I also spent some time working on font enumeration performance because of an early showstopper where sites that loaded WOFF fonts spun and spun and spun. After several days of tearing my hair out in clumps the problem turned out to be a glitch in reference counting caused by the unusual way we load platform fonts: since Firefox went 10.6+ it uses CoreText exclusively, but we use almost completely different font code based on the old Apple Type Services which is the only workable choice on 10.4 and the most stable choice on 10.5. ATS is not very fast at instantiating lots of fonts, to say the least, so I made the user font cache stickier (please don't read that as "leaky" -- it's sticky because things do get cleaned up, but less aggressively to improve cache hit percentage) and also made a global font cache where the font's attribute tag directory is cached browser-wide to speed up loading font tables from local fonts on your hard disk. Previously this directory was cached per font entry, meaning if the font entry was purged for re-enumeration it had to be loaded all over again, which usually happened when the browser was hunting for a font with a particular character. This process used to take about fifteen to twenty seconds for the 700+ font faces on my G5. With the global font cache it now takes less than two.
Speaking of showstoppers, here's an interesting one which I'll note here for posterity. nsChildView, the underlying system view which connects Cocoa/Carbon to Gecko, implements the NSTextInput protocol which allows it to accept Unicode input without (as much) mucking about with the Carbon Text Services Manager (Firefox also implements NSTextInputClient, which is the new superset protocol, but this doesn't exist in 10.4). To accept Unicode input, under the hood the operating system actually manipulates a special undocumented TSM input context called, surprisingly, NSTSMInputContext (both this and the undocumented NSInputContext became the documented NSTextInputContext in 10.6), and it gets this object from a previously undocumented method on NSView called (surprise again) inputContext. Well, turns out if you override this method you can potentially cause all sorts of problems, and Mozilla had done just that to handle complex text input for plugins. Under the 10.4 SDK, however, their code ended up returning a null input context and Unicode input didn't work, so since we don't support plugins anyhow the solution was just to remove it completely ... which took several days more to figure out. The moral of the story is, if you have an NSView that is not responding to setMarkedText or other text input protocol methods, make sure you haven't overridden inputContext or screwed it up somehow.
I also did some trivial tuning to the libffi glue library to improve the speed of its calls and force it to obey our compiler settings (there was a moment of panic when the 7450 build did not start on the test machines because dyld said XUL was a 970 binary -- libffi had seen it was being built on a G5 and "helpfully" compiled it for that target), backed out some portions of browser chrome that were converted to CoreUI (not supported on 10.4), and patched out the new tab tile page entirely; all new tabs are now blank, like they used to be in previous versions of Firefox and as intended by God Himself. There are also the usual cross-platform HTML5 and CSS improvements you get when we leap from ESR to ESR like this, and graphics are now composited off-main-thread to improve display performance on multiprocessor systems.
That concludes most of the back office stuff. What about user facing improvements? Well, besides the new blank tabs "feature," we have built-in PDF viewing as promised (I think you'll find this more useful to preview documents and load them into a quicker viewer to actually read them, but it's still very convenient) and Reader View as the biggest changes. Reader View, when the browser believes it can attempt it, appears in the address bar as a little book icon. Click on it and the page will render in a simplified view like you would get from a tool such as Readability, cutting out much of the extraneous formatting. This is a real godsend on slower computers, lemme tell ya! Click the icon again to go back. Certain pages don't work with this, but many will. I have also dragged forward my MP3 decoder support, but see below first, and we have prospectively landed Mozilla bug 1151345 to fix an issue with the application menu (modified for the 10.4 SDK).
You will also note the new, in-content preferences (i.e., preferences appears in a browser tab now instead of a window, a la, natch, Chrome), and that the default search engine is now Yahoo!. I have not made this default to anything else since we can still do our part this way to support MoCo (but you can change it from the preferences, of course).
I am not aware of any remaining showstopper bugs, so therefore I'm going ahead with the beta. However, there are some known issues ("bugs" or "features" mayhaps?) which are not critical. None of these will hold up final release currently, but for your information, here they are:
- If you turn on the title bar, private browsing windows have the traffic light buttons in the wrong position. They work; they just look weird. This is somewhat different than issue 247 and probably has a separate, though possibly related, underlying cause. Since this is purely cosmetic and does not occur in the browser's default configuration, we can ship with this bug present but I'll still try to fix it since it's fugly (plus, I personally usually have the title bar on).
- MP3 support is still not enabled by default because seeking within a track (except to the beginning) does not work yet. This is the last thing to do to get this support off the ground. If you want to play with it in its current state, however, set tenfourfox.mp3.enabled to true (you will need to create this pref). If I don't get this done by 38.0.2, the pref will stay off until I do, but the rest of it is working already and I have a good idea how to get this last piece functional.
- I'm not sure whether to call this a bug or a feature, but scaling now uses a quick and dirty algorithm for many images and some non-.ico favicons apparently because we don't have Skia support. It's definitely lower quality, but it has a lot less latency. Images displayed by themselves still use the high-quality built-in scaler which is not really amenable to the other uses that I can tell. Your call on which is better, though I'm not sure I know how to go back the old method or if it's even possible anymore.
- To reduce memory pressure, 31 had closed tab and window undos substantially reduced. I have not done that yet for 38 -- near as I can determine, the more efficient memory management means it is no longer worth it, so we're back to the default 10 and 3. See what you think.
Localizers: strings are frozen, so start your language pack engines one more time in issue 42. We'd like to get the same language set for 38 that we had for 31, and your help makes it possible. Thank you!
As I mentioned before, it's probably 70-30 against there being a source parity version after 38ESR because of the looming threat of Electrolysis, which will not work as-is on 10.4 and is not likely to perform well or even correctly on our older systems. (If Firefox 45, the next scheduled ESR, still allows single process operation then there's a better chance. We still need to get a new toolchain up and a few other things, though, so it won't be a trivial undertaking.) But I'm pleased with 38 so far and if we must go it means we go out on a high note, and nothing says we can't keep improving the browser ourselves separate from Mozilla after we split apart (feature parity). Remember, that's exactly what Classilla does, except that we're much more advanced than Classilla will ever be, and in fact Pale Moon recently announced they're doing the same thing. So if 38 turns out to be our swan song as a full-blooded Mozilla tier 3 port, that doesn't mean it's the end of TenFourFox as a browser. I promise! Meanwhile, let's celebrate another year of updates! PowerPC forever!
Finally, looking around the Power Mac enthusiast world, it appears that SeaMonkeyPPC has breathed its last -- there have been no updates in over a year. We will pour one out for them. On the other hand, Leopard Webkit continues with regular updates from Tobias, and our friendly builder in the land of the Rising Sun has been keeping up with Tenfourbird. We have the utmost confidence that there will be a Tenfourbird 38 in your hands soon as well.
Some new toys to play with are next up in a couple days.