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feat(json): JSON for apps through vendored lua-cjson

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lua-cjson decodes straight onto the Lua stack, so a response costs its
text plus the table it becomes rather than a document in between, and it
brings the encode half that a C tokenizer would have left to write here.

It is a module rather than a global: a global namespace is a contract a
firmware implements, and nothing about this needs a provider. Registering
into package.preload also puts it ahead of the SD-card searcher, so an
implementation cannot be shadowed, and an app that never requires it
never pays for the module.

Depth is capped at 32 through the module's own knobs rather than by
patching the vendored source. Decoding recurses on the C stack and
upstream defaults to 1000, which assumes a server rather than a FreeRTOS
task.
This commit is contained in:
Evan Reichard
2026-08-05 16:41:51 -04:00
parent b9f7c9347c
commit 772618ef89
13 changed files with 2560 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
native/src/bindings/lib/cjson.cpp
+49
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@@ -0,0 +1,49 @@
// JSON for apps, provided by lua-cjson under native/src/vendor/cjson. It
// decodes straight onto the Lua stack rather than building a document first, so
// a response costs its text plus the table it becomes and nothing in between.
#include <lua/runtime.h>
extern "C" {
#include "lauxlib.h"
#include "lua.h"
int luaopen_cjson(lua_State* state);
}
namespace esp32lua {
namespace bindings {
namespace {
// lua-cjson defaults to 1000 and decodes by recursing on the C stack, which is
// sized for a server rather than a FreeRTOS task. Setting it through the
// module's own knob keeps the vendored source unpatched.
constexpr lua_Integer MAX_DEPTH = 32;
void setDepth(lua_State* state, const char* name) {
lua_getfield(state, -1, name);
lua_pushinteger(state, MAX_DEPTH);
lua_call(state, 1, 0);
}
int open(lua_State* state) {
luaopen_cjson(state);
setDepth(state, "decode_max_depth");
setDepth(state, "encode_max_depth");
return 1;
}
} // namespace
// package.preload rather than a global: the library provides this itself, so no
// firmware implements it and nothing on the SD card shadows it. An app that
// never requires it never pays for the module.
void registerJson(lua_State* state) {
luaL_getsubtable(state, LUA_REGISTRYINDEX, LUA_PRELOAD_TABLE);
lua_pushcfunction(state, open);
lua_setfield(state, -2, "cjson");
lua_pop(state, 1);
}
} // namespace bindings
} // namespace esp32lua
native/src/runtime/runtime.cpp
+2
View File
@@ -12,6 +12,7 @@ void registerBle(lua_State* state);
void registerButtons(lua_State* state);
void registerFs(lua_State* state);
void registerHttp(lua_State* state);
void registerJson(lua_State* state);
void registerLog(lua_State* state);
void registerScreen(lua_State* state);
void registerSys(lua_State* state);
@@ -67,6 +68,7 @@ bool Runtime::open() {
bindings::registerBle(state_);
bindings::registerFs(state_);
bindings::registerHttp(state_);
bindings::registerJson(state_);
bindings::registerLog(state_);
bindings::registerSys(state_);
bindings::registerTimer(state_);
native/src/vendor/cjson/LICENSE
Vendored
+20
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@@ -0,0 +1,20 @@
Copyright (c) 2010-2012 Mark Pulford <mark@kyne.com.au>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
native/src/vendor/cjson/fpconv.c
Vendored
+211
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@@ -0,0 +1,211 @@
/* fpconv - Floating point conversion routines
*
* Copyright (c) 2011-2012 Mark Pulford <mark@kyne.com.au>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/* JSON uses a '.' decimal separator. strtod() / sprintf() under C libraries
* with locale support will break when the decimal separator is a comma.
*
* fpconv_* will around these issues with a translation buffer if required.
*/
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include "fpconv.h"
/* Workaround for MSVC */
#ifdef _MSC_VER
#define inline __inline
#define snprintf sprintf_s
#endif
/* Lua CJSON assumes the locale is the same for all threads within a
* process and doesn't change after initialisation.
*
* This avoids the need for per thread storage or expensive checks
* for call. */
static char locale_decimal_point = '.';
/* In theory multibyte decimal_points are possible, but
* Lua CJSON only supports UTF-8 and known locales only have
* single byte decimal points ([.,]).
*
* localconv() may not be thread safe (=>crash), and nl_langinfo() is
* not supported on some platforms. Use sprintf() instead - if the
* locale does change, at least Lua CJSON won't crash. */
static void fpconv_update_locale(void)
{
char buf[8];
snprintf(buf, sizeof(buf), "%g", 0.5);
/* Failing this test might imply the platform has a buggy dtoa
* implementation or wide characters */
if (buf[0] != '0' || buf[2] != '5' || buf[3] != 0) {
fprintf(stderr, "Error: wide characters found or printf() bug.");
abort();
}
locale_decimal_point = buf[1];
}
/* Check for a valid number character: [-+0-9a-yA-Y.]
* Eg: -0.6e+5, infinity, 0xF0.F0pF0
*
* Used to find the probable end of a number. It doesn't matter if
* invalid characters are counted - strtod() will find the valid
* number if it exists. The risk is that slightly more memory might
* be allocated before a parse error occurs. */
static inline int valid_number_character(char ch)
{
char lower_ch;
if ('0' <= ch && ch <= '9')
return 1;
if (ch == '-' || ch == '+' || ch == '.')
return 1;
/* Hex digits, exponent (e), base (p), "infinity",.. */
lower_ch = ch | 0x20;
if ('a' <= lower_ch && lower_ch <= 'y')
return 1;
return 0;
}
/* Calculate the size of the buffer required for a strtod locale
* conversion. */
static int strtod_buffer_size(const char *s)
{
const char *p = s;
while (valid_number_character(*p))
p++;
return p - s;
}
/* Similar to strtod(), but must be passed the current locale's decimal point
* character. Guaranteed to be called at the start of any valid number in a string */
double fpconv_strtod(const char *nptr, char **endptr)
{
char localbuf[FPCONV_G_FMT_BUFSIZE];
char *buf, *endbuf, *dp;
int buflen;
double value;
/* System strtod() is fine when decimal point is '.' */
if (locale_decimal_point == '.')
return strtod(nptr, endptr);
buflen = strtod_buffer_size(nptr);
if (!buflen) {
/* No valid characters found, standard strtod() return */
*endptr = (char *)nptr;
return 0;
}
/* Duplicate number into buffer */
if (buflen >= FPCONV_G_FMT_BUFSIZE) {
/* Handle unusually large numbers */
buf = (char *)malloc(buflen + 1);
if (!buf) {
fprintf(stderr, "Out of memory");
abort();
}
} else {
/* This is the common case.. */
buf = localbuf;
}
memcpy(buf, nptr, buflen);
buf[buflen] = 0;
/* Update decimal point character if found */
dp = strchr(buf, '.');
if (dp)
*dp = locale_decimal_point;
value = strtod(buf, &endbuf);
*endptr = (char *)&nptr[endbuf - buf];
if (buflen >= FPCONV_G_FMT_BUFSIZE)
free(buf);
return value;
}
/* "fmt" must point to a buffer of at least 6 characters */
static void set_number_format(char *fmt, int precision)
{
int d1, d2, i;
assert(1 <= precision && precision <= 16);
/* Create printf format (%.14g) from precision */
d1 = precision / 10;
d2 = precision % 10;
fmt[0] = '%';
fmt[1] = '.';
i = 2;
if (d1) {
fmt[i++] = '0' + d1;
}
fmt[i++] = '0' + d2;
fmt[i++] = 'g';
fmt[i] = 0;
}
/* Assumes there is always at least 32 characters available in the target buffer */
int fpconv_g_fmt(char *str, double num, int precision)
{
char buf[FPCONV_G_FMT_BUFSIZE];
char fmt[6];
int len;
char *b;
set_number_format(fmt, precision);
/* Pass through when decimal point character is dot. */
if (locale_decimal_point == '.')
return snprintf(str, FPCONV_G_FMT_BUFSIZE, fmt, num);
/* snprintf() to a buffer then translate for other decimal point characters */
len = snprintf(buf, FPCONV_G_FMT_BUFSIZE, fmt, num);
/* Copy into target location. Translate decimal point if required */
b = buf;
do {
*str++ = (*b == locale_decimal_point ? '.' : *b);
} while(*b++);
return len;
}
void fpconv_init(void)
{
fpconv_update_locale();
}
/* vi:ai et sw=4 ts=4:
*/
native/src/vendor/cjson/fpconv.h
Vendored
+32
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@@ -0,0 +1,32 @@
/* Lua CJSON floating point conversion routines */
/* Buffer required to store the largest string representation of a double.
