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.

1 files changed, 5 insertions, 4 deletions

diff --git a/py/obj.h b/py/obj.h
index a5423f082..86f560ff5 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -29,6 +29,7 @@
 #include "py/mpconfig.h"
 #include "py/misc.h"
 #include "py/qstr.h"
+#include "py/mpprint.h"
 
 // All Micro Python objects are at least this type
 // It must be of pointer size
@@ -260,7 +261,7 @@ typedef enum {
     PRINT_EXC_SUBCLASS = 0x80, // Internal flag for printing exception subclasses
 } mp_print_kind_t;
 
-typedef void (*mp_print_fun_t)(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o, mp_print_kind_t kind);
+typedef void (*mp_print_fun_t)(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind);
 typedef mp_obj_t (*mp_make_new_fun_t)(mp_obj_t type_in, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
 typedef mp_obj_t (*mp_call_fun_t)(mp_obj_t fun, mp_uint_t n_args, mp_uint_t n_kw, const mp_obj_t *args);
 typedef mp_obj_t (*mp_unary_op_fun_t)(mp_uint_t op, mp_obj_t);
@@ -499,9 +500,9 @@ const char *mp_obj_get_type_str(mp_const_obj_t o_in);
 bool mp_obj_is_subclass_fast(mp_const_obj_t object, mp_const_obj_t classinfo); // arguments should be type objects
 mp_obj_t mp_instance_cast_to_native_base(mp_const_obj_t self_in, mp_const_obj_t native_type);
 
-void mp_obj_print_helper(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t o_in, mp_print_kind_t kind);
+void mp_obj_print_helper(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind);
 void mp_obj_print(mp_obj_t o, mp_print_kind_t kind);
-void mp_obj_print_exception(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t exc);
+void mp_obj_print_exception(const mp_print_t *print, mp_obj_t exc);
 
 bool mp_obj_is_true(mp_obj_t arg);
 bool mp_obj_is_callable(mp_obj_t o_in);
@@ -561,7 +562,7 @@ qstr mp_obj_str_get_qstr(mp_obj_t self_in); // use this if you will anyway conve
 const char *mp_obj_str_get_str(mp_obj_t self_in); // use this only if you need the string to be null terminated
 const char *mp_obj_str_get_data(mp_obj_t self_in, mp_uint_t *len);
 mp_obj_t mp_obj_str_intern(mp_obj_t str);
-void mp_str_print_quoted(void (*print)(void *env, const char *fmt, ...), void *env, const byte *str_data, mp_uint_t str_len, bool is_bytes);
+void mp_str_print_quoted(const mp_print_t *print, const byte *str_data, mp_uint_t str_len, bool is_bytes);
 
 #if MICROPY_PY_BUILTINS_FLOAT
 // float