With the current implementation of `PDFDocument.hasJSActions`, in the worker-thread, we're not actually handling not-yet-loaded data correctly. This can thus fail in *two* different ways:
- The `PDFDocument.fieldObjects` getter (and its helper method), while it may *return* a Promise, still fetches all of its data synchronously and it can thus throw a `MissingDataException` during parsing.
- The `Catalog.jsActions` getter, which is completely synchronous, can obviously throw a `MissingDataException` during parsing.
If either of these cases occur currently, the `PDFDocumentProxy.hasJSActions` method in the API can either return a *rejected* Promise (which it never should) or possibly "hang" and never resolve.
*Please note:* While I've not *yet* seen this error in an actual PDF document, it can happen during loading if you're unlucky enough with e.g. the structure of the PDF document and/or the download speed offered by the server.
This patch is thus based on code-inspection *and* on manually throwing a `MissingDataException` on the first access of `Catalog.jsActions` to simulate this situation.
Finally, this patch adds a couple of *API* unit-tests for this (since none existed).
This is first of all consistent with existing API-methods, where we return `null` when the data in question doesn't exist. Secondly, it should also be (slightly) more efficient since there's less dummy-data that we need to transfer between threads.
Finally, this prevents us from adding an empty/unnecessary span to *every* single page even in documents without any structure tree data.
The done callbacks are an outdated mechanism to signal Jasmine that a
unit test is done, mostly in cases where a unit test needed to wait for
an asynchronous operation to complete before doing its assertions.
Nowadays a much better mechanism is in place for that, namely simply
passing an asynchronous function to Jasmine, so we don't need callbacks
anymore (which require more code and may be more difficult to reason
about).
In these particular cases though the done callbacks never had any real
use since nothing asynchronous happens in these places. Synchronous
functions don't need to use done callbacks since Jasmine simply knows
it's done when the function reaches its normal end, so we can safely get
rid of these callbacks. The telltale sign is if the done callback is
used unconditionally at the end of the function.
This is all done in an effort to over time get rid of all callbacks in
the unit test code.
- but don't validate them for now;
- Firefox will display a bar to warn that the signature validation is not supported (see https://bugzilla.mozilla.org/show_bug.cgi?id=854315)
- almost all (all ?) pdf readers display signatures;
- validation is done in edge but for now it's behind a pref.
When a PDF is "marked" we now generate a separate DOM that represents
the structure tree from the PDF. This DOM is inserted into the <canvas>
element and allows screen readers to walk the tree and have more
information about headings, images, links, etc. To link the structure
tree DOM (which is empty) to the text layer aria-owns is used. This
required modifying the text layer creation so that marked items are
now tracked.
Currently the `fontName`-property contains an actual /Name-instance, which is a problem given that its fallback value is an empty string; see ca7f546828/src/core/default_appearance.js (L35)
The reason that this is a problem can be seen in ca7f546828/src/core/primitives.js (L30-L34), since an empty string short-circuits the cache. Essentially, in PDF documents, a /Name-instance cannot be empty and the way that the `DefaultAppearanceEvaluator` does things is unfortunately not entirely correct.
Hence the `fontName`-property is changed to instead contain a string, rather than a /Name-instance, which simplifies the code overall.
*Please note:* I'm tagging this patch with "[api-minor]", since PR 12831 is included in the current pre-release (although we're not using the `fontName`-property in the display-layer).
Currently only URL-strings are officially supported by `getDocument`, however at this point in time I cannot really see any compelling reason to not support `URL`-objects as well.
Most likely the reason that we've don't already support `URL`-objects, in `getDocument`, is that historically `URL` wasn't fully implemented across browsers and our old polyfill wasn't perfect; see https://developer.mozilla.org/en-US/docs/Web/API/URL/URL#browser_compatibility
*Please note:* Because of how the `url` parameter is currently handled, there's actually *some* cases where passing a `URL`-object to `getDocument` already works. That, in my opinion, provides additional motivation for supporting `URL`-objects officially, since it makes the API more consistent.
The following is an attempt to summarize the *current* situation, based on the actual code rather than the JSDocs:
- `getDocument("url string")` works and is documented.[1]
- `getDocument({ url: "url string", })` works and is documented.[1]
- `getDocument(new URL(...))` throws immediately, since no supported parameters are found.
- `getDocument({ url: new URL(...), })` actually works even though it's not documented.[1] Originally, when data was fetched on the worker-thread, this would likely have thrown since `URL` isn't clonable.[2]
- `getDocument({ url: { abc: 123, }, })`, or some similarily meaningless input, will be "accepted" by `getDocument` and then throw a `MissingPDFException` when attempting to fetch the bogus data.
