fix #36951

src/vs/base/node/encoding.ts

@@ -19,6 +19,7 @@ export const UTF16le = 'utf16le';
 
 export interface IDecodeStreamOptions {
 	guessEncoding?: boolean;
+	restrictGuessedEncodings?: string[];
 	minBytesRequiredForDetection?: number;
 	overwriteEncoding?(detectedEncoding: string): string;
 }
@@ -78,7 +79,7 @@ export function toDecodeStream(readable: Readable, options: IDecodeStreamOptions
 
 				this._decodeStreamConstruction = TPromise.as(detectEncodingFromBuffer({
 					buffer: Buffer.concat(this._buffer), bytesRead: this._bytesBuffered
-				}, options.guessEncoding)).then(detected => {
+				}, options.guessEncoding, options.restrictGuessedEncodings)).then(detected => {
 					detected.encoding = options.overwriteEncoding(detected.encoding);
 					this._decodeStream = decodeStream(detected.encoding);
 					for (const buffer of this._buffer) {
@@ -271,13 +272,9 @@ export interface IDetectedEncodingResult {
 	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 {
+export function detectEncodingFromBuffer(readResult: stream.ReadResult, autoGuessEncoding?: boolean, restrictGuessedEncodings?: string[]): TPromise<IDetectedEncodingResult>;
+export function detectEncodingFromBuffer({ buffer, bytesRead }: stream.ReadResult, autoGuessEncoding?: boolean, restrictGuessedEncodings?: string[]): TPromise<IDetectedEncodingResult> | IDetectedEncodingResult {
 
 	// Always first check for BOM to find out about encoding
 	let encoding = detectEncodingByBOMFromBuffer(buffer, bytesRead);
@@ -334,10 +331,17 @@ export function detectEncodingFromBuffer({ buffer, bytesRead }: stream.ReadResul
 
 	// Auto guess encoding if configured
 	if (autoGuessEncoding && !seemsBinary && !encoding) {
-		return guessEncodingByBuffer(buffer.slice(0, bytesRead)).then(encoding => {
+		return guessEncodingByBuffer(buffer.slice(0, bytesRead)).then(guessedEncoding => {
+
+			// Ignore encoding if we have a list of encodings to use for guessing
+			if (guessedEncoding && restrictGuessedEncodings && restrictGuessedEncodings.length > 0 && restrictGuessedEncodings.indexOf(guessedEncoding) === -1) {
+				return { seemsBinary, encoding };
+			}
+
+			// Proceed with guessed encoding
 			return {
 				seemsBinary: false,
-				encoding
+				encoding: guessedEncoding
 			};
 		});
 	}

src/vs/base/test/node/encoding/encoding.test.ts

@@ -153,6 +153,42 @@ suite('Encoding', () => {
 		});
 	});
 
+	test('autoGuessEncoding, restrictGuessedEncodings empty (ShiftJIS)', function () {
+		const file = getPathFromAmdModule(require, './fixtures/some.shiftjis.txt');
+		return readExactlyByFile(file, 512 * 8).then(buffer => {
+			return encoding.detectEncodingFromBuffer(buffer, true, []).then(mimes => {
+				assert.equal(mimes.encoding, 'shiftjis');
+			});
+		});
+	});
+
+	test('autoGuessEncoding, restrictGuessedEncodings (ShiftJIS)', function () {
+		const file = getPathFromAmdModule(require, './fixtures/some.shiftjis.txt');
+		return readExactlyByFile(file, 512 * 8).then(buffer => {
+			return encoding.detectEncodingFromBuffer(buffer, true, ['windows1252']).then(mimes => {
+				assert.ok(!mimes.encoding);
+			});
+		});
+	});
+
+	test('autoGuessEncoding, restrictGuessedEncodings (ShiftJIS)', function () {
+		const file = getPathFromAmdModule(require, './fixtures/some.shiftjis.txt');
+		return readExactlyByFile(file, 512 * 8).then(buffer => {
+			return encoding.detectEncodingFromBuffer(buffer, true, ['windows1252', 'shiftjis']).then(mimes => {
+				assert.equal(mimes.encoding, 'shiftjis');
+			});
+		});
+	});
+
+	test('autoGuessEncoding, restrictGuessedEncodings (CP1252)', function () {
+		const file = getPathFromAmdModule(require, './fixtures/some.cp1252.txt');
+		return readExactlyByFile(file, 512 * 8).then(buffer => {
+			return encoding.detectEncodingFromBuffer(buffer, true, ['windows1252']).then(mimes => {
+				assert.equal(mimes.encoding, 'windows1252');
+			});
+		});
+	});
+
 	async function readAndDecodeFromDisk(path, _encoding) {
 		return new Promise<string>((resolve, reject) => {
 			fs.readFile(path, (err, data) => {

