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126 lines
3 KiB
Python
126 lines
3 KiB
Python
"""An Python re-implementation of hierarchical module import.
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This code is intended to be read, not executed. However, it does work
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-- all you need to do to enable it is "import knee".
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(The name is a pun on the klunkier predecessor of this module, "ni".)
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"""
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import sys, imp, __builtin__, string
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# Replacement for __import__()
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def import_hook(name, globals=None, locals=None, fromlist=None):
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parent = determine_parent(globals)
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q, tail = find_head_package(parent, name)
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m = load_tail(q, tail)
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if not fromlist:
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return q
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if hasattr(m, "__path__"):
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ensure_fromlist(m, fromlist)
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return m
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def determine_parent(globals):
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if not globals or not globals.has_key("__name__"):
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return None
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pname = globals['__name__']
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if globals.has_key("__path__"):
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parent = sys.modules[pname]
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assert globals is parent.__dict__
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return parent
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if '.' in pname:
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i = string.rfind(pname, '.')
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pname = pname[:i]
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parent = sys.modules[pname]
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assert parent.__name__ == pname
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return parent
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return None
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def find_head_package(parent, name):
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if '.' in name:
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i = string.find(name, '.')
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head = name[:i]
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tail = name[i+1:]
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else:
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head = name
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tail = ""
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if parent:
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qname = "%s.%s" % (parent.__name__, head)
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else:
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qname = head
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q = import_module(head, qname, parent)
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if q: return q, tail
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if parent:
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qname = head
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parent = None
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q = import_module(head, qname, parent)
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if q: return q, tail
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raise ImportError, "No module named " + qname
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def load_tail(q, tail):
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m = q
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while tail:
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i = string.find(tail, '.')
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if i < 0: i = len(tail)
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head, tail = tail[:i], tail[i+1:]
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mname = "%s.%s" % (m.__name__, head)
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m = import_module(head, mname, m)
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if not m:
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raise ImportError, "No module named " + mname
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return m
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def ensure_fromlist(m, fromlist, recursive=0):
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for sub in fromlist:
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if sub == "*":
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if not recursive:
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try:
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all = m.__all__
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except AttributeError:
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pass
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else:
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ensure_fromlist(m, all, 1)
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continue
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if sub != "*" and not hasattr(m, sub):
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subname = "%s.%s" % (m.__name__, sub)
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submod = import_module(sub, subname, m)
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if not submod:
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raise ImportError, "No module named " + subname
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def import_module(partname, fqname, parent):
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try:
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return sys.modules[fqname]
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except KeyError:
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pass
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try:
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fp, pathname, stuff = imp.find_module(partname,
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parent and parent.__path__)
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except ImportError:
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return None
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try:
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m = imp.load_module(fqname, fp, pathname, stuff)
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finally:
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if fp: fp.close()
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if parent:
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setattr(parent, partname, m)
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return m
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# Replacement for reload()
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def reload_hook(module):
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name = module.__name__
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if '.' not in name:
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return import_module(name, name, None)
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i = string.rfind(name, '.')
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pname = name[:i]
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parent = sys.modules[pname]
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return import_module(name[i+1:], name, parent)
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# Save the original hooks
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original_import = __builtin__.__import__
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original_reload = __builtin__.reload
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# Now install our hooks
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__builtin__.__import__ = import_hook
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__builtin__.reload = reload_hook
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