plugins/lttng-utils/trace-ir-metadata-copy.c

   1 /*
   2  * Babeltrace - Trace IR metadata object copy
   3  *
   4  * Copyright (c) 2015 EfficiOS Inc. and Linux Foundation
   5  * Copyright (c) 2018 Philippe Proulx <pproulx@efficios.com>
   6  * Copyright (c) 2019 Francis Deslauriers <francis.deslauriers@efficios.com>
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  24  * SOFTWARE.
  25  */
  26
  27 #define BT_LOG_TAG "PLUGIN-LTTNG-UTILS-DEBUG-INFO-TRACE-IR-METADATA-COPY"
  28 #include "logging.h"
  29
  30 #include <inttypes.h>
  31 #include <stdint.h>
  32
  33 #include <babeltrace/assert-internal.h>
  34
  35 #include "trace-ir-metadata-copy.h"
  36 #include "trace-ir-metadata-field-class-copy.h"
  37 #include "utils.h"
  38
  39 BT_HIDDEN
  40 int copy_trace_class_content(const bt_trace_class *in_trace_class,
  41                 bt_trace_class *out_trace_class)
  42 {
  43         int ret = 0;
  44         uint64_t i, env_field_count;
  45         const char *in_trace_class_name;
  46         bt_uuid in_uuid;
  47
  48         BT_LOGD("Copying content of trace class: in-tc-addr=%p, out-tc-addr=%p",
  49                         in_trace_class, out_trace_class);
  50
  51         /* Use the same stream class ids as in the origin trace class. */
  52         bt_trace_class_set_assigns_automatic_stream_class_id(out_trace_class,
  53                         BT_FALSE);
  54
  55         in_trace_class_name = bt_trace_class_get_name(in_trace_class);
  56         if (in_trace_class_name) {
  57                 bt_trace_class_set_name(out_trace_class, in_trace_class_name);
  58         }
  59
  60         in_uuid = bt_trace_class_get_uuid(in_trace_class);
  61         if (in_uuid) {
  62                 bt_trace_class_set_uuid(out_trace_class, in_uuid);
  63         }
  64
  65         /*
  66          * Go over all the entries in the environment section of the trace class
  67          * and copy the content to the new trace class.
  68          */
  69         env_field_count = bt_trace_class_get_environment_entry_count(in_trace_class);
  70         for (i = 0; i < env_field_count; i++) {
  71                 const char *value_name;
  72                 const bt_value *value = NULL;
  73                 bt_trace_class_status trace_class_status;
  74
  75                 bt_trace_class_borrow_environment_entry_by_index_const(
  76                         in_trace_class, i, &value_name, &value);
  77
  78                 BT_LOGD("Copying trace class environnement entry: "
  79                         "index=%" PRId64 ", value-addr=%p, value-name=%s",
  80                         i, value, value_name);
  81
  82                 BT_ASSERT(value_name);
  83                 BT_ASSERT(value);
  84
  85                 if (bt_value_is_integer(value)) {
  86                         trace_class_status =
  87                                 bt_trace_class_set_environment_entry_integer(
  88                                                 out_trace_class, value_name,
  89                                                 bt_value_integer_get(value));
  90                 } else if (bt_value_is_string(value)) {
  91                         trace_class_status =
  92                                 bt_trace_class_set_environment_entry_string(
  93                                         out_trace_class, value_name,
  94                                         bt_value_string_get(value));
  95                 } else {
  96                         abort();
  97                 }
  98
  99                 if (trace_class_status != BT_TRACE_CLASS_STATUS_OK) {
 100                         ret = -1;
 101                         goto error;
 102                 }
 103         }
 104
 105         BT_LOGD("Copied content of trace class: in-tc-addr=%p, out-tc-addr=%p",
 106                         in_trace_class, out_trace_class);
 107 error:
 108         return ret;
 109 }
 110
 111 static
 112 int copy_clock_class_content(const bt_clock_class *in_clock_class,
 113                 bt_clock_class *out_clock_class)
 114 {
 115         bt_clock_class_status status;
 116         const char *clock_class_name, *clock_class_description;
 117         int64_t seconds;
