datamapper_repository_lock.rb

module DataMapper::RepositoryLock

  # Places a repository_lock method on the including class, which can
  # be executed given a repository name as an argument.
  def self.append_features(base)
    super
    base.extend(ClassMethods)
  end
  
  module ClassMethods
    # Locks the model to the given named repository.
    def repository_lock(repo)
      extend DataMapper::RepositoryLock::SingletonMethods
      include DataMapper::RepositoryLock::InstanceMethods

      cattr_accessor :lock_to_repository
      self.lock_to_repository = repo
    end
  end
  
  module SingletonMethods
    # The following methods are intended to be a stable, repository-safe frontend
    # that rescue you from from having to put repository blocks absolutely fucking 
    # everywhere in the application.

    # Override the finder methods to always use the @@lock_to_repository_name repository regardless of the
    # contents of DataMapper's repository context stack.
    def first(*args); DataMapper.repository(lock_to_repository) { super }; end
    def all(*args);   DataMapper.repository(lock_to_repository) { super }; end
    def count(*args); DataMapper.repository(lock_to_repository) { super }; end
    
    # Also sets the default repository name, which you may override locally.
    def default_repository_name; lock_to_repository; end
  end
  
  module InstanceMethods
    # Overrides the #save method to save all objects to the @@lock_to_repository_name repostory regardless
    # of the contents of DataMapper's repository context stack.
    def save(*args);    DataMapper.repository(self.class.lock_to_repository) { super }; end
    def valid?(*args);  DataMapper.repository(self.class.lock_to_repository) { super }; end
  end
  
end