bin/Command.py

   1 #!/usr/bin/env python
   2 #
   3 # XXX Python script template
   4 #
   5 # XXX Describe what the script does here.
   6 #
   7 import getopt
   8 import os
   9 import shlex
  10 import sys
  11
  12 class Usage(Exception):
  13     def __init__(self, msg):
  14         self.msg = msg
  15
  16 class CommandRunner:
  17     """
  18     Representation of a command to be executed.
  19     """
  20
  21     def __init__(self, dictionary={}):
  22         self.subst_dictionary(dictionary)
  23
  24     def subst_dictionary(self, dictionary):
  25         self._subst_dictionary = dictionary
  26
  27     def subst(self, string, dictionary=None):
  28         """
  29         Substitutes (via the format operator) the values in the specified
  30         dictionary into the specified command.
  31
  32         The command can be an (action, string) tuple.  In all cases, we
  33         perform substitution on strings and don't worry if something isn't
  34         a string.  (It's probably a Python function to be executed.)
  35         """
  36         if dictionary is None:
  37             dictionary = self._subst_dictionary
  38         if dictionary:
  39             try:
  40                 string = string % dictionary
  41             except TypeError:
  42                 pass
  43         return string
  44
  45     def do_display(self, string):
  46         if isinstance(string, tuple):
  47             func = string[0]
  48             args = string[1:]
  49             s = '%s(%s)' % (func.__name__, ', '.join(map(repr, args)))
  50         else:
  51             s = self.subst(string)
  52         if not s.endswith('\n'):
  53             s += '\n'
  54         sys.stdout.write(s)
  55         sys.stdout.flush()
  56
  57     def do_not_display(self, string):
  58         pass
  59
  60     def do_execute(self, command):
  61         if isinstance(command, str):
  62             command = self.subst(command)
  63             cmdargs = shlex.split(command)
  64             if cmdargs[0] == 'cd':
  65                  command = (os.chdir,) + tuple(cmdargs[1:])
  66             elif cmdargs[0] == 'mkdir':
  67                  command = (os.mkdir,) + tuple(cmdargs[1:])
  68         if isinstance(command, tuple):
  69             func = command[0]
  70             args = command[1:]
  71             return func(*args)
  72         else:
  73             return os.system(command)
  74
  75     def do_not_execute(self, command):
  76         pass
  77
  78     display = do_display
  79     execute = do_execute
  80
  81     def run(self, command, display=None):
  82         """
  83         Runs this command, displaying it first.
  84
  85         The actual display() and execute() methods we call may be
  86         overridden if we're printing but not executing, or vice versa.
  87         """
  88         if display is None:
  89             display = command
  90         self.display(display)
  91         return self.execute(command)
  92
  93 def main(argv=None):
  94     if argv is None:
  95         argv = sys.argv
  96
  97     short_options = 'hnq'
  98     long_options = ['help', 'no-exec', 'quiet']
  99
 100     helpstr = """\
 101 Usage:  script-template.py [-hnq]
 102
 103   -h, --help                    Print this help and exit
 104   -n, --no-exec                 No execute, just print command lines
 105   -q, --quiet                   Quiet, don't print command lines
 106 """
 107
 108     try:
 109         try:
 110             opts, args = getopt.getopt(argv[1:], short_options, long_options)
 111         except getopt.error as msg:
 112             raise Usage(msg)
 113
 114         for o, a in opts:
 115             if o in ('-h', '--help'):
 116                 print(helpstr)
 117                 sys.exit(0)
 118             elif o in ('-n', '--no-exec'):
 119                 Command.execute = Command.do_not_execute
 120             elif o in ('-q', '--quiet'):
 121                 Command.display = Command.do_not_display
 122     except Usage as err:
 123         sys.stderr.write(err.msg)
 124         sys.stderr.write('use -h to get help')
 125         return 2
 126
 127     commands = [
 128     ]
 129
 130     for command in [ Command(c) for c in commands ]:
 131         status = command.run(command)
 132         if status:
 133             sys.exit(status)
 134
 135 if __name__ == "__main__":
 136     sys.exit(main())
 137
 138 # Local Variables:
 139 # tab-width:4
 140 # indent-tabs-mode:nil
 141 # End:
 142 # vim: set expandtab tabstop=4 shiftwidth=4: