There's built-in ESLint rule, see `sort-imports`, to ensure that all `import`-statements are sorted alphabetically, since that often helps with readability.
Unfortunately there's no corresponding rule to sort `export`-statements alphabetically, however there's an ESLint plugin which does this; please see https://www.npmjs.com/package/eslint-plugin-sort-exports
The only downside here is that it's not automatically fixable, but the re-ordering is a one-time "cost" and the plugin will help maintain a *consistent* ordering of `export`-statements in the future.
*Note:* To reduce the possibility of introducing any errors here, the re-ordering was done by simply selecting the relevant lines and then using the built-in sort-functionality of my editor.
Given that the PDF document in the issue contains the same very large JPEG image *three* times, this patch includes a test-case where only the first page has been extracted from it.
Add support for finding/highlighting the outlineItem, corresponding to the currently visible page, in the sidebar (issue 7557, bug 1253820, bug 1499050)
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.
Given that the API will now, after PR 12039, automatically pick the correct factories to use depending on the environment (browser vs. Node.js), we can utilize that in the unit-tests as well. This way we don't have to manually repeat the same initialization code in *multiple* unit-tests.
*Note:* The *official* PDF.js API is defined in `src/pdf.js`, hence the new exports in `src/display/api.js` will not affect that.
Also, updates the unit-test `FileReaderFactory` helpers similarily.
*Drive-by change:* Fix the `CMapReaderFactory` usage in the annotation unit-tests, since the cache should only contain raw data and not a Promise. While this obviously works as-is, having unit-tests that "abuse" the intended data format can easily lead to unnecessary failures if changes are made to the relevant `src/core/` code.
Given that we're already using the `external/dist/` folder for things we simply want to copy to pdfjs-dist during building, this patch *should* hopefully work since it's based on the suggestion in issue 12827.
As long as this only requires a *single/small* file, to fix the TypeScript definitions in es5-builds, this solution seem acceptable as far as I'm concerned. (Although, please note that I don't know enough about TypeScript to actually test the patch.)
With the code dispatching a "pageopen" event on the existing (general) `BaseViewer` event "pagesinit", in practice this means that the `Set` is always being created. Hence we can simplify the method overall, by always initializing the `this._pageOpenPendingSet` property.
Given that "pageopen" events are not guaranteed to occur, if the page becomes inactive *before* it finishes rendering, we should probably also avoid dispatching a "pageclose" event in that case to avoid confusing/inconsistent state in any event handlers.
Currently any errors thrown in `preEvaluateFont`, which is a *synchronous* method, will not be handled at all in the `loadFont` method and we were thus failing to return an `ErrorFont`-instance as intended here.
Also, add an *explicit* check in `PartialEvaluator.preEvaluateFont` to ensure that Type0-fonts always have a *valid* dictionary.
Ensure that `PDFViewerApplication._contentLength` is always updated with the *correct* length, as returned by `PDFDocumentProxy.getDownloadInfo`, and only let the `PDFViewerApplication._initializeMetadata` method overwrite if it's not already been set.
Finally, in `PDFViewerApplication._initializeJavaScript`, the fallback `_contentLength` handling is now moved to just after the fallback `documentInfo` handling, such that all the fallback code is in one place within the method.
There's been a number of (somewhat) recent issues where people are having trouble using pdfjs-dist together with `webpack`, since that library purposely doesn't declare any dependencies; refer to PR 11474 for additional context.
In an *attempt*, although I don't know how much this will actually help in practice (given my limited `webpack` experience), let's try to list `worker-loader` as a *peer*-dependency to see if that helps. This should, unless I'm completely misunderstanding https://docs.npmjs.com/cli/v6/configuring-npm/package-json#peerdependencies, prevent `worker-loader` from being installed by default for *all* pdfjs-dist users while still indicating the dependency for those who need it.
Once the next PDF.js release is made, the `webpack` example will no longer work since the non-translated builds now use ECMAScript features not supported by older `webpack`-versions.
With the updated default viewer UI, a couple of `dir`-dependent CSS rules have now become redundant since *identical* rules are being specified for both LTR and RTL mode.
Furthermore, there's also some unnecessary re-defining of the `toolbarButton`/`secondaryToolbarButton`-icon related CSS rules.
Finally, for the toggle-buttons there's a particular styling applied to the `:hover:active` state, however the color wasn't defined with CSS variables.
With the updated default viewer UI, a couple of the toolbarButton icons are now *vertically* symmetrical; hence we can remove some now unneeded `transform: scaleX(-1);` rules from the viewer CSS.
Note how the `onerror` functionality is not being used in the GENERIC `DownloadManager`, since we have no way of knowing if downloading succeeded.
Hence this functionality is only *possibly* useful in MOZCENTRAL builds, however as outlined in the existing comments it's unlikely to be helpful in practice. Generally speaking, if downloading failed once in [`PdfStreamConverter.jsm`](https://searchfox.org/mozilla-central/rev/809ac3660845fef6faf18ec210232fdadc0f1ad9/toolkit/components/pdfjs/content/PdfStreamConverter.jsm#294-406) it seems very likely that it would fail again; all-in-all I'm thus suggesting that we just remove the `onerror` functionality altogether here.
Currently this code is duplicated no less than three times in the `web/app.js` file, and by introducing a helper method we can avoid unnecessary repetition.
There's a fair number of cases where `FirefoxCom.request`-calls are manually wrapped in a Promise to make it asynchronous. We can reduce the amount of boilerplate code in these cases by introducing a new `FirefoxCom.requestAsync` method instead.
Furthermore, a couple of `FirefoxCom.request`-calls in the `DownloadManager` are also changed to be asynchronous rather than using callback-functions.
With this patch, we're thus able to replace a lot of *direct* usages of `FirefoxCom.request` with the new `FirefoxCom.requestAsync` method instead.
*Please note:* It's highly recommended to ignore whitespace-only changes when looking at this patch.
Besides modernizing this code, by converting it to a standard class, the existing JSDoc comments are updated to actually agree better with the way that this functionality is used now. (The next patch will reduce usage of `FirefoxCom.request` significantly, hence the JSDocs for the optional `callback` is removed to not unnecessarily advertise that functionality.)
Finally, the unnecessary/unused `return` statement at the end of `FirefoxCom.request` is also removed.
This is the "modern" way of removing a node from the DOM, which has the benefit of being a lot shorter and more concise.
Also, this patch removes the `return` statement from the "pdf.js.response" event listener, since it's always `undefined`, given that none of the `callback`-functions used here ever return anything (and don't need to either). Generally speaking, returning a value from an event listener isn't normally necessary either.
This method currently accepts a callback-function, which does feel a bit old fashioned now. At the time that this code was introduced, native Promises didn't exist yet and there's a custom Promise-implementation used instead.
However, today with Promises and async/await being used *a lot* it seems reasonable to change `DefaultExternalServices.fallback` to an `async` method instead such that the callback-function can be removed.
