| |
| (() => { |
| 'use strict'; |
| const LABELS = ['content', 'ad', 'cookie', 'newsletter', 'notification', 'paywall']; |
| const DIMENSIONS = 4096; |
| const FEATURE_VERSION = 'dom-bow-2'; |
| const defaults = Object.freeze({ enabled: true, ads: true, network: true, annoyances: false, paywalls: false, disabledHosts: [] }); |
| const hash = (text) => { |
| let value = 2166136261; |
| for (let i = 0; i < text.length; i++) value = Math.imul(value ^ text.charCodeAt(i), 16777619); |
| return value >>> 0; |
| }; |
| function features(state) { |
| const result = new Map(); |
| const add = (name, value = 1) => { |
| const index = 32 + hash(name) % (DIMENSIONS - 32); |
| result.set(index, Math.min(3, (result.get(index) || 0) + value)); |
| }; |
| for (const field of ['text', 'attributes', 'resource']) { |
| const source = String(state[field] || '').slice(0, field === 'text' ? 512 : 256) |
| .replace(/([a-z])([A-Z])/g, '$1 $2').toLowerCase(); |
| const words = source.match(/[a-z][a-z0-9]{1,30}/g) || []; |
| for (let i = 0; i < words.length; i++) { |
| add(`${field}:${words[i]}`); |
| if (i) add(`${field}:${words[i - 1]} ${words[i]}`); |
| |
| if (field !== 'text') for (let j = 0; j < words[i].length - 2; j++) add(`${field}:~${words[i].slice(j, j + 3)}`, 0.25); |
| } |
| } |
| add(`tag:${state.tag || 'div'}`); |
| add(`role:${state.role || ''}`); |
| const numeric = [ |
| state.fixed ? 1 : 0, state.dialog ? 1 : 0, state.iframe ? 1 : 0, |
| state.image ? 1 : 0, state.thirdParty ? 1 : 0, |
| Math.min(1, (state.width || 0) / 1200), Math.min(1, (state.height || 0) / 900), |
| Math.min(1, (state.text || '').length / 512), Math.min(1, (state.links || 0) / 8), |
| state.hasForm ? 1 : 0, state.protected ? 1 : 0, |
| state.bannerShape ? 1 : 0, state.visible === false ? 0 : 1, |
| ]; |
| const norm = Math.sqrt([...result.values()].reduce((sum, x) => sum + x * x, 0)) || 1; |
| for (const [index, value] of result) result.set(index, value / norm); |
| |
| numeric.forEach((value, i) => { if (value) result.set(i, value * 0.2); }); |
| return [...result]; |
| } |
| function loadModel(artifact) { |
| if (artifact.featureVersion !== FEATURE_VERSION || artifact.dimensions !== DIMENSIONS || |
| JSON.stringify(artifact.labels) !== JSON.stringify(LABELS)) throw new Error('Incompatible model'); |
| const bytes = Uint8Array.from(atob(artifact.weights), c => c.charCodeAt(0)); |
| if (bytes.length !== DIMENSIONS * LABELS.length) throw new Error('Invalid model size'); |
| return { ...artifact, coefficients: new Int8Array(bytes.buffer) }; |
| } |
| function classify(state, model) { |
| const sparse = features(state); |
| const logits = LABELS.map((_, k) => { |
| let value = model.intercepts[k]; |
| for (const [index, x] of sparse) value += model.coefficients[k * DIMENSIONS + index] * model.scales[k] * x; |
| return value / model.temperature; |
| }); |
| const max = Math.max(...logits); |
| const exp = logits.map(x => Math.exp(x - max)); |
| const sum = exp.reduce((a, b) => a + b, 0); |
| const probabilities = Object.fromEntries(LABELS.map((label, i) => [label, exp[i] / sum])); |
| const choice = LABELS[logits.indexOf(max)]; |
| return { |
| category: { type: 'choice', choice, probabilities, confidence: probabilities[choice] }, |
| isAd: { type: 'binary', probability: probabilities.ad }, |
| isAnnoyance: { type: 'binary', probability: probabilities.cookie + probabilities.newsletter + probabilities.notification }, |
| isPaywall: { type: 'binary', probability: probabilities.paywall }, |
| }; |
| } |
| function decide(state, decision, settings, thresholds) { |
| if (!settings.enabled || state.visible === false || state.protected) return { action: 'keep', reason: 'protected-or-disabled' }; |
| const { choice, confidence } = decision.category; |
| if (choice === 'content') return { action: 'keep', reason: 'content' }; |
| if (confidence < (thresholds[choice] ?? 1)) return { action: 'keep', reason: 'uncertain' }; |
| if (choice === 'ad') return { action: settings.ads ? 'hide' : 'keep', reason: 'ad' }; |
| if ((state.text || '').trim().length < 20) return { action: 'keep', reason: 'insufficient-overlay-evidence' }; |
| |
| if (!(state.fixed || state.dialog)) return { action: 'keep', reason: 'not-an-overlay' }; |
| if (choice === 'paywall') return { action: settings.paywalls ? 'hide' : 'keep', reason: 'paywall-overlay' }; |
| return { action: settings.annoyances ? 'hide' : 'keep', reason: choice }; |
| } |
| function baseline(state) { |
| const attributes = `${state.attributes || ''} ${state.resource || ''}`.toLowerCase(); |
| const text = String(state.text || '').toLowerCase(); |
| return /(^|[\s_/-])(ad|ads|advert|advertisement|advertising|sponsored)([\s_/-]|$)/.test(attributes) || |
| /^(advertisement|sponsored|promoted)(\b|$)/.test(text.trim()); |
| } |
| globalThis.WebGuard = { LABELS, DIMENSIONS, FEATURE_VERSION, defaults, features, loadModel, classify, decide, baseline }; |
| })(); |
|
|
