292 lines
9.2 KiB
TypeScript
292 lines
9.2 KiB
TypeScript
/**
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* Copyright (c) 2017 The xterm.js authors. All rights reserved.
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* @license MIT
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*/
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import { ITerminal, IBuffer } from './Interfaces';
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import { CircularList } from './utils/CircularList';
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import { LineData, CharData } from './Types';
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export const CHAR_DATA_ATTR_INDEX = 0;
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export const CHAR_DATA_CHAR_INDEX = 1;
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export const CHAR_DATA_WIDTH_INDEX = 2;
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export const CHAR_DATA_CODE_INDEX = 3;
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/**
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* This class represents a terminal buffer (an internal state of the terminal), where the
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* following information is stored (in high-level):
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* - text content of this particular buffer
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* - cursor position
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* - scroll position
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*/
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export class Buffer implements IBuffer {
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private _lines: CircularList<LineData>;
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public ydisp: number;
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public ybase: number;
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public y: number;
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public x: number;
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public scrollBottom: number;
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public scrollTop: number;
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public tabs: any;
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public savedY: number;
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public savedX: number;
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/**
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* Create a new Buffer.
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* @param _terminal The terminal the Buffer will belong to.
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* @param _hasScrollback Whether the buffer should respect the scrollback of
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* the terminal.
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*/
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constructor(
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private _terminal: ITerminal,
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private _hasScrollback: boolean
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) {
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this.clear();
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}
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public get lines(): CircularList<LineData> {
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return this._lines;
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}
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public get hasScrollback(): boolean {
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return this._hasScrollback && this.lines.maxLength > this._terminal.rows;
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}
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public get isCursorInViewport(): boolean {
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const absoluteY = this.ybase + this.y;
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const relativeY = absoluteY - this.ydisp;
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return (relativeY >= 0 && relativeY < this._terminal.rows);
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}
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/**
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* Gets the correct buffer length based on the rows provided, the terminal's
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* scrollback and whether this buffer is flagged to have scrollback or not.
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* @param rows The terminal rows to use in the calculation.
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*/
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private _getCorrectBufferLength(rows: number): number {
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if (!this._hasScrollback) {
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return rows;
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}
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return rows + this._terminal.options.scrollback;
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}
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/**
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* Fills the buffer's viewport with blank lines.
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*/
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public fillViewportRows(): void {
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if (this._lines.length === 0) {
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let i = this._terminal.rows;
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while (i--) {
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this.lines.push(this._terminal.blankLine());
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}
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}
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}
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/**
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* Clears the buffer to it's initial state, discarding all previous data.
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*/
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public clear(): void {
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this.ydisp = 0;
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this.ybase = 0;
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this.y = 0;
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this.x = 0;
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this._lines = new CircularList<LineData>(this._getCorrectBufferLength(this._terminal.rows));
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this.scrollTop = 0;
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this.scrollBottom = this._terminal.rows - 1;
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this.setupTabStops();
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}
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/**
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* Resizes the buffer, adjusting its data accordingly.
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* @param newCols The new number of columns.
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* @param newRows The new number of rows.
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*/
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public resize(newCols: number, newRows: number): void {
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// Increase max length if needed before adjustments to allow space to fill
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// as required.
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const newMaxLength = this._getCorrectBufferLength(newRows);
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if (newMaxLength > this._lines.maxLength) {
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this._lines.maxLength = newMaxLength;
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}
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// The following adjustments should only happen if the buffer has been
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// initialized/filled.
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if (this._lines.length > 0) {
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// Deal with columns increasing (we don't do anything when columns reduce)
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if (this._terminal.cols < newCols) {
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const ch: CharData = [this._terminal.defAttr, ' ', 1, 32]; // does xterm use the default attr?
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for (let i = 0; i < this._lines.length; i++) {
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// TODO: This should be removed, with tests setup for the case that was
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// causing the underlying bug, see https://github.com/sourcelair/xterm.js/issues/824
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if (this._lines.get(i) === undefined) {
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this._lines.set(i, this._terminal.blankLine(undefined, undefined, newCols));
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}
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while (this._lines.get(i).length < newCols) {
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this._lines.get(i).push(ch);
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}
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}
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}
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// Resize rows in both directions as needed
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let addToY = 0;
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if (this._terminal.rows < newRows) {
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for (let y = this._terminal.rows; y < newRows; y++) {
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if (this._lines.length < newRows + this.ybase) {
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if (this.ybase > 0 && this._lines.length <= this.ybase + this.y + addToY + 1) {
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// There is room above the buffer and there are no empty elements below the line,
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// scroll up
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this.ybase--;
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addToY++;
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if (this.ydisp > 0) {
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// Viewport is at the top of the buffer, must increase downwards
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this.ydisp--;
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}
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} else {
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// Add a blank line if there is no buffer left at the top to scroll to, or if there
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// are blank lines after the cursor
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this._lines.push(this._terminal.blankLine(undefined, undefined, newCols));
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}
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}
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}
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} else { // (this._terminal.rows >= newRows)
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for (let y = this._terminal.rows; y > newRows; y--) {
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if (this._lines.length > newRows + this.ybase) {
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if (this._lines.length > this.ybase + this.y + 1) {
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// The line is a blank line below the cursor, remove it
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this._lines.pop();
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} else {
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// The line is the cursor, scroll down
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this.ybase++;
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this.ydisp++;
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}
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}
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}
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}
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// Reduce max length if needed after adjustments, this is done after as it
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// would otherwise cut data from the bottom of the buffer.
