public _updateTokensUntilLine(buffer: ITextBuffer, eventBuilder: ModelTokensChangedEventBuilder, lineNumber: number): void {
		if (!this.tokenizationSupport) {
			this._invalidLineStartIndex = buffer.getLineCount();
			return;
		}

		const linesLength = buffer.getLineCount();
		const endLineIndex = lineNumber - 1;

		// Validate all states up to and including endLineIndex
		for (let lineIndex = this._invalidLineStartIndex; lineIndex <= endLineIndex; lineIndex++) {
			const endStateIndex = lineIndex + 1;
			let r: TokenizationResult2 = null;
			const text = buffer.getLineContent(lineIndex + 1);

			try {
				// Tokenize only the first X characters
				let freshState = this._getState(lineIndex).clone();
				r = this.tokenizationSupport.tokenize2(text, freshState, 0);
			} catch (e) {
				onUnexpectedError(e);
			}

			if (!r) {
				r = nullTokenize2(this.languageIdentifier.id, text, this._getState(lineIndex), 0);
			}
			this._setTokens(this.languageIdentifier.id, lineIndex, text.length, r.tokens);
			eventBuilder.registerChangedTokens(lineIndex + 1);
			this._setIsInvalid(lineIndex, false);

			if (endStateIndex < linesLength) {
				if (this._getState(endStateIndex) !== null && r.endState.equals(this._getState(endStateIndex))) {
					// The end state of this line remains the same
					let nextInvalidLineIndex = lineIndex + 1;
					while (nextInvalidLineIndex < linesLength) {
						if (this._isInvalid(nextInvalidLineIndex)) {
							break;
						}
						if (nextInvalidLineIndex + 1 < linesLength) {
							if (this._getState(nextInvalidLineIndex + 1) === null) {
								break;
							}
						} else {
							if (this._lastState === null) {
								break;
							}
						}
						nextInvalidLineIndex++;
					}
					this._invalidLineStartIndex = Math.max(this._invalidLineStartIndex, nextInvalidLineIndex);
					lineIndex = nextInvalidLineIndex - 1; // -1 because the outer loop increments it
				} else {
					this._setState(endStateIndex, r.endState);
				}
			} else {
				this._lastState = r.endState;
			}
		}
		this._invalidLineStartIndex = Math.max(this._invalidLineStartIndex, endLineIndex + 1);
	}

	public _tokenizeOneLine(buffer: ITextBuffer, eventBuilder: ModelTokensChangedEventBuilder): number {
		if (!this.hasLinesToTokenize(buffer)) {
			return buffer.getLineCount() + 1;
		}
		const lineNumber = this._invalidLineStartIndex + 1;
		this._updateTokensUntilLine(buffer, eventBuilder, lineNumber);
		return lineNumber;
	}

	// #region TextBuffer
	public equals(other: ITextBuffer): boolean {
		if (!(other instanceof PieceTreeTextBuffer)) {
			return false;
		}
		if (this._BOM !== other._BOM) {
			return false;
		}
		if (this.getEOL() !== other.getEOL()) {
			return false;
		}
		return this._pieceTree.equal(other._pieceTree);
	}

	public hasLinesToTokenize(buffer: ITextBuffer): boolean {
		return (this._invalidLineStartIndex < buffer.getLineCount());
	}

export function guessIndentation(source: ITextBuffer, defaultTabSize: number, defaultInsertSpaces: boolean): IGuessedIndentation {
	// Look at most at the first 10k lines
	const linesCount = Math.min(source.getLineCount(), 10000);

	let linesIndentedWithTabsCount = 0;				// number of lines that contain at least one tab in indentation
	let linesIndentedWithSpacesCount = 0;			// number of lines that contain only spaces in indentation

	let previousLineText = '';						// content of latest line that contained non-whitespace chars
	let previousLineIndentation = 0;				// index at which latest line contained the first non-whitespace char

	const ALLOWED_TAB_SIZE_GUESSES = [2, 4, 6, 8, 3, 5, 7];	// prefer even guesses for `tabSize`, limit to [2, 8].
	const MAX_ALLOWED_TAB_SIZE_GUESS = 8;			// max(ALLOWED_TAB_SIZE_GUESSES) = 8

	let spacesDiffCount = [0, 0, 0, 0, 0, 0, 0, 0, 0];		// `tabSize` scores
	let tmp = new SpacesDiffResult();

	for (let lineNumber = 1; lineNumber <= linesCount; lineNumber++) {
		let currentLineLength = source.getLineLength(lineNumber);
		let currentLineText = source.getLineContent(lineNumber);

