Re-factor StatTimer usage, in src/display/api.js, and remove DummyStatTimer

src/display/api.js

@@ -27,8 +27,8 @@ import {
  unreachable, warn
 } from '../shared/util';
 import {
- DOMCanvasFactory, DOMCMapReaderFactory, DummyStatTimer, loadScript,
- PageViewport, releaseImageResources, RenderingCancelledException, StatTimer
+ DOMCanvasFactory, DOMCMapReaderFactory, loadScript, PageViewport,
+ releaseImageResources, RenderingCancelledException, StatTimer
 } from './display_utils';
 import { FontFaceObject, FontLoader } from './font_loader';
 import { apiCompatibilityParams } from './api_compatibility';
@@ -905,7 +905,7 @@ class PDFPageProxy {
  this.pageIndex = pageIndex;
  this._pageInfo = pageInfo;
  this._transport = transport;
- this._stats = (pdfBug ? new StatTimer() : DummyStatTimer);
+ this._stats = (pdfBug ? new StatTimer() : null);
  this._pdfBug = pdfBug;
  this.commonObjs = transport.commonObjs;
  this.objs = new PDFObjects();
@@ -995,8 +995,9 @@ class PDFPageProxy {
  render({ canvasContext, viewport, intent = 'display', enableWebGL = false,
  renderInteractiveForms = false, transform = null, imageLayer = null,
  canvasFactory = null, background = null, }) {
- const stats = this._stats;
- stats.time('Overall');
+ if (this._stats) {
+ this._stats.time('Overall');
+ }
 
  const renderingIntent = (intent === 'print' ? 'print' : 'display');
  // If there was a pending destroy, cancel it so no cleanup happens during
@@ -1029,7 +1030,9 @@ class PDFPageProxy {
  lastChunk: false,
  };
 
- stats.time('Page Request');
+ if (this._stats) {
+ this._stats.time('Page Request');
+ }
  this._pumpOperatorList({
  pageIndex: this.pageNumber - 1,
  intent: renderingIntent,
@@ -1060,8 +1063,10 @@ class PDFPageProxy {
  } else {
  internalRenderTask.capability.resolve();
  }
- stats.timeEnd('Rendering');
- stats.timeEnd('Overall');
+ if (this._stats) {
+ this._stats.timeEnd('Rendering');
+ this._stats.timeEnd('Overall');
+ }
  };
 
  const internalRenderTask = new InternalRenderTask({
@@ -1094,7 +1099,9 @@ class PDFPageProxy {
  complete();
  return;
  }
- stats.time('Rendering');
+ if (this._stats) {
+ this._stats.time('Rendering');
+ }
  internalRenderTask.initializeGraphics(transparency);
  internalRenderTask.operatorListChanged();
  }).catch(complete);
@@ -1137,7 +1144,9 @@ class PDFPageProxy {
  lastChunk: false,
  };
 
- this._stats.time('Page Request');
+ if (this._stats) {
+ this._stats.time('Page Request');
+ }
  this._pumpOperatorList({
  pageIndex: this.pageIndex,
  intent: renderingIntent,
@@ -1259,7 +1268,7 @@ class PDFPageProxy {
  });
  this.objs.clear();
  this.annotationsPromise = null;
- if (resetStats && this._stats instanceof StatTimer) {
+ if (resetStats && this._stats) {
  this._stats = new StatTimer();
  }
  this.pendingCleanup = false;
@@ -1273,7 +1282,9 @@ class PDFPageProxy {
  if (!intentState) {
  return; // Rendering was cancelled.
  }
- this._stats.timeEnd('Page Request');
+ if (this._stats) {
+ this._stats.timeEnd('Page Request');
+ }
  // TODO Refactor RenderPageRequest to separate rendering
  // and operator list logic
  if (intentState.displayReadyCapability) {
@@ -1404,10 +1415,10 @@ class PDFPageProxy {
  }
 
  /**
- * @type {Object} Returns page stats, if enabled.
+ * @type {Object} Returns page stats, if enabled; returns `null` otherwise.
  */
  get stats() {
- return (this._stats instanceof StatTimer ? this._stats : null);
+ return this._stats;
  }
 }
 

src/display/display_utils.js

@@ -16,7 +16,7 @@
 
 import {
  assert, BaseException, CMapCompressionType, isString, removeNullCharacters,
- stringToBytes, unreachable, Util, warn
+ stringToBytes, Util, warn
 } from '../shared/util';
 
 const DEFAULT_LINK_REL = 'noopener noreferrer nofollow';
@@ -380,28 +380,21 @@ function getFilenameFromUrl(url) {
 }
 
 class StatTimer {
- constructor(enable = true) {
- this.enabled = !!enable;
+ constructor() {
  this.started = Object.create(null);
  this.times = [];
  }
 
  time(name) {
- if (!this.enabled) {
- return;
- }
  if (name in this.started) {
- warn('Timer is already running for ' + name);
+ warn(`Timer is already running for ${name}`);
  }
  this.started[name] = Date.now();
  }
 
  timeEnd(name) {
- if (!this.enabled) {
- return;
- }
  if (!(name in this.started)) {
- warn('Timer has not been started for ' + name);
+ warn(`Timer has not been started for ${name}`);
  }
  this.times.push({
  'name': name,
@@ -414,7 +407,7 @@ class StatTimer {
 
  toString() {
  // Find the longest name for padding purposes.
- let out = '', longest = 0;
+ let outBuf = [], longest = 0;
  for (const time of this.times) {
  const name = time.name;
  if (name.length > longest) {
@@ -423,31 +416,9 @@ class StatTimer {
  }
  for (const time of this.times) {
  const duration = time.end - time.start;
- out += `${time.name.padEnd(longest)} ${duration}ms\n`;
+ outBuf.push(`${time.name.padEnd(longest)} ${duration}ms\n`);
  }
- return out;
- }
-}
-
-/**
- * Helps avoid having to initialize {StatTimer} instances, e.g. one for every
- * page, in cases where the collected stats are not actually being used.
- * This (dummy) class can thus, since all its methods are `static`, be directly
- * shared between multiple call-sites without the need to be initialized first.
- *
- * NOTE: This must implement the same interface as {StatTimer}.
- */
-class DummyStatTimer {
- constructor() {
- unreachable('Cannot initialize DummyStatTimer.');
- }
-
- static time(name) {}
-
- static timeEnd(name) {}
-
- static toString() {
- return '';
+ return outBuf.join('');
  }
 }
 
@@ -593,7 +564,6 @@ export {
  DOMCMapReaderFactory,
  DOMSVGFactory,
  StatTimer,
- DummyStatTimer,
  isFetchSupported,
  isValidFetchUrl,
  loadScript,