Rewrite of HOMEBREW_ folder locations

This rewrite attempts to sort out where the Prefix, Cellar, and
Repository are relative to the real and symlinked 'brew' command.

Also included is a --config option which dumps all of these variables.

Any top-level script must define a "BREW_FILE" that gives the path
to brew as it exists in the path. 'brew' itself just uses __FILE__ and
install.rb does a `which brew` (there may be a better way?)

The Prefix is always relative to the location of brew as it exists in
the path. Thus, whether or not /usr/local/bin/brew is a symlink or real
file, the Prefix is always /usr/local. If you have brew in some other
prefix, such as /nonstandard/bin/brew, then '/nonstandard/ will be
managed by brew instead.

The Repository, Cellar, and "Library/Homebrew" required code is always
found relative to the "real" path or brew. If brew is a real file in
/usr/local/bin/brew, then everything else will be found in /usr/local
and we'll expect a /usr/local/.git

Otherwise, we dereference brew's symlink and look for everything else
relative to that path instead.

2 files changed, 8 insertions, 8 deletions

diff --git a/Library/Homebrew/global.rb b/Library/Homebrew/global.rb
index 757fb8d74..07c5f315c 100644
--- a/Library/Homebrew/global.rb
+++ b/Library/Homebrew/global.rb
@@ -28,6 +28,8 @@ require 'hardware'
 
 ARGV.extend(HomebrewArgvExtension)
 
+HOMEBREW_VERSION = 0.4
+HOMEBREW_WWW = 'http://bit.ly/Homebrew'
 
 if Process.uid == 0
   # technically this is not the correct place, this cache is for *all users*
@@ -37,14 +39,9 @@ else
   HOMEBREW_CACHE=Pathname.new("~/Library/Caches/Homebrew").expand_path
 end
 
-HOMEBREW_PREFIX = (Pathname.getwd+__FILE__).dirname.parent.parent.cleanpath
-HOMEBREW_CELLAR = HOMEBREW_PREFIX+'Cellar'
-HOMEBREW_VERSION = 0.4
-HOMEBREW_WWW = 'http://bit.ly/Homebrew'
-
-# we use Library as we allow people to symlink their Homebrew into another
-# directory so they can hack in one place and use it in another
-HOMEBREW_REPOSITORY = (HOMEBREW_PREFIX+'Library').realpath.parent
+HOMEBREW_PREFIX = Pathname.new(BREW_FILE).dirname.parent # Where we link under
+HOMEBREW_REPOSITORY = Pathname.new(BREW_FILE).realpath.dirname.parent # Where .git is found
+HOMEBREW_CELLAR = HOMEBREW_REPOSITORY+'Cellar' # Where we build into
 
 MACOS_FULL_VERSION = `/usr/bin/sw_vers -productVersion`.chomp
 MACOS_VERSION = /(10\.\d+)(\.\d+)?/.match(MACOS_FULL_VERSION).captures.first.to_f
diff --git a/Library/Homebrew/install.rb b/Library/Homebrew/install.rb
index 927e976bc..a27cd2e4f 100755
--- a/Library/Homebrew/install.rb
+++ b/Library/Homebrew/install.rb
@@ -1,4 +1,6 @@
 #!/usr/bin/ruby
+BREW_FILE = `which brew`.strip
+
 require 'global'
 
 require 'brew.h'
@@ -8,6 +10,7 @@ require 'formula'
 require 'hardware'
 require 'keg'
 
+
 show_summary_heading = false
 
 def text_for_keg_only_formula f