 118         uint64_t cycles;
 119         bt_uuid in_uuid;
 120         int ret = 0;
 121
 122         BT_LOGD("Copying content of clock class: in-cc-addr=%p, out-cc-addr=%p",
 123                         in_clock_class, out_clock_class);
 124
 125         clock_class_name = bt_clock_class_get_name(in_clock_class);
 126
 127         if (clock_class_name) {
 128                 status = bt_clock_class_set_name(out_clock_class, clock_class_name);
 129                 if (status != BT_CLOCK_CLASS_STATUS_OK) {
 130                         BT_LOGE("Error setting clock class' name cc-addr=%p, name=%p",
 131                                 out_clock_class, clock_class_name);
 132                         out_clock_class = NULL;
 133                         ret = -1;
 134                         goto error;
 135                 }
 136         }
 137
 138         clock_class_description = bt_clock_class_get_description(in_clock_class);
 139
 140         if (clock_class_description) {
 141                 status = bt_clock_class_set_description(out_clock_class,
 142                                 clock_class_description);
 143                 if (status != BT_CLOCK_CLASS_STATUS_OK) {
 144                         BT_LOGE("Error setting clock class' description cc-addr=%p, "
 145                                 "name=%p", out_clock_class, clock_class_description);
 146                         out_clock_class = NULL;
 147                         ret = -1;
 148                         goto error;
 149                 }
 150         }
 151
 152         in_uuid = bt_clock_class_get_uuid(in_clock_class);
 153         if (in_uuid) {
 154                 bt_clock_class_set_uuid(out_clock_class, in_uuid);
 155         }
 156
 157         bt_clock_class_set_frequency(out_clock_class,
 158                         bt_clock_class_get_frequency(in_clock_class));
 159         bt_clock_class_set_precision(out_clock_class,
 160                         bt_clock_class_get_precision(in_clock_class));
 161         bt_clock_class_get_offset(in_clock_class, &seconds, &cycles);
 162         bt_clock_class_set_offset(out_clock_class, seconds, cycles);
 163         bt_clock_class_set_origin_is_unix_epoch(out_clock_class,
 164                         bt_clock_class_origin_is_unix_epoch(in_clock_class));
 165
 166         BT_LOGD("Copied content of clock class: in-cc-addr=%p, out-cc-addr=%p",
 167                         in_clock_class, out_clock_class);
 168
 169 error:
 170         return ret;
 171 }
 172
 173 static
 174 bt_clock_class *borrow_mapped_clock_class(
 175                 struct trace_ir_metadata_maps *md_maps,
 176                 const bt_clock_class *in_clock_class)
 177 {
 178         BT_ASSERT(md_maps);
 179         BT_ASSERT(in_clock_class);
 180
 181         return g_hash_table_lookup(md_maps->clock_class_map,
 182                         (gpointer) in_clock_class);
 183 }
 184
 185 static
 186 bt_clock_class *create_new_mapped_clock_class(
 187                 bt_self_component *self_comp,
 188                 struct trace_ir_metadata_maps *md_maps,
 189                 const bt_clock_class *in_clock_class)
 190 {
 191         bt_clock_class *out_clock_class;
 192         int ret;
 193
 194         BT_LOGD("Creating new mapped clock class: in-cc-addr=%p",
 195                         in_clock_class);
 196
 197         BT_ASSERT(md_maps);
 198         BT_ASSERT(in_clock_class);
 199
 200         BT_ASSERT(!borrow_mapped_clock_class(md_maps, in_clock_class));
 201
 202         out_clock_class = bt_clock_class_create(self_comp);
 203         if (!out_clock_class) {
 204                 BT_LOGE_STR("Cannot create clock class");
 205                 goto end;
 206         }
 207         /* If not, create a new one and add it to the mapping. */
 208         ret = copy_clock_class_content(in_clock_class, out_clock_class);
 209         if (ret) {
 210                 BT_LOGE_STR("Cannot copy clock class");
 211                 goto end;
 212         }
 213
 214         g_hash_table_insert(md_maps->clock_class_map,
 215                         (gpointer) in_clock_class, out_clock_class);
 216
 217         BT_LOGD("Created new mapped clock class: in-cc-addr=%p, out-cc-addr=%p",
