Add xterm.js 2.1.0 and a wrapper class to the asset pipeline

app/assets/javascripts/terminal/terminal.js.es6

+/* global Terminal */
+
+(() => {
+  class GLTerminal {
+
+    constructor(options) {
+      this.options = options || {};
+
+      this.options.cursorBlink = options.cursorBlink || true;
+      this.options.screenKeys = options.screenKeys || true;
+      this.container = document.querySelector(options.selector);
+
+      this.setSocketUrl();
+      this.createTerminal();
+      $(window).off('resize.terminal').on('resize.terminal', () => {
+        this.terminal.fit();
+      });
+    }
+
+    setSocketUrl() {
+      const { protocol, hostname, port } = window.location;
+      const wsProtocol = protocol === 'https:' ? 'wss://' : 'ws://';
+      const path = this.container.dataset.projectPath;
+
+      this.socketUrl = `${wsProtocol}${hostname}:${port}${path}`;
+    }
+
+    createTerminal() {
+      this.terminal = new Terminal(this.options);
+      this.socket = new WebSocket(this.socketUrl, ['terminal.gitlab.com']);
+      this.socket.binaryType = 'arraybuffer';
+
+      this.terminal.open(this.container);
+      this.socket.onopen = () => { this.runTerminal(); };
+      this.socket.onerror = () => { this.handleSocketFailure(); };
+    }
+
+    runTerminal() {
+      const decoder = new TextDecoder('utf-8');
+      const encoder = new TextEncoder('utf-8');
+
+      this.terminal.on('data', (data) => {
+        this.socket.send(encoder.encode(data));
+      });
+
+      this.socket.addEventListener('message', (ev) => {
+        this.terminal.write(decoder.decode(ev.data));
+      });
+
+      this.isTerminalInitialized = true;
+      this.terminal.fit();
+    }
+
+    handleSocketFailure() {
+      this.terminal.write('\r\nConnection failure');
+    }
+
+  }
+
+  window.gl = window.gl || {};
+  gl.Terminal = GLTerminal;
+})();

app/assets/javascripts/terminal/terminal_bundle.js.es6

+//= require xterm/xterm.js
+//= require xterm/fit.js
+//= require ./terminal.js
+
+$(() => new gl.Terminal({ selector: '#terminal' }));

config/application.rb

@@ -89,6 +89,7 @@ module Gitlab
     config.assets.precompile << "mailers/*.css"
     config.assets.precompile << "katex.css"
     config.assets.precompile << "katex.js"
+    config.assets.precompile << "xterm/xterm.css"
     config.assets.precompile << "graphs/graphs_bundle.js"
     config.assets.precompile << "users/users_bundle.js"
     config.assets.precompile << "network/network_bundle.js"
@@ -102,6 +103,7 @@ module Gitlab
     config.assets.precompile << "environments/environments_bundle.js"
     config.assets.precompile << "blob_edit/blob_edit_bundle.js"
     config.assets.precompile << "snippet/snippet_bundle.js"
+    config.assets.precompile << "terminal/terminal_bundle.js"
     config.assets.precompile << "lib/utils/*.js"
     config.assets.precompile << "lib/*.js"
     config.assets.precompile << "u2f.js"

vendor/assets/javascripts/xterm/fit.js

+/*
+ *  Fit terminal columns and rows to the dimensions of its
+ *  DOM element.
+ *
+ *  Approach:
+ *    - Rows: Truncate the division of the terminal parent element height
+ *            by the terminal row height
+ *
+ *    - Columns: Truncate the division of the terminal parent element width by
+ *               the terminal character width (apply display: inline at the
+ *               terminal row and truncate its width with the current number
+ *               of columns)
+ */
+(function (fit) {
+  if (typeof exports === 'object' && typeof module === 'object') {
+    /*
+     * CommonJS environment
+     */
+    module.exports = fit(require('../../xterm'));
+  } else if (typeof define == 'function') {
+    /*
+     * Require.js is available
+     */
+    define(['../../xterm'], fit);
+  } else {
+    /*
+     * Plain browser environment
+     */
+    fit(window.Terminal);
+  }
+})(function (Xterm) {
+  /**
+   * This module provides methods for fitting a terminal's size to a parent container.
+   *
+   * @module xterm/addons/fit/fit
+   */
+  var exports = {};
+
+  exports.proposeGeometry = function (term) {
+    var parentElementStyle = window.getComputedStyle(term.element.parentElement),
+        parentElementHeight = parseInt(parentElementStyle.getPropertyValue('height')),
+        parentElementWidth = parseInt(parentElementStyle.getPropertyValue('width')),
+        elementStyle = window.getComputedStyle(term.element),
+        elementPaddingVer = parseInt(elementStyle.getPropertyValue('padding-top')) + parseInt(elementStyle.getPropertyValue('padding-bottom')),
+        elementPaddingHor = parseInt(elementStyle.getPropertyValue('padding-right')) + parseInt(elementStyle.getPropertyValue('padding-left')),
+        availableHeight = parentElementHeight - elementPaddingVer,
+        availableWidth = parentElementWidth - elementPaddingHor,
+        container = term.rowContainer,
+        subjectRow = term.rowContainer.firstElementChild,
+        contentBuffer = subjectRow.innerHTML,
+        characterHeight,
+        rows,
+        characterWidth,
+        cols,
+        geometry;
+
+    subjectRow.style.display = 'inline';
+    subjectRow.innerHTML = 'W'; // Common character for measuring width, although on monospace
+    characterWidth = subjectRow.getBoundingClientRect().width;
+    subjectRow.style.display = ''; // Revert style before calculating height, since they differ.
+    characterHeight = parseInt(subjectRow.offsetHeight);
+    subjectRow.innerHTML = contentBuffer;
+
+    rows = parseInt(availableHeight / characterHeight);
+    cols = parseInt(availableWidth / characterWidth) - 1;
+
+    geometry = {cols: cols, rows: rows};
+    return geometry;
+  };
+
+  exports.fit = function (term) {
+    var geometry = exports.proposeGeometry(term);
+
+    term.resize(geometry.cols, geometry.rows);
+  };
+
+  Xterm.prototype.proposeGeometry = function () {
+    return exports.proposeGeometry(this);
+  };
+
+  Xterm.prototype.fit = function () {
+    return exports.fit(this);
+  };
+
+  return exports;
+});