main document is loaded.
const FilterContainer = function() {
this.reSimpleHighGeneric = /^(?:[a-z]*\[[^\]]+\]|\S+)$/;
this.selectorCache = new Map();
this.selectorCachePruneDelay = 10 * 60 * 1000; // 10 minutes
this.selectorCacheCountMin = 40;
this.selectorCacheCountMax = 50;
this.selectorCacheTimer = null;
// specific filters
this.specificFilters = new StaticExtFilteringHostnameDB(2);
// low generic cosmetic filters: map of hash => stringified selector list
this.lowlyGeneric = new Map();
// highly generic selectors sets
this.highlyGeneric = Object.create(null);
this.highlyGeneric.simple = {
canonical: 'highGenericHideSimple',
dict: new Set(),
str: '',
mru: new µb.MRUCache(16)
};
this.highlyGeneric.complex = {
canonical: 'highGenericHideComplex',
dict: new Set(),
str: '',
mru: new µb.MRUCache(16)
};
// Short-lived: content is valid only during one function call. These
// is to prevent repeated allocation/deallocation overheads -- the
// constructors/destructors of javascript Set/Map is assumed to be costlier
// than just calling clear() on these.
this.$specificSet = new Set();
this.$exceptionSet = new Set();
this.$proceduralSet = new Set();
this.$dummySet = new Set();
this.reset();
};
/******************************************************************************/
// Reset all, thus reducing to a minimum memory footprint of the context.
FilterContainer.prototype.reset = function() {
this.frozen = false;
this.acceptedCount = 0;
this.discardedCount = 0;
this.duplicateBuster = new Set();
this.selectorCache.clear();
if ( this.selectorCacheTimer !== null ) {
clearTimeout(this.selectorCacheTimer);
this.selectorCacheTimer = null;
}
// hostname, entity-based filters
this.specificFilters.clear();
// low generic cosmetic filters
this.lowlyGeneric.clear();
// highly generic selectors sets
this.highlyGeneric.simple.dict.clear();
this.highlyGeneric.simple.str = '';
this.highlyGeneric.simple.mru.reset();
this.highlyGeneric.complex.dict.clear();
this.highlyGeneric.complex.str = '';
this.highlyGeneric.complex.mru.reset();
this.selfieVersion = 1;
};
/******************************************************************************/
FilterContainer.prototype.freeze = function() {
this.duplicateBuster.clear();
this.specificFilters.collectGarbage();
this.highlyGeneric.simple.str = Array.from(this.highlyGeneric.simple.dict).join(',\n');
this.highlyGeneric.simple.mru.reset();
this.highlyGeneric.complex.str = Array.from(this.highlyGeneric.complex.dict).join(',\n');
this.highlyGeneric.complex.mru.reset();
this.frozen = true;
};
/******************************************************************************/
FilterContainer.prototype.compile = function(parser, writer) {
if ( parser.hasOptions() === false ) {
this.compileGenericSelector(parser, writer);
return true;
}
// https://github.com/chrisaljoudi/uBlock/issues/151
// Negated hostname means the filter applies to all non-negated hostnames
// of same filter OR globally if there is no non-negated hostnames.
let applyGlobally = true;
for ( const { hn, not, bad } of parser.getExtFilterDomainIterator() ) {
if ( bad ) { continue; }
if ( not === false ) {
applyGlobally = false;
}
this.compileSpecificSelector(parser, hn, not, writer);
}
if ( applyGlobally ) {
this.compileGenericSelector(parser, writer);
}
return true;
};
/******************************************************************************/
FilterContainer.prototype.compileGenericSelector = function(parser, writer) {
if ( parser.isException() ) {
this.compileGenericUnhideSelector(parser, writer);
} else {
this.compileGenericHideSelector(parser, writer);
}
};
/******************************************************************************/
FilterContainer.prototype.compileGenericHideSelector = function(
parser,
writer
) {
const { raw, compiled } = parser.result;
if ( compiled === undefined ) {
const who = writer.properties.get('name') || '?';
logger.writeOne({
realm: 'message',
type: 'error',
text: `Invalid generic cosmetic filter in ${who}: ${raw}`
});
return;
}
writer.select('COSMETIC_FILTERS:GENERIC');
// https://github.com/uBlockOrigin/uBlock-issues/issues/131
// Support generic procedural filters as per advanced settings.
