From d9743e462dd27d3f01674449e5ccec0eab2afd59 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 29 Nov 2018 11:31:49 +0100
Subject: [PATCH] Replace the `OVERRIDES` list in
 `PDFViewerApplication._readPreferences` with a `disablePreferences`, in
 `GENERIC` builds, `AppOption instead

Rather than having a (somewhat) randomly choosen list of Preferences which `AppOptions` are allowed to override, it makes much more sense to simply add an AppOption to allow custom implementations to ignore Preferences altogether (it's also inline with the AppOption that allows the `ViewHistory` to be bypassed on load).
---
 web/app.js         | 19 ++++++-------------
 web/app_options.js |  8 ++++++++
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/web/app.js b/web/app.js
index e9ba568b6..5358e5810 100644
--- a/web/app.js
+++ b/web/app.js
@@ -169,21 +169,14 @@ let PDFViewerApplication = {
    * @private
    */
   async _readPreferences() {
-    // A subset of the Preferences that `AppOptions`, for compatibility reasons,
-    // is allowed to override if the `AppOptions` values matches the ones below.
-    const OVERRIDES = {
-      disableFontFace: true,
-      disableRange: true,
-      disableStream: true,
-      textLayerMode: TextLayerMode.DISABLE,
-    };
-
+    if (AppOptions.get('disablePreferences') === true) {
+      // Give custom implementations of the default viewer a simpler way to
+      // opt-out of having the `Preferences` override existing `AppOptions`.
+      return;
+    }
     try {
       const prefs = await this.preferences.getAll();
-      for (let name in prefs) {
-        if ((name in OVERRIDES) && AppOptions.get(name) === OVERRIDES[name]) {
-          continue;
-        }
+      for (const name in prefs) {
         AppOptions.set(name, prefs[name]);
       }
     } catch (reason) { }
diff --git a/web/app_options.js b/web/app_options.js
index 08fb28848..220b28455 100644
--- a/web/app_options.js
+++ b/web/app_options.js
@@ -58,6 +58,9 @@ const defaultOptions = {
     value: false,
     kind: OptionKind.VIEWER,
   },
+  /**
+   * The `disablePreferences` is, conditionally, defined below.
+   */
   enablePrintAutoRotate: {
     /** @type {boolean} */
     value: false,
@@ -218,6 +221,11 @@ const defaultOptions = {
 };
 if (typeof PDFJSDev === 'undefined' ||
     PDFJSDev.test('!PRODUCTION || GENERIC')) {
+  defaultOptions.disablePreferences = {
+    /** @type {boolean} */
+    value: false,
+    kind: OptionKind.VIEWER,
+  };
   defaultOptions.locale = {
     /** @type {string} */
     value: (typeof navigator !== 'undefined' ? navigator.language : 'en-US'),