aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/grpc/src/cpp/server/server_cc.cc
blob: c2a911c7f7c4d9965fe14508dd7099e412f52da5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
/*
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <grpcpp/server.h>

#include <cstdlib>
#include <sstream>
#include <type_traits>
#include <utility>

#include <grpc/grpc.h>
#include <grpc/impl/codegen/grpc_types.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpcpp/completion_queue.h>
#include <grpcpp/generic/async_generic_service.h>
#include <grpcpp/impl/codegen/async_unary_call.h>
#include <grpcpp/impl/codegen/byte_buffer.h>
#include <grpcpp/impl/codegen/call.h>
#include <grpcpp/impl/codegen/completion_queue_tag.h>
#include <grpcpp/impl/codegen/method_handler.h>
#include <grpcpp/impl/codegen/server_interceptor.h>
#include <grpcpp/impl/grpc_library.h>
#include <grpcpp/impl/rpc_service_method.h>
#include <grpcpp/impl/server_initializer.h>
#include <grpcpp/impl/service_type.h>
#include <grpcpp/security/server_credentials.h>
#include <grpcpp/server_context.h>
#include <grpcpp/support/time.h>

#include "src/core/ext/transport/inproc/inproc_transport.h"
#include "src/core/lib/iomgr/exec_ctx.h"
#include "src/core/lib/profiling/timers.h"
#include "src/core/lib/surface/call.h"
#include "src/core/lib/surface/completion_queue.h"
#include "src/core/lib/surface/server.h"
#include "src/cpp/client/create_channel_internal.h"
#include "src/cpp/server/external_connection_acceptor_impl.h"
#include "src/cpp/server/health/default_health_check_service.h"
#include "src/cpp/thread_manager/thread_manager.h"

#include <util/stream/str.h>

namespace grpc {
namespace {

// The default value for maximum number of threads that can be created in the
// sync server. This value of INT_MAX is chosen to match the default behavior if
// no ResourceQuota is set. To modify the max number of threads in a sync
// server, pass a custom ResourceQuota object  (with the desired number of
// max-threads set) to the server builder.
#define DEFAULT_MAX_SYNC_SERVER_THREADS INT_MAX

class DefaultGlobalCallbacks final : public Server::GlobalCallbacks {
 public:
  ~DefaultGlobalCallbacks() override {}
  void PreSynchronousRequest(ServerContext* /*context*/) override {}
  void PostSynchronousRequest(ServerContext* /*context*/) override {}
};

std::shared_ptr<Server::GlobalCallbacks> g_callbacks = nullptr;
gpr_once g_once_init_callbacks = GPR_ONCE_INIT;

void InitGlobalCallbacks() {
  if (!g_callbacks) {
    g_callbacks.reset(new DefaultGlobalCallbacks());
  }
}

class ShutdownTag : public internal::CompletionQueueTag {
 public:
  bool FinalizeResult(void** /*tag*/, bool* /*status*/) { return false; }
};

class DummyTag : public internal::CompletionQueueTag {
 public:
  bool FinalizeResult(void** /*tag*/, bool* /*status*/) { return true; }
};

class UnimplementedAsyncRequestContext {
 protected:
  UnimplementedAsyncRequestContext() : generic_stream_(&server_context_) {}

  GenericServerContext server_context_;
  GenericServerAsyncReaderWriter generic_stream_;
};

// TODO(vjpai): Just for this file, use some contents of the experimental
// namespace here to make the code easier to read below. Remove this when
// de-experimentalized fully.
#ifndef GRPC_CALLBACK_API_NONEXPERIMENTAL
using ::grpc::experimental::CallbackGenericService;
using ::grpc::experimental::CallbackServerContext;
using ::grpc::experimental::GenericCallbackServerContext;
#endif

