The whole planet here

  class Testable {
    bool ok_;
    typedef void (Testable::*bool_type)() const;
    void this_type_does_not_support_comparisons() const {}
  public:
    explicit Testable(bool b=true):ok_(b) {}

    operator bool_type() const {
      return ok_==true ?
        &Testable::this_type_does_not_support_comparisons : 0;
    }
  };

Simple, eh? Let’s examine what’s going on here. First, we typedef bool_type to be a pointer to a const member function of Testable, taking zero arguments and returning void. This is our magic type that allows for testing in Boolean contexts, without taking part in overloading contexts. Next, we define a conversion function to bool_type, just as we did with bool and void* earlier. Finally, we return “true” using a pointer to a member function (this_type_does_not_support_comparisons), which fits the bool_type, and a null value for “false”. It’s now possible to safely test instances of Testable in Boolean contexts. The strange name does have a purpose; read on to find out what it is!

Yeah, simple! the way I like it. XD

The problem is I need both root permissions on both machines, on the local machine having root permissions is the easy part but how should we proceed to get root permissions at the other end ?

You can do several things, like creating the root user, disable sudo asking for password, … but I won’t recommend them. The solution I came across ( I don’t remember from where ) is simple, but quite forgivable (that’s why I’m writing a post-to-myself). Here it is:

stty -echo; ssh myUser@REMOTE_SERVER "sudo -v"; stty echo
rsync -avze ssh --rsync-path='sudo rsync' myUser@REMOTE_SERVER:/REMOTE_PATH/ LOCAL_PATH

The second line tells sudo to execute “sudo rsync” instead of “rsync” on the remote host. Without the first line sudo will prompt for a password (and we won’t be able to input it), the “sudo -v” is the one which does the trick. It simply touches the timestamp sudo has to avoid asking the password on each call.

The “stty [-]echo” avoid others to have a look at our passwords while we type them

Complete migration from subversion to git

This is for those that want to throw subversion away completely, for some reason this is the easiest way to switch. First what you would do on the server:

# first clone the repository from subversion
# if you can use file:// it will be faster,
# otherwise use http://your-project-url.com/svn/MySuperProject
[server]$ git svn clone -s file:///home/pplux/…/svn/MySuperProject tmp
# clone to a bare new git repository (with no track of subversion)
[server]$ git clone –bare file://`pwd`/tmp MySuperProject
# remove the old git repo from subversion, no longer needed
[server]$ rm -rf tmp/
# update server info, for “dumb” servers this is needed
[server]$ cd MySuperProject/
[server]$ git –bare update-server-info


Now clients can simple clone your repository and start working:
# use this for normal-read-only, or maybe you could use ssh://
# if you plan to upload data.
[client] $ git clone http://your-server-url.com/git/MySuperProject


Mirroring the subversion repository and keep subversion

Here we want to keep the subversion repository like the main reference of the project, but let people (or ourselves) use git for development. The reason to mirror the subversion is just a matter of speed, it is much faster to clone an existing git repository than cloning from subversion each time.

Here we will need to do a bit more of work, but it’s a much smoother way to migrate from subversion to git. First what we need to do on the server:

# Create and initialize a bare git repository
[server]$ mkdir MySuperProject[server]$ cd MySuperProject/
[server]$ git –bare init
Initialized empty Git repository in /home/pplux/…/MySuperProject/


# set svn project to import
[server]$ git –bare svn init -s http://your-server-url.com/svn/MySuperProject


# fetch svn data (sloooow)
[server]$ git –bare svn fetch –all
A src/CMakeLists.txt
A CMakeLists.txt
W: +empty_dir: trunk/include
…


# auxiliary files to help “dumb” servers
[server]$ git –bare update-server-info


Now the client, here we will do much more work than before to setup both the origin from the git mirror and the subversion config to commit there future changes.

