evdev module-----util.py 

 1 # encoding: utf-8
 2 
 3 import os
 4 import stat
 5 import glob
 6 
 7 from evdev import ecodes
 8 from evdev.events import event_factory
 9 
10 
11 def list_devices(input_device_dir='/dev/input'):
12     '''List readable character devices.'''
13 
14     fns = glob.glob('{0}/event*'.format(input_device_dir))
15     fns = list(filter(is_device, fns))
16 
17     return fns
18 
19 
20 def is_device(fn):
21     '''Determine if a file exists, is readable and is a character device.'''
22 
23     if not os.path.exists(fn):
24         return False
25 
26     m = os.stat(fn)[stat.ST_MODE]
27     if not stat.S_ISCHR(m):
28         return False
29 
30     if not os.access(fn, os.R_OK):
31         return False
32 
33     return True
34 
35 
36 def categorize(event):
37     '''
38     Categorize an event according to its type.
39 
40     The :data:`event_factory <evdev.events.event_factory>` dictionary maps
41     event types to their classes. If there is no corresponding key, the event
42     is returned as it was.
43     '''
44 
45     if event.type in event_factory:
46         return event_factory[event.type](event)
47     else:
48         return event
49 
50 
51 def resolve_ecodes(typecodemap, unknown='?'):
52     '''
53     Resolve event codes and types to their verbose names.
54 
55     :param typecodemap: mapping of event types to lists of event codes
56     :param unknown: symbol to which unknown types or codes will be resolved
57 
58     Example::
59 
60         resolve_ecodes({ 1 : [272, 273, 274] })
61         { ('EV_KEY', 1) : [('BTN_MOUSE', 272), ('BTN_RIGHT', 273), ('BTN_MIDDLE', 274)] }
62 
63     If the typecodemap contains absolute axis info (wrapped in
64     instances of `AbsInfo <evdev.device.AbsInfo>`) the result would
65     look like::
66 
67         resove_ecodes({ 3 : [(0, AbsInfo(...))] })
68         { ('EV_ABS', 3L): [(('ABS_X', 0L), AbsInfo(...))] }
69     '''
70 
71     for etype, codes in typecodemap.items():
72         type_name = ecodes.EV[etype]
73 
74         # ecodes.keys are a combination of KEY_ and BTN_ codes
75         if etype == ecodes.EV_KEY:
76             code_names = ecodes.keys
77         else:
78             code_names = getattr(ecodes, type_name.split('_')[-1])
79 
80         res = []
81         for i in codes:
82             # elements with AbsInfo(), eg { 3 : [(0, AbsInfo(...)), (1, AbsInfo(...))] }
83             if isinstance(i, tuple):
84                 l = ((code_names[i[0]], i[0]), i[1]) if i[0] in code_names \
85                     else ((unknown, i[0]), i[1])
86 
87             # just ecodes { 0 : [0, 1, 3], 1 : [30, 48] }
88             else:
89                 l = (code_names[i], i) if i in code_names else (unknown, i)
90 
91             res.append(l)
92 
93         yield (type_name, etype), res
94 
95 
96 __all__ = list_devices, is_device, categorize, resolve_ecodes

 

posted @ 2016-07-13 10:01  碧水东流至此回  阅读(257)  评论(0)    收藏  举报