}  // namespace

ServerInterface::BaseAsyncRequest::BaseAsyncRequest(
    ServerInterface* server, ServerContext* context,
    internal::ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
    ServerCompletionQueue* notification_cq, void* tag, bool delete_on_finalize)
    : server_(server),
      context_(context),
      stream_(stream),
      call_cq_(call_cq),
      notification_cq_(notification_cq),
      tag_(tag),
      delete_on_finalize_(delete_on_finalize),
      call_(nullptr),
      done_intercepting_(false) {
  /* Set up interception state partially for the receive ops. call_wrapper_ is
   * not filled at this point, but it will be filled before the interceptors are
   * run. */
  interceptor_methods_.SetCall(&call_wrapper_);
  interceptor_methods_.SetReverse();
  call_cq_->RegisterAvalanching();  // This op will trigger more ops
}

ServerInterface::BaseAsyncRequest::~BaseAsyncRequest() {
  call_cq_->CompleteAvalanching();
}

bool ServerInterface::BaseAsyncRequest::FinalizeResult(void** tag,
                                                       bool* status) {
  if (done_intercepting_) {
    *tag = tag_;
    if (delete_on_finalize_) {
      delete this;
    }
    return true;
  }
  context_->set_call(call_);
  context_->cq_ = call_cq_;
  if (call_wrapper_.call() == nullptr) {
    // Fill it since it is empty.
    call_wrapper_ = internal::Call(
        call_, server_, call_cq_, server_->max_receive_message_size(), nullptr);
  }

  // just the pointers inside call are copied here
  stream_->BindCall(&call_wrapper_);

  if (*status && call_ && call_wrapper_.server_rpc_info()) {
    done_intercepting_ = true;
    // Set interception point for RECV INITIAL METADATA
    interceptor_methods_.AddInterceptionHookPoint(
        experimental::InterceptionHookPoints::POST_RECV_INITIAL_METADATA);
    interceptor_methods_.SetRecvInitialMetadata(&context_->client_metadata_);
    if (interceptor_methods_.RunInterceptors(
            [this]() { ContinueFinalizeResultAfterInterception(); })) {
      // There are no interceptors to run. Continue
    } else {
      // There were interceptors to be run, so
      // ContinueFinalizeResultAfterInterception will be run when interceptors
      // are done.
      return false;
    }
  }
  if (*status && call_) {
    context_->BeginCompletionOp(&call_wrapper_, nullptr, nullptr);
  }
  *tag = tag_;
  if (delete_on_finalize_) {
    delete this;
  }
  return true;
}

void ServerInterface::BaseAsyncRequest::
    ContinueFinalizeResultAfterInterception() {
  context_->BeginCompletionOp(&call_wrapper_, nullptr, nullptr);
  // Queue a tag which will be returned immediately
  grpc_core::ExecCtx exec_ctx;
  grpc_cq_begin_op(notification_cq_->cq(), this);
  grpc_cq_end_op(
      notification_cq_->cq(), this, GRPC_ERROR_NONE,
      [](void* /*arg*/, grpc_cq_completion* completion) { delete completion; },
      nullptr, new grpc_cq_completion());
}

ServerInterface::RegisteredAsyncRequest::RegisteredAsyncRequest(
    ServerInterface* server, ServerContext* context,
    internal::ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
    ServerCompletionQueue* notification_cq, void* tag, const char* name,
    internal::RpcMethod::RpcType type)
    : BaseAsyncRequest(server, context, stream, call_cq, notification_cq, tag,
                       true),
      name_(name),
      type_(type) {}

void ServerInterface::RegisteredAsyncRequest::IssueRequest(
    void* registered_method, grpc_byte_buffer** payload,
    ServerCompletionQueue* notification_cq) {
  // The following call_start_batch is internally-generated so no need for an
  // explanatory log on failure.
  GPR_ASSERT(grpc_server_request_registered_call(
                 server_->server(), registered_method, &call_,
                 &context_->deadline_, context_->client_metadata_.arr(),
                 payload, call_cq_->cq(), notification_cq->cq(),
                 this) == GRPC_CALL_OK);
}

