| Guido van Rossum | 501d0bb | 1997-09-09 20:35:20 +0000 | [diff] [blame^] | 1 | # More structured (slower) alternative to mini |
| 2 | |
| 3 | import sys, imp, __builtin__, string |
| 4 | |
| 5 | |
| 6 | # Replacement for __import__() |
| 7 | def import_hook(name, globals=None, locals=None, fromlist=None): |
| 8 | parent = determine_parent(globals) |
| 9 | q, tail = find_head_package(parent, name) |
| 10 | m = load_tail(q, tail) |
| 11 | if not fromlist: |
| 12 | return q |
| 13 | if hasattr(m, "__path__"): |
| 14 | ensure_fromlist(m, fromlist) |
| 15 | return m |
| 16 | |
| 17 | def determine_parent(globals): |
| 18 | if not globals or not globals.has_key("__name__"): |
| 19 | return None |
| 20 | pname = globals['__name__'] |
| 21 | if globals.has_key("__path__"): |
| 22 | parent = sys.modules[pname] |
| 23 | assert globals is parent.__dict__ |
| 24 | return parent |
| 25 | if '.' in pname: |
| 26 | i = string.rfind(pname, '.') |
| 27 | pname = pname[:i] |
| 28 | parent = sys.modules[pname] |
| 29 | assert parent.__name__ == pname |
| 30 | return parent |
| 31 | return None |
| 32 | |
| 33 | def find_head_package(parent, name): |
| 34 | if '.' in name: |
| 35 | i = string.find(name, '.') |
| 36 | head = name[:i] |
| 37 | tail = name[i+1:] |
| 38 | else: |
| 39 | head = name |
| 40 | tail = "" |
| 41 | if parent: |
| 42 | qname = "%s.%s" % (parent.__name__, head) |
| 43 | else: |
| 44 | qname = head |
| 45 | q = import_module(head, qname, parent) |
| 46 | if q: return q, tail |
| 47 | if parent: |
| 48 | qname = head |
| 49 | parent = None |
| 50 | q = import_module(head, qname, parent) |
| 51 | if q: return q, tail |
| 52 | raise ImportError, "No module named " + qname |
| 53 | |
| 54 | def load_tail(q, tail): |
| 55 | m = q |
| 56 | while tail: |
| 57 | i = string.find(tail, '.') |
| 58 | if i < 0: i = len(tail) |
| 59 | head, tail = tail[:i], tail[i+1:] |
| 60 | mname = "%s.%s" % (m.__name__, head) |
| 61 | m = import_module(head, mname, m) |
| 62 | if not m: |
| 63 | raise ImportError, "No module named " + mname |
| 64 | return m |
| 65 | |
| 66 | def ensure_fromlist(m, fromlist): |
| 67 | for sub in fromlist: |
| 68 | if sub != "*" and not hasattr(m, sub): |
| 69 | subname = "%s.%s" % (m.__name__, sub) |
| 70 | submod = import_module(sub, subname, m) |
| 71 | ## if not submod: |
| 72 | ## raise ImportError, "No module named " + subname |
| 73 | |
| 74 | def import_module(partname, fqname, parent): |
| 75 | try: |
| 76 | return sys.modules[fqname] |
| 77 | except KeyError: |
| 78 | pass |
| 79 | try: |
| 80 | fp, pathname, stuff = imp.find_module(partname, |
| 81 | parent and parent.__path__) |
| 82 | except ImportError: |
| 83 | return None |
| 84 | try: |
| 85 | m = imp.load_module(fqname, fp, pathname, stuff) |
| 86 | finally: |
| 87 | if fp: fp.close() |
| 88 | if parent: |
| 89 | setattr(parent, partname, m) |
| 90 | return m |
| 91 | |
| 92 | |
| 93 | # Replacement for reload() |
| 94 | def reload_hook(module): |
| 95 | name = module.__name__ |
| 96 | if '.' not in name: |
| 97 | return import_module(name, name, None) |
| 98 | i = string.rfind(name, '.') |
| 99 | pname = name[:i] |
| 100 | parent = sys.modules[pname] |
| 101 | return import_module(name[i+1:], name, parent) |
| 102 | |
| 103 | |
| 104 | # Save the original hooks |
| 105 | original_import = __builtin__.__import__ |
| 106 | original_reload = __builtin__.reload |
| 107 | |
| 108 | # Now install our hooks |
| 109 | __builtin__.__import__ = import_hook |
| 110 | __builtin__.reload = reload_hook |
| 111 | |
| 112 | # pretend we're ni, too |
| 113 | sys.modules['ni'] = sys.modules[__name__] |
| 114 | def ni(): pass |
| 115 | def install(): pass |