circuitpython/extmod/modujson.c
2021-05-03 14:01:18 -07:00

379 lines
13 KiB
C

// SPDX-FileCopyrightText: 2014 MicroPython & CircuitPython contributors (https://github.com/adafruit/circuitpython/graphs/contributors)
// SPDX-FileCopyrightText: Copyright (c) 2014-2019 Damien P. George
//
// SPDX-License-Identifier: MIT
#include <stdio.h>
#include "py/binary.h"
#include "py/objarray.h"
#include "py/objlist.h"
#include "py/objstringio.h"
#include "py/parsenum.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "supervisor/shared/translate.h"
#if MICROPY_PY_UJSON
STATIC mp_obj_t mod_ujson_dump(mp_obj_t obj, mp_obj_t stream) {
mp_get_stream_raise(stream, MP_STREAM_OP_WRITE);
mp_print_t print = {MP_OBJ_TO_PTR(stream), mp_stream_write_adaptor};
mp_obj_print_helper(&print, obj, PRINT_JSON);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(mod_ujson_dump_obj, mod_ujson_dump);
STATIC mp_obj_t mod_ujson_dumps(mp_obj_t obj) {
vstr_t vstr;
mp_print_t print;
vstr_init_print(&vstr, 8, &print);
mp_obj_print_helper(&print, obj, PRINT_JSON);
return mp_obj_new_str_from_vstr(&mp_type_str, &vstr);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_ujson_dumps_obj, mod_ujson_dumps);
#define JSON_DEBUG(...) (void)0
// #define JSON_DEBUG(...) mp_printf(&mp_plat_print __VA_OPT__(,) __VA_ARGS__)
// The function below implements a simple non-recursive JSON parser.
//
// The JSON specification is at http://www.ietf.org/rfc/rfc4627.txt
// The parser here will parse any valid JSON and return the correct
// corresponding Python object. It allows through a superset of JSON, since
// it treats commas and colons as "whitespace", and doesn't care if
// brackets/braces are correctly paired. It will raise a ValueError if the
// input is outside it's specs.
//
// Most of the work is parsing the primitives (null, false, true, numbers,
// strings). It does 1 pass over the input stream. It tries to be fast and
// small in code size, while not using more RAM than necessary.
typedef struct _ujson_stream_t {
mp_obj_t stream_obj;
mp_uint_t (*read)(mp_obj_t obj, void *buf, mp_uint_t size, int *errcode);
int errcode;
mp_obj_t python_readinto[2 + 1];
mp_obj_array_t bytearray_obj;
size_t start;
size_t end;
byte cur;
} ujson_stream_t;
#define S_EOF (0) // null is not allowed in json stream so is ok as EOF marker
#define S_END(s) ((s).cur == S_EOF)
#define S_CUR(s) ((s).cur)
#define S_NEXT(s) (ujson_stream_next(&(s)))
STATIC byte ujson_stream_next(ujson_stream_t *s) {
mp_uint_t ret = s->read(s->stream_obj, &s->cur, 1, &s->errcode);
JSON_DEBUG(" usjon_stream_next err:%2d cur: %c \n", s->errcode, s->cur);
if (s->errcode != 0) {
mp_raise_OSError(s->errcode);
}
if (ret == 0) {
s->cur = S_EOF;
}
return s->cur;
}
// We read from an object's `readinto` method in chunks larger than the json
// parser needs to reduce the number of function calls done.
#define CIRCUITPY_JSON_READ_CHUNK_SIZE 64
STATIC mp_uint_t ujson_python_readinto(mp_obj_t obj, void *buf, mp_uint_t size, int *errcode) {
(void)size; // Ignore size because we know it's always 1.
ujson_stream_t *s = obj;
if (s->start == s->end) {
*errcode = 0;
mp_obj_t ret = mp_call_method_n_kw(1, 0, s->python_readinto);
if (ret == mp_const_none) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
s->start = 0;
s->end = mp_obj_get_int(ret);
}
*((uint8_t *)buf) = ((uint8_t *)s->bytearray_obj.items)[s->start];
s->start++;
return 1;
}
STATIC mp_obj_t _mod_ujson_load(mp_obj_t stream_obj, bool return_first_json) {
const mp_stream_p_t *stream_p = mp_proto_get(MP_QSTR_protocol_stream, stream_obj);
ujson_stream_t s;
uint8_t character_buffer[CIRCUITPY_JSON_READ_CHUNK_SIZE];
if (stream_p == NULL) {
s.start = 0;
s.end = 0;
mp_load_method(stream_obj, MP_QSTR_readinto, s.python_readinto);
s.bytearray_obj.base.type = &mp_type_bytearray;
s.bytearray_obj.typecode = BYTEARRAY_TYPECODE;
s.bytearray_obj.len = CIRCUITPY_JSON_READ_CHUNK_SIZE;
s.bytearray_obj.free = 0;
s.bytearray_obj.items = character_buffer;
s.python_readinto[2] = MP_OBJ_FROM_PTR(&s.bytearray_obj);
s.stream_obj = &s;
s.read = ujson_python_readinto;
} else {
stream_p = mp_get_stream_raise(stream_obj, MP_STREAM_OP_READ);
s.stream_obj = stream_obj;
s.read = stream_p->read;
s.errcode = 0;
s.cur = 0;
}
JSON_DEBUG("got JSON stream\n");
vstr_t vstr;
vstr_init(&vstr, 8);
mp_obj_list_t stack; // we use a list as a simple stack for nested JSON
stack.len = 0;
stack.items = NULL;
mp_obj_t stack_top = MP_OBJ_NULL;
mp_obj_type_t *stack_top_type = NULL;
mp_obj_t stack_key = MP_OBJ_NULL;
S_NEXT(s);
for (;;) {
cont:
if (S_END(s)) {
break;
}
mp_obj_t next = MP_OBJ_NULL;
bool enter = false;
byte cur = S_CUR(s);
S_NEXT(s);
switch (cur) {
case ',':
case ':':
case ' ':
case '\t':
case '\n':
case '\r':
goto cont;
case 'n':
if (S_CUR(s) == 'u' && S_NEXT(s) == 'l' && S_NEXT(s) == 'l') {
S_NEXT(s);
next = mp_const_none;
} else {
goto fail;
}
break;
case 'f':
if (S_CUR(s) == 'a' && S_NEXT(s) == 'l' && S_NEXT(s) == 's' && S_NEXT(s) == 'e') {
S_NEXT(s);
next = mp_const_false;
} else {
goto fail;
}
break;
case 't':
if (S_CUR(s) == 'r' && S_NEXT(s) == 'u' && S_NEXT(s) == 'e') {
S_NEXT(s);
next = mp_const_true;
} else {
goto fail;
}
break;
case '"':
vstr_reset(&vstr);
for (; !S_END(s) && S_CUR(s) != '"';) {
byte c = S_CUR(s);
if (c == '\\') {
c = S_NEXT(s);
switch (c) {
case 'b':
c = 0x08;
break;
case 'f':
c = 0x0c;
break;
case 'n':
c = 0x0a;
break;
case 'r':
c = 0x0d;
break;
case 't':
c = 0x09;
break;
case 'u': {
mp_uint_t num = 0;
for (int i = 0; i < 4; i++) {
c = (S_NEXT(s) | 0x20) - '0';
if (c > 9) {
c -= ('a' - ('9' + 1));
}
num = (num << 4) | c;
}
vstr_add_char(&vstr, num);
goto str_cont;
}
}
}
vstr_add_byte(&vstr, c);
str_cont:
S_NEXT(s);
}
if (S_END(s)) {
goto fail;
}
S_NEXT(s);
next = mp_obj_new_str(vstr.buf, vstr.len);
break;
case '-':
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9': {
bool flt = false;
vstr_reset(&vstr);
for (;;) {
vstr_add_byte(&vstr, cur);
cur = S_CUR(s);
if (cur == '.' || cur == 'E' || cur == 'e') {
flt = true;
} else if (cur == '+' || cur == '-' || unichar_isdigit(cur)) {
// pass
} else {
break;
}
S_NEXT(s);
}
if (flt) {
next = mp_parse_num_decimal(vstr.buf, vstr.len, false, false, NULL);