ServerInterface::GenericAsyncRequest::GenericAsyncRequest(
    ServerInterface* server, GenericServerContext* context,
    internal::ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
    ServerCompletionQueue* notification_cq, void* tag, bool delete_on_finalize)
    : BaseAsyncRequest(server, context, stream, call_cq, notification_cq, tag,
                       delete_on_finalize) {
  grpc_call_details_init(&call_details_);
  GPR_ASSERT(notification_cq);
  GPR_ASSERT(call_cq);
  // The following call_start_batch is internally-generated so no need for an
  // explanatory log on failure.
  GPR_ASSERT(grpc_server_request_call(server->server(), &call_, &call_details_,
                                      context->client_metadata_.arr(),
                                      call_cq->cq(), notification_cq->cq(),
                                      this) == GRPC_CALL_OK);
}

bool ServerInterface::GenericAsyncRequest::FinalizeResult(void** tag,
                                                          bool* status) {
  // If we are done intercepting, there is nothing more for us to do
  if (done_intercepting_) {
    return BaseAsyncRequest::FinalizeResult(tag, status);
  }
  // TODO(yangg) remove the copy here.
  if (*status) {
    static_cast<GenericServerContext*>(context_)->method_ =
        StringFromCopiedSlice(call_details_.method);
    static_cast<GenericServerContext*>(context_)->host_ =
        StringFromCopiedSlice(call_details_.host);
    context_->deadline_ = call_details_.deadline;
  }
  grpc_slice_unref(call_details_.method);
  grpc_slice_unref(call_details_.host);
  call_wrapper_ = internal::Call(
      call_, server_, call_cq_, server_->max_receive_message_size(),
      context_->set_server_rpc_info(
          static_cast<GenericServerContext*>(context_)->method_.c_str(),
          internal::RpcMethod::BIDI_STREAMING,
          *server_->interceptor_creators()));
  return BaseAsyncRequest::FinalizeResult(tag, status);
}

namespace {
class ShutdownCallback : public grpc_experimental_completion_queue_functor {
 public:
  ShutdownCallback() {
    functor_run = &ShutdownCallback::Run;
    // Set inlineable to true since this callback is trivial and thus does not
    // need to be run from the executor (triggering a thread hop). This should
    // only be used by internal callbacks like this and not by user application
    // code.
    inlineable = true;
  }
  // TakeCQ takes ownership of the cq into the shutdown callback
  // so that the shutdown callback will be responsible for destroying it
  void TakeCQ(CompletionQueue* cq) { cq_ = cq; }

  // The Run function will get invoked by the completion queue library
  // when the shutdown is actually complete
  static void Run(grpc_experimental_completion_queue_functor* cb, int) {
    auto* callback = static_cast<ShutdownCallback*>(cb);
    delete callback->cq_;
    delete callback;
  }

 private:
  CompletionQueue* cq_ = nullptr;
};
}  // namespace

/// Use private inheritance rather than composition only to establish order
/// of construction, since the public base class should be constructed after the
/// elements belonging to the private base class are constructed. This is not
/// possible using true composition.
class Server::UnimplementedAsyncRequest final
    : private grpc::UnimplementedAsyncRequestContext,
      public GenericAsyncRequest {
 public:
  UnimplementedAsyncRequest(ServerInterface* server,
                            grpc::ServerCompletionQueue* cq)
      : GenericAsyncRequest(server, &server_context_, &generic_stream_, cq, cq,
                            nullptr, false) {}

  bool FinalizeResult(void** tag, bool* status) override;

  grpc::ServerContext* context() { return &server_context_; }
  grpc::GenericServerAsyncReaderWriter* stream() { return &generic_stream_; }
};

