json-writer.c

   1 #include "git-compat-util.h"
   2 #include "json-writer.h"
   3
   4 void jw_init(struct json_writer *jw)
   5 {
   6         struct json_writer blank = JSON_WRITER_INIT;
   7         memcpy(jw, &blank, sizeof(*jw));;
   8 }
   9
  10 void jw_release(struct json_writer *jw)
  11 {
  12         strbuf_release(&jw->json);
  13         strbuf_release(&jw->open_stack);
  14 }
  15
  16 /*
  17  * Append JSON-quoted version of the given string to 'out'.
  18  */
  19 static void append_quoted_string(struct strbuf *out, const char *in)
  20 {
  21         unsigned char c;
  22
  23         strbuf_addch(out, '"');
  24         while ((c = *in++) != '\0') {
  25                 if (c == '"')
  26                         strbuf_addstr(out, "\\\"");
  27                 else if (c == '\\')
  28                         strbuf_addstr(out, "\\\\");
  29                 else if (c == '\n')
  30                         strbuf_addstr(out, "\\n");
  31                 else if (c == '\r')
  32                         strbuf_addstr(out, "\\r");
  33                 else if (c == '\t')
  34                         strbuf_addstr(out, "\\t");
  35                 else if (c == '\f')
  36                         strbuf_addstr(out, "\\f");
  37                 else if (c == '\b')
  38                         strbuf_addstr(out, "\\b");
  39                 else if (c < 0x20)
  40                         strbuf_addf(out, "\\u%04x", c);
  41                 else
  42                         strbuf_addch(out, c);
  43         }
  44         strbuf_addch(out, '"');
  45 }
  46
  47 static void indent_pretty(struct json_writer *jw)
  48 {
  49         strbuf_addstrings(&jw->json, "  ", jw->open_stack.len);
  50 }
  51
  52 /*
  53  * Begin an object or array (either top-level or nested within the currently
  54  * open object or array).
  55  */
  56 static void begin(struct json_writer *jw, char ch_open, int pretty)
  57 {
  58         jw->pretty = pretty;
  59
  60         strbuf_addch(&jw->json, ch_open);
  61
  62         strbuf_addch(&jw->open_stack, ch_open);
  63         jw->need_comma = 0;
  64 }
  65
  66 /*
  67  * Assert that the top of the open-stack is an object.
  68  */
  69 static void assert_in_object(const struct json_writer *jw, const char *key)
  70 {
  71         if (!jw->open_stack.len)
  72                 BUG("json-writer: object: missing jw_object_begin(): '%s'", key);
  73         if (jw->open_stack.buf[jw->open_stack.len - 1] != '{')
  74                 BUG("json-writer: object: not in object: '%s'", key);
  75 }
  76
  77 /*
  78  * Assert that the top of the open-stack is an array.
  79  */
  80 static void assert_in_array(const struct json_writer *jw)
  81 {
  82         if (!jw->open_stack.len)
  83                 BUG("json-writer: array: missing jw_array_begin()");
  84         if (jw->open_stack.buf[jw->open_stack.len - 1] != '[')
  85                 BUG("json-writer: array: not in array");
  86 }
  87
  88 /*
  89  * Add comma if we have already seen a member at this level.
  90  */
  91 static void maybe_add_comma(struct json_writer *jw)
  92 {
  93         if (jw->need_comma)
  94                 strbuf_addch(&jw->json, ',');
  95         else
  96                 jw->need_comma = 1;
  97 }
  98
  99 static void fmt_double(struct json_writer *jw, int precision,
 100                               double value)
 101 {
 102         if (precision < 0) {
 103                 strbuf_addf(&jw->json, "%f", value);
 104         } else {
 105                 struct strbuf fmt = STRBUF_INIT;
 106                 strbuf_addf(&fmt, "%%.%df", precision);
 107                 strbuf_addf(&jw->json, fmt.buf, value);
 108                 strbuf_release(&fmt);
 109         }
 110 }
 111
 112 static void object_common(struct json_writer *jw, const char *key)
 113 {
 114         assert_in_object(jw, key);
 115         maybe_add_comma(jw);
 116
 117         if (jw->pretty) {
 118                 strbuf_addch(&jw->json, '\n');
 119                 indent_pretty(jw);
 120         }
 121
 122         append_quoted_string(&jw->json, key);
 123         strbuf_addch(&jw->json, ':');
 124         if (jw->pretty)
 125                 strbuf_addch(&jw->json, ' ');
 126 }
 127
 128 static void array_common(struct json_writer *jw)
 129 {
 130         assert_in_array(jw);
 131         maybe_add_comma(jw);
 132
 133         if (jw->pretty) {
 134                 strbuf_addch(&jw->json, '\n');
 135                 indent_pretty(jw);
 136         }
 137 }
 138
 139 /*
 140  * Assert that the given JSON object or JSON array has been properly
 141  * terminated.  (Has closing bracket.)