		// if the text buffer is chunk based, so long lines are cons-string, v8 will flattern the string when we check charCode.
		// checking charCode on chunks directly is cheaper.
		const useCurrentLineText = (currentLineLength <= 65536);

		let currentLineHasContent = false;			// does `currentLineText` contain non-whitespace chars
		let currentLineIndentation = 0;				// index at which `currentLineText` contains the first non-whitespace char
		let currentLineSpacesCount = 0;				// count of spaces found in `currentLineText` indentation
		let currentLineTabsCount = 0;				// count of tabs found in `currentLineText` indentation
		for (let j = 0, lenJ = currentLineLength; j < lenJ; j++) {
			let charCode = (useCurrentLineText ? currentLineText.charCodeAt(j) : source.getLineCharCode(lineNumber, j));

			if (charCode === CharCode.Tab) {
				currentLineTabsCount++;
			} else if (charCode === CharCode.Space) {
				currentLineSpacesCount++;
			} else {
				// Hit non whitespace character on this line
				currentLineHasContent = true;
				currentLineIndentation = j;
				break;
			}
		}

		// Ignore empty or only whitespace lines
		if (!currentLineHasContent) {
			continue;
		}

		if (currentLineTabsCount > 0) {
			linesIndentedWithTabsCount++;
		} else if (currentLineSpacesCount > 1) {
			linesIndentedWithSpacesCount++;
		}

		spacesDiff(previousLineText, previousLineIndentation, currentLineText, currentLineIndentation, tmp);

		if (tmp.looksLikeAlignment) {
			// skip this line entirely
			continue;
		}

		let currentSpacesDiff = tmp.spacesDiff;
		if (currentSpacesDiff <= MAX_ALLOWED_TAB_SIZE_GUESS) {
			spacesDiffCount[currentSpacesDiff]++;
		}

		previousLineText = currentLineText;
		previousLineIndentation = currentLineIndentation;
	}

	let insertSpaces = defaultInsertSpaces;
	if (linesIndentedWithTabsCount !== linesIndentedWithSpacesCount) {
		insertSpaces = (linesIndentedWithTabsCount < linesIndentedWithSpacesCount);
	}

	let tabSize = defaultTabSize;
	let tabSizeScore = (insertSpaces ? 0 : 0.1 * linesCount);

	// console.log("score threshold: " + tabSizeScore);

	ALLOWED_TAB_SIZE_GUESSES.forEach((possibleTabSize) => {
		let possibleTabSizeScore = spacesDiffCount[possibleTabSize];
		if (possibleTabSizeScore > tabSizeScore) {
			tabSizeScore = possibleTabSizeScore;
			tabSize = possibleTabSize;
		}
	});

	// Let a tabSize of 2 win even if it is not the maximum
	// (only in case 4 was guessed)
	if (tabSize === 4 && spacesDiffCount[4] > 0 && spacesDiffCount[2] > 0 && spacesDiffCount[2] >= spacesDiffCount[4] / 2) {
		tabSize = 2;
	}


	// console.log('--------------------------');
	// console.log('linesIndentedWithTabsCount: ' + linesIndentedWithTabsCount + ', linesIndentedWithSpacesCount: ' + linesIndentedWithSpacesCount);
	// console.log('spacesDiffCount: ' + spacesDiffCount);
	// console.log('tabSize: ' + tabSize + ', tabSizeScore: ' + tabSizeScore);

//.........这里部分代码省略.........

