#--
# kpathsea.rb - libkpathsea access for ruby
# Last Change: Tue May 16 17:23:14 2006
#++


module RFIL
  module TeX

    # Find TeX related files with help of the 'kpsewhich' program.
    class Kpathsea
      # _progname_ defaults to the name of the main Ruby script.
      # _progname_ is used to find program specific files as in
      # <tt>TEXINPUT.progname</tt> in the <tt>texmf.cnf</tt>.
      def initialize (progname=File.basename($0))
        raise ArgumentError if progname.match(/('|")/)
        @progname=progname
      end
      
      def reset_program_name(suffix)
        @progname=suffix
      end
      
      # Return the complete path of the file _name_. _name_ must not
      # contain single or double quotes.
      def find_file(name,fmt="tex",mustexist=false)
        raise ArgumentError if name.match(/('|")/)
        raise ArgumentError if fmt.match(/('|")/)
        runkpsewhich(name,fmt,mustexist)
      end

      # Return a File object. Raise Errno::ENOENT if file is not found. If
      # block is given, a File object is passed into the block and the
      # file gets closed when leaving the block. It behaves exactly as 
      # the File.open method.
      def open_file(name,fmt="tex")
        loc=self.find_file(name,fmt)
        raise Errno::ENOENT, "#{name}" unless loc
        if block_given?
          File.open(loc) { |file|
            yield file
          }
        else
          File.open(loc)
        end
      end
      
      private

      def runkpsewhich(name,fmt,mustexist)
        fmt.untaint
        name.untaint
        @progname.untaint
        # path or amok XXX
        cmdline= "kpsewhich -progname=\"#{@progname}\" -format=\"#{fmt}\" #{name}"
        # puts cmdline
        lines = ""
        IO.popen(cmdline) do |io|
          lines = io.readlines
        end
        return $? == 0 ? lines.to_s.chomp.untaint : nil
      end
    end
  end
end