Markus Armbruster | 998da0b | 2020-12-11 18:11:47 +0100 | [diff] [blame] | 1 | /* |
| 2 | * JSON Writer |
| 3 | * |
| 4 | * Copyright IBM, Corp. 2009 |
| 5 | * Copyright (c) 2010-2020 Red Hat Inc. |
| 6 | * |
| 7 | * Authors: |
| 8 | * Anthony Liguori <aliguori@us.ibm.com> |
| 9 | * Markus Armbruster <armbru@redhat.com> |
| 10 | * |
| 11 | * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. |
| 12 | * See the COPYING.LIB file in the top-level directory. |
| 13 | * |
| 14 | */ |
| 15 | |
| 16 | #include "qemu/osdep.h" |
| 17 | #include "qapi/qmp/json-writer.h" |
| 18 | #include "qemu/unicode.h" |
| 19 | |
| 20 | struct JSONWriter { |
| 21 | bool pretty; |
| 22 | bool need_comma; |
| 23 | GString *contents; |
| 24 | GByteArray *container_is_array; |
| 25 | }; |
| 26 | |
| 27 | JSONWriter *json_writer_new(bool pretty) |
| 28 | { |
| 29 | JSONWriter *writer = g_new(JSONWriter, 1); |
| 30 | |
| 31 | writer->pretty = pretty; |
| 32 | writer->need_comma = false; |
| 33 | writer->contents = g_string_new(NULL); |
| 34 | writer->container_is_array = g_byte_array_new(); |
| 35 | return writer; |
| 36 | } |
| 37 | |
| 38 | const char *json_writer_get(JSONWriter *writer) |
| 39 | { |
| 40 | g_assert(!writer->container_is_array->len); |
| 41 | return writer->contents->str; |
| 42 | } |
| 43 | |
| 44 | GString *json_writer_get_and_free(JSONWriter *writer) |
| 45 | { |
| 46 | GString *contents = writer->contents; |
| 47 | |
| 48 | writer->contents = NULL; |
| 49 | g_byte_array_free(writer->container_is_array, true); |
| 50 | g_free(writer); |
| 51 | return contents; |
| 52 | } |
| 53 | |
| 54 | void json_writer_free(JSONWriter *writer) |
| 55 | { |
| 56 | if (writer) { |
| 57 | g_string_free(json_writer_get_and_free(writer), true); |
| 58 | } |
| 59 | } |
| 60 | |
| 61 | static void enter_container(JSONWriter *writer, bool is_array) |
| 62 | { |
| 63 | unsigned depth = writer->container_is_array->len; |
| 64 | |
| 65 | g_byte_array_set_size(writer->container_is_array, depth + 1); |
| 66 | writer->container_is_array->data[depth] = is_array; |
| 67 | writer->need_comma = false; |
| 68 | } |
| 69 | |
| 70 | static void leave_container(JSONWriter *writer, bool is_array) |
| 71 | { |
| 72 | unsigned depth = writer->container_is_array->len; |
| 73 | |
| 74 | assert(depth); |
| 75 | assert(writer->container_is_array->data[depth - 1] == is_array); |
| 76 | g_byte_array_set_size(writer->container_is_array, depth - 1); |
| 77 | writer->need_comma = true; |
| 78 | } |
| 79 | |
| 80 | static bool in_object(JSONWriter *writer) |
| 81 | { |
| 82 | unsigned depth = writer->container_is_array->len; |
| 83 | |
| 84 | return depth && !writer->container_is_array->data[depth - 1]; |
| 85 | } |
| 86 | |
| 87 | static void pretty_newline(JSONWriter *writer) |
| 88 | { |
| 89 | if (writer->pretty) { |
| 90 | g_string_append_printf(writer->contents, "\n%*s", |
| 91 | writer->container_is_array->len * 4, ""); |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | static void pretty_newline_or_space(JSONWriter *writer) |
| 96 | { |
| 97 | if (writer->pretty) { |
| 98 | g_string_append_printf(writer->contents, "\n%*s", |
| 99 | writer->container_is_array->len * 4, ""); |
| 100 | } else { |
| 101 | g_string_append_c(writer->contents, ' '); |
| 102 | } |
| 103 | } |
| 104 | |
| 105 | static void quoted_str(JSONWriter *writer, const char *str) |
| 106 | { |
| 107 | const char *ptr; |
| 108 | char *end; |
| 109 | int cp; |
| 110 | |
| 111 | g_string_append_c(writer->contents, '"'); |
| 112 | |
| 113 | for (ptr = str; *ptr; ptr = end) { |
| 114 | cp = mod_utf8_codepoint(ptr, 6, &end); |
| 115 | switch (cp) { |
| 116 | case '\"': |
| 117 | g_string_append(writer->contents, "\\\""); |
| 118 | break; |
| 119 | case '\\': |
| 120 | g_string_append(writer->contents, "\\\\"); |
| 121 | break; |
| 122 | case '\b': |
| 123 | g_string_append(writer->contents, "\\b"); |
| 124 | break; |
| 125 | case '\f': |
| 126 | g_string_append(writer->contents, "\\f"); |
| 127 | break; |
| 128 | case '\n': |
