Coverage for src / bluetooth_sig / gatt / descriptors / cccd.py: 81%

1"""Client Characteristic Configuration 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 CCCDFlags(IntFlag): 

14 """CCCD (Client Characteristic Configuration Descriptor) flags.""" 

15 

16 NOTIFICATIONS_ENABLED = 0x0001 

17 INDICATIONS_ENABLED = 0x0002 

18 

19 

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

21 """CCCD (Client Characteristic Configuration Descriptor) data.""" 

22 

23 notifications_enabled: bool 

24 indications_enabled: bool 

25 

26 

27class CCCDDescriptor(BaseDescriptor): 

28 """Client Characteristic Configuration Descriptor (0x2902). 

29 

30 Controls notification and indication settings for a characteristic. 

31 Critical for enabling BLE notifications and indications. 

32 """ 

33 

34 _descriptor_name = "Client Characteristic Configuration" 

35 _writable = True # CCCD is always writable 

36 

37 def _has_structured_data(self) -> bool: 

38 return True 

39 

40 def _get_data_format(self) -> str: 

41 return "uint16" 

42 

43 def _parse_descriptor_value(self, data: bytes) -> CCCDData: 

44 """Parse CCCD value into notification/indication flags. 

45 

46 Args: 

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

48 

49 Returns: 

50 CCCDData with notification/indication flags 

51 

52 Raises: 

53 ValueError: If data is not exactly 2 bytes 

54 """ 

55 # Parse as little-endian uint16 

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

57 

58 return CCCDData( 

59 notifications_enabled=bool(value & CCCDFlags.NOTIFICATIONS_ENABLED), 

60 indications_enabled=bool(value & CCCDFlags.INDICATIONS_ENABLED), 

61 ) 

62 

63 @staticmethod 

64 def create_enable_notifications_value() -> bytes: 

65 """Create value to enable notifications.""" 

66 return CCCDFlags.NOTIFICATIONS_ENABLED.to_bytes(2, "little") 

67 

68 @staticmethod 

69 def create_enable_indications_value() -> bytes: 

70 """Create value to enable indications.""" 

71 return CCCDFlags.INDICATIONS_ENABLED.to_bytes(2, "little") 

72 

73 @staticmethod 

74 def create_enable_both_value() -> bytes: 

75 """Create value to enable both notifications and indications.""" 

76 return (CCCDFlags.NOTIFICATIONS_ENABLED | CCCDFlags.INDICATIONS_ENABLED).to_bytes(2, "little") 

77 

78 @staticmethod 

79 def create_disable_value() -> bytes: 

80 """Create value to disable notifications/indications.""" 

81 return (0).to_bytes(2, "little") 

82 

83 def is_notifications_enabled(self, data: bytes) -> bool: 

84 """Check if notifications are enabled.""" 

85 parsed = self._parse_descriptor_value(data) 

86 return parsed.notifications_enabled 

87 

88 def is_indications_enabled(self, data: bytes) -> bool: 

89 """Check if indications are enabled.""" 

90 parsed = self._parse_descriptor_value(data) 

91 return parsed.indications_enabled 

92 

93 def is_any_enabled(self, data: bytes) -> bool: 

94 """Check if either notifications or indications are enabled.""" 

95 parsed = self._parse_descriptor_value(data) 

96 return parsed.notifications_enabled or parsed.indications_enabled