# Create and initialize our copy of the git repository
[client] $ mkdir MySuperProject
[client] $ cd MySuperProject/
[client] $ git init
Initialized empty Git repository in /Users/pplux/projects/MySuperProject/.git/


# setup the server as the initial origin of data
[client] $ git remote add origin http://your-server-url.com/git/MySuperProject


# also tell git to fecth data from the remote origin(that case svn)
[client] $ git config –add remote.origin.fetch ‘+refs/remotes/*:refs/remotes/*’


# fetch data from the git mirror(takes a bit)
[client] $ git fetch
got 2c68737541f19685f667f601a502447425d1fcfe
walk 2c68737541f19685f667f601a502447425d1fcfe
got d4916373650b9bb636c0284dd501e6c7bfa8e304
got 13af9568120f8e7771bd386d9b7dadf69f1181cb
…


# setup the original subversion as
[client] $ git svn -s init http://your-server-url.com/svn/MySuperProject


# rebuild data…
[client] $ git svn fetch
Rebuilding .git/svn/trunk/.rev_map.1a3bf6a2-ba3d-0410-9263-a3f888f14dcd …
r1 = 126490373bfbc2a770d762398b67fffeef73bead
r2 = a2288725c8c68ef426b97cf2b28a9135a34734d3
r3 = 4158b92a5c68489bb6ff2b4f4567cf8f830d7282


# to start working create a master that will track “trunk”
[client] $ git checkout -b master -t trunk


Reasons for switching to git

The post ends here you can safely stop reading now, but if you ask me, there are some good reasons to switch to git:

• it’s faster, not only faster when doing actual SCM work, it allows you to develop faster, no need to wait while the commit is transmitted to the server, you can work offline wherever you are…
• it works well with subversion, you can use it even if the main project never moves from a subversion repository or you are the only one using git while everybody else is using subversion
• you don’t need to develop a full feature before a commit, you can work on your own doing commits often without worrying about anybody else.
• git is meant to work on branches, this is a different approach from the normal subversion use, with git you are supposed to work on branches, and it’s great! I like to develop different “features” on different branches, I can switch the branch, do several things at the same time… and so on.
• you have the whole history, not just the last commit.
• it’s secure, you don’t need several people to share the same repository, git “default” model works in a different way where each person has its own public git. But, everything in git is hashed, even branches, so you can easily check if your private git has the same things as the remote git (that’s difficult to achieve with subversion)
• it’s like vim vs notepad! I like git because is fun, it can do many many things, and it’s always good to have something new to play with.
• if CVS was for dinosaurs when you started using SVN, now SVN is for the Neanderthals… so start using git!
• You don’t have to be a ruby developer to use git! git is another SCM… not the cool tool just for cool ruby developers… come on.
• Because Linus Torvalds made it:
  
• … well, maybe Linus is not a good reason to use it… I don’t fancy calling people ugly and idiot, anyway git is great.

And big thanks to slack for pointing me out git, if he says something is good stuff… believe him

Other good links about what we’ve talked here:

http://www.gnome.org/~federico/news-2008-11.html#27
http://markmcb.com/tag/workflow/
http://utsl.gen.nz/talks/git-svn/intro.html#howto-track-rebuildmeta
http://www.viget.com/extend/effectively-using-git-with-subversion/
http://techbase.kde.org/Development/Tutorials/Git#Interfacing_KDE.27s_SVN_repository_with_git-svn
http://live.gnome.org/GitForGnomeDevelopers
http://tsunanet.blogspot.com/2007/07/learning-git-svn-in-5min.html
http://blogs.gnome.org/johncarr/2008/06/21/git-mirrorgnomeorg/
http://markmcb.com/2008/09/17/migrating-a-subversion-svn-project-and-server-to-git/

That’s the thing I love most from mac: how fast is to suspend and de-suspend. But, I’ve noticed that the led which indicates when the notebook is suspended, takes quite long to start pulsing. Actually, it is not safe to move the notebook until the led starts pulsing so… why? with my old G4 mac the led started almost instantly pulsing meaning that you could safely pick the notebook up and leave. Well the reason is that apple has switched to “SafeSleep” since intel notebooks, and basically means that it will store the memory content to the hard disk just in case you run out of battery.

