chrome-adblock/background.js

const LISTS = [
  "https://raw.githubusercontent.com/easylist/easylist/gh-pages/easylist.txt",
  "https://raw.githubusercontent.com/easylist/easylist/gh-pages/easyprivacy.txt",
  "https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/filters.txt",
  "https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/quick-fixes.txt",
  "https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/privacy.txt",
  "https://raw.githubusercontent.com/uBlockOrigin/uAssets/master/filters/unbreak.txt",
  "https://raw.githubusercontent.com/brave/adblock-lists/master/brave-lists/brave-specific.txt"
];

const ENV = new Set(["env_chromium", "ext_ublock", "env_mv3"]);

const TYPE_MAP = {
  script: "script", image: "image", img: "image", stylesheet: "stylesheet", css: "stylesheet",
  object: "object", "object-subrequest": "object", xmlhttprequest: "xmlhttprequest", xhr: "xmlhttprequest",
  subdocument: "sub_frame", frame: "sub_frame", ping: "ping", beacon: "ping", media: "media",
  font: "font", websocket: "websocket", other: "other", document: "main_frame", doc: "main_frame"
};

const ALL_TYPES = ["main_frame", "sub_frame", "stylesheet", "script", "image", "font", "object", "xmlhttprequest", "ping", "csp_report", "media", "websocket", "webtransport", "webbundle", "other"];

const METHODS = new Set(["connect", "delete", "get", "head", "options", "patch", "post", "put", "other"]);

const ALIAS = {
  "abort-on-property-read": "aopr", aopr: "aopr",
  "abort-on-property-write": "aopw", aopw: "aopw",
  "abort-current-script": "acs", acs: "acs", "abort-current-inline-script": "acs", acis: "acs",
  "set-constant": "set", set: "set",
  "trusted-set-constant": "trusted-set", "trusted-set": "trusted-set",
  "no-setTimeout-if": "nostif", nostif: "nostif", "prevent-setTimeout": "nostif", "setTimeout-defuser": "nostif",
  "no-setInterval-if": "nosiif", nosiif: "nosiif", "prevent-setInterval": "nosiif", "setInterval-defuser": "nosiif",
  "nano-setTimeout-booster": "nano-stb", "nano-stb": "nano-stb", "adjust-setTimeout": "nano-stb",
  "nano-setInterval-booster": "nano-sib", "nano-sib": "nano-sib", "adjust-setInterval": "nano-sib",
  "addEventListener-defuser": "aeld", aeld: "aeld", "prevent-addEventListener": "aeld",
  "no-window-open-if": "nowoif", nowoif: "nowoif", "window.open-defuser": "nowoif", "prevent-window-open": "nowoif",
  "no-fetch-if": "no-fetch-if", "prevent-fetch": "no-fetch-if",
  "no-xhr-if": "no-xhr-if", "prevent-xhr": "no-xhr-if",
  noeval: "noeval", "silent-noeval": "noeval",
  "noeval-if": "noeval-if", "prevent-eval-if": "noeval-if",
  "remove-attr": "ra", ra: "ra",
  "remove-class": "rc", rc: "rc",
  "set-local-storage-item": "set-local-storage-item",
  "remove-cookie": "remove-cookie", "cookie-remover": "remove-cookie",
  "json-prune": "json-prune",
  "json-prune-fetch-response": "json-prune-fetch-response",
  "json-prune-xhr-response": "json-prune-xhr-response",
  "trusted-replace-fetch-response": "trusted-replace-fetch-response",
  "trusted-replace-xhr-response": "trusted-replace-xhr-response"
};

const YT_CORE = "playerResponse.adPlacements playerResponse.playerAds playerResponse.adSlots adPlacements playerAds adSlots";
const YT_DEFAULTS = [
  { t: "json-prune", a: [YT_CORE] },
  { t: "json-prune", a: ["entries.[-].command.reelWatchEndpoint.adClientParams.isAd"] },
  { t: "json-prune-fetch-response", a: [YT_CORE + " [].playerResponse.adPlacements [].playerResponse.adSlots", "", "propsToMatch", "/player?"] },
  { t: "json-prune-xhr-response", a: [YT_CORE, "", "propsToMatch", "/\\/player(?:\\?.+)?$/"] }
];

