JezK
Edit File: depends.py
import sys import marshal import contextlib from distutils.version import StrictVersion from .py33compat import Bytecode from .py27compat import find_module, PY_COMPILED, PY_FROZEN, PY_SOURCE from . import py27compat __all__ = [ 'Require', 'find_module', 'get_module_constant', 'extract_constant' ] class Require: """A prerequisite to building or installing a distribution""" def __init__( self, name, requested_version, module, homepage='', attribute=None, format=None): if format is None and requested_version is not None: format = StrictVersion if format is not None: requested_version = format(requested_version) if attribute is None: attribute = '__version__' self.__dict__.update(locals()) del self.self def full_name(self): """Return full package/distribution name, w/version""" if self.requested_version is not None: return '%s-%s' % (self.name, self.requested_version) return self.name def version_ok(self, version): """Is 'version' sufficiently up-to-date?""" return self.attribute is None or self.format is None or \ str(version) != "unknown" and version >= self.requested_version def get_version(self, paths=None, default="unknown"): """Get version number of installed module, 'None', or 'default' Search 'paths' for module. If not found, return 'None'. If found, return the extracted version attribute, or 'default' if no version attribute was specified, or the value cannot be determined without importing the module. The version is formatted according to the requirement's version format (if any), unless it is 'None' or the supplied 'default'. """ if self.attribute is None: try: f, p, i = find_module(self.module, paths) if f: f.close() return default except ImportError: return None v = get_module_constant(self.module, self.attribute, default, paths) if v is not None and v is not default and self.format is not None: return self.format(v) return v def is_present(self, paths=None): """Return true if dependency is present on 'paths'""" return self.get_version(paths) is not None def is_current(self, paths=None): """Return true if dependency is present and up-to-date on 'paths'""" version = self.get_version(paths) if version is None: return False return self.version_ok(version) def maybe_close(f): @contextlib.contextmanager def empty(): yield return if not f: return empty() return contextlib.closing(f) def get_module_constant(module, symbol, default=-1, paths=None): """Find 'module' by searching 'paths', and extract 'symbol' Return 'None' if 'module' does not exist on 'paths', or it does not define 'symbol'. If the module defines 'symbol' as a constant, return the constant. Otherwise, return 'default'.""" try: f, path, (suffix, mode, kind) = info = find_module(module, paths) except ImportError: # Module doesn't exist return None with maybe_close(f): if kind == PY_COMPILED: f.read(8) # skip magic & date code = marshal.load(f) elif kind == PY_FROZEN: code = py27compat.get_frozen_object(module, paths) elif kind == PY_SOURCE: code = compile(f.read(), path, 'exec') else: # Not something we can parse; we'll have to import it. :( imported = py27compat.get_module(module, paths, info) return getattr(imported, symbol, None) return extract_constant(code, symbol, default) def extract_constant(code, symbol, default=-1): """Extract the constant value of 'symbol' from 'code' If the name 'symbol' is bound to a constant value by the Python code object 'code', return that value. If 'symbol' is bound to an expression, return 'default'. Otherwise, return 'None'. Return value is based on the first assignment to 'symbol'. 'symbol' must be a global, or at least a non-"fast" local in the code block. That is, only 'STORE_NAME' and 'STORE_GLOBAL' opcodes are checked, and 'symbol' must be present in 'code.co_names'. """ if symbol not in code.co_names: # name's not there, can't possibly be an assignment return None name_idx = list(code.co_names).index(symbol) STORE_NAME = 90 STORE_GLOBAL = 97 LOAD_CONST = 100 const = default for byte_code in Bytecode(code): op = byte_code.opcode arg = byte_code.arg if op == LOAD_CONST: const = code.co_consts[arg] elif arg == name_idx and (op == STORE_NAME or op == STORE_GLOBAL): return const else: const = default def _update_globals(): """ Patch the globals to remove the objects not available on some platforms. XXX it'd be better to test assertions about bytecode instead. """ if not sys.platform.startswith('java') and sys.platform != 'cli': return incompatible = 'extract_constant', 'get_module_constant' for name in incompatible: del globals()[name] __all__.remove(name) _update_globals()