Coverage for src/bluetooth_sig/gatt/descriptors/characteristic_extended_properties.py: 85%

1"""Characteristic Extended Properties Descriptor implementation.""" 

2 

3from __future__ import annotations 

4 

5from enum import IntFlag 

6 

7import msgspec 

8 

9from ..characteristics.utils import DataParser 

10from .base import BaseDescriptor 

11 

12 

13class ExtendedPropertiesFlags(IntFlag): 

14 """Characteristic Extended Properties flags.""" 

15 

16 RELIABLE_WRITE = 0x0001 

17 WRITABLE_AUXILIARIES = 0x0002 

18 

19 

20class CharacteristicExtendedPropertiesData(msgspec.Struct, frozen=True, kw_only=True): 

21 """Characteristic Extended Properties descriptor data.""" 

22 

23 reliable_write: bool 

24 writable_auxiliaries: bool 

25 

26 

27class CharacteristicExtendedPropertiesDescriptor(BaseDescriptor): 

28 """Characteristic Extended Properties Descriptor (0x2900). 

29 

30 Defines extended properties for a characteristic using bit flags. 

31 Indicates support for reliable writes and writable auxiliaries. 

32 """ 

33 

34 def _has_structured_data(self) -> bool: 

35 return True 

36 

37 def _get_data_format(self) -> str: 

38 return "uint16" 

39 

40 def _parse_descriptor_value(self, data: bytes) -> CharacteristicExtendedPropertiesData: 

41 """Parse Characteristic Extended Properties value. 

42 

43 Args: 

44 data: Raw bytes (should be 2 bytes for uint16) 

45 

46 Returns: 

47 CharacteristicExtendedPropertiesData with property flags 

48 

49 Raises: 

50 ValueError: If data is not exactly 2 bytes 

51 """ 

52 if len(data) != 2: 

53 raise ValueError(f"Characteristic Extended Properties data must be exactly 2 bytes, got {len(data)}") 

54 

55 # Parse as little-endian uint16 

56 value = DataParser.parse_int16(data, endian="little") 

57 

58 return CharacteristicExtendedPropertiesData( 

59 reliable_write=bool(value & ExtendedPropertiesFlags.RELIABLE_WRITE), 

60 writable_auxiliaries=bool(value & ExtendedPropertiesFlags.WRITABLE_AUXILIARIES), 

61 ) 

62 

63 def supports_reliable_write(self, data: bytes) -> bool: 

64 """Check if reliable write is supported.""" 

65 parsed = self._parse_descriptor_value(data) 

66 return parsed.reliable_write 

67 

68 def supports_writable_auxiliaries(self, data: bytes) -> bool: 

69 """Check if writable auxiliaries are supported.""" 

70 parsed = self._parse_descriptor_value(data) 

71 return parsed.writable_auxiliaries