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reverselookup-worker.js
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298 lines (263 loc) · 9.9 KB
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/*******************************************************************************
uBlock Origin - a browser extension to block requests.
Copyright (C) 2015-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
*/
/* global onmessage, postMessage */
'use strict';
/******************************************************************************/
var listEntries = Object.create(null),
reBlockStart = /^#block-start-(\d+)\n/gm;
/******************************************************************************/
var extractBlocks = function(content, begId, endId) {
reBlockStart.lastIndex = 0;
var out = [];
var match = reBlockStart.exec(content);
while ( match !== null ) {
var beg = match.index + match[0].length;
var blockId = parseInt(match[1], 10);
if ( blockId >= begId && blockId < endId ) {
var end = content.indexOf('#block-end-' + match[1], beg);
out.push(content.slice(beg, end));
reBlockStart.lastIndex = end;
}
match = reBlockStart.exec(content);
}
return out.join('\n');
};
/******************************************************************************/
var fromNetFilter = function(details) {
var lists = [],
compiledFilter = details.compiledFilter;
for ( let assetKey in listEntries ) {
let entry = listEntries[assetKey];
if ( entry === undefined ) { continue; }
let content = extractBlocks(entry.content, 0, 1000);
let pos = 0;
for (;;) {
pos = content.indexOf(compiledFilter, pos);
if ( pos === -1 ) { break; }
// We need an exact match.
// https://github.com/gorhill/uBlock/issues/1392
// https://github.com/gorhill/uBlock/issues/835
let notFound = pos !== 0 && content.charCodeAt(pos - 1) !== 0x0A;
pos += compiledFilter.length;
if (
notFound ||
pos !== content.length && content.charCodeAt(pos) !== 0x0A
) {
continue;
}
lists.push({
assetKey: assetKey,
title: entry.title,
supportURL: entry.supportURL
});
break;
}
}
let response = {};
response[details.rawFilter] = lists;
postMessage({
id: details.id,
response: response
});
};
/******************************************************************************/
// Looking up filter lists from a cosmetic filter is a bit more complicated
// than with network filters:
//
// The filter is its raw representation, not its compiled version. This is
// because the cosmetic filtering engine can't translate a live cosmetic
// filter into its compiled version. Reason is I do not want to burden
// cosmetic filtering with the resource overhead of being able to re-compile
// live cosmetic filters. I want the cosmetic filtering code to be left
// completely unaffected by reverse lookup requirements.
//
// Mainly, given a CSS selector and a hostname as context, we will derive
// various versions of compiled filters and see if there are matches. This way
// the whole CPU cost is incurred by the reverse lookup code -- in a worker
// thread, and the cosmetic filtering engine incurs no cost at all.
//
// For this though, the reverse lookup code here needs some knowledge of
// the inners of the cosmetic filtering engine.
// FilterContainer.fromCompiledContent() is our reference code to create
// the various compiled versions.
let fromCosmeticFilter = function(details) {
let match = /^#@?#\^?/.exec(details.rawFilter),
prefix = match[0],
exception = prefix.charAt(1) === '@',
selector = details.rawFilter.slice(prefix.length);
// The longer the needle, the lower the number of false positives.
let needle = selector.match(/\w+/g).reduce(function(a, b) {
return a.length > b.length ? a : b;
});
let reHostname = new RegExp(
'^' +
details.hostname.split('.').reduce(
function(acc, item) {
return acc === ''
? item
: '(' + acc + '\\.)?' + item;
},
''
) +
'$'
);
let reEntity,
domain = details.domain,
pos = domain.indexOf('.');
if ( pos !== -1 ) {
reEntity = new RegExp(
'^' +
domain.slice(0, pos).split('.').reduce(
function(acc, item) {
return acc === ''
? item
: '(' + acc + '\\.)?' + item;
},
''
) +
'\\.\\*$'
);
}
let hostnameMatches = hn => {
return hn === '' ||
reHostname.test(hn) ||
reEntity !== undefined && reEntity.test(hn);
};
let response = Object.create(null);
for ( let assetKey in listEntries ) {
let entry = listEntries[assetKey];
if ( entry === undefined ) { continue; }
let content = extractBlocks(entry.content, 1000, 2000),
isProcedural,
found;
let pos = 0;
while ( (pos = content.indexOf(needle, pos)) !== -1 ) {
let beg = content.lastIndexOf('\n', pos);
if ( beg === -1 ) { beg = 0; }
let end = content.indexOf('\n', pos);
if ( end === -1 ) { end = content.length; }
pos = end;
let fargs = JSON.parse(content.slice(beg, end));
// https://github.com/gorhill/uBlock/issues/2763
if ( fargs[0] >= 0 && fargs[0] <= 5 && details.ignoreGeneric ) {
continue;
}
switch ( fargs[0] ) {
// Lowly generic cosmetic filters
case 0: // simple id-based
if (
fargs[1] === selector.slice(1) &&
selector.charAt(0) === '#'
) {
found = prefix + selector;
}
break;
case 2: // simple class-based
if (
fargs[1] === selector.slice(1) &&
selector.charAt(0) === '.'
) {
found = prefix + selector;
}
break;
case 1: // complex id-based
case 3: // complex class-based
if ( fargs[2] === selector ) {
found = prefix + selector;
}
break;
// Highly generic cosmetic filters
case 4: // simple highly generic
case 5: // complex highly generic
case 7: // generic exception
if ( fargs[1] === selector ) {
found = prefix + selector;
}
break;
// Specific cosmetic filtering
case 8:
if ( exception !== ((fargs[1] & 0b0001) !== 0) ) { break; }
isProcedural = (fargs[1] & 0b0010) !== 0;
if (
isProcedural === false && fargs[3] !== selector ||
isProcedural && JSON.parse(fargs[3]).raw !== selector
) {
break;
}
if ( hostnameMatches(fargs[2]) ) {
found = fargs[2] + prefix + selector;
}
break;
// Scriptlet injection
case 32:
if ( exception !== ((fargs[1] & 0b0001) !== 0) ) { break; }
if ( fargs[3] !== selector ) { break; }
if ( hostnameMatches(fargs[2]) ) {
found = fargs[2] + prefix + selector;
}
break;
// HTML filtering
case 64: // CSS selector
case 65: // procedural
if ( exception !== ((fargs[1] & 0b0001) !== 0) ) { break; }
if (
fargs[0] === 64 && fargs[3] !== selector ||
fargs[0] === 65 && JSON.parse(fargs[3]).raw !== selector
) {
break;
}
if ( hostnameMatches(fargs[2]) ) {
found = fargs[2] + prefix + selector;
}
break;
}
if ( found !== undefined ) {
if ( response[found] === undefined ) {
response[found] = [];
}
response[found].push({
assetKey: assetKey,
title: entry.title,
supportURL: entry.supportURL
});
break;
}
}
}
postMessage({
id: details.id,
response: response
});
};
/******************************************************************************/
onmessage = function(e) { // jshint ignore:line
var msg = e.data;
switch ( msg.what ) {
case 'resetLists':
listEntries = Object.create(null);
break;
case 'setList':
listEntries[msg.details.assetKey] = msg.details;
break;
case 'fromNetFilter':
fromNetFilter(msg);
break;
case 'fromCosmeticFilter':
fromCosmeticFilter(msg);
break;
}
};
/******************************************************************************/