Merge pull request #13796 from Snuffleupagus/issue-13794

Allow `StreamsSequenceStream.readBlock` to skip sub-streams with errors (issue 13794)

src/core/decode_stream.js

@@ -127,7 +127,7 @@ class DecodeStream extends BaseStream {
 }
 
 class StreamsSequenceStream extends DecodeStream {
-  constructor(streams) {
+  constructor(streams, onError = null) {
     let maybeLength = 0;
     for (const stream of streams) {
       maybeLength +=
@@ -138,6 +138,7 @@ class StreamsSequenceStream extends DecodeStream {
     super(maybeLength);
 
     this.streams = streams;
+    this._onError = onError;
   }
 
   readBlock() {
@@ -147,7 +148,16 @@ class StreamsSequenceStream extends DecodeStream {
       return;
     }
     const stream = streams.shift();
-    const chunk = stream.getBytes();
+    let chunk;
+    try {
+      chunk = stream.getBytes();
+    } catch (reason) {
+      if (this._onError) {
+        this._onError(reason, stream.dict && stream.dict.objId);
+        return;
+      }
+      throw reason;
+    }
     const bufferLength = this.bufferLength;
     const newLength = bufferLength + chunk.length;
     const buffer = this.ensureBuffer(newLength);

src/core/document.js

@@ -30,6 +30,7 @@ import {
   stringToPDFString,
   stringToUTF8String,
   unreachable,
+  UNSUPPORTED_FEATURES,
   Util,
   warn,
 } from "../shared/util.js";
@@ -225,16 +226,35 @@ class Page {
     return shadow(this, "rotate", rotate);
   }
 
+  /**
+   * @private
+   */
+  _onSubStreamError(handler, reason, objId) {
+    if (this.evaluatorOptions.ignoreErrors) {
+      // Error(s) when reading one of the /Contents sub-streams -- sending
+      // unsupported feature notification and allow parsing to continue.
+      handler.send("UnsupportedFeature", {
+        featureId: UNSUPPORTED_FEATURES.errorContentSubStream,
+      });
+      warn(`getContentStream - ignoring sub-stream (${objId}): "${reason}".`);
+      return;
+    }
+    throw reason;
+  }
+
   /**
    * @returns {Promise<BaseStream>}
    */
-  getContentStream() {
+  getContentStream(handler) {
     return this.pdfManager.ensure(this, "content").then(content => {
       if (content instanceof BaseStream) {
         return content;
       }
       if (Array.isArray(content)) {
-        return new StreamsSequenceStream(content);
+        return new StreamsSequenceStream(
+          content,
+          this._onSubStreamError.bind(this, handler)
+        );
       }
       // Replace non-existent page content with empty content.
       return new NullStream();
@@ -307,7 +327,7 @@ class Page {
     renderInteractiveForms,
     annotationStorage,
   }) {
-    const contentStreamPromise = this.getContentStream();
+    const contentStreamPromise = this.getContentStream(handler);
     const resourcesPromise = this.loadResources([
       "ColorSpace",
       "ExtGState",
@@ -417,7 +437,7 @@ class Page {
     sink,
     combineTextItems,
   }) {
-    const contentStreamPromise = this.getContentStream();
+    const contentStreamPromise = this.getContentStream(handler);
     const resourcesPromise = this.loadResources([
       "ExtGState",
       "Font",

src/shared/util.js

@@ -335,6 +335,7 @@ const UNSUPPORTED_FEATURES = {
   errorFontBuildPath: "errorFontBuildPath",
   errorFontGetPath: "errorFontGetPath",
   errorMarkedContent: "errorMarkedContent",
+  errorContentSubStream: "errorContentSubStream",
 };
 
 const PasswordResponses = {

test/pdfs/issue13794.pdf.link

@@ -0,0 +1 @@
+https://github.com/mozilla/pdf.js/files/6876708/Scan-to-Mail-PDF1_.1.pdf

test/test_manifest.json

@@ -1399,6 +1399,14 @@
        "lastPage": 7,
        "type": "eq"
     },
+    {  "id": "issue13794",
+       "file": "pdfs/issue13794.pdf",
+       "md5": "6b4c099e04c9df145198740f2bf75c48",
+       "link": true,
+       "rounds": 1,
+       "firstPage": 3,
+       "type": "eq"
+    },
     {  "id": "issue9262",
        "file": "pdfs/issue9262_reduced.pdf",
        "md5": "5347ce2d7b3866625c22e115fd90e0de",