From c6fcdf474b7b4e0f7d130e092061782a6b90e018 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Wed, 10 Jul 2019 13:24:21 +0200
Subject: [PATCH] Remove the `intentState.receivingOperatorList` boolean since
 it's redundant

The `receivingOperatorList` property is currently tracked *twice* in the rendering code, both directly and inversely through the `intentState.operatorList.lastChunk` boolean. This type of double bookkeeping is never a good idea, since it's just too easy for the properties to accidentally fall out of sync.

In this case there's even a `cleanup`-related bug caused by this, which means that `PDFPageProxy._tryCleanup` will never be able to discard any data if there's an error on the worker-thread (as handled through the 'PageError' message).

Hence the simplest solution seems, at least to me, to update `PDFPageProxy._tryCleanup` to replace the `intentState.receivingOperatorList` check with a `!intentState.operatorList.lastChunk` check and completely remove the former property.
---
 src/display/api.js | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/display/api.js b/src/display/api.js
index 0fc1b155a..40efb5db0 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1023,7 +1023,6 @@ class PDFPageProxy {
     // If there's no displayReadyCapability yet, then the operatorList
     // was never requested before. Make the request and create the promise.
     if (!intentState.displayReadyCapability) {
-      intentState.receivingOperatorList = true;
       intentState.displayReadyCapability = createPromiseCapability();
       intentState.operatorList = {
         fnArray: [],
@@ -1125,7 +1124,6 @@ class PDFPageProxy {
     if (!intentState.opListReadCapability) {
       opListTask = {};
       opListTask.operatorListChanged = operatorListChanged;
-      intentState.receivingOperatorList = true;
       intentState.opListReadCapability = createPromiseCapability();
       intentState.renderTasks = [];
       intentState.renderTasks.push(opListTask);
@@ -1241,7 +1239,7 @@ class PDFPageProxy {
         Object.keys(this.intentStates).some(function(intent) {
           const intentState = this.intentStates[intent];
           return (intentState.renderTasks.length !== 0 ||
-                  intentState.receivingOperatorList);
+                  !intentState.operatorList.lastChunk);
         }, this)) {
       return;
     }
@@ -1290,7 +1288,6 @@ class PDFPageProxy {
     }
 
     if (operatorListChunk.lastChunk) {
-      intentState.receivingOperatorList = false;
       this._tryCleanup();
     }
   }