- Use optional chaining when clearing various data-structures, since that's slightly shorter.
- Ensure that checking for the existence of `#_hcmCache`-data won't cause it to be initialized. (Note how `this.#hcmCache` is actually a getter.)
- Actually reset the `#_hcmCache`-data when that's appropriate, e.g. when closing the PDF document.
- Ensure that `pdfjsTestingUtils` is available when running benchmarking, since that shouldn't be done in TESTING-mode.
- Exclude the `test/stats/results/` folder from linting, since it'll contain *generated* JSON-files.
When iterating through `useCMap` the value is already available, without having to manually invoke the `lookup`-method.
While this will likely not affect performance in any noticeable way, it's nonetheless unnecessary to lookup an already available value twice.
This was previously attempted in PR 13371, but had to be reverted because of issues related to SystemJS (which has since been removed).
Also, while unrelated, shortens an existing conditional assignment.
The purpose of these changes is to make it more difficult to accidentally include logging statements, used during development and debugging, when submitting patches for review.
For (almost) all code residing in the `src/` folder we should use our existing helper functions to ensure that all logging can be controlled via the `verbosity` API-option.
For the `test/unit/` respectively `test/integration/` folders we shouldn't need any "normal" logging, but it should be OK to print the *occasional* warning/error message.
Please find additional details about the ESLint rule at https://eslint.org/docs/latest/rules/no-console
Given that there are multiple issues with `ImageDecoder` in Chromium browsers, affecting both BMP and JPEG images, for now we (by default) disable that functionality there to avoid problems.
This also means that we can remove the previously added, and separate, `isChrome` API-option.
This allows end-users to forcibly disable `ImageDecoder` usage, even if the browser appears to support it (similar to the pre-existing option for `OffscreenCanvas`).
Flat config is the new config system used by ESLint 9.
To make the migration easier, they also added
flat config support to ESLint 8.
This commit migrates the various ESLint configs in the repository to use
the new system, **without** upgrading to ESLint 9 yet.
Given that `ImageData` has been supported for many years in all browsers, see [MDN](https://developer.mozilla.org/en-US/docs/Web/API/ImageData#browser_compatibility), we have a `typeof` check that's only necessary in Node.js environments.
Since the `@napi-rs/canvas` package provides that functionality, we can thus add an `ImageData` polyfill which allows us to ever so slightly simplify the code.
The `@napi-rs/canvas` package has fewer dependencies, which should *hopefully* make installing and using it easier for `pdfjs-dist` end-users. (Over the years we've seen, repeatedly, that `canvas` can be difficult to install successfully.)
Furthermore, this package includes more functionality (such as `Path2D`) which reduces the overall number of dependencies in the PDF.js project.
One point to note is that `@napi-rs/canvas` is a fair bit newer than `canvas`, and has a lot fewer users, however looking at the commit history it does seem to be actively maintained.
Note that I've successfully tested the [Node.js examples](https://github.com/mozilla/pdf.js/tree/master/examples/node), in particular the `pdf2png` one, with this patch applied and things appear to work fine.
Please see:
- https://www.npmjs.com/package/@napi-rs/canvas
- https://github.com/Brooooooklyn/canvas
Fixes https://github.com/mozilla/pdf.js/issues/18957https://github.com/mozilla/pdf.js/pull/18682 introduced a regression that causes the following error:
```
Uncaught TypeError: Failed to construct 'Headers': Invalid name
at PDFNetworkStreamFullRequestReader._onHeadersReceived (pdf.mjs:10214:29)
at NetworkManager.onStateChange (pdf.mjs:10103:22)
```
The mentioned PR replaced a call to `getResponseHeader()` with `getAllResponseHeaders()` without handling cases where it may return null or an empty string. Quote from the [docs](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/getAllResponseHeaders#return_value):
> Returns:
>
>A string representing all of the response's headers (except those whose field name is Set-Cookie) separated by CRLF, or null if no response has been received. If a network error happened, an empty string is returned.