 218                         in_clock_class, out_clock_class);
 219 end:
 220         return out_clock_class;
 221 }
 222
 223 BT_HIDDEN
 224 int copy_stream_class_content(struct trace_ir_maps *ir_maps,
 225                 const bt_stream_class *in_stream_class,
 226                 bt_stream_class *out_stream_class)
 227 {
 228         struct trace_ir_metadata_maps *md_maps;
 229         const bt_clock_class *in_clock_class;
 230         bt_clock_class *out_clock_class;
 231         const bt_field_class *in_packet_context_fc, *in_common_context_fc;
 232         bt_field_class *out_packet_context_fc, *out_common_context_fc;
 233         bt_stream_class_status status;
 234         const char *in_name;
 235         int ret = 0;
 236
 237         BT_LOGD("Copying content of stream class: in-sc-addr=%p, out-sc-addr=%p",
 238                         in_stream_class, out_stream_class);
 239
 240         md_maps = borrow_metadata_maps_from_input_stream_class(ir_maps, in_stream_class);
 241         in_clock_class = bt_stream_class_borrow_default_clock_class_const(
 242                                 in_stream_class);
 243
 244         if (in_clock_class) {
 245                 /* Copy the clock class. */
 246                 out_clock_class =
 247                         borrow_mapped_clock_class(md_maps, in_clock_class);
 248                 if (!out_clock_class) {
 249                         out_clock_class = create_new_mapped_clock_class(
 250                                         ir_maps->self_comp, md_maps,
 251                                         in_clock_class);
 252                 }
 253                 bt_stream_class_set_default_clock_class(out_stream_class,
 254                                 out_clock_class);
 255
 256         }
 257
 258         in_name = bt_stream_class_get_name(in_stream_class);
 259         if (in_name) {
 260                 status = bt_stream_class_set_name(out_stream_class, in_name);
 261                 if (status != BT_STREAM_CLASS_STATUS_OK) {
 262                         BT_LOGE("Error set stream class name: out-sc-addr=%p, "
 263                                 "name=%s", out_stream_class, in_name);
 264                         ret = -1;
 265                         goto error;
 266                 }
 267         }
 268
 269         bt_stream_class_set_assigns_automatic_stream_id(out_stream_class,
 270                         BT_FALSE);
 271         bt_stream_class_set_assigns_automatic_event_class_id(out_stream_class,
 272                         BT_FALSE);
 273
 274         /*
 275          * Add the input packet context field class to the context to
 276          * resolution in the further steps.
 277          */
 278         in_packet_context_fc =
 279                 bt_stream_class_borrow_packet_context_field_class_const(
 280                                 in_stream_class);
 281         md_maps->fc_resolving_ctx->packet_context =
 282                 in_packet_context_fc;
 283
 284         if (in_packet_context_fc) {
 285                 /* Copy packet context. */
 286                 out_packet_context_fc = create_field_class_copy(
 287                                 md_maps, in_packet_context_fc);
 288
 289                 ret = copy_field_class_content(md_maps,
 290                         in_packet_context_fc, out_packet_context_fc);
 291                 if (ret) {
 292                         ret = -1;
 293                         goto error;
 294                 }
 295
 296                 status = bt_stream_class_set_packet_context_field_class(
 297                                 out_stream_class, out_packet_context_fc);
 298                 if (status !=  BT_STREAM_CLASS_STATUS_OK) {
 299                         BT_LOGE("Error setting stream class' packet context "
 300                                 "field class: sc-addr=%p, packet-fc-addr=%p",
 301                                 out_stream_class, out_packet_context_fc);
 302                         ret = -1;
 303                         goto error;
 304                 }
 305         }
 306
 307         /*
 308          * Add the input common context field class to the context to
 309          * resolution in the further steps.