const PROCEDURAL = /:(has-text|-abp-[\w-]+|upward|xpath|matches-[\w-]+|style|remove|remove-attr|remove-class|min-text-length|watch-attr|others|if|if-not|nth-ancestor|contains|properties|spath|shadow)\(/;

const ASCII = /^[\x21-\x7e]*$/;
const DOMAIN = /^[a-z0-9-]+(\.[a-z0-9-]+)+$/;

function evalExpr(expr) {
  const t = expr.match(/!|&&|\|\||\(|\)|[\w-]+/g) || [];
  let i = 0;
  const unary = () => {
    if (t[i] === "!") { i++; return !unary(); }
    if (t[i] === "(") { i++; const v = or(); i++; return v; }
    return ENV.has(t[i++]);
  };
  const and = () => { let v = unary(); while (t[i] === "&&") { i++; const r = unary(); v = v && r; } return v; };
  const or = () => { let v = and(); while (t[i] === "||") { i++; const r = and(); v = v || r; } return v; };
  return or();
}

function splitArgs(s) {
  const out = [];
  let cur = "";
  let q = null;
  for (let i = 0; i < s.length; i++) {
    const c = s[i];
    if (c === "\\" && s[i + 1] === ",") { cur += ","; i++; continue; }
    if (q) { if (c === q) q = null; cur += c; continue; }
    if ((c === "'" || c === '"' || c === "`") && cur.trim() === "") { q = c; cur += c; continue; }
    if (c === ",") { out.push(cur); cur = ""; continue; }
    cur += c;
  }
  out.push(cur);
  return out.map(a => {
    a = a.trim();
    if (a.length >= 2 && "'\"`".includes(a[0]) && a[a.length - 1] === a[0]) a = a.slice(1, -1);
    return a;
  });
}

function parseDomains(s) {
  const inc = [];
  const exc = [];
  for (let d of s.split(",")) {
    d = d.trim().toLowerCase();
    if (!d || d.startsWith("/")) continue;
    const neg = d.startsWith("~");
    if (neg) d = d.slice(1);
    if (!/^[a-z0-9.*-]+$/.test(d)) continue;
    (neg ? exc : inc).push(d);
  }
  return { inc, exc };
}

