py: Allow subclass of native object to delegate to the native buffer_p.

Addresses issue #1109.
This commit is contained in:
Damien George 2015-02-09 15:08:00 +00:00
parent 1a6721fefd
commit 48244044a2
2 changed files with 39 additions and 1 deletions

View File

@ -666,6 +666,25 @@ STATIC mp_obj_t instance_getiter(mp_obj_t self_in) {
return mp_call_function_n_kw(meth, 0, 0, NULL);
}
STATIC mp_int_t instance_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
mp_obj_instance_t *self = self_in;
mp_obj_t member[2] = {MP_OBJ_NULL};
struct class_lookup_data lookup = {
.obj = self,
.attr = MP_QSTR_, // don't actually look for a method
.meth_offset = offsetof(mp_obj_type_t, buffer_p.get_buffer),
.dest = member,
.is_type = false,
};
mp_obj_class_lookup(&lookup, self->base.type);
if (member[0] == MP_OBJ_SENTINEL) {
mp_obj_type_t *type = mp_obj_get_type(self->subobj[0]);
return type->buffer_p.get_buffer(self->subobj[0], bufinfo, flags);
} else {
return 1; // object does not support buffer protocol
}
}
/******************************************************************************/
// type object
// - the struct is mp_obj_type_t and is defined in obj.h so const types can be made
@ -807,13 +826,16 @@ mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict)
o->name = name;
o->print = instance_print;
o->make_new = instance_make_new;
o->call = mp_obj_instance_call;
o->unary_op = instance_unary_op;
o->binary_op = instance_binary_op;
o->load_attr = mp_obj_instance_load_attr;
o->store_attr = mp_obj_instance_store_attr;
o->subscr = instance_subscr;
o->call = mp_obj_instance_call;
o->getiter = instance_getiter;
//o->iternext = ; not implemented
o->buffer_p.get_buffer = instance_get_buffer;
//o->stream_p = ; not implemented
o->bases_tuple = bases_tuple;
o->locals_dict = locals_dict;

View File

@ -0,0 +1,16 @@
# test when we subclass a type with the buffer protocol
class my_bytes(bytes):
pass
b1 = my_bytes([0, 1])
b2 = my_bytes([2, 3])
b3 = bytes([4, 5])
# addition will use the buffer protocol on the RHS
print(b1 + b2)
print(b1 + b3)
print(b3 + b1)
# bytearray construction will use the buffer protocol
print(bytearray(b1))