 310          */
 311         in_common_context_fc =
 312                 bt_stream_class_borrow_event_common_context_field_class_const(
 313                                 in_stream_class);
 314         md_maps->fc_resolving_ctx->event_common_context =
 315                 in_common_context_fc;
 316
 317         if (in_common_context_fc) {
 318                 /* Copy common context. */
 319                 /* TODO: I find it a bit awkward to have this special function
 320                  * here to add the debug-info field class. I would like to
 321                  * abstract that.*/
 322                 out_common_context_fc = create_field_class_copy(
 323                                 md_maps, in_common_context_fc);
 324
 325                 ret = copy_event_common_context_field_class_content(
 326                                 md_maps, ir_maps->debug_info_field_class_name,
 327                                 in_common_context_fc, out_common_context_fc);
 328                 if (ret) {
 329                         goto error;
 330                 }
 331
 332                 status = bt_stream_class_set_event_common_context_field_class(
 333                                 out_stream_class, out_common_context_fc);
 334                 if (status !=  BT_STREAM_CLASS_STATUS_OK) {
 335                         BT_LOGE("Error setting stream class' packet context "
 336                                 "field class: sc-addr=%p, packet-fc-addr=%p",
 337                                 out_stream_class, out_common_context_fc);
 338                         ret = -1;
 339                         goto error;
 340                 }
 341         }
 342
 343         /* Set packet snapshot boolean fields. */
 344         BT_LOGD("Copied content of stream class: in-sc-addr=%p, out-sc-addr=%p",
 345                         in_stream_class, out_stream_class);
 346 error:
 347         return ret;
 348 }
 349
 350 BT_HIDDEN
 351 int copy_event_class_content(struct trace_ir_maps *ir_maps,
 352                 const bt_event_class *in_event_class,
 353                 bt_event_class *out_event_class)
 354 {
 355         struct trace_ir_metadata_maps *md_maps;
 356         const char *in_event_class_name, *in_emf_uri;
 357         bt_property_availability prop_avail;
 358         bt_event_class_log_level log_level;
 359         bt_event_class_status status;
 360         bt_field_class *out_specific_context_fc, *out_payload_fc;
 361         const bt_field_class *in_event_specific_context, *in_event_payload;
 362         int ret = 0;
 363
 364         BT_LOGD("Copying content of event class: in-ec-addr=%p, out-ec-addr=%p",
 365                         in_event_class, out_event_class);
 366
 367         /* Copy event class name. */
 368         in_event_class_name = bt_event_class_get_name(in_event_class);
 369         if (in_event_class_name) {
 370                 status = bt_event_class_set_name(out_event_class, in_event_class_name);
 371                 if (status != BT_EVENT_CLASS_STATUS_OK) {
 372                         BT_LOGE("Error setting event class' name: ec-addr=%p, "
 373                                 "name=%s", out_event_class, in_event_class_name);
 374                         ret = -1;
 375                         goto error;
 376                 }
 377         }
 378
 379         /* Copy event class loglevel. */
 380         prop_avail = bt_event_class_get_log_level(in_event_class, &log_level);
 381         if (prop_avail == BT_PROPERTY_AVAILABILITY_AVAILABLE) {
 382                 bt_event_class_set_log_level(out_event_class,
 383                                 log_level);
 384         }
 385
 386         /* Copy event class emf uri. */
 387         in_emf_uri = bt_event_class_get_emf_uri(in_event_class);
 388         if (in_emf_uri) {
 389                 status = bt_event_class_set_emf_uri(out_event_class, in_emf_uri);
 390                 if (status != BT_EVENT_CLASS_STATUS_OK) {
 391                         BT_LOGE("Error setting event class' emf uri: ec-addr=%p, "
 392                                 "emf uri=%s", out_event_class, in_emf_uri);
 393                         ret = -1;
 394                         goto error;
 395                 }
 396         }
 397
 398         md_maps = borrow_metadata_maps_from_input_event_class(ir_maps, in_event_class);
 399         /*
 400          * Add the input event class' specific ctx to te
 401          * context.