export function guessIndentation(source: ITextBuffer, defaultTabSize: number, defaultInsertSpaces: boolean): IGuessedIndentation {
	// Look at most at the first 10k lines
	const linesCount = Math.min(source.getLineCount(), 10000);

	let linesIndentedWithTabsCount = 0;				// number of lines that contain at least one tab in indentation
	let linesIndentedWithSpacesCount = 0;			// number of lines that contain only spaces in indentation

	let previousLineText = '';						// content of latest line that contained non-whitespace chars
	let previousLineIndentation = 0;				// index at which latest line contained the first non-whitespace char

	const ALLOWED_TAB_SIZE_GUESSES = [2, 4, 6, 8];	// limit guesses for `tabSize` to 2, 4, 6 or 8.
	const MAX_ALLOWED_TAB_SIZE_GUESS = 8;			// max(2,4,6,8) = 8

	let spacesDiffCount = [0, 0, 0, 0, 0, 0, 0, 0, 0];		// `tabSize` scores

	for (let lineNumber = 1; lineNumber <= linesCount; lineNumber++) {
		let currentLineLength = source.getLineLength(lineNumber);
		let currentLineText = source.getLineContent(lineNumber);
		let charCodeAt: (offset: number) => number;
		if (currentLineLength > 65536) {
			// if the text buffer is chunk based, so long lines are cons-string, v8 will flattern the string when we check charCode.
			// checking charCode on chunks directly is cheaper.
			charCodeAt = (offset: number) => source.getLineCharCode(lineNumber, offset);
		} else {
			charCodeAt = (offset: number) => currentLineText.charCodeAt(offset);
		}

		let currentLineHasContent = false;			// does `currentLineText` contain non-whitespace chars
		let currentLineIndentation = 0;				// index at which `currentLineText` contains the first non-whitespace char
		let currentLineSpacesCount = 0;				// count of spaces found in `currentLineText` indentation
		let currentLineTabsCount = 0;				// count of tabs found in `currentLineText` indentation
		for (let j = 0, lenJ = currentLineLength; j < lenJ; j++) {
			let charCode = charCodeAt(j);

			if (charCode === CharCode.Tab) {
				currentLineTabsCount++;
			} else if (charCode === CharCode.Space) {
				currentLineSpacesCount++;
			} else {
				// Hit non whitespace character on this line
				currentLineHasContent = true;
				currentLineIndentation = j;
				break;
			}
		}

		// Ignore empty or only whitespace lines
		if (!currentLineHasContent) {
			continue;
		}

		if (currentLineTabsCount > 0) {
			linesIndentedWithTabsCount++;
		} else if (currentLineSpacesCount > 1) {
			linesIndentedWithSpacesCount++;
		}

		let currentSpacesDiff = spacesDiff(previousLineText, previousLineIndentation, currentLineText, currentLineIndentation);
		if (currentSpacesDiff <= MAX_ALLOWED_TAB_SIZE_GUESS) {
			spacesDiffCount[currentSpacesDiff]++;
		}

		previousLineText = currentLineText;
		previousLineIndentation = currentLineIndentation;
	}

	// Take into account the last line as well
	let deltaSpacesCount = spacesDiff(previousLineText, previousLineIndentation, '', 0);
	if (deltaSpacesCount <= MAX_ALLOWED_TAB_SIZE_GUESS) {
		spacesDiffCount[deltaSpacesCount]++;
	}

	let insertSpaces = defaultInsertSpaces;
	if (linesIndentedWithTabsCount !== linesIndentedWithSpacesCount) {
		insertSpaces = (linesIndentedWithTabsCount < linesIndentedWithSpacesCount);
	}

	let tabSize = defaultTabSize;
	let tabSizeScore = (insertSpaces ? 0 : 0.1 * linesCount);

	// console.log("score threshold: " + tabSizeScore);

	ALLOWED_TAB_SIZE_GUESSES.forEach((possibleTabSize) => {
		let possibleTabSizeScore = spacesDiffCount[possibleTabSize];
		if (possibleTabSizeScore > tabSizeScore) {
			tabSizeScore = possibleTabSizeScore;
			tabSize = possibleTabSize;
		}
	});


	// console.log('--------------------------');
	// console.log('linesIndentedWithTabsCount: ' + linesIndentedWithTabsCount + ', linesIndentedWithSpacesCount: ' + linesIndentedWithSpacesCount);
	// console.log('spacesDiffCount: ' + spacesDiffCount);
	// console.log('tabSize: ' + tabSize + ', tabSizeScore: ' + tabSizeScore);

	return {
		insertSpaces: insertSpaces,
		tabSize: tabSize
	};
//.........这里部分代码省略.........

			charCodeAt = (offset: number) => source.getLineCharCode(lineNumber, offset);