Up until recently, anytime you pushed a patch series to MozReview, a single attachment would be created on the bug associated with the push.
That single attachment would link to the “parent” or “root” review request, which contains the folded diff of all commits.
We noticed a lot of MozReview users were (rightfully) confused about this mapping from Bugzilla to MozReview. It was not at all obvious that Ship It on the parent review request would cause the attachment on Bugzilla to be r+’d. Consequently, reviewers used a number of workarounds, including, but not limited to:
- Manually setting the r+ or r- flags in Bugzilla for the MozReview attachments
- Marking Ship It on the child review requests, and letting the reviewee take care of setting the reviewer flags in the commit message
- Just writing “r+” in a MozReview comment
Anyhow, this model wasn’t great, and caused a lot of confusion.
So it’s changed! Now, when you push to MozReview, there’s one attachment created for every commit in the push. That means that when different reviewers are set for different commits, that’s reflected in the Bugzilla attachments, and when those reviewers mark “Ship It” on a child commit, that’s also reflected in an r+ on the associated Bugzilla attachment!
I think this makes quite a bit more sense. Hopefully you do too!
I’m on vacation this week, but the show must go on! So I pre-recorded a shorter episode of The Joy of Coding last Friday.
I demo the tool, and then I explain how it works. After I finished the episode, I pushed to repository to GitHub, and you can check that out right here.
So I’ll see you next week with a full length episode! Take care!
Which, several times, I mistakenly refer to as the 15th episode, and not the 16th. Whoops. ↩
Common (excluding Website bugs)-specific: (23)
- Fixed: 768207 – Make the cache checkbox default-on in the new calendar dialog
- Fixed: 1049591 – Fix lots of strict warnings
- Fixed: 1086573 – Lightning and Thunderbird disagree about timezone support in ics files
- Fixed: 1099592 – Make JS callers of ios.newChannel call ios.newChannel2 in calendar/
- Fixed: 1149423 – Add Windows timezone names to list of aliases
- Fixed: 1151011 – Calendar events show up on wrong day when printing
- Fixed: 1151440 – Choose a color not responsive when creating a New calendar in Lightning 4.0b1
- Fixed: 1153327 – Run compare-locales with merging for Lightning
- Fixed: 1156015 – Email scheduling fails for recipients with URN id
- Fixed: 1158036 – Support sendMailTo for URN type attendees
- Fixed: 1159447 – TEST-UNEXPECTED-FAIL | xpcshell-icaljs.ini:calendar/test/unit/test_extract.js
- Fixed: 1159638 – Getter fails in calender-migration-dialog on first run after installation
- Fixed: 1159682 – Provide a more appropriate “learn more” page on integrated Lightning firstrun
- Fixed: 1159698 – Opt-out dialog has a button for “disable”, but actually the addon is removed
- Fixed: 1160728 – Unbreak Lightning 4.0b4 beta builds
- Fixed: 1162300 – TEST-UNEXPECTED-FAIL | xpcshell-libical.ini:calendar/test/unit/test_alarm.js | xpcshell return code: 0
- Fixed: 1163306 – Re-enable libical tests and disable ical.js in nightly builds when binary compatibility is back
- Fixed: 1165002 – Lightning broken, tries to load libical backend although “calendar.icaljs” defaults to “true”
- Fixed: 1165315 – TEST-UNEXPECTED-FAIL | xpcshell-icaljs.ini:calendar/test/unit/test_bug759324.js | xpcshell return code: 1 | ###!!! ASSERTION: Deprecated, use NewChannelFromURI2 providing loadInfo arguments!
- Fixed: 1165497 – TEST-UNEXPECTED-FAIL | xpcshell-icaljs.ini:calendar/test/unit/test_alarmservice.js | xpcshell return code: -11
- Fixed: 1165726 – TEST-UNEXPECTED-FAIL | /builds/slave/test/build/tests/mozmill/testBasicFunctionality.js | testBasicFunctionality.js::testSmokeTest
- Fixed: 1165728 – TEST-UNEXPECTED-FAIL | xpcshell-icaljs.ini:calendar/test/unit/test_bug494140.js | xpcshell return code: -11
Sunbird will no longer be actively developed by the Calendar team.
- Fixed: 401779 – Integrate Lightning Into Thunderbird by Default and Ship Thunderbird with Lightning Enabled
- Fixed: 717292 – Spell check language setting for subject and body not synchronized, but temporarily appears so when changing language and depending on focus (confusing ux)
- Fixed: 914225 – Support hotfix add-on in Thunderbird
- Fixed: 1025547 – newmailaccount/jquery.tmpl.js, line 123: reference to undefined property def
- Fixed: 1088975 – Answering mail with sendername containing encoded special chars and comma creates two “To”-entries
- Fixed: 1101237 – Remove distribution directory during install
- Fixed: 1109178 – Thunderbird OAuth implementation does not work with Evernote
- Fixed: 1110166 – Port |Bug 1102219 – Rename String.prototype.contains to String.prototype.includes| to comm-central
- Fixed: 1113097 – Fix misuse of fixIterator
- Fixed: 1130854 – Package Lightning with Thunderbird
- Fixed: 1131997 – Adapt for Debugger Server code for changes in bug 1059308
- Fixed: 1135291 – Update chat log entries added to Gloda since bug 955292 to use relative paths
- Fixed: 1135588 – New conversations get indexed twice by gloda, leading to duplicate search results
- Fixed: 1138154 – Plugins default to “always activate” in Thunderbird
- Fixed: 1142879 – [meta] track Mozilla-central (Core) issues that we want to have fixed in TB38
- Fixed: 1146698 – Chat Messages added to logs just before shutdown may not be indexed by gloda
- Fixed: 1148330 – Font indicator doesn’t update when cursor is placed in text where core returns sans-serif (Windows). Serif and monospace don’t work (Linux).
