From 1362cd91d0f9816825e5f179eed174e92c4f2ccd Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 12 Jan 2023 14:43:56 +0100
Subject: [PATCH] Improve input validation in
 `PDFDataTransportStream._onReceiveData` (PR 15908 follow-up)

The mozilla-central [method `PdfDataListener.readData`](https://searchfox.org/mozilla-central/rev/893a8f062ec6144c84403fbfb0a57234418b89cf/toolkit/components/pdfjs/content/PdfStreamConverter.jsm#207-210) can return `null`, hence it seems like a very good idea to update `PDFDataTransportStream._onReceiveData` to handle that gracefully since the current code will throw in that case.

Also, improves the JSDocs for the `PDFDataRangeTransport` class in the API.
---
 src/display/api.js              | 29 ++++++++++++++++++++++++++++-
 src/display/transport_stream.js |  7 ++++---
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/src/display/api.js b/src/display/api.js
index 86564b63e..c999d1550 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -665,7 +665,7 @@ class PDFDocumentLoadingTask {
 class PDFDataRangeTransport {
   /**
    * @param {number} length
-   * @param {Uint8Array} initialData
+   * @param {Uint8Array|null} initialData
    * @param {boolean} [progressiveDone]
    * @param {string} [contentDispositionFilename]
    */
@@ -687,28 +687,48 @@ class PDFDataRangeTransport {
     this._readyCapability = createPromiseCapability();
   }
 
+  /**
+   * @param {function} listener
+   */
   addRangeListener(listener) {
     this._rangeListeners.push(listener);
   }
 
+  /**
+   * @param {function} listener
+   */
   addProgressListener(listener) {
     this._progressListeners.push(listener);
   }
 
+  /**
+   * @param {function} listener
+   */
   addProgressiveReadListener(listener) {
     this._progressiveReadListeners.push(listener);
   }
 
+  /**
+   * @param {function} listener
+   */
   addProgressiveDoneListener(listener) {
     this._progressiveDoneListeners.push(listener);
   }
 
+  /**
+   * @param {number} begin
+   * @param {Uint8Array|null} chunk
+   */
   onDataRange(begin, chunk) {
     for (const listener of this._rangeListeners) {
       listener(begin, chunk);
     }
   }
 
+  /**
+   * @param {number} loaded
+   * @param {number|undefined} total
+   */
   onDataProgress(loaded, total) {
     this._readyCapability.promise.then(() => {
       for (const listener of this._progressListeners) {
@@ -717,6 +737,9 @@ class PDFDataRangeTransport {
     });
   }
 
+  /**
+   * @param {Uint8Array|null} chunk
+   */
   onDataProgressiveRead(chunk) {
     this._readyCapability.promise.then(() => {
       for (const listener of this._progressiveReadListeners) {
@@ -737,6 +760,10 @@ class PDFDataRangeTransport {
     this._readyCapability.resolve();
   }
 
+  /**
+   * @param {number} begin
+   * @param {number} end
+   */
   requestDataRange(begin, end) {
     unreachable("Abstract method PDFDataRangeTransport.requestDataRange");
   }
diff --git a/src/display/transport_stream.js b/src/display/transport_stream.js
index 874cb5805..38460d55d 100644
--- a/src/display/transport_stream.js
+++ b/src/display/transport_stream.js
@@ -77,9 +77,10 @@ class PDFDataTransportStream {
   }
 
   _onReceiveData({ begin, chunk }) {
-    const buffer = this.#transferPdfData
-      ? chunk.buffer
-      : new Uint8Array(chunk).buffer;
+    const buffer =
+      this.#transferPdfData && chunk?.length >= 0
+        ? chunk.buffer
+        : new Uint8Array(chunk).buffer;
 
     if (begin === undefined) {
       if (this._fullRequestReader) {