/// UnimplementedAsyncResponse should not post user-visible completions to the
/// C++ completion queue, but is generated as a CQ event by the core
class Server::UnimplementedAsyncResponse final
    : public grpc::internal::CallOpSet<
          grpc::internal::CallOpSendInitialMetadata,
          grpc::internal::CallOpServerSendStatus> {
 public:
  UnimplementedAsyncResponse(UnimplementedAsyncRequest* request);
  ~UnimplementedAsyncResponse() { delete request_; }

  bool FinalizeResult(void** tag, bool* status) override {
    if (grpc::internal::CallOpSet<
            grpc::internal::CallOpSendInitialMetadata,
            grpc::internal::CallOpServerSendStatus>::FinalizeResult(tag,
                                                                    status)) {
      delete this;
    } else {
      // The tag was swallowed due to interception. We will see it again.
    }
    return false;
  }

 private:
  UnimplementedAsyncRequest* const request_;
};

class Server::SyncRequest final : public grpc::internal::CompletionQueueTag {
 public:
  SyncRequest(grpc::internal::RpcServiceMethod* method, void* method_tag)
      : method_(method),
        method_tag_(method_tag),
        in_flight_(false),
        has_request_payload_(method->method_type() ==
                                 grpc::internal::RpcMethod::NORMAL_RPC ||
                             method->method_type() ==
                                 grpc::internal::RpcMethod::SERVER_STREAMING),
        call_details_(nullptr),
        cq_(nullptr) {
    grpc_metadata_array_init(&request_metadata_);
  }

  ~SyncRequest() {
    if (call_details_) {
      delete call_details_;
    }
    grpc_metadata_array_destroy(&request_metadata_);
  }

  void SetupRequest() { cq_ = grpc_completion_queue_create_for_pluck(nullptr); }

  void TeardownRequest() {
    grpc_completion_queue_destroy(cq_);
    cq_ = nullptr;
  }

  void Request(grpc_server* server, grpc_completion_queue* notify_cq) {
    GPR_ASSERT(cq_ && !in_flight_);
    in_flight_ = true;
    if (method_tag_) {
      if (grpc_server_request_registered_call(
              server, method_tag_, &call_, &deadline_, &request_metadata_,
              has_request_payload_ ? &request_payload_ : nullptr, cq_,
              notify_cq, this) != GRPC_CALL_OK) {
        TeardownRequest();
        return;
      }
    } else {
      if (!call_details_) {
        call_details_ = new grpc_call_details;
        grpc_call_details_init(call_details_);
      }
      if (grpc_server_request_call(server, &call_, call_details_,
                                   &request_metadata_, cq_, notify_cq,
                                   this) != GRPC_CALL_OK) {
        TeardownRequest();
        return;
      }
    }
  }

  void PostShutdownCleanup() {
    if (call_) {
      grpc_call_unref(call_);
      call_ = nullptr;
    }
    if (cq_) {
      grpc_completion_queue_destroy(cq_);
      cq_ = nullptr;
    }
  }

  bool FinalizeResult(void** /*tag*/, bool* status) override {
    if (!*status) {
      grpc_completion_queue_destroy(cq_);
      cq_ = nullptr;
    }
    if (call_details_) {
      deadline_ = call_details_->deadline;
      grpc_call_details_destroy(call_details_);
      grpc_call_details_init(call_details_);
    }
    return true;
  }

  // The CallData class represents a call that is "active" as opposed
  // to just being requested. It wraps and takes ownership of the cq from
  // the call request
  class CallData final {
   public:
    explicit CallData(Server* server, SyncRequest* mrd)
        : cq_(mrd->cq_),
          ctx_(mrd->deadline_, &mrd->request_metadata_),
          has_request_payload_(mrd->has_request_payload_),
          request_payload_(has_request_payload_ ? mrd->request_payload_
                                                : nullptr),
          request_(nullptr),
          method_(mrd->method_),
          call_(
              mrd->call_, server, &cq_, server->max_receive_message_size(),
              ctx_.set_server_rpc_info(method_->name(), method_->method_type(),
                                       server->interceptor_creators_)),
          server_(server),
          global_callbacks_(nullptr),
          resources_(false) {
      ctx_.set_call(mrd->call_);
      ctx_.cq_ = &cq_;
      GPR_ASSERT(mrd->in_flight_);
      mrd->in_flight_ = false;
      mrd->request_metadata_.count = 0;
    }

