##// END OF EJS Templates
demandimport: ignore resource module, not available under Windows.
Patrick Mezard -
r5098:0bbd86b8 default
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1 # demandimport.py - global demand-loading of modules for Mercurial
1 # demandimport.py - global demand-loading of modules for Mercurial
2 #
2 #
3 # Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>
3 # Copyright 2006, 2007 Matt Mackall <mpm@selenic.com>
4 #
4 #
5 # This software may be used and distributed according to the terms
5 # This software may be used and distributed according to the terms
6 # of the GNU General Public License, incorporated herein by reference.
6 # of the GNU General Public License, incorporated herein by reference.
7
7
8 '''
8 '''
9 demandimport - automatic demandloading of modules
9 demandimport - automatic demandloading of modules
10
10
11 To enable this module, do:
11 To enable this module, do:
12
12
13 import demandimport; demandimport.enable()
13 import demandimport; demandimport.enable()
14
14
15 Imports of the following forms will be demand-loaded:
15 Imports of the following forms will be demand-loaded:
16
16
17 import a, b.c
17 import a, b.c
18 import a.b as c
18 import a.b as c
19 from a import b,c # a will be loaded immediately
19 from a import b,c # a will be loaded immediately
20
20
21 These imports will not be delayed:
21 These imports will not be delayed:
22
22
23 from a import *
23 from a import *
24 b = __import__(a)
24 b = __import__(a)
25 '''
25 '''
26
26
27 _origimport = __import__
27 _origimport = __import__
28
28
29 class _demandmod(object):
29 class _demandmod(object):
30 """module demand-loader and proxy"""
30 """module demand-loader and proxy"""
31 def __init__(self, name, globals, locals):
31 def __init__(self, name, globals, locals):
32 if '.' in name:
32 if '.' in name:
33 head, rest = name.split('.', 1)
33 head, rest = name.split('.', 1)
34 after = [rest]
34 after = [rest]
35 else:
35 else:
36 head = name
36 head = name
37 after = []
37 after = []
38 object.__setattr__(self, "_data", (head, globals, locals, after))
38 object.__setattr__(self, "_data", (head, globals, locals, after))
39 object.__setattr__(self, "_module", None)
39 object.__setattr__(self, "_module", None)
40 def _extend(self, name):
40 def _extend(self, name):
41 """add to the list of submodules to load"""
41 """add to the list of submodules to load"""
42 self._data[3].append(name)
42 self._data[3].append(name)
43 def _load(self):
43 def _load(self):
44 if not self._module:
44 if not self._module:
45 head, globals, locals, after = self._data
45 head, globals, locals, after = self._data
46 mod = _origimport(head, globals, locals)
46 mod = _origimport(head, globals, locals)
47 # load submodules
47 # load submodules
48 def subload(mod, p):
48 def subload(mod, p):
49 h, t = p, None
49 h, t = p, None
50 if '.' in p:
50 if '.' in p:
51 h, t = p.split('.', 1)
51 h, t = p.split('.', 1)
52 if not hasattr(mod, h):
52 if not hasattr(mod, h):
53 setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
53 setattr(mod, h, _demandmod(p, mod.__dict__, mod.__dict__))
54 elif t:
54 elif t:
55 subload(getattr(mod, h), t)
55 subload(getattr(mod, h), t)
56
56
57 for x in after:
57 for x in after:
58 subload(mod, x)
58 subload(mod, x)
59
59
60 # are we in the locals dictionary still?
60 # are we in the locals dictionary still?
