summaryrefslogtreecommitdiff
path: root/tools/bpf/bpftool/json_writer.c
blob: bff7ee026680481a1f5d33464cf4fad52f3c38cd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
// 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