- Fixed: 1148512 – TEST-UNEXPECTED-FAIL | mailnews/imap/test/unit/test_dod.js | xpcshell return code: 0||1 | streamMessages – [streamMessages : 94] false == true | application crashed [@ mozalloc_abort(char const * const)]
- Fixed: 1149059 – splitter in compose window can be resized down to completely obscure composition area
- Fixed: 1151206 – Using a theme hides minimize, maximize and close button in composer window [Mac]
- Fixed: 1151475 – Remove use of expression closures in mail/
- Fixed: 1152299 – [autoconfig] Cosmetic changes for WEB.DE config
- Fixed: 1152706 – Upgrade to Correspondents column (combined To/From column) too agressive
- Fixed: 1152796 – chrome://messenger/content/folderDisplay.js, line 697: TypeError: this._savedColumnStates.correspondentCol is undefined
- Fixed: 1152926 – New mail sound preview doesn’t work for default system sound on Mac OS X
- Fixed: 1154737 – Permafail: TEST-UNEXPECTED-FAIL | toolkit/components/telemetry/tests/unit/test_TelemetryPing.js | xpcshell return code: 0
- Fixed: 1154747 – TEST-UNEXPECTED-FAIL | /builds/slave/test/build/tests/mozmill/session-store/test-session-store.js | test-session-store.js::test_message_pane_height_persistence
- Fixed: 1156669 – Trash folder duplication while using IMAP with localized TB
- Fixed: 1157236 – In-content dialogs: Port bug 1043612, bug 1148923 and bug 1141031 to TB
- Fixed: 1157649 – TEST-UNEXPECTED-FAIL | dom/push/test/xpcshell/test_clearAll_successful.js (and most other push tests)
- Fixed: 1158824 – Port bug 138009 to fix packaging errors | Missing file(s): bin/defaults/autoconfig/platform.js
- Fixed: 1159448 – Thunderbird ignores proxy settings on POP3S protocol
- Fixed: 1159627 – resource:///modules/dbViewWrapper.js, line 560: SyntaxError: unreachable code after return statement
- Fixed: 1159630 – components/glautocomp.js, line 155: SyntaxError: unreachable code after return statement
- Fixed: 1159676 – mailnews/mime/jsmime/test/test_custom_headers.js | run_next_test 0 – TypeError: _gRunningTest is undefined at /builds/slave/test/build/tests/xpcshell/head.js:1435 (and other jsmime tests)
- Fixed: 1159688 – After switching/changing the window layout, dragging the splitter between threadpane and messagepane can create gray/grey area/space (misplaced notificationbox)
- Fixed: 1159815 – Take bug 1154791 “Inline spell checker loses red underlines after a backspace is used – take two” in Thunderbird 38
- Fixed: 1159817 – Take “Bug 1100966 – Inline spell checker loses red underlines after a backspace is used” in Thunderbird 38
- Fixed: 1159834 – Consider taking “Bug 756984 – Changing location in editor doesn’t preserve the font when returning to end of text/line” in Thunderbird 38
- Fixed: 1159923 – Take bug 1140105 “Can’t query for a specific font face when the selection is collapsed” in TB 38
- Fixed: 1160105 – Fix strict mode warnings in protovis-r2.6-modded.js
- Fixed: 1160106 – “Searching…” spinner at the bottom of gloda search results never goes away
- Fixed: 1160114 – Strict mode warnings on faceted search
- Fixed: 1160805 – Missing Windows and Linux nightly builds, build step set props: previous_buildid fails
- Fixed: 1161162 – “Join Chat” doesn’t focus the newly joined MUC
- Fixed: 1162396 – Take bug 1140617 “Pasting an image loses the composition style” in TB38
- Fixed: 1163086 – Take bug 967494 “changing spellcheck language in one composition window affects all open and new compositions” in TB38
- Fixed: 1163299 – “TypeError: getBrowser(…) is null” in contentAreaClick with Lightning installed and started in calendar view
- Fixed: 1163343 – Incorrectly formatted error message “sending failed”
- Fixed: 1164415 – Error in comment for imapEnterServerPasswordPrompt
- Fixed: 1164658 – TypeError: Cc[‘@mozilla.org/weave/service;1’] is undefined at resource://gre/modules/FxAccountsWebChannel.jsm:227
- Fixed: 1164707 – missing toolkit_perfmonitoring.xpt in aurora builds
- Fixed: 1165152 – Take bug 1154894 in TB 38 branch: Disable test_plugin_default_state.js so Thunderbird can ship with plugins disabled by default
- Fixed: 1165320 – TEST-UNEXPECTED-FAIL | /builds/slave/test/build/tests/mozmill/notification/test-notification.js
MailNews Core-specific: (30)
- Fixed: 610533 – crash [@ nsMsgDatabase::GetSearchResultsTable(char const*, int, nsIMdbTable**)] with virtual folder
- Fixed: 745664 – Rename Address book aaa to aaa_test, delete another address book bbb, and renamed address book aaa_test will lose its name and appear deleted after restart (dataloss! involving localized names)
- Fixed: 777770 – get rid of nsVoidArray from /mailnews
- Fixed: 786141 – Use nsIFile.exists() instead of stat to check the existence of the file
- Fixed: 1069790 – Email addresses with parenthesis are not pretty-printed anymore
- Fixed: 1072611 – Ctrl+P not working from Composition’s Print Preview window
- Fixed: 1099587 – Make JS callers of ios.newChannel call ios.newChannel2 in mail/ and mailnews/
- Fixed: 1130248 – |To: “firstname.lastname@example.org” <email@example.com>| becomes |”firstname.lastname@example.org”@example.com| when I compose mail to it
- Fixed: 1138220 – some headers are not not properly capitalized
- Fixed: 1141446 – Behaviour of malformed rfc2047 encoded From message header inconsistent
- Fixed: 1143569 – User-agent error when posting to NNTP due to RFC5536 violation of Tb (user-agent header is folded just after user-agent:, “user-agent:[CRLF][SP]Mozilla…”)
- Fixed: 1144693 – Disable libnotify usage on Linux by default for new-mail notifications (doesn’t always work after bug 858919)
- Fixed: 1149320 – fix compile warnings in mailnews/extensions/
- Fixed: 1150891 – Port package-manifest.in changes from Bug 1115495 – Part 2: PAC generator for browsing and system wide proxy
- Fixed: 1151782 – Inputting 29th Feb as a birthday in the addressbook contact replaces it with 1st Mar.
