Mercurial > hgrepos > Python > libs > ConfigMix

comparison configmix/config.py @ 16:f85dc4677c01

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Implemented the real configuration dictionary with attribute access or variable substitution
author Franz Glasner <hg@dom66.de>
date Thu, 10 Mar 2016 09:39:35 +0100
parents
children 94b5e94fae44
comparison
equal deleted inserted replaced
15:0b1292e920af 16:f85dc4677c01
1 # -*- coding: utf-8 -*-
2 r"""The unified configuration dictionary with attribute support
3 or variable substitution.
4
5 """
6
7 from __future__ import division, absolute_import, print_function
8
9 try:
10 from collections import OrderedDict as ConfigurationBase
11 except ImportError:
12 try:
13 from ordereddict import OrderedDict as ConfigurationBase
14 except ImportError:
15 ConfigurationBase = dict
16
17 from .variables import lookup_varns, lookup_filter
18 from .compat import u
19
20
21 __all__ = ["Configuration"]
22
23
24 _MARKER = object()
25
26
27 class AttributeDict(ConfigurationBase):
28
29 def __getattr__(self, name):
30 try:
31 v = self[name]
32 except KeyError:
33 raise AttributeError("%s has no attribute %r" % (type(self), name))
34 else:
35 # Wrap a dict into another dict with attribute access support
36 if isinstance(v, dict):
37 return AttributeDict(v)
38 else:
39 return v
40
41
42 class Configuration(AttributeDict):
43
44 def getvar(self, varname, default=_MARKER):
45 """Get a variable of the form ``[[ns1.]ns2.]name`` - including
46 variables from other namespaces.
47
48 No variable expansion is done and no filters are applied.
49 """
50 varns, varname = self._split_ns(varname)
51 try:
52 if not varns:
53 lookupfn = self._lookupvar
54 else:
55 lookupfn = lookup_varns(varns)
56 varvalue = lookupfn(varname)
57 except KeyError:
58 if default is _MARKER:
59 raise KeyError("Variable %r not found" % varname)
60 else:
61 return default
62 else:
63 return varvalue
64
65 def getvar_s(self, varname, default=_MARKER):
66 """Get a variable - incliding variables from other namespaces.
67
68 Variables will be substituted recursively in the result.
69 """
70 try:
71 obj = self.getvar(varname)
72 return self.substitute_variables_in_obj(obj)
73 except KeyError:
74 if default is _MARKER:
75 raise
76 else:
77 return default
78
79 def _split_ns(self, s):
80 nameparts = s.split(':', 1)
81 if len(nameparts) == 1:
82 return (None, s, )
83 else:
84 return (nameparts[0], nameparts[1], )
85
86 def _split_filters(self, s):
87 nameparts = s.split('|')
88 if len(nameparts) == 1:
89 return (s, [], )
90 else:
91 return (nameparts[0].rstrip(), nameparts[1:], )
92
93 def _lookupvar(self, key, default=_MARKER):
94 """Lookup a variable.
95
96 If no default is given an unexisting `key` raises a `KeyError`
97 else `default` is returned.
98 """
99 parts = key.split('.')
100 try:
101 v = self[parts[0]]
102 for p in parts[1:]:
103 v = v[p]
104 except KeyError:
105 if default is _MARKER:
106 raise KeyError("Configuration variable %r not found" % key)
107 else:
108 return default
109 return v
110
111 # Speed
112 _TEXTTYPE = type(u(""))
113
114 def substitute_variables_in_obj(self, obj):
115 """Recursively expand variables in the object tree `obj`."""
116 if isinstance(obj, self._TEXTTYPE):
117 # a string - really replace the value
118 return self.expand_variable(obj)
119 elif isinstance(obj, list):
120 return [self.substitute_variables_in_obj(i) for i in obj]
121 elif isinstance(obj, tuple):
122 tmp = [self.substitute_variables_in_obj(i) for i in obj]
123 return type(obj)(tmp)
124 elif isinstance(obj, dict):
125 newdict = type(obj)()
126 for k in obj:
127 newdict[k] = self.substitute_variables_in_obj(obj[k])
128 return newdict
129 elif isinstance(obj, set):
130 newset = type(obj)()
131 for i in obj:
132 newset.add(self.substitute_variables_in_obj(i))
133 else:
134 return obj
135
136 # Speed
137 _STARTTOK = u(b"{{")
138 _ENDTOK = u(b"}}")
139
140 def expand_variable(self, s):
141 """Expand variables in a single string"""
142 start = s.find(self._STARTTOK, 0)
143 while start != -1:
144 end = s.find(self._ENDTOK, start)
145 if end < 0:
146 return s
147 varname, filters = self._split_filters(s[start+2:end])
148 varvalue = self._apply_filters(filters, self.getvar_s(varname))
149 s = u(b"{0}{1}{2}").format(s[:start], varvalue, s[end+2:])
150 # don't re-evaluate because `self.getvar_s()` expands already
151 start = s.find(self._STARTTOK, start + len(varvalue))
152 return s
153
154 def _apply_filters(self, filters, value):
155 for name in filters:
156 try:
157 filterfn = lookup_filter(name)
158 except KeyError:
159 raise NameError("Filter %r not found" % name)
160 else:
161 value = filterfn(self, value)
162 return value