With the changes in this patch, not only is `URL`-objects now officially supported and documented when calling `getDocument`, but we'll also do a much better job at actually validating any URL-data passed to `getDocument` (and instead fail early).
---
[1] In *browsers*, we create a valid URL thus indirectly validating the input. In Node.js environments, on the other hand, no validation is done since obtaining a baseUrl is more difficult (and PDF.js is primarily written for browsers anyway).
[2] https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm#supported_types
- implement few positioning properties: position, width, height, anchor;
- implement font element;
- implement fill element (used by font) and its children (linear, radial, ...);
- font property is inherited from ancestor container (see https://www.pdfa.org/wp-content/uploads/2020/07/XFA-3_3.pdf#page=43) so let CSS handles that stuff;
- in order to reduce the number of properties to set, only set non default properties and put the default in CSS;
- set a background to some containers to be able to see them (will be removed in a future commit).
- 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.
It seems reasonable to place this alongside the *similar* `getFilenameFromUrl` helper function. This way, with the changes in the next patch, we also avoid having to expose the `isDataScheme` function in the API itself and we instead expose `getPdfFilenameFromUrl` in the API (which feels overall more appropriate).
A significant portion of the code-base has now been converted to use `let`/`const`, rather than `var`, hence it should be possible to simply enable the ESLint `no-var` rule globally.
This way we can ensure that new code won't accidentally use `var`, and it also removes the need to manually enable the rule in various folders.
Obviously it makes sense to continue the efforts to replace `var`, but that should probably happen on a file and/or folder basis.
Please note that this patch excludes the following code:
- The `extensions/` folder, since that seemed easiest for now (and I don't know exactly what the support situation is for the Chromium-extension).
- The entire `external/` folder is ignored, since most of it's currently excluded from linting.
For the code that isn't imported from elsewhere (and should be ignored), we should probably (at some point) bring the code up to the same linting/formatting standard as the rest of the code-base.
- Various files in the `test/` folder are ignored, as necessary, since the way that a lot of this code is loaded will require some care (or perhaps larger re-factoring) when removing `var` usage.
- strokeColor corresponds to borderColor;
- support fillColor and textColor;
- support colors on the different annotations;
- fix typo in aforms (+test).
Rather than converting the `AnnotationStorage`-data to an Object, before sending it to the worker-thread, we should be able to simply send the internal `Map` directly.
The "structured clone algorithm" doesn't have a problem with `Map`s, however the `LoopbackPort` used when workers are *disabled* (e.g. in Node.js environments) didn't use to support them. With PR 12997 having lifted that restriction, we should now be able to simply send the `AnnotationStorage`-data as-is rather than having to iterate through it to first create an Object.
*Please note:* The changes in `src/core/annotation.js` could have been a lot more compact if we were able to use optional chaining in the `src/core` folder. Unfortunately that's still not possible, since SystemJS is being used in the development viewer (i.g. `gulp server`) and fixing that is *still* blocked by [bug 1247687](https://bugzilla.mozilla.org/show_bug.cgi?id=1247687).
With the previous patch this function is now *only* accessed on the worker-thread, hence it's no longer necessary to include it in the *built* `pdf.js` file.
With the previous patch this functionality is now *only* accessed on the worker-thread, hence it's no longer necessary to include it in the *built* `pdf.js` file.
The only reason, as far as I can tell, for parsing the Metadata on the main-thread is how it was originally implemented. When Metadata support was first implemented, it utilized the [`DOMParser`](https://developer.mozilla.org/en-US/docs/Web/API/DOMParser) which isn't available in workers.
Today, with the custom XML-parser being used, that's no longer an issue and it seems reasonable to move the Metadata parsing to the worker-thread[1], since that's where all parsing should happen (for performance reasons).
Based on these changes, we'll be able to reduce the now unnecessary duplication of the XML-parser (and related code) in both of the *built* `pdf.js`/`pdf.worker.js` files.
Finally, this patch changes the `_repair` method to use "Array + join" rather than string concatenation.
---
[1] This needed the previous patch, to enable sending of `Map`s between threads with workers disabled.
* don't set a value in annotationStorage by default:
- having an undefined when the annotation is rendered for saving/printing means nothing has changed so use normal appearance
- aims to fix https://bugzilla.mozilla.org/show_bug.cgi?id=1681687
* change the way to compute font size when this one is null in DA:
- make fontSize proportional to line height
- in multiline case, take into account the number of lines for text entered to adapt the font size
