Currently we repeat the `FeatureTest.isOffscreenCanvasSupported` checks all over the worker-thread code, and with upcoming changes this will become even "worse".
Hence this patch, which changes the *worker-thread* default value for the `isOffscreenCanvasSupported`-parameter to `false` and moves the feature-testing into the `BasePdfManager`-constructor.
*Please note:* This patch is written using the GitHub UI, since I'm currently without a dev machine, so hopefully it works correctly.
Currently these classes take a bunch of parameters (somewhat randomly ordered), probably because this is very old code that's been extended over the years.
Hence this patch changes the constructors to use parameter-objects instead, which improves consistency and (slightly) reduces the amount of code as well.
*Please note:* Also removes the `msgHandler`-property on these classes, since I cannot find a single call-site that accesses it.
After the clean-up in PR 15616, the `PdfManager.onLoadedStream` method now only has a single call-site.
Hence why this patch suggests that we remove this method and replace it with an *optional* parameter in `PdfManager.requestLoadedStream` instead. By making the new behaviour opt-in, we'll thus not change any existing call-site.
*This is very old code, and it could thus do with some simplification.*
Note how in the `src/core/worker.js` file we're combining both the `PdfManager.requestLoadedStream` and `PdfManager.onLoadedStream` methods in order to access the stream-data. This seems unnecessary, and it's simple enough to always let the `PdfManager.requestLoadedStream` method return the stream-data as well.
*Please note:* These changes will primarily benefit longer documents, somewhat at the expense of e.g. one-page documents.
The existing `PDFDocumentProxy.getStats` function, which in the default viewer is called for each rendered page, requires a round-trip to the worker-thread in order to obtain the current document stats. In the default viewer, we currently make one such API-call for *every rendered* page.
This patch proposes replacing that method with a *synchronous* `PDFDocumentProxy.stats` getter instead, combined with re-factoring the worker-thread code by adding a `DocStats`-class to track Stream/Font-types and *only send* them to the main-thread *the first time* that a type is encountered.
Note that in practice most PDF documents only use a fairly limited number of Stream/Font-types, which means that in longer documents most of the `PDFDocumentProxy.getStats`-calls will return the same data.[1]
This re-factoring will obviously benefit longer document the most[2], and could actually be seen as a regression for one-page documents, since in practice there'll usually be a couple of "DocStats" messages sent during the parsing of the first page. However, if the user zooms/rotates the document (which causes re-rendering), note that even a one-page document would start to benefit from these changes.
Another benefit of having the data available/cached in the API is that unless the document stats change during parsing, repeated `PDFDocumentProxy.stats`-calls will return *the same identical* object.
This is something that we can easily take advantage of in the default viewer, by now *only* reporting "documentStats" telemetry[3] when the data actually have changed rather than once per rendered page (again beneficial in longer documents).
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[1] Furthermore, the maximium number of `StreamType`/`FontType` are `10` respectively `12`, which means that regardless of the complexity and page count in a PDF document there'll never be more than twenty-two "DocStats" messages sent; see 41ac3f0c07/src/shared/util.js (L206-L232)
[2] One example is the `pdf.pdf` document in the test-suite, where rendering all of its 1310 pages only result in a total of seven "DocStats" messages being sent from the worker-thread.
[3] Reporting telemetry, in Firefox, includes using `JSON.stringify` on the data and then sending an event to the `PdfStreamConverter.jsm`-code.
In that code the event is handled and `JSON.parse` is used to retrieve the data, and in the "documentStats"-case we'll then iterate through the data to avoid double-reporting telemetry; see https://searchfox.org/mozilla-central/rev/8f4c180b87e52f3345ef8a3432d6e54bd1eb18dc/toolkit/components/pdfjs/content/PdfStreamConverter.jsm#515-549
- when binding (after parsing) we get a map between some template nodes and some data nodes;
- so set user data in input handlers in using data node uids in the annotation storage;
- to save the form, just put the value we have in the storage in the correct data nodes, serialize the xml as a string and then write the string at the end of the pdf using src/core/writer.js;
- fix few bugs around data bindings:
- the "Off" issue in Bug 1716980.
