Currently any editing of the preferences require updates in *three* separate files, which isn't a great developer experience to say the least.
This has annoyed me sufficiently to write this patch, which moves the definition of all preferences into `AppOptions` and adds a new `gulp` task to generate the `default_preferences.json` file for the builds where it's needed.
This avoids having the initialization code "spread out", and will become even simpler once the `TODO` is addressed (which I'm planning on fixing as soon as possible).
The intention with preferences such as `sidebarViewOnLoad`/`scrollModeOnLoad`/`spreadModeOnLoad` were always that they should be able to *unconditionally* override their view history counterparts.
Due to the way that these preferences were initially implemented[1], trying to e.g. force the sidebar to remain hidden on load cannot be guaranteed[2]. The reason for this is the use of "enumeration values" containing zero, which in hindsight was an unfortunate choice on my part.
At this point it's also not as simple as just re-numbering the affected structures, since that would wreak havoc on existing (modified) preferences. The only reasonable solution that I was able to come up with was to change the *default* values of the preferences themselves, but not their actual values or the meaning thereof.
As part of the refactoring, the `disablePageMode` preference was combined with the *adjusted* `sidebarViewOnLoad` one, to hopefully reduce confusion by not tracking related state separately.
Additionally, the `showPreviousViewOnLoad` and `disableOpenActionDestination` preferences were combined into a *new* `viewOnLoad` enumeration preference, to further avoid tracking related state separately.
Previously a couple of different attempts at fixing this problem has been rejected, given how *crucial* this code is for the correct function of the viewer, since no one has thus far provided any evidence that the problem actually affects the default viewer[1] nor an example using the viewer components directly (without another library on top).
The fact that none of the prior patches contained even a *simple* unit-test probably contributed to the unwillingness of a reviewer to sign off on the suggested changes.
However, it turns out that it's possible to create a reduced test-case, using the default viewer, that demonstrates the error[2]. Since this utilizes a hidden `<iframe>`, please note that this error will thus affect Firefox as well.
Note that while errors are thrown when the hidden `<iframe>` loads, the default viewer doesn't break completely since rendering does start working once the `<iframe>` becomes visible (although the errors do break the initial Toolbar state).
Before making any changes here, I carefully read through not just the immediately relevant code but also the rendering code in the viewer (given it's dependence on `getVisibleElements`). After concluding that the changes should be safe in general, the default viewer was tested without any issues found. (The above being much easier with significant prior experience of working with the viewer code.)
Finally the patch also adds new unit-tests, one of which explicitly triggers the relevant code-path and will thus fail with the current `master` branch.
This patch also makes `PDFViewerApplication` slightly more robust against errors during document opening, to ensure that viewer/document initialization always completes as expected.
Please keep in mind that even though this patch prevents an error in `getVisibleElements`, it's still not possible to set the initial position/zoom level/sidebar view etc. when the viewer is hidden since rendering and scrolling is completely dependent[3] on being able to actually access the DOM elements.
---
[1] And hence the PDF Viewer that's built-in to Firefox.
[2] Copy the HTML code below and save it as `iframe.html`, and place the file in the `web/` folder. Then start the server, with `gulp server`, and navigate to http://localhost:8888/web/iframe.html
```html
<!DOCTYPE html>
<html>
<head>
<title>Iframe test</title>
<script>
window.onload = function() {
const button = document.getElementById('button1');
const frame = document.getElementById('frame1');
button.addEventListener('click', function(evt) {
frame.hidden = !frame.hidden;
});
};
</script>
</head>
<body>
<button id="button1">Toggle iframe</button>
<br>
<iframe id="frame1" width="800" height="600" src="http://localhost:8888/web/viewer.html" hidden="true"></iframe>
</body>
</html>
```
[3] This is an old, pre-exisiting, issue that's not relevant to this patch as such (and it's already being tracked elsewhere).
This is *really* the best that we can do here, since other proposed solutions would interfere with (and break) the painstakingly implemented browsing history that's present in the default viewer.
I'm still not convinced that this is a good idea in general, but this patch implements it in a way where it is possible to toggle[1] for users that wish to have this feature. In particular, there's a couple of reasons why I'm not finding this feature necessary/great:
- It's already possible to easily obtain the current hash, by simply clicking on the `viewBookmark` button at any time.
- Hash changes requires a bit of special handling[2], i.e. extra code, to prevent issues when the browser history is traversed (see `PDFHistory._popState`). Currently this is only necessary when the user has manually changed the hash, with this patch it will always be the case (assuming the feature is active).
- It's not always possible to change the URL when updating the browser history. For example: In the Firefox built-in viewer, the URL cannot be modified for local files (i.e. those using the `file://` protocol).
This leads to inconsistent behaviour, and may in some cases even result in errors being thrown and the history thus not updating, if the browser prevents changes to the URL during `pushState`/`replaceState` calls.
---
[1] Using the `historyUpdateUrl` viewer preference.
[2] This depends, to a great extent, on browsers always firing `popstate` events *before* `hashchange` events, which may or may not actually be guaranteed.
