Update Homebrew and list the updated formulae.

1 files changed, 36 insertions, 0 deletions

diff --git a/Library/Homebrew/refresh_brew.rb b/Library/Homebrew/refresh_brew.rb
new file mode 100644
index 000000000..753036ed5
--- /dev/null
+++ b/Library/Homebrew/refresh_brew.rb
@@ -0,0 +1,36 @@
+class RefreshBrew
+  UPDATE_COMMAND   = 'git pull origin masterbrew'
+  REVISION_COMMAND = 'git log -l -1 --pretty=format:%H'
+  GIT_UP_TO_DATE   = 'Already up-to-date.'
+  UPDATED_FORMULA  = %r{^\s+Library/Formula/(.+?)\.rb\s}
+  
+  attr_reader :updated_formulae
+  
+  def initialize
+    @updated_formulae = []
+  end
+  
+  # Performs an update of the homebrew source. Returns +true+ if a newer
+  # version was availble, +false+ if already up-to-date.
+  def update_from_masterbrew!
+    output = git_pull!
+    output.split("\n").each do |line|
+      @updated_formulae << $1 if line =~ UPDATED_FORMULA
+    end
+    output.strip != GIT_UP_TO_DATE
+  end
+  
+  def pending_formulae_changes?
+    !@updated_formulae.empty?
+  end
+  
+  def current_revision
+    `#{REVISION_COMMAND}`.strip
+  end
+  
+  private
+  
+  def git_pull!
+    Dir.chdir(HOMEBREW_PREFIX) { `#{UPDATE_COMMAND}` }
+  end
+end
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