Gordon P. Hemsley

Linguist by day. Web developer by night.

Posts Tagged ‘bug’

PHP, MySQL, and the BIT field type

Posted by Gordon P. Hemsley on February 8, 2010

As Dave Humphrey once taught me:

When you do a search, and it comes back with no results, it’s a sign that you need to write something.

This is an issue that I came across while testing SASHA (which is available for you to try out, by the way), and I didn’t know if it was a bug or a feature. I could find no mention of it anywhere, and the people in the #mysql IRC channel on FreeNode weren’t especially helpful in helping me get to the bottom of it.

What is the issue, you ask? Well, even that in and of itself is a question, because I don’t know whether it’s a bug (or feature) in PHP or MySQL. However, I’m inclined to think it’s the latter, and I’ll get to why in a moment.

But first, some background. The table that SASHA uses to store schedules uses the BIT field type for keeping track of which days of the week a schedule occurs on. I figured it’d be easiest to use a 7-bit field and just flip a bit for each day of the week. And that worked fine for me on my local test server. But then I had a colleague test SASHA out on his test server, and things went a little wacky.

It took a little while to figure out what was causing our problem, and we finally got to the bottom of it: I was using MySQL 5.0 and he was using MySQL 5.1! Apparently, between 5.0 and 5.1, the return format of a BIT field changed from the literal binary data (output in the browser as a character, because the browser didn’t know it wasn’t) to a decimal representation of that data.

The first problem with that was that I had no idea there was a possibility of getting anything but the raw binary data I was getting on my server. The second problem was coming up with a straight-forward solution to detecting whether the database was feeding us raw binary data or converted decimal data. There was no direct way to do this, but I figured out the next best thing. A simple way to check what kind of data we’re getting is to find out whether it converts cleanly to an actual character. Here’s an excerpt from SASHA that demonstrates:

// MySQL 5.0 returns bit as binary, while MySQL 5.1 returns decimal
if( $days == chr( ord( $days ) ) )
{
	$input = 'binary';
}
else
{
	$input = 'decimal';
}

That seems to do the trick when it comes to handling unpredictable BIT field data.

(Again, I can’t guarantee that this isn’t actually a PHP issue, but I seem to recall us both being around the same version of PHP.)

If you have any insight into the matter, please do leave a comment.

Advertisements

Posted in Mozilla, Open Source, SourceForge | Tagged: , , , , , , , , , , , , , , , | 4 Comments »

SVN Support in Bespin

Posted by Gordon P. Hemsley on August 10, 2009

A couple of weeks ago, I kicked off the addition of SVN support to Bespin (bug 493038). This required two things: One was the actual ability to choose which VCS you’re using, as it defaulted to Hg and the auto-detection was primitive and long since functional. (There were rumors that it had even been missing from the code for a while already.) But that was the relatively easy part, as it was mostly just manipulating HTML.

The (relatively) harder part was writing the code that would do the actual work with SVN. (VCS support in Bespin is powered by UVC.) A factor in this difficulty was that the backend code is written in Python, which I’m not especially familiar with. Nevertheless, the process was actually simplified by the way things are set up, because I was able to copy the Hg code and just modify to fit the SVN commands. I was able to add basic checkout, commit, and update support, as well as username/password authentication. Kevin later came in and finished up the push/commit differentiation, among other things. I believe SSH support still needs to be done, but we’re looking for a method to use to do it. (Kevin has suggested using environmental variables, as SVN does not have the ability to pass SSH details via command line, like Hg does.)

Kevin and the other Bespin folks are in the process of getting the 0.4.0 release out the door today or in the next couple of days, and that will include this support for SVN, as well as collaboration.

Posted in Mozilla, Open Source | Tagged: , , , , , , , , , , , , , , , , | 1 Comment »

Quick Bespin Update

Posted by Gordon P. Hemsley on April 13, 2009

A lot has happened since I last blogged about adding real tab support to Bespin. Since then, my code was merged into the main repository and things have taken off. I later tore apart a huge chunk of Bugzilla by way of sorting through and updating a lot of the old bugs, many of which had been on the books since before Bespin went public, or had been fixed a long time ago. I still have not sorted through all of them, and there are probably still a number of open bugs that fall into that latter category.