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if (newMaxLength < this._lines.maxLength) {
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// Trim from the top of the buffer and adjust ybase and ydisp.
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const amountToTrim = this._lines.length - newMaxLength;
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if (amountToTrim > 0) {
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this._lines.trimStart(amountToTrim);
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this.ybase = Math.max(this.ybase - amountToTrim, 0);
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this.ydisp = Math.max(this.ydisp - amountToTrim, 0);
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}
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this._lines.maxLength = newMaxLength;
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}
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// Make sure that the cursor stays on screen
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if (this.y >= newRows) {
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this.y = newRows - 1;
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}
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if (addToY) {
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this.y += addToY;
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}
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if (this.x >= newCols) {
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this.x = newCols - 1;
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}
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this.scrollTop = 0;
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}
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this.scrollBottom = newRows - 1;
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}
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/**
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* Translates a buffer line to a string, with optional start and end columns.
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* Wide characters will count as two columns in the resulting string. This
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* function is useful for getting the actual text underneath the raw selection
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* position.
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* @param line The line being translated.
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* @param trimRight Whether to trim whitespace to the right.
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* @param startCol The column to start at.
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* @param endCol The column to end at.
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*/
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public translateBufferLineToString(lineIndex: number, trimRight: boolean, startCol: number = 0, endCol: number = null): string {
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// Get full line
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let lineString = '';
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let widthAdjustedStartCol = startCol;
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let widthAdjustedEndCol = endCol;
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const line = this.lines.get(lineIndex);
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if (!line) {
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return '';
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}
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for (let i = 0; i < line.length; i++) {
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const char = line[i];
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lineString += char[CHAR_DATA_CHAR_INDEX];
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// Adjust start and end cols for wide characters if they affect their
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// column indexes
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if (char[CHAR_DATA_WIDTH_INDEX] === 0) {
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if (startCol >= i) {
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widthAdjustedStartCol--;
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}
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if (endCol >= i) {
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widthAdjustedEndCol--;
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}
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}
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}
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// Calculate the final end col by trimming whitespace on the right of the
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// line if needed.
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let finalEndCol = widthAdjustedEndCol || line.length;
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if (trimRight) {
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const rightWhitespaceIndex = lineString.search(/\s+$/);
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if (rightWhitespaceIndex !== -1) {
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finalEndCol = Math.min(finalEndCol, rightWhitespaceIndex);
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}
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// Return the empty string if only trimmed whitespace is selected
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if (finalEndCol <= widthAdjustedStartCol) {
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return '';
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}
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}
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return lineString.substring(widthAdjustedStartCol, finalEndCol);
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}
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/**
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* Setup the tab stops.
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* @param i The index to start setting up tab stops from.
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*/
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public setupTabStops(i?: number): void {
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if (i != null) {
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if (!this.tabs[i]) {
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i = this.prevStop(i);
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}
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} else {
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this.tabs = {};
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i = 0;
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}
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for (; i < this._terminal.cols; i += this._terminal.options.tabStopWidth) {
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this.tabs[i] = true;
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}
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}
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/**
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* Move the cursor to the previous tab stop from the given position (default is current).
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* @param x The position to move the cursor to the previous tab stop.
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*/
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public prevStop(x?: number): number {
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if (x == null) {
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x = this.x;
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}
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while (!this.tabs[--x] && x > 0);
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return x >= this._terminal.cols ? this._terminal.cols - 1 : x < 0 ? 0 : x;
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}
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/**
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* Move the cursor one tab stop forward from the given position (default is current).
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* @param x The position to move the cursor one tab stop forward.
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*/
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public nextStop(x?: number): number {
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if (x == null) {
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x = this.x;
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}
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while (!this.tabs[++x] && x < this._terminal.cols);
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return x >= this._terminal.cols ? this._terminal.cols - 1 : x < 0 ? 0 : x;
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}
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}
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