pybricks.messaging: Implement rfcomm_scan skeleton.

This allocates data for the async rfcomm_scan results, and returns a list of dictionaries. Doesn't do any scanning yet.

Co-authored-by: James Aguilar <[email protected]>

Author: laurensvalk

lib/pbio/include/pbdrv/bluetooth.h

@@ -553,6 +553,14 @@ pbio_error_t pbdrv_bluetooth_await_advertise_or_scan_command(pbio_os_state_t *st
  */
 pbio_error_t pbdrv_bluetooth_close_user_tasks(pbio_os_state_t *state, pbio_os_timer_t *timer);
 
+// A single result from an inquiry scan.
+typedef struct {
+    uint8_t bdaddr[6];
+    int8_t rssi;
+    char name[249];
+    uint32_t class_of_device;
+} pbdrv_bluetooth_inquiry_result_t;
+
 #else // PBDRV_CONFIG_BLUETOOTH
 
 static inline void pbdrv_bluetooth_init(void) {

pybricks/messaging/pb_module_messaging.c

@@ -5,21 +5,150 @@
 
 #if PYBRICKS_PY_MESSAGING
 
+#include <stdio.h>
+#include <string.h>
+
 #include "py/mphal.h"
 #include "py/obj.h"
 #include "py/objstr.h"
 #include "py/runtime.h"
 #include "py/mperrno.h"
 
+#include <pbdrv/bluetooth.h>
+
+#include <pbio/int_math.h>
 #include <pbio/util.h>
 
 #include <pybricks/util_mp/pb_obj_helper.h>
 #include <pybricks/util_mp/pb_kwarg_helper.h>
 
