This implementation is inspired by the behaviour in (recent versions of) Adobe Reader, since it leads to reasonably simple and straightforward code as far as I'm concerned.
*Specifically:* We'll only consider *one* destination per page when finding/highlighting the current outline item, which is similar to e.g. Adobe Reader, and we choose the *first* outline item at the *lowest* level of the outline tree.
Given that this functionality requires not only parsing of the `outline`, but looking up *all* of the destinations in the document, this feature can when initialized have a non-trivial performance overhead for larger PDF documents.
In an attempt to reduce the performance impact, the following steps are taken here:
- The "find current outline item"-functionality will only be enabled once *one* page has rendered and *all* the pages have been loaded[1], to prevent it interfering with data regular fetching/parsing early on during document loading and viewer initialization.
- With the exception of a couple of small and simple `eventBus`-listeners, in `PDFOutlineViewer`, this new functionality is initialized *lazily* the first time that the user clicks on the `currentOutlineItem`-button.
- The entire "find current outline item"-functionality is disabled when `disableAutoFetch = true` is set, since it can easily lead to the setting becoming essentially pointless[2] by triggering *a lot* of data fetching from a relatively minor viewer-feature.
- Fetch the destinations *individually*, since that's generally more efficient than using `PDFDocumentProxy.getDestinations` to fetch them all at once. Despite making the overall parsing code *more* asynchronous, and leading to a lot more main/worker-thread message passing, in practice this seems faster for larger documents.
Finally, we'll now always highlight an outline item that the user manually clicked on, since only highlighting when the new "find current outline item"-functionality is used seemed inconsistent.
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[1] Keep in mind that the `outline` itself already isn't fetched/parsed until at least *one* page has been rendered in the viewer.
[2] And also quite slow, since it can take a fair amount of time to fetch all of the necessary `destinations` data when `disableAutoFetch = true` is set.
With the removal of the (standalone) Firefox building code in PR 9566 (a year and a half ago), these files are now completely unused in the GitHub repository[1].
Hence it doesn't really seem necessary to keep fetching them with `gulp importl10n`, and the existing files in the `l10n` folder can also be removed (thanks to version control, they're easy enough to restore should the need ever arise).
The patch also allows an additional simplification, for the `gulp locale` and `gulp mozcentral` commands, since it's now possible to stop writing `l10n` files to the `extensions/firefox/` folder and instead just copy them similar to other build targets.
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[1] They're obviously still used in `mozilla-central`, for fallback messages displayed through `PdfStreamConverter.jsm`, but that doesn't make it necessary to keep them *here* as far as I'm concerned.
With the removal of the (standalone) Firefox building code in PR 9566 (a year and a half ago), these files are now completely unused.
Hence it doesn't really make sense to keep building them as part of `gulp locale`, and the existing files in the `l10n` folder can also be removed (thanks to version control, they're easy enough to restore should the need ever arise).
This includes the information in the core and display layers. The
date parsing logic from the document properties is rewritten according
to the specification and now includes unit tests.
Moreover, missing unit tests for the color of a popup annotation have
been added.
Finally the styling of the popup is changed slightly to make the text a
bit smaller (it's currently quite large in comparison to other viewers)
and to make the drop shadow a bit more subtle. The former is done to be
able to easily include the modification date in the popup similar to how
other viewers do this.
As outlined in https://bugzilla.mozilla.org/show_bug.cgi?id=1282759 the internal Firefox name for the feature is `entireWord`, hence that name is used here as well for consistency (with "Whole words" being limited to the UI).
Given existing limitations of the PDF.js search functionality, e.g. the existing problems of searching across "new lines", there's some edge-cases where "Whole words" searching will ignore (valid) results.
However, considering that this is a pre-existing issue related to the way that the find controller joins text-content together, that shouldn't have to block this new feature in my opionion.
*Please note:* In order to enable this feature in the `MOZCENTRAL` version, a small follow-up patch for [PdfjsChromeUtils.jsm](https://hg.mozilla.org/mozilla-central/file/tip/browser/extensions/pdfjs/content/PdfjsChromeUtils.jsm) will be required once this has landed in `mozilla-central`.
