From 80441346a3fe91b52a08331ff278da6a43cf0971 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 1 Feb 2018 16:43:10 +0100
Subject: [PATCH] Fallback to the built-in JPEG decoder if 'JpegStream', in
`src/display/api.js`, fails to load the image
This works by making `PartialEvaluator.buildPaintImageXObject` wait for the success/failure of `loadJpegStream` on the API side *before* parsing continues.
Please note that in practice, it should be quite rare for the browser to fail loading/decoding of a JPEG image. In the general case, it should thus not be completely surprising if even `src/core/jpg.js` will fail to decode the image.
---
src/core/evaluator.js | 52 +++++++++++++++++++++++++++++++------------
src/display/api.js | 10 ++++-----
2 files changed, 43 insertions(+), 19 deletions(-)
diff --git a/src/core/evaluator.js b/src/core/evaluator.js
index 2ad04dbca..302ed26a5 100644
--- a/src/core/evaluator.js
+++ b/src/core/evaluator.js
@@ -349,7 +349,8 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
},
buildPaintImageXObject({ resources, image, isInline = false, operatorList,
- cacheKey, imageCache, }) {
+ cacheKey, imageCache,
+ forceDisableNativeImageDecoder = false, }) {
var dict = image.dict;
var w = dict.get('Width', 'W');
var h = dict.get('Height', 'H');
@@ -419,28 +420,47 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
return Promise.resolve();
}
- var nativeImageDecoderSupport = this.options.nativeImageDecoderSupport;
+ const nativeImageDecoderSupport = forceDisableNativeImageDecoder ?
+ NativeImageDecoding.NONE : this.options.nativeImageDecoderSupport;
// If there is no imageMask, create the PDFImage and a lot
// of image processing can be done here.
var objId = 'img_' + this.idFactory.createObjId();
- operatorList.addDependency(objId);
- args = [objId, w, h];
if (nativeImageDecoderSupport !== NativeImageDecoding.NONE &&
!softMask && !mask && image instanceof JpegStream &&
NativeImageDecoder.isSupported(image, this.xref, resources,
this.pdfFunctionFactory)) {
// These JPEGs don't need any more processing so we can just send it.
- operatorList.addOp(OPS.paintJpegXObject, args);
- this.handler.send('obj', [objId, this.pageIndex, 'JpegStream',
- image.getIR(this.options.forceDataSchema)]);
- if (cacheKey) {
- imageCache[cacheKey] = {
- fn: OPS.paintJpegXObject,
- args,
- };
- }
- return Promise.resolve();
+ return this.handler.sendWithPromise('obj', [
+ objId, this.pageIndex, 'JpegStream',
+ image.getIR(this.options.forceDataSchema)
+ ]).then(function() {
+ // Only add the dependency once we know that the native JPEG decoding
+ // succeeded, to ensure that rendering will always complete.
+ operatorList.addDependency(objId);
+ args = [objId, w, h];
+
+ operatorList.addOp(OPS.paintJpegXObject, args);
+ if (cacheKey) {
+ imageCache[cacheKey] = {
+ fn: OPS.paintJpegXObject,
+ args,
+ };
+ }
+ }, (reason) => {
+ warn('Native JPEG decoding failed -- trying to recover: ' +
+ (reason && reason.message));
+ // Try to decode the JPEG image with the built-in decoder instead.
+ return this.buildPaintImageXObject({
+ resources,
+ image,
+ isInline,
+ operatorList,
+ cacheKey,
+ imageCache,
+ forceDisableNativeImageDecoder: true,
+ });
+ });
}
// Creates native image decoder only if a JPEG image or mask is present.
@@ -457,6 +477,10 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
});
}
+ // Ensure that the dependency is added before the image is decoded.
+ operatorList.addDependency(objId);
+ args = [objId, w, h];
+
PDFImage.buildImage({
handler: this.handler,
xref: this.xref,
diff --git a/src/display/api.js b/src/display/api.js
index d50651c42..0819b9736 100644
--- a/src/display/api.js
+++ b/src/display/api.js
@@ -1817,22 +1817,22 @@ var WorkerTransport = (function WorkerTransportClosure() {
switch (type) {
case 'JpegStream':
imageData = data[3];
- new Promise((resolve, reject) => {
+ return new Promise((resolve, reject) => {
const img = new Image();
img.onload = function() {
resolve(img);
};
img.onerror = function() {
reject(new Error('Error during JPEG image loading'));
+ // Note that when the browser image loading/decoding fails,
+ // we'll fallback to the built-in PDF.js JPEG decoder; see
+ // `PartialEvaluator.buildPaintImageXObject` in the
+ // `src/core/evaluator.js` file.
};
img.src = imageData;
}).then((img) => {
pageProxy.objs.resolve(id, img);
- }, (reason) => {
- warn(reason);
- pageProxy.objs.resolve(id, null);
});
- break;
case 'Image':
imageData = data[3];
pageProxy.objs.resolve(id, imageData);