if ( compiled.charCodeAt(0) === 0x7B /* '{' */ ) {
if ( µb.hiddenSettings.allowGenericProceduralFilters === true ) {
return this.compileSpecificSelector(parser, '', false, writer);
}
const who = writer.properties.get('name') || '?';
logger.writeOne({
realm: 'message',
type: 'error',
text: `Invalid generic cosmetic filter in ${who}: ##${raw}`
});
return;
}
const key = keyFromSelector(compiled);
if ( key !== undefined ) {
writer.push([
0,
hashFromStr(key.charCodeAt(0), key.slice(1)),
compiled,
]);
return;
}
// Pass this point, we are dealing with highly-generic cosmetic filters.
//
// For efficiency purpose, we will distinguish between simple and complex
// selectors.
if ( this.reSimpleHighGeneric.test(compiled) ) {
writer.push([ 4 /* simple */, compiled ]);
} else {
writer.push([ 5 /* complex */, compiled ]);
}
};
/******************************************************************************/
FilterContainer.prototype.compileGenericUnhideSelector = function(
parser,
writer
) {
// Procedural cosmetic filters are acceptable as generic exception filters.
const { raw, compiled } = parser.result;
if ( compiled === undefined ) {
const who = writer.properties.get('name') || '?';
logger.writeOne({
realm: 'message',
type: 'error',
text: `Invalid cosmetic filter in ${who}: #@#${raw}`
});
return;
}
writer.select('COSMETIC_FILTERS:SPECIFIC');
// https://github.com/chrisaljoudi/uBlock/issues/497
// All generic exception filters are stored as hostname-based filter
// whereas the hostname is the empty string (which matches all
// hostnames). No distinction is made between declarative and
// procedural selectors, since they really exist only to cancel
// out other cosmetic filters.
writer.push([ 8, '', 0b001, compiled ]);
};
/******************************************************************************/
FilterContainer.prototype.compileSpecificSelector = function(
parser,
hostname,
not,
writer
) {
const { raw, compiled, exception } = parser.result;
if ( compiled === undefined ) {
const who = writer.properties.get('name') || '?';
logger.writeOne({
realm: 'message',
type: 'error',
text: `Invalid cosmetic filter in ${who}: ##${raw}`
});
return;
}
writer.select('COSMETIC_FILTERS:SPECIFIC');
// https://github.com/chrisaljoudi/uBlock/issues/145
let unhide = exception ? 1 : 0;
if ( not ) { unhide ^= 1; }
let kind = 0;
if ( unhide === 1 ) {
kind |= 0b001; // Exception
}
if ( compiled.charCodeAt(0) === 0x7B /* '{' */ ) {
kind |= 0b010; // Procedural
}
if ( hostname === '*' ) {
kind |= 0b100; // Applies everywhere
}
writer.push([ 8, hostname, kind, compiled ]);
};
/******************************************************************************/
FilterContainer.prototype.fromCompiledContent = function(reader, options) {
if ( options.skipCosmetic ) {
this.skipCompiledContent(reader, 'SPECIFIC');
this.skipCompiledContent(reader, 'GENERIC');
return;
}
// Specific cosmetic filter section
reader.select('COSMETIC_FILTERS:SPECIFIC');
while ( reader.next() ) {
this.acceptedCount += 1;
const fingerprint = reader.fingerprint();
if ( this.duplicateBuster.has(fingerprint) ) {
this.discardedCount += 1;
continue;
}
this.duplicateBuster.add(fingerprint);
const args = reader.args();
switch ( args[0] ) {
// hash, example.com, .promoted-tweet
// hash, example.*, .promoted-tweet
//
// https://github.com/uBlockOrigin/uBlock-issues/issues/803
// Handle specific filters meant to apply everywhere, i.e. selectors
// not to be injected conditionally through the DOM surveyor.