function netRule(line) {
  let allow = false;
  if (line.startsWith("@@")) { allow = true; line = line.slice(2); }
  let pattern = line;
  let opts = [];
  const di = line.lastIndexOf("$");
  if (di >= 0 && !(line.startsWith("/") && line.endsWith("/"))) {
    pattern = line.slice(0, di);
    opts = line.slice(di + 1).split(",").map(o => o.trim()).filter(Boolean);
  }
  if (pattern.length > 2 && pattern.startsWith("/") && pattern.endsWith("/")) return null;
  const canon = (allow ? "@@" : "") + pattern + "$" + opts.filter(o => o !== "badfilter").sort().join(",");
  const types = [];
  const exTypes = [];
  const init = [];
  const exInit = [];
  const req = [];
  const exReq = [];
  const methods = [];
  const exMethods = [];
  let domainType = null;
  let important = false;
  let caseSensitive = false;
  let badfilter = false;
  let ghide = false;
  for (const o of opts) {
    const eq = o.indexOf("=");
    let name = eq >= 0 ? o.slice(0, eq) : o;
    const value = eq >= 0 ? o.slice(eq + 1) : "";
    const neg = name.startsWith("~");
    if (neg) name = name.slice(1);
    if (TYPE_MAP[name]) { (neg ? exTypes : types).push(TYPE_MAP[name]); continue; }
    switch (name) {
      case "all": types.push(...ALL_TYPES); break;
      case "third-party": case "3p": case "strict3p": domainType = neg ? "firstParty" : "thirdParty"; break;
      case "first-party": case "1p": case "strict1p": domainType = neg ? "thirdParty" : "firstParty"; break;
      case "important": important = true; break;
      case "match-case": caseSensitive = !neg; break;
      case "badfilter": badfilter = true; break;
      case "generichide": case "ghide": case "elemhide": case "ehide":
        if (!allow) return null;
        ghide = true;
        break;
      case "domain": case "from": case "to": {
        const tInc = name === "to" ? req : init;
        const tExc = name === "to" ? exReq : exInit;
        for (let v of value.split("|")) {
          v = v.trim().toLowerCase();
          const vneg = v.startsWith("~");
          if (vneg) v = v.slice(1);
          if (!v || !DOMAIN.test(v)) { if (!vneg) return null; continue; }
          (vneg ? tExc : tInc).push(v);
        }
        break;
      }
      case "method":
        for (let v of value.split("|")) {
          v = v.trim().toLowerCase();
          const vneg = v.startsWith("~");
          if (vneg) v = v.slice(1);
          if (!METHODS.has(v)) return null;
          (vneg ? exMethods : methods).push(v);
        }
        break;
      default:
        return null;
    }
  }
  if (badfilter) return { kind: "badfilter", canon };
  if (ghide) {
    const m = /^\|\|([a-z0-9.-]+)\^?\|?$/.exec(pattern);
    return m ? { kind: "ghide", host: m[1] } : null;
  }
  if (pattern === "*" || pattern === "|" || pattern === "||") pattern = "";
  if (pattern.startsWith("||*")) pattern = pattern.slice(2);
  while (pattern.startsWith("*")) pattern = pattern.slice(1);
  while (pattern.endsWith("*")) pattern = pattern.slice(0, -1);
  if (!ASCII.test(pattern)) return null;
  if (/.\|./.test(pattern.replace(/^\|\|?/, "").replace(/\|$/, ""))) return null;
  if (!pattern && !init.length && !req.length) return null;
  if (pattern && pattern.replace(/[|^*]/g, "").length < 3 && !init.length && !req.length) return null;
  let tlist = [...new Set(types)];
  const xlist = [...new Set(exTypes)];
  if (tlist.length && xlist.length) tlist = tlist.filter(t => !xlist.includes(t));
  if (types.length && !tlist.length) return null;
  let action = allow ? "allow" : "block";
  if (allow && tlist.includes("main_frame")) {
    action = "allowAllRequests";
    tlist = ["main_frame", "sub_frame"];
  }
  const condition = {};
  if (pattern) condition.urlFilter = pattern;
  if (caseSensitive && pattern) condition.isUrlFilterCaseSensitive = true;
  if (tlist.length) condition.resourceTypes = tlist;
  else if (xlist.length) condition.excludedResourceTypes = xlist;
  if (domainType) condition.domainType = domainType;
  if (init.length) condition.initiatorDomains = [...new Set(init)];
  if (exInit.length) condition.excludedInitiatorDomains = [...new Set(exInit)];
  if (req.length) condition.requestDomains = [...new Set(req)];
  if (exReq.length) condition.excludedRequestDomains = [...new Set(exReq)];
  if (methods.length) condition.requestMethods = [...new Set(methods)];
  if (exMethods.length) condition.excludedRequestMethods = [...new Set(exMethods)];
  const priority = action === "block" ? (important ? 3 : 1) : 2;
  const keys = Object.keys(condition);
  const dm = /^\|\|([a-z0-9-]+(?:\.[a-z0-9-]+)+)\^?$/.exec(pattern);
  const mergeable = dm && action !== "allowAllRequests" && keys.every(k => k === "urlFilter" || k === "domainType");
  if (action === "allowAllRequests") {
    const hm = /^\|\|([a-z0-9.-]+)\^?\|?$/.exec(pattern);
    if (hm && !init.length) return { kind: "dnr", canon, action, priority, condition, docHost: hm[1] };
  }
  return { kind: "dnr", canon, action, priority, condition, merge: mergeable ? dm[1] : null };
}

