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53e6db90 DC |
1 | import sys |
2 | import marshal | |
3 | import contextlib | |
4 | import dis | |
5 | ||
6 | from setuptools.extern.packaging import version | |
7 | ||
8 | from ._imp import find_module, PY_COMPILED, PY_FROZEN, PY_SOURCE | |
9 | from . import _imp | |
10 | ||
11 | ||
12 | __all__ = [ | |
13 | 'Require', 'find_module', 'get_module_constant', 'extract_constant' | |
14 | ] | |
15 | ||
16 | ||
17 | class Require: | |
18 | """A prerequisite to building or installing a distribution""" | |
19 | ||
20 | def __init__( | |
21 | self, name, requested_version, module, homepage='', | |
22 | attribute=None, format=None): | |
23 | ||
24 | if format is None and requested_version is not None: | |
25 | format = version.Version | |
26 | ||
27 | if format is not None: | |
28 | requested_version = format(requested_version) | |
29 | if attribute is None: | |
30 | attribute = '__version__' | |
31 | ||
32 | self.__dict__.update(locals()) | |
33 | del self.self | |
34 | ||
35 | def full_name(self): | |
36 | """Return full package/distribution name, w/version""" | |
37 | if self.requested_version is not None: | |
38 | return '%s-%s' % (self.name, self.requested_version) | |
39 | return self.name | |
40 | ||
41 | def version_ok(self, version): | |
42 | """Is 'version' sufficiently up-to-date?""" | |
43 | return self.attribute is None or self.format is None or \ | |
44 | str(version) != "unknown" and self.format(version) >= self.requested_version | |
45 | ||
46 | def get_version(self, paths=None, default="unknown"): | |
47 | """Get version number of installed module, 'None', or 'default' | |
48 | ||
49 | Search 'paths' for module. If not found, return 'None'. If found, | |
50 | return the extracted version attribute, or 'default' if no version | |
51 | attribute was specified, or the value cannot be determined without | |
52 | importing the module. The version is formatted according to the | |
53 | requirement's version format (if any), unless it is 'None' or the | |
54 | supplied 'default'. | |
55 | """ | |
56 | ||
57 | if self.attribute is None: | |
58 | try: | |
59 | f, p, i = find_module(self.module, paths) | |
60 | if f: | |
61 | f.close() | |
62 | return default | |
63 | except ImportError: | |
64 | return None | |
65 | ||
66 | v = get_module_constant(self.module, self.attribute, default, paths) | |
67 | ||
68 | if v is not None and v is not default and self.format is not None: | |
69 | return self.format(v) | |
70 | ||
71 | return v | |
72 | ||
73 | def is_present(self, paths=None): | |
74 | """Return true if dependency is present on 'paths'""" | |
75 | return self.get_version(paths) is not None | |
76 | ||
77 | def is_current(self, paths=None): | |
78 | """Return true if dependency is present and up-to-date on 'paths'""" | |
79 | version = self.get_version(paths) | |
80 | if version is None: | |
81 | return False | |
82 | return self.version_ok(str(version)) | |
83 | ||
84 | ||
85 | def maybe_close(f): | |
86 | @contextlib.contextmanager | |
87 | def empty(): | |
88 | yield | |
89 | return | |
90 | if not f: | |
91 | return empty() | |
92 | ||
93 | return contextlib.closing(f) | |
94 | ||
95 | ||
96 | def get_module_constant(module, symbol, default=-1, paths=None): | |
97 | """Find 'module' by searching 'paths', and extract 'symbol' | |
98 | ||
99 | Return 'None' if 'module' does not exist on 'paths', or it does not define | |
100 | 'symbol'. If the module defines 'symbol' as a constant, return the | |
101 | constant. Otherwise, return 'default'.""" | |
102 | ||
103 | try: | |
104 | f, path, (suffix, mode, kind) = info = find_module(module, paths) | |
105 | except ImportError: | |
106 | # Module doesn't exist | |
107 | return None | |
108 | ||
109 | with maybe_close(f): | |
110 | if kind == PY_COMPILED: | |
111 | f.read(8) # skip magic & date | |
112 | code = marshal.load(f) | |
113 | elif kind == PY_FROZEN: | |
114 | code = _imp.get_frozen_object(module, paths) | |
115 | elif kind == PY_SOURCE: | |
116 | code = compile(f.read(), path, 'exec') | |
117 | else: | |
118 | # Not something we can parse; we'll have to import it. :( | |
119 | imported = _imp.get_module(module, paths, info) | |
120 | return getattr(imported, symbol, None) | |
121 | ||
122 | return extract_constant(code, symbol, default) | |
123 | ||
124 | ||
125 | def extract_constant(code, symbol, default=-1): | |
126 | """Extract the constant value of 'symbol' from 'code' | |
127 | ||
128 | If the name 'symbol' is bound to a constant value by the Python code | |
129 | object 'code', return that value. If 'symbol' is bound to an expression, | |
130 | return 'default'. Otherwise, return 'None'. | |
131 | ||
132 | Return value is based on the first assignment to 'symbol'. 'symbol' must | |
133 | be a global, or at least a non-"fast" local in the code block. That is, | |
134 | only 'STORE_NAME' and 'STORE_GLOBAL' opcodes are checked, and 'symbol' | |
135 | must be present in 'code.co_names'. | |
136 | """ | |
137 | if symbol not in code.co_names: | |
138 | # name's not there, can't possibly be an assignment | |
139 | return None | |
140 | ||
141 | name_idx = list(code.co_names).index(symbol) | |
142 | ||
143 | STORE_NAME = 90 | |
144 | STORE_GLOBAL = 97 | |
145 | LOAD_CONST = 100 | |
146 | ||
147 | const = default | |
148 | ||
149 | for byte_code in dis.Bytecode(code): | |
150 | op = byte_code.opcode | |
151 | arg = byte_code.arg | |
152 | ||
153 | if op == LOAD_CONST: | |
154 | const = code.co_consts[arg] | |
155 | elif arg == name_idx and (op == STORE_NAME or op == STORE_GLOBAL): | |
156 | return const | |
157 | else: | |
158 | const = default | |
159 | ||
160 | ||
161 | def _update_globals(): | |
162 | """ | |
163 | Patch the globals to remove the objects not available on some platforms. | |
164 | ||
165 | XXX it'd be better to test assertions about bytecode instead. | |
166 | """ | |
167 | ||
168 | if not sys.platform.startswith('java') and sys.platform != 'cli': | |
169 | return | |
170 | incompatible = 'extract_constant', 'get_module_constant' | |
171 | for name in incompatible: | |
172 | del globals()[name] | |
173 | __all__.remove(name) | |
174 | ||
175 | ||
176 | _update_globals() |