Implement inquire_mechs_for_name in low-level API

This commit implements the inquire_mechs_for_name method
from RFC 2744, and adds a simple test as well.

Closes #10

gssapi/raw/misc.pyx

@@ -6,6 +6,7 @@ import six
 
 from gssapi.raw.cython_types cimport *
 from gssapi.raw.cython_converters cimport c_create_oid_list
+from gssapi.raw.names cimport Name
 from gssapi.raw.oids cimport OID
 
 from gssapi.raw.types import MechType
@@ -26,6 +27,10 @@ cdef extern from "gssapi.h":
                                          const gss_OID mech_type,
                                          gss_OID_set *name_types)
 
+    OM_uint32 gss_inquire_mechs_for_name(OM_uint32 *minor_status,
+                                         const gss_name_t input_name,
+                                         gss_OID_set *mech_types)
+
 
 def indicate_mechs():
     """
@@ -76,6 +81,35 @@ def inquire_names_for_mech(OID mech_type not None):
         raise GSSError(maj_stat, min_stat)
 
 
+def inquire_mechs_for_name(Name name not None):
+    """List the mechanisms which can process a name.
+
+    This method lists the mechanisms which may be able to
+    process the given name.
+
+    Args:
+        name (Name): the name in question
+
+    Returns:
+        list: the mechanism OIDs able to process the given name
+
+    Raises:
+        GSSError
+    """
+
+    cdef gss_OID_set mech_types
+
+    cdef OM_uint32 maj_stat, min_stat
+
+    maj_stat = gss_inquire_mechs_for_name(&min_stat, name.raw_name,
+                                          &mech_types)
+
+    if maj_stat == GSS_S_COMPLETE:
+        return c_create_oid_list(mech_types)
+    else:
+        raise GSSError(maj_stat, min_stat)
+
+
 def _display_status(unsigned int error_code, bint is_major_code,
                     OID mech_type=None, unsigned int message_context=0):
     """

gssapi/tests/test_raw.py

@@ -371,6 +371,15 @@ def test_inquire_names_for_mech(self):
         res.shouldnt_be_none()
         res.should_include(gb.NameType.kerberos_principal)
 
+    def test_inquire_mechs_for_name(self):
+        name = gb.import_name(self.USER_PRINC,
+                              gb.NameType.kerberos_principal)
+
+        res = gb.inquire_mechs_for_name(name)
+
+        res.shouldnt_be_none()
+        res.should_include(gb.MechType.kerberos)
+
 
 class TestIntEnumFlagSet(unittest.TestCase):
     def test_create_from_int(self):