function compile(texts) {
  const bad = new Set();
  const net = [];
  const generic = new Set();
  const genericExcAll = new Set();
  const hosts = new Map();
  const rec = h => {
    let r = hosts.get(h);
    if (!r) { r = { s: new Set(), x: new Set(), j: new Map(), jx: new Set(), g: false, d: false }; hosts.set(h, r); }
    return r;
  };
  for (const text of texts) {
    const stack = [];
    for (const raw of text.split(/\r?\n/)) {
      const line = raw.trim();
      if (line.startsWith("!#if ")) { stack.push(evalExpr(line.slice(5))); continue; }
      if (line.startsWith("!#else")) { if (stack.length) stack[stack.length - 1] = !stack[stack.length - 1]; continue; }
      if (line.startsWith("!#endif")) { stack.pop(); continue; }
      if (stack.some(v => !v)) continue;
      if (!line || line.startsWith("!") || line.startsWith("[")) continue;
      const cm = /^([^#]*)(#@?#)(.+)$/.exec(line);
      if (cm) {
        const { inc, exc } = parseDomains(cm[1]);
        const isExc = cm[2] === "#@#";
        const body = cm[3];
        if (body.startsWith("+js(") && body.endsWith(")")) {
          const inner = body.slice(4, -1);
          if (isExc) {
            if (!inc.length) continue;
            let key = "";
            if (inner.trim()) {
              const a = splitArgs(inner);
              const t = ALIAS[a.shift().replace(/\.js$/, "")];
              if (!t) continue;
              key = t + "|" + a.join("|");
            }
            for (const d of inc) rec(d).jx.add(key);
            continue;
          }
          if (!inc.length) continue;
          const a = splitArgs(inner);
          const t = ALIAS[a.shift().replace(/\.js$/, "")];
          if (!t) continue;
          const key = t + "|" + a.join("|");
          for (const d of inc) rec(d).j.set(key, { t, a });
          for (const d of exc) rec(d).jx.add(key);
          continue;
        }
        if (/^[#@$%?^]/.test(body) || body.startsWith("^")) continue;
        const sel = body.trim();
        if (!sel || PROCEDURAL.test(sel) || sel.includes("{") || sel.includes("}")) continue;
        if (isExc) {
          if (!inc.length) genericExcAll.add(sel);
          else for (const d of inc) rec(d).x.add(sel);
          continue;
        }
        if (!inc.length) generic.add(sel);
        else for (const d of inc) rec(d).s.add(sel);
        for (const d of exc) rec(d).x.add(sel);
        continue;
      }
      if (/#[@?$%]{1,2}#/.test(line)) continue;
      const r = netRule(line);
      if (!r) continue;
      if (r.kind === "badfilter") { bad.add(r.canon); continue; }
      if (r.kind === "ghide") { rec(r.host).g = true; continue; }
      net.push(r);
    }
  }
  for (const s of genericExcAll) generic.delete(s);
  for (const r of hosts.values()) for (const s of genericExcAll) r.s.delete(s);
  const groups = new Map();
  const rest = [];
  const seen = new Set();
  for (const r of net) {
    if (bad.has(r.canon)) continue;
    if (r.docHost) rec(r.docHost).d = true;
    if (r.merge) {
      const gk = r.action + "|" + r.priority + "|" + (r.condition.domainType || "");
      if (!groups.has(gk)) groups.set(gk, { action: r.action, priority: r.priority, domainType: r.condition.domainType, set: new Set() });
      groups.get(gk).set.add(r.merge);
      continue;
    }
    const sig = r.action + "|" + r.priority + "|" + JSON.stringify(r.condition);
    if (seen.has(sig)) continue;
    seen.add(sig);
    rest.push({ action: { type: r.action }, priority: r.priority, condition: r.condition });
  }
  const merged = [];
  for (const g of groups.values()) {
    const list = [...g.set];
    for (let i = 0; i < list.length; i += 1000) {
      const condition = { requestDomains: list.slice(i, i + 1000) };
      if (g.domainType) condition.domainType = g.domainType;
      merged.push({ action: { type: g.action }, priority: g.priority, condition });
    }
  }
  const allowFirst = [...merged, ...rest].sort((a, b) => (a.action.type === "block") - (b.action.type === "block"));
  const allows = allowFirst.filter(r => r.action.type !== "block");
  const blocksMerged = merged.filter(r => r.action.type === "block");
  const blocksRest = rest.filter(r => r.action.type === "block");
  const dnr = [...allows, ...blocksMerged, ...blocksRest];
  for (const h of ["youtube.com", "m.youtube.com", "music.youtube.com", "youtube-nocookie.com"]) {
    const r = rec(h);
    for (const d of YT_DEFAULTS) r.j.set(d.t + "|" + d.a.join("|"), d);
  }
  const out = {};
  let scriptletCount = 0;
  let specificCount = 0;
  for (const [h, r] of hosts) {
    const o = {};
    if (r.s.size) { o.s = [...r.s]; specificCount += r.s.size; }
    if (r.x.size) o.x = [...r.x];
    if (r.j.size) { o.j = [...r.j.values()]; scriptletCount += r.j.size; }
    if (r.jx.size) o.jx = [...r.jx];
    if (r.g) o.g = 1;
    if (r.d) o.d = 1;
    out["c:" + h] = o;
  }
  return { dnr, generic: [...generic], hosts: out, stats: { generic: generic.size, specific: specificCount, scriptlets: scriptletCount } };
}