 402          */
 403         in_event_specific_context =
 404                 bt_event_class_borrow_specific_context_field_class_const(
 405                                 in_event_class);
 406
 407         md_maps->fc_resolving_ctx->event_specific_context =
 408                 in_event_specific_context;
 409
 410         if (in_event_specific_context) {
 411                 /* Copy the specific context of this event class. */
 412                 out_specific_context_fc = create_field_class_copy(md_maps,
 413                                 in_event_specific_context);
 414
 415                 copy_field_class_content(md_maps,
 416                                 in_event_specific_context, out_specific_context_fc);
 417                 if (ret) {
 418                         goto error;
 419                 }
 420                 /*
 421                  * Add the output specific context to the output event
 422                  * class.
 423                  */
 424                 status = bt_event_class_set_specific_context_field_class(
 425                                 out_event_class, out_specific_context_fc);
 426                 if (status != BT_EVENT_CLASS_STATUS_OK) {
 427                         BT_LOGE("Error setting event class' specific context "
 428                                 "field class: ec-addr=%p, ctx-fc-addr=%p",
 429                                 out_event_class, out_specific_context_fc);
 430                         ret = -1;
 431                         goto error;
 432                 }
 433         }
 434
 435         /*
 436          * Add the input event class' payload field class to
 437          * the context.
 438          */
 439         in_event_payload = bt_event_class_borrow_payload_field_class_const(
 440                                 in_event_class);
 441
 442         md_maps->fc_resolving_ctx->event_payload = in_event_payload;
 443
 444         if (in_event_payload) {
 445         /* Copy the payload of this event class. */
 446                 out_payload_fc = create_field_class_copy(md_maps,
 447                                 in_event_payload);
 448                 copy_field_class_content(md_maps,
 449                                 in_event_payload, out_payload_fc);
 450                 if (ret) {
 451                         goto error;
 452                 }
 453
 454                 /* Add the output payload to the output event class. */
 455                 status = bt_event_class_set_payload_field_class(
 456                                 out_event_class, out_payload_fc);
 457                 if (status != BT_EVENT_CLASS_STATUS_OK) {
 458                         BT_LOGE("Error setting event class' payload "
 459                                 "field class: ec-addr=%p, payload-fc-addr=%p",
 460                                 out_event_class, out_payload_fc);
 461                         ret = -1;
 462                         goto error;
 463                 }
 464         }
 465
 466         BT_LOGD("Copied content of event class: in-ec-addr=%p, out-ec-addr=%p",
 467                         in_event_class, out_event_class);
 468 error:
 469         return ret;
 470 }
 471
 472 BT_HIDDEN
 473 int copy_event_common_context_field_class_content(
 474                 struct trace_ir_metadata_maps *md_maps,
 475                 const char *debug_info_fc_name,
 476                 const bt_field_class *in_field_class,
 477                 bt_field_class *out_field_class)
 478 {
 479         bt_field_class_status status;
 480         bt_field_class *debug_field_class = NULL, *bin_field_class = NULL,
 481                        *func_field_class = NULL, *src_field_class = NULL;
 482         int ret = 0;
 483
 484         BT_LOGD("Copying content of event common context field class: "
 485                 "in-fc-addr=%p, out-fc-addr=%p", in_field_class, out_field_class);
 486
 487         /* Copy the content of the input common context. */
 488         ret = copy_field_class_content(md_maps, in_field_class, out_field_class);
 489         if (ret) {
 490                 goto error;
 491         }
 492
 493         /*
 494          * If this event common context has the necessary fields to compute the
 495          * debug information append the debug-info field class to the event
 496          * common context.
 497          */
 498         if (is_event_common_ctx_dbg_info_compatible(in_field_class, debug_info_fc_name)) {
 499                 /*
 500                  * The struct field and 3 sub-fields are not stored in the
 501                  * field class map because they don't have input equivalent.
 502                  * We need to put our reference each of these field classes
 503                  * once they are added to their respective containing field
 504                  * classes.
