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encoding.ts
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encoding.ts
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/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
'use strict';
import * as stream from 'vs/base/node/stream';
import * as iconv from 'iconv-lite';
import { TPromise } from 'vs/base/common/winjs.base';
import { isLinux, isMacintosh } from 'vs/base/common/platform';
import { exec } from 'child_process';
import { Readable, Writable, WritableOptions } from 'stream';
import { asWinJSImport } from 'vs/base/common/async';
export const UTF8 = 'utf8';
export const UTF8_with_bom = 'utf8bom';
export const UTF16be = 'utf16be';
export const UTF16le = 'utf16le';
export interface IDecodeStreamOptions {
guessEncoding?: boolean;
minBytesRequiredForDetection?: number;
overwriteEncoding?(detectedEncoding: string): string;
}
export function toDecodeStream(readable: Readable, options: IDecodeStreamOptions): TPromise<{ detected: IDetectedEncodingResult, stream: NodeJS.ReadableStream }> {
if (!options.minBytesRequiredForDetection) {
options.minBytesRequiredForDetection = options.guessEncoding ? AUTO_GUESS_BUFFER_MAX_LEN : NO_GUESS_BUFFER_MAX_LEN;
}
if (!options.overwriteEncoding) {
options.overwriteEncoding = detected => detected || UTF8;
}
return new TPromise<{ detected: IDetectedEncodingResult, stream: NodeJS.ReadableStream }>((resolve, reject) => {
readable.pipe(new class extends Writable {
private _decodeStream: NodeJS.ReadWriteStream;
private _decodeStreamConstruction: Thenable<any>;
private _buffer: Buffer[] = [];
private _bytesBuffered = 0;
constructor(opts?: WritableOptions) {
super(opts);
this.once('finish', () => this._finish());
}
_write(chunk: any, encoding: string, callback: Function): void {
if (!Buffer.isBuffer(chunk)) {
callback(new Error('data must be a buffer'));
}
if (this._decodeStream) {
// just a forwarder now
this._decodeStream.write(chunk, callback);
return;
}
this._buffer.push(chunk);
this._bytesBuffered += chunk.length;
if (this._decodeStreamConstruction) {
// waiting for the decoder to be ready
this._decodeStreamConstruction.then(_ => callback(), err => callback(err));
} else if (this._bytesBuffered >= options.minBytesRequiredForDetection) {
// buffered enough data, create stream and forward data
this._startDecodeStream(callback);
} else {
// only buffering
callback();
}
}
_startDecodeStream(callback: Function): void {
this._decodeStreamConstruction = TPromise.as(detectEncodingFromBuffer({
buffer: Buffer.concat(this._buffer), bytesRead: this._bytesBuffered
}, options.guessEncoding)).then(detected => {
detected.encoding = options.overwriteEncoding(detected.encoding);
this._decodeStream = decodeStream(detected.encoding);
for (const buffer of this._buffer) {
this._decodeStream.write(buffer);
}
callback();
resolve({ detected, stream: this._decodeStream });
}, err => {
this.emit('error', err);
callback(err);
});
}
_finish(): void {
if (this._decodeStream) {
// normal finish
this._decodeStream.end();
} else {
// we were still waiting for data...
this._startDecodeStream(() => this._decodeStream.end());
}
}
});
});
}
export function bomLength(encoding: string): number {
switch (encoding) {
case UTF8:
return 3;
case UTF16be:
case UTF16le:
return 2;
}
return 0;
}
export function decode(buffer: NodeBuffer, encoding: string): string {
return iconv.decode(buffer, toNodeEncoding(encoding));
}
export function encode(content: string | NodeBuffer, encoding: string, options?: { addBOM?: boolean }): NodeBuffer {
return iconv.encode(content, toNodeEncoding(encoding), options);
}
export function encodingExists(encoding: string): boolean {
return iconv.encodingExists(toNodeEncoding(encoding));
}
export function decodeStream(encoding: string): NodeJS.ReadWriteStream {
return iconv.decodeStream(toNodeEncoding(encoding));
}
export function encodeStream(encoding: string, options?: { addBOM?: boolean }): NodeJS.ReadWriteStream {
return iconv.encodeStream(toNodeEncoding(encoding), options);
}
function toNodeEncoding(enc: string): string {
if (enc === UTF8_with_bom) {
return UTF8; // iconv does not distinguish UTF 8 with or without BOM, so we need to help it
}
return enc;
}
export function detectEncodingByBOMFromBuffer(buffer: NodeBuffer, bytesRead: number): string {
if (!buffer || bytesRead < 2) {
return null;
}
const b0 = buffer.readUInt8(0);
const b1 = buffer.readUInt8(1);
// UTF-16 BE
if (b0 === 0xFE && b1 === 0xFF) {
return UTF16be;
}
// UTF-16 LE
if (b0 === 0xFF && b1 === 0xFE) {
return UTF16le;
}
if (bytesRead < 3) {
return null;
}
const b2 = buffer.readUInt8(2);
// UTF-8
if (b0 === 0xEF && b1 === 0xBB && b2 === 0xBF) {
return UTF8;
}
return null;
}
/**
* Detects the Byte Order Mark in a given file.
