Coverage for src / bluetooth_sig / gatt / descriptors / characteristic_extended_properties.py: 79%

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 ..constants import SIZE_UINT16 

11from .base import BaseDescriptor 

12 

13 

14class ExtendedPropertiesFlags(IntFlag): 

15 """Characteristic Extended Properties flags.""" 

16 

17 RELIABLE_WRITE = 0x0001 

18 WRITABLE_AUXILIARIES = 0x0002 

19 

20 

21class CharacteristicExtendedPropertiesData(msgspec.Struct, frozen=True, kw_only=True): 

22 """Characteristic Extended Properties descriptor data.""" 

23 

24 reliable_write: bool 

25 writable_auxiliaries: bool 

26 

27 

28class CharacteristicExtendedPropertiesDescriptor(BaseDescriptor): 

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

30 

31 Defines extended properties for a characteristic using bit flags. 

32 Indicates support for reliable writes and writable auxiliaries. 

33 """ 

34 

35 def _has_structured_data(self) -> bool: 

36 return True 

37 

38 def _get_data_format(self) -> str: 

39 return "uint16" 

40 

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

42 """Parse Characteristic Extended Properties value. 

43 

44 Args: 

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

46 

47 Returns: 

48 CharacteristicExtendedPropertiesData with property flags 

49 

50 Raises: 

51 ValueError: If data is not exactly 2 bytes 

52 """ 

53 if len(data) != SIZE_UINT16: 

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

55 

56 # Parse as little-endian uint16 

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

58 

59 return CharacteristicExtendedPropertiesData( 

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

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

62 ) 

63 

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

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

66 parsed = self._parse_descriptor_value(data) 

67 return parsed.reliable_write 

68 

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

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

71 parsed = self._parse_descriptor_value(data) 

72 return parsed.writable_auxiliaries