python 自定义launch脚本

"""
 ###################################################################################
 launch Python programs with command lines and reusable launcher scheme classes;
 auto inserts "python" and/or path to Python executable at front of command line;
 some of this module may assume 'python' is on your system path (see Launcher.py);
subprocess module would work too, but os.popen() uses it internally, and the goal
 is to start a program running independently here, not to connect to its streams;
 multiprocessing module also is an option, but this is command-lines, not functions:
 doesn't make sense to start a process which would just do one of the options here;
new in this edition: runs script filename path through normpath() to change any
 / to \ for Windows tools where required; fix is inherited by PyEdit and others;
 on Windows, / is generally allowed for file opens, but not by all launcher tools;
 ###################################################################################
 """
import sys, os
 pyfile = (sys.platform[:3] == 'win' and 'python.exe') or 'python'
 pypath = sys.executable     # use sys in newer pys
def fixWindowsPath(cmdline):
 """
 change all / to \ in script filename path at front of cmdline;
 used only by classes which run tools that require this on Windows;
 on other platforms, this does not hurt (e.g., os.system on Unix);
 """
 splitline = cmdline.lstrip().split(' ')           # split on spaces
 fixedpath = os.path.normpath(splitline[0])        # fix forward slashes
 return ' '.join([fixedpath] + splitline[1:])      # put it back together
class LaunchMode:
 """
 on call to instance, announce label and run command;
 subclasses format command lines as required in run();
 command should begin with name of the Python script
 file to run, and not with "python" or its full path;
 """
 def init(self, label, command):
 self.what  = label
 self.where = command
 def call(self):                     # on call, ex: button press callback
 self.announce(self.what)
 self.run(self.where)                # subclasses must define run()
 def announce(self, text):               # subclasses may redefine announce()
 print(text)                         # methods instead of if/elif logic
 def run(self, cmdline):
 assert False, 'run must be defined'
class System(LaunchMode):
 """
 run Python script named in shell command line
 caveat: may block caller, unless & added on Unix
 """
 def run(self, cmdline):
 cmdline = fixWindowsPath(cmdline)
 os.system('%s %s' % (pypath, cmdline))
class Popen(LaunchMode):
 """
 run shell command line in a new process
 caveat: may block caller, since pipe closed too soon
 """
 def run(self, cmdline):
 cmdline = fixWindowsPath(cmdline)
 os.popen(pypath + ' ' + cmdline)           # assume nothing to be read
class Fork(LaunchMode):
 """
 run command in explicitly created new process
 for Unix-like systems only, including cygwin
 """
 def run(self, cmdline):
 assert hasattr(os, 'fork')
 cmdline = cmdline.split()                  # convert string to list
 if os.fork() == 0:                         # start new child process
 os.execvp(pypath, [pyfile] + cmdline)  # run new program in child
class Start(LaunchMode):
 """
 run command independent of caller
 for Windows only: uses filename associations
 """
 def run(self, cmdline):
 assert sys.platform[:3] == 'win'
 cmdline = fixWindowsPath(cmdline)
 os.startfile(cmdline)
class StartArgs(LaunchMode):
 """
 for Windows only: args may require real start
 forward slashes are okay here
 """
 def run(self, cmdline):
 assert sys.platform[:3] == 'win'
 os.system('start ' + cmdline)              # may create pop-up window
class Spawn(LaunchMode):
 """
 run python in new process independent of caller
 for Windows or Unix; use P_NOWAIT for dos box;
 forward slashes are okay here
 """
 def run(self, cmdline):
 os.spawnv(os.P_DETACH, pypath, (pyfile, cmdline))
class Top_level(LaunchMode):
 """
 run in new window, same process
 tbd: requires GUI class info too
 """
 def run(self, cmdline):
 assert False, 'Sorry - mode not yet implemented'

pick a "best" launcher for this platform
may need to specialize the choice elsewhere

if sys.platform[:3] == 'win':
 PortableLauncher = Spawn
 else:
 PortableLauncher = Fork
class QuietPortableLauncher(PortableLauncher):
 def announce(self, text):
 pass
def selftest():
 file = 'echo.py'
 input('default mode...')
 launcher = PortableLauncher(file, file)
 launcher()                                             # no block
input('system mode...')
System(file, file)()                                   # blocks

if sys.platform[:3] == 'win':
    input('DOS start mode...')                         # no block
    StartArgs(file, file)()
if name == 'main': selftest()