// hash, *, .promoted-tweet
case 8:
if ( args[2] === 0b100 ) {
if ( this.reSimpleHighGeneric.test(args[3]) )
this.highlyGeneric.simple.dict.add(args[3]);
else {
this.highlyGeneric.complex.dict.add(args[3]);
}
break;
}
this.specificFilters.store(args[1], args[2] & 0b011, args[3]);
break;
default:
this.discardedCount += 1;
break;
}
}
if ( options.skipGenericCosmetic ) {
this.skipCompiledContent(reader, 'GENERIC');
return;
}
// Generic cosmetic filter section
reader.select('COSMETIC_FILTERS:GENERIC');
while ( reader.next() ) {
this.acceptedCount += 1;
const fingerprint = reader.fingerprint();
if ( this.duplicateBuster.has(fingerprint) ) {
this.discardedCount += 1;
continue;
}
this.duplicateBuster.add(fingerprint);
const args = reader.args();
switch ( args[0] ) {
// low generic
case 0: {
if ( this.lowlyGeneric.has(args[1]) ) {
const selector = this.lowlyGeneric.get(args[1]);
this.lowlyGeneric.set(args[1], `${selector},\n${args[2]}`);
} else {
this.lowlyGeneric.set(args[1], args[2]);
}
break;
}
// High-high generic hide/simple selectors
// div[id^="allo"]
case 4:
this.highlyGeneric.simple.dict.add(args[1]);
break;
// High-high generic hide/complex selectors
// div[id^="allo"] > span
case 5:
this.highlyGeneric.complex.dict.add(args[1]);
break;
default:
this.discardedCount += 1;
break;
}
}
};
/******************************************************************************/
FilterContainer.prototype.skipCompiledContent = function(reader, sectionId) {
reader.select(`COSMETIC_FILTERS:${sectionId}`);
while ( reader.next() ) {
this.acceptedCount += 1;
this.discardedCount += 1;
}
};
/******************************************************************************/
FilterContainer.prototype.toSelfie = function() {
return {
version: this.selfieVersion,
acceptedCount: this.acceptedCount,
discardedCount: this.discardedCount,
specificFilters: this.specificFilters.toSelfie(),
lowlyGeneric: Array.from(this.lowlyGeneric),
highSimpleGenericHideArray: Array.from(this.highlyGeneric.simple.dict),
highComplexGenericHideArray: Array.from(this.highlyGeneric.complex.dict),
};
};
/******************************************************************************/
FilterContainer.prototype.fromSelfie = function(selfie) {
if ( selfie.version !== this.selfieVersion ) {
throw new Error(
`cosmeticFilteringEngine: mismatched selfie version, ${selfie.version}, expected ${this.selfieVersion}`
);
}
this.acceptedCount = selfie.acceptedCount;
this.discardedCount = selfie.discardedCount;
this.specificFilters.fromSelfie(selfie.specificFilters);
this.lowlyGeneric = new Map(selfie.lowlyGeneric);
this.highlyGeneric.simple.dict = new Set(selfie.highSimpleGenericHideArray);
this.highlyGeneric.simple.str = selfie.highSimpleGenericHideArray.join(',\n');
this.highlyGeneric.complex.dict = new Set(selfie.highComplexGenericHideArray);
this.highlyGeneric.complex.str = selfie.highComplexGenericHideArray.join(',\n');
this.frozen = true;
};
/******************************************************************************/
FilterContainer.prototype.triggerSelectorCachePruner = function() {
// Of interest: http://fitzgeraldnick.com/weblog/40/
// http://googlecode.blogspot.ca/2009/07/gmail-for-mobile-html5-series-using.html
if ( this.selectorCacheTimer !== null ) { return; }
this.selectorCacheTimer = vAPI.setTimeout(
( ) => { this.pruneSelectorCacheAsync(); },
this.selectorCachePruneDelay
);
};
/******************************************************************************/
FilterContainer.prototype.addToSelectorCache = function(details) {
