pythonnative/src/pythonnative/native_modules/battery.py at main · pythonnative/pythonnative · GitHub

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"""Battery level and charging state.

[`Battery`][pythonnative.Battery] reports the current charge fraction

(``0.0`` to ``1.0``, or ``-1.0`` when the platform doesn't know) and

charging state, and lets you subscribe to changes. Both getters read a

value the OS already holds, so they are synchronous. The native

``Battery`` module pushes a ``change`` event with ``{"level", "state"}``;

off device, tests drive the same path through

[`dispatch_battery`][pythonnative.native_modules.battery.dispatch_battery].

"""

from __future__ import annotations

from typing import Any, Callable, Dict, List

from .. import diagnostics

from .registry import native_module, on_event

BatteryState = str # "unknown" | "unplugged" | "charging" | "full"

_listeners: List[Callable[[Dict[str, object]], None]] = []

class Battery:

"""Battery interface (synchronous getters + change listener).

Raises:

NativeModuleError: If the native module fails.

"""

@staticmethod

def get_level() -> float:

"""Return the charge fraction in ``[0, 1]``, or ``-1.0`` when the platform can't report it."""

level = float(native_module("Battery").call("get_level"))

return level if 0.0 <= level <= 1.0 else -1.0

@staticmethod

def get_state() -> BatteryState:

"""Return ``"charging"`` / ``"full"`` / ``"unplugged"`` / ``"unknown"``."""

state = str(native_module("Battery").call("get_state") or "unknown")

return state if state in ("unknown", "unplugged", "charging", "full") else "unknown"

@staticmethod

def add_listener(callback: Callable[[Dict[str, object]], None]) -> Callable[[], None]:

"""Subscribe to battery changes; returns an unsubscribe fn.

Each callback receives ``{"level": float, "state": str}``.

"""

_listeners.append(callback)

def _unsubscribe() -> None:

try:

_listeners.remove(callback)

except ValueError:

pass

return _unsubscribe

def dispatch_battery(level: float, state: BatteryState) -> None:

"""Notify listeners of a battery change."""

payload: Dict[str, object] = {"level": level, "state": state}

for listener in list(_listeners):

try:

listener(dict(payload))

except Exception:

diagnostics.swallowed("battery.dispatch_battery")

def _on_native_change(payload: Any) -> None:

if isinstance(payload, dict):

dispatch_battery(float(payload.get("level", -1.0)), str(payload.get("state", "unknown")))

on_event("Battery", "change", _on_native_change)

pythonnative/src/pythonnative/native_modules/battery.py at main · pythonnative/pythonnative · GitHub

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