- Fixed: 1152364 – crash in Address Book via nsAbBSDirectory::GetChildNodes nsCOMArrayEnumerator::operator new(unsigned int, nsCOMArray_base const&)
- Fixed: 1152989 – Account Manager Extensions broken in Thunderbird 37/38
- Fixed: 1154521 – jsmime fails on long references header and e-mail gets sent and stored in Sent without headers
- Fixed: 1155491 – Support autoconfig and manual config of gmail IMAP OAuth2 authentication
- Fixed: 1155952 – Nesting level does not match indentation
- Fixed: 1156691 – GUI “Edit filters”: Conditions/actions (for specfic accounts) not visible
- Fixed: 1156777 – nsParseMailbox.cpp:505:55: error: ‘do_QueryObject’ was not declared in this scope
- Fixed: 1158501 – Port bug 1039866 (metro code removal) and bug 1085557 (addition of socorro symbol upload API)
- Fixed: 1158751 – Port NO_JS_MANIFEST changes | mozbuild.frontend.reader.SandboxValidationError: calendar/base/backend/icaljs/moz.build
- Fixed: 1159255 – Build error: MSVC_ENABLE_PGO = True is not permitted to be used in mailnews/intl/moz.build
- Fixed: 1159626 – chrome://messenger/content/accountUtils.js, line 455: SyntaxError: unreachable code after return statement
- Fixed: 1160647 – Port |Bug 1159972 – Remove the fallible version of PL_DHashTableInit()| to comm-central
- Fixed: 1163347 – Don’t require scope in ispdb config for OAuth2
- Fixed: 1165737 – Fix usage of NS_LITERAL_CSTRING in mailnews, port Bug 1155963 to comm-central
- Fixed: 1166842 – Re-enable binary extensions for comm-central
You might have noticed that I had no “Things I’ve Learned This Week” post last week. Sorry about that – by the end of the week, I looked at my Evernote of “lessons from the week”, and it was empty. I’m certain I’d learned stuff, but I just failed to write it down. So I guess the lesson I learned last week was, always write down what you learn.How to make your mozilla-central Mercurial clone work faster
I like Mercurial. I also like Git, but recently, I’ve gotten pretty used to Mercurial.
One complaint I hear over and over (and I’m guilty of it myself sometimes), is that “Mercurial is slow”. I’ve even experienced that slowness during some of my Joy of Coding episodes.
This document did not exist when I first started working with Mercurial – back then, I was using mq or sometimes pbranch, and grumbling about how I missed Git.
But there is some gold in this document.
gps has been doing some killer work documenting best practices with Mercurial, and this document is one of the results of his labour.
watchman is a tool that some folks at Facebook wrote to monitor changes in a folder. hgwatchman is an extension for Mercurial that takes advantage of watchman for a repository, smartly precomputing a bunch of stuff when the folder changes so that when you fire a command, likehg status
It takes a fraction of the time it’d take without hgwatchman. A fraction.
Here’s how I set hgwatchman up on my MacBook (though you should probably go by the Mercurial for Mozillians doc as the official reference):
- Install watchman with brew: brew install watchman
- Clone the hgwatchman extension to some folder that you can easily remember and build it: hg clone https://bitbucket.org/facebook/hgwatchman cd hgwatchman make local
- Add the following lines to my user .hgrc: [extensions] hgwatchman = cloned-in-dir/hgwatchman/hgwatchman
- Make sure the extension is properly installed by running: hg help extensions
- hgwatchman should be listed under “enabled extensions”. If it didn’t work, keep in mind that you want to target the hgwatchman directory
- And then in my mozilla-central .hg/.hgrc: [watchman] mode = on
- Boom, you’re done!
Congratulations, hg should feel snappier now!
On Firefox Hello, we recently added the eslint linter to be run against the Hello code base. We started of with a minimal set of rules, just enough to get us something running. Now we’re working on enabling more rules.
Since we enabled it, I feel like I’m able to iterate faster on patches. For example, if just as I finish typing I see something like:
Now I think about it, I’m realising it has also helped reduced the amount of review nits on my patches – due to trivial formatting mistakes being caught automatically, e.g. trailing white-space or missing semi-colons.
Talking about reviews, as we’re running eslint on the Hello code, we just have to apply the patch, and run our tests, and we automatically get eslint output:
Hopefully our patch authors will be running eslint before uploading the patch anyway, but this is an additional test, and a few less things that we need to look at during review which helps speed up that cycle as well.
I’ve also put together a global config file for eslint (see below), that I use for outside of the Hello code, on the rest of the Firefox code base (and other projects). This is enough, that, when using it in my editor it gives me a reasonable amount of information about bad syntax, without complaining about everything.
I would definitely recommend giving it a try. My patches feel faster overall, and my test runs are for testing, not stupid-mistake catching!
Want more specific details about the setup and advantages? Read on…
You need to have eslint installed globally, or at least in your path, other than that, just follow the installation instructions given on the SublimeLinter page.
One configuration I change I did have to make to the global configuration:
- Select “Preferences” -> “Settings – More” -> “Syntax Specific – User”
- In the file that appears, set the configuration up as follows (or whatever suits you):
I’ve uploaded my global configuration to a gist, if it changes I’ll update it there. It isn’t intended to catch everything – there’s too many inconsistencies across the code base for that to be sensible at the moment. However, it does at least allow general syntax issues to be highlighted for most files – which is obviously useful in itself.
I haven’t yet tried running it across the whole code base via eslint on the command line – there seems to be some sort of configuration issue that is messing it up and I’ve not tracked it down yet.
Firefox Hello’s Configuration
The configuration files for Hello can be found in the mozilla-central source. There’s a few of these because we have both content and chrome code, and some of the content code is shared with a website that can be viewed by most browsers, and hence isn’t currently able to use all the es6 features, whereas the chrome code can. This is another thing that eslint is good for enforcing.
