This patch is a rebased *and* refactored version of PR 9448, such that it applies cleanly given that `PDFFindController` has changed since that PR was opened; obviously keeping the original author information intact.
This patch will thus ensure that e.g. fractions, and other things that we normalize before searching, will still be highlighted correctly in the textLayer.
Furthermore, this patch also adds basic unit-tests for this functionality.
*Note:* The `[api-minor]` tag is added, since third-party implementations of the `PDFFindController` must now always use the `pageMatchesLength` property to get accurate length information (see the `web/text_layer_builder.js` changes).
Co-authored-by: Ross Johnson <ross@mazira.com>
Co-authored-by: Jonas Jenwald <jonas.jenwald@gmail.com>
Please note that these changes were done automatically, using `gulp lint --fix`.
Given that the major version number was increased, there's a fair number of (primarily whitespace) changes; please see https://prettier.io/blog/2020/03/21/2.0.0.html
In order to reduce the size of these changes somewhat, this patch maintains the old "arrowParens" style for now (once mozilla-central updates Prettier we can simply choose the same formatting, assuming it will differ here).
The correct/intended way of working with the "viewer components" is by providing an `EventBus` instance upon initialization, and the `getGlobalEventBus` was only added for backwards compatibility.
Note, for example, that using `getGlobalEventBus` doesn't really work at all well with a use-case where there's *multiple* `PDFViewer` instances on a one page, since it may then be difficult/impossible to tell which viewer a particular event originated from.
All of the "viewer components" examples have been previously updated, such that there's no longer any code/examples which relies on the now removed `getGlobalEventBus` functionality.
*This is part of a series of patches that will try to split PR 11566 into smaller chunks, to make reviewing more feasible.*
Once all the code has been fixed, we'll be able to eventually enable the ESLint `no-shadow` rule; see https://eslint.org/docs/rules/no-shadow
Since the goal has always been, essentially since the `EventBus` abstraction was added, to remove all dispatching of DOM events[1] from the viewer components this patch tries to address one thing that came up when updating the examples:
The DOM events are always dispatched last, and it's thus guaranteed that all internal event listeners have been invoked first.
However, there's no such guarantees with the general `EventBus` functionality and the order in which event listeners are invoked is *not* specified. With the promotion of the `EventBus` in the examples, over DOM events, it seems like a good idea to at least *try* to keep this ordering invariant[2] intact.
Obviously this won't prevent anyone from manually calling the new *internal* viewer component methods on the `EventBus`, but hopefully that won't be too common since any existing third-party code would obviously use the `on`/`off` methods and that all of the examples shows the *correct* usage (which should be similarily documented on the "Third party viewer usage" Wiki-page).
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[1] Looking at the various Firefox-tests, I'm not sure that it'll be possible to (easily) re-write all of them to not rely on DOM events (since getting access to `PDFViewerApplication` might be generally difficult/messy depending on scopes).
In any case, even if technically feasible, it would most likely add *a lot* of complication that may not be desireable in the various Firefox-tests. All-in-all, I'd be fine with keeping the DOM events only for the `MOZCENTRAL` target and gated on `Cu.isInAutomation` (or similar) rather than a preference.
[2] I wouldn't expect any *real* bugs in a custom implementation, simply based on event ordering, but it nonetheless seem like a good idea if any "external" events are still handled last.
To avoid outright breaking third-party usages of the "viewer components" the `getGlobalEventBus` functionality is left intact, but a deprecation message is printed if the function is invoked.
The various examples are updated to *explicitly* initialize an `EventBus` instance, and provide that when initializing the relevant viewer components.
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`.
This patch makes the follow changes:
- Remove no longer necessary inline `// eslint-disable-...` comments.
- Fix `// eslint-disable-...` comments that Prettier moved down, thus causing new linting errors.
- Concatenate strings which now fit on just one line.
- Fix comments that are now too long.
- Finally, and most importantly, adjust comments that Prettier moved down, since the new positions often is confusing or outright wrong.
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.)
Sometimes we also used `@return` or `@returns`, but `@type` is what
the JSDoc documentation recommends. This also improves the documentation
because before this commit the types were not shown and now they are.
Unless the `PDFLinkService` instance contains all of the expected methods, a lot of things will break in various places in the default viewer. Hence there's not much value in having this check, and outright falling seems more appropriate.
Finally, this also makes the return value explicit in this case, since that's consistent with the rest of the `PDFFindController._shouldDirtyMatch` method.
Only scroll search results into view as a result of an actual find operation, and not when the user scrolls/zooms/rotates the document (bug 1237076, issue 6746)
Most of the code in `PDFFindController` assumes that a valid `state` always exits, hence it cannot hurt to add a simple check to avoid errors being thrown.
Currently searching, and particularily highlighting of search results, may interfere with subsequent user-interactions such as scrolling/zooming/rotating which can result in a somewhat jarring UX where the document suddenly "jumps" to a previous position.