*
* Longest double printed with %.14g is 21 characters long:
* -1.7976931348623e+308 */
# define FPCONV_G_FMT_BUFSIZE 32
#ifdef USE_INTERNAL_FPCONV
#ifdef MULTIPLE_THREADS
#include "dtoa_config.h"
#include <unistd.h>
static inline void fpconv_init()
{
// Add one to try and avoid core id multiplier alignment
set_max_dtoa_threads((sysconf(_SC_NPROCESSORS_CONF) + 1) * 3);
}
#else
static inline void fpconv_init()
{
/* Do nothing - not required */
}
#endif
#else
extern void fpconv_init(void);
#endif
extern int fpconv_g_fmt(char*, double, int);
extern double fpconv_strtod(const char*, char**);
/* vi:ai et sw=4 ts=4:
*/
native/src/vendor/cjson/lua_cjson.c
Vendored
+1827
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File diff suppressed because it is too large Load Diff
native/src/vendor/cjson/strbuf.c
Vendored
+199
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@@ -0,0 +1,199 @@
/* strbuf - String buffer routines
*
* Copyright (c) 2010-2012 Mark Pulford <mark@kyne.com.au>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <stdint.h>
#include "strbuf.h"
static void die(const char *fmt, ...)
{
va_list arg;
va_start(arg, fmt);
vfprintf(stderr, fmt, arg);
va_end(arg);
fprintf(stderr, "\n");
abort();
}
void strbuf_init(strbuf_t *s, size_t len)
{
size_t size;
if (!len)
size = STRBUF_DEFAULT_SIZE;
else
size = len + 1;
if (size < len)
die("Overflow, len: %zu", len);
s->buf = NULL;
s->size = size;
s->length = 0;
s->dynamic = 0;
s->reallocs = 0;
s->debug = 0;
s->buf = (char *)malloc(size);
if (!s->buf)
die("Out of memory");
strbuf_ensure_null(s);
}
strbuf_t *strbuf_new(size_t len)
{
strbuf_t *s;
s = (strbuf_t*)malloc(sizeof(strbuf_t));
if (!s)
die("Out of memory");
strbuf_init(s, len);
/* Dynamic strbuf allocation / deallocation */
s->dynamic = 1;
return s;
}
static inline void debug_stats(strbuf_t *s)
{
if (s->debug) {
fprintf(stderr, "strbuf(%p) reallocs: %d, length: %zd, size: %zd\n",
(void *) s, s->reallocs, s->length, s->size);
}
}
/* If strbuf_t has not been dynamically allocated, strbuf_free() can
* be called any number of times strbuf_init() */
void strbuf_free(strbuf_t *s)
{
debug_stats(s);
if (s->buf) {
free(s->buf);
s->buf = NULL;
}
if (s->dynamic)
free(s);
}
char *strbuf_free_to_string(strbuf_t *s, size_t *len)
{
char *buf;
debug_stats(s);
strbuf_ensure_null(s);
buf = s->buf;
if (len)
*len = s->length;
if (s->dynamic)
free(s);
return buf;
}
static size_t calculate_new_size(strbuf_t *s, size_t len)
{
size_t reqsize, newsize;
if (len <= 0)
die("BUG: Invalid strbuf length requested");
/* Ensure there is room for optional NULL termination */
reqsize = len + 1;
if (reqsize < len)
die("Overflow, len: %zu", len);
/* If the user has requested to shrink the buffer, do it exactly */
if (s->size > reqsize)
return reqsize;
newsize = s->size;
if (reqsize >= SIZE_MAX / 2) {
newsize = reqsize;
} else {
/* Exponential sizing */
while (newsize < reqsize)
newsize *= 2;
}
if (newsize < reqsize)
die("BUG: strbuf length would overflow, len: %zu", len);
return newsize;
}
/* Ensure strbuf can handle a string length bytes long (ignoring NULL
* optional termination). */
void strbuf_resize(strbuf_t *s, size_t len)
{
size_t newsize;
newsize = calculate_new_size(s, len);
if (s->debug > 1) {
fprintf(stderr, "strbuf(%p) resize: %zd => %zd\n",
(void *) s, s->size, newsize);
}
s->size = newsize;
s->buf = (char *)realloc(s->buf, s->size);
if (!s->buf)
die("Out of memory, len: %zu", len);
s->reallocs++;
}
void strbuf_append_string(strbuf_t *s, const char *str)
{
int i;
size_t space;
space = strbuf_empty_length(s);
for (i = 0; str[i]; i++) {
if (space < 1) {
strbuf_resize(s, s->length + 1);
space = strbuf_empty_length(s);
}
s->buf[s->length] = str[i];
s->length++;
space--;
}
}
/* vi:ai et sw=4 ts=4:
*/
native/src/vendor/cjson/strbuf.h
Vendored
+157
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@@ -0,0 +1,157 @@
/* strbuf - String buffer routines
*
* Copyright (c) 2010-2012 Mark Pulford <mark@kyne.com.au>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdlib.h>
#include <stdarg.h>
/* Workaround for MSVC */
#ifdef _MSC_VER
#define inline __inline
#endif
/* Size: Total bytes allocated to *buf
* Length: String length, excluding optional NULL terminator.