| 129 | g_string_append(writer->contents, "\\n"); |
| 130 | break; |
| 131 | case '\r': |
| 132 | g_string_append(writer->contents, "\\r"); |
| 133 | break; |
| 134 | case '\t': |
| 135 | g_string_append(writer->contents, "\\t"); |
| 136 | break; |
| 137 | default: |
| 138 | if (cp < 0) { |
| 139 | cp = 0xFFFD; /* replacement character */ |
| 140 | } |
| 141 | if (cp > 0xFFFF) { |
| 142 | /* beyond BMP; need a surrogate pair */ |
| 143 | g_string_append_printf(writer->contents, "\\u%04X\\u%04X", |
| 144 | 0xD800 + ((cp - 0x10000) >> 10), |
| 145 | 0xDC00 + ((cp - 0x10000) & 0x3FF)); |
| 146 | } else if (cp < 0x20 || cp >= 0x7F) { |
| 147 | g_string_append_printf(writer->contents, "\\u%04X", cp); |
| 148 | } else { |
| 149 | g_string_append_c(writer->contents, cp); |
| 150 | } |
| 151 | } |
| 152 | }; |
| 153 | |
| 154 | g_string_append_c(writer->contents, '"'); |
| 155 | } |
| 156 | |
| 157 | static void maybe_comma_name(JSONWriter *writer, const char *name) |
| 158 | { |
| 159 | if (writer->need_comma) { |
| 160 | g_string_append_c(writer->contents, ','); |
| 161 | pretty_newline_or_space(writer); |
| 162 | } else { |
| 163 | if (writer->contents->len) { |
| 164 | pretty_newline(writer); |
| 165 | } |
| 166 | writer->need_comma = true; |
| 167 | } |
| 168 | |
| 169 | if (in_object(writer)) { |
| 170 | quoted_str(writer, name); |
| 171 | g_string_append(writer->contents, ": "); |
| 172 | } |
| 173 | } |
| 174 | |
| 175 | void json_writer_start_object(JSONWriter *writer, const char *name) |
| 176 | { |
| 177 | maybe_comma_name(writer, name); |
| 178 | g_string_append_c(writer->contents, '{'); |
| 179 | enter_container(writer, false); |
| 180 | } |
| 181 | |
| 182 | void json_writer_end_object(JSONWriter *writer) |
| 183 | { |
| 184 | leave_container(writer, false); |
| 185 | pretty_newline(writer); |
| 186 | g_string_append_c(writer->contents, '}'); |
| 187 | } |
| 188 | |
| 189 | void json_writer_start_array(JSONWriter *writer, const char *name) |
| 190 | { |
| 191 | maybe_comma_name(writer, name); |
| 192 | g_string_append_c(writer->contents, '['); |
| 193 | enter_container(writer, true); |
| 194 | } |
| 195 | |
| 196 | void json_writer_end_array(JSONWriter *writer) |
| 197 | { |
| 198 | leave_container(writer, true); |
| 199 | pretty_newline(writer); |
| 200 | g_string_append_c(writer->contents, ']'); |
| 201 | } |
| 202 | |
| 203 | void json_writer_bool(JSONWriter *writer, const char *name, bool val) |
| 204 | { |
| 205 | maybe_comma_name(writer, name); |
| 206 | g_string_append(writer->contents, val ? "true" : "false"); |
| 207 | } |
| 208 | |
| 209 | void json_writer_null(JSONWriter *writer, const char *name) |
| 210 | { |
| 211 | maybe_comma_name(writer, name); |
| 212 | g_string_append(writer->contents, "null"); |
| 213 | } |
| 214 | |
| 215 | void json_writer_int64(JSONWriter *writer, const char *name, int64_t val) |
| 216 | { |
| 217 | maybe_comma_name(writer, name); |
| 218 | g_string_append_printf(writer->contents, "%" PRId64, val); |
| 219 | } |
| 220 | |
| 221 | void json_writer_uint64(JSONWriter *writer, const char *name, uint64_t val) |
| 222 | { |
| 223 | maybe_comma_name(writer, name); |
| 224 | g_string_append_printf(writer->contents, "%" PRIu64, val); |
| 225 | } |
| 226 | |
| 227 | void json_writer_double(JSONWriter *writer, const char *name, double val) |
| 228 | { |
| 229 | maybe_comma_name(writer, name); |
| 230 | |
| 231 | /* |
| 232 | * FIXME: g_string_append_printf() is locale dependent; but JSON |
| 233 | * requires numbers to be formatted as if in the C locale. |
| 234 | * Dependence on C locale is a pervasive issue in QEMU. |
| 235 | */ |
| 236 | /* |
| 237 | * FIXME: This risks printing Inf or NaN, which are not valid |
| 238 | * JSON values. |
| 239 | */ |
| 240 | g_string_append_printf(writer->contents, "%.17g", val); |
| 241 | } |
| 242 | |
| 243 | void json_writer_str(JSONWriter *writer, const char *name, const char *str) |
| 244 | { |
| 245 | maybe_comma_name(writer, name); |
| 246 | quoted_str(writer, str); |
| 247 | } |