polka/site_scons/paths.py
2015-09-22 14:44:30 -07:00

30 lines
799 B
Python

# paths.py
# Eryn Wells <eryn@erynwells.me>
import os
import os.path
def is_executable(path):
return os.path.exists(path) and os.access(path, os.X_OK)
def which(program):
'''
Look for `program` in system path and return the full path to that binary if
it is found. Otherwise, return `None`.
'''
path, name = os.path.split(program)
if path:
if is_executable(program):
return program
else:
pathext = [''] + os.environ.get('PATHEXT', '').split(os.pathsep)
for path in os.environ.get('PATH', '').split(os.pathsep):
exe = os.path.join(path, program)
for ext in pathext:
candidate = exe + ext
if is_executable(candidate):
return candidate
return None