Coverage for /pythoncovmergedfiles/medio/medio/usr/local/lib/python3.11/site-packages/anyio/abc/_tasks.py: 93%

1from __future__ import annotations 

2 

3import sys 

4from abc import ABCMeta, abstractmethod 

5from collections.abc import Awaitable, Callable 

6from types import TracebackType 

7from typing import TYPE_CHECKING, Any, Protocol, TypeVar, overload 

8 

9if sys.version_info >= (3, 11): 

10 from typing import TypeVarTuple, Unpack 

11else: 

12 from typing_extensions import TypeVarTuple, Unpack 

13 

14if TYPE_CHECKING: 

15 from .._core._tasks import CancelScope 

16 

17T_Retval = TypeVar("T_Retval") 

18T_contra = TypeVar("T_contra", contravariant=True) 

19PosArgsT = TypeVarTuple("PosArgsT") 

20 

21 

22class TaskStatus(Protocol[T_contra]): 

23 @overload 

24 def started(self: TaskStatus[None]) -> None: ... 

25 

26 @overload 

27 def started(self, value: T_contra) -> None: ... 

28 

29 def started(self, value: T_contra | None = None) -> None: 

30 """ 

31 Signal that the task has started. 

32 

33 :param value: object passed back to the starter of the task 

34 """ 

35 

36 

37class TaskGroup(metaclass=ABCMeta): 

38 """ 

39 Groups several asynchronous tasks together. 

40 

41 :ivar cancel_scope: the cancel scope inherited by all child tasks 

42 :vartype cancel_scope: CancelScope 

43 

44 .. note:: On asyncio, support for eager task factories is considered to be 

45 **experimental**. In particular, they don't follow the usual semantics of new 

46 tasks being scheduled on the next iteration of the event loop, and may thus 

47 cause unexpected behavior in code that wasn't written with such semantics in 

48 mind. 

49 """ 

50 

51 cancel_scope: CancelScope 

52 

53 @abstractmethod 

54 def start_soon( 

55 self, 

56 func: Callable[[Unpack[PosArgsT]], Awaitable[Any]], 

57 *args: Unpack[PosArgsT], 

58 name: object = None, 

59 ) -> None: 

60 """ 

61 Start a new task in this task group. 

62 

63 :param func: a coroutine function 

64 :param args: positional arguments to call the function with 

65 :param name: name of the task, for the purposes of introspection and debugging 

66 

67 .. versionadded:: 3.0 

68 """ 

69 

70 @abstractmethod 

71 async def start( 

72 self, 

73 func: Callable[..., Awaitable[Any]], 

74 *args: object, 

75 name: object = None, 

76 ) -> Any: 

77 """ 

78 Start a new task and wait until it signals for readiness. 

79 

80 The target callable must accept a keyword argument ``task_status`` (of type 

81 :class:`TaskStatus`). Awaiting on this method will return whatever was passed to 

82 ``task_status.started()`` (``None`` by default). 

83 

84 .. note:: The :class:`TaskStatus` class is generic, and the type argument should 

85 indicate the type of the value that will be passed to 

86 ``task_status.started()``. 

87 

88 :param func: a coroutine function that accepts the ``task_status`` keyword 

89 argument 

90 :param args: positional arguments to call the function with 

91 :param name: an optional name for the task, for introspection and debugging 

92 :return: the value passed to ``task_status.started()`` 

93 :raises RuntimeError: if the task finishes without calling 

94 ``task_status.started()`` 

95 

96 .. seealso:: :ref:`start_initialize` 

97 

98 .. versionadded:: 3.0 

99 """ 

100 

101 @abstractmethod 

102 async def __aenter__(self) -> TaskGroup: 

103 """Enter the task group context and allow starting new tasks.""" 

104 

105 @abstractmethod 

106 async def __aexit__( 

107 self, 

108 exc_type: type[BaseException] | None, 

109 exc_val: BaseException | None, 

110 exc_tb: TracebackType | None, 

111 ) -> bool: 

112 """Exit the task group context waiting for all tasks to finish."""