lib/key_tree.rb in key_tree-0.2.0 vs lib/key_tree.rb in key_tree-0.3.0

@@ -20,6 +20,64 @@
       KeyTree::Forest[*contents]
     else
       raise ArgumentError, "can't load #{contents.class} into a KeyTree"
     end
   end
+
+  # Load a KeyTree from some external serialization
+  #
+  # load +type+: +serialization+
+  #
+  # +type+ is upcased to form a class name that should provide a
+  # +.load+ class method (like YAML or JSON does).
+  #
+  # Example:
+  #   load(yaml: "---\na: 1\n")
+  # => {"a" => 1}
+  #
+  def self.load(typed_serialization = {})
+    unless typed_serialization.size == 1
+      raise ArgumentError, "pick one: #{typed_serialization.keys}"
+    end
+
+    type, serialization = typed_serialization.flatten
+
+    loader = get_loader(type)
+    self[loader.load(serialization)].with_meta_data do |meta_data|
+      meta_data << { load: { type: type.to_sym,
+                             loader: loader } }
+    end
+  end
+
+  # Open an external file and load contents into a KeyTree
+  #
+  def self.open(file_name)
+    type = File.extname(file_name)[/[^.]+/]
+    keytree = File.open(file_name, mode: 'rb:utf-8') do |file|
+      load_from_file(file, type)
+    end
+
+    return keytree unless block_given?
+    yield(keytree)
+  end
+
+  private_class_method
+
+  # Get a class for loading external serialization for +type+
+  # +require+s the class provider if necessary.
+  #
+  def self.get_loader(type)
+    Class.const_get(type.upcase)
+  rescue NameError
+    require type.to_s
+    retry
+  end
+
+  def self.load_from_file(file, type)
+    load(type => file.read).with_meta_data do |meta_data|
+      file_path = file.path
+      meta_data << { file: { path: file_path,
+                             name: File.basename(file_path),
+                             dir: File.dirname(file_path) } }
+    end
+  end
 end