const hostname = details.hostname;
if ( typeof hostname !== 'string' || hostname === '' ) { return; }
const selectors = details.selectors;
if ( Array.isArray(selectors) === false ) { return; }
let entry = this.selectorCache.get(hostname);
if ( entry === undefined ) {
entry = SelectorCacheEntry.factory();
this.selectorCache.set(hostname, entry);
if ( this.selectorCache.size > this.selectorCacheCountMax ) {
this.triggerSelectorCachePruner();
}
}
entry.add(details);
};
/******************************************************************************/
FilterContainer.prototype.removeFromSelectorCache = function(
targetHostname = '*',
type = undefined
) {
const targetHostnameLength = targetHostname.length;
for ( let entry of this.selectorCache ) {
let hostname = entry[0];
let item = entry[1];
if ( targetHostname !== '*' ) {
if ( hostname.endsWith(targetHostname) === false ) { continue; }
if (
hostname.length !== targetHostnameLength &&
hostname.charAt(hostname.length - targetHostnameLength - 1) !== '.'
) {
continue;
}
}
item.remove(type);
}
};
/******************************************************************************/
FilterContainer.prototype.pruneSelectorCacheAsync = function() {
this.selectorCacheTimer = null;
if ( this.selectorCache.size <= this.selectorCacheCountMax ) { return; }
const cache = this.selectorCache;
const hostnames = Array.from(cache.keys())
.sort((a, b) => cache.get(b).accessId - cache.get(a).accessId)
.slice(this.selectorCacheCountMin);
for ( const hn of hostnames ) {
cache.get(hn).dispose();
cache.delete(hn);
}
};
/******************************************************************************/
FilterContainer.prototype.disableSurveyor = function(details) {
const hostname = details.hostname;
if ( typeof hostname !== 'string' || hostname === '' ) { return; }
const cacheEntry = this.selectorCache.get(hostname);
if ( cacheEntry === undefined ) { return; }
cacheEntry.disableSurveyor = true;
};
/******************************************************************************/
FilterContainer.prototype.cssRuleFromProcedural = function(pfilter) {
if ( pfilter.cssable !== true ) { return; }
const { tasks, action } = pfilter;
let mq;
if ( tasks !== undefined ) {
if ( tasks.length > 1 ) { return; }
if ( tasks[0][0] !== 'matches-media' ) { return; }
mq = tasks[0][1];
}
let style;
if ( Array.isArray(action) ) {
if ( action[0] !== 'style' ) { return; }
style = action[1];
}
if ( mq === undefined && style === undefined ) { return; }
if ( mq === undefined ) {
return `${pfilter.selector}\n{${style}}`;
}
if ( style === undefined ) {
return `@media ${mq} {\n${pfilter.selector}\n{display:none!important;}\n}`;
}
return `@media ${mq} {\n${pfilter.selector}\n{${style}}\n}`;
};
/******************************************************************************/
FilterContainer.prototype.retrieveGenericSelectors = function(request) {
if ( this.lowlyGeneric.size === 0 ) { return; }
if ( Array.isArray(request.hashes) === false ) { return; }
if ( request.hashes.length === 0 ) { return; }
const selectorsSet = new Set();
const hashes = [];
const safeOnly = request.safeOnly === true;
for ( const hash of request.hashes ) {
const bucket = this.lowlyGeneric.get(hash);
if ( bucket === undefined ) { continue; }
for ( const selector of bucket.split(',\n') ) {
if ( safeOnly && selector === keyFromSelector(selector) ) { continue; }
selectorsSet.add(selector);
}
hashes.push(hash);
}
// Apply exceptions: it is the responsibility of the caller to provide
// the exceptions to be applied.
