Allow subclassing deque

Author: dhalbert

py/objdeque.c

@@ -46,6 +46,11 @@ static mp_obj_t mp_obj_deque_extend(mp_obj_t self_in, mp_obj_t arg_in);
 static mp_obj_t mp_obj_new_deque_it(mp_obj_t deque, mp_obj_iter_buf_t *iter_buf);
 #endif
 
+// CIRCUITPY-CHANGE
+static mp_obj_deque_t *native_deque(mp_obj_t self_in) {
+    return MP_OBJ_TO_PTR(mp_obj_cast_to_native_base(self_in, MP_OBJ_FROM_PTR(&mp_type_deque)));
+}
+
 static mp_obj_t deque_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
     mp_arg_check_num(n_args, n_kw, 2, 3, false);
 
@@ -79,7 +84,8 @@ static size_t deque_len(mp_obj_deque_t *self) {
 }
 
 static mp_obj_t deque_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
     switch (op) {
         case MP_UNARY_OP_BOOL:
             return mp_obj_new_bool(self->i_get != self->i_put);
@@ -98,7 +104,8 @@ static mp_obj_t deque_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
 }
 
 static mp_obj_t mp_obj_deque_append(mp_obj_t self_in, mp_obj_t arg) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
 
     size_t new_i_put = self->i_put + 1;
     if (new_i_put == self->alloc) {
@@ -123,7 +130,8 @@ static mp_obj_t mp_obj_deque_append(mp_obj_t self_in, mp_obj_t arg) {
 static MP_DEFINE_CONST_FUN_OBJ_2(deque_append_obj, mp_obj_deque_append);
 
 static mp_obj_t mp_obj_deque_appendleft(mp_obj_t self_in, mp_obj_t arg) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
 
     size_t new_i_get = self->i_get - 1;
     if (self->i_get == 0) {
@@ -162,7 +170,8 @@ static mp_obj_t mp_obj_deque_extend(mp_obj_t self_in, mp_obj_t arg_in) {
 static MP_DEFINE_CONST_FUN_OBJ_2(deque_extend_obj, mp_obj_deque_extend);
 
 static mp_obj_t deque_popleft(mp_obj_t self_in) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
 
     if (self->i_get == self->i_put) {
         mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("empty"));
@@ -180,7 +189,8 @@ static mp_obj_t deque_popleft(mp_obj_t self_in) {
 static MP_DEFINE_CONST_FUN_OBJ_1(deque_popleft_obj, deque_popleft);
 
 static mp_obj_t deque_pop(mp_obj_t self_in) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
 
     if (self->i_get == self->i_put) {
         mp_raise_msg(&mp_type_IndexError, MP_ERROR_TEXT("empty"));
@@ -205,7 +215,8 @@ static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
         // delete not supported, fall back to mp_obj_subscr() error message
         return MP_OBJ_NULL;
     }
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
 
     size_t offset = mp_get_index(self->base.type, deque_len(self), index, false);
     size_t index_val = self->i_get + offset;
@@ -226,7 +237,8 @@ static mp_obj_t deque_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
 
 #if 0
 static mp_obj_t deque_clear(mp_obj_t self_in) {
-    mp_obj_deque_t *self = MP_OBJ_TO_PTR(self_in);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *self = native_deque(self_in);
     self->i_get = self->i_put = 0;
     mp_seq_clear(self->items, 0, self->alloc, sizeof(*self->items));
     return mp_const_none;
@@ -286,7 +298,8 @@ typedef struct _mp_obj_deque_it_t {
 
 static mp_obj_t deque_it_iternext(mp_obj_t self_in) {
     mp_obj_deque_it_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_obj_deque_t *deque = MP_OBJ_TO_PTR(self->deque);
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *deque = native_deque(self->deque);
     if (self->cur != deque->i_put) {
         mp_obj_t o_out = deque->items[self->cur];
         if (++self->cur == deque->alloc) {
@@ -298,9 +311,10 @@ static mp_obj_t deque_it_iternext(mp_obj_t self_in) {
     }
 }
 
-static mp_obj_t mp_obj_new_deque_it(mp_obj_t deque, mp_obj_iter_buf_t *iter_buf) {
-    mp_obj_deque_t *deque_ = MP_OBJ_TO_PTR(deque);
-    size_t i_get = deque_->i_get;
+static mp_obj_t mp_obj_new_deque_it(mp_obj_t deque_in, mp_obj_iter_buf_t *iter_buf) {
+    // CIRCUITPY-CHANGE
+    mp_obj_deque_t *deque = native_deque(deque_in);
+    size_t i_get = deque->i_get;
     assert(sizeof(mp_obj_deque_it_t) <= sizeof(mp_obj_iter_buf_t));
     mp_obj_deque_it_t *o = (mp_obj_deque_it_t *)iter_buf;
     o->base.type = &mp_type_polymorph_iter;

tests/circuitpython/deque_subclass.py

@@ -0,0 +1,40 @@
+try:
+    from collections import deque
+except ImportError:
+    print("SKIP")
+    raise SystemExit
+
+
+class DequeSubclass(deque):
+    def __init__(self, values, maxlen):
+        super().__init__(values, maxlen)
+
+    def pop(self):
+        print("pop")
+        return super().pop()
+
+    def popleft(self):
+        print("popleft")
+        return super().popleft()
+
+    def append(self, value):
+        print("append")
+        return super().append(value)
+
+    def appendleft(self, value):
+        print("appendleft")
+        return super().appendleft(value)
+
+    def extend(self, value):
+        print("extend")
+        return super().extend(value)
+
+
+d = DequeSubclass([1, 2, 3], 10)
+print(d.append(4))
+print(d.appendleft(0))
+print(d.pop())
+print(d.popleft())
+d.extend([6, 7])
+# calling list() tests iteration.
+print(list(d))