Suffixes = [ ".exe" ]

def findExecutable(name, alwaysAddSuffix=False):
	"""Find an executable file matching given name.
	
	Directories on the PATH environment variable are checked first,
	followed by a list of "standard" directories."""

	import os, os.path
	execNames = _getExecNames(name, alwaysAddSuffix)
	path = os.getenv("PATH", os.defpath)
	pathList = path.split(os.pathsep)
	for p in pathList:
		for e in execNames:
			filename = os.path.join(p, e)
			if os.access(filename, os.X_OK):
				return filename
	return _findInstalledApp(execNames)

def _getExecNames(name, alwaysAddSuffix):
	import os.path
	if not alwaysAddSuffix:
		root, suffix = os.path.split(name)
		if not suffix:
			alwaysAddSuffix = True
	if alwaysAddSuffix:
		execNames = [ name + suffix for suffix in Suffixes ]
		execNames.insert(0, name)
	else:
		execNames = [ name ]
	return execNames

import sys
if sys.platform == "win32":
	import os, os.path
	InstallDirs = []
	pf = os.path.join(os.path.splitdrive(sys.executable)[0],
				os.sep, "Program Files")
	try:
		dirList = os.listdir(pf)
	except OSError:
		pass
	else:
		for dname in dirList:
			dir = os.path.join(instDir, dname)
			if os.path.isdir(dir):
				InstallDirs.append(dir)
else:
	InstallDirs = [
		"/usr/local/bin",
		"/usr/bin"
		"/bin",
	]

def _findInstalledApp(execNames):
	import os, os.path
	for dir in InstallDirs:
		for e in execNames:
			filename = os.path.join(dir, e)
			if os.access(filename, os.X_OK):
				return filename
	return None