- Different fonts can be used in xfa and some of them are embedded in the pdf.
- Load all the fonts in window.document.
Update src/core/document.js
Co-authored-by: Jonas Jenwald <jonas.jenwald@gmail.com>
Update src/core/worker.js
Co-authored-by: Jonas Jenwald <jonas.jenwald@gmail.com>
- add an option to enable XFA rendering if any;
- for now, let the canvas layer: it could be useful to implement XFAF forms (embedded pdf in xml stream for the background and xfa form for the foreground);
- ui elements in template DOM are pretty close to their html counterpart so we generate a fake html DOM from template one:
- it makes easier to translate template properties to html ones;
- it makes faster the creation of the html element in the main thread.
While there is nothing *outright* wrong with the existing implementation, it can however lead to increased memory usage in one particular case (that I completely overlooked when implementing this):
For "data:"-URLs, which by definition contains the entire PDF document and can thus be arbitrarily large, we obviously want to avoid sending, storing, and/or logging the "raw" docBaseUrl in that case.
To address this, this patch makes the following changes:
- Ignore any non-string in the `docBaseUrl` option passed to `getDocument`, since those are unsupported anyway, already on the main-thread.
- Ignore "data:"-URLs in the `docBaseUrl` option passed to `getDocument`, to avoid having to send what could potentially be a *very* long string to the worker-thread.
- Parse the `docBaseUrl` option *directly* in the `BasePdfManager`-constructors, on the worker-thread, to avoid having to store the "raw" docBaseUrl in the first place.
When "Cleanup" is triggered, you obviously need to remove all globally cached data on *both* the main- and worker-threads.
However, the current the implementation of the `GlobalImageCache.clear` method also means that we lose *all* information about which images were cached and not just their data. This thus has the somewhat unfortunate side-effect of requiring images, which were previously known to be "global", to *again* having to reach `NUM_PAGES_THRESHOLD` before being cached again.
To avoid doing unnecessary parsing after "Cleanup", we can thus let `GlobalImageCache.clear` keep track of which images were cached while still removing their actual data. This should not have any significant impact on memory usage, since the only extra thing being kept is a `RefSetCache` (essentially an Object) with a couple of `Set`s containing only integers.
In order to eventually get rid of SystemJS and start using native `import`s instead, we'll need to provide "complete" file identifiers since otherwise there'll be MIME type errors when attempting to use `import`.
Note that Prettier, purposely, has only limited [configuration options](https://prettier.io/docs/en/options.html). The configuration file is based on [the one in `mozilla central`](https://searchfox.org/mozilla-central/source/.prettierrc) with just a few additions (to avoid future breakage if the defaults ever changes).
Prettier is being used for a couple of reasons:
- To be consistent with `mozilla-central`, where Prettier is already in use across the tree.
- To ensure a *consistent* coding style everywhere, which is automatically enforced during linting (since Prettier is used as an ESLint plugin). This thus ends "all" formatting disussions once and for all, removing the need for review comments on most stylistic matters.
Many ESLint options are now redundant, and I've tried my best to remove all the now unnecessary options (but I may have missed some).
Note also that since Prettier considers the `printWidth` option as a guide, rather than a hard rule, this patch resorts to a small hack in the ESLint config to ensure that *comments* won't become too long.
*Please note:* This patch is generated automatically, by appending the `--fix` argument to the ESLint call used in the `gulp lint` task. It will thus require some additional clean-up, which will be done in a *separate* commit.
(On a more personal note, I'll readily admit that some of the changes Prettier makes are *extremely* ugly. However, in the name of consistency we'll probably have to live with that.)
There's a number of spots in the current code, and tests, where `cancel` methods are not called with appropriate arguments (leading to Promises not being rejected with Errors as intended).