* Dynamic: True if created via strbuf_new()
*/
typedef struct {
char *buf;
size_t size;
size_t length;
int dynamic;
int reallocs;
int debug;
} strbuf_t;
#ifndef STRBUF_DEFAULT_SIZE
#define STRBUF_DEFAULT_SIZE 1023
#endif
/* Initialise */
extern strbuf_t *strbuf_new(size_t len);
extern void strbuf_init(strbuf_t *s, size_t len);
/* Release */
extern void strbuf_free(strbuf_t *s);
extern char *strbuf_free_to_string(strbuf_t *s, size_t *len);
/* Management */
extern void strbuf_resize(strbuf_t *s, size_t len);
static size_t strbuf_empty_length(strbuf_t *s);
static size_t strbuf_length(strbuf_t *s);
static char *strbuf_string(strbuf_t *s, size_t *len);
static void strbuf_ensure_empty_length(strbuf_t *s, size_t len);
static char *strbuf_empty_ptr(strbuf_t *s);
static void strbuf_extend_length(strbuf_t *s, size_t len);
static void strbuf_set_length(strbuf_t *s, int len);
/* Update */
static void strbuf_append_mem(strbuf_t *s, const char *c, size_t len);
extern void strbuf_append_string(strbuf_t *s, const char *str);
static void strbuf_append_char(strbuf_t *s, const char c);
static void strbuf_ensure_null(strbuf_t *s);
/* Reset string for before use */
static inline void strbuf_reset(strbuf_t *s)
{
s->length = 0;
}
static inline int strbuf_allocated(strbuf_t *s)
{
return s->buf != NULL;
}
/* Return bytes remaining in the string buffer
* Ensure there is space for a NULL terminator. */
static inline size_t strbuf_empty_length(strbuf_t *s)
{
return s->size - s->length - 1;
}
static inline void strbuf_ensure_empty_length(strbuf_t *s, size_t len)
{
if (len > strbuf_empty_length(s))
strbuf_resize(s, s->length + len);
}
static inline char *strbuf_empty_ptr(strbuf_t *s)
{
return s->buf + s->length;
}
static inline void strbuf_set_length(strbuf_t *s, int len)
{
s->length = len;
}
static inline void strbuf_extend_length(strbuf_t *s, size_t len)
{
s->length += len;
}
static inline size_t strbuf_length(strbuf_t *s)
{
return s->length;
}
static inline void strbuf_append_char(strbuf_t *s, const char c)
{
strbuf_ensure_empty_length(s, 1);
s->buf[s->length++] = c;
}
static inline void strbuf_append_char_unsafe(strbuf_t *s, const char c)
{
s->buf[s->length++] = c;
}
static inline void strbuf_append_mem(strbuf_t *s, const char *c, size_t len)
{
strbuf_ensure_empty_length(s, len);
memcpy(s->buf + s->length, c, len);
s->length += len;
}
static inline void strbuf_append_mem_unsafe(strbuf_t *s, const char *c, size_t len)
{
memcpy(s->buf + s->length, c, len);
s->length += len;
}
static inline void strbuf_ensure_null(strbuf_t *s)
{
s->buf[s->length] = 0;
}
static inline char *strbuf_string(strbuf_t *s, size_t *len)
{
if (len)
*len = s->length;
return s->buf;
}
/* vi:ai et sw=4 ts=4:
*/