py: Overhaul and simplify printf/pfenv mechanism.

Previous to this patch the printing mechanism was a bit of a tangled
mess.  This patch attempts to consolidate printing into one interface.

All (non-debug) printing now uses the mp_print* family of functions,
mainly mp_printf.  All these functions take an mp_print_t structure as
their first argument, and this structure defines the printing backend
through the "print_strn" function of said structure.

Printing from the uPy core can reach the platform-defined print code via
two paths: either through mp_sys_stdout_obj (defined pert port) in
conjunction with mp_stream_write; or through the mp_plat_print structure
which uses the MP_PLAT_PRINT_STRN macro to define how string are printed
on the platform.  The former is only used when MICROPY_PY_IO is defined.

With this new scheme printing is generally more efficient (less layers
to go through, less arguments to pass), and, given an mp_print_t*
structure, one can call mp_print_str for efficiency instead of
mp_printf("%s", ...).  Code size is also reduced by around 200 bytes on
Thumb2 archs.

5 files changed, 15 insertions, 14 deletions

diff --git a/unix/file.c b/unix/file.c
index 6688028a4..dfe2d6e11 100644
--- a/unix/file.c
+++ b/unix/file.c
@@ -60,10 +60,10 @@ STATIC void check_fd_is_open(const mp_obj_fdfile_t *o) {
 extern const mp_obj_type_t mp_type_fileio;
 extern const mp_obj_type_t mp_type_textio;
 
-STATIC void fdfile_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void fdfile_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_fdfile_t *self = self_in;
-    print(env, "<io.%s %d>", mp_obj_get_type_str(self), self->fd);
+    mp_printf(print, "<io.%s %d>", mp_obj_get_type_str(self), self->fd);
 }
 
 STATIC mp_uint_t fdfile_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
diff --git a/unix/main.c b/unix/main.c
index 02809d89b..4729b63f6 100644
--- a/unix/main.c
+++ b/unix/main.c
@@ -43,7 +43,6 @@
 #include "py/repl.h"
 #include "py/gc.h"
 #include "py/stackctrl.h"
-#include "py/pfenv.h"
 #include "genhdr/py-version.h"
 #include "input.h"
 
@@ -91,7 +90,7 @@ STATIC int handle_uncaught_exception(mp_obj_t exc) {
     }
 
     // Report all other exceptions
-    mp_obj_print_exception(printf_wrapper, NULL, exc);
+    mp_obj_print_exception(&mp_plat_print, exc);
     return 1;
 }
 
diff --git a/unix/modffi.c b/unix/modffi.c
index b3dbaa050..9e81b1e33 100644
--- a/unix/modffi.c
+++ b/unix/modffi.c
@@ -167,10 +167,10 @@ STATIC mp_obj_t return_ffi_value(ffi_arg val, char type)
 
 // FFI module
 
-STATIC void ffimod_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void ffimod_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_ffimod_t *self = self_in;
-    print(env, "<ffimod %p>", self->handle);
+    mp_printf(print, "<ffimod %p>", self->handle);
 }
 
 STATIC mp_obj_t ffimod_close(mp_obj_t self_in) {
@@ -338,10 +338,10 @@ STATIC const mp_obj_type_t ffimod_type = {
 
 // FFI function
 
-STATIC void ffifunc_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void ffifunc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_ffifunc_t *self = self_in;
-    print(env, "<ffifunc %p>", self->func);
+    mp_printf(print, "<ffifunc %p>", self->func);
 }
 
 STATIC mp_obj_t ffifunc_call(mp_obj_t self_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args) {
@@ -410,10 +410,10 @@ STATIC const mp_obj_type_t ffifunc_type = {
 
 // FFI callback for Python function
 
-STATIC void fficallback_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void fficallback_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_fficallback_t *self = self_in;
-    print(env, "<fficallback %p>", self->func);
+    mp_printf(print, "<fficallback %p>", self->func);
 }
 
 STATIC const mp_obj_type_t fficallback_type = {
@@ -424,11 +424,11 @@ STATIC const mp_obj_type_t fficallback_type = {
 
 // FFI variable
 
-STATIC void ffivar_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void ffivar_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_ffivar_t *self = self_in;
     // Variable value printed as cast to int
-    print(env, "<ffivar @%p: 0x%x>", self->var, *(int*)self->var);
+    mp_printf(print, "<ffivar @%p: 0x%x>", self->var, *(int*)self->var);
 }
 
 STATIC mp_obj_t ffivar_get(mp_obj_t self_in) {
diff --git a/unix/modsocket.c b/unix/modsocket.c
index 8f6ac26c6..738581a0a 100644
--- a/unix/modsocket.c
+++ b/unix/modsocket.c
@@ -82,10 +82,10 @@ STATIC mp_obj_socket_t *socket_new(int fd) {
 }
 
 
-STATIC void socket_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+STATIC void socket_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
     (void)kind;
     mp_obj_socket_t *self = self_in;
-    print(env, "<_socket %d>", self->fd);
+    mp_printf(print, "<_socket %d>", self->fd);
 }
 
 STATIC mp_uint_t socket_read(mp_obj_t o_in, void *buf, mp_uint_t size, int *errcode) {
diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index 00cb12139..694db88fc 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -170,6 +170,8 @@ void mp_unix_mark_exec(void);
 #define MP_PLAT_ALLOC_EXEC(min_size, ptr, size) mp_unix_alloc_exec(min_size, ptr, size)
 #define MP_PLAT_FREE_EXEC(ptr, size) mp_unix_free_exec(ptr, size)
 
+#define MP_PLAT_PRINT_STRN(str, len) fwrite(str, 1, len, stdout)
+
 extern const struct _mp_obj_fun_builtin_t mp_builtin_input_obj;
 extern const struct _mp_obj_fun_builtin_t mp_builtin_open_obj;
 #define MICROPY_PORT_BUILTINS \