Question

I have some C code which writes Ruby code into Git’s post-commit hook. The way this is currently being pulled off is by embedding the Ruby code directly in a C string like so…

    char * post_commit_hook = <<Ruby code here>>

It’s then written directly to .git/hooks/post-commit by way of fprintf.

This is somewhat ugly and difficult to maintain IMO, and I was wondering if there was some way to move the Ruby code into its own file. I tried looking for ways to have GNU make to do text replacement on the fly, but somehow that still feels like a hack. Anyone have any ideas?

Answer 1

Put your code into its own file and generate a C header from that via make and a scripting language of your choice.

For example, the following make rule

hook.h : hook.rb
    ./rb2h POST_COMMIT_HOOK < $< > $@

together with this Perl script rb2h

#!perl -w
print "#define $ARGV[0] \\\n";
chomp, s/\\/\\\\/g, s/"/\\"/g, print "\t\"$_\" \\\n" for <STDIN>;
print "\t\"\"\n"

will generate a file hook.h which defines the macro POST_COMMIT_HOOK containing your code.