Our eslint configuration is evolving at the moment, as we enable more rules, which we’re tracking in this bug.
Last week I gave a talk at the Philly Tech Week 2015 Dev Day organized by the delightful people at technical.ly on some of the tricks/strategies we use in the Firefox OS Gaia Email app. Note that the credit for implementing most of these techniques goes to the owner of the Email app’s front-end, James Burke. Also, a special shout-out to Vivien for the initial DOM Worker patches for the email app.
I tried to avoid having slides that both I would be reading aloud as the audience read silently, so instead of slides to share, I have the talk script. Well, I also have the slides here, but there’s not much to them. The headings below are the content of the slides, except for the one time I inline some code. Note that the live presentation must have differed slightly, because I’m sure I’m much more witty and clever in person than this script would make it seem…
Cover Slide: Who!
Hi, my name is Andrew Sutherland. I work at Mozilla on the Firefox OS Email Application. I’m here to share some strategies we used to make our HTML5 app Seem faster and sometimes actually Be faster.
What’s A Firefox OS (Screenshot Slide)
Here are some screenshots. We’ve got the default home screen app, the clock app, and of course, the email app.
It’s an entirely client-side offline email application, supporting IMAP4, POP3, and ActiveSync. The goal, like all Firefox OS apps shipped with the phone, is to give native apps on other platforms a run for their money.
And that begins with starting up fast.
Fast Startup: The Problems
But that’s frequently easier said than done. Slow-loading websites are still very much a thing.
The good news for the email application is that a slow network isn’t one of its problems. It’s pre-loaded on the phone. And even if it wasn’t, because of the security implications of the TCP Web API and the difficulty of explaining this risk to users in a way they won’t just click through, any TCP-using app needs to be a cryptographically signed zip file approved by a marketplace. So we do load directly from flash.
It adds up in the form of event loop activity and competition with other threads and processes. With the exception of Promises which get their own micro-task queue fast-lane, the web execution model is the same as all other UI event loops; events get scheduled and then executed in the same order they are scheduled. Loading data from an asynchronous API like IndexedDB means that your read result gets in line behind everything else that’s scheduled. And in the case of the bulk of shipped Firefox OS devices, we only have a single processor core so the thread and process contention do come into play.
So we try not to be a naive.
Seeming Fast at Startup: The HTML Cache
If we’re going to optimize startup, it’s good to start with what the user sees. Once an account exists for the email app, at startup we display the default account’s inbox folder.
What is the least amount of work that we can do to show that? Cache a screenshot of the Inbox. The problem with that, of course, is that a static screenshot is indistinguishable from an unresponsive application.
Local Storage: Okay in small doses
We implement this by storing the HTML in localStorage.
Important Disclaimer! LocalStorage is a bad API. It’s a bad API because it’s synchronous. You can read any value stored in it at any time, without waiting for a callback. Which means if the data is not in memory the browser needs to block its event loop or spin a nested event loop until the data has been read from disk. Browsers avoid this now by trying to preload the Entire contents of local storage for your origin into memory as soon as they know your page is being loaded. And then they keep that information, ALL of it, in memory until your page is gone.
So if you store a megabyte of data in local storage, that’s a megabyte of data that needs to be loaded in its entirety before you can use any of it, and that hangs around in scarce phone memory.
To really make the point: do not use local storage, at least not directly. Use a library like localForage that will use IndexedDB when available, and then fails over to WebSQLDatabase and local storage in that order.
Now, having sufficiently warned you of the terrible evils of local storage, I can say with a sorta-clear conscience… there are upsides in this very specific case.
The synchronous nature of the API means that once we get our turn in the event loop we can act immediately. There’s no waiting around for an IndexedDB read result to gets its turn on the event loop.
This matters because although the concept of loading is simple from a User Experience perspective, there’s no standard to back it up right now. Firefox OS’s UX desires are very straightforward. When you tap on an app, we zoom it in. Until the app is loaded we display the app’s icon in the center of the screen. Unfortunately the standards are still assuming that the content is right there in the HTML. This works well for document-based web pages or server-powered web apps where the contents of the page are baked in. They work less well for client-only web apps where the content lives in a database and has to be dynamically retrieved.
The two events that exist are:
“DOMContentLoaded” fires when the document has been fully parsed and all scripts not tagged as “async” have run. If there were stylesheets referenced prior to the script tags, the script tags will wait for the stylesheet loads.
“load” fires when the document has been fully loaded; stylesheets, images, everything.
But none of these have anything to do with the content in the page saying it’s actually done. This matters because these standards also say nothing about IndexedDB reads or the like. We tried to create a standards consensus around this, but it’s not there yet. So Firefox OS just uses the “load” event to decide an app or page has finished loading and it can stop showing your app icon. This largely avoids the dreaded “flash of unstyled content” problem, but it also means that your webpage or app needs to deal with this period of time by displaying a loading UI or just accepting a potentially awkward transient UI state.
(Trivial HTML slide)<link rel=”stylesheet” ...> <script ...></script> DOMContentLoaded!
This is the important summary of our index.html.
We reference our stylesheet first. It includes all of our styles. We never dynamically load stylesheets because that compels a style recalculation for all nodes and potentially a reflow. We would have to have an awful lot of style declarations before considering that.
Then we have our single script file. Because the stylesheet precedes the script, our script will not execute until the stylesheet has been loaded. Then our script runs and we synchronously insert our HTML from local storage. Then DOMContentLoaded can fire. At this point the layout engine has enough information to perform a style recalculation and determine what CSS-referenced image resources need to be loaded for buttons and icons, then those load, and then we’re good to be displayed as the “load” event can fire.
After that, we’re displaying an interactive-ish HTML document. You can scroll, you can press on buttons and the :active state will apply. So things seem real.
Being Fast: Lazy Loading and Optimized Layers
But now we need to try and get some logic in place as quickly as possible that will actually cash the checks that real-looking HTML UI is writing. And the key to that is only loading what you need when you need it, and trying to get it to load as quickly as possible.