* If no BOM is detected, null will be passed to callback.
*/
export function detectEncodingByBOM(file: string): TPromise<string> {
return stream.readExactlyByFile(file, 3).then(({ buffer, bytesRead }) => detectEncodingByBOMFromBuffer(buffer, bytesRead));
}
const MINIMUM_THRESHOLD = 0.2;
const IGNORE_ENCODINGS = ['ascii', 'utf-8', 'utf-16', 'utf-32'];
/**
* Guesses the encoding from buffer.
*/
export function guessEncodingByBuffer(buffer: NodeBuffer): TPromise<string> {
return asWinJSImport(import('jschardet')).then(jschardet => {
jschardet.Constants.MINIMUM_THRESHOLD = MINIMUM_THRESHOLD;
const guessed = jschardet.detect(buffer);
if (!guessed || !guessed.encoding) {
return null;
}
const enc = guessed.encoding.toLowerCase();
// Ignore encodings that cannot guess correctly
// (http://chardet.readthedocs.io/en/latest/supported-encodings.html)
if (0 <= IGNORE_ENCODINGS.indexOf(enc)) {
return null;
}
return toIconvLiteEncoding(guessed.encoding);
});
}
const JSCHARDET_TO_ICONV_ENCODINGS: { [name: string]: string } = {
'ibm866': 'cp866',
'big5': 'cp950'
};
function toIconvLiteEncoding(encodingName: string): string {
const normalizedEncodingName = encodingName.replace(/[^a-zA-Z0-9]/g, '').toLowerCase();
const mapped = JSCHARDET_TO_ICONV_ENCODINGS[normalizedEncodingName];
return mapped || normalizedEncodingName;
}
/**
* The encodings that are allowed in a settings file don't match the canonical encoding labels specified by WHATWG.
* See https://encoding.spec.whatwg.org/#names-and-labels
* Iconv-lite strips all non-alphanumeric characters, but ripgrep doesn't. For backcompat, allow these labels.
*/
export function toCanonicalName(enc: string): string {
switch (enc) {
case 'shiftjis':
return 'shift-jis';
case 'utf16le':
return 'utf-16le';
case 'utf16be':
return 'utf-16be';
case 'big5hkscs':
return 'big5-hkscs';
case 'eucjp':
return 'euc-jp';
case 'euckr':
return 'euc-kr';
case 'koi8r':
return 'koi8-r';
case 'koi8u':
return 'koi8-u';
case 'macroman':
return 'x-mac-roman';
case 'utf8bom':
return 'utf8';
default:
const m = enc.match(/windows(\d+)/);
if (m) {
return 'windows-' + m[1];
}
return enc;
}
}
const ZERO_BYTE_DETECTION_BUFFER_MAX_LEN = 512; // number of bytes to look at to decide about a file being binary or not
const NO_GUESS_BUFFER_MAX_LEN = 512; // when not auto guessing the encoding, small number of bytes are enough
const AUTO_GUESS_BUFFER_MAX_LEN = 512 * 8; // with auto guessing we want a lot more content to be read for guessing
export interface IDetectedEncodingResult {
encoding: string;
seemsBinary: boolean;
}
export interface DetectEncodingOption {
autoGuessEncoding?: boolean;
}
export function detectEncodingFromBuffer(readResult: stream.ReadResult, autoGuessEncoding?: false): IDetectedEncodingResult;
export function detectEncodingFromBuffer(readResult: stream.ReadResult, autoGuessEncoding?: boolean): TPromise<IDetectedEncodingResult>;
export function detectEncodingFromBuffer({ buffer, bytesRead }: stream.ReadResult, autoGuessEncoding?: boolean): TPromise<IDetectedEncodingResult> | IDetectedEncodingResult {
// Always first check for BOM to find out about encoding
let encoding = detectEncodingByBOMFromBuffer(buffer, bytesRead);
// Detect 0 bytes to see if file is binary or UTF-16 LE/BE
// unless we already know that this file has a UTF-16 encoding
let seemsBinary = false;
if (encoding !== UTF16be && encoding !== UTF16le) {
let couldBeUTF16LE = true; // e.g. 0xAA 0x00
let couldBeUTF16BE = true; // e.g. 0x00 0xAA
let containsZeroByte = false;
// This is a simplified guess to detect UTF-16 BE or LE by just checking if
// the first 512 bytes have the 0-byte at a specific location. For UTF-16 LE
// this would be the odd byte index and for UTF-16 BE the even one.
