CE Port of "Web Terminal FE"

app/assets/javascripts/lib/utils/dom_utils.js

@@ -7,3 +7,8 @@ export const addClassIfElementExists = (element, className) => {
 };
 
 export const isInVueNoteablePage = () => isInIssuePage() || isInEpicPage() || isInMRPage();
+
+export const canScrollUp = ({ scrollTop }, margin = 0) => scrollTop > margin;
+
+export const canScrollDown = ({ scrollTop, offsetHeight, scrollHeight }, margin = 0) =>
+  scrollTop + offsetHeight < scrollHeight - margin;

app/assets/javascripts/terminal/index.js

 import Terminal from './terminal';
 
-export default () => new Terminal({ selector: '#terminal' });
+export default () => new Terminal(document.getElementById('terminal'));

app/assets/javascripts/terminal/terminal.js

+import _ from 'underscore';
 import $ from 'jquery';
 import { Terminal } from 'xterm';
 import * as fit from 'xterm/lib/addons/fit/fit';
+import { canScrollUp, canScrollDown } from '~/lib/utils/dom_utils';
+
+const SCROLL_MARGIN = 5;
+
+Terminal.applyAddon(fit);
 
 export default class GLTerminal {
-  constructor(options = {}) {
+  constructor(element, options = {}) {
     this.options = Object.assign(
       {},
       {
@@ -13,7 +19,8 @@ export default class GLTerminal {
       options,
     );
 
-    this.container = document.querySelector(options.selector);
+    this.container = element;
+    this.onDispose = [];
 
     this.setSocketUrl();
     this.createTerminal();
@@ -34,8 +41,6 @@ export default class GLTerminal {
   }
 
   createTerminal() {
-    Terminal.applyAddon(fit);
-
     this.terminal = new Terminal(this.options);
 
     this.socket = new WebSocket(this.socketUrl, ['terminal.gitlab.com']);
@@ -72,4 +77,48 @@ export default class GLTerminal {
   handleSocketFailure() {
     this.terminal.write('\r\nConnection failure');
   }
+
+  addScrollListener(onScrollLimit) {
+    const viewport = this.container.querySelector('.xterm-viewport');
+    const listener = _.throttle(() => {
+      onScrollLimit({
+        canScrollUp: canScrollUp(viewport, SCROLL_MARGIN),
+        canScrollDown: canScrollDown(viewport, SCROLL_MARGIN),
+      });
+    });
+
+    this.onDispose.push(() => viewport.removeEventListener('scroll', listener));
+    viewport.addEventListener('scroll', listener);
+
+    // don't forget to initialize value before scroll!
+    listener({ target: viewport });
+  }
+
+  disable() {
+    this.terminal.setOption('cursorBlink', false);
+    this.terminal.setOption('theme', { foreground: '#707070' });
+    this.terminal.setOption('disableStdin', true);
+    this.socket.close();
+  }
+
+  dispose() {
+    this.terminal.off('data');
+    this.terminal.dispose();
+    this.socket.close();
+
+    this.onDispose.forEach(fn => fn());
+    this.onDispose.length = 0;
+  }
+
+  scrollToTop() {
+    this.terminal.scrollToTop();
+  }
+
+  scrollToBottom() {
+    this.terminal.scrollToBottom();
+  }
+
+  fit() {
+    this.terminal.fit();
+  }
 }

app/assets/stylesheets/framework/common.scss

@@ -386,3 +386,4 @@ img.emoji {
 .flex-no-shrink { flex-shrink: 0; }
 .mw-460 { max-width: 460px; }
 .ws-initial { white-space: initial; }
+.min-height-0 { min-height: 0; }

app/assets/stylesheets/page_bundles/_ide_mixins.scss

+@mixin ide-trace-view {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+  margin-top: -$grid-size;
+  margin-bottom: -$grid-size;
+
+  &.build-page .top-bar {
+    top: 0;
+    height: auto;
+    font-size: 12px;
+    border-top-right-radius: $border-radius-default;
+  }
+
+  .top-bar {
+    margin-left: -$gl-padding;
+  }
+}

app/assets/stylesheets/page_bundles/ide.scss

 @import 'framework/variables';
 @import 'framework/mixins';
+@import './ide_mixins';
 
 $search-list-icon-width: 18px;
 $ide-activity-bar-width: 60px;
@@ -1111,11 +1112,7 @@ $ide-commit-header-height: 48px;
 }
 
 .ide-pipeline {
-  display: flex;
-  flex-direction: column;
-  height: 100%;
-  margin-top: -$grid-size;
-  margin-bottom: -$grid-size;
+  @include ide-trace-view();
 
   .empty-state {
     margin-top: auto;
@@ -1133,17 +1130,9 @@ $ide-commit-header-height: 48px;
     }
   }
 
-  .build-trace,
-  .top-bar {
+  .build-trace {
     margin-left: -$gl-padding;
   }
-
-  &.build-page .top-bar {
-    top: 0;
-    height: auto;
-    font-size: 12px;
-    border-top-right-radius: $border-radius-default;
-  }
 }
 
 .ide-pipeline-list {

spec/javascripts/lib/utils/dom_utils_spec.js

-import { addClassIfElementExists } from '~/lib/utils/dom_utils';
+import { addClassIfElementExists, canScrollUp, canScrollDown } from '~/lib/utils/dom_utils';
+
+const TEST_MARGIN = 5;
 
 describe('DOM Utils', () => {
   describe('addClassIfElementExists', () => {
@@ -34,4 +36,54 @@ describe('DOM Utils', () => {
       addClassIfElementExists(childElement, className);
     });
   });
+
+  describe('canScrollUp', () => {
+    [1, 100].forEach(scrollTop => {
+      it(`is true if scrollTop is > 0 (${scrollTop})`, () => {
+        expect(canScrollUp({ scrollTop })).toBe(true);
+      });
+    });
+
+    [0, -10].forEach(scrollTop => {
+      it(`is false if scrollTop is <= 0 (${scrollTop})`, () => {
+        expect(canScrollUp({ scrollTop })).toBe(false);
+      });
+    });
+
+    it('is true if scrollTop is > margin', () => {
+      expect(canScrollUp({ scrollTop: TEST_MARGIN + 1 }, TEST_MARGIN)).toBe(true);
+    });
+
+    it('is false if scrollTop is <= margin', () => {
+      expect(canScrollUp({ scrollTop: TEST_MARGIN }, TEST_MARGIN)).toBe(false);
+    });
+  });
+
+  describe('canScrollDown', () => {
+    let element;
+
+    beforeEach(() => {
+      element = { scrollTop: 7, offsetHeight: 22, scrollHeight: 30 };
+    });
+
+    it('is true if element can be scrolled down', () => {
+      expect(canScrollDown(element)).toBe(true);
+    });
+
+    it('is false if element cannot be scrolled down', () => {
+      element.scrollHeight -= 1;
+
+      expect(canScrollDown(element)).toBe(false);
+    });
+
+    it('is true if element can be scrolled down, with margin given', () => {
+      element.scrollHeight += TEST_MARGIN;
+
+      expect(canScrollDown(element, TEST_MARGIN)).toBe(true);
+    });
+
+    it('is false if element cannot be scrolled down, with margin given', () => {
+      expect(canScrollDown(element, TEST_MARGIN)).toBe(false);
+    });
+  });
 });