From a7059e47d6015f7069a987550b6b027a7dbc6a34 Mon Sep 17 00:00:00 2001
From: Gary Gabriel <ggabriel@gmail.com>
Date: Thu, 30 Oct 2008 23:10:54 -0400
Subject: [PATCH] Add support for message formatting in BufferedLogger.

---
 .../lib/active_support/buffered_logger.rb          |   10 +++++++++-
 activesupport/test/buffered_logger_test.rb         |   13 +++++++++++++
 2 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/activesupport/lib/active_support/buffered_logger.rb b/activesupport/lib/active_support/buffered_logger.rb
index 77e0b1d..40eab60 100644
--- a/activesupport/lib/active_support/buffered_logger.rb
+++ b/activesupport/lib/active_support/buffered_logger.rb
@@ -32,6 +32,7 @@ module ActiveSupport
     end
 
     attr_accessor :level
+    attr_accessor :formatter
     attr_reader :auto_flushing
 
     def initialize(log, level = DEBUG)
@@ -40,6 +41,9 @@ module ActiveSupport
       @auto_flushing = 1
       @guard = Mutex.new
 
+      # The default formatter returns the message unchanged.
+      @formatter = lambda { |severity_label, message| message }
+
       if log.respond_to?(:write)
         @log = log
       elsif File.exist?(log)
@@ -56,15 +60,19 @@ module ActiveSupport
     def add(severity, message = nil, progname = nil, &block)
       return if @level > severity
       message = (message || (block && block.call) || progname).to_s
-      # If a newline is necessary then create a new message ending with a newline.
+      # Format the message.
       # Ensures that the original message is not mutated.
+      message = @formatter.call(SEV_LABEL[severity], "#{message}")
+      # If a newline is necessary, then create a new message ending with a newline.
       message = "#{message}\n" unless message[-1] == ?\n
       buffer << message
       auto_flush
       message
     end
 
+    SEV_LABEL = {}
     for severity in Severity.constants
+      SEV_LABEL[Severity.const_get(severity)] = severity
       class_eval <<-EOT, __FILE__, __LINE__
         def #{severity.downcase}(message = nil, progname = nil, &block)
           add(#{severity}, message, progname, &block)
diff --git a/activesupport/test/buffered_logger_test.rb b/activesupport/test/buffered_logger_test.rb
index 28dd343..99157c1 100644
--- a/activesupport/test/buffered_logger_test.rb
+++ b/activesupport/test/buffered_logger_test.rb
@@ -137,4 +137,17 @@ class BufferedLoggerTest < Test::Unit::TestCase
     assert @output.string.include?("a\nb\nc\n")
     assert @output.string.include?("x\ny\nz\n")
   end
+
+  def test_default_formatter_should_not_alter_message
+    @logger.level = Logger::INFO
+    @logger.info @message
+    assert_equal "#{@message}\n", @output.string
+  end
+
+  def test_should_format_output_with_formatter
+    @logger.level = Logger::INFO
+    @logger.formatter = lambda { |severity_label, message| "[#{severity_label}] #{message}" }
+    @logger.warn @message
+    assert_equal "[WARN] #{@message}\n", @output.string
+  end
 end
-- 
1.6.0.2