Have common only reference within common

Part of #1337

src/common/CircularList.ts

@@ -3,8 +3,8 @@
  * @license MIT
  */
 
-import { EventEmitter } from '../EventEmitter';
-import { ICircularList } from '../Types';
+import { EventEmitter } from './EventEmitter';
+import { ICircularList } from './Types';
 
 /**
  * Represents a circular list; a list with a maximum size that wraps around when push is called,

src/common/EventEmitter.test.ts

@@ -0,0 +1,77 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { assert } from 'chai';
+import { EventEmitter } from './EventEmitter';
+
+describe('EventEmitter', () => {
+  let eventEmitter: EventEmitter;
+
+  beforeEach(() => {
+    eventEmitter = new EventEmitter();
+  });
+
+  describe('emit', () => {
+    it('should emit events to listeners', () => {
+      let count1 = 0;
+      let count2 = 0;
+      const listener1 = () => count1++;
+      const listener2 = () => count2++;
+      eventEmitter.on('test', listener1);
+      eventEmitter.on('test', listener2);
+      eventEmitter.emit('test');
+      assert.equal(count1, 1);
+      assert.equal(count2, 1);
+      eventEmitter.emit('test');
+      assert.equal(count1, 2);
+      assert.equal(count2, 2);
+    });
+
+    it('should manage multiple listener types', () => {
+      let count1 = 0;
+      let count2 = 0;
+      const listener1 = () => count1++;
+      const listener2 = () => count2++;
+      eventEmitter.on('test', listener1);
+      eventEmitter.on('foo', listener2);
+      eventEmitter.emit('test');
+      assert.equal(count1, 1);
+      assert.equal(count2, 0);
+      eventEmitter.emit('foo');
+      assert.equal(count1, 1);
+      assert.equal(count2, 1);
+    });
+  });
+
+  describe('listeners', () => {
+    it('should return listeners for the type requested', () => {
+      assert.equal(eventEmitter.listeners('test').length, 0);
+      const listener = () => {};
+      eventEmitter.on('test', listener);
+      assert.deepEqual(eventEmitter.listeners('test'), [listener]);
+    });
+  });
+
+  describe('off', () => {
+    it('should remove the specific listener', () => {
+      const listener1 = () => {};
+      const listener2 = () => {};
+      eventEmitter.on('foo', listener1);
+      eventEmitter.on('foo', listener2);
+      assert.equal(eventEmitter.listeners('foo').length, 2);
+      eventEmitter.off('foo', listener1);
+      assert.deepEqual(eventEmitter.listeners('foo'), [listener2]);
+    });
+  });
+
+  describe('removeAllListeners', () => {
+    it('should clear all listeners', () => {
+      eventEmitter.on('foo', () => {});
+      assert.equal(eventEmitter.listeners('foo').length, 1);
+      eventEmitter.removeAllListeners('foo');
+      assert.equal(eventEmitter.listeners('foo').length, 0);
+    });
+  });
+});

src/common/EventEmitter.ts

@@ -0,0 +1,85 @@
+/**
+ * Copyright (c) 2017 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+import { XtermListener } from './Types';
+import { IEventEmitter, IDisposable } from 'xterm';
+import { Disposable } from './Lifecycle';
+
+export class EventEmitter extends Disposable implements IEventEmitter, IDisposable {
+  private _events: {[type: string]: XtermListener[]};
+
+  constructor() {
+    super();
+    // Restore the previous events if available, this will happen if the
+    // constructor is called multiple times on the same object (terminal reset).
+    this._events = this._events || {};
+  }
+
+  public on(type: string, listener: XtermListener): void {
+    this._events[type] = this._events[type] || [];
+    this._events[type].push(listener);
+  }
+
+  /**
+   * Adds a disposabe listener to the EventEmitter, returning the disposable.
+   * @param type The event type.
+   * @param handler The handler for the listener.
+   */
+  public addDisposableListener(type: string, handler: XtermListener): IDisposable {
+    // TODO: Rename addDisposableEventListener to more easily disambiguate from Dom listener
+    this.on(type, handler);
+    return {
+      dispose: () => {
+        if (!handler) {
+          // Already disposed
+          return;
+        }
+        this.off(type, handler);
+        handler = null;
+      }
+    };
+  }
+
+  public off(type: string, listener: XtermListener): void {
+    if (!this._events[type]) {
+      return;
+    }
+
+    const obj = this._events[type];
+    let i = obj.length;
+
+    while (i--) {
+      if (obj[i] === listener) {
+        obj.splice(i, 1);
+        return;
+      }
+    }
+  }
+
+  public removeAllListeners(type: string): void {
+    if (this._events[type]) {
+       delete this._events[type];
+    }
+  }
+
+  public emit(type: string, ...args: any[]): void {
+    if (!this._events[type]) {
+      return;
+    }
+    const obj = this._events[type];
+    for (let i = 0; i < obj.length; i++) {
+      obj[i].apply(this, args);
+    }
+  }
+
+  public listeners(type: string): XtermListener[] {
+    return this._events[type] || [];
+  }
+
+  public dispose(): void {
+    super.dispose();
+    this._events = {};
+  }
+}

src/common/Types.ts

@@ -3,6 +3,10 @@
  * @license MIT
  */
 
+import { IEventEmitter } from 'xterm';
+
+export type XtermListener = (...args: any[]) => void;
+
 /**
  * A keyboard event interface which does not depend on the DOM, KeyboardEvent implicitly extends
  * this event.
@@ -16,3 +20,16 @@ export interface IKeyboardEvent {
   key: string;
   type: string;
 }
+
+export interface ICircularList<T> extends IEventEmitter {
+  length: number;
+  maxLength: number;
+
+  get(index: number): T;
+  set(index: number, value: T): void;
+  push(value: T): void;
+  pop(): T;
+  splice(start: number, deleteCount: number, ...items: T[]): void;
+  trimStart(count: number): void;
+  shiftElements(start: number, count: number, offset: number): void;
+}