diff --git a/ChangeLog b/ChangeLog
index fba9014f09..296da1bdf6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Mar 13 17:48:43 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* tool/file2lastrev.rb: refactord.  fixed changed revision of git.
+
 Sat Mar 13 15:44:20 2010  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 	* io.c (rb_io_print): should not print field separator at the end
@@ -11,7 +15,7 @@ Sat Mar 13 14:49:55 2010  Yukihiro Matsumoto  <matz@ruby-lang.org>
 
 Sat Mar 13 12:26:13 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
-	* include/ruby/io.h (MakeOpenFile): finalize fptr get rid of
+	* include/ruby/io.h (MakeOpenFile): finalize fptr to get rid of
 	  memory leak.
 
 Sat Mar 13 11:14:26 2010  Shugo Maeda  <shugo@ruby-lang.org>
diff --git a/tool/file2lastrev.rb b/tool/file2lastrev.rb
index e913783d71..66a13b457a 100755
--- a/tool/file2lastrev.rb
+++ b/tool/file2lastrev.rb
@@ -5,47 +5,77 @@ ENV.delete('PWD')
 require 'optparse'
 require 'pathname'
 
-SRCDIR = Pathname(File.dirname($0)).parent.freeze
-class VCSNotFoundError < RuntimeError; end
+Program = Pathname($0)
 
-def detect_vcs(path)
-  path = SRCDIR
-  return :svn, path.relative_path_from(SRCDIR) if File.directory?("#{path}/.svn")
-  return :git_svn, path.relative_path_from(SRCDIR) if File.directory?("#{path}/.git/svn")
-  return :git, path.relative_path_from(SRCDIR) if File.directory?("#{path}/.git")
-  raise VCSNotFoundError, "does not seem to be under a vcs"
-end
+class VCS
+  class NotFoundError < RuntimeError; end
 
-# return a pair of strings, the last revision and the last revision in which
-# +path+ was modified.
-def get_revisions(path)
-  vcs, path = detect_vcs(path)
+  @@dirs = []
+  def self.register(dir)
+    @@dirs << [dir, self]
+  end
 
-  info = case vcs
-  when :svn
-    info_xml = `cd "#{SRCDIR}" && svn info --xml "#{path}"`
-    _, last, _, changed, _ = info_xml.split(/revision="(\d+)"/)
+  def self.detect(path)
+    @@dirs.sort.reverse_each do |dir, klass|
+      return klass.new(path) if File.directory?("#{path}/#{dir}")
+    end
+    raise VCS::NotFoundError, "does not seem to be under a vcs: #{path}"
+  end
+
+  def initialize(path)
+    @srcdir = path
+  end
+
+  # return a pair of strings, the last revision and the last revision in which
+  # +path+ was modified.
+  def get_revisions(path)
+    path = relative_to(path)
+    last, changed = Dir.chdir(@srcdir) {yield path}
+    last or raise "last revision not found"
+    changed or raise "changed revision not found"
     return last, changed
-  when :git_svn
-    `cd "#{SRCDIR}" && git svn info "#{path}"`
-  when :git
-    git_log = `cd "#{SRCDIR}" && git log HEAD~1..HEAD "#{path}"`
-    git_log =~ /git-svn-id: .*?@(\d+)/
-    return $1, $1
   end
 
-  if /^Revision: (\d+)/ =~ info
-    last = $1 
-  else
-    raise "last revision not found"
-  end
-  if /^Last Changed Rev: (\d+)/ =~ info
-    changed = $1
-  else
-    raise "changed revision not found"
+  def relative_to(path)
+    path ? Pathname(path).relative_path_from(@srcdir) : '.'
   end
 
-  return last, changed
+  class SVN < self
+    register(".svn")
+
+    def get_revisions(path)
+      super do
+        info_xml = `svn info --xml "#{path}"`
+        _, last, _, changed, _ = info_xml.split(/revision="(\d+)"/)
+        [last, changed]
+      end
+    end
+  end
+
+  class GIT_SVN < self
+    register(".git/svn")
+
+    def get_revisions(path)
+      super do
+        info = `git svn info "#{path}"`
+        [info[/^Revision: (\d+)/, 1], info[/^Last Changed Rev: (\d+)/, 1]]
+      end
+    end
+  end
+
+  class GIT < self
+    register(".git")
+
+    def get_revisions(path)
+      logcmd = %Q[git log -n1 --grep='^ *git-svn-id: .*@[0-9][0-9]* ']
+      idpat = /git-svn-id: .*?@(\d+) \S+\Z/
+      super do
+        last = `#{logcmd}`[idpat, 1]
+        changed = path ? `#{logcmd} "#{path}"`[idpat, 1] : last
+        [last, changed]
+      end
+    end
+  end
 end
 
 @output = nil
@@ -57,27 +87,33 @@ def self.output=(output)
 end
 @suppress_not_found = false
 
+srcdir = nil
 parser = OptionParser.new {|opts|
+  opts.on("--srcdir=PATH", "use PATH as source directory") do |path|
+    srcdir = path
+  end
   opts.on("--changed", "changed rev") do
     self.output = :changed
   end
-  opts.on("--revision.h") do
+  opts.on("--revision.h", "RUBY_REVISION macro") do
     self.output = :revision_h
   end
-  opts.on("--doxygen") do
+  opts.on("--doxygen", "Doxygen format") do
     self.output = :doxygen
   end
   opts.on("-q", "--suppress_not_found") do
     @suppress_not_found = true
   end
 }
-parser.parse!
-
+parser.parse! rescue abort "#{Program.basename}: #{$!}\n#{parser}"
 
+srcdir = (srcdir ? Pathname(srcdir) : Program.parent.parent).freeze
 begin
-  last, changed = get_revisions(ARGV.shift)
-rescue VCSNotFoundError
-  raise unless @suppress_not_found
+  vcs = VCS.detect(srcdir)
+rescue VCS::NotFoundError => e
+  abort "#{Program.basename}: #{e.message}" unless @suppress_not_found
+else
+  last, changed = vcs.get_revisions(ARGV.shift)
 end
 
 case @output