| 1 | """An Python re-implementation of hierarchical module import.
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| 2 |
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| 3 | This code is intended to be read, not executed. However, it does work
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| 4 | -- all you need to do to enable it is "import knee".
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| 5 |
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| 6 | (The name is a pun on the klunkier predecessor of this module, "ni".)
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| 7 |
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| 8 | """
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| 9 |
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| 10 | import sys, imp, __builtin__
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| 11 |
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| 12 |
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| 13 | # Replacement for __import__()
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| 14 | def import_hook(name, globals=None, locals=None, fromlist=None):
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| 15 | parent = determine_parent(globals)
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| 16 | q, tail = find_head_package(parent, name)
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| 17 | m = load_tail(q, tail)
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| 18 | if not fromlist:
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| 19 | return q
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| 20 | if hasattr(m, "__path__"):
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| 21 | ensure_fromlist(m, fromlist)
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| 22 | return m
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| 23 |
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| 24 | def determine_parent(globals):
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| 25 | if not globals or not globals.has_key("__name__"):
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| 26 | return None
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| 27 | pname = globals['__name__']
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| 28 | if globals.has_key("__path__"):
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| 29 | parent = sys.modules[pname]
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| 30 | assert globals is parent.__dict__
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| 31 | return parent
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| 32 | if '.' in pname:
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| 33 | i = pname.rfind('.')
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| 34 | pname = pname[:i]
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| 35 | parent = sys.modules[pname]
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| 36 | assert parent.__name__ == pname
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| 37 | return parent
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| 38 | return None
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| 39 |
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| 40 | def find_head_package(parent, name):
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| 41 | if '.' in name:
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| 42 | i = name.find('.')
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| 43 | head = name[:i]
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| 44 | tail = name[i+1:]
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| 45 | else:
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| 46 | head = name
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| 47 | tail = ""
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| 48 | if parent:
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| 49 | qname = "%s.%s" % (parent.__name__, head)
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| 50 | else:
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| 51 | qname = head
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| 52 | q = import_module(head, qname, parent)
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| 53 | if q: return q, tail
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| 54 | if parent:
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| 55 | qname = head
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| 56 | parent = None
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| 57 | q = import_module(head, qname, parent)
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| 58 | if q: return q, tail
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| 59 | raise ImportError, "No module named " + qname
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| 60 |
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| 61 | def load_tail(q, tail):
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| 62 | m = q
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| 63 | while tail:
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| 64 | i = tail.find('.')
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| 65 | if i < 0: i = len(tail)
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| 66 | head, tail = tail[:i], tail[i+1:]
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