Module spin_sdk.wit.imports.poll

A poll API intended to let users wait for I/O events on multiple handles at once.

Functions

def poll(in_: List[Pollable]) ‑> List[int]

Poll for completion on a set of pollables.

This function takes a list of pollables, which identify I/O sources of interest, and waits until one or more of the events is ready for I/O.

The result list<u32> contains one or more indices of handles in the argument list that is ready for I/O.

If the list contains more elements than can be indexed with a u32 value, this function traps.

A timeout can be implemented by adding a pollable from the wasi-clocks API to the list.

This function does not return a result; polling in itself does not do any I/O so it doesn't fail. If any of the I/O sources identified by the pollables has an error, it is indicated by marking the source as being reaedy for I/O.

Classes

class Pollable

pollable represents a single I/O event which may be ready, or not.

Expand source code

class Pollable:
    """
    `pollable` represents a single I/O event which may be ready, or not.
    """
    
    def ready(self) -> bool:
        """
        Return the readiness of a pollable. This function never blocks.
        
        Returns `true` when the pollable is ready, and `false` otherwise.
        """
        raise NotImplementedError
    def block(self) -> None:
        """
        `block` returns immediately if the pollable is ready, and otherwise
        blocks until ready.
        
        This function is equivalent to calling `poll.poll` on a list
        containing only this pollable.
        """
        raise NotImplementedError
    def __enter__(self) -> Self:
        """Returns self"""
        return self
                                
    def __exit__(self, exc_type: type[BaseException] | None, exc_value: BaseException | None, traceback: TracebackType | None) -> bool | None:
        """
        Release this resource.
        """
        raise NotImplementedError

Methods

def block(self) ‑> None

block returns immediately if the pollable is ready, and otherwise blocks until ready.

This function is equivalent to calling poll.poll on a list containing only this pollable.

def ready(self) ‑> bool

Return the readiness of a pollable. This function never blocks.

Returns true when the pollable is ready, and false otherwise.