 142  */
 143 static void assert_is_terminated(const struct json_writer *jw)
 144 {
 145         if (jw->open_stack.len)
 146                 BUG("json-writer: object: missing jw_end(): '%s'",
 147                     jw->json.buf);
 148 }
 149
 150 void jw_object_begin(struct json_writer *jw, int pretty)
 151 {
 152         begin(jw, '{', pretty);
 153 }
 154
 155 void jw_object_string(struct json_writer *jw, const char *key, const char *value)
 156 {
 157         object_common(jw, key);
 158         append_quoted_string(&jw->json, value);
 159 }
 160
 161 void jw_object_intmax(struct json_writer *jw, const char *key, intmax_t value)
 162 {
 163         object_common(jw, key);
 164         strbuf_addf(&jw->json, "%"PRIdMAX, value);
 165 }
 166
 167 void jw_object_double(struct json_writer *jw, const char *key, int precision,
 168                       double value)
 169 {
 170         object_common(jw, key);
 171         fmt_double(jw, precision, value);
 172 }
 173
 174 void jw_object_true(struct json_writer *jw, const char *key)
 175 {
 176         object_common(jw, key);
 177         strbuf_addstr(&jw->json, "true");
 178 }
 179
 180 void jw_object_false(struct json_writer *jw, const char *key)
 181 {
 182         object_common(jw, key);
 183         strbuf_addstr(&jw->json, "false");
 184 }
 185
 186 void jw_object_bool(struct json_writer *jw, const char *key, int value)
 187 {
 188         if (value)
 189                 jw_object_true(jw, key);
 190         else
 191                 jw_object_false(jw, key);
 192 }
 193
 194 void jw_object_null(struct json_writer *jw, const char *key)
 195 {
 196         object_common(jw, key);
 197         strbuf_addstr(&jw->json, "null");
 198 }
 199
 200 static void increase_indent(struct strbuf *sb,
 201                             const struct json_writer *jw,
 202                             int indent)
 203 {
 204         int k;
 205
 206         strbuf_reset(sb);
 207         for (k = 0; k < jw->json.len; k++) {
 208                 char ch = jw->json.buf[k];
 209                 strbuf_addch(sb, ch);
 210                 if (ch == '\n')
 211                         strbuf_addchars(sb, ' ', indent);
 212         }
 213 }
 214
 215 static void kill_indent(struct strbuf *sb,
 216                         const struct json_writer *jw)
 217 {
 218         int k;
 219         int eat_it = 0;
 220
 221         strbuf_reset(sb);
 222         for (k = 0; k < jw->json.len; k++) {
 223                 char ch = jw->json.buf[k];
 224                 if (eat_it && ch == ' ')
 225                         continue;
 226                 if (ch == '\n') {
 227                         eat_it = 1;
 228                         continue;
 229                 }
 230                 eat_it = 0;
 231                 strbuf_addch(sb, ch);
 232         }
 233 }
 234
 235 static void append_sub_jw(struct json_writer *jw,
 236                           const struct json_writer *value)
 237 {
 238         /*
 239          * If both are pretty, increase the indentation of the sub_jw
 240          * to better fit under the super.
 241          *
 242          * If the super is pretty, but the sub_jw is compact, leave the
 243          * sub_jw compact.  (We don't want to parse and rebuild the sub_jw
 244          * for this debug-ish feature.)
 245          *
 246          * If the super is compact, and the sub_jw is pretty, convert
 247          * the sub_jw to compact.
 248          *
 249          * If both are compact, keep the sub_jw compact.
 250          */
 251         if (jw->pretty && jw->open_stack.len && value->pretty) {
 252                 struct strbuf sb = STRBUF_INIT;
 253                 increase_indent(&sb, value, jw->open_stack.len * 2);
 254                 strbuf_addbuf(&jw->json, &sb);
 255                 strbuf_release(&sb);
 256                 return;
 257         }
 258         if (!jw->pretty && value->pretty) {
 259                 struct strbuf sb = STRBUF_INIT;
 260                 kill_indent(&sb, value);
 261                 strbuf_addbuf(&jw->json, &sb);
 262                 strbuf_release(&sb);
 263                 return;
 264         }
 265
 266         strbuf_addbuf(&jw->json, &value->json);
 267 }
 268
 269 /*
 270  * Append existing (properly terminated) JSON sub-data (object or array)
 271  * as-is onto the given JSON data.
