From 2752a5782427c7809747fb761f51e8b354e713fc Mon Sep 17 00:00:00 2001
From: Stefan Lang <langstefan@gmx.at>
Date: Mon, 3 Mar 2008 16:17:09 +0100
Subject: [PATCH] Add Decorate::AroundDecorator.

---
 Manifest.txt                     |  1 +
 lib/decorate/around_decorator.rb | 76 ++++++++++++++++++++++++++++++++++++++++
 test.rb                          | 21 +++++++++++
 3 files changed, 98 insertions(+)
 create mode 100644 lib/decorate/around_decorator.rb

diff --git a/Manifest.txt b/Manifest.txt
index ed31d1f..d18f99b 100644
--- a/Manifest.txt
+++ b/Manifest.txt
@@ -12,3 +12,4 @@ lib/decorate/public_method.rb
 lib/decorate/module_method.rb
 lib/decorate/memoize.rb
 lib/decorate/before_decorator.rb
+lib/decorate/around_decorator.rb
diff --git a/lib/decorate/around_decorator.rb b/lib/decorate/around_decorator.rb
new file mode 100644
index 0000000..4ae5f26
--- /dev/null
+++ b/lib/decorate/around_decorator.rb
@@ -0,0 +1,76 @@
+require "decorate"
+require "decorate/create_alias"
+
+module Decorate::AroundDecorator
+
+  # An AroundCall holds the auxiliary information that is passed as
+  # argument to an around method.
+  class AroundCall
+
+    # Receiving object.
+    attr_reader :receiver
+
+    # The message that was sent resulting in this around call.
+    attr_reader :message
+
+    # The name of the method that constitutes the "core" behaviour
+    # (behaviour without the around logic).
+    attr_reader :wrapped_message
+
+    # Original argument list.
+    attr_reader :args
+
+    # Original block.
+    attr_reader :block
+
+    # Holds the result of a transfer to the wrapped method.
+    attr_reader :result
+
+    def initialize(receiver, message, wrapped_message, args, block)
+      @receiver = receiver
+      @message = message
+      @wrapped_message = wrapped_message
+      @args = args
+      @block = block
+      @result = nil
+    end
+
+    # Call the wrapped method. +args+ and +block+ default to original
+    # ones passed by client code. The return value of the wrapped
+    # method is stored in the +result+ attribute and also returned
+    # from transfer.
+    def transfer(args = @args, &block)
+      block ||= @block
+      @result = @receiver.__send__(@wrapped_message, *args, &block)
+    end
+
+  end
+  
+  def around_decorator(decorator_name, opts) #:doc:
+    around_method_name = opts[:call]
+    unless around_method_name.kind_of?(Symbol)
+      raise "Option :call with Symbol argument required"
+    end
+    unkown_opt = opts.keys.find { |opt| ![:call].include?(opt) }
+    if unkown_opt
+      raise "Unknown option #{unknown_opt.inspect}"
+    end
+
+    self.class.send(:define_method, decorator_name) {
+      Decorate.decorate { |klass, method_name|
+        wrapped_method_name =
+          Decorate.create_alias(klass, method_name, decorator_name)
+        klass.class_eval <<-EOF, __FILE__, __LINE__
+          def #{method_name}(*args, &block)
+            call = Decorate::AroundDecorator::AroundCall.new(
+                     self, :#{method_name}, :#{wrapped_method_name},
+                     args, block)
+            __send__(:#{around_method_name}, call)
+          end
+        EOF
+      }
+    }
+  end
+  private :around_decorator
+
+end
diff --git a/test.rb b/test.rb
index ebe0791..991894d 100644
--- a/test.rb
+++ b/test.rb
@@ -97,3 +97,24 @@ class Bf
   end
 
 end
+
+require "decorate/around_decorator"
+class Ad
+  extend Decorate::AroundDecorator
+
+  around_decorator :wrap, :call => :wrap
+
+  def wrap(call)
+    puts "Before #{call.inspect}"
+    call.transfer
+    puts "After #{call.inspect}"
+    call.result + 1
+  end
+
+  wrap
+  def foo(*args, &block)
+    puts "foo: #{args.inspect}, block: #{block.inspect}"
+    rand 10
+  end
+
+end
-- 
2.11.4.GIT