1 files changed, 15 insertions, 0 deletions
diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 2e072afff..e2fde2ef9 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -228,6 +228,21 @@ class Formula
     end
   end
 
+  def lock
+    lockpath = HOMEBREW_CACHE_FORMULA/"#{@name}.brewing"
+    @lockfile = lockpath.open(File::RDWR | File::CREAT)
+    unless @lockfile.flock(File::LOCK_EX | File::LOCK_NB)
+      raise OperationInProgressError, @name
+    end
+  end
+
+  def unlock
+    unless @lockfile.nil?
+      @lockfile.flock(File::LOCK_UN)
+      @lockfile.close
+    end
+  end
+
   def == b
     name == b.name
   end