// Note: this can produce false positives (a binary file that uses a 2-byte
// encoding of the same format as UTF-16) and false negatives (a UTF-16 file
// that is using 4 bytes to encode a character).
for (let i = 0; i < bytesRead && i < ZERO_BYTE_DETECTION_BUFFER_MAX_LEN; i++) {
const isEndian = (i % 2 === 1); // assume 2-byte sequences typical for UTF-16
const isZeroByte = (buffer.readInt8(i) === 0);
if (isZeroByte) {
containsZeroByte = true;
}
// UTF-16 LE: expect e.g. 0xAA 0x00
if (couldBeUTF16LE && (isEndian && !isZeroByte || !isEndian && isZeroByte)) {
couldBeUTF16LE = false;
}
// UTF-16 BE: expect e.g. 0x00 0xAA
if (couldBeUTF16BE && (isEndian && isZeroByte || !isEndian && !isZeroByte)) {
couldBeUTF16BE = false;
}
// Return if this is neither UTF16-LE nor UTF16-BE and thus treat as binary
if (isZeroByte && !couldBeUTF16LE && !couldBeUTF16BE) {
break;
}
}
// Handle case of 0-byte included
if (containsZeroByte) {
if (couldBeUTF16LE) {
encoding = UTF16le;
} else if (couldBeUTF16BE) {
encoding = UTF16be;
} else {
seemsBinary = true;
}
}
}
// Auto guess encoding if configured
if (autoGuessEncoding && !seemsBinary && !encoding) {
return guessEncodingByBuffer(buffer.slice(0, bytesRead)).then(encoding => {
return {
seemsBinary: false,
encoding
};
});
}
return { seemsBinary, encoding };
}
// https://ss64.com/nt/chcp.html
const windowsTerminalEncodings = {
'437': 'cp437', // United States
'850': 'cp850', // Multilingual(Latin I)
'852': 'cp852', // Slavic(Latin II)
'855': 'cp855', // Cyrillic(Russian)
'857': 'cp857', // Turkish
'860': 'cp860', // Portuguese
'861': 'cp861', // Icelandic
'863': 'cp863', // Canadian - French
'865': 'cp865', // Nordic
'866': 'cp866', // Russian
'869': 'cp869', // Modern Greek
'936': 'cp936', // Simplified Chinese
'1252': 'cp1252' // West European Latin
};
export function resolveTerminalEncoding(verbose?: boolean): TPromise<string> {
let rawEncodingPromise: TPromise<string>;
// Support a global environment variable to win over other mechanics
const cliEncodingEnv = process.env['VSCODE_CLI_ENCODING'];
if (cliEncodingEnv) {
if (verbose) {
console.log(`Found VSCODE_CLI_ENCODING variable: ${cliEncodingEnv}`);
}
rawEncodingPromise = TPromise.as(cliEncodingEnv);
}
// Linux/Mac: use "locale charmap" command
else if (isLinux || isMacintosh) {
rawEncodingPromise = new TPromise<string>(c => {
if (verbose) {
console.log('Running "locale charmap" to detect terminal encoding...');
}
exec('locale charmap', (err, stdout, stderr) => c(stdout));
});
}
// Windows: educated guess
else {
rawEncodingPromise = new TPromise<string>(c => {
if (verbose) {
console.log('Running "chcp" to detect terminal encoding...');
}
exec('chcp', (err, stdout, stderr) => {
if (stdout) {
const windowsTerminalEncodingKeys = Object.keys(windowsTerminalEncodings);
for (let i = 0; i < windowsTerminalEncodingKeys.length; i++) {
const key = windowsTerminalEncodingKeys[i];
if (stdout.indexOf(key) >= 0) {
return c(windowsTerminalEncodings[key]);
}
}
}
return c(void 0);
});
});
}
return rawEncodingPromise.then(rawEncoding => {
if (verbose) {
console.log(`Detected raw terminal encoding: ${rawEncoding}`);
}
if (!rawEncoding || rawEncoding.toLowerCase() === 'utf-8' || rawEncoding.toLowerCase() === UTF8) {
return UTF8;
}
const iconvEncoding = toIconvLiteEncoding(rawEncoding);
if (iconv.encodingExists(iconvEncoding)) {
return iconvEncoding;
}
if (verbose) {
console.log('Unsupported terminal encoding, falling back to UTF-8.');
}
return UTF8;
});
}