1 files changed, 53 insertions, 0 deletions
diff --git a/Library/Contributions/examples/brew-unpack.rb b/Library/Contributions/examples/brew-unpack.rb
new file mode 100755
index 000000000..ab3438d1a
--- /dev/null
+++ b/Library/Contributions/examples/brew-unpack.rb
@@ -0,0 +1,53 @@
+require 'formula'
+
+module Homebrew extend self
+  def unpack
+    unpack_usage = <<-EOS
+Usage: brew unpack [--destdir=path/to/extract/in] <formulae ...>
+
+Unpack formulae source code for inspection.
+
+Formulae archives will be extracted to subfolders inside the current working
+directory or a directory specified by `--destdir`.
+    EOS
+
+    if ARGV.empty?
+      puts unpack_usage
+      exit 0
+    end
+
+    formulae = ARGV.named
+    raise FormulaUnspecifiedError if formulae.empty?
+
+    unpack_dir = ARGV.options_only.select {|o| o.start_with? "--destdir="}
+    if unpack_dir.empty?
+      unpack_dir = Pathname.new Dir.getwd
+    else
+      unpack_dir = Pathname.new(unpack_dir.first.split('=')[1]).realpath
+      unpack_dir.mkpath unless unpack_dir.exist?
+    end
+    raise "Cannot write to #{unpack_dir}" unless unpack_dir.writable?
+
+    formulae.each do |f|
+      f = Formula.factory(f)
+
+      unless f.downloader.kind_of? CurlDownloadStrategy
+        stage_dir = unpack_dir + [f.name, f.version].join('-')
+        stage_dir.mkpath unless stage_dir.exist?
+      else
+        stage_dir = unpack_dir
+      end
+
+      # Can't use a do block here without DownloadStrategy do blocks throwing:
+      #   warning: conflicting chdir during another chdir block
+      Dir.chdir stage_dir
+        f.downloader.fetch
+        f.downloader.stage
+      Dir.chdir unpack_dir
+    end
+  end
+end
+
+# Here is the actual code that gets run when `brew` loads this external
+# command.
+Homebrew.unpack