There are many module loading and build optimizing tools out there, and most frameworks have a preferred or required way of handling this. We used the RequireJS family of Asynchronous Module Definition loaders, specifically the alameda loader and the r-dot-js optimizer.
One of the niceties of the loader plugin model is that we are able to express resource dependencies as well as code dependencies.
RequireJS Loader Pluginsvar fooModule = require('./foo'); var htmlString = require('text!./foo.html'); var localizedDomNode = require('tmpl!./foo.html');
The standard Common JS loader semantics used by node.js and io.js are the first one you see here. Load the module, return its exports.
But RequireJS loader plugins also allow us to do things like the second line where the exclamation point indicates that the load should occur using a loader plugin, which is itself a module that conforms to the loader plugin contract. In this case it’s saying load the file foo.html as raw text and return it as a string.
But, wait, there’s more! loader plugins can do more than that. The third example uses a loader that loads the HTML file using the ‘text’ plugin under the hood, creates an HTML document fragment, and pre-localizes it using our localization library. And this works un-optimized in a browser, no compilation step needed, but it can also be optimized.
We then also run the optimizer against our other important cards like the “compose” card and the “message reader” card. We don’t do this for all cards because it can be hard to carve up the module dependency graph for optimization without starting to run into cases of overlap where many optimized files redundantly include files loaded by other optimized files.
Plus, we have another trick up our sleeve:
Seeming Fast: Preloading
Preloading. Our cards optionally know the other cards they can load. So once we display a card, we can kick off a preload of the cards that might potentially be displayed. For example, the message list card can trigger the compose card and the message reader card, so we can trigger a preload of both of those.
But we don’t go overboard with preloading in the frontend because we still haven’t actually loaded the back-end that actually does all the emaily email stuff. The back-end is also chopped up into optimized layers along account type lines and online/offline needs, but the main optimized JS file still weighs in at something like 17 thousand lines of code with newlines retained.
So once our UI logic is loaded, it’s time to kick-off loading the back-end. And in order to avoid impacting the responsiveness of the UI both while it loads and when we’re doing steady-state processing, we run it in a DOM Worker.
Being Responsive: Workers and SharedWorkers
DOM Workers are background JS threads that lack access to the page’s DOM, communicating with their owning page via message passing with postMessage. Normal workers are owned by a single page. SharedWorkers can be accessed via multiple pages from the same document origin.
By doing this, we stay out of the way of the main thread. This is getting less important as browser engines support Asynchronous Panning & Zooming or “APZ” with hardware-accelerated composition, tile-based rendering, and all that good stuff. (Some might even call it magic.)
When Firefox OS started, we didn’t have APZ, so any main-thread logic had the serious potential to result in janky scrolling and the impossibility of rendering at 60 frames per second. It’s a lot easier to get 60 frames-per-second now, but even asynchronous pan and zoom potentially has to wait on dispatching an event to the main thread to figure out if the user’s tap is going to be consumed by app logic and preventDefault called on it. APZ does this because it needs to know whether it should start scrolling or not.
And speaking of 60 frames-per-second…
Being Fast: Virtual List Widgets
…the heart of a mail application is the message list. The expected UX is to be able to fling your way through the entire list of what the email app knows about and see the messages there, just like you would on a native app.
This is admittedly one of the areas where native apps have it easier. There are usually list widgets that explicitly have a contract that says they request data on an as-needed basis. They potentially even include data bindings so you can just point them at a data-store.
But HTML doesn’t yet have a concept of instantiate-on-demand for the DOM, although it’s being discussed by Firefox layout engine developers. For app purposes, the DOM is a scene graph. An extremely capable scene graph that can handle huge documents, but there are footguns and it’s arguably better to err on the side of fewer DOM nodes.
So what the email app does is we create a scroll-region div and explicitly size it based on the number of messages in the mail folder we’re displaying. We create and render enough message summary nodes to cover the current screen, 3 screens worth of messages in the direction we’re scrolling, and then we also retain up to 3 screens worth in the direction we scrolled from. We also pre-fetch 2 more screens worth of messages from the database. These constants were arrived at experimentally on prototype devices.
We listen to “scroll” events and issue database requests and move DOM nodes around and update them as the user scrolls. For any potentially jarring or expensive transitions such as coordinate space changes from new messages being added above the current scroll position, we wait for scrolling to stop.
Nodes are absolutely positioned within the scroll area using their ‘top’ style but translation transforms also work. We remove nodes from the DOM, then update their position and their state before re-appending them. We do this because the browser APZ logic tries to be clever and figure out how to create an efficient series of layers so that it can pre-paint as much of the DOM as possible in graphic buffers, AKA layers, that can be efficiently composited by the GPU. Its goal is that when the user is scrolling, or something is being animated, that it can just move the layers around the screen or adjust their opacity or other transforms without having to ask the layout engine to re-render portions of the DOM.
When our message elements are added to the DOM with an already-initialized absolute position, the APZ logic lumps them together as something it can paint in a single layer along with the other elements in the scrolling region. But if we start moving them around while they’re still in the DOM, the layerization logic decides that they might want to independently move around more in the future and so each message item ends up in its own layer. This slows things down. But by removing them and re-adding them it sees them as new with static positions and decides that it can lump them all together in a single layer. Really, we could just create new DOM nodes, but we produce slightly less garbage this way and in the event there’s a bug, it’s nicer to mess up with 30 DOM nodes displayed incorrectly rather than 3 million.
But as neat as the layerization stuff is to know about on its own, I really mention it to underscore 2 suggestions:
1, Use a library when possible. Getting on and staying on APZ fast-paths is not trivial, especially across browser engines. So it’s a very good idea to use a library rather than rolling your own.
