1 files changed, 101 insertions, 0 deletions
diff --git a/tool/lib/path.rb b/tool/lib/path.rb
new file mode 100644
index 0000000000..5582b2851e
--- /dev/null
+++ b/tool/lib/path.rb
@@ -0,0 +1,101 @@
+module Path
+  module_function
+
+  def clean(path)
+    path = "#{path}/".gsub(/(\A|\/)(?:\.\/)+/, '\1').tr_s('/', '/')
+    nil while path.sub!(/[^\/]+\/\.\.\//, '')
+    path
+  end
+
+  def relative(path, base)
+    path = clean(path)
+    base = clean(base)
+    path, base = [path, base].map{|s|s.split("/")}
+    until path.empty? or base.empty? or path[0] != base[0]
+      path.shift
+      base.shift
+    end
+    path, base = [path, base].map{|s|s.join("/")}
+    if base.empty?
+      path
+    elsif base.start_with?("../") or File.absolute_path?(base)
+      File.expand_path(path)
+    else
+      base.gsub!(/[^\/]+/, '..')
+      File.join(base, path)
+    end
+  end
+
+  def clean_link(src, dest)
+    begin
+      link = File.readlink(dest)
+    rescue
+    else
+      return if link == src
+      File.unlink(dest)
+    end
+    yield src, dest
+  end
+
+  # Extensions to FileUtils
+
+  module Mswin
+    def ln_safe(src, dest, *opt)
+      cmd = ["mklink", dest.tr("/", "\\"), src.tr("/", "\\")]
+      cmd[1, 0] = opt
+      return if system("cmd", "/c", *cmd)
+      # TODO: use RUNAS or something
+      puts cmd.join(" ")
+    end
+
+    def ln_dir_safe(src, dest)
+      ln_safe(src, dest, "/d")
+    end
+  end
+
+  module HardlinkExcutable
+    def ln_exe(src, dest)
+      ln(src, dest, force: true)
+    end
+  end
+
+  def ln_safe(src, dest)
+    ln_sf(src, dest)
+  rescue Errno::ENOENT
+    # Windows disallows to create broken symboic links, probably because
+    # it is a kind of reparse points.
+    raise if File.exist?(src)
+  end
+
+  alias ln_dir_safe ln_safe
+  alias ln_exe ln_safe
+
+  def ln_relative(src, dest, executable = false)
+    return if File.identical?(src, dest)
+    parent = File.dirname(dest)
+    File.directory?(parent) or mkdir_p(parent)
+    if executable
+      return (ln_exe(src, dest) if File.exist?(src))
+    end
+    clean_link(relative(src, parent), dest) {|s, d| ln_safe(s, d)}
+  end
+
+  def ln_dir_relative(src, dest)
+    return if File.identical?(src, dest)
+    parent = File.dirname(dest)
+    File.directory?(parent) or mkdir_p(parent)
+    clean_link(relative(src, parent), dest) {|s, d| ln_dir_safe(s, d)}
+  end
+
+  case (CROSS_COMPILING || RUBY_PLATFORM)
+  when /linux|darwin|solaris/
+    prepend HardlinkExcutable
+    extend HardlinkExcutable
+  when /mingw|mswin/
+    unless File.respond_to?(:symlink)
+      prepend Mswin
+      extend Mswin
+    end
+  else
+  end
+end