--- /dev/null
+from __future__ import generators
+import sys, imp, marshal
+from imp import PKG_DIRECTORY, PY_COMPILED, PY_SOURCE, PY_FROZEN
+from distutils.version import StrictVersion, LooseVersion
+
+__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 _iter_code(code):
+
+ """Yield '(op,arg)' pair for each operation in code object 'code'"""
+
+ from array import array
+ from dis import HAVE_ARGUMENT, EXTENDED_ARG
+
+ bytes = array('b',code.co_code)
+ eof = len(code.co_code)
+
+ ptr = 0
+ extended_arg = 0
+
+ while ptr<eof:
+
+ op = bytes[ptr]
+
+ if op>=HAVE_ARGUMENT:
+
+ arg = bytes[ptr+1] + bytes[ptr+2]*256 + extended_arg
+ ptr += 3
+
+ if op==EXTENDED_ARG:
+ extended_arg = arg * 65536L
+ continue
+
+ else:
+ arg = None
+ ptr += 1
+
+ yield op,arg
+
+
+
+
+
+
+
+
+
+
+def find_module(module, paths=None):
+ """Just like 'imp.find_module()', but with package support"""
+
+ parts = module.split('.')
+
+ while parts:
+ part = parts.pop(0)
+ f, path, (suffix,mode,kind) = info = imp.find_module(part, paths)
+
+ if kind==PKG_DIRECTORY:
+ parts = parts or ['__init__']
+ paths = [path]
+
+ elif parts:
+ raise ImportError("Can't find %r in %s" % (parts,module))
+
+ return info
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+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) = find_module(module,paths)
+ except ImportError:
+ # Module doesn't exist
+ return None
+
+ try:
+ if kind==PY_COMPILED:
+ f.read(8) # skip magic & date
+ code = marshal.load(f)
+ elif kind==PY_FROZEN:
+ code = imp.get_frozen_object(module)
+ elif kind==PY_SOURCE:
+ code = compile(f.read(), path, 'exec')
+ else:
+ # Not something we can parse; we'll have to import it. :(
+ if module not in sys.modules:
+ imp.load_module(module,f,path,(suffix,mode,kind))
+ return getattr(sys.modules[module],symbol,None)
+
+ finally:
+ if f:
+ f.close()
+
+ 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 assigment
+ return None
+
+ name_idx = list(code.co_names).index(symbol)
+
+ STORE_NAME = 90
+ STORE_GLOBAL = 97
+ LOAD_CONST = 100
+
+ const = default
+
+ for op, arg in _iter_code(code):
+
+ 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
+
+if sys.platform.startswith('java') or sys.platform == 'cli':
+ # XXX it'd be better to test assertions about bytecode instead...
+ del extract_constant, get_module_constant
+ __all__.remove('extract_constant')
+ __all__.remove('get_module_constant')
+
+
projects / tahoe-lafs / zfec.git / blobdiff