/*
* JSON Writer
*
* Copyright IBM, Corp. 2009
* Copyright (c) 2010-2020 Red Hat Inc.
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
* Markus Armbruster <armbru@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/qmp/json-writer.h"
#include "qemu/unicode.h"
struct JSONWriter {
bool pretty;
bool need_comma;
GString *contents;
GByteArray *container_is_array;
};
JSONWriter *json_writer_new(bool pretty)
{
JSONWriter *writer = g_new(JSONWriter, 1);
writer->pretty = pretty;
writer->need_comma = false;
writer->contents = g_string_new(NULL);
writer->container_is_array = g_byte_array_new();
return writer;
}
const char *json_writer_get(JSONWriter *writer)
{
g_assert(!writer->container_is_array->len);
return writer->contents->str;
}
GString *json_writer_get_and_free(JSONWriter *writer)
{
GString *contents = writer->contents;
writer->contents = NULL;
g_byte_array_free(writer->container_is_array, true);
g_free(writer);
return contents;
}
void json_writer_free(JSONWriter *writer)
{
if (writer) {
g_string_free(json_writer_get_and_free(writer), true);
}
}
static void enter_container(JSONWriter *writer, bool is_array)
{
unsigned depth = writer->container_is_array->len;
g_byte_array_set_size(writer->container_is_array, depth + 1);
writer->container_is_array->data[depth] = is_array;
writer->need_comma = false;
}
static void leave_container(JSONWriter *writer, bool is_array)
{
unsigned depth = writer->container_is_array->len;
assert(depth);
assert(writer->container_is_array->data[depth - 1] == is_array);
g_byte_array_set_size(writer->container_is_array, depth - 1);
writer->need_comma = true;
}
static bool in_object(JSONWriter *writer)
{
unsigned depth = writer->container_is_array->len;
return depth && !writer->container_is_array->data[depth - 1];
}
static void pretty_newline(JSONWriter *writer)
{
if (writer->pretty) {
g_string_append_printf(writer->contents, "\n%*s",
writer->container_is_array->len * 4, "");
}
}
static void pretty_newline_or_space(JSONWriter *writer)
{
if (writer->pretty) {
g_string_append_printf(writer->contents, "\n%*s",
writer->container_is_array->len * 4, "");
} else {
g_string_append_c(writer->contents, ' ');
}
}
static void quoted_str(JSONWriter *writer, const char *str)
{
const char *ptr;
char *end;
int cp;
g_string_append_c(writer->contents, '"');
for (ptr = str; *ptr; ptr = end) {
cp = mod_utf8_codepoint(ptr, 6, &end);
switch (cp) {
case '\"':
g_string_append(writer->contents, "\\\"");
break;
case '\\':
g_string_append(writer->contents, "\\\\");
break;
case '\b':
g_string_append(writer->contents, "\\b");
break;
case '\f':
g_string_append(writer->contents, "\\f");
break;
case '\n':
g_string_append(writer->contents, "\\n");
break;
case '\r':
g_string_append(writer->contents, "\\r");
break;
case '\t':
g_string_append(writer->contents, "\\t");
break;
default:
if (cp < 0) {
cp = 0xFFFD; /* replacement character */
}
if (cp > 0xFFFF) {
/* beyond BMP; need a surrogate pair */
g_string_append_printf(writer->contents, "\\u%04X\\u%04X",
0xD800 + ((cp - 0x10000) >> 10),
0xDC00 + ((cp - 0x10000) & 0x3FF));
} else if (cp < 0x20 || cp >= 0x7F) {
g_string_append_printf(writer->contents, "\\u%04X", cp);
} else {
g_string_append_c(writer->contents, cp);
}
}
};
g_string_append_c(writer->contents, '"');
}
static void maybe_comma_name(JSONWriter *writer, const char *name)
{
if (writer->need_comma) {
g_string_append_c(writer->contents, ',');
pretty_newline_or_space(writer);
} else {
if (writer->contents->len) {
pretty_newline(writer);
}
writer->need_comma = true;
}
if (in_object(writer)) {
quoted_str(writer, name);
g_string_append(writer->contents, ": ");
}
}
void json_writer_start_object(JSONWriter *writer, const char *name)
{
maybe_comma_name(writer, name);
g_string_append_c(writer->contents, '{');
enter_container(writer, false);
}
void json_writer_end_object(JSONWriter *writer)
{
leave_container(writer, false);
pretty_newline(writer);
g_string_append_c(writer->contents, '}');
}
void json_writer_start_array(JSONWriter *writer, const char *name)
{
maybe_comma_name(writer, name);
g_string_append_c(writer->contents, '[');
enter_container(writer, true);
}
void json_writer_end_array(JSONWriter *writer)
{
leave_container(writer, true);
pretty_newline(writer);
g_string_append_c(writer->contents, ']');
}
void json_writer_bool(JSONWriter *writer, const char *name, bool val)
{
maybe_comma_name(writer, name);
g_string_append(writer->contents, val ? "true" : "false");
}
void json_writer_null(JSONWriter *writer, const char *name)
{
maybe_comma_name(writer, name);
g_string_append(writer->contents, "null");
}
void json_writer_int64(JSONWriter *writer, const char *name, int64_t val)
{
maybe_comma_name(writer, name);
g_string_append_printf(writer->contents, "%" PRId64, val);
}
void json_writer_uint64(JSONWriter *writer, const char *name, uint64_t val)
{
maybe_comma_name(writer, name);
g_string_append_printf(writer->contents, "%" PRIu64, val);
}
void json_writer_double(JSONWriter *writer, const char *name, double val)
{
maybe_comma_name(writer, name);
/*
* FIXME: g_string_append_printf() is locale dependent; but JSON
* requires numbers to be formatted as if in the C locale.
* Dependence on C locale is a pervasive issue in QEMU.
*/
/*
* FIXME: This risks printing Inf or NaN, which are not valid
* JSON values.
*/
g_string_append_printf(writer->contents, "%.17g", val);
}
void json_writer_str(JSONWriter *writer, const char *name, const char *str)
{
maybe_comma_name(writer, name);
quoted_str(writer, str);
}
