"""ProcessDispatcher class declaration"""
import asyncio
import subprocess
import sys
import typing
from collections import deque
from copy import deepcopy
from functools import partial
from typing import Any as AnyType
from typing import AnyStr
from typing import Awaitable
from typing import Callable
from typing import Deque
from typing import Dict
from typing import Generic
from typing import List
from typing import Optional
from typing import Tuple
from typing import Type
from typing import Union
from . import asyncio_subprocess
from . import exceptions
from .fake_popen import AsyncFakePopen
from .fake_popen import FakePopen
from .types import COMMAND
from .utils import Command
if typing.TYPE_CHECKING:
from .fake_process import FakeProcess
__all__ = ["ProcessDispatcher"]
class ProcessDispatcher:
"""Main class for handling processes."""
process_list: List["FakeProcess"] = []
built_in_popen: Optional[Callable] = None
built_in_async_subprocess: Optional[AnyType] = None
_allow_unregistered: bool = False
_cache: Dict["FakeProcess", Dict["FakeProcess", AnyType]] = dict()
_keep_last_process: bool = False
_pid: int = 0
@classmethod
def register(cls, process: "FakeProcess") -> None:
if not cls.process_list:
cls.built_in_popen = subprocess.Popen
subprocess.Popen = FakePopenWrapper # type: ignore
cls.built_in_async_subprocess = asyncio.subprocess
asyncio.create_subprocess_shell = cls.async_shell # type: ignore
asyncio.create_subprocess_exec = cls.async_exec # type: ignore
asyncio.subprocess = asyncio_subprocess
cls._cache[process] = {
proc: deepcopy(proc.definitions) for proc in cls.process_list
}
cls.process_list.append(process)
@classmethod
def deregister(cls, process: "FakeProcess") -> None:
cls.process_list.remove(process)
cache = cls._cache.pop(process)
for proc, processes in cache.items():
proc.definitions = processes
if not cls.process_list:
subprocess.Popen = cls.built_in_popen # type: ignore
cls.built_in_popen = None
if cls.built_in_async_subprocess is None:
raise exceptions.PluginInternalError
asyncio.subprocess = cls.built_in_async_subprocess
asyncio.create_subprocess_shell = (
cls.built_in_async_subprocess.create_subprocess_shell
)
asyncio.create_subprocess_exec = (
cls.built_in_async_subprocess.create_subprocess_exec
)
cls.built_in_async_subprocess = None
@classmethod
def dispatch(
cls, command: COMMAND, **kwargs: Optional[Dict]
) -> Union[FakePopen, subprocess.Popen]:
"""This method will be used instead of the subprocess.Popen()"""
process = cls.__dispatch(command)
if process is None:
if cls.built_in_popen is None:
raise exceptions.PluginInternalError
popen: subprocess.Popen = cls.built_in_popen(command, **kwargs)
return popen
result = cls._prepare_instance(FakePopen, command, kwargs, process)
if not isinstance(result, FakePopen):
raise exceptions.PluginInternalError
result.run_thread()
return result
@classmethod
async def async_shell(
cls, cmd: Union[str, bytes], **kwargs: Dict
) -> Union[AsyncFakePopen, asyncio.subprocess.Process]:
"""Replacement of asyncio.create_subprocess_shell()"""
if not isinstance(cmd, (str, bytes)):
raise ValueError("cmd must be a string")
method = partial(
cls.built_in_async_subprocess.create_subprocess_shell, # type: ignore
cmd,
**kwargs
)
if isinstance(cmd, bytes):
cmd = cmd.decode()
return await cls._call_async(cmd, method, kwargs)
@classmethod
async def async_exec(
cls, program: Union[str, bytes], *args: Union[str, bytes], **kwargs: Dict
) -> Union[AsyncFakePopen, asyncio.subprocess.Process]:
"""Replacement of asyncio.create_subprocess_exec()"""
if not isinstance(program, (str, bytes)):
raise ValueError("program must be a string")
method = partial(
cls.built_in_async_subprocess.create_subprocess_exec, # type: ignore
program,
*args,
**kwargs
)
if isinstance(program, bytes):
program = program.decode()
command = [
program,
*[arg.decode() if isinstance(arg, bytes) else arg for arg in args],
]
return await cls._call_async(command, method, kwargs)
@classmethod
async def _call_async(
cls,
command: COMMAND,
async_method: Callable,
kwargs: Dict,
) -> Union[AsyncFakePopen, asyncio.subprocess.Process]:
process = cls.__dispatch(command)
if process is None:
if cls.built_in_async_subprocess is None:
raise exceptions.PluginInternalError
async_shell: Awaitable[asyncio.subprocess.Process] = async_method()
return await async_shell
if sys.platform == "win32" and isinstance(
asyncio.get_event_loop_policy().get_event_loop(), asyncio.SelectorEventLoop
):
raise NotImplementedError(
"The SelectorEventLoop doesn't support subprocess"
)
result = cls._prepare_instance(AsyncFakePopen, command, kwargs, process)
if not isinstance(result, AsyncFakePopen):
raise exceptions.PluginInternalError
result.evaluate()
return result
@classmethod
def _prepare_instance(
cls,
klass: Union[Type[FakePopen], Type[AsyncFakePopen]],
command: COMMAND,
kwargs: dict,
process: dict,
) -> Union[FakePopen, AsyncFakePopen]:
# Update the command with the actual command specified by the caller.
# This will ensure that Command objects do not end up unexpectedly in
# caller's objects (e.g. proc.args, CalledProcessError.cmd). Take care
# to preserve the dict that may still be referenced when using
# keep_last_process.
fake_popen_kwargs = process.copy()
fake_popen_kwargs["command"] = command
recorder = fake_popen_kwargs.pop("recorder")
result = klass(**fake_popen_kwargs)
recorder.calls.append(result)
result.pid = cls._pid
result.configure(**kwargs)
return result
@classmethod
def __dispatch(cls, command: COMMAND) -> Optional[dict]:
command_instance, processes, process_instance = cls._get_process(command)
if process_instance:
process_instance.calls.append(command)
if not processes:
if not cls.process_list[-1]._allow_unregistered:
raise exceptions.ProcessNotRegisteredError(
"The process '%s' was not registered."
% (
(
command
if isinstance(command, str)
else " ".join(str(item) for item in command)
),
)
)
else:
return None
process = processes.popleft()
if not processes and process_instance is not None:
if cls.process_list[-1]._keep_last_process:
processes.append(process)
elif command_instance:
del process_instance.definitions[command_instance]
cls._pid += 1
if isinstance(process, bool):
# real process will be called
return None
return process
@classmethod
def _get_process(
cls, command: COMMAND
) -> Tuple[
Optional[Command], Optional[Deque[Union[dict, bool]]], Optional["FakeProcess"]
]:
for proc in reversed(cls.process_list):
command_instance, processes = next(
(
(key, value)
for key, value in proc.definitions.items()
if key == command
),
(None, None),
)
process_instance = proc
if processes and isinstance(processes, deque):
return command_instance, processes, process_instance
return None, None, None
class FakePopenWrapper(Generic[AnyStr]):
def __new__( # type: ignore
cls, command: COMMAND, **kwargs: Optional[Dict]
) -> FakePopen:
return ProcessDispatcher.dispatch(command, **kwargs) # type: ignore
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