sdmenu

#!/usr/bin/ruby
#
# Author: Sage Imel <sage@iloveco.ws>
#
#
#    Copyright (C) 2011 Sage Imel
#
#    Sdmenu is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    Sdmenu is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#-------------------------------------------------------------------------
#

PATH_BIN = "/usr/bin/dmenu_path"
LIST_PATH = ENV["HOME"]+"/.sdmenu_list"


#Parse the list of commands and number of uses.
def parse_list list_path
  list = Hash.new
  #If the file doesn't exist, don't bother right now.
  if !File.exist? list_path
    return list
  end

  file = File.new list_path
  file.readlines.each do
    |app|
    bin, uses = app.split /\s+/
    list[bin] = uses.to_i
  end
  file.close

  return list
end



#Merge the cached list of commands with the new contents of the path. 
#Remove no longer existant commands from the cache.
def merge_new list, raw_apps
  new_list = Hash.new

  raw_apps.each do
    |app|
    if list[app].class == NilClass
      new_list[app] = 0
    else
      new_list[app] = list[app]
    end
  end
  return new_list
end



#Sorts the commands in the list by number of uses. Returns an array...
def sort_list list
  list.sort{|a,b| b[1]<=>a[1]}
end



#Writes out the current command cache to the file.
def write_out_list list, list_path
  output = File.new list_path, "w"
  if list.class == Array
    list.each do
      |app|
      output.puts "#{app[0]} #{app[1]}"
    end
  elsif list.class == Hash
    list.each do
      |app,count|
      output.puts "#{app} #{count}"
    end
  end
  output.flush
  output.close
end



#Prints the list of commands to standard output.
def print_list list
  list.each do
    |app|
    puts app[0]
  end
end



#Update the command list to refect one additional use.
def increment list, entry
  if list[entry].class != NilClass
    list[entry] += 1
  end
end



#Parse a command from standard input.
def read_command
  input = STDIN.read
  input.strip!
  if /(.*?)[ \t]/ =~ input
    command = $1
  else
    command = input
  end
  return [input, command]
end



#Parse the list.
if ARGV[0] == "--parse" or ARGV[0] == "-p"
  list = parse_list LIST_PATH
  raw_apps = `#{PATH_BIN}`.split "\n"
  list = merge_new list, raw_apps
  list = sort_list list
  write_out_list list, LIST_PATH
  print_list list
  exit 0
#Execute a command.
elsif ARGV[0] == "--run" or ARGV[0] == "-r"
  raw_command, command = read_command

  #Run the requested command in a seperate thread
  process = fork {
    begin
      exec raw_command
    rescue
      exit 1
    end
  }

  #Wait for the file to be available to write too (since it's probably still being used)...
  busy = true
  while busy
    `fuser #{LIST_PATH} $> /dev/null`
    if $? != 0
      busy = false
    end
    sleep(0.01)
  end

  #Update the list to reflect the new usage.
  list = parse_list LIST_PATH
  increment list, command
  write_out_list list, LIST_PATH

  #Reap child process and return it's exit status.
  Process.waitpid(process)
  exit $?.exitstatus

#Help command.
elsif ARGV[0] == "--help"
puts "Usage: sdmenu [OPTION]
Sorts command in dmenu from most frequently used to least.
  -p, --parse  parses current dmenu path and merges result with current command list 
  -r, --run    updates the command list with the command given on standard input, 
               then switches control to it
      --help    display this help and exit

This does nothing without being given any arguments.

Examples:
  sdmenu -p | dmenu | sdmenu -r  It's intended usage. Parses the dmenu_path, updates
                                 the cache, pipes the output to dmenu, updates the cache
                                 to reflect the new usage and runs the command."
  exit 0

#Invalid or no command given.
else
  STDERR.puts "Invalid command
Try `sdmenu --help' for more information."
  exit 1
end