async function update() {
  try {
    const texts = await Promise.all(LISTS.map(async u => {
      const r = await fetch(u, { cache: "no-store" });
      if (!r.ok) throw new Error(u + " returned " + r.status);
      return r.text();
    }));
    const c = compile(texts);
    const applied = await applyDnr(c.dnr);
    const keep = await chrome.storage.local.get("allowlist");
    await chrome.storage.local.clear();
    const meta = {
      updated: Date.now(),
      error: null,
      network: applied,
      networkTotal: c.dnr.length,
      generic: c.stats.generic,
      specific: c.stats.specific,
      scriptlets: c.stats.scriptlets
    };
    await chrome.storage.local.set({ ...c.hosts, generic: c.generic, meta, allowlist: keep.allowlist || [] });
    genericCache = null;
  } catch (e) {
    const d = await chrome.storage.local.get("meta");
    await chrome.storage.local.set({ meta: { ...(d.meta || {}), error: String(e), lastAttempt: Date.now() } });
  }
}

async function addRules(rules) {
  if (!rules.length) return 0;
  try {
    await chrome.declarativeNetRequest.updateDynamicRules({ addRules: rules });
    return rules.length;
  } catch (e) {
    if (rules.length === 1) return 0;
    const m = rules.length >> 1;
    return (await addRules(rules.slice(0, m))) + (await addRules(rules.slice(m)));
  }
}

async function applyDnr(list) {
  const max = (chrome.declarativeNetRequest.MAX_NUMBER_OF_DYNAMIC_RULES || 30000) - 1;
  const existing = await chrome.declarativeNetRequest.getDynamicRules();
  const removeRuleIds = existing.map(r => r.id).filter(id => id !== 1);
  if (removeRuleIds.length) await chrome.declarativeNetRequest.updateDynamicRules({ removeRuleIds });
  const rules = list.slice(0, max).map((r, i) => ({ id: i + 2, ...r }));
  let added = 0;
  for (let i = 0; i < rules.length; i += 5000) added += await addRules(rules.slice(i, i + 5000));
  return added;
}

async function syncAllowlist(list) {
  const rule = {
    id: 1,
    priority: 100,
    action: { type: "allowAllRequests" },
    condition: { requestDomains: list, resourceTypes: ["main_frame", "sub_frame"] }
  };
  await chrome.declarativeNetRequest.updateDynamicRules({ removeRuleIds: [1], addRules: list.length ? [rule] : [] });
}

let genericCache = null;