    ~CallData() {
      if (has_request_payload_ && request_payload_) {
        grpc_byte_buffer_destroy(request_payload_);
      }
    }

    void Run(const std::shared_ptr<GlobalCallbacks>& global_callbacks,
             bool resources) {
      global_callbacks_ = global_callbacks;
      resources_ = resources;

      interceptor_methods_.SetCall(&call_);
      interceptor_methods_.SetReverse();
      // Set interception point for RECV INITIAL METADATA
      interceptor_methods_.AddInterceptionHookPoint(
          grpc::experimental::InterceptionHookPoints::
              POST_RECV_INITIAL_METADATA);
      interceptor_methods_.SetRecvInitialMetadata(&ctx_.client_metadata_);

      if (has_request_payload_) {
        // Set interception point for RECV MESSAGE
        auto* handler = resources_ ? method_->handler()
                                   : server_->resource_exhausted_handler_.get();
        request_ = handler->Deserialize(call_.call(), request_payload_,
                                        &request_status_, nullptr);

        request_payload_ = nullptr;
        interceptor_methods_.AddInterceptionHookPoint(
            grpc::experimental::InterceptionHookPoints::POST_RECV_MESSAGE);
        interceptor_methods_.SetRecvMessage(request_, nullptr);
      }

      if (interceptor_methods_.RunInterceptors(
              [this]() { ContinueRunAfterInterception(); })) {
        ContinueRunAfterInterception();
      } else {
        // There were interceptors to be run, so ContinueRunAfterInterception
        // will be run when interceptors are done.
      }
    }

    void ContinueRunAfterInterception() {
      {
        ctx_.BeginCompletionOp(&call_, nullptr, nullptr);
        global_callbacks_->PreSynchronousRequest(&ctx_);
        auto* handler = resources_ ? method_->handler()
                                   : server_->resource_exhausted_handler_.get();
        handler->RunHandler(grpc::internal::MethodHandler::HandlerParameter(
            &call_, &ctx_, request_, request_status_, nullptr, nullptr));
        request_ = nullptr;
        global_callbacks_->PostSynchronousRequest(&ctx_);

        cq_.Shutdown();

        grpc::internal::CompletionQueueTag* op_tag = ctx_.GetCompletionOpTag();
        cq_.TryPluck(op_tag, gpr_inf_future(GPR_CLOCK_REALTIME));

        /* Ensure the cq_ is shutdown */
        grpc::DummyTag ignored_tag;
        GPR_ASSERT(cq_.Pluck(&ignored_tag) == false);
      }
      delete this;
    }

   private:
    grpc::CompletionQueue cq_;
    grpc::ServerContext ctx_;
    const bool has_request_payload_;
    grpc_byte_buffer* request_payload_;
    void* request_;
    grpc::Status request_status_;
    grpc::internal::RpcServiceMethod* const method_;
    grpc::internal::Call call_;
    Server* server_;
    std::shared_ptr<GlobalCallbacks> global_callbacks_;
    bool resources_;
    grpc::internal::InterceptorBatchMethodsImpl interceptor_methods_;
  };

 private:
  grpc::internal::RpcServiceMethod* const method_;
  void* const method_tag_;
  bool in_flight_;
  const bool has_request_payload_;
  grpc_call* call_;
  grpc_call_details* call_details_;
  gpr_timespec deadline_;
  grpc_metadata_array request_metadata_;
  grpc_byte_buffer* request_payload_;
  grpc_completion_queue* cq_;
};

template <class ServerContextType>
class Server::CallbackRequest final
    : public grpc::internal::CompletionQueueTag {
 public:
  static_assert(
      std::is_base_of<grpc::CallbackServerContext, ServerContextType>::value,
      "ServerContextType must be derived from CallbackServerContext");

