From 36643c1ab117173a3a0d40628af501ac21ed0fb2 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 25 Nov 2018 21:17:11 -0500
Subject: [PATCH] add Util module and Util.make_relative_path()

---
 lib/rscons.rb             |  1 +
 lib/rscons/environment.rb | 10 +---------
 lib/rscons/util.rb        | 26 ++++++++++++++++++++++++++
 3 files changed, 28 insertions(+), 9 deletions(-)
 create mode 100644 lib/rscons/util.rb

diff --git a/lib/rscons.rb b/lib/rscons.rb
index d6884a9..067bd23 100644
--- a/lib/rscons.rb
+++ b/lib/rscons.rb
@@ -8,6 +8,7 @@ require_relative "rscons/environment"
 require_relative "rscons/job_set"
 require_relative "rscons/script"
 require_relative "rscons/threaded_command"
+require_relative "rscons/util"
 require_relative "rscons/varset"
 require_relative "rscons/version"
 
diff --git a/lib/rscons/environment.rb b/lib/rscons/environment.rb
index 5b46fa5..47e418c 100644
--- a/lib/rscons/environment.rb
+++ b/lib/rscons/environment.rb
@@ -265,15 +265,7 @@ module Rscons
         end
       end
       unless found_match
-        if Rscons.absolute_path?(build_fname)
-          if build_fname =~ %r{^(\w):(.*)$}
-            build_fname = "#{@build_root}#{extra_path}/_#{$1}#{$2}"
-          else
-            build_fname = "#{@build_root}#{extra_path}/_#{build_fname}"
-          end
-        elsif !build_fname.start_with?("#{@build_root}/")
-          build_fname = "#{@build_root}#{extra_path}/#{build_fname}"
-        end
+        build_fname = "#{@build_root}#{extra_path}/#{Util.make_relative_path(build_fname)}"
       end
       build_fname.gsub('\\', '/')
     end
diff --git a/lib/rscons/util.rb b/lib/rscons/util.rb
new file mode 100644
index 0000000..f8f92cf
--- /dev/null
+++ b/lib/rscons/util.rb
@@ -0,0 +1,26 @@
+module Rscons
+  module Util
+    class << self
+
+      # Make a relative path corresponding to a possibly absolute one.
+      #
+      # @param path [String]
+      #   Input path that is possibly absolute.
+      #
+      # @return [String]
+      #   Relative path.
+      def make_relative_path(path)
+        if Rscons.absolute_path?(path)
+          if path =~ %r{^(\w):(.*)$}
+            "_#{$1}#{$2}"
+          else
+            "_#{path}"
+          end
+        else
+          path
+        end
+      end
+
+    end
+  end
+end