import os
import msvcrt
import signal
import sys
import _winapi

from . import context
from . import spawn
from . import reduction
from . import util

__all__ = ['Popen']

#
#
#

TERMINATE = 0x10000
WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False))
WINSERVICE = sys.executable.lower().endswith("pythonservice.exe")

#
# We define a Popen class similar to the one from subprocess, but
# whose constructor takes a process object as its argument.
#

class Popen(object):
'''
Start a subprocess to run the code of a process object
'''
method = 'spawn'

def __init__(self, process_obj):
prep_data = spawn.get_preparation_data(process_obj._name)

# read end of pipe will be "stolen" by the child process
# -- see spawn_main() in spawn.py.
rhandle, whandle = _winapi.CreatePipe(None, 0)
wfd = msvcrt.open_osfhandle(whandle, 0)
cmd = spawn.get_command_line(parent_pid=os.getpid(),
pipe_handle=rhandle)
cmd = ' '.join('"%s"' % x for x in cmd)

with open(wfd, 'wb', closefd=True) as to_child:
# start process
try:
hp, ht, pid, tid = _winapi.CreateProcess(
spawn.get_executable(), cmd,
None, None, False, 0, None, None, None)
_winapi.CloseHandle(ht)
except:
_winapi.CloseHandle(rhandle)
raise

# set attributes of self
self.pid = pid
self.returncode = None
self._handle = hp
self.sentinel = int(hp)
util.Finalize(self, _winapi.CloseHandle, (self.sentinel,))

# send information to child
context.set_spawning_popen(self)
try:
reduction.dump(prep_data, to_child)
reduction.dump(process_obj, to_child)
finally:
context.set_spawning_popen(None)

def duplicate_for_child(self, handle):
assert self is context.get_spawning_popen()
return reduction.duplicate(handle, self.sentinel)

def wait(self, timeout=None):
if self.returncode is None:
if timeout is None:
msecs = _winapi.INFINITE
else:
msecs = max(0, int(timeout * 1000 + 0.5))

res = _winapi.WaitForSingleObject(int(self._handle), msecs)
if res == _winapi.WAIT_OBJECT_0:
code = _winapi.GetExitCodeProcess(self._handle)
if code == TERMINATE:
code = -signal.SIGTERM
self.returncode = code

return self.returncode

def poll(self):
return self.wait(timeout=0)

def terminate(self):
if self.returncode is None:
try:
_winapi.TerminateProcess(int(self._handle), TERMINATE)
except OSError:
if self.wait(timeout=1.0) is None:
raise