2, Use developer tools. APZ is tricky to reason about and even the developers who write the Async pan & zoom logic can be surprised by what happens in complex real-world situations. And there ARE developer tools available that help you avoid needing to reason about this. Firefox OS has easy on-device developer tools that can help diagnose what’s going on or at least help tell you whether you’re making things faster or slower:
– it’s got a frames-per-second overlay; you do need to scroll like mad to get the system to want to render 60 frames-per-second, but it makes it clear what the net result is
– it has paint flashing that overlays random colors every time it paints the DOM into a layer. If the screen is flashing like a discotheque or has a lot of smeared rainbows, you know something’s wrong because the APZ logic is not able to to just reuse its layers.
– devtools can enable drawing cool colored borders around the layers APZ has created so you can see if layerization is doing something crazy
There’s also fancier and more complicated tools in Firefox and other browsers like Google Chrome to let you see what got painted, what the layer tree looks like, et cetera.
And that’s my spiel.
The source code to Gaia can be found at https://github.com/mozilla-b2g/gaia
The email app in particular can be found at https://github.com/mozilla-b2g/gaia/tree/master/apps/email
(I also asked for questions here.)
It’s that time of year again, we have a new major release of Lightning on the horizon. About every 42 weeks, Thunderbird prepares for a major release, we follow up with a matching major version. You may know these as Lightning 2.6 or 3.3.In order to avoid disappointments, we do a series of beta releases before a such major release. This is where we need you. Please help out in making Lightning 4.0 a great success.Time flies when you are preparing for releases, so we are already at Thunderbird 38.0b3 and Lightning 4.0b3. The final release will be on May 12th and there will be at least one more beta. Please download these betas and take a moment to go through all the actions you normally do on a daily basis. Create an event, accept an invitation, complete a task. You probably have your own workflow, these are of course just examples.
Here is how to get the builds. If you have found an issue, you can either leave a comment here or file a bug on bugzilla.
- Thunderbird Beta: https://www.mozilla.org/thunderbird/all-beta.html
- You can directly select the beta version for your language on this page
- Lightning Beta: https://addons.mozilla.org/thunderbird/addon/lightning/
- Scroll down to the “Developer Channel”, expand the box and click on the download button
You may wonder what is new. I’ve gone through the bugs fixed since 3.3 and found that most issues are backend fixes that won’t be very visible. We do however have a great new feature to save copies of invitations to your calendar. This helps in case you don’t care about replying to the invitation but would still like to see it in your calendar. We also have more general improvements in invitation compatibility, performance and stability and some slight visual enhancements. The full list of changes can be found on bugzilla.
Although its highly unlikely that severe problems will arise, you are encouraged to make a backup before switching to beta. If it comforts you, I am using beta builds for my production profile and I don’t recall there being a time where I lost events or had to start over.
If you have questions or have found a bug, feel free to leave a comment here.
I guess that mostly comes from the impression that the whole story is our government watching (over) us and the worst thing that can happen is incrimination. While that might threaten some things, most people do nothing that is really interesting enough for a government to go into attack mode over it (or so they believe, and very firmly so). And I even agree that most governments (including the US and EU countries) actually actively seek out what they call "terrorist activities" (even though they often stretch that term in crazy ways) and/or child abuse and similar topics that the vast majority of citizens agree are a bad thing and are not part of - and the vast majority of politicians and government workers believe they act in the best interest of their citizens when "obviously fighting that" via their different programs of privacy-undermining surveillance. That said, most people seem to be OK with their government collecting data about them as long as it's not used to incriminate them (and when that happens, it's too late to protest the practice anyhow).
A lot has been said about that since the "Snowden leaks", but I think the more obvious short-term and direct threat is in corporate surveillance, which has been swept under the rug in most discussions recently - to the joy of Facebook, Google and other major players in that area. I have also seen that when depicting some obvious scenarios resulting of that, people start to think about it much more promptly and realize the effect on their daily lives (even if those are minor issues compared to government starting a manhunt against you with terror allegations or similar).
So what I start asking is:
- Are you OK with banks determining your credit conditions based on all his comments on Facebook and his Google searches? ("Your friends say you owe them money, and that you live beyond your means, this is gonna be difficult...")
- Are you OK with insurances changing your rates based on all that data? ("Oh, so you 'like' all those videos about dangerous sports and that deafening music, and you have some quite aggressive or even violent friends - so you see why we need to go a bit higher there, right?")
- Are you OK with prices for flights or products in online stores (Amazon etc.) being different depending on what other things you have done on the web? ("So, you already planned that vacation at that location, good, so we can give you a higher air rate as you' can't back out now anyhow.")
- And, of course, envision ads in public or half-public locations being customized for whoever is in the area. ("You recently searched for engagement rings, so we'll show ads for them wherever you go." or "Hey, this is the third time today we sat down and a screen nearby shows Viagra ads." or "My dear daughter, why do we see ads for diapers everywhere we go?")
And, of course, they are true to a degree even now. Banks are already buying data from Facebook, probably including "private" messages, for determining credit scores, insurances base rates on anything they can find out about you, flight rates as well as prices for some Amazon and other web shop products vary based on what you searched before - and ads both on your screen and even on postal mail get tailored to a profile built on all kinds of your online behavior. My questions above just take all of those another step forward - but a pretty realistic one in my opinion.
I hope thinking about questions like that makes people realize they might actually want to evade some of that and in the end they actually have something to hide.
And then, of course, that a non-profit like Mozilla, which doesn't seek to maximize money, can believably be on their side and help them regain some privacy where they - now - want to.
The next major release of Thunderbird, version 38, is now in beta and available for testing. You may download Thunderbird 38.0b1 here.
This version of Thunderbird is the first that is mostly managed by volunteer community members rather than by Mozilla staff. We have many new features, including:
- Message filtering when a message is sent or archived
- File-per-message local storage available for new accounts (maildir)
- Contact search over multiple address books
- Internationalized domain names for RSS feeds
- Allow expanded columns to the folder pane for folder size and counts
Release notes are available here.
