From 663ea030fc8a93ae66e6fbf148d7af88eec7c6cf Mon Sep 17 00:00:00 2001
From: Adam Vandenberg <flangy@gmail.com>
Date: Wed, 17 Mar 2010 16:56:06 -0700
Subject: [PATCH] Allow :using on head to specify a download strategy.

A 'head' in a formula can now specify which download strategy to use via
a ':using' specification:

    head 'http://svn.macosforge.org/repository/darwinbuild/trunk/',
        :using => :svn

This reduces the number of cases where "download_strategy" needs to be
overriden.
---
 Library/Homebrew/formula.rb | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 1bb4889d17..2bba3d4e7f 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -134,6 +134,23 @@ class Formula
   
   # reimplement if we don't autodetect the download strategy you require
   def download_strategy
+    vcs = @specs.delete :using
+    if vcs != nil
+      # If a class is passed, assume it is a download strategy
+      return vcs if vcs.kind_of? Class
+
+      case vcs
+      when :bzr then return BazaarDownloadStrategy
+      when :curl then return CurlDownloadStrategy
+      when :cvs then return CVSDownloadStrategy
+      when :git then return GitDownloadStrategy
+      when :hg then return MercurialDownloadStrategy
+      when :svn then return SubversionDownloadStrategy
+      end
+
+      raise "Unknown strategy #{vcs} was requested."
+    end
+
     detect_download_strategy url
   end