61 if locals and locals.get(head) == self:
61 if locals and locals.get(head) == self:
62 locals[head] = mod
62 locals[head] = mod
63 object.__setattr__(self, "_module", mod)
63 object.__setattr__(self, "_module", mod)
64
64
65 def __repr__(self):
65 def __repr__(self):
66 if self._module:
66 if self._module:
67 return "<proxied module '%s'>" % self._data[0]
67 return "<proxied module '%s'>" % self._data[0]
68 return "<unloaded module '%s'>" % self._data[0]
68 return "<unloaded module '%s'>" % self._data[0]
69 def __call__(self, *args, **kwargs):
69 def __call__(self, *args, **kwargs):
70 raise TypeError("'unloaded module' object is not callable")
70 raise TypeError("'unloaded module' object is not callable")
71 def __getattribute__(self, attr):
71 def __getattribute__(self, attr):
72 if attr in ('_data', '_extend', '_load', '_module'):
72 if attr in ('_data', '_extend', '_load', '_module'):
73 return object.__getattribute__(self, attr)
73 return object.__getattribute__(self, attr)
74 self._load()
74 self._load()
75 return getattr(self._module, attr)
75 return getattr(self._module, attr)
76 def __setattr__(self, attr, val):
76 def __setattr__(self, attr, val):
77 self._load()
77 self._load()
78 setattr(self._module, attr, val)
78 setattr(self._module, attr, val)
79
79
80 def _demandimport(name, globals=None, locals=None, fromlist=None):
80 def _demandimport(name, globals=None, locals=None, fromlist=None):
81 if not locals or name in ignore or fromlist == ('*',):
81 if not locals or name in ignore or fromlist == ('*',):
82 # these cases we can't really delay
82 # these cases we can't really delay
83 return _origimport(name, globals, locals, fromlist)
83 return _origimport(name, globals, locals, fromlist)
84 elif not fromlist:
84 elif not fromlist:
85 # import a [as b]
85 # import a [as b]
86 if '.' in name: # a.b
86 if '.' in name: # a.b
87 base, rest = name.split('.', 1)
87 base, rest = name.split('.', 1)
88 # email.__init__ loading email.mime
88 # email.__init__ loading email.mime
89 if globals and globals.get('__name__', None) == base:
89 if globals and globals.get('__name__', None) == base:
90 return _origimport(name, globals, locals, fromlist)
90 return _origimport(name, globals, locals, fromlist)
91 # if a is already demand-loaded, add b to its submodule list
91 # if a is already demand-loaded, add b to its submodule list
92 if base in locals:
92 if base in locals:
93 if isinstance(locals[base], _demandmod):
93 if isinstance(locals[base], _demandmod):
94 locals[base]._extend(rest)
94 locals[base]._extend(rest)
95 return locals[base]
95 return locals[base]
96 return _demandmod(name, globals, locals)
96 return _demandmod(name, globals, locals)
97 else:
97 else:
98 # from a import b,c,d
98 # from a import b,c,d
99 mod = _origimport(name, globals, locals)
99 mod = _origimport(name, globals, locals)
100 # recurse down the module chain
100 # recurse down the module chain
101 for comp in name.split('.')[1:]:
101 for comp in name.split('.')[1:]:
102 if not hasattr(mod, comp):
102 if not hasattr(mod, comp):
103 setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__))
103 setattr(mod, comp, _demandmod(comp, mod.__dict__, mod.__dict__))
104 mod = getattr(mod, comp)
104 mod = getattr(mod, comp)
105 for x in fromlist:
105 for x in fromlist:
106 # set requested submodules for demand load
106 # set requested submodules for demand load
107 if not(hasattr(mod, x)):
107 if not(hasattr(mod, x)):
108 setattr(mod, x, _demandmod(x, mod.__dict__, locals))
108 setattr(mod, x, _demandmod(x, mod.__dict__, locals))
109 return mod
109 return mod
110
110
111 ignore = ['_hashlib', '_xmlplus', 'fcntl', 'win32com.gen_py', 'pwd', 'grp']
111 ignore = [
112 '_hashlib',
113 '_xmlplus',
114 'fcntl',
115 'win32com.gen_py',
116 # imported by tarfile, not available under Windows
117 'pwd',
118 'grp',
119 # imported by profile, itself imported by hotshot.stats,
120 # not available under Windows
121 'resource',
122 ]
112
123
113 def enable():
124 def enable():
114 "enable global demand-loading of modules"
125 "enable global demand-loading of modules"
115 __builtins__["__import__"] = _demandimport
126 __builtins__["__import__"] = _demandimport
116
127
117 def disable():
128 def disable():
118 "disable global demand-loading of modules"
129 "disable global demand-loading of modules"
119 __builtins__["__import__"] = _origimport
130 __builtins__["__import__"] = _origimport
120
131
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