There are still a couple of features missing from this beta that we hope to ship in the final version of Thunderbird 38. Those are:
- Ship Lightning calendar addon with Thunderbird with an opt-out dialog
- Use OAUTH authentication with Gmail IMAP accounts
The primary fear, it seems, is that knowledge that the largest open-source email client was still receiving regular updates would impel its userbase to agitate for increased funding and maintenance of the client to help forestall potential threats to the open nature of email as well as to innovate in the space of providing usable and private communication channels. Such funding, however, would be an unaffordable luxury and would only distract Mozilla from its central goal of building developer productivity tooling. Persistent rumors that Mozilla would be willing to fund Thunderbird were it renamed Firefox Email were finally addressed with the comment, "such a renaming would violate our current policy that all projects be named Persona."
In the spirit of Twitter I will keep this blog post down to 140 characters. Check out @mozcalendar for more frequent updates on the project.
We’re happy to report that Thunderbird usage continues to expand.
Mozilla measures program usage by Active Daily Installations (ADI), which is the number of pings that Mozilla servers receive as installations do their daily plugin block-list update. This is not the same as the number of active users, since some users don’t access their program each day, and some installations are behind firewalls. An estimate of active monthly users is typically done by multiplying the ADI by a factor of 3.
To plot changes in Thunderbird usage over time, I’ve picked the peak ADI for each month for the last few years. Here’s the result:
Germany has long been our #1 country for usage, but in 4th quarter 2014, Japan exceeded US as the #2 country. Here’s the top 10 countries, taken from the ADI count of February 24, 2015:Rank Country ADI 2015-02-24 1 Germany 1,711,834 2 Japan 1,002,877 3 United States 927,477 4 France 777,478 5 Italy 514,771 6 Russian Federation 494,645 7 Poland 480,496 8 Spain 282,008 9 Brazil 265,820 10 United Kingdom 254,381 All Others 2,543,493 Total 9,255,280
Country Rankings for Thunderbird Usage, February 24, 2015
The Thunderbird team is now working hard preparing our next major release, which will be Thunderbird 38 in May 2015. We’ll be blogging more about that release in the next few weeks, including reporting on the many new features that we have added.
This is the first of a few posts that I’m planning regarding discussion about how we implement and work on the desktop and standalone parts of Firefox Hello. We’ve been doing some things in different ways, which we have found to be advantageous. We know other teams are interested in what we do, so its time to share!
First, a little bit of architecture: The panels and conversation window run in content processes (just like regular web pages). The conversation window shares code with the link-clicker pages that are on hello.firefox.com.
Hence those parts run very much in a web-style, and for various reasons, we decided to create them in a web-style manner. As a result, we’ve ended up with using React and Flux to aid our development.
I’ll detail more about the architecture in future posts.
The Flux Pattern
Flux is a recommended pattern for use alongside React, although I think you could use it with other frameworks as well. I’ll detail here about how we use Flux specifically for Hello. As Flux is a pattern, there’s no one set standard and the methods of implementation vary.
The main parts of a flux system are stores, components and actions. Some of this is a bit like an MVC system, but I find there’s better definition about what does what.
An action is effectively a result of an event, that changes the system. For example, in Loop, we use actions for user events, but we also use them for any data incoming from the server.
A store contains the business logic. It listens to actions, when it receives one, it does something based on the action and updates its state appropriately.
A component is a view. The view has a set of properties (passed in values) and/or state (the state is obtained from the store’s state). For a given set of properties and state, you always get the same layout. The components listen for updates to the state in the stores and update appropriately.
We also have a dispatcher. The dispatcher dispatches actions to interested stores. Only one action can be processed at any one time. If a new action comes in, then the dispatcher queues it.
Actions are always synchronous – if changes would happen due to external stimuli then these will be new actions. For example, this prevents actions from blocking other actions whilst waiting for a response from the server.
What advantages do we get?
For Hello, we find the flux pattern fits very nicely. Before, we used a traditional MVC model, however, we kept on getting in a mess with events being all over the place, and application logic being wrapped in amongst the views as well as the models.
Now, we have a much more defined structure:
- Components/views are a place for displaying, there’s some logic about what to display, but it isn’t business logic.
- The business logic exists in the stores, and is triggered by actions.
- You can follow an action through and find out which stores listen for it, and what they do.
- Actions themselves are well-defined with specified parameters.
React provides the component structure, it has defined ways of tracking state and properties, and the re-rendering on state change gives much automation. Since it encourages the separation of immutable properties, a whole class of inadvertent errors is eliminated.
There’s also many advantages with debugging – we have a flag that lets us watch all the actions going through the system, so its much easier to track what events are taking place and the data passed with them. This combined with the fact that actions have limited scope, helps with debugging the data flows.
Simple Unit Testing
For testing, we’re able to do unit testing in a much simpler fashion:
- Components/Views are tested by setting up their state and/or properties and ensuring the correct elements are displayed:
- Stores are tested by setting an initial state, sending an action, and checking the resultant state:
We therefore have many tests written at the unit test level. Many times we’ve found and prevented issues whilst writing these tests, and yet, because these are all content based, we can run the tests in a few seconds. I’ll go more into testing in a future post.
Here’s a few references to some of the areas in our code base that are good example of our flux implementation. Note that behind the scenes, everything is known as Loop – the codename for the project.
Conclusion and more coming…
We’ve found using the flux model is much more organised than we were with an MVC, possibly its just a better defined methodology, but it gave us the structure we badly missing. In future posts, I’ll discuss about our development facilities, more about the desktop architecture and whatever else comes up, so please do leave questions in the comments and I’ll try and answer them either direct or with more posts.
At the end of the last part in this series, I posed the question, "Which email security protocol is most popular?" The answer to the question is actually neither S/MIME nor PGP, but a third protocol, DKIM. I haven't brought up DKIM until now because DKIM doesn't try to secure email in the same vein as S/MIME or PGP, but I still consider it relevant to discussing email security.
Unquestionably, DKIM is the only security protocol for email that can be considered successful. There are perhaps 4 billion active email addresses . Of these, about 1-2 billion use DKIM. In contrast, S/MIME can count a few million users, and PGP at best a few hundred thousand. No other security protocols have really caught on past these three. Why did DKIM succeed where the others fail?
