build/generator/util/executable.py

   1 #
   2 # executable.py -- Utilities for dealing with external executables
   3 #
   4
   5 import os, string
   6
   7 def exists(file):
   8   """Is this an executable file?"""
   9   return os.path.isfile(file) and os.access(file, os.X_OK)
  10
  11 def find(file, dirs=None):
  12   """Search for an executable in a given list of directories.
  13      If no directories are given, search according to the PATH
  14      environment variable."""
  15   if not dirs:
  16     dirs = string.split(os.environ["PATH"], os.pathsep)
  17   for path in dirs:
  18     if is_executable(os.path.join(path, file)):
  19       return os.path.join(path, file)
  20     elif is_executable(os.path.join(path, "%s.exe" % file)):
  21       return os.path.join(path, "%s.exe" % file)
  22   return None
  23
  24 def output(cmd, strip=None):
  25   """Run a command and collect all output"""
  26   try:
  27     # Python 2.x
  28     stdin, stdout = os.popen4(cmd)
  29     assert(not stdin.close())
  30   except AttributeError:
  31     try:
  32       # Python 1.x on Unix
  33       import posix
  34       stdout = posix.popen('%s 2>&1' % cmd)
  35     except ImportError:
  36       # Python 1.x on Windows (no cygwin)
  37       # There's no easy way to collect output from stderr, so we'll
  38       # just collect stdout.
  39       stdout = os.popen(cmd)
  40   output = stdout.read()
  41   assert(not stdout.close())
  42   if strip:
  43     return string.strip(output)
  44   else:
  45     return output
  46
  47 def run(cmd):
  48   """Run a command"""
  49   exit_code = os.system(cmd)
  50   assert(not exit_code)