While this doesn't actually fix the underlying issue, it should prevent the ESLint errors and thus make future PDF.js updates easier.
Compared to updating (and testing) the preprocessor, this seems like a reasonable workaround given its simplicity.
See Bug 1389443 for more information. This allows us to register
PdfJs without waiting for file IO in nsHandlerService to finish.
Once that file IO is finished, we can set everything up properly
and double-check the registration.
http://eslint.org/docs/rules/comma-danglehttp://eslint.org/docs/rules/object-curly-spacing
Given that we currently have quite inconsistent object formatting, fixing this in in one big patch probably wouldn't be feasible (since I cannot imagine anyone wanting to review that); hence I've opted to try and do this piecewise instead.
Please note: This patch was created automatically, using the ESLint `--fix` command line option. In a couple of places this caused lines to become too long, and I've fixed those manually; please refer to the interdiff below for the only hand-edits in this patch.
```diff
diff --git a/extensions/firefox/content/PdfStreamConverter.jsm b/extensions/firefox/content/PdfStreamConverter.jsm
index ea91a71a..0d59dad1 100644
--- a/extensions/firefox/content/PdfStreamConverter.jsm
+++ b/extensions/firefox/content/PdfStreamConverter.jsm
@@ -773,7 +773,8 @@ class RequestListener {
response = function sendResponse(aResponse) {
try {
var listener = doc.createEvent("CustomEvent");
- let detail = Cu.cloneInto({ response: aResponse, }, doc.defaultView);
+ let detail = Cu.cloneInto({ response: aResponse, },
+ doc.defaultView);
listener.initCustomEvent("pdf.js.response", true, false, detail);
return message.dispatchEvent(listener);
} catch (e) {
```
This is a downstream change introduced in [1]. That mozilla bug is adding a new property to channel's loadinfo object (nsILoadInfo) that protocol handlers has to set on channels when originalURI on the result channel is set to a different URI than the channel has been created for.
Existence of the new property on nsILoadInfo depends on landing [1].
[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1319111
Please note that I used the addon debugger to set a breakpoint in the `unload` function, in order to ensure that `this` still correctly refers to the `FindEventManager` scope.
In https://bugzilla.mozilla.org/show_bug.cgi?id=1355216, the *third* parameter of `Services.obs.addObserver` was made optional.
However, omitting it in Firefox versions *without* that patch causes failures that completely prevents the addon from working (it won't even load).
As far as I can tell, there isn't *any* way to detect ahead of time if the third parameter can be safely omitted, hence we're forced to fallback to manually checking the version number :-(
*Note:* Since the `PdfJs.jsm` file is only used in the `MOZCENTRAL` build, we at least don't need to add any compatibility hacks there.
If we only invoke the bootstrap-enabled script when PdfJs.enabled is
true, then we don't need to check it again in the script.
This avoids a sync IPC call to the parent process.
It also keeps PdfJs.jsm from importing PdfjsContentUtils.jsm in the
child process until it is actually needed, which is one steps towards
not loading it until it is really needed.
pdfjschildbootstrap.js will always be run, but
pdfjschildbootstrap-enabled.js will only be run if PdfJs.enabled is
true. This will let us avoid some work in the child process in the
next patch.
This will need to be landed in the mozilla-central repository at the
same time as a change to nsBrowserGlue.js. See bug 1352218.
The last (and only) usage of `MOZ_CENTRAL` was removed in PR 3036, so it's been unused for almost four years now.
If we need to have different code-paths for `FIREFOX`/`MOZCENTRAL` builds, the preprocessor should (and has) been used instead.
Given that this patch causes a lot of churn in the addon code, I wouldn't really mind if we ultimately decide against doing this and just add a rule exception in mozilla-central instead.[1]
---
[1] Note that I used the ESLint `--fix` option, hence writing this commit message actually took longer time than the creation of the patch :-)
PR 7322 added the `PdfJsNetwork.jsm` file, instead of the general `src/core/network.js` file for the Firefox addon. However, `make.js` wasn't updated to actually stop including the now obsolete network file.
*Please note: ignoring whitespace changes is most likely necessary for the diff to be readable.*
This patch addresses all the current, in `mozilla-central`, linting failures in the addon. It should thus be possible to change the `.eslintignore` entry for PDF.js in `mozilla-central` from `browser/extensions/pdfjs/**` to `browser/extensions/pdfjs/build/**` and `browser/extensions/pdfjs/web/**` instead.
Note that we cannot, for backwards compatibility reason of the general PDF.js library, at this time make similar changes for files residing in the `build` and `web` directories in `mozilla-central`.
The main changes in this patch are that we now use [classes](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes) instead of our previous "class-like" functions, and also use the more compact [object shorthand notation](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Operators/Object_initializer#New_notations_in_ECMAScript_2015).
A couple of functions were also converted to [arrow functions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions), to reduced usages of `bind(this)` and `var self = this`.
One caveat with ES6 classes is that it's not (yet) possible to define private constants/helper functions within them, which is why the `NetworkManagerClosure` was kept to not change the visibility of those constant/functions.
Besides testing in Firefox Nightly 53, this patch has also been tested in Firefox ESR 45 and SeaMonkey 2.46.
However, I'd gladly welcome help with testing the patch more, to ensure that nothing has gone wrong during the refactoring.
Fixes the first bullet point of issue 7957.
According to https://wiki.mozilla.org/RapidRelease/Calendar#Past_branch_dates: The *last* ESR version of Firefox 38 was released in April this year, and since June the only available ESR version has been based on Firefox 45.
Now that Seamonkey has *finally* released a new version, i.e. 2.46 which should correspond to Firefox 49, there doesn't seem to be any reason to keep the fallback code around in the addon anymore.
*Please note that most of the necessary code adjustments were made in PR 7890.*
ESLint has a number of advantageous properties, compared to JSHint. Among those are:
- The ability to find subtle bugs, thanks to more rules (e.g. PR 7881).
- Much more customizable in general, and many rules allow fine-tuned behaviour rather than the just the on/off rules in JSHint.
- Many more rules that can help developers avoid bugs, and a lot of rules that can be used to enforce a consistent coding style. The latter should be particularily useful for new contributors (and reduce the amount of stylistic review comments necessary).
- The ability to easily specify exactly what rules to use/not to use, as opposed to JSHint which has a default set. *Note:* in future JSHint version some of the rules we depend on will be removed, according to warnings in http://jshint.com/docs/options/, so we wouldn't be able to update without losing lint coverage.
- More easily disable one, or more, rules temporarily. In JSHint this requires using a numeric code, which isn't very user friendly, whereas in ESLint the rule name is simply used instead.
By default there's no rules enabled in ESLint, but there are some default rule sets available. However, to prevent linting failures if we update ESLint in the future, it seemed easier to just explicitly specify what rules we want.
Obviously this makes the ESLint config file somewhat bigger than the old JSHint config file, but given how rarely that one has been updated over the years I don't think that matters too much.
I've tried, to the best of my ability, to ensure that we enable the same rules for ESLint that we had for JSHint. Furthermore, I've also enabled a number of rules that seemed to make sense, both to catch possible errors *and* various style guide violations.
Despite the ESLint README claiming that it's slower that JSHint, https://github.com/eslint/eslint#how-does-eslint-performance-compare-to-jshint, locally this patch actually reduces the runtime for `gulp` lint (by approximately 20-25%).
A couple of stylistic rules that would have been nice to enable, but where our code currently differs to much to make it feasible:
- `comma-dangle`, controls trailing commas in Objects and Arrays (among others).
- `object-curly-spacing`, controls spacing inside of Objects.
- `spaced-comment`, used to enforce spaces after `//` and `/*. (This is made difficult by the fact that there's still some usage of the old preprocessor left.)
Rules that I indend to look into possibly enabling in follow-ups, if it seems to make sense: `no-else-return`, `no-lonely-if`, `brace-style` with the `allowSingleLine` parameter removed.
Useful links:
- http://eslint.org/docs/user-guide/configuring
- http://eslint.org/docs/rules/
From the discussion in issue 7386, it wasn't really clear if we can restrict addon support to Firefox `45` (i.e. the version that corresponds to the *current* ESR version).
However, we have a bunch of code for *very* old Firefox versions. Hence this patch changes the minimum supported version to Firefox `38` (which was released on `2015-05-12`, and correspond to the *previous* ESR version), and removes code that only applies to old Firefox versions.
Regardless what we end up deciding regarding addon support for previous Firefox versions, given the amount of code that even the Firefox `>= 38` condition lets us remove, I certainly think that there is value in doing this.
