Extract formula locks into a class

1 files changed, 40 insertions, 0 deletions

diff --git a/Library/Homebrew/formula_lock.rb b/Library/Homebrew/formula_lock.rb
new file mode 100644
index 000000000..183c2dd9c
--- /dev/null
+++ b/Library/Homebrew/formula_lock.rb
@@ -0,0 +1,40 @@
+class FormulaLock
+  LOCKDIR = HOMEBREW_CACHE_FORMULA
+
+  def initialize(name)
+    @name = name
+    @path = LOCKDIR.join("#{@name}.brewing")
+  end
+
+  def lock
+    LOCKDIR.mkpath
+    @lockfile = get_or_create_lockfile
+    unless @lockfile.flock(File::LOCK_EX | File::LOCK_NB)
+      raise OperationInProgressError, @name
+    end
+  end
+
+  def unlock
+    unless @lockfile.nil? || @lockfile.closed?
+      @lockfile.flock(File::LOCK_UN)
+      @lockfile.close
+    end
+  end
+
+  def with_lock
+    lock
+    yield
+  ensure
+    unlock
+  end
+
+  private
+
+  def get_or_create_lockfile
+    if @lockfile.nil? || @lockfile.closed?
+      @path.open(File::RDWR | File::CREAT)
+    else
+      @lockfile
+    end
+  end
+end