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[api-major] Only create a StatTimer for pages when enableStats == true (issue 5215)

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Unless the debugging tools (i.e. `PDFBug`) are enabled, or the `browsertest` is running, the `PDFPageProxy.stats` aren't actually used for anything.
Rather than initializing unnecessary `StatTimer` instances, we can simply re-use *one* dummy class (with static methods) for every page. Note that by using a dummy `StatTimer` in this way, rather than letting `PDFPageProxy.stats` be undefined, we don't need to guard *every* single stats collection callsite.

Since it wouldn't make much sense to attempt to use `PDFPageProxy.stats` when stat collection is disabled, it was instead changed to a "private" property (i.e. `PDFPageProxy._stats`) and a getter was added for accessing `PDFPageProxy.stats`. This getter will now return `null` when stat collection is disabled, making that case easy to handle.

For benchmarking purposes, the test-suite used to re-create the `StatTimer` after loading/rendering each page. However, modifying properties on various API code from the outside in this way seems very error-prone, and is an anti-pattern that we really should avoid at all cost. Hence the `PDFPageProxy.cleanup` method was modified to accept an optional parameter, which will take care of resetting `this.stats` when necessary, and `test/driver.js` was updated accordingly.

Finally, a tiny bit more validation was added on the viewer side, to ensure that all the code we're attempting to access is defined when handling `PDFPageProxy` stats.
This commit is contained in:
Jonas Jenwald 2017-12-06 16:30:04 +01:00
parent 50b72dec6e
commit 7c5ba9aad5
5 changed files with 59 additions and 19 deletions
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30
src/display/api.js
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@ -21,7 +21,7 @@ import {
stringToBytes, UnexpectedResponseException, UnknownErrorException, Util, warn
} from '../shared/util';
import {
DOMCanvasFactory, DOMCMapReaderFactory, getDefaultSetting,
DOMCanvasFactory, DOMCMapReaderFactory, DummyStatTimer, getDefaultSetting,
RenderingCancelledException, StatTimer
} from './dom_utils';
import { FontFaceObject, FontLoader } from './font_loader';
@ -734,8 +734,8 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
this.pageIndex = pageIndex;
this.pageInfo = pageInfo;
this.transport = transport;
this.stats = new StatTimer();
this.stats.enabled = getDefaultSetting('enableStats');
this._stats = (getDefaultSetting('enableStats') ?
new StatTimer() : DummyStatTimer);
this.commonObjs = transport.commonObjs;
this.objs = new PDFObjects();
this.cleanupAfterRender = false;
@ -811,7 +811,7 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
* is resolved when the page finishes rendering.
*/
render: function PDFPageProxy_render(params) {
var stats = this.stats;
let stats = this._stats;
stats.time('Overall');
// If there was a pending destroy cancel it so no cleanup happens during
@ -842,7 +842,7 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
lastChunk: false,
};
this.stats.time('Page Request');
stats.time('Page Request');
this.transport.messageHandler.send('RenderPageRequest', {
pageIndex: this.pageNumber - 1,
intent: renderingIntent,
@ -1020,17 +1020,19 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
/**
* Cleans up resources allocated by the page.
* @param {boolean} resetStats - (optional) Reset page stats, if enabled.
* The default value is `false`.
*/
cleanup: function PDFPageProxy_cleanup() {
cleanup(resetStats = false) {
this.pendingCleanup = true;
this._tryCleanup();
this._tryCleanup(resetStats);
},
/**
* For internal use only. Attempts to clean up if rendering is in a state
* where that's possible.
* @ignore
*/
_tryCleanup: function PDFPageProxy_tryCleanup() {
_tryCleanup(resetStats = false) {
if (!this.pendingCleanup ||
Object.keys(this.intentStates).some(function(intent) {
var intentState = this.intentStates[intent];
@ -1045,6 +1047,9 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
}, this);
this.objs.clear();
this.annotationsPromise = null;
if (resetStats) {
this._stats.reset();
}
this.pendingCleanup = false;
},
/**
@ -1086,6 +1091,13 @@ var PDFPageProxy = (function PDFPageProxyClosure() {
this._tryCleanup();
}
},
/**
* @return {Object} Returns page stats, if enabled.
*/
get stats() {
return (this._stats instanceof StatTimer ? this._stats : null);
},
};
return PDFPageProxy;
})();
@ -1704,7 +1716,7 @@ var WorkerTransport = (function WorkerTransportClosure() {
}
var page = this.pageCache[data.pageIndex];
page.stats.timeEnd('Page Request');
page._stats.timeEnd('Page Request');
page._startRenderPage(data.transparency, data.intent);
}, this);