Saturday, December 3, 2011

Results are not enough

Of course, results are a very important part of a manager's evaluation.  But that's not the end of the story...

Consider the manager of a great team of engineers. One can expect that the team will deliver good results. And this may be the case even if the manager is not so great... Conversely, let's consider the manager of a bad team: it may be the case that whatever the manager will do, the team will not deliver. In the long run, a great manager will manage to improve the results he gets from the team, but it may take quite some time. Evaluation of the managers only from the team's results is thus not enough, and may even be completely counter-productive...

So what's a good manager to do?

Of course, a manager must make plans. But that's not enough: as Tom Foster puts it, managers should build robust plans that take external factors not under their control into account. And they should be judged on the fact that they not only planned for success, but made it more likely to happen. Luck, or the lack of it, should not play a role. Kids learning chess often setup traps, only to discover that their opponent did you fall into it. They plan for the best, instead of planning for the worst. Explicitly supposing that things can go wrong is a good way to not depend on random external factors, and improve the likelihood of getting good results.

Getting results is not the mark of a good manager.  Consistently getting results is.

Thursday, March 31, 2011

Partial working copies with Subversion

When working on large and/or multi-platform projects, it often happens that your Subversion working copy contains items that are useless: ports for other platforms, module that you don't need for your work, etc.

Recent Subversion versions allow to specify the maximum depth to use when updating a given target.  You can e.g. specify that you only want the files in a given directory, but not its sub-directories.  Or you want a given directory to be empty, or removed from the working copy entirely.

Let's consider you've checked out an entire working copy, with the following structure:


If you're not interested anymore in subdir2.1 and its content, you can issue the following commands:
> cd root/dir2
> svn update --set-depth exclude subdir2.1
Now dir2 only has file2.1, and an 'svn update' command that does not specify a '--set-depth' option will not bring back subdir2.1 or any of its content.

If you're only interested in the files inside dir1, but not the subdir1.*, you could do:
> cd root
> svn update --set-depth files dir1
This tells SVN to only get the files in dir1, but not its sub-directories

Similarly, you can use '--set-depth empty' to get an empty directory (this can be useful to ask for one of its sub-directories), '--set-depth immediates' to get the immediate sub-directories, and use '--set-depth infinity' to restore the default and get everything in a given directory.

On the reverse, if you have to checkout a working copy but you know you only need some parts of it, you can use the '--depth' option (not '--set-depth', go figure...) of the checkout command.  Then you create your paths in your working copy, step by step:
> svn checkout --depth empty [repository URL] root
> svn update --set-depth empty root/dir1
> svn update --set-depth infinity root/dir1/subdir1.2
> svn update --set-depth infinity root/dir3

Hope this helps!

Friday, March 18, 2011

New features in C++0x allow really impressive stuff...

Slack has a very interesting blog entry about Automatic memoization in C++0x...

Memoization is a pretty well-known optimization technique which consists in “remembering” (i.e.: caching) the results of previous calls to a function, so that repeated calls with the same parameters are resolved without repeating the original computation.

He starts with the short and simple Python function that returns a memoized function from any regular one, and then shows how C++0x features can be used to do the same!

Very impressive...

Wednesday, January 5, 2011

Opening the Fisheye page for your current file from your IDE

Our revision control system is SVN, with a Fisheye server providing easy browsing of the repository. I use Fisheye very much and was tired of having to dig through the deep hierarchies of our project to display the information about a file. I therefore wrote a very little script that I can launch from Visual Studio to open the Fisheye page for the current file, with the correct branch/trunk information.

This script assumes that the directory structure on the disk mimicks the directory structure on the SVN repository, with a prefix (here: f:\work): f:\work\theProject\branches\aBranch\foo.txt corresponds to file foo.txt in the root directory of project theProject on branch aBranch. This will open page https://your-fisheye-server/browse/theProject/branches/aBranch/foo.txt. Of course, you will probably want to edit the location of the server...

rem Launch a browser directed to the Fisheye page for
rem a particular file.

@echo off

rem Assumption: first argument is a absolute path to the file
rem on the disk for which we would like to display the
rem corresponding Fisheye page.
set FILE=%1

rem Remove the "f:\work" prefix from the file path
set FILE=%FILE:f:\work=%
rem @echo %FILE%

rem Replace all the backslashes with forward slashes
set FILE=%FILE:\=/%
rem @echo %FILE%

start "c:\Program Files\Mozilla Firefox 4\firefox.exe" https://your-fisheye-server/browse%FILE%

You will have to launch this script from your IDE with as single argument the full path to the file you want to see in Fisheye. Here is how to do this from Visual Studio. Open the 'Tools' -> 'External tools...' menu, click the 'Add' button, and fill the information needed, using $(ItemPath) for the argument:
You now have a 'Current file on Fisheye' entry on your Tools menu, that you simply have to choose to launch Firefox...

I hope you'll find this useful...