const excepted = [];
if ( selectorsSet.size !== 0 && Array.isArray(request.exceptions) ) {
for ( const exception of request.exceptions ) {
if ( selectorsSet.delete(exception) ) {
excepted.push(exception);
}
}
}
if ( selectorsSet.size === 0 && excepted.length === 0 ) { return; }
const out = { injectedCSS: '', excepted, };
const selectors = Array.from(selectorsSet);
if ( typeof request.hostname === 'string' && request.hostname !== '' ) {
this.addToSelectorCache({
hostname: request.hostname,
selectors,
hashes,
type: 'cosmetic',
});
}
if ( selectors.length === 0 ) { return out; }
out.injectedCSS = `${selectors.join(',\n')}\n{display:none!important;}`;
vAPI.tabs.insertCSS(request.tabId, {
code: out.injectedCSS,
frameId: request.frameId,
matchAboutBlank: true,
runAt: 'document_start',
});
return out;
};
/******************************************************************************/
FilterContainer.prototype.retrieveSpecificSelectors = function(
request,
options
) {
const hostname = request.hostname;
const cacheEntry = this.selectorCache.get(hostname);
// https://github.com/chrisaljoudi/uBlock/issues/587
// out.ready will tell the content script the cosmetic filtering engine is
// up and ready.
// https://github.com/chrisaljoudi/uBlock/issues/497
// Generic exception filters are to be applied on all pages.
const out = {
ready: this.frozen,
hostname: hostname,
domain: request.domain,
exceptionFilters: [],
exceptedFilters: [],
proceduralFilters: [],
convertedProceduralFilters: [],
disableSurveyor: this.lowlyGeneric.size === 0,
};
const injectedCSS = [];
if (
options.noSpecificCosmeticFiltering !== true ||
options.noGenericCosmeticFiltering !== true
) {
const specificSet = this.$specificSet;
const proceduralSet = this.$proceduralSet;
const exceptionSet = this.$exceptionSet;
const dummySet = this.$dummySet;
// Cached cosmetic filters: these are always declarative.
if ( cacheEntry !== undefined ) {
cacheEntry.retrieveCosmetic(specificSet, out.genericCosmeticHashes = []);
if ( cacheEntry.disableSurveyor ) {
out.disableSurveyor = true;
}
}
// Retrieve filters with a non-empty hostname
const retrieveSets = [ specificSet, exceptionSet, proceduralSet, exceptionSet ];
const discardSets = [ dummySet, exceptionSet ];
this.specificFilters.retrieve(
hostname,
options.noSpecificCosmeticFiltering ? discardSets : retrieveSets,
1
);
// Retrieve filters with a regex-based hostname value
this.specificFilters.retrieve(
hostname,
options.noSpecificCosmeticFiltering ? discardSets : retrieveSets,
3
);
// Retrieve filters with a entity-based hostname value
if ( request.entity !== '' ) {
this.specificFilters.retrieve(
`${hostname.slice(0, -request.domain.length)}${request.entity}`,
options.noSpecificCosmeticFiltering ? discardSets : retrieveSets,
1
);
}
// Retrieve filters with an empty hostname
this.specificFilters.retrieve(
hostname,
options.noGenericCosmeticFiltering ? discardSets : retrieveSets,
2
);
// Apply exceptions to specific filterset
if ( exceptionSet.size !== 0 ) {
out.exceptionFilters = Array.from(exceptionSet);
for ( const selector of specificSet ) {
if ( exceptionSet.has(selector) === false ) { continue; }
specificSet.delete(selector);
out.exceptedFilters.push(selector);
}
}
if ( specificSet.size !== 0 ) {
injectedCSS.push(
`${Array.from(specificSet).join(',\n')}\n{display:none!important;}`
);
}
// Apply exceptions to procedural filterset.