This is especially annoying in cases where the highlighted search result isn't even visible when a user initiated scrolling/zooming/rotating happens, and there exists a couple of bugs/issues about this behaviour.
It seems reasonable, as far as I'm concerned, to treat searching as one operation and any subsequent non-search user interactions with the viewer as separate and thus not scroll the current search result into view *unless* the user is actually doing another search.
This also seems consistent with general searching in e.g. Firefox and Adobe Reader:
- Compare with "regular" searching of e.g. HTML files in Firefox, where the user scrolling and/or zooming the document will not force a currently highlighted search result to become re-scrolled into view.
- Compare also with Adobe Reader, where the user scrolling, zooming, and/or rotating the document will not force the currently highlighted search result to become re-scrolled into view.
The question is then why search highlighting was implemented this way in PDF.js to begin with. It might be that this wasn't really intended behaviour, but more a consequence of the asynchronous nature of the API. Considering that most operations, such as fetching the page, rendering it and extracting its text-content are all asynchronous; searching and highlighting of matches thus becomes asynchronous too.
However, it should be possible to track when search results have been scrolled into view and highlighted, and thus prevent these wierd "jumps" when the user interacts with the document.
*Please note:* Unfortunately this required moving the scrolling of matches back into `PDFFindController`, since I simply couldn't see any other (reasonable) way of implementing the functionality without tracking the `_shouldScroll` property in only *one* spot.
However, given that the new `PDFFindController.scrollMatchIntoView` method follows a similar pattern as `BaseViewer.scrollPageIntoView` and `PDFThumbnailViewer.scrollThumbnailIntoView`, this is hopefully deemed OK.
Currently we'll only attempt to start from the current page when a new search is done, however for 'findagain' operations we'll always continue from the last match position.
This could easily lead to confusing behaviour if the user has scrolled to a completely different part of the document. In an attempt to improve this somewhat, for repeated 'findagain' operations, we'll instead reset the position to the current page when it's *absolutely* certain that the user has scrolled.
Note that this required adding a new `BaseViewer` method, and exposing that through `PDFLinkService`, in order to check if a given page is visible.
In an attempt to avoid issues, in custom implementations of `PDFFindController`, the code checks for the existence of the `PDFLinkService.isPageVisible` method *before* using it.
Unfortunately the `PDFFindController.executeCommand` method has now become a bit more complicated than one would like, but hopefully this small change will improve the structure somewhat (especially for subsequent patches).
Currently `PDFFindController._calculateMatch` is (indirectly) dispatching an `updatetextlayermatches` event for every *single* page of the document. For short documents, such as the `tracemonkey` file, this probably doesn't matter too much, but for documents with a couple of thousand pages it seems unfortunate.
It shouldn't be necessary, in general, to dispatch `updatetextlayermatches` events here, since that's already being taken care of in `PDFFindController._updateMatch` which is always called when a match has been found.
However, when `highlightAll` is set we still need to ensure that pages which finished rendered *before* searching begun are updated correctly.
**STR:**
1. Open the default viewer, with the `tracemonkey` file.
2. Open the findbar, and search for "trace".
3. Enable the "Highlight All" option.
4. Close the findbar.
5. Re-open the findbar, and click on the "findNext" button.
6. Scroll down to the *second* page of the document.
**ER:**
Since "Highlight All" is active, all matches on the *second* page should be highlighted.
**AR:**
No matches are highlighted on the *second* page.
For a short document, such as e.g. the `tracemonkey` file, this repeated normalization won't matter much, but for documents with a couple of thousand pages it seems completely unnecessary (and wasteful) to keep repeating the normalization whenever for every single page.
Currently the text-content is normalized every time that a new search operation is started, which seems completely useless considering that the "raw" text-content is never used for anything.
For a short document, such as e.g. the `tracemonkey` file, this repeated normalization won't matter much, but for documents with a couple of thousand pages it seems completely unnecessary (and wasteful) to keep repeating the normalization whenever e.g. a new search operation starts.
In the event that multiple instances of `PDFFindController` ever exists simultaneously, they will all be able to share just one `normalize` function in this way. Furthermore, the regular expression is now created lazily rather than at class construction time.
Despite all highlighted matches being removed in response to the 'findbarclose' event, there's a risk that a match could still be scrolled into view *after* the findbar has been closed[1].
Hence we need to ensure that long running searches, particularily those happening in large and/or slow loading documents[2], are ignored as well.
---
[1] The match is hidden, as expected, but the document could still scroll unexpectedly.
[2] Large documents loaded with `disableAutoFetch = true` and `disableStream = true` set are particularily susceptible to this issue.
Given that dispatching the 'updatetextlayermatches' event with `pageIndex = -1` set is now used to target the textLayers of *all* pages, there's no need to send individual events to every single page during `_nextMatch`. Since there can be an arbitrary number of pages in a document, this small/simple optimization seems too easy to ignore.
This patch does four things:
- Change the search related methods in `TextLayerBuilder` to be "private", since there're only called from within the class itself now.