 272  */
 273 void jw_object_sub_jw(struct json_writer *jw, const char *key,
 274                       const struct json_writer *value)
 275 {
 276         assert_is_terminated(value);
 277
 278         object_common(jw, key);
 279         append_sub_jw(jw, value);
 280 }
 281
 282 void jw_object_inline_begin_object(struct json_writer *jw, const char *key)
 283 {
 284         object_common(jw, key);
 285
 286         jw_object_begin(jw, jw->pretty);
 287 }
 288
 289 void jw_object_inline_begin_array(struct json_writer *jw, const char *key)
 290 {
 291         object_common(jw, key);
 292
 293         jw_array_begin(jw, jw->pretty);
 294 }
 295
 296 void jw_array_begin(struct json_writer *jw, int pretty)
 297 {
 298         begin(jw, '[', pretty);
 299 }
 300
 301 void jw_array_string(struct json_writer *jw, const char *value)
 302 {
 303         array_common(jw);
 304         append_quoted_string(&jw->json, value);
 305 }
 306
 307 void jw_array_intmax(struct json_writer *jw, intmax_t value)
 308 {
 309         array_common(jw);
 310         strbuf_addf(&jw->json, "%"PRIdMAX, value);
 311 }
 312
 313 void jw_array_double(struct json_writer *jw, int precision, double value)
 314 {
 315         array_common(jw);
 316         fmt_double(jw, precision, value);
 317 }
 318
 319 void jw_array_true(struct json_writer *jw)
 320 {
 321         array_common(jw);
 322         strbuf_addstr(&jw->json, "true");
 323 }
 324
 325 void jw_array_false(struct json_writer *jw)
 326 {
 327         array_common(jw);
 328         strbuf_addstr(&jw->json, "false");
 329 }
 330
 331 void jw_array_bool(struct json_writer *jw, int value)
 332 {
 333         if (value)
 334                 jw_array_true(jw);
 335         else
 336                 jw_array_false(jw);
 337 }
 338
 339 void jw_array_null(struct json_writer *jw)
 340 {
 341         array_common(jw);
 342         strbuf_addstr(&jw->json, "null");
 343 }
 344
 345 void jw_array_sub_jw(struct json_writer *jw, const struct json_writer *value)
 346 {
 347         assert_is_terminated(value);
 348
 349         array_common(jw);
 350         append_sub_jw(jw, value);
 351 }
 352
 353 void jw_array_argc_argv(struct json_writer *jw, int argc, const char **argv)
 354 {
 355         int k;
 356
 357         for (k = 0; k < argc; k++)
 358                 jw_array_string(jw, argv[k]);
 359 }
 360
 361 void jw_array_argv(struct json_writer *jw, const char **argv)
 362 {
 363         while (*argv)
 364                 jw_array_string(jw, *argv++);
 365 }
 366
 367 void jw_array_inline_begin_object(struct json_writer *jw)
 368 {
 369         array_common(jw);
 370
 371         jw_object_begin(jw, jw->pretty);
 372 }
 373
 374 void jw_array_inline_begin_array(struct json_writer *jw)
 375 {
 376         array_common(jw);
 377
 378         jw_array_begin(jw, jw->pretty);
 379 }
 380
 381 int jw_is_terminated(const struct json_writer *jw)
 382 {
 383         return !jw->open_stack.len;
 384 }
 385
 386 void jw_end(struct json_writer *jw)
 387 {
 388         char ch_open;
 389         int len;
 390
 391         if (!jw->open_stack.len)
 392                 BUG("json-writer: too many jw_end(): '%s'", jw->json.buf);
 393
 394         len = jw->open_stack.len - 1;
 395         ch_open = jw->open_stack.buf[len];
 396
 397         strbuf_setlen(&jw->open_stack, len);
 398         jw->need_comma = 1;
 399
 400         if (jw->pretty) {
 401                 strbuf_addch(&jw->json, '\n');
 402                 indent_pretty(jw);
 403         }
 404
 405         if (ch_open == '{')
 406                 strbuf_addch(&jw->json, '}');
 407         else
 408                 strbuf_addch(&jw->json, ']');
 409 }