Given that it's really not clear to me if this is actually desired functionality in the default viewer, and considering that it doesn't fit in *great* with the way that `PDFHistory` is initialized, this feature is currently off by default[1].
---
[1] It's controlled with the `disableOpenActionDestination` Preference/AppOption.
This patch re-factors, and extends, the already existing `zoomDisabledTimeout` used during mouse wheel zooming.
Unfortunately I haven't got the required hardware to actually test this patch, but there's a decent chance that it will fix, or at least reduce, the problems reported in https://bugzilla.mozilla.org/show_bug.cgi?id=1503412.
Rather than having a (somewhat) randomly choosen list of Preferences which `AppOptions` are allowed to override, it makes much more sense to simply add an AppOption to allow custom implementations to ignore Preferences altogether (it's also inline with the AppOption that allows the `ViewHistory` to be bypassed on load).
Rather than closing [bug 1505824](https://bugzilla.mozilla.org/show_bug.cgi?id=1505824) as WONTFIX (which is my preferred solution), given how *minor* this "problem" is, it's still possible to adjust the error messages a bit.
The main point here, which is relevant even if the changes in `BaseViewer` are ultimately rejected during review, is that we'll no longer attempt to call `BaseViewer.currentPageLabel` with an empty string from `webViewerPageNumberChanged` in `app.js`.
The other changes are:
- Stop printing an error in `BaseViewer._setCurrentPageNumber`, and have it return a boolean indicating if the page is within bounds.
- Have the `BaseViewer.{currentPageNumber, currentPageLabel}` setters print their own errors for invalid pages.
- Have the `BaseViewer.currentPageLabel` setter no longer depend, indirectly, on the `BaseViewer.currentPageNumber` setter.
- Improve a couple of other error messages.
This should, hopefully, cover all the possible ways[1] in which "fake workers" are loaded. Given the different code-paths, adding unit-tests might not be that simple.
Note that in order to make this work, the various `fakeWorkerFilesLoader` functions were converted to return `Promises`.
---
[1] Unfortunately there's lots of them, for various build targets and configurations.
Looking at the history of this code, this parameter has never been used.
I'm guessing that most likely the code in `web/toolbar.js` began life as a copy of `web/secondary_toolbar.js`, which would probably explain why that parameter exists.
*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.
---
[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.
This is similar to the format used by a number of other viewer components, and should simplify the `PDFSidebar` initialization slightly.
Furthermore, by using the `eventBus` it's no longer necessary for `PDFSidebar` to have a direct dependency on `PDFOutlineViewer`.
There's still room for improvement here, but this patch is at least a start (since it's not clear to me how best to handle the viewers).
With `PDFFindController` instances no longer (directly) depending on
`BaseViewer` instances, we can pass a single `findController` when
initializing a viewer, similar to other components.
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 way the resetting of `PDFLinkService`/`PDFDocumentProperties` instances, as is done in `PDFViewerApplication.close`, only requires passing in *one* `null` argument instead of two.
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`.
For the `PDFFindBar` implementation, similar to the native Firefox findbar, the matches count displayed is now limited to a (hopefully) reasonable value.
*Please note:* In order to enable this feature in the `MOZCENTRAL` version, a follow-up patch will be required once this has landed in `mozilla-central`.
This patch is the first step to be able to eventually get rid of the `attachDOMEventsToEventBus` function, by allowing `EventBus` instances to simply re-dispatch most[1] events to the DOM.
Note that the re-dispatching is purposely implemented to occur *after* all registered `EventBus` listeners have been serviced, to prevent the ordering issues that necessitated the duplicated page/scale-change events.
The DOM events are currently necessary for the `mozilla-central` tests, see https://hg.mozilla.org/mozilla-central/file/tip/browser/extensions/pdfjs/test, and perhaps also for custom deployments of the PDF.js default viewer.
Once this have landed, and been successfully uplifted to `mozilla-central`, I intent to submit a patch to update the test-code to utilize the new preference. This will thus, eventually, make it possible to remove the `attachDOMEventsToEventBus` functionality.
*Please note:* I've successfully ran all `mozilla-central` tests locally, with these patches applied.
---
[1] The exception being events that originated on the `window` or `document`, since those are already globally available anyway.
The new events follow the same naming pattern as the 'pagesinit'/'pagesloaded' events dispatched on `BaseViewer` instances, and the intention is to allow the eventual removal of 'documentload'.
Given that the various Preferences are currently, and have been for quite some time, only used when initializing `PDFViewerApplication` re-loading them when a new PDF file is opened in the viewer is essentially a no-op.
Furthermore, with the only usage of `BasePreferences.reload` now gone, the value of that method seems questionable at best. In the event that the functionality is actually needed again, similar to the `ViewHistory`, it'd probably make more sense to simply replace `PDFViewerApplication.preferences` with a new `BasePreferences` instance instead (using e.g. `DefaultExternalServices.createPreferences`).