I can not simply run out of battery, I’m always near a plug, and it doesn’t take more than few hours until I use the notebook again… so there must be some way to use the not-so-safe-sleep-but-much-quicker. I searched a bit, and found this:

http://www.macworld.com/article/53471/2006/10/sleepmode.html
http://kimklai.blogspot.com/2007/11/hibernate-on-osx.html
http://www.radiotope.com/content/os-x-105-leopard-hibernate-options
http://installingcats.com/tag/safe-sleep/

The quick answer is you can turn off safeSleep with:

sudo pmset -a hibernatemode 0
And then take rid of the sleep image
sudo rm /var/vm/sleepimage

But there is a better way and is a little dashboard widget that does the same thing, allows you to change and perform a deep sleep on demand (deep sleep means store the memory state to the hard disk and shut down the machine completely, so no battery is used at all).

http://deepsleep.free.fr/

Disable space switching on command-tab:

That annoys me, when I’m working on a space I don’t want to be switched to another when changing the application focus. This is straightforward:
http://www.macosxhints.com/article.php?story=2008021122525348

defaults write com.apple.Dock workspaces-auto-swoosh -bool NO
killall Dock

To reset settings:

defaults delete com.apple.Dock workspaces-auto-swoosh

About Software

Good software for your mac:

• MacVim : beautiful graphical vim
• macports: Why ports and not fink? basically if you want the good stuff from fink you will end up compiling, so… why do not start from the beginning ?
• iSerialReader : … no comments …
• TED and Transmision : great for watching TV shows… in English of course (this two are platform independent, not just for mac)
• Adium: far better than iChat… and also works great with Bonjour.
• vmware fusion: … not free software, but works great to run a windows when you need it, or a Linux
• QuickSilver: No, this one is no longer needed, for me Spotlight is now better than quicksilver for just launching applications.

About the Terminal and screen

I spend most of the time working with terminal and vim, so the first I’ve done is change the colors to a much better white over black background, but most of the colors work better with a white background by default, so now the problem is how to change that. I’ve added this to the “~/.bash_profile”:

alias gvim="open -a macvim"
export SVN_EDITOR=`which vim`

alias ls="ls -G"
export LSCOLORS="gxfxcxdxbxgegdabaeacad"

if [ -f /opt/local/etc/bash_completion ]; then
	. /opt/local/etc/bash_completion
fi

if [ -f $HOME/.profile ]; then
	. $HOME/.profile
fi

alias screen='SCREEN_PWD=$(pwd) /usr/bin/screen'

case "$TERM" in
	xterm-color)
		PS1='\[\033[01;32m\]\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\] \u\$ '
		;;
	screen )
		PS1="\[\033[01;33m\]${STY%%.*}-${WINDOW}\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\] \u\$ ";
		cd "$SCREEN_PWD";
		;;
	*)
		PS1='\h:\w \u\$ '
		;;
esac

Here I’ve tweaked the color of the “ls” output to be more readable with black background, and also changed the prompt to have colors and give more info. There are some lines to make the screen command ( if you don’t know what screen is for, you’re missing a really good program here) work better, you will also need to add this to the “~/.screenrc”

startup_message off
shell -/bin/bash

When screen is launched the prompt will change, it will show in yellow something like “5867-0:/opt/local pplux$” the first number is the PID of the current screen instance, that could help you if you run more than one because writing “screen -ls” will show the list of instances identified by its PID. The number after the stroke is the window number inside screen.

And that’s all…

I’ve placed a new category English (RSS) for those that don’t care what I have to say in Spanish XD

And pleeeeeeeease, If you find any mistake in my grammar, vocabulary, etc. leave me a comment! I’m also trying to improve my English

Cómo no se va a acabar, y eso lo afirmo ya (como informático-físico-teórico que soy) pues va a ser que empezamos la temporada “vuelta al cole”, con nuevos papers por escribir, una tesis que no se si acabaremos, y un mundo nuevo de incertidumbres entre las que se encuentra que se me acaba la beca. Si alguien quiere ofrecerme trabajo, bien sea como desarrollador de videojuegos, gráficos o algo interesante o bien cobrando una pasta indecente, puede escribirme que con gusto le respondo

Hay muchas cosas nuevas que contar, papers interesantes que discutir, opengl’s casi-3.0 … pero se han acumulado tanto que mejor hacemos borrón y cuenta nueva. Por cierto, la gente se está animando a escribir en inglés, mr blat, sole, miguel, otros a los que no conozco pero sigo, Ricardo Cabello, Iñigo Quilez, Jesus de Santos Garcia, Román Cortés (no en todos),
Víctor M. Muriel, Ruben Penalva, … y otros que seguro me estoy dejando. ¿Será el momento de intentar escribir en inglés?

y también… real como la vida misma I y extraordinariamente real.