} else {
next = mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
}
break;
}
case '[':
next = mp_obj_new_list(0, NULL);
enter = true;
break;
case '{':
next = mp_obj_new_dict(0);
enter = true;
break;
case '}':
case ']': {
if (stack_top == MP_OBJ_NULL) {
// no object at all
goto fail;
}
if (stack.len == 0) {
// finished; compound object
goto success;
}
stack.len -= 1;
stack_top = stack.items[stack.len];
stack_top_type = mp_obj_get_type(stack_top);
goto cont;
}
default:
goto fail;
}
if (stack_top == MP_OBJ_NULL) {
stack_top = next;
stack_top_type = mp_obj_get_type(stack_top);
if (!enter) {
// finished; single primitive only
goto success;
}
} else {
// append to list or dict
if (stack_top_type == &mp_type_list) {
mp_obj_list_append(stack_top, next);
} else {
if (stack_key == MP_OBJ_NULL) {
stack_key = next;
if (enter) {
goto fail;
}
} else {
mp_obj_dict_store(stack_top, stack_key, next);
stack_key = MP_OBJ_NULL;
}
}
if (enter) {
if (stack.items == NULL) {
mp_obj_list_init(&stack, 1);
stack.items[0] = stack_top;
} else {
mp_obj_list_append(MP_OBJ_FROM_PTR(&stack), stack_top);
}
stack_top = next;
stack_top_type = mp_obj_get_type(stack_top);
}
}
}
success:
// It is legal for a stream to have contents after JSON.
// E.g., A UART is not closed after receiving an object; in load() we will
// return the first complete JSON object, while in loads() we will retain
// strict adherence to the buffer's complete semantic.
if (!return_first_json) {
while (unichar_isspace(S_CUR(s))) {
S_NEXT(s);
}
if (!S_END(s)) {
// unexpected chars
goto fail;
}
}
if (stack_top == MP_OBJ_NULL || stack.len != 0) {
// not exactly 1 object
goto fail;
}
vstr_clear(&vstr);
return stack_top;
fail:
mp_raise_ValueError(translate("syntax error in JSON"));
}
STATIC mp_obj_t mod_ujson_load(mp_obj_t stream_obj) {
return _mod_ujson_load(stream_obj, true);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_ujson_load_obj, mod_ujson_load);
STATIC mp_obj_t mod_ujson_loads(mp_obj_t obj) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(obj, &bufinfo, MP_BUFFER_READ);
vstr_t vstr = {bufinfo.len, bufinfo.len, (char *)bufinfo.buf, true};
mp_obj_stringio_t sio = {{&mp_type_stringio}, &vstr, 0, MP_OBJ_NULL};
return _mod_ujson_load(MP_OBJ_FROM_PTR(&sio), false);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mod_ujson_loads_obj, mod_ujson_loads);
STATIC const mp_rom_map_elem_t mp_module_ujson_globals_table[] = {
#if CIRCUITPY
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_json) },
#else
{ MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_ujson) },
#endif
{ MP_ROM_QSTR(MP_QSTR_dump), MP_ROM_PTR(&mod_ujson_dump_obj) },
{ MP_ROM_QSTR(MP_QSTR_dumps), MP_ROM_PTR(&mod_ujson_dumps_obj) },
{ MP_ROM_QSTR(MP_QSTR_load), MP_ROM_PTR(&mod_ujson_load_obj) },
{ MP_ROM_QSTR(MP_QSTR_loads), MP_ROM_PTR(&mod_ujson_loads_obj) },
};
STATIC MP_DEFINE_CONST_DICT(mp_module_ujson_globals, mp_module_ujson_globals_table);
const mp_obj_module_t mp_module_ujson = {
.base = { &mp_type_module },
.globals = (mp_obj_dict_t *)&mp_module_ujson_globals,
};
#endif // MICROPY_PY_UJSON