1 import imp

     2 import os

     3 import sys

     4 

     5 

     6 def module_has_submodule(package, module_name):

     7     """See if 'module' is in 'package'."""

     8     name = ".".join([package.__name__, module_name])

     9     if name in sys.modules:

    10         return True

    11     for finder in sys.meta_path:

    12         if finder.find_module(name):

    13             return True

    14     for entry in package.__path__:  # No __path__, then not a package.

    15         try:

    16             # Try the cached finder.

    17             finder = sys.path_importer_cache[entry]

    18             if finder is None:

    19                 # Implicit import machinery should be used.

    20                 try:

    21                     file_, _, _ = imp.find_module(module_name, [entry])

    22                     if file_:

    23                         file_.close()

    24                     return True

    25                 except ImportError:

    26                     continue

    27             # Else see if the finder knows of a loader.

    28             elif finder.find_module(name):

    29                 return True

    30             else:

    31                 continue

    32         except KeyError:

    33             # No cached finder, so try and make one.

    34             for hook in sys.path_hooks:

    35                 try:

    36                     finder = hook(entry)

    37                     # XXX Could cache in sys.path_importer_cache

    38                     if finder.find_module(name):

    39                         return True

    40                     else:

    41                         # Once a finder is found, stop the search.

    42                         break

    43                 except ImportError:

    44                     # Continue the search for a finder.

    45                     continue

    46             else:

    47                 # No finder found.

    48                 # Try the implicit import machinery if searching a directory.

    49                 if os.path.isdir(entry):

    50                     try:

    51                         file_, _, _ = imp.find_module(module_name, [entry])

    52                         if file_:

    53                             file_.close()

    54                         return True

    55                     except ImportError:

    56                         pass

    57                 # XXX Could insert None or NullImporter

    58     else:

    59         # Exhausted the search, so the module cannot be found.

    60         return False