 #include <pybricks/util_pb/pb_error.h>
+#include <pybricks/tools/pb_type_async.h>
+
+#define DEBUG 0
+
+#if DEBUG
+#include <pbio/debug.h>
+#define DEBUG_PRINT pbio_debug
+#else
+#define DEBUG_PRINT(...)
+#endif
+
+typedef struct {
+    mp_obj_base_t base;
+    uint32_t num_results;
+    uint32_t num_results_max;
+    uint32_t num_results_printed;
+    pbdrv_bluetooth_inquiry_result_t results[];
+} pb_messaging_rfcomm_scan_result_obj_t;
+
+static mp_obj_t pb_messaging_rfcomm_scan_close(mp_obj_t self_in) {
+    pb_messaging_rfcomm_scan_result_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    DEBUG_PRINT("rfcomm scan data freed\n");
+    self->num_results_max = 0;
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(pb_messaging_rfcomm_scan_close_obj, pb_messaging_rfcomm_scan_close);
+
+static const mp_rom_map_elem_t pb_messaging_rfcomm_scan_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&pb_messaging_rfcomm_scan_close_obj) },
+};
+static MP_DEFINE_CONST_DICT(pb_messaging_rfcomm_scan_locals_dict, pb_messaging_rfcomm_scan_locals_dict_table);
+
+MP_DEFINE_CONST_OBJ_TYPE(pb_type_messaging_rfcomm_scan, MP_QSTR_rfcomm_scan, MP_TYPE_FLAG_NONE, locals_dict, &pb_messaging_rfcomm_scan_locals_dict);
+
+/**
+ * Utility for converting a bluetooth address byte buffer to a string.
+ *
+ * The result does not persist. Intended for instant consumption.
+ *
+ * @param  [in]  address 6-byte bluetooth address.
+ * @return               Formatted bluetooth address string.
+ */
+static char *format_bluetooth_address(uint8_t *address) {
+    static char bdaddr_str[18];
+    snprintf(bdaddr_str, sizeof(bdaddr_str), "%02X:%02X:%02X:%02X:%02X:%02X",
+        address[0], address[1], address[2], address[3], address[4], address[5]);
+    return bdaddr_str;
+}
+
+/**
+ * Wrapper around the actual driver task that prints progress as we go along
+ * if the verbose option was specified.
+ */
+static pbio_error_t pb_messaging_rfcomm_scan_thread(pbio_os_state_t *state, mp_obj_t parent_obj) {
+
+    pb_messaging_rfcomm_scan_result_obj_t *scanner = MP_OBJ_TO_PTR(parent_obj);
+
+    while (scanner->num_results_printed < scanner->num_results) {
+        pbdrv_bluetooth_inquiry_result_t *result = &scanner->results[scanner->num_results_printed++];
+        mp_printf(&mp_plat_print, "Detected %s: %s with class %d and RSSI %d.\n",
+            format_bluetooth_address(result->bdaddr), result->name, result->class_of_device, result->rssi);
+    }
+
+    return PBIO_SUCCESS;
+}
+
+/**
+ * Maps the inquiry results to a list of dictionary, to be returned to the user.
+ */
+static mp_obj_t pb_messaging_rfcomm_scan_return_map(mp_obj_t parent_obj) {
+
+    pb_messaging_rfcomm_scan_result_obj_t *scanner = MP_OBJ_TO_PTR(parent_obj);
+
+    mp_obj_t list = mp_obj_new_list(0, NULL);
+
+    for (uint32_t i = 0; i < scanner->num_results; i++) {
+        mp_obj_t dict = mp_obj_new_dict(0);
+        pbdrv_bluetooth_inquiry_result_t *result = &scanner->results[i];
+        mp_obj_dict_store(dict, MP_ROM_QSTR(MP_QSTR_address), mp_obj_new_str(format_bluetooth_address(result->bdaddr), 17));
+        mp_obj_dict_store(dict, MP_ROM_QSTR(MP_QSTR_name), mp_obj_new_str(result->name, strlen(result->name)));
+        mp_obj_dict_store(dict, MP_ROM_QSTR(MP_QSTR_rssi), mp_obj_new_int(result->rssi));
+        mp_obj_dict_store(dict, MP_ROM_QSTR(MP_QSTR_class), mp_obj_new_int(result->class_of_device));
+        mp_obj_list_append(list, dict);
+    }
+    return list;
+}
+
+// pybricks.messaging.rfcomm_scan
+static mp_obj_t pb_messaging_rfcomm_scan(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    PB_PARSE_ARGS_FUNCTION(n_args, pos_args, kw_args,
+        PB_ARG_DEFAULT_INT(timeout, 10000),
+        PB_ARG_DEFAULT_INT(num_results, 5),
+        PB_ARG_DEFAULT_TRUE(verbose)
+        );
+
+    // Allocate the maximum number of expected results.
+    uint32_t num_results_max = mp_obj_get_int(num_results_in);
+    if (!num_results_max) {
+        num_results_max = 1;
+    }
+    pb_messaging_rfcomm_scan_result_obj_t *scanner = mp_obj_malloc_var_with_finaliser(
+        pb_messaging_rfcomm_scan_result_obj_t, pbdrv_bluetooth_inquiry_result_t,
+        num_results_max, &pb_type_messaging_rfcomm_scan);
+
+    // Initialize at zero results.
+    scanner->num_results = 0;
+    scanner->num_results_max = mp_obj_get_int(num_results_in);
+    scanner->num_results_printed = mp_obj_is_true(verbose_in) ? 0 : scanner->num_results_max;
+    (void)timeout_in;
+
+    // Create an awaitable with a reference to our result to keep it from being
+    // garbage collected.
+    pb_type_async_t *iter = NULL;
+    pb_type_async_t config = {
+        .iter_once = pb_messaging_rfcomm_scan_thread,
+        .parent_obj = MP_OBJ_FROM_PTR(scanner),
+        .return_map = pb_messaging_rfcomm_scan_return_map,
+    };
+    return pb_type_async_wait_or_await(&config, &iter, false);
+}
+// See also messaging_globals_table below. This function object is added there to make it importable.
+static MP_DEFINE_CONST_FUN_OBJ_KW(pb_messaging_rfcomm_scan_obj, 0, pb_messaging_rfcomm_scan);
 
 static const mp_rom_map_elem_t messaging_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_messaging) },
+    { MP_ROM_QSTR(MP_QSTR_rfcomm_scan), MP_ROM_PTR(&pb_messaging_rfcomm_scan_obj) },
 };
 static MP_DEFINE_CONST_DICT(pb_module_messaging_globals, messaging_globals_table);