From 8eed0b9145acab83094ddf0e41bfcd5c88d9f996 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 11 Nov 2021 12:36:06 +0100
Subject: [PATCH] Report "pageInfo" telemetry once, rather than for each
 rendered page

Reporting telemetry, in Firefox, includes using `JSON.stringify` on the data and then sending an event to the `PdfStreamConverter.jsm`-code.
In that code the event is handled and `JSON.parse` is used to retrieve the data, and in the "pageInfo"-case we'll then proceed to ignore everything except *the first* such event; see https://searchfox.org/mozilla-central/rev/24fac1ad31fb9c6e9c4c767c6a7ff45d226078f3/toolkit/components/pdfjs/content/PdfStreamConverter.jsm#509-514

All-in-all, sending the "pageInfo" telemetry for each rendered page is thus unnecessary and this patch makes the viewer send it only *once* instead.
---
 web/app.js         | 13 +++++++------
 web/base_viewer.js |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/web/app.js b/web/app.js
index 28a9d5969..2715fd188 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1372,7 +1372,12 @@ const PDFViewerApplication = {
       this._initializeAutoPrint(pdfDocument, openActionPromise);
     });
 
-    onePageRendered.then(() => {
+    onePageRendered.then(data => {
+      this.externalServices.reportTelemetry({
+        type: "pageInfo",
+        timestamp: data.timestamp,
+      });
+
       pdfDocument.getOutline().then(outline => {
         if (pdfDocument !== this.pdfDocument) {
           return; // The document was closed while the outline resolved.
@@ -2315,7 +2320,7 @@ function webViewerResetPermissions() {
   appConfig.viewerContainer.classList.remove(ENABLE_PERMISSIONS_CLASS);
 }
 
-function webViewerPageRendered({ pageNumber, timestamp, error }) {
+function webViewerPageRendered({ pageNumber, error }) {
   // If the page is still visible when it has finished rendering,
   // ensure that the page number input loading indicator is hidden.
   if (pageNumber === PDFViewerApplication.page) {
@@ -2341,10 +2346,6 @@ function webViewerPageRendered({ pageNumber, timestamp, error }) {
     });
   }
 
-  PDFViewerApplication.externalServices.reportTelemetry({
-    type: "pageInfo",
-    timestamp,
-  });
   // It is a good time to report stream and font types.
   PDFViewerApplication.pdfDocument.getStats().then(function (stats) {
     PDFViewerApplication.externalServices.reportTelemetry({
diff --git a/web/base_viewer.js b/web/base_viewer.js
index 5f9f67747..9ae9952f8 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -554,7 +554,7 @@ class BaseViewer {
       if (evt.cssTransform || this._onePageRenderedCapability.settled) {
         return;
       }
-      this._onePageRenderedCapability.resolve();
+      this._onePageRenderedCapability.resolve({ timestamp: evt.timestamp });
 
       this.eventBus._off("pagerendered", this._onAfterDraw);
       this._onAfterDraw = null;