In some cases the cancel `reason` is implicitly set to `undefined`, and in others the cancel `reason` is just a plain String. To address this inconsistency, the patch changes things such that cancelling is done with `AbortException`s everywhere instead.
The `src/shared/util.js` file is being bundled into both the `pdf.js` and `pdf.worker.js` files, meaning that its code is by definition duplicated.
Some main-thread only utility functions have already been moved to a separate `src/display/display_utils.js` file, and this patch simply extends that concept to utility functions which are used *only* on the worker-thread.
Note in particular the `getInheritableProperty` function, which expects a `Dict` as input and thus *cannot* possibly ever be used on the main-thread.
After PR 9340 all glyphs are now re-mapped to a Private Use Area (PUA) which means that if a font fails to load, for whatever reason[1], all glyphs in the font will now render as Unicode glyph outlines.
This obviously doesn't look good, to say the least, and might be seen as a "regression" since previously many glyphs were left in their original positions which provided a slightly better fallback[2].
Hence this patch, which implements a *general* fallback to the PDF.js built-in font renderer for fonts that fail to load (i.e. are rejected by the sanitizer). One caveat here is that this only works for the Font Loading API, since it's easy to handle errors in that case[3].
The solution implemented in this patch does *not* in any way delay the loading of valid fonts, which was the problem with my previous attempt at a solution, and will only require a bit of extra work/waiting for those fonts that actually fail to load.
*Please note:* This patch doesn't fix any of the underlying PDF.js font conversion bugs that's responsible for creating corrupt font files, however it does *improve* rendering in a number of cases; refer to this possibly incomplete list:
[Bug 1524888](https://bugzilla.mozilla.org/show_bug.cgi?id=1524888)
Issue 10175
Issue 10232
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[1] Usually because the PDF.js font conversion code wasn't able to parse the font file correctly.
[2] Glyphs fell back to some default font, which while not accurate was more useful than the current state.
[3] Furthermore I'm not sure how to implement this generally, assuming that's even possible, and don't really have time/interest to look into it either.
For proof-of-concept, this patch converts a couple of `Promise` returning methods to use `async` instead.
Please note that the `generic` build, based on this patch, has been successfully testing in IE11 (i.e. the viewer loads and nothing is obviously broken).
Being able to use modern JavaScript features like `async`/`await` is a huge plus, but there's one (obvious) side-effect: The size of the built files will increase slightly (unless `SKIP_BABEL == true`). That's unavoidable, but seems like a small price to pay in the grand scheme of things.
Finally, note that the `chromium` build target was changed to no longer skip Babel translation, since the Chrome extension still supports version `49` of the browser (where native `async` support isn't available).
Please note that the `glyphlist.js` and `unicode.js` files are converted to CommonJS modules instead, since Babel cannot handle files that large and they are thus excluded from transpilation.
Please see http://eslint.org/docs/rules/object-shorthand.
For the most part, these changes are of the search-and-replace kind, and the previously enabled `no-undef` rule should complement the tests in helping ensure that no stupid errors crept into to the patch.
We're already passing in a, currently unused, `PdfManager` instance when initializing the `XRef`. To avoid having to pass a single `password` parameter around, we could thus simply get the `password` through the `PdfManager` instance instead.
This patch also removes the `UpdatePassword` message, in favour of using the `sendWithPromise` method of `MessageHandler`.
Furthermore, the patch also refactors the `BasePdfManager_updatePassword`/`BasePdfManager_passwordChanged` methods (in pdf_manager.js), and the `pdfManagerReady` function (in worker.js).
Note that in `FIREFOX/MOZCENTRAL/CHROME` builds of the standard viewer the `docBaseUrl` parameter will be set by default, since in that case it makes sense to use the current URL as a base.
For the `GENERIC` viewer, or the API itself, it doesn't make sense to try and set the `docBaseUrl` by default. However, custom deployments/implementations may still find the parameter useful.
