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The one thing that's worse about Git compared to Subversion is that git-blame is so much harder to use than svn blame. The output from git-blame is very wide so if you run it on the terminal then often most of the line of source code will be cropped off the right edge. SVN's revision numbers are replaced with a git commit hash so it's also not immediatly obvious what the parent of a commit is from the information in git-blame. When I use either blame command, I often find the commit reported against a given line is not the change that I'm interested in so I usually want to re-run the annotation with the parent commit.

I thought it might be fun to knock up a program to browse the output of git-blame. I initially thought 'oh that's easy, that'll take about half an hour' so I cobbled together a quick program in Ruby with the GTK bindings. It was pretty quick to write because Ruby (like Perl) has excellent support for processing text. However I eventually got fed up with the Ruby GTK bindings because they are randomly missing bindings for some functions that I wanted and it's difficult to debug. After discovering this bug I got fed up and rewrote it in C. I also ended up making it much more complicated because now it tries to run git asynchronously and process the output as it comes using the glib main-loop.

So far you can see the source code for the file you've annotated with the hash of the commit for the that line. A tooltip is displayed for the commit with a short summary. If you click on the commit you get more information in a dialog and you can jump to the parent commit from there.

The screenshot gives away that I stole a function from ebassi's Tweet and also that I fixed a tiny bug in it :)

There's quite a lot left to do:

• I would like to add forward and back buttons to the main window so that you can move through the history of what you have visited.
• Searching the source and jumping to a line number are probably pretty essential.
• It should probably use GtkSourceView instead of my crazy custom widget.
• The UI looks nasty

I also should probably have tried to implement within the giggle source code but I didn't look at this until I'd got too far. It looks like giggle already has a lot of code to handle running git asynchrously so I could've avoided a lot of work.

The code is available on Github at http://github.com/bpeel/blame-browse