// Also, some procedural filters are really declarative cosmetic
// filters, so we extract and inject them immediately.
if ( proceduralSet.size !== 0 ) {
for ( const json of proceduralSet ) {
const pfilter = JSON.parse(json);
if ( exceptionSet.has(json) ) {
proceduralSet.delete(json);
out.exceptedFilters.push(json);
continue;
}
if ( exceptionSet.has(pfilter.raw) ) {
proceduralSet.delete(json);
out.exceptedFilters.push(pfilter.raw);
continue;
}
const cssRule = this.cssRuleFromProcedural(pfilter);
if ( cssRule === undefined ) { continue; }
injectedCSS.push(cssRule);
proceduralSet.delete(json);
out.convertedProceduralFilters.push(json);
}
out.proceduralFilters.push(...proceduralSet);
}
// Highly generic cosmetic filters: sent once along with specific ones.
// A most-recent-used cache is used to skip computing the resulting set
// of high generics for a given set of exceptions.
// The resulting set of high generics is stored as a string, ready to
// be used as-is by the content script. The string is stored
// indirectly in the mru cache: this is to prevent duplication of the
// string in memory, which I have observed occurs when the string is
// stored directly as a value in a Map.
if ( options.noGenericCosmeticFiltering !== true ) {
const exceptionSetHash = out.exceptionFilters.join();
for ( const key in this.highlyGeneric ) {
const entry = this.highlyGeneric[key];
let str = entry.mru.lookup(exceptionSetHash);
if ( str === undefined ) {
str = { s: entry.str, excepted: [] };
let genericSet = entry.dict;
let hit = false;
for ( const exception of exceptionSet ) {
if ( (hit = genericSet.has(exception)) ) { break; }
}
if ( hit ) {
genericSet = new Set(entry.dict);
for ( const exception of exceptionSet ) {
if ( genericSet.delete(exception) ) {
str.excepted.push(exception);
}
}
str.s = Array.from(genericSet).join(',\n');
}
entry.mru.add(exceptionSetHash, str);
}
if ( str.excepted.length !== 0 ) {
out.exceptedFilters.push(...str.excepted);
}
if ( str.s.length !== 0 ) {
injectedCSS.push(`${str.s}\n{display:none!important;}`);
}
}
}
// Important: always clear used registers before leaving.
specificSet.clear();
proceduralSet.clear();
exceptionSet.clear();
dummySet.clear();
}
const details = {
code: '',
frameId: request.frameId,
matchAboutBlank: true,
runAt: 'document_start',
};
// Inject all declarative-based filters as a single stylesheet.
if ( injectedCSS.length !== 0 ) {
out.injectedCSS = injectedCSS.join('\n\n');
details.code = out.injectedCSS;
if ( request.tabId !== undefined ) {
vAPI.tabs.insertCSS(request.tabId, details);
}
}
// CSS selectors for collapsible blocked elements
if ( cacheEntry ) {
const networkFilters = [];
if ( cacheEntry.retrieveNet(networkFilters) ) {
details.code = `${networkFilters.join('\n')}\n{display:none!important;}`;
if ( request.tabId !== undefined ) {
vAPI.tabs.insertCSS(request.tabId, details);
}
}
}
return out;
};
/******************************************************************************/
FilterContainer.prototype.getFilterCount = function() {
return this.acceptedCount - this.discardedCount;
};
/******************************************************************************/
FilterContainer.prototype.dump = function() {
const generics = [];
for ( const selectors of this.lowlyGeneric.values() ) {
generics.push(...selectors.split(',\n'));
}
return [
'Cosmetic Filtering Engine internals:',
`specific: ${this.specificFilters.size}`,
`generic: ${generics.length}`,
`+ selectors: ${this.lowlyGeneric.size}`,
...generics.map(a => ` ${a}`),
].join('\n');
};
/******************************************************************************/
const cosmeticFilteringEngine = new FilterContainer();
export default cosmeticFilteringEngine;
/******************************************************************************/