There are good ligatures and bad ligatures, but the “fi†ligature in Geneva is especially bad. This screenshot of Charlie Savage's blog shows Firefox trunk (which supports ligatures) on top and Safari 3 (which does not support ligatures) on the bottom. That thing looks more like a tortured “h†than an “f†followed by an “iâ€, and it makes it look like the blog's title has only three letters.
Brian Krebs recently posted a blog entry, Hiding In Plain Sight, about the continuing problem of executable files disguised as other types of files. Brian explains how to make file extensions visible on Windows XP and wonders why Microsoft didn't make that the default.
But hiding the extension by default is only part of the problem. Most users can't be expected to memorize the meanings of dozens of three-letter filename extensions. Even advanced users can't be expected to check the extension every time they download a 15-second video clip.
The real problem is that the same action -- double-clicking on a downloaded file -- has a completely different meaning depending on whether the file is a document or a program. In the first case, it means "view this document"; in the second case, it means "grant this program all of my privileges".
Mac OS X 10.5 "Leopard" tries an interesting solution: "quarantining" just-downloaded programs. If you download a program using Safari or Firefox, you get a concise dialog reminding you that it was downloaded from the Internet.
Unfortunately, Apple botched an important part of this dialog: the button label. The OS X HIG suggest that button names should be verbs that describe the action performed, so if users only read one word in the dialog, it will be one that differentiates one action from another. (Windows, in contrast, is notorious for using "Yes" and "No" as button labels.) Apple chose the verb "Open", which suffers from exactly the same problem as double-clicking: it has a vastly different meaning for documents and applications!
There is concern that because the dialog is "in the way of what you were doing", many users will click through no matter what the dialog says. So perhaps a better solution is to take a hint from the Web application security model, and grant fewer privileges to most local applications. Why should running a screen saver or local game be so much more dangerous than visiting a web page?
A third possible solution is to make the action to launch an application explicit. In a command-line setting, this action might be "chmod +x". On Mac, a natural choice would be dragging the application to the Applications folder, since that is already a normal part of installing an application.
For now, my workaround is to drag files to VLC (as a habit) instead of double-clicking them. I suggested this in the "Handling downloaded files" section of Security tips for Firefox users.
Last night, while I was trying to fall asleep, it occurred to me that religious days of rest might seem arbitrary to people living near the International Date Line. I got up and searched Google for "international date line" sabbath, thinking I might at least come across someone else who had also wondered about the same thing. What I didn't expect to find was multiple pages arguing that the International Date Line is a tool of Satan. I also found a lengthy rebuttal. Who knew that datekeeping could be so controversial?
Could this be turned into a game? Perhaps one player picks a seemingly uncontroversial object or concept, and another player must invent a story or argument that makes it out to be either the root of all evil or mankind's salvation. For example:
PODASIP: Spoons are corrupting and should be eradicated.
At WWDC in June, Steve Jobs made fun of Vista's pricing and said that there would only be one version of Leopard, at $129. But now we're finding out that only Mac OS X Server may be run virtualized. Since there are plenty of reasons to use virtualization other than for running servers, does this mean that Mac OS X Server is slowly turning into Mac OS X Ultimate?
Slashdot was largely responsible for my initial involvement in the Mozilla project, so I'm looking forward to the Slashdot anniversary party in Palo Alto tonight. Are any other Mozilla people going?
Google suggests holding tomorrow's leak meeting on a cruise ship.
Somehow I don't think that would work very well. Leaks and ships don't get along perfectly.
I turned on trace-refcnt a few days ago in order to find leak bugs. I found three yesterday and three today.
Four of the six bugs already have patches :)
Many Mozilla community members, including both volunteers and Mozilla Corporation employees, have been helping to reduce Firefox's memory usage and fix memory leak bugs lately. Hopefully, the result of this effort will be that Firefox 3 uses less memory than Firefox 2 did, especially after it has been used for several hours.
Federico Mena-Quintero submitted a patch to make Firefox discard decompressed image data after five seconds (bug 296818). ImageLib module owner Stuart Parmenter experimented with a competing idea in bug 386377, but now he plans to help with Federico's patch. The patch will make image data join text runs in using time-based caching rather than traditional space-bounded caching.
Aaron suggested having an "about:memory" page showing a breakdown of Firefox's memory use (bug 392351). When I pointed out the bug to Brendan Eich, he excitedly assigned the bug to himself.
Eli Friedman discovered that nsFloatCache was no longer necessary and eliminated most of it (bug 381385).
David Baron checked in a patch for the last bug that contributed to RLk on Linux, bringing the number of XPCOM objects leaked during this test to zero. Since this test runs on Tinderbox, it's likely that regressions will be noticed quickly, even if they don't turn Tinderbox orange.
Robert Sayre created a script to load random pages and see whether they cause leaks. The random URLs come from the Yahoo directory (biased toward older, top-level pages), del.icio.us (biased toward newer, geeky pages), and AltaVista (biased toward pornography). The script detects leaks using trace-refcnt, the same test used by RL; future versions might use trace-malloc in order to catch additional leaks. Robert has caught at least 6 distinct leak bugs using this script, 3 of which have already been fixed. See LeakingPages and bug 394517 for details.
David Baron created a series of patches to the cycle collector to aid in debugging leaks. With this code, DEBUG_CC builds of Firefox can notice when an object "expected to be garbage" is not collected and then explain in detail why it was not collected.
Steve England tested the top 500 web sites, finding two leaks. Later, he tested the top 20 Firefox extensions and found leaks in several of them.
David Baron recorded seven leak debugging screencasts, which you can watch to see how David Baron debugs real leaks.
Kris Zyp found a leak in the JavaScript Engine when using the watch method (bug 394709). Igor Bukanov responded quickly with not only a patch for the bug but also a leak detection patch to enable regression testing of JavaScript Engine leaks. I asked him to modify his patch so I could use jsfunfuzz to test for JavaScript Engine leaks, and he did. (This led me to find several bugs in evalcx, but no additional leaks.)
David Baron got the stack walking code and the stack fixer working on Mac, making it possible to use trace-malloc and the refcount balancer on Mac (bug 336517, bug 392118).
You don't have to be a C++ programmer to help find leaks in Firefox.
If you're a Firefox user, an easy way to help is to browse with a trunk nightly build wrapped in a script that calls leak-gauge.pl when Firefox exits. If it reports that documents or windows leaked, try to figure out how to reproduce the leak and then file a bug report.
If you're an advanced user, you can do something similar with with trace-refcnt, which detects leaks of all reference-counted objects, not just windows and documents. Build Firefox with the .mozconfig option "--enable-logrefcnt" (or build debug) and run your build with XPCOM_MEM_LEAK_LOG=2. When Firefox exits, it will print a detailed but understandable summary of what types of objects leaked.
If you're are a C++ programmer and want to help diagnose or fix bugs, check out Performance:Leak_Tools along with David Baron's screencasts, and hang out in #developers on irc.mozilla.org.
