1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
import os
import logging
from olpc.datastore import layoutmanager
MAX_SIZE = 256
class MetadataStore(object):
def store(self, uid, metadata):
metadata = metadata.copy()
for key in metadata.keys():
if ' ' in key:
raise ValueError('Property names cannot include spaces. '
'Wrong name: %r' % key)
dir_path = layoutmanager.get_instance().get_entry_path(uid)
if not os.path.exists(dir_path):
os.makedirs(dir_path)
for key, value in metadata.items():
if isinstance(value, str) and \
(len(value) > MAX_SIZE or not self._is_unicode(value)):
self._write_external(key, value, dir_path)
del metadata[key]
metadata['uid'] = uid
self._encode(metadata, os.path.join(dir_path, 'metadata'))
def retrieve(self, uid, properties=None):
dir_path = layoutmanager.get_instance().get_entry_path(uid)
if not os.path.exists(dir_path):
raise ValueError('Unknown object: %r' % uid)
metadata_path = os.path.join(dir_path, 'metadata')
metadata = self._decode(metadata_path, properties)
if not properties or len(properties) != len(metadata):
extra_metadata_dir = os.path.join(dir_path, 'extra_metadata')
if os.path.exists(extra_metadata_dir):
for key in os.listdir(extra_metadata_dir):
if properties is not None and key not in properties:
continue
file_path = os.path.join(extra_metadata_dir, key)
if not os.path.exists(file_path):
# TODO: This class shouldn't know anything about dbus.
import dbus
metadata[key] = dbus.ByteArray(open(file_path).read())
return metadata
def delete(self, uid):
dir_path = layoutmanager.get_instance().get_entry_path(uid)
metadata_path = os.path.join(dir_path, 'metadata')
if os.path.isfile(metadata_path):
os.remove(os.path.join(dir_path, 'metadata'))
else:
logging.warning('%s is not a valid path' % metadata_path)
extra_metadata_path = os.path.join(dir_path, 'extra_metadata')
if os.path.isdir(extra_metadata_path):
for key in os.listdir(extra_metadata_path):
os.remove(os.path.join(extra_metadata_path, key))
os.rmdir(os.path.join(dir_path, 'extra_metadata'))
else:
logging.warning('%s is not a valid path' % extra_metadata_path)
def _write_external(self, key, value, dir_path):
extra_metadata_dir = os.path.join(dir_path, 'extra_metadata')
if not os.path.exists(extra_metadata_dir):
os.makedirs(extra_metadata_dir)
f = open(os.path.join(extra_metadata_dir, key), 'w')
f.write(value)
f.close()
def _is_unicode(self, string):
try:
string.decode('utf-8')
return True
except UnicodeDecodeError:
return False
def _encode(self, metadata, file_path):
f = open(file_path, 'w')
f.write('v1\n')
for key, value in metadata.items():
if not key:
raise ValueError('Property keys cannot be empty')
if (' ' in key) or ('\t' in key):
raise ValueError('Property keys cannot contain tabulators: %r' \
% key)
if value is None:
value = ''
else:
value = str(value)
f.write('%s\t%d\t%s\n' % (key, len(value), value))
f.close()
def _decode(self, file_path, properties):
f = open(file_path, 'r')
version_line = f.readline()
try:
version = int(version_line[1:-1])
if version != 1:
raise ValueError('Incompatible version %r' % version)
except:
logging.error('Invalid version line: %s' % version_line)
raise
metadata = {}
while True:
line = f.readline()
if not line:
break
key, value_len, value = line.split('\t', 2)
value_len = int(value_len)
if len(value) == value_len + 1:
value = value[:-1] # skip the newline
else:
value += f.read(value_len - len(value))
f.seek(1, 1) # skip the newline
if properties is None:
metadata[key] = value
elif key in properties:
metadata[key] = value
if len(properties) == len(metadata):
break
f.close()
return metadata
def _cast_for_journal(self, key, value):
# Hack because the current journal expects these properties to have some
# predefined types
if key in ['timestamp', 'keep']:
try:
return int(value)
except ValueError:
return value
else:
return value
|
