mirror of https://gitee.com/openkylin/linux.git
360 lines
6.9 KiB
C
360 lines
6.9 KiB
C
// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
|
|
/*
|
|
* Simple streaming JSON writer
|
|
*
|
|
* This takes care of the annoying bits of JSON syntax like the commas
|
|
* after elements
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* Authors: Stephen Hemminger <stephen@networkplumber.org>
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdbool.h>
|
|
#include <stdarg.h>
|
|
#include <assert.h>
|
|
#include <malloc.h>
|
|
#include <inttypes.h>
|
|
#include <stdint.h>
|
|
#include <linux/compiler.h>
|
|
|
|
#include "json_writer.h"
|
|
|
|
struct json_writer {
|
|
FILE *out; /* output file */
|
|
unsigned depth; /* nesting */
|
|
bool pretty; /* optional whitepace */
|
|
char sep; /* either nul or comma */
|
|
};
|
|
|
|
/* indentation for pretty print */
|
|
static void jsonw_indent(json_writer_t *self)
|
|
{
|
|
unsigned i;
|
|
for (i = 0; i < self->depth; ++i)
|
|
fputs(" ", self->out);
|
|
}
|
|
|
|
/* end current line and indent if pretty printing */
|
|
static void jsonw_eol(json_writer_t *self)
|
|
{
|
|
if (!self->pretty)
|
|
return;
|
|
|
|
putc('\n', self->out);
|
|
jsonw_indent(self);
|
|
}
|
|
|
|
/* If current object is not empty print a comma */
|
|
static void jsonw_eor(json_writer_t *self)
|
|
{
|
|
if (self->sep != '\0')
|
|
putc(self->sep, self->out);
|
|
self->sep = ',';
|
|
}
|
|
|
|
|
|
/* Output JSON encoded string */
|
|
/* Handles C escapes, does not do Unicode */
|
|
static void jsonw_puts(json_writer_t *self, const char *str)
|
|
{
|
|
putc('"', self->out);
|
|
for (; *str; ++str)
|
|
switch (*str) {
|
|
case '\t':
|
|
fputs("\\t", self->out);
|
|
break;
|
|
case '\n':
|
|
fputs("\\n", self->out);
|
|
break;
|
|
case '\r':
|
|
fputs("\\r", self->out);
|
|
break;
|
|
case '\f':
|
|
fputs("\\f", self->out);
|
|
break;
|
|
case '\b':
|
|
fputs("\\b", self->out);
|
|
break;
|
|
case '\\':
|
|
fputs("\\n", self->out);
|
|
break;
|
|
case '"':
|
|
fputs("\\\"", self->out);
|
|
break;
|
|
case '\'':
|
|
fputs("\\\'", self->out);
|
|
break;
|
|
default:
|
|
putc(*str, self->out);
|
|
}
|
|
putc('"', self->out);
|
|
}
|
|
|
|
/* Create a new JSON stream */
|
|
json_writer_t *jsonw_new(FILE *f)
|
|
{
|
|
json_writer_t *self = malloc(sizeof(*self));
|
|
if (self) {
|
|
self->out = f;
|
|
self->depth = 0;
|
|
self->pretty = false;
|
|
self->sep = '\0';
|
|
}
|
|
return self;
|
|
}
|
|
|
|
/* End output to JSON stream */
|
|
void jsonw_destroy(json_writer_t **self_p)
|
|
{
|
|
json_writer_t *self = *self_p;
|
|
|
|
assert(self->depth == 0);
|
|
fputs("\n", self->out);
|
|
fflush(self->out);
|
|
free(self);
|
|
*self_p = NULL;
|
|
}
|
|
|
|
void jsonw_pretty(json_writer_t *self, bool on)
|
|
{
|
|
self->pretty = on;
|
|
}
|
|
|
|
/* Basic blocks */
|
|
static void jsonw_begin(json_writer_t *self, int c)
|
|
{
|
|
jsonw_eor(self);
|
|
putc(c, self->out);
|
|
++self->depth;
|
|
self->sep = '\0';
|
|
}
|
|
|
|
static void jsonw_end(json_writer_t *self, int c)
|
|
{
|
|
assert(self->depth > 0);
|
|
|
|
--self->depth;
|
|
if (self->sep != '\0')
|
|
jsonw_eol(self);
|
|
putc(c, self->out);
|
|
self->sep = ',';
|
|
}
|
|
|
|
|
|
/* Add a JSON property name */
|
|
void jsonw_name(json_writer_t *self, const char *name)
|
|
{
|
|
jsonw_eor(self);
|
|
jsonw_eol(self);
|
|
self->sep = '\0';
|
|
jsonw_puts(self, name);
|
|
putc(':', self->out);
|
|
if (self->pretty)
|
|
putc(' ', self->out);
|
|
}
|
|
|
|
void __printf(2, 0)
|
|
jsonw_vprintf_enquote(json_writer_t *self, const char *fmt, va_list ap)
|
|
{
|
|
jsonw_eor(self);
|
|
putc('"', self->out);
|
|
vfprintf(self->out, fmt, ap);
|
|
putc('"', self->out);
|
|
}
|
|
|
|
void __printf(2, 3) jsonw_printf(json_writer_t *self, const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
|
|
va_start(ap, fmt);
|
|
jsonw_eor(self);
|
|
vfprintf(self->out, fmt, ap);
|
|
va_end(ap);
|
|
}
|
|
|
|
/* Collections */
|
|
void jsonw_start_object(json_writer_t *self)
|
|
{
|
|
jsonw_begin(self, '{');
|
|
}
|
|
|
|
void jsonw_end_object(json_writer_t *self)
|
|
{
|
|
jsonw_end(self, '}');
|
|
}
|
|
|
|
void jsonw_start_array(json_writer_t *self)
|
|
{
|
|
jsonw_begin(self, '[');
|
|
}
|
|
|
|
void jsonw_end_array(json_writer_t *self)
|
|
{
|
|
jsonw_end(self, ']');
|
|
}
|
|
|
|
/* JSON value types */
|
|
void jsonw_string(json_writer_t *self, const char *value)
|
|
{
|
|
jsonw_eor(self);
|
|
jsonw_puts(self, value);
|
|
}
|
|
|
|
void jsonw_bool(json_writer_t *self, bool val)
|
|
{
|
|
jsonw_printf(self, "%s", val ? "true" : "false");
|
|
}
|
|
|
|
void jsonw_null(json_writer_t *self)
|
|
{
|
|
jsonw_printf(self, "null");
|
|
}
|
|
|
|
void jsonw_float_fmt(json_writer_t *self, const char *fmt, double num)
|
|
{
|
|
jsonw_printf(self, fmt, num);
|
|
}
|
|
|
|
#ifdef notused
|
|
void jsonw_float(json_writer_t *self, double num)
|
|
{
|
|
jsonw_printf(self, "%g", num);
|
|
}
|
|
#endif
|
|
|
|
void jsonw_hu(json_writer_t *self, unsigned short num)
|
|
{
|
|
jsonw_printf(self, "%hu", num);
|
|
}
|
|
|
|
void jsonw_uint(json_writer_t *self, uint64_t num)
|
|
{
|
|
jsonw_printf(self, "%"PRIu64, num);
|
|
}
|
|
|
|
void jsonw_lluint(json_writer_t *self, unsigned long long int num)
|
|
{
|
|
jsonw_printf(self, "%llu", num);
|
|
}
|
|
|
|
void jsonw_int(json_writer_t *self, int64_t num)
|
|
{
|
|
jsonw_printf(self, "%"PRId64, num);
|
|
}
|
|
|
|
/* Basic name/value objects */
|
|
void jsonw_string_field(json_writer_t *self, const char *prop, const char *val)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_string(self, val);
|
|
}
|
|
|
|
void jsonw_bool_field(json_writer_t *self, const char *prop, bool val)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_bool(self, val);
|
|
}
|
|
|
|
#ifdef notused
|
|
void jsonw_float_field(json_writer_t *self, const char *prop, double val)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_float(self, val);
|
|
}
|
|
#endif
|
|
|
|
void jsonw_float_field_fmt(json_writer_t *self,
|
|
const char *prop,
|
|
const char *fmt,
|
|
double val)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_float_fmt(self, fmt, val);
|
|
}
|
|
|
|
void jsonw_uint_field(json_writer_t *self, const char *prop, uint64_t num)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_uint(self, num);
|
|
}
|
|
|
|
void jsonw_hu_field(json_writer_t *self, const char *prop, unsigned short num)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_hu(self, num);
|
|
}
|
|
|
|
void jsonw_lluint_field(json_writer_t *self,
|
|
const char *prop,
|
|
unsigned long long int num)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_lluint(self, num);
|
|
}
|
|
|
|
void jsonw_int_field(json_writer_t *self, const char *prop, int64_t num)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_int(self, num);
|
|
}
|
|
|
|
void jsonw_null_field(json_writer_t *self, const char *prop)
|
|
{
|
|
jsonw_name(self, prop);
|
|
jsonw_null(self);
|
|
}
|
|
|
|
#ifdef TEST
|
|
int main(int argc, char **argv)
|
|
{
|
|
json_writer_t *wr = jsonw_new(stdout);
|
|
|
|
jsonw_start_object(wr);
|
|
jsonw_pretty(wr, true);
|
|
jsonw_name(wr, "Vyatta");
|
|
jsonw_start_object(wr);
|
|
jsonw_string_field(wr, "url", "http://vyatta.com");
|
|
jsonw_uint_field(wr, "downloads", 2000000ul);
|
|
jsonw_float_field(wr, "stock", 8.16);
|
|
|
|
jsonw_name(wr, "ARGV");
|
|
jsonw_start_array(wr);
|
|
while (--argc)
|
|
jsonw_string(wr, *++argv);
|
|
jsonw_end_array(wr);
|
|
|
|
jsonw_name(wr, "empty");
|
|
jsonw_start_array(wr);
|
|
jsonw_end_array(wr);
|
|
|
|
jsonw_name(wr, "NIL");
|
|
jsonw_start_object(wr);
|
|
jsonw_end_object(wr);
|
|
|
|
jsonw_null_field(wr, "my_null");
|
|
|
|
jsonw_name(wr, "special chars");
|
|
jsonw_start_array(wr);
|
|
jsonw_string_field(wr, "slash", "/");
|
|
jsonw_string_field(wr, "newline", "\n");
|
|
jsonw_string_field(wr, "tab", "\t");
|
|
jsonw_string_field(wr, "ff", "\f");
|
|
jsonw_string_field(wr, "quote", "\"");
|
|
jsonw_string_field(wr, "tick", "\'");
|
|
jsonw_string_field(wr, "backslash", "\\");
|
|
jsonw_end_array(wr);
|
|
|
|
jsonw_end_object(wr);
|
|
|
|
jsonw_end_object(wr);
|
|
jsonw_destroy(&wr);
|
|
return 0;
|
|
}
|
|
|
|
#endif
|