src/vs/platform/files/common/files.ts

@@ -552,6 +552,12 @@ export interface IResolveContentOptions {
 	 */
 	autoGuessEncoding?: boolean;
 
+	/**
+	 * The optional list of encodings that can be used when guessing. If not provided, all encodings
+	 * will be supported for guessing.
+	 */
+	restrictGuessedEncodings?: string[];
+
 	/**
 	 * Is an integer specifying where to begin reading from in the file. If position is null,
 	 * data will be read from the current file position.
@@ -661,6 +667,7 @@ export interface IFilesConfiguration {
 		watcherExclude: { [filepattern: string]: boolean };
 		encoding: string;
 		autoGuessEncoding: boolean;
+		restrictGuessedEncodings: string[];
 		defaultLanguage: string;
 		trimTrailingWhitespace: boolean;
 		autoSave: string;

src/vs/platform/telemetry/common/telemetryUtils.ts

@@ -163,6 +163,7 @@ const configurationValueWhitelist = [
 	'extensions.autoUpdate',
 	'files.associations',
 	'files.autoGuessEncoding',
+	'files.restrictGuessedEncodings',
 	'files.autoSave',
 	'files.autoSaveDelay',
 	'files.encoding',

src/vs/workbench/parts/files/electron-browser/files.contribution.ts

@@ -234,6 +234,17 @@ configurationRegistry.registerConfiguration({
 			'description': nls.localize('autoGuessEncoding', "When enabled, the editor will attempt to guess the character set encoding when opening files. This setting can also be configured per language."),
 			'scope': ConfigurationScope.RESOURCE
 		},
+		'files.restrictGuessedEncodings': {
+			'type': 'array',
+			'overridable': true,
+			'default': [],
+			'items': {
+				'type': 'string',
+				'enum': Object.keys(SUPPORTED_ENCODINGS)
+			},
+			'scope': ConfigurationScope.RESOURCE,
+			'description': nls.localize('restrictGuessedEncodings', "If provided, will restrict the list of encodings that can be used when guessing. If the guessed file encoding is not in the list, the default encoding will be used.")
+		},
 		'files.eol': {
 			'type': 'string',
 			'enum': [

src/vs/workbench/services/files/electron-browser/fileService.ts

@@ -529,10 +529,10 @@ export class FileService extends Disposable implements IFileService {
 						} else {
 							// when receiving the first chunk of data we need to create the
 							// decoding stream which is then used to drive the string stream.
-							const autoGuessEncoding = (options && options.autoGuessEncoding) || this.textResourceConfigurationService.getValue(resource, 'files.autoGuessEncoding');
 							TPromise.as(encoding.detectEncodingFromBuffer(
 								{ buffer: chunkBuffer, bytesRead },
-								autoGuessEncoding
+								(options && options.autoGuessEncoding) || this.textResourceConfigurationService.getValue(resource, 'files.autoGuessEncoding'),
+								(options && options.restrictGuessedEncodings) || this.textResourceConfigurationService.getValue(resource, 'files.restrictGuessedEncodings')
 							)).then(detected => {
 
 								if (options && options.acceptTextOnly && detected.seemsBinary) {

src/vs/workbench/services/files/electron-browser/remoteFileService.ts

@@ -374,6 +374,7 @@ export class RemoteFileService extends FileService {
 
 				const decodeStreamOpts: IDecodeStreamOptions = {
 					guessEncoding: options.autoGuessEncoding,
+					restrictGuessedEncodings: options.restrictGuessedEncodings,
 					overwriteEncoding: detected => {
 						return this.encoding.getReadEncoding(resource, options, { encoding: detected, seemsBinary: false });
 					}