58 lines
1.7 KiB
TypeScript
58 lines
1.7 KiB
TypeScript
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/* eslint-disable header/header */
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/*!
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* crxToZip
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* Copyright (c) 2013 Rob Wu <rob@robwu.nl>
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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export function crxToZip(buf: Buffer) {
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function calcLength(a: number, b: number, c: number, d: number) {
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let length = 0;
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length += a << 0;
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length += b << 8;
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length += c << 16;
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length += d << 24 >>> 0;
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return length;
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}
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// 50 4b 03 04
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// This is actually a zip file
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if (buf[0] === 80 && buf[1] === 75 && buf[2] === 3 && buf[3] === 4) {
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return buf;
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}
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// 43 72 32 34 (Cr24)
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if (buf[0] !== 67 || buf[1] !== 114 || buf[2] !== 50 || buf[3] !== 52) {
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throw new Error("Invalid header: Does not start with Cr24");
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}
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// 02 00 00 00
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// or
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// 03 00 00 00
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const isV3 = buf[4] === 3;
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const isV2 = buf[4] === 2;
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if ((!isV2 && !isV3) || buf[5] || buf[6] || buf[7]) {
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throw new Error("Unexpected crx format version number.");
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}
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if (isV2) {
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const publicKeyLength = calcLength(buf[8], buf[9], buf[10], buf[11]);
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const signatureLength = calcLength(buf[12], buf[13], buf[14], buf[15]);
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// 16 = Magic number (4), CRX format version (4), lengths (2x4)
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const zipStartOffset = 16 + publicKeyLength + signatureLength;
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return buf.subarray(zipStartOffset, buf.length);
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}
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// v3 format has header size and then header
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const headerSize = calcLength(buf[8], buf[9], buf[10], buf[11]);
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const zipStartOffset = 12 + headerSize;
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return buf.subarray(zipStartOffset, buf.length);
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}
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