Run the following code and observe the error in the console. Note that the URL is intentionally set to an invalid value to simulate network error
```js
<script src="//mozilla.github.io/pdf.js/build/pdf.mjs" type="module"></script>
<script type="module">
var url = 'blob:';
pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.mjs';
var loadingTask = pdfjsLib.getDocument(url);
loadingTask.promise
.then((pdf) => console.log('PDF loaded'))
.catch((reason) => console.error(reason));
</script>
```
The problem with the referenced PDF document has nothing to do with invalid dates, as the issue seems to suggest, but rather with the fact that it has neither an XRef table nor a trailer dictionary.
Given that crucial parts of the internal document structure is missing, you might argue that it's not really a PDF document.
In an attempt to support this kind of corruption, we'll simply iterate through all (previously found) XRef entries and pick one that *might* be a valid /Root dictionary.
There's obviously no guarantee that this works, and it might not be fast in larger PDF documents, but at least it cannot be any worse than *immediately* throwing `InvalidPDFException` as we previously did here.
*Please note:* I'm totally fine with this patch being rejected, since it's somewhat questionable if we should actually attempt to support "PDF documents" with this level of corruption.
- This helper function has only a single call-site, and the function is fairly short.
- It'll only be invoked if range requests are *disabled*, or if the entire PDF manages to load *before* the headers are resolved (which is very unlikely).
Hence, by default, this helper function is not invoked.
- By inlining the code we're able to utilize the existing error-handling at the call-site, rather than having to duplicate it, which further reduces the size of this code.
Finally, while slightly unrelated, this patch also adds optional chaining in one spot in the file (PR 16424 follow-up).
I discovered that doing skip-cache re-reloading of https://opensource.adobe.com/dc-acrobat-sdk-docs/pdfstandards/PDF32000_2008.pdf would *intermittently* cause (some of) the AnnotationLayers to break with errors printed in the console (see below).
In hindsight this bug is really obvious, however it took me quite some time to find it, since the `StructTreePage.prototype.serializable` getter will lookup various data and all of those cases can fail during loading when streaming and/or range requests are being used.
Finally, to prevent any future errors, ensure that the viewer won't break in these sort of situations.
```
Uncaught (in promise)
Object { message: "Missing data [19098296, 19098297)", name: "UnknownErrorException", details: "MissingDataException: Missing data [19098296, 19098297)", stack: "BaseExceptionClosure@resource://pdf.js/build/pdf.mjs:453:29\n@resource://pdf.js/build/pdf.mjs:456:2\n" }
viewer.mjs:8801:55
\#renderAnnotationLayer: "UnknownErrorException: Missing data [17552729, 17552730)". viewer.mjs:8737:15
Uncaught (in promise)
Object { message: "Missing data [17552729, 17552730)", name: "UnknownErrorException", details: "MissingDataException: Missing data [17552729, 17552730)", stack: "BaseExceptionClosure@resource://pdf.js/build/pdf.mjs:453:29\n@resource://pdf.js/build/pdf.mjs:456:2\n" }
viewer.mjs:8801:55
```
- Over time the number and size of these factories have increased, especially the `DOMFilterFactory` class, and this split should thus aid readability/maintainability of the code.
- By introducing a couple of new import maps we can avoid bundling the `DOMCMapReaderFactory`/`DOMStandardFontDataFactory` classes in the Firefox PDF Viewer, since they are dead code there given that worker-thread fetching is always being used.
- This patch has been successfully tested, by running `$ ./mach test toolkit/components/pdfjs/`, in a local Firefox artifact-build.
*Note:* This patch reduces the size of the `gulp mozcentral` output by `1.3` kilo-bytes, which isn't a lot but still cannot hurt.
This way we can directly throw Errors, rather than having to "manually" return rejected Promises, which is ever so slightly shorter.
Also, since `useWorkerFetch` is always true in MOZCENTRAL builds these message-handlers should not be invoked there.
