Restore CIRCUITPY-CHANGEs for stream protocols

We mark all protocols with their type using MP_PROTO_IMPLEMENT,
and checking in mp_get_stream{,_raise}.

This was not turning up as a problem in tests until a (new, not yet
commited) change to jpegio caused a segfault because a type implementing
a different protocol was passed in to mp_get_stream.

By using 0 (instead of MP_QSTR_protocol_stream) as the marker for
objects implementing the standard micropython stream protocol, the
number of CIRCUITPY-CHANGEs is minimized.

Author: jepler

extmod/modjson.c

@@ -188,7 +188,7 @@ STATIC mp_uint_t json_python_readinto(mp_obj_t obj, void *buf, mp_uint_t size, i
 }
 
 STATIC mp_obj_t _mod_json_load(mp_obj_t stream_obj, bool return_first_json) {
-    const mp_stream_p_t *stream_p = mp_proto_get(MP_QSTR_protocol_stream, stream_obj);
+    const mp_stream_p_t *stream_p = mp_proto_get(0, stream_obj);
     json_stream_t s;
     uint8_t character_buffer[CIRCUITPY_JSON_READ_CHUNK_SIZE];
     if (stream_p == NULL) {

ports/espressif/bindings/espnow/ESPNow.c

@@ -332,7 +332,6 @@ STATIC mp_uint_t espnow_stream_ioctl(mp_obj_t self_in, mp_uint_t request, uintpt
 }
 
 STATIC const mp_stream_p_t espnow_stream_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .ioctl = espnow_stream_ioctl,
 };
 

py/proto.h

@@ -27,6 +27,12 @@
 #ifndef MICROPY_INCLUDED_PY_PROTO_H
 #define MICROPY_INCLUDED_PY_PROTO_H
 
+// CIRCUITPY-CHANGE
+//
+// In CircuitPython, we have multiple different 'protocol' types (rather than multiplexing through ioctl).
+// The standard (read/write/ioctl) protocol is indicated by the "0" protocol, while others must MP_PROTO_IMPLEMENT(QSTR_...).
+// While not used in CircuitPython or tested, the ability to skip including the protocol field in a protocol object is included at the source level
+
 #ifdef MICROPY_UNSAFE_PROTO
 #define MP_PROTOCOL_HEAD /* NOTHING */
 #define MP_PROTO_IMPLEMENT(name) /* NOTHING */
@@ -35,7 +41,7 @@ static inline void *mp_proto_get(uint16_t name, mp_const_obj_type_t obj) {
 }
 #else
 #define MP_PROTOCOL_HEAD \
-    uint16_t name; // The name of this protocol, a qstr
+    uint16_t name;
 #define MP_PROTO_IMPLEMENT(n) .name = n,
 const void *mp_proto_get(uint16_t name, mp_const_obj_t obj);
 const void *mp_proto_get_or_throw(uint16_t name, mp_const_obj_t obj);

py/stream.c

@@ -83,14 +83,13 @@ mp_uint_t mp_stream_rw(mp_obj_t stream, void *buf_, mp_uint_t size, int *errcode
 }
 
 const mp_stream_p_t *mp_get_stream_raise(mp_obj_t self_in, int flags) {
-    const mp_obj_type_t *type = mp_obj_get_type(self_in);
-    if (MP_OBJ_TYPE_HAS_SLOT(type, protocol)) {
-        const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(type, protocol);
-        if (!((flags & MP_STREAM_OP_READ) && stream_p->read == NULL)
-            && !((flags & MP_STREAM_OP_WRITE) && stream_p->write == NULL)
-            && !((flags & MP_STREAM_OP_IOCTL) && stream_p->ioctl == NULL)) {
-            return stream_p;
-        }
+    // CIRCUITPY-CHANGE: using type-safe protocol accessor
+    const mp_stream_p_t *stream_p = mp_get_stream(self_in);
+    if (stream_p
+        && !((flags & MP_STREAM_OP_READ) && stream_p->read == NULL)
+        && !((flags & MP_STREAM_OP_WRITE) && stream_p->write == NULL)
+        && !((flags & MP_STREAM_OP_IOCTL) && stream_p->ioctl == NULL)) {
+        return stream_p;
     }
     // CPython: io.UnsupportedOperation, OSError subclass
     mp_raise_msg(&mp_type_OSError, MP_ERROR_TEXT("stream operation not supported"));

py/stream.h

@@ -103,7 +103,8 @@ MP_DECLARE_CONST_FUN_OBJ_VAR_BETWEEN(mp_stream_ioctl_obj);
 
 // Object is assumed to have a non-NULL stream protocol with valid r/w/ioctl methods
 static inline const mp_stream_p_t *mp_get_stream(mp_const_obj_t self) {
-    return (const mp_stream_p_t *)MP_OBJ_TYPE_GET_SLOT(((const mp_obj_base_t *)MP_OBJ_TO_PTR(self))->type, protocol);
+    // CIRCUITPY-CHANGE: using type-safe protocol accessor
+    return mp_proto_get(0, (mp_obj_t)self);
 }
 
 const mp_stream_p_t *mp_get_stream_raise(mp_obj_t self_in, int flags);

shared-bindings/_bleio/CharacteristicBuffer.c

@@ -212,7 +212,6 @@ STATIC const mp_rom_map_elem_t bleio_characteristic_buffer_locals_dict_table[] =
 STATIC MP_DEFINE_CONST_DICT(bleio_characteristic_buffer_locals_dict, bleio_characteristic_buffer_locals_dict_table);
 
 STATIC const mp_stream_p_t characteristic_buffer_stream_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = bleio_characteristic_buffer_read,
     .write = bleio_characteristic_buffer_write,
     .ioctl = bleio_characteristic_buffer_ioctl,

shared-bindings/busio/UART.c

@@ -453,7 +453,6 @@ STATIC MP_DEFINE_CONST_DICT(busio_uart_locals_dict, busio_uart_locals_dict_table
 
 #if CIRCUITPY_BUSIO_UART
 STATIC const mp_stream_p_t uart_stream_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = busio_uart_read,
     .write = busio_uart_write,
     .ioctl = busio_uart_ioctl,

shared-bindings/keypad/EventQueue.c

@@ -159,7 +159,6 @@ STATIC mp_uint_t eventqueue_ioctl(mp_obj_t self_in, mp_uint_t request, uintptr_t
 }
 
 STATIC const mp_stream_p_t eventqueue_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .ioctl = eventqueue_ioctl,
 };
 #endif

shared-bindings/socketpool/Socket.c

@@ -443,7 +443,6 @@ STATIC mp_uint_t socket_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint_t arg
 }
 
 STATIC const mp_stream_p_t socket_stream_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .ioctl = socket_ioctl,
     .is_text = false,
 };

shared-bindings/terminalio/Terminal.c

@@ -132,7 +132,6 @@ STATIC const mp_rom_map_elem_t terminalio_terminal_locals_dict_table[] = {
 STATIC MP_DEFINE_CONST_DICT(terminalio_terminal_locals_dict, terminalio_terminal_locals_dict_table);
 
 STATIC const mp_stream_p_t terminalio_terminal_stream_p = {
-    MP_PROTO_IMPLEMENT(MP_QSTR_protocol_stream)
     .read = NULL,
     .write = terminalio_terminal_write,
     .ioctl = terminalio_terminal_ioctl,