  // For codegen services, the value of method represents the defined
  // characteristics of the method being requested. For generic services, method
  // is nullptr since these services don't have pre-defined methods.
  CallbackRequest(Server* server, grpc::internal::RpcServiceMethod* method,
                  grpc::CompletionQueue* cq,
                  grpc_core::Server::RegisteredCallAllocation* data)
      : server_(server),
        method_(method),
        has_request_payload_(method->method_type() ==
                                 grpc::internal::RpcMethod::NORMAL_RPC ||
                             method->method_type() ==
                                 grpc::internal::RpcMethod::SERVER_STREAMING),
        cq_(cq),
        tag_(this) {
    CommonSetup(server, data);
    data->deadline = &deadline_;
    data->optional_payload = has_request_payload_ ? &request_payload_ : nullptr;
  }

  // For generic services, method is nullptr since these services don't have
  // pre-defined methods.
  CallbackRequest(Server* server, grpc::CompletionQueue* cq,
                  grpc_core::Server::BatchCallAllocation* data)
      : server_(server),
        method_(nullptr),
        has_request_payload_(false),
        call_details_(new grpc_call_details),
        cq_(cq),
        tag_(this) {
    CommonSetup(server, data);
    grpc_call_details_init(call_details_);
    data->details = call_details_;
  }

  ~CallbackRequest() {
    delete call_details_;
    grpc_metadata_array_destroy(&request_metadata_);
    if (has_request_payload_ && request_payload_) {
      grpc_byte_buffer_destroy(request_payload_);
    }
    server_->UnrefWithPossibleNotify();
  }

  // Needs specialization to account for different processing of metadata
  // in generic API
  bool FinalizeResult(void** tag, bool* status) override;

 private:
  // method_name needs to be specialized between named method and generic
  const char* method_name() const;

  class CallbackCallTag : public grpc_experimental_completion_queue_functor {
   public:
    CallbackCallTag(Server::CallbackRequest<ServerContextType>* req)
        : req_(req) {
      functor_run = &CallbackCallTag::StaticRun;
      // Set inlineable to true since this callback is internally-controlled
      // without taking any locks, and thus does not need to be run from the
      // executor (which triggers a thread hop). This should only be used by
      // internal callbacks like this and not by user application code. The work
      // here is actually non-trivial, but there is no chance of having user
      // locks conflict with each other so it's ok to run inlined.
      inlineable = true;
    }

    // force_run can not be performed on a tag if operations using this tag
    // have been sent to PerformOpsOnCall. It is intended for error conditions
    // that are detected before the operations are internally processed.
    void force_run(bool ok) { Run(ok); }

   private:
    Server::CallbackRequest<ServerContextType>* req_;
    grpc::internal::Call* call_;

    static void StaticRun(grpc_experimental_completion_queue_functor* cb,
                          int ok) {
      static_cast<CallbackCallTag*>(cb)->Run(static_cast<bool>(ok));
    }
    void Run(bool ok) {
      void* ignored = req_;
      bool new_ok = ok;
      GPR_ASSERT(!req_->FinalizeResult(&ignored, &new_ok));
      GPR_ASSERT(ignored == req_);

      if (!ok) {
        // The call has been shutdown.
        // Delete its contents to free up the request.
        delete req_;
        return;
      }

      // Bind the call, deadline, and metadata from what we got
      req_->ctx_.set_call(req_->call_);
      req_->ctx_.cq_ = req_->cq_;
      req_->ctx_.BindDeadlineAndMetadata(req_->deadline_,
                                         &req_->request_metadata_);
      req_->request_metadata_.count = 0;