Given that *all* Preferences are already fetched in `PDFViewerApplication._readPreferences`, the amount of boilerplate/duplication can be considerably reduced with the addition of a `BasePreferences.getAll` method.
The only reason that this check ever existed in the first place, is that originally there was a global `PDFJS.openExternalLinkInNewWindow` option which was then subsumed by the (more generic) `PDFJS.externalLinkTarget` option. (The `externalLinkTarget` has since been moved into a `PDFLinkService` option, as part of PDF.js version `2.0`.)
Hence, during the period where both `PDFJS.openExternalLinkInNewWindow` and `PDFJS.externalLinkTarget` existed side-by-side, there was a need to allow the former one to override the latter one (for backward compatibility purposes). However, that's no longer the case, and this extra `externalLinkTarget` check can now be removed.
*This was a stupid error on my part; sorry about breaking this!*
With the current code, the value of the `externalLinkTarget` option is now (potentially) updated *after* the viewer components have been initialized. For the "viewer in iframe/object tag" case, the result is that the value of the `externalLinkTarget` option isn't adjusted as intended any more.
This moves/exposes the `URL` polyfill similarily to the existing `ReadableStream` polyfill, rather than exposing it globally, to avoid interfering with any "outside" code.
Both the `URL` and `ReadableStream` polyfills are now exposed on the `pdfjsLib` object, such that they are accessible to the viewer components.
Furthermore, the `no-restricted-globals` ESLint rule is also enabled to prevent accidental usage of the native `URL`/`ReadableStream` implementations directly in the `src/` and `web/` folders; see also https://eslint.org/docs/rules/no-restricted-globals
Addresses the remaining TODO in https://github.com/mozilla/pdf.js/projects/6
Rather than having to manually call a method on `PDFFindController` instances from `BaseViewer.setDocument`, thus essentially having to resolve the private `_firstPagePromise` from the "outside", this can be done easily with the 'pagesinit' event dispatched on the `eventBus` instead.
Please note this particular `PDFFindController` code pre-dates the `eventBus` by almost three years, which should explain why the code looks the way it does.
Since all the other viewer methods use the getter/setter pattern, e.g. for setting page/scale/rotation, the way that the Scroll/Spread modes are set thus stands out. For consistency, this really ought to use the same pattern as the rest of the `BaseViewer`. (To avoid breaking third-party implementations, the old methods are kept around as aliases.)
Note how the other "...OnLoad" preferences will allow a *non-default* value to always override a history entry. To improve overall consistency for the viewer options, and to reduce possibly confusing behaviour, this patch changes the `scrollModeOnLoad`/`spreadModeOnLoad` preferences to behave as all the other ones.
This property isn't accessed anywhere in the `web/app.js` file, and is also not being reset in `PDFViewerApplication.close`. Hence it seems that it can simply be removed, especially since the fingerprint is already synchronously available through `PDFViewerApplication.pdfDocument.fingerprint` (provided that a document is loaded).
With the current code, the location in the viewer could change *well* after the user has started to interact with the viewer (for very large and/or slow loading documents). Attempt to reduce the likelyhood of that happening, by adding an upper bound to the time spent waiting before attempting to re-apply the initial position.
Rather than using a "special" property to check if a `ViewHistory` database entry existed on load, it seems that you could just as well check for the existence of one of the actually needed properties instead (here 'page' is used).
This way we can avoid storing what, more of less, amounts to useless state, which will help reduce the size of the `ViewHistory` database. Given that we don't directly, nor need to, validate the `ViewHistory` data but rely on other parts of the code-base to do so, the existance of an 'exists' property doesn't in and of itself really add much utility.
Finally, to simplify the implementation the 'exists' property won't be actively removed from the `ViewHistory` data. Instead we'll simply stop adding 'exists' when writing `ViewHistory` data, and rely on the existing pruning of old entries to eventually remove any remnants of 'exists' from storage.
The `onOpenWithURL` method, in `PDFViewerApplication.initPassiveLoading`, accepts a `originalURL` parameter which is then passed on to `PDFViewerApplication.open` as is. However, the latter method expects the name of the parameter to be `originalUrl` (note the casing), meaning that `getDocument` will fail in this case.
For consistency, and to avoid confusion, the renaming is done in `web/chromecom.js` as well.
It appears that Microsoft silently fixed the problem that required disabling of fullscreen mode, in e.g. `iframe`s, in IE 11; please see issue 4711 and PR 5525 for historical context.
Unfortunately my Google-fu isn't strong enough to find any *official* information regarding the fixing of the browser bug in IE. However testing of the default viewer in IE 11, with this patch applied, it now appears that Presentation Mode is working correctly even in an `iframe` in IE 11.
Further anecdotal evidence that the bug is in fact fixed, is for example that jQuery previously contained a work-around for the IE bug. However, that's removed over two years ago now; see ff1a0822f7 and the issues referenced there.
Given that the default viewer isn't intended to be used as-is anyway (in custom deployments), it didn't seem necessary to keep the `disableFullscreen` option around since it was *only* ever added for compatibility purposes.
Fixes 9585.
