stm: Implement mp_import_stat.

To follow up pull request #309.

stm/Makefile

@@ -49,6 +49,7 @@ SRC_C = \
 	pendsv.c \
 	gccollect.c \
 	lexerfatfs.c \
+	import.c \
 	pyexec.c \
 	led.c \
 	gpio.c \

stm/import.c

+#include <stdint.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "lexer.h"
+#include "ff.h"
+
+mp_import_stat_t mp_import_stat(const char *path) {
+    FILINFO fno;
+    FRESULT res = f_stat(path, &fno);
+    if (res == FR_OK) {
+        if ((fno.fattrib & AM_DIR) != 0) {
+            return MP_IMPORT_STAT_DIR;
+        } else {
+            return MP_IMPORT_STAT_FILE;
+        }
+    }
+    return MP_IMPORT_STAT_NO_EXIST;
+}

stm/lexerfatfs.c

@@ -51,8 +51,3 @@ mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
     fb->pos = 0;
     return mp_lexer_new(qstr_from_str(filename), fb, (mp_lexer_stream_next_char_t)file_buf_next_char, (mp_lexer_stream_close_t)file_buf_close);
 }
-
-mp_import_stat_t mp_import_stat(const char *path) {
-    // TODO implement me!
-    return MP_IMPORT_STAT_NO_EXIST;
-}