Allow formulae to use __END__

For this to work the "running script" must be the formulae file. Making this
so wasn't so hard, there is now an install.rb script which is included with
the -r flag to the ruby executable. An at_exit handler calls the install
function.

Having the install logic in its own file made it feel like there was so much
space that I added extra error handling. So there is something to be said for
separating functionality out into its own files.

Still the error handling sucks, we'll need to marshall the exception back to
the bin/brew command. Which is another PITA.

Still overall I think this will prove worthwhile. But if it doesn't we'll
revert.

As a first usage, you can put a diff after __END__ and return DATA from
Formula::patches to make Homebrew aware of it.

1 files changed, 9 insertions, 55 deletions

diff --git a/bin/brew b/bin/brew
index ba7080290..bd57b7103 100755
--- a/bin/brew
+++ b/bin/brew
@@ -1,26 +1,10 @@
 #!/usr/bin/ruby
 # -*- coding: utf-8 -*-
-$:.unshift ENV['RUBYLIB']=File.expand_path(__FILE__+'/../../Library/Homebrew')
-require 'pathname+yeast'
-require 'ARGV+yeast'
-require 'utils'
-require 'hardware'
+ENV['RUBYLIB']=HOMEBREW_RUBYLIB=File.expand_path(__FILE__+'/../../Library/Homebrew')
+$:.unshift HOMEBREW_RUBYLIB
+require 'global'
 require 'brew.h'
 
-if Process.uid == 0
-  # technically this is not the correct place, this cache is for *all users*
-  # so in that case, maybe we should always use it, root or not?
-  HOMEBREW_CACHE=Pathname.new("/Library/Caches/Homebrew")
-else
-  HOMEBREW_CACHE=Pathname.new("~/Library/Caches/Homebrew").expand_path
-end
-
-HOMEBREW_PREFIX=(Pathname.getwd+__FILE__).dirname.parent.cleanpath
-HOMEBREW_CELLAR=HOMEBREW_PREFIX+'Cellar'
-HOMEBREW_VERSION='0.4'
-HOMEBREW_WWW='http://bit.ly/Homebrew'
-HOMEBREW_USER_AGENT="Homebrew #{HOMEBREW_VERSION} (Ruby #{VERSION}; Mac OS X 10.5 Leopard)"
-
 if %w[/ /usr].include? HOMEBREW_PREFIX.to_s then abort <<-EOS
   You have placed Homebrew at the prefix: #{HOMEBREW_PREFIX}
   This is not currently supported. Voice your support for this feature at:
@@ -109,11 +93,14 @@ begin
             next
           end
 
-          # we need to ensure a pristine ENV for each process or the formula
-          # will start with the ENV from the previous build
+          # 1. formulae can modify ENV, so we must ensure that each
+          #    installation has a pristine ENV when it starts, forking now is 
+          #    the easiest way to do this
+          # 2. formulae have access to __END__ the only way to allow this is
+          #    to make the formula script the executed script
           pid=fork
           if pid.nil?
-            exec __FILE__, "install-just-one", f.name, *ARGV.options
+            exec 'ruby', '-r', "#{HOMEBREW_RUBYLIB}/install", f.path, '--', *ARGV.options
           else
             Process.wait pid
           end
@@ -122,39 +109,6 @@ begin
         end
       end
 
-    # this is an internal option, don't expose it to the user
-    when 'install-just-one'
-      require 'keg'
-
-      f=ARGV.formulae.shift
-
-      begin
-        build_time=install f
-        ohai "Caveats", f.caveats, ''
-        ohai 'Finishing up' if ARGV.verbose?
-        clean f
-        raise "Nothing was installed to #{f.prefix}" unless f.installed?
-      rescue Exception
-        if f.prefix.directory?
-          f.prefix.rmtree
-          f.prefix.parent.rmdir_if_possible
-        end
-        raise
-      end
-
-      begin
-        Keg.new(f.prefix).link
-      rescue Exception
-        onoe "The linking step did not complete successfully"
-        puts "The package built, but is not symlinked into #{HOMEBREW_PREFIX}"
-        puts "You can try again using `brew link #{f.name}'"
-        ohai "Summary" unless ARGV.verbose?
-      end
-
-      ohai "Summary" if ARGV.verbose?
-      print "#{f.prefix}: #{f.prefix.abv}"
-      print ", built in #{pretty_duration build_time}" if build_time
-      puts
 
     when 'ln', 'link'
       ARGV.kegs.each {|keg| puts "#{keg.link} links created for #{keg}"}