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diff --git a/background/ResponseProcessor.mjs b/background/ResponseProcessor.mjs
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-/**
-* GNU LibreJS - A browser add-on to block nonfree nontrivial JavaScript.
-*
-* Copyright (C) 2018 Giorgio Maone <giorgio@maone.net>
-*
-* This file is part of GNU LibreJS.
-*
-* GNU LibreJS 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.
-*
-* GNU LibreJS 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 GNU LibreJS. If not, see <http://www.gnu.org/licenses/>.
-*/
-
-/**
- An abstraction layer over the StreamFilter API, allowing its clients to process
- only the "interesting" HTML and script requests and leaving the other alone
-*/
-
-import ResponseMetaData from './ResponseMetaData.mjs';
-import browser from '/common/browser.mjs';
-
-let listeners = new WeakMap();
-let webRequestEvent = browser.webRequest.onHeadersReceived;
-
-class ResponseProcessor {
-
- static install(handler, types = ["main_frame", "sub_frame"]) {
- if (listeners.has(handler)) return false;
- let listener =
- async request => await new ResponseTextFilter(request).process(handler);
- listeners.set(handler, listener);
- webRequestEvent.addListener(
- listener,
- {urls: ["<all_urls>"], types},
- ["blocking", "responseHeaders"]
- );
- return true;
- }
-
- static uninstall(handler) {
- let listener = listeners.get(handler);
- if (listener) {
- webRequestEvent.removeListener(listener);
- }
- }
-}
-
-Object.assign(ResponseProcessor, {
- // control flow values to be returned by handler.pre() callbacks
- ACCEPT: {},
- REJECT: {cancel: true},
- CONTINUE: null
-});
-
-class ResponseTextFilter {
- constructor(request) {
- this.request = request;
- let {type, statusCode} = request;
- let md = this.metaData = new ResponseMetaData(request);
- this.canProcess = // we want to process html documents and scripts only
- (statusCode < 300 || statusCode >= 400) && // skip redirections
- !md.disposition && // skip forced downloads
- (type === "script" || /\bhtml\b/i.test(md.contentType));
- }
-
- async process(handler) {
- if (!this.canProcess) return ResponseProcessor.ACCEPT;
- let {metaData, request} = this;
- let response = {request, metaData}; // we keep it around allowing callbacks to store state
- if (typeof handler.pre === "function") {
- let res = await handler.pre(response);
- if (res) return res;
- if (handler.post) handler = handler.post;
- if (typeof handler !== "function") return ResponseProcessor.ACCEPT;
- }
-
- return ResponseProcessor.ACCEPT;
-
- let {requestId, responseHeaders} = request;
- let filter = browser.webRequest.filterResponseData(requestId);
- let buffer = [];
-
- filter.ondata = event => {
- buffer.push(event.data);
- };
-
- filter.onstop = async event => {
- // concatenate chunks
- let size = buffer.reduce((sum, chunk, n) => sum + chunk.byteLength, 0)
- let allBytes = new Uint8Array(size);
- let pos = 0;
- for (let chunk of buffer) {
- allBytes.set(new Uint8Array(chunk), pos);
- pos += chunk.byteLength;
- }
- buffer = null; // allow garbage collection
- if (allBytes.indexOf(0) !== -1) {
- console.debug("Warning: zeroes in bytestream, probable cached encoding mismatch.", request);
- if (request.type === "script") {
- console.debug("It's a script, trying to refetch it.");
- response.text = await (await fetch(request.url, {cache: "reload", credentials: "include"})).text();
- } else {
- console.debug("It's a %s, trying to decode it as UTF-16.", request.type);
- response.text = new TextDecoder("utf-16be").decode(allBytes, {stream: true});
- }
- } else {
- response.text = metaData.decode(allBytes);
- }
- let editedText = null;
- try {
- editedText = await handler(response);
- } catch(e) {
- console.error(e);
- }
- if (editedText !== null) {
- // we changed the content, let's re-encode
- let encoded = new TextEncoder().encode(editedText);
- // pre-pending the UTF-8 BOM will force the charset per HTML 5 specs
- allBytes = new Uint8Array(encoded.byteLength + 3);
- allBytes.set(ResponseMetaData.UTF8BOM, 0); // UTF-8 BOM
- allBytes.set(encoded, 3);
- }
- filter.write(allBytes);
- filter.close();
- }
-
- return ResponseProcessor.ACCEPT;
- }
-}
-
-/* The following was originally in Storage.js */
-function url_item(url) {
- let queryPos = url.indexOf("?");
- return queryPos === -1 ? url : url.substring(0, queryPos);
-}
-
-export {ResponseProcessor, url_item};