 505                  */
 506                 debug_field_class = bt_field_class_structure_create(
 507                                 md_maps->output_trace_class);
 508                 if (!debug_field_class) {
 509                         BT_LOGE_STR("Failed to create debug_info structure.");
 510                         ret = -1;
 511                         goto error;
 512                 }
 513
 514                 bin_field_class = bt_field_class_string_create(
 515                                 md_maps->output_trace_class);
 516                 if (!bin_field_class) {
 517                         BT_LOGE_STR("Failed to create string for field=bin.");
 518                         ret = -1;
 519                         goto error;
 520                 }
 521
 522                 func_field_class = bt_field_class_string_create(
 523                                 md_maps->output_trace_class);
 524                 if (!func_field_class) {
 525                         BT_LOGE_STR("Failed to create string for field=func.");
 526                         ret = -1;
 527                         goto error;
 528                 }
 529
 530                 src_field_class = bt_field_class_string_create(
 531                                 md_maps->output_trace_class);
 532                 if (!src_field_class) {
 533                         BT_LOGE_STR("Failed to create string for field=src.");
 534                         ret = -1;
 535                         goto error;
 536                 }
 537
 538                 status = bt_field_class_structure_append_member(
 539                                 debug_field_class, "bin", bin_field_class);
 540                 if (status != BT_FIELD_CLASS_STATUS_OK) {
 541                         BT_LOGE_STR("Failed to add a field to debug_info "
 542                                         "struct: field=bin.");
 543                         ret = -1;
 544                         goto error;
 545                 }
 546                 BT_FIELD_CLASS_PUT_REF_AND_RESET(bin_field_class);
 547
 548                 status = bt_field_class_structure_append_member(
 549                                 debug_field_class, "func", func_field_class);
 550                 if (status != BT_FIELD_CLASS_STATUS_OK) {
 551                         BT_LOGE_STR("Failed to add a field to debug_info "
 552                                         "struct: field=func.");
 553                         ret = -1;
 554                         goto error;
 555                 }
 556                 BT_FIELD_CLASS_PUT_REF_AND_RESET(func_field_class);
 557
 558                 status = bt_field_class_structure_append_member(
 559                                 debug_field_class, "src", src_field_class);
 560                 if (status != BT_FIELD_CLASS_STATUS_OK) {
 561                         BT_LOGE_STR("Failed to add a field to debug_info "
 562                                         "struct: field=src.");
 563                         ret = -1;
 564                         goto error;
 565                 }
 566                 BT_FIELD_CLASS_PUT_REF_AND_RESET(src_field_class);
 567
 568                 /*Add the filled debug-info field class to the common context. */
 569                 status = bt_field_class_structure_append_member(out_field_class,
 570                                 debug_info_fc_name,
 571                                 debug_field_class);
 572                 if (status != BT_FIELD_CLASS_STATUS_OK) {
 573                         BT_LOGE_STR("Failed to add debug_info field to "
 574                                         "event common context.");
 575                         ret = -1;
 576                         goto error;
 577                 }
 578                 BT_FIELD_CLASS_PUT_REF_AND_RESET(debug_field_class);
 579         }
 580         BT_LOGD("Copied content of event common context field class: "
 581                 "in-fc-addr=%p, out-fc-addr=%p", in_field_class, out_field_class);
 582         goto end;
 583
 584 error:
 585         if (debug_field_class) {
 586                 bt_field_class_put_ref(debug_field_class);
 587         }
 588         if (bin_field_class) {
 589                 bt_field_class_put_ref(bin_field_class);
 590         }
 591         if (func_field_class) {
 592                 bt_field_class_put_ref(func_field_class);
 593         }
 594         if (src_field_class) {
 595                 bt_field_class_put_ref(src_field_class);
 596         }
 597 end:
 598         return ret;
 599 }
 600
 601 BT_HIDDEN
 602 bt_field_class *create_field_class_copy(struct trace_ir_metadata_maps *md_maps,
 603                 const bt_field_class *in_field_class)
 604 {
 605         return create_field_class_copy_internal(md_maps, in_field_class);
 606 }
 607
 608 BT_HIDDEN
 609 int copy_field_class_content(struct trace_ir_metadata_maps *md_maps,
 610                 const bt_field_class *in_field_class,
 611                 bt_field_class *out_field_class)
 612 {
 613         return copy_field_class_content_internal(md_maps, in_field_class,
 614                         out_field_class);
 615 }