From d6fb95b06f960e4cd11cf0aeadfd1a0c52cba060 Mon Sep 17 00:00:00 2001
From: Joshua Peek <josh@joshpeek.com>
Date: Mon, 23 Jul 2012 12:13:08 -0500
Subject: [PATCH] Add nested md5 digest

---
 lib/linguist/md5.rb | 50 ++++++++++++++++++++++++++++++++++++++
 test/test_md5.rb    | 59 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 lib/linguist/md5.rb
 create mode 100644 test/test_md5.rb

diff --git a/lib/linguist/md5.rb b/lib/linguist/md5.rb
new file mode 100644
index 00000000..4860bcda
--- /dev/null
+++ b/lib/linguist/md5.rb
@@ -0,0 +1,50 @@
+require 'digest/md5'
+
+module Linguist
+  module MD5
+    # Public: Create deep nested digest of value object.
+    #
+    # Useful for object comparsion.
+    #
+    # obj - Object to digest.
+    #
+    # Returns String hex digest
+    def self.hexdigest(obj)
+      digest = Digest::MD5.new
+      digest_strings(obj).each { |e| digest.update(e) }
+      digest.hexdigest
+    end
+
+    # Internal: Get String representations for digest.
+    #
+    # obj - Object to digest
+    #
+    # Returns an Array of Strings.
+    def self.digest_strings(obj)
+      case obj
+      when String
+        ["#{obj.class}", "#{obj}"]
+      when Symbol
+        ["#{obj.class}", "#{obj}"]
+      when Integer
+        ["#{obj.class}", "#{obj}"]
+      when TrueClass, FalseClass, NilClass
+        ["#{obj.class}"]
+      when Array
+        r = ["#{obj.class}"]
+        obj.each do |e|
+          r.concat(digest_strings(e))
+        end
+        r
+      when Hash
+        r = ["#{obj.class}"]
+        obj.map { |k, v| digest_strings([k, v]) }.sort.each do |e|
+          r.concat(digest_strings(e))
+        end
+        r
+      else
+        raise TypeError, "can't convert #{obj.inspect} into String"
+      end
+    end
+  end
+end
diff --git a/test/test_md5.rb b/test/test_md5.rb
new file mode 100644
index 00000000..789e8b36
--- /dev/null
+++ b/test/test_md5.rb
@@ -0,0 +1,59 @@
+require 'linguist/md5'
+
+require 'test/unit'
+
+class TestMD5 < Test::Unit::TestCase
+  include Linguist
+
+  def test_hexdigest_string
+    assert_equal "af0ede4f95acad6d331a813dc3904c11", MD5.hexdigest("foo")
+    assert_equal "05427b9908edb6995ed76faa23e4471f", MD5.hexdigest("bar")
+  end
+
+  def test_hexdigest_symbol
+    assert_equal "450c1ae043459546517b3dd2f98250f0", MD5.hexdigest(:foo)
+    assert_equal "f06967526af9d7a512594b0a81b31ede", MD5.hexdigest(:bar)
+
+    assert_not_equal MD5.hexdigest("foo"), MD5.hexdigest(:foo)
+  end
+
+  def test_hexdigest_integer
+    assert_equal "7605ec17fd7fd213fdcd23cac302cbb4", MD5.hexdigest(1)
+    assert_equal "097c311a46d330e4e119ba2b1dc0f9a5", MD5.hexdigest(2)
+
+    assert_not_equal MD5.hexdigest("1"), MD5.hexdigest(1)
+  end
+
+  def test_hexdigest_boolean
+    assert_equal "a690a0615820e2e5c53901d8b8958509", MD5.hexdigest(true)
+    assert_equal "fca6a9b459e702fa93513c6a8b8c5dfe", MD5.hexdigest(false)
+
+    assert_not_equal MD5.hexdigest("true"), MD5.hexdigest(true)
+    assert_not_equal MD5.hexdigest("false"), MD5.hexdigest(false)
+  end
+
+  def test_hexdigest_nil
+    assert_equal "35589a1cc0b3ca90fc52d0e711c0c434", MD5.hexdigest(nil)
+
+    assert_not_equal MD5.hexdigest("nil"), MD5.hexdigest(nil)
+  end
+
+  def test_hexdigest_array
+    assert_equal "4410ec34d9e6c1a68100ca0ce033fb17", MD5.hexdigest([])
+    assert_equal "a57e31bc7bce57d04dd6a07e74fd0d88", MD5.hexdigest([1])
+    assert_equal "ecbda6354c6e0370df33d43ce14701f4", MD5.hexdigest([1, 2])
+    assert_equal "5c42a2601d344f359017e2b76390e2cc", MD5.hexdigest([1, 2, 3])
+    assert_equal "c1816755a379d2b32289647ad1870d12", MD5.hexdigest([1, 2, [3]])
+  end
+
+  def test_hexdigest_hash
+    assert_equal "fae8a9257e154175da4193dbf6552ef6", MD5.hexdigest({})
+    assert_equal "b3646d6d84a803baa5ee2e5354057a65", MD5.hexdigest({:a => 1})
+    assert_equal "92c08085470d42ca0d33dd3ec5a8e098", MD5.hexdigest({:b => 2})
+
+    assert_not_equal MD5.hexdigest([:b, 2]), MD5.hexdigest({:b => 2})
+
+    assert_equal MD5.hexdigest({:b => 2, :a => 1}), MD5.hexdigest({:a => 1, :b => 2})
+    assert_equal MD5.hexdigest({:c => 3, :b => 2, :a => 1}), MD5.hexdigest({:a => 1, :b => 2, :c => 3})
+  end
+end