- Use `const` for local variables not intended to change in the search related methods in `TextLayerBuilder`.
- Finally, removes most `this.findController` checks since they are redundant. Note how both `this._convertMatches` and `this._renderMatches` are *only* ever called, from `this._updateMatches`, when `this.findController` is actually defined. Hence there's really no need to repeat those checks all over the place, especially with all the relevant methods now being marked as "private".
- Always initialize the `this._pageMatchesLength` property with an empty array, to simplify the code in `TextLayerBuilder`.
*This patch is based on something that I noticed while working on PR 10126.*
The recent re-factoring of `PDFFindController` brought many improvements, among those the fact that access to `BaseViewer` is no longer required. However, with these changes there's one thing which now strikes me as not particularly user-friendly[1]: The fact that in order for searching to actually work, `PDFFindController.setDocument` must be called *and* a 'pagesinit' event must be dispatched (from somewhere).
For all other viewer components, calling the `setDocument` method[2] is enough in order for the component to actually be usable.
The `PDFFindController` thus stands out quite a bit, and it also becomes difficult to work with in any sort of custom implementation. For example: Imagine someone trying to use `PDFFindController` separately from the viewer[3], which *should* now be relatively simple given the re-factoring, and thus having to (somehow) figure out that they'll also need to manually dispatch a 'pagesinit' event for searching to work.
Note that the above even affects the unit-tests, where an out-of-place 'pagesinit' event is being used.
To attempt to address these problems, I'm thus suggesting that *only* `setDocument` should be used to indicate that searching may start. For the default viewer and/or the viewer components, `BaseViewer.setDocument` will now call `PDFFindController.setDocument` when the document is ready, thus requiring no outside configuration anymore[4]. For custom implementation, and the unit-tests, it's now as simple as just calling `PDFFindController.setDocument` to allow searching to start.
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[1] I should have caught this during review of PR 10099, but unfortunately it's sometimes not until you actually work with the code in question that things like these become clear.
[2] Assuming, obviously, that the viewer component in question actually implements such a method :-)
[3] There's even a very recent issue, filed by someone trying to do just that.
[4] Short of providing a `PDFFindController` instance when creating a `BaseViewer` instance, of course.
Since searching itself is an asynchronous operation, removal of highlights needs to be asynchronous too since otherwise there's a risk that the events happen in the wrong order and find highlights thus remain visible.
Also, this patch will now ensure that only 'findbarclose' events for the *current* document is handled since other ones doesn't really matter. Note in particular that when no document is loaded text-layers are, obviously, not present and subsequently it's unnecessary to attempt to hide non-existent find highlights.
For many years it's been possible to enter a search term into the findbar(s) before the document has finised loading, such that searching starts immediately once it has loaded.
PR 10099 accidentally broke that, which I unfortunately missed during reviewing.
Since searching is asynchronous you cannot directly check in `executeCommand` if the document is loaded/current, but need to wait until searching is actually enabled first.
Furthermore this patch also ensures that the `_findTimeout` is always correctly cleared given that it adds further asynchronous behaviour to searching, since you obviously only want to deal with searches relevant to the current document.
This commit shows that we can now unit test the find controller and
that executing regular queries works. Note that this is only a first
step and not a complete suite of unit tests for all possible options
of the find controller.
While writing this unit test, I found two smaller issues that I
addressed directly. The first one is that in the previous find
controller refactoring I forgot to rename some occurrences of a now
private member variable. Fortunately this did not cause any bugs since
we did have a public getter and the fetched value may be changed by
reference, but it's nevertheless good to fix. The second issue is that
some entries in the `test/unit/clitests.json` file were not correct,
resulting in these tests not being executed on e.g., Travis CI.
This removes the dependency on a `PDFViewer` instance from the find
controller, which makes it more similar to other components and makes it
easier to unit test with a mock link service.
Finally, we remove the search capabilities from the SVG example since it
doesn't work there because there is no separate text layer.
Now it follows the same pattern as e.g., the document properties
component, which allows us to have one instance of the find controller
and set a new document to search upon switching documents.
Moreover, this allows us to get rid of the dependency on `pdfViewer` in
order to fetch the text content for a page. This is working towards
getting rid of the `pdfViewer` dependency upon initializing the
component entirely in future commits.
Finally, we make the `reset` method private since it's not supposed to
be used from the outside anymore now that `setDocument` takes care of
this, similar to other components.
This prevents the findbar from intermittently displaying `0 of {number} matches`, which *could* theoretically happen for large and/or slow loading documents.
The find controller should only coordinate finding a string in the
document and should not be responsible for presenting the matches to the
user. The text layer builder already contains the logic to render the
matches in the viewer, so it should also take care of scrolling the
selected match into view.
The find controller already has quite a lot of state to maintain. We can
avoid keeping track of this member variable because when the find
controller is reset, so is the extract text promises array. Therefore,
we can just check if that array contains items or not to determine if
text extraction already started.
Moreover, there is no need to reset the `pageContents` array since the
`reset` method already takes care of that.