      // Create a C++ Call to control the underlying core call
      call_ =
          new (grpc_call_arena_alloc(req_->call_, sizeof(grpc::internal::Call)))
              grpc::internal::Call(
                  req_->call_, req_->server_, req_->cq_,
                  req_->server_->max_receive_message_size(),
                  req_->ctx_.set_server_rpc_info(
                      req_->method_name(),
                      (req_->method_ != nullptr)
                          ? req_->method_->method_type()
                          : grpc::internal::RpcMethod::BIDI_STREAMING,
                      req_->server_->interceptor_creators_));

      req_->interceptor_methods_.SetCall(call_);
      req_->interceptor_methods_.SetReverse();
      // Set interception point for RECV INITIAL METADATA
      req_->interceptor_methods_.AddInterceptionHookPoint(
          grpc::experimental::InterceptionHookPoints::
              POST_RECV_INITIAL_METADATA);
      req_->interceptor_methods_.SetRecvInitialMetadata(
          &req_->ctx_.client_metadata_);

      if (req_->has_request_payload_) {
        // Set interception point for RECV MESSAGE
        req_->request_ = req_->method_->handler()->Deserialize(
            req_->call_, req_->request_payload_, &req_->request_status_,
            &req_->handler_data_);
        req_->request_payload_ = nullptr;
        req_->interceptor_methods_.AddInterceptionHookPoint(
            grpc::experimental::InterceptionHookPoints::POST_RECV_MESSAGE);
        req_->interceptor_methods_.SetRecvMessage(req_->request_, nullptr);
      }

      if (req_->interceptor_methods_.RunInterceptors(
              [this] { ContinueRunAfterInterception(); })) {
        ContinueRunAfterInterception();
      } else {
        // There were interceptors to be run, so ContinueRunAfterInterception
        // will be run when interceptors are done.
      }
    }
    void ContinueRunAfterInterception() {
      auto* handler = (req_->method_ != nullptr)
                          ? req_->method_->handler()
                          : req_->server_->generic_handler_.get();
      handler->RunHandler(grpc::internal::MethodHandler::HandlerParameter(
          call_, &req_->ctx_, req_->request_, req_->request_status_,
          req_->handler_data_, [this] { delete req_; }));
    }
  };

  template <class CallAllocation>
  void CommonSetup(Server* server, CallAllocation* data) {
    server->Ref();
    grpc_metadata_array_init(&request_metadata_);
    data->tag = &tag_;
    data->call = &call_;
    data->initial_metadata = &request_metadata_;
  }

  Server* const server_;
  grpc::internal::RpcServiceMethod* const method_;
  const bool has_request_payload_;
  grpc_byte_buffer* request_payload_ = nullptr;
  void* request_ = nullptr;
  void* handler_data_ = nullptr;
  grpc::Status request_status_;
  grpc_call_details* const call_details_ = nullptr;
  grpc_call* call_;
  gpr_timespec deadline_;
  grpc_metadata_array request_metadata_;
  grpc::CompletionQueue* const cq_;
  CallbackCallTag tag_;
  ServerContextType ctx_;
  grpc::internal::InterceptorBatchMethodsImpl interceptor_methods_;
};

template <>
bool Server::CallbackRequest<grpc::CallbackServerContext>::FinalizeResult(
    void** /*tag*/, bool* /*status*/) {
  return false;
}

template <>
bool Server::CallbackRequest<
    grpc::GenericCallbackServerContext>::FinalizeResult(void** /*tag*/,
                                                        bool* status) {
  if (*status) {
    deadline_ = call_details_->deadline;
    // TODO(yangg) remove the copy here
    ctx_.method_ = grpc::StringFromCopiedSlice(call_details_->method);
    ctx_.host_ = grpc::StringFromCopiedSlice(call_details_->host);
  }
  grpc_slice_unref(call_details_->method);
  grpc_slice_unref(call_details_->host);
  return false;
}

template <>
const char* Server::CallbackRequest<grpc::CallbackServerContext>::method_name()
    const {
  return method_->name();
}

template <>
const char* Server::CallbackRequest<
    grpc::GenericCallbackServerContext>::method_name() const {
  return ctx_.method().c_str();
}

