stm32: Make default USB_VCP stream go through uos.dupterm for main REPL.

Use uos.dupterm for REPL configuration of the main USB_VCP(0) stream on
dupterm slot 1, if USB is enabled.  This means dupterm can also be used to
disable the boot REPL port if desired, via uos.dupterm(None, 1).

For efficiency this adds a simple hook to the global uos.dupterm code to
work with streams that are known to be native streams.

1 files changed, 25 insertions, 0 deletions

diff --git a/extmod/uos_dupterm.c b/extmod/uos_dupterm.c
index dec3e1a40..42cb21444 100644
--- a/extmod/uos_dupterm.c
+++ b/extmod/uos_dupterm.c
@@ -32,6 +32,7 @@
 #include "py/objtuple.h"
 #include "py/objarray.h"
 #include "py/stream.h"
+#include "extmod/misc.h"
 #include "lib/utils/interrupt_char.h"
 
 #if MICROPY_PY_OS_DUPTERM
@@ -58,6 +59,20 @@ int mp_uos_dupterm_rx_chr(void) {
             continue;
         }
 
+        #if MICROPY_PY_UOS_DUPTERM_BUILTIN_STREAM
+        if (mp_uos_dupterm_is_builtin_stream(MP_STATE_VM(dupterm_objs[idx]))) {
+            byte buf[1];
+            int errcode = 0;
+            const mp_stream_p_t *stream_p = mp_get_stream(MP_STATE_VM(dupterm_objs[idx]));
+            mp_uint_t out_sz = stream_p->read(MP_STATE_VM(dupterm_objs[idx]), buf, 1, &errcode);
+            if (errcode == 0 && out_sz != 0) {
+                return buf[0];
+             } else {
+                continue;
+             }
+        }
+        #endif
+
         nlr_buf_t nlr;
         if (nlr_push(&nlr) == 0) {
             byte buf[1];
@@ -98,6 +113,16 @@ void mp_uos_dupterm_tx_strn(const char *str, size_t len) {
         if (MP_STATE_VM(dupterm_objs[idx]) == MP_OBJ_NULL) {
             continue;
         }
+
+        #if MICROPY_PY_UOS_DUPTERM_BUILTIN_STREAM
+        if (mp_uos_dupterm_is_builtin_stream(MP_STATE_VM(dupterm_objs[idx]))) {
+            int errcode = 0;
+            const mp_stream_p_t *stream_p = mp_get_stream(MP_STATE_VM(dupterm_objs[idx]));
+            stream_p->write(MP_STATE_VM(dupterm_objs[idx]), str, len, &errcode);
+            continue;
+        }
+        #endif
+
         nlr_buf_t nlr;
         if (nlr_push(&nlr) == 0) {
             mp_stream_write(MP_STATE_VM(dupterm_objs[idx]), str, len, MP_STREAM_RW_WRITE);