Since appointing myself the de facto Issue Manager (hat tip to amotsjonov for the link), I have been watching the incoming bugs like a hawk, and have determined that using the whiteboard to organize bugs has already become too unwieldy. Bespin needs to pop itself out of the Mozilla Labs product so that it can have components of its own. So I’ve filed a bug to that effect. I hope it will get approved and put in place soon, so that I can really attack all of the remaining unloved bugs and narrow down the focus of what there is to do.

Last week was also the first Bespin Status Meeting. After some technical difficulties getting our more foreign correspondents into the call, it went well. We discussed the near and far future of Bespin and what we plan to do. April is dogfood month, so we’re going to have to sort out the most glaring bugs and get the most important features implemented. That way, we’ll be able to use Bespin to edit Bespin. I’m looking forward to it.

Our next meeting is tomorrow. Though the agenda is not quite set yet, I do hope to discuss how things are running, and how to get them running even more smoothly. Perhaps I will chime back in after the meeting with more details.

Posted in Mozilla | Tagged: , , , , , , , , , , , , , , , , | 2 Comments »

Real Tab Support in Bespin, Part 2

Posted by Gordon P. Hemsley on March 21, 2009

A couple of days ago, I blogged about trying to add real tab support into Bespin, and about the discussion going on about where that code should live. However, I can now report that, not only have I been successful in my endeavors (again, if you count my first attempt), I have been able to accomplish it solely within the Cursor Manager. This means that I have gone against what I had originally argued for, and I did it by simply starting over.

My first few attempts helped me get familiar with the code that controls the model, the cursor, and the editor. (MVC, as Ben referred to it. But no, not that MVC.) But attempting to switch between model-awareness and cursor-awareness just cluttered up my code and confused the heck out of me. So I saved everything I had in a little patch file, then reverted all my changes and began anew. (Having Ben first commit some basic cleanup stuff I came across certainly helped to clear things, too.)

So I approached the problem logically, with none of the conceptions from my prior attempts, other than my new-found familiarity with the code. This allowed me to focus on the one task that I had: keep everything in cursor. It also helped prevent me from having dozens of search windows up trying to figure out where things were. And, after a bit of minor confusion about object state persistence and object cloning (thanks, kdangoor!), it was done pretty quickly. But it does require that any position coordinates that are sent to the model be translated via the new getModelPosition().

Since Julian Viereck has been “messing around” with “my” code a lot lately, and since this darn task has taken up a good chunk of my day every day this past week and a half, I decided to put up my own public clone of the Bespin repository on BitBucket to keep things running smoothly. That way I can mess around with things, too, and not get in other people’s way (as much). My code for the tab support is available in this changeset, in addition to this attachment on the bug.

So go merge or import or whatever it is you do in Hg, and give my code a whirl. If you find anything amiss, don’t hesitate to let me know. I would imagine Ben will be critiquing my code at some point soon and then eventually getting it into the main source. Enjoy!

Posted in Mozilla, Open Source | Tagged: , , , , , , , , , , , , , , , , , , , | 1 Comment »

Real Tab Support in Bespin

Posted by Gordon P. Hemsley on March 18, 2009

Over the past week, I have been attempting to add real tab support to Bespin (bug 474055), under the guidance of Ben Galbraith (bgalbraith). Discussion on this issue has ensued in many places, including on Ben’s blog (in which he indirectly called me a weird hippie), as well as in at least two topics on the Google Group/mailing list Bespin Core.

The issue behind supporting real tabs is getting the editor to know that a tab is a variable width character. I was able to solve the problem of calculating just how wide that character is supposed to be, but that turned out to be the easy part. The problem that I’ve/we’ve been having is whether to contain all that knowledge in the cursor code (since it is essentially only a display issue) or to allow it to seep into the model code (which does all the actual text manipulation). That discussion is still ongoing right now, but either way, the change would require a little bit of refactoring of a lot of different functions, so that we can keep track of whether the function is getting the cursor position or the model position (as the latter is really just the nth index in the array, with all characters being equal).

So that’s where I’m at now. I’ve tagged the bug with the “student-project” keyword, since I’m a student and I’m working on the project, and I’ve posted a couple of patches in the bug to track my progress (the first one actually works, for the most part; the second one, not so much). All suggestions welcome.

Posted in Mozilla | Tagged: , , , , , , , , , , , , , , | 1 Comment »