async function genericList() {
  if (!genericCache) {
    const d = await chrome.storage.local.get("generic");
    const list = d.generic || [];
    genericCache = { list, css: list.map(s => s + "{display:none!important}").join("\n") };
  }
  return genericCache;
}

function candidates(host) {
  const labels = host.toLowerCase().split(".");
  const out = [];
  for (let i = 0; i < labels.length - 1; i++) {
    const c = labels.slice(i).join(".");
    out.push(c);
    const p = labels.slice(i);
    if (p.length >= 2) out.push(p.slice(0, -1).join(".") + ".*");
    if (p.length >= 3) out.push(p.slice(0, -2).join(".") + ".*");
  }
  return [...new Set(out)];
}

async function lookup(host, top) {
  const cands = candidates(host);
  const d = await chrome.storage.local.get([...cands.map(c => "c:" + c), "allowlist"]);
  const allow = d.allowlist || [];
  if (cands.some(c => allow.includes(c))) return { css: "", scriptlets: [] };
  const recs = cands.map(c => d["c:" + c]).filter(Boolean);
  if (recs.some(r => r.d)) return { css: "", scriptlets: [] };
  const exc = new Set();
  const jexc = new Set();
  const spec = new Set();
  const js = new Map();
  let ghide = false;
  for (const r of recs) {
    if (r.x) r.x.forEach(s => exc.add(s));
    if (r.jx) r.jx.forEach(k => jexc.add(k));
    if (r.s) r.s.forEach(s => spec.add(s));
    if (r.j) r.j.forEach(x => js.set(x.t + "|" + x.a.join("|"), x));
    if (r.g) ghide = true;
  }
  const parts = [];
  for (const s of spec) if (!exc.has(s)) parts.push(s + "{display:none!important}");
  if (top && !ghide) {
    const g = await genericList();
    if (exc.size) {
      for (const s of g.list) if (!exc.has(s)) parts.push(s + "{display:none!important}");
    } else if (g.css) parts.push(g.css);
  }
  const scriptlets = jexc.has("") ? [] : [...js].filter(([k]) => !jexc.has(k)).map(([, v]) => v);
  return { css: parts.join("\n"), scriptlets };
}

async function handlePage(msg, sender) {
  if (!msg.host || !sender.tab) return { scriptlets: [] };
  const res = await lookup(msg.host, msg.top);
  if (res.css) {
    const target = sender.documentId
      ? { tabId: sender.tab.id, documentIds: [sender.documentId] }
      : { tabId: sender.tab.id, frameIds: [sender.frameId] };
    chrome.scripting.insertCSS({ target, css: res.css, origin: "USER" }).catch(() => {});
  }
  return { scriptlets: res.scriptlets };
}

async function toggle(host) {
  const d = await chrome.storage.local.get("allowlist");
  const set = new Set(d.allowlist || []);
  if (set.has(host)) set.delete(host); else set.add(host);
  const list = [...set];
  await chrome.storage.local.set({ allowlist: list });
  await syncAllowlist(list);
  return set.has(host);
}

async function maybeUpdate() {
  const d = await chrome.storage.local.get("meta");
  if (!d.meta || !d.meta.updated || Date.now() - d.meta.updated > 6 * 3600 * 1000) await update();
}

chrome.runtime.onInstalled.addListener(() => {
  chrome.alarms.create("update", { periodInMinutes: 360 });
  update();
});
chrome.runtime.onStartup.addListener(() => {
  chrome.alarms.create("update", { periodInMinutes: 360 });
  maybeUpdate();
});
chrome.alarms.onAlarm.addListener(a => { if (a.name === "update") update(); });
chrome.runtime.onMessage.addListener((msg, sender, reply) => {
  if (!msg) return;
  if (msg.cmd === "page") { handlePage(msg, sender).then(reply, () => reply({ scriptlets: [] })); return true; }
  if (msg.cmd === "update") { update().then(() => reply(true)); return true; }
  if (msg.cmd === "toggle") { toggle(msg.host).then(reply); return true; }
});