1 files changed, 159 insertions, 0 deletions
diff --git a/Library/Homebrew/cmd/update.rb b/Library/Homebrew/cmd/update.rb
new file mode 100644
index 000000000..32f144c8e
--- /dev/null
+++ b/Library/Homebrew/cmd/update.rb
@@ -0,0 +1,159 @@
+module Homebrew extend self
+  def update
+    abort "Please `brew install git' first." unless system "/usr/bin/which -s git"
+
+    updater = RefreshBrew.new
+    if updater.update_from_masterbrew!
+      updater.report
+    else
+      puts "Already up-to-date."
+    end
+  end
+end
+
+class RefreshBrew
+  REPOSITORY_URL   = "http://github.com/mxcl/homebrew.git"
+  INIT_COMMAND     = "git init"
+  CHECKOUT_COMMAND = "git checkout -q master"
+  UPDATE_COMMAND   = "git pull #{REPOSITORY_URL} master"
+  REVISION_COMMAND = "git log -l -1 --pretty=format:%H 2> /dev/null"
+  GIT_UP_TO_DATE   = "Already up-to-date."
+
+  formula_regexp   = 'Library/Formula/(.+?)\.rb'
+  ADDED_FORMULA    = %r{^\s+create mode \d+ #{formula_regexp}$}
+  UPDATED_FORMULA  = %r{^\s+#{formula_regexp}\s}
+  DELETED_FORMULA  = %r{^\s+delete mode \d+ #{formula_regexp}$}
+
+  example_regexp   = 'Library/Contributions/examples/([^.\s]+).*'
+  ADDED_EXAMPLE    = %r{^\s+create mode \d+ #{example_regexp}$}
+  UPDATED_EXAMPLE  = %r{^\s+#{example_regexp}}
+  DELETED_EXAMPLE  = %r{^\s+delete mode \d+ #{example_regexp}$}
+
+  attr_reader :added_formulae, :updated_formulae, :deleted_formulae, :initial_revision
+  attr_reader :added_examples, :updated_examples, :deleted_examples
+
+  def initialize
+    @added_formulae, @updated_formulae, @deleted_formulae = [], [], []
+    @added_examples, @updated_examples, @deleted_examples = [], [], []
+    @initial_revision = self.current_revision
+  end
+
+  # Performs an update of the homebrew source. Returns +true+ if a newer
+  # version was available, +false+ if already up-to-date.
+  def update_from_masterbrew!
+    output = ''
+    HOMEBREW_REPOSITORY.cd do
+      if File.directory? '.git'
+        safe_system CHECKOUT_COMMAND
+      else
+        safe_system INIT_COMMAND
+      end
+      output = execute(UPDATE_COMMAND)
+    end
+
+    output.split("\n").reverse.each do |line|
+      case line
+      when ADDED_FORMULA
+        @added_formulae << $1
+      when DELETED_FORMULA
+        @deleted_formulae << $1
+      when UPDATED_FORMULA
+        @updated_formulae << $1 unless @added_formulae.include?($1) or @deleted_formulae.include?($1)
+      when ADDED_EXAMPLE
+        @added_examples << $1
+      when DELETED_EXAMPLE
+        @deleted_examples << $1
+      when UPDATED_EXAMPLE
+        @updated_examples << $1 unless @added_examples.include?($1) or @deleted_examples.include?($1)
+      end
+    end
+    @added_formulae.sort!
+    @updated_formulae.sort!
+    @deleted_formulae.sort!
+    @added_examples.sort!
+    @updated_examples.sort!
+    @deleted_examples.sort!
+
+    output.strip != GIT_UP_TO_DATE
+  end
+
+  def pending_formulae_changes?
+    !@updated_formulae.empty?
+  end
+
+  def pending_new_formulae?
+    !@added_formulae.empty?
+  end
+
+  def deleted_formulae?
+    !@deleted_formulae.empty?
+  end
+
+  def pending_examples_changes?
+    !@updated_examples.empty?
+  end
+
+  def pending_new_examples?
+    !@added_examples.empty?
+  end
+
+  def deleted_examples?
+    !@deleted_examples.empty?
+  end
+
+  def current_revision
+    HOMEBREW_REPOSITORY.cd { execute(REVISION_COMMAND).strip }
+  rescue
+    'TAIL'
+  end
+
+  def report
+    puts "Updated Homebrew from #{initial_revision[0,8]} to #{current_revision[0,8]}."
+    ## New Formulae
+    if pending_new_formulae?
+      ohai "The following formulae are new:"
+      puts_columns added_formulae
+    end
+    ## Deleted Formulae
+    if deleted_formulae?
+      ohai "The following formulae were removed:"
+      puts_columns deleted_formulae
+    end
+    ## Updated Formulae
+    if pending_formulae_changes?
+      ohai "The following formulae were updated:"
+      puts_columns updated_formulae
+    else
+      puts "No formulae were updated."
+    end
+    ## New examples
+    if pending_new_examples?
+      ohai "The following external commands are new:"
+      puts_columns added_examples
+    end
+    ## Deleted examples
+    if deleted_examples?
+      ohai "The following external commands were removed:"
+      puts_columns deleted_examples
+    end
+    ## Updated Formulae
+    if pending_examples_changes?
+      ohai "The following external commands were updated:"
+      puts_columns updated_examples
+    else
+      puts "No external commands were updated."
+    end
+  end
+
+  private
+
+  def execute(cmd)
+    out = `#{cmd}`
+    if $? && !$?.success?
+      puts out
+      raise "Failed while executing #{cmd}"
+    end
+    ohai(cmd, out) if ARGV.verbose?
+    out
+  end
+end