PStore: select checksum algorithm

* lib/pstore.rb (PStore::CHECKSUM_ALGO): find available hashing
  algorithm for checksum.  MD5 is not available in FIPS mode.
  [Feature #6943]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56284 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Wed Sep 28 23:14:19 2016  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/pstore.rb (PStore::CHECKSUM_ALGO): find available hashing
+	  algorithm for checksum.  MD5 is not available in FIPS mode.
+	  [Feature #6943]
+
 Wed Sep 28 13:00:25 2016  ksss  <co000ri@gmail.com>
 
 	* signal.c (sig_signame): [DOC] Add documentation in the case of

lib/pstore.rb

@@ -8,7 +8,7 @@
 #
 # See PStore for documentation.
 
-require "digest/md5"
+require "digest"
 
 #
 # PStore implements a file based persistence mechanism based on a Hash.  User
@@ -352,7 +352,12 @@ class PStore
 
   private
   # Constant for relieving Ruby's garbage collector.
-  CHECKSUM_ALGO = Digest::MD5
+  CHECKSUM_ALGO = %w[SHA512 SHA384 SHA256 SHA1 RMD160 MD5].each do |algo|
+    begin
+      break Digest(algo)
+    rescue LoadError
+    end
+  end
   EMPTY_STRING = ""
   EMPTY_MARSHAL_DATA = Marshal.dump({})
   EMPTY_MARSHAL_CHECKSUM = CHECKSUM_ALGO.digest(EMPTY_MARSHAL_DATA)