#!/usr/bin/ruby

# mpipe reads STDIN and pipes it to multiple processes
#
# Usage: whatever | mpipe.rb common_args -pipe pgm1 -pipe pgm2 pgm2_args
#
# pgm1 and pgm2 will all receive whatever's STDOUT on their STDIN
# All arguments appearing before the first -pipe switch will be passed to
# all called programs before their own arguments
#
# Example of a CVS loginfo entry: 
#
# \/doc\/en ( $CVSROOT/CVSROOT/mpipe.rb %{s} -pipe $CVSROOT/CVSROOT/commitlog-doc.pl -pipe $CVSROOT/CVSROOT/ciabot.pl $USER gentoo cvs-commits@gentoo.org cia@navi.cx )
#
# Current limitation: programs that expect a -pipe argument themselves cannot be called
#
# Target usage: send CVS loginfo to multiple processes


# Parse cmd line
aPipes=[]
curr=""
common=""; gotOne=false
ARGV.each {|p|
  if p == '-pipe'
    gotOne = true
    # Open current pipe cmd before starting a new one
    aPipes << IO.popen(curr, "w") if curr.length > 0
    # Init next pipe cmd
    curr = ""
  else
    # Add argument to current pipe cmd or to the common args
    if gotOne then
      curr << "#{p} #{common if curr.length == 0} "
    else
      common << "#{p} "
    end
  end
}
# Last cmd
aPipes << IO.popen(curr, "w") if curr.length > 0

# Read STDIN and send it to all opened pipes
STDIN.each { |line|
  aPipes.each { |p|
    p.puts(line)
  }
}

# Close all pipes and exit
aPipes.each {|p| p.close_write}