// Implementation of ThreadManager. Each instance of SyncRequestThreadManager
// manages a pool of threads that poll for incoming Sync RPCs and call the
// appropriate RPC handlers
class Server::SyncRequestThreadManager : public grpc::ThreadManager {
 public:
  SyncRequestThreadManager(Server* server, grpc::CompletionQueue* server_cq,
                           std::shared_ptr<GlobalCallbacks> global_callbacks,
                           grpc_resource_quota* rq, int min_pollers,
                           int max_pollers, int cq_timeout_msec)
      : ThreadManager("SyncServer", rq, min_pollers, max_pollers),
        server_(server),
        server_cq_(server_cq),
        cq_timeout_msec_(cq_timeout_msec),
        global_callbacks_(std::move(global_callbacks)) {}

  WorkStatus PollForWork(void** tag, bool* ok) override {
    *tag = nullptr;
    // TODO(ctiller): workaround for GPR_TIMESPAN based deadlines not working
    // right now
    gpr_timespec deadline =
        gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC),
                     gpr_time_from_millis(cq_timeout_msec_, GPR_TIMESPAN));

    switch (server_cq_->AsyncNext(tag, ok, deadline)) {
      case grpc::CompletionQueue::TIMEOUT:
        return TIMEOUT;
      case grpc::CompletionQueue::SHUTDOWN:
        return SHUTDOWN;
      case grpc::CompletionQueue::GOT_EVENT:
        return WORK_FOUND;
    }

    GPR_UNREACHABLE_CODE(return TIMEOUT);
  }

  void DoWork(void* tag, bool ok, bool resources) override {
    SyncRequest* sync_req = static_cast<SyncRequest*>(tag);

    if (!sync_req) {
      // No tag. Nothing to work on. This is an unlikley scenario and possibly a
      // bug in RPC Manager implementation.
      gpr_log(GPR_ERROR, "Sync server. DoWork() was called with NULL tag");
      return;
    }

    if (ok) {
      // Calldata takes ownership of the completion queue and interceptors
      // inside sync_req
      auto* cd = new SyncRequest::CallData(server_, sync_req);
      // Prepare for the next request
      if (!IsShutdown()) {
        sync_req->SetupRequest();  // Create new completion queue for sync_req
        sync_req->Request(server_->c_server(), server_cq_->cq());
      }

      GPR_TIMER_SCOPE("cd.Run()", 0);
      cd->Run(global_callbacks_, resources);
    }
    // TODO (sreek) If ok is false here (which it isn't in case of
    // grpc_request_registered_call), we should still re-queue the request
    // object
  }

  void AddSyncMethod(grpc::internal::RpcServiceMethod* method, void* tag) {
    sync_requests_.emplace_back(new SyncRequest(method, tag));
  }

  void AddUnknownSyncMethod() {
    if (!sync_requests_.empty()) {
      unknown_method_.reset(new grpc::internal::RpcServiceMethod(
          "unknown", grpc::internal::RpcMethod::BIDI_STREAMING,
          new grpc::internal::UnknownMethodHandler));
      sync_requests_.emplace_back(
          new SyncRequest(unknown_method_.get(), nullptr));
    }
  }

  void Shutdown() override {
    ThreadManager::Shutdown();
    server_cq_->Shutdown();
  }

  void Wait() override {
    ThreadManager::Wait();
    // Drain any pending items from the queue
    void* tag;
    bool ok;
    while (server_cq_->Next(&tag, &ok)) {
      if (ok) {
        // If a request was pulled off the queue, it means that the thread
        // handling the request added it to the completion queue after shutdown
        // was called - because the thread had already started and checked the
        // shutdown flag before shutdown was called. In this case, we simply
        // clean it up here, *after* calling wait on all the worker threads, at
        // which point we are certain no in-flight requests will add more to the
        // queue. This fixes an intermittent memory leak on shutdown.
        SyncRequest* sync_req = static_cast<SyncRequest*>(tag);
        sync_req->PostShutdownCleanup();
      }
    }
  }

  void Start() {
    if (!sync_requests_.empty()) {
      for (const auto& value : sync_requests_) {
        value->SetupRequest();
        value->Request(server_->c_server(), