pipewire/src/json.c
2018-06-01 11:28:31 +02:00

648 lines
16 KiB
C

/***
This file is part of PulseAudio.
Copyright 2016 Arun Raghavan <mail@arunraghavan.net>
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2.1 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
***/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <math.h>
#include <pulse/xmalloc.h>
#include <pipewire/array.h>
#include <pipewire/properties.h>
#include "internal.h"
#include "json.h"
#include "strbuf.h"
#define MAX_NESTING_DEPTH 20 /* Arbitrary number to make sure we don't have a stack overflow */
typedef struct pa_json_item {
char *key;
pa_json_object *value;
} pa_json_item;
struct pa_json_object {
pa_json_type type;
union {
int int_value;
double double_value;
bool bool_value;
char *string_value;
struct pw_array values; /* objects */
};
};
static void clear_array(struct pw_array *array)
{
pa_json_object *value;
pw_array_for_each(value, array)
pa_json_object_free(value);
pw_array_clear(array);
}
static void clear_item(pa_json_item *item)
{
free(item->key);
pa_json_object_free(item->value);
}
static void clear_object(struct pw_array *array)
{
pa_json_item *item;
pw_array_for_each(item, array)
clear_item(item);
pw_array_clear(array);
}
static const char* parse_value(const char *str, const char *end, pa_json_object **obj, unsigned int depth);
static pa_json_object* json_object_new(void) {
pa_json_object *obj;
obj = pa_xnew0(pa_json_object, 1);
return obj;
}
static bool is_whitespace(char c) {
return c == '\t' || c == '\n' || c == '\r' || c == ' ';
}
static bool is_digit(char c) {
return c >= '0' && c <= '9';
}
static bool is_end(const char c, const char *end) {
if (!end)
return c == '\0';
else {
while (*end) {
if (c == *end)
return true;
end++;
}
}
return false;
}
static const char* consume_string(const char *str, const char *expect) {
while (*expect) {
if (*str != *expect)
return NULL;
str++;
expect++;
}
return str;
}
static const char* parse_null(const char *str, pa_json_object *obj) {
str = consume_string(str, "null");
if (str)
obj->type = PA_JSON_TYPE_NULL;
return str;
}
static const char* parse_boolean(const char *str, pa_json_object *obj) {
const char *tmp;
tmp = consume_string(str, "true");
if (tmp) {
obj->type = PA_JSON_TYPE_BOOL;
obj->bool_value = true;
} else {
tmp = consume_string(str, "false");
if (str) {
obj->type = PA_JSON_TYPE_BOOL;
obj->bool_value = false;
}
}
return tmp;
}
static const char* parse_string(const char *str, pa_json_object *obj) {
pa_strbuf *buf = pa_strbuf_new();
str++; /* Consume leading '"' */
while (*str && *str != '"') {
if (*str != '\\') {
/* We only accept ASCII printable characters. */
if (*str < 0x20 || *str > 0x7E) {
pa_log("Invalid non-ASCII character: 0x%x", (unsigned int) *str);
goto error;
}
/* Normal character, juts consume */
pa_strbuf_putc(buf, *str);
} else {
/* Need to unescape */
str++;
switch (*str) {
case '"':
case '\\':
case '/':
pa_strbuf_putc(buf, *str);
break;
case 'b':
pa_strbuf_putc(buf, '\b' /* backspace */);
break;
case 'f':
pa_strbuf_putc(buf, '\f' /* form feed */);
break;
case 'n':
pa_strbuf_putc(buf, '\n' /* new line */);
break;
case 'r':
pa_strbuf_putc(buf, '\r' /* carriage return */);
break;
case 't':
pa_strbuf_putc(buf, '\t' /* horizontal tab */);
break;
case 'u':
pa_log("Unicode code points are currently unsupported");
goto error;
default:
pa_log("Unexepcted escape value: %c", *str);
goto error;
}
}
str++;
}
if (*str != '"') {
pa_log("Failed to parse remainder of string: %s", str);
goto error;
}
str++;
obj->type = PA_JSON_TYPE_STRING;
obj->string_value = pa_strbuf_to_string_free(buf);
return str;
error:
pa_strbuf_free(buf);
return NULL;
}
static const char* parse_number(const char *str, pa_json_object *obj) {
bool negative = false, has_fraction = false, has_exponent = false, valid = false;
unsigned int integer = 0;
unsigned int fraction = 0;
unsigned int fraction_digits = 0;
int exponent = 0;
if (*str == '-') {
negative = true;
str++;
}
if (*str == '0') {
valid = true;
str++;
goto fraction;
}
while (is_digit(*str)) {
valid = true;
if (integer > ((negative ? INT_MAX : UINT_MAX) / 10)) {
pa_log("Integer overflow while parsing number");
goto error;
}
integer = (integer * 10) + (*str - '0');
str++;
}
fraction:
if (!valid) {
pa_log("Missing digits while parsing number");
goto error;
}
if (*str == '.') {
has_fraction = true;
str++;
valid = false;
while (is_digit(*str)) {
valid = true;
if (fraction > (UINT_MAX / 10)) {
pa_log("Integer overflow while parsing fractional part of number");
goto error;
}
fraction = (fraction * 10) + (*str - '0');
fraction_digits++;
str++;
}
if (!valid) {
pa_log("No digit after '.' while parsing fraction");
goto error;
}
}
if (*str == 'e' || *str == 'E') {
bool exponent_negative = false;
has_exponent = true;
str++;
valid = false;
if (*str == '-') {
exponent_negative = true;
str++;
} else if (*str == '+')
str++;
while (is_digit(*str)) {
valid = true;
if (exponent > (INT_MAX / 10)) {
pa_log("Integer overflow while parsing exponent part of number");
goto error;
}
exponent = (exponent * 10) + (*str - '0');
str++;
}
if (!valid) {
pa_log("No digit in exponent while parsing fraction");
goto error;
}
if (exponent_negative)
exponent *= -1;
}
if (has_fraction || has_exponent) {
obj->type = PA_JSON_TYPE_DOUBLE;
obj->double_value =
(negative ? -1.0 : 1.0) * (integer + (double) fraction / pow(10, fraction_digits)) * pow(10, exponent);
} else {
obj->type = PA_JSON_TYPE_INT;
obj->int_value = (negative ? -1 : 1) * integer;
}
return str;
error:
return NULL;
}
static const char *parse_object(const char *str, pa_json_object *obj, unsigned int depth) {
pa_json_object *name = NULL, *value = NULL;
pa_json_item *item;
obj->values = PW_ARRAY_INIT(64);
while (*str != '}') {
str++; /* Consume leading '{' or ',' */
str = parse_value(str, ":", &name, depth + 1);
if (!str || pa_json_object_get_type(name) != PA_JSON_TYPE_STRING) {
pa_log("Could not parse key for object");
goto error;
}
/* Consume the ':' */
str++;
str = parse_value(str, ",}", &value, depth + 1);
if (!str) {
pa_log("Could not parse value for object");
goto error;
}
item = pw_array_add(&obj->values, sizeof(pa_json_item));
item->key = strdup(pa_json_object_get_string(name));
item->value = value;
pa_json_object_free(name);
name = NULL;
value = NULL;
}
/* Drop trailing '}' */
str++;
/* We now know the value was correctly parsed */
obj->type = PA_JSON_TYPE_OBJECT;
return str;
error:
clear_object(&obj->values);
if (name)
pa_json_object_free(name);
if (value)
pa_json_object_free(value);
return NULL;
}
static const char *parse_array(const char *str, pa_json_object *obj, unsigned int depth) {
pa_json_object *value;
obj->values = PW_ARRAY_INIT(64);
while (*str != ']') {
str++; /* Consume leading '[' or ',' */
/* Need to chew up whitespaces as a special case to deal with the
* possibility of an empty array */
while (is_whitespace(*str))
str++;
if (*str == ']')
break;
str = parse_value(str, ",]", &value, depth + 1);
if (!str) {
pa_log("Could not parse value for array");
goto error;
}
pw_array_add_ptr(&obj->values, value);
}
/* Drop trailing ']' */
str++;
/* We now know the value was correctly parsed */
obj->type = PA_JSON_TYPE_ARRAY;
return str;
error:
clear_array(&obj->values);
return NULL;
}
typedef enum {
JSON_PARSER_STATE_INIT,
JSON_PARSER_STATE_FINISH,
} json_parser_state;
static const char* parse_value(const char *str, const char *end, pa_json_object **obj, unsigned int depth) {
json_parser_state state = JSON_PARSER_STATE_INIT;
pa_json_object *o;
pa_assert(str != NULL);
o = json_object_new();
if (depth > MAX_NESTING_DEPTH) {
pa_log("Exceeded maximum permitted nesting depth of objects (%u)", MAX_NESTING_DEPTH);
goto error;
}
while (!is_end(*str, end)) {
switch (state) {
case JSON_PARSER_STATE_INIT:
if (is_whitespace(*str)) {
str++;
} else if (*str == 'n') {
str = parse_null(str, o);
state = JSON_PARSER_STATE_FINISH;
} else if (*str == 't' || *str == 'f') {
str = parse_boolean(str, o);
state = JSON_PARSER_STATE_FINISH;
} else if (*str == '"') {
str = parse_string(str, o);
state = JSON_PARSER_STATE_FINISH;
} else if (is_digit(*str) || *str == '-') {
str = parse_number(str, o);
state = JSON_PARSER_STATE_FINISH;
} else if (*str == '{') {
str = parse_object(str, o, depth);
state = JSON_PARSER_STATE_FINISH;
} else if (*str == '[') {
str = parse_array(str, o, depth);
state = JSON_PARSER_STATE_FINISH;
} else {
pa_log("Invalid JSON string: %s", str);
goto error;
}
if (!str)
goto error;
break;
case JSON_PARSER_STATE_FINISH:
/* Consume trailing whitespaces */
if (is_whitespace(*str)) {
str++;
} else {
goto error;
}
}
}
if (pa_json_object_get_type(o) == PA_JSON_TYPE_INIT) {
/* We didn't actually get any data */
pa_log("No data while parsing json string: '%s' till '%s'", str, pa_strnull(end));
goto error;
}
*obj = o;
return str;
error:
pa_json_object_free(o);
return NULL;
}
pa_json_object* pa_json_parse(const char *str) {
pa_json_object *obj;
str = parse_value(str, NULL, &obj, 0);
if (!str) {
pa_log("JSON parsing failed");
return NULL;
}
if (*str != '\0') {
pa_log("Unable to parse complete JSON string, remainder is: %s", str);
pa_json_object_free(obj);
return NULL;
}
return obj;
}
pa_json_type pa_json_object_get_type(const pa_json_object *obj) {
return obj->type;
}
void pa_json_object_free(pa_json_object *obj) {
switch (pa_json_object_get_type(obj)) {
case PA_JSON_TYPE_INIT:
case PA_JSON_TYPE_INT:
case PA_JSON_TYPE_DOUBLE:
case PA_JSON_TYPE_BOOL:
case PA_JSON_TYPE_NULL:
break;
case PA_JSON_TYPE_STRING:
pa_xfree(obj->string_value);
break;
case PA_JSON_TYPE_OBJECT:
clear_object(&obj->values);
break;
case PA_JSON_TYPE_ARRAY:
clear_array(&obj->values);
break;
default:
pa_assert_not_reached();
}
pa_xfree(obj);
}
int pa_json_object_get_int(const pa_json_object *o) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_INT);
return o->int_value;
}
double pa_json_object_get_double(const pa_json_object *o) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_DOUBLE);
return o->double_value;
}
bool pa_json_object_get_bool(const pa_json_object *o) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_BOOL);
return o->bool_value;
}
const char* pa_json_object_get_string(const pa_json_object *o) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_STRING);
return o->string_value;
}
const pa_json_object* pa_json_object_get_object_member(const pa_json_object *o, const char *name) {
pa_json_item *item;
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_OBJECT);
pw_array_for_each(item, &o->values) {
if (pa_streq(item->key, name))
return item->value;
}
return NULL;
}
int pa_json_object_get_array_length(const pa_json_object *o) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_ARRAY);
return pw_array_get_len(&o->values, const pa_json_object*);
}
const pa_json_object* pa_json_object_get_array_member(const pa_json_object *o, int index) {
pa_assert(pa_json_object_get_type(o) == PA_JSON_TYPE_ARRAY);
return pw_array_get_unchecked_s(&o->values, index, sizeof(pa_json_object*),
const pa_json_object);
}
bool pa_json_object_equal(const pa_json_object *o1, const pa_json_object *o2) {
int i;
if (pa_json_object_get_type(o1) != pa_json_object_get_type(o2))
return false;
switch (pa_json_object_get_type(o1)) {
case PA_JSON_TYPE_NULL:
return true;
case PA_JSON_TYPE_BOOL:
return o1->bool_value == o2->bool_value;
case PA_JSON_TYPE_INT:
return o1->int_value == o2->int_value;
case PA_JSON_TYPE_DOUBLE:
return PA_DOUBLE_IS_EQUAL(o1->double_value, o2->double_value);
case PA_JSON_TYPE_STRING:
return pa_streq(o1->string_value, o2->string_value);
case PA_JSON_TYPE_ARRAY:
if (pa_json_object_get_array_length(o1) != pa_json_object_get_array_length(o2))
return false;
for (i = 0; i < pa_json_object_get_array_length(o1); i++) {
if (!pa_json_object_equal(pa_json_object_get_array_member(o1, i),
pa_json_object_get_array_member(o2, i)))
return false;
}
return true;
case PA_JSON_TYPE_OBJECT: {
const pa_json_object *value;
const pa_json_item *item;
if (o1->values.size != o2->values.size)
return false;
pw_array_for_each(item, &o1->values) {
value = pa_json_object_get_object_member(o2, item->key);
if (!value || !pa_json_object_equal(item->value, value))
return false;
}
return true;
}
default:
pa_assert_not_reached();
}
}