DKIM's success stems from its relatively narrow focus. It is nothing more than a cryptographic signature of the message body and a smattering of headers, and is itself stuck in the DKIM-Signature header. It is meant to be applied to messages only on outgoing servers and read and processed at the recipient mail server—it completely bypasses clients. That it bypasses clients allows it to solve the problem of key discovery and key management very easily (public keys are stored in DNS, which is already a key part of mail delivery), and its role in spam filtering is strong motivation to get it implemented quickly (it is 7 years old as of this writing). It's also simple: this one paragraph description is basically all you need to know .
The failure of S/MIME and PGP to see large deployment is certainly a large topic of discussion on myriads of cryptography enthusiast mailing lists, which often like to partake in propositions of new end-to-end encryption of email paradigms, such as the recent DIME proposal. Quite frankly, all of these solutions suffer broadly from at least the same 5 fundamental weaknesses, and I see it unlikely that a protocol will come about that can fix these weaknesses well enough to become successful.
The first weakness, and one I've harped about many times already, is UI. Most email security UI is abysmal and generally at best usable only by enthusiasts. At least some of this is endemic to security: while it mean seem obvious how to convey what an email signature or an encrypted email signifies, how do you convey the distinctions between sign-and-encrypt, encrypt-and-sign, or an S/MIME triple wrap? The Web of Trust model used by PGP (and many other proposals) is even worse, in that inherently requires users to do other actions out-of-band of email to work properly.
Trust is the second weakness. Consider that, for all intents and purposes, the email address is the unique identifier on the Internet. By extension, that implies that a lot of services are ultimately predicated on the notion that the ability to receive and respond to an email is a sufficient means to identify an individual. However, the entire purpose of secure email, or at least of end-to-end encryption, is subtly based on the fact that other people in fact have access to your mailbox, thus destroying the most natural ways to build trust models on the Internet. The quest for anonymity or privacy also renders untenable many other plausible ways to establish trust (e.g., phone verification or government-issued ID cards).
Key discovery is another weakness, although it's arguably the easiest one to solve. If you try to keep discovery independent of trust, the problem of key discovery is merely picking a protocol to publish and another one to find keys. Some of these already exist: PGP key servers, for example, or using DANE to publish S/MIME or PGP keys.
Key management, on the other hand, is a more troubling weakness. S/MIME, for example, basically works without issue if you have a certificate, but managing to get an S/MIME certificate is a daunting task (necessitated, in part, by its trust model—see how these issues all intertwine?). This is also where it's easy to say that webmail is an unsolvable problem, but on further reflection, I'm not sure I agree with that statement anymore. One solution is just storing the private key with the webmail provider (you're trusting them as an email client, after all), but it's also not impossible to imagine using phones or flash drives as keystores. Other key management factors are more difficult to solve: people who lose their private keys or key rollover create thorny issues. There is also the difficulty of managing user expectations: if I forget my password to most sites (even my email provider), I can usually get it reset somehow, but when a private key is lost, the user is totally and completely out of luck.
Of course, there is one glaring and almost completely insurmountable problem. Encrypted email fundamentally precludes certain features that we have come to take for granted. The lesser known is server-side search and filtration. While there exist some mechanisms to do search on encrypted text, those mechanisms rely on the fact that you can manipulate the text to change the message, destroying the integrity feature of secure email. They also tend to be fairly expensive. It's easy to just say "who needs server-side stuff?", but the contingent of people who do email on smartphones would not be happy to have to pay the transfer rates to download all the messages in their folder just to find one little email, nor the energy costs of doing it on the phone. And those who have really large folders—Fastmail has a design point of 1,000,000 in a single folder—would still prefer to not have to transfer all their mail even on desktops.
The more well-known feature that would disappear is spam filtration. Consider that 90% of all email is spam, and if you think your spam folder is too slim for that to be true, it's because your spam folder only contains messages that your email provider wasn't sure were spam. The loss of server-side spam filtering would dramatically increase the cost of spam (a 10% reduction in efficiency would double the amount of server storage, per my calculations), and client-side spam filtering is quite literally too slow  and too costly (remember smartphones? Imagine having your email take 10 times as much energy and bandwidth) to be a tenable option. And privacy or anonymity tends to be an invitation to abuse (cf. Tor and Wikipedia). Proposed solutions to the spam problem are so common that there is a checklist containing most of the objections.
When you consider all of those weaknesses, it is easy to be pessimistic about the possibility of wide deployment of powerful email security solutions. The strongest future—all email is encrypted, including metadata—is probably impossible or at least woefully impractical. That said, if you weaken some of the assumptions (say, don't desire all or most traffic to be encrypted), then solutions seem possible if difficult.
This concludes my discussion of email security, at least until things change for the better. I don't have a topic for the next part in this series picked out (this part actually concludes the set I knew I wanted to discuss when I started), although OAuth and DMARC are two topics that have been bugging me enough recently to consider writing about. They also have the unfortunate side effect of being things likely to see changes in the near future, unlike most of the topics I've discussed so far. But rest assured that I will find more difficulties in the email infrastructure to write about before long!
 All of these numbers are crude estimates and are accurate to only an order of magnitude. To justify my choices: I assume 1 email address per Internet user (this overestimates the developing world and underestimates the developed world). The largest webmail providers have given numbers that claim to be 1 billion active accounts between them, and all of them use DKIM. S/MIME is guessed by assuming that any smartcard deployment supports S/MIME, and noting that the US Department of Defense and Estonia's digital ID project are both heavy users of such smartcards. PGP is estimated from the size of the strong set and old numbers on the reachable set from the core Web of Trust.
 Ever since last April, it's become impossible to mention DKIM without referring to DMARC, as a result of Yahoo's controversial DMARC policy. A proper discussion of DMARC (and why what Yahoo did was controversial) requires explaining the mail transmission architecture and spam, however, so I'll defer that to a later post. It's also possible that changes in this space could happen within the next year.
 According to a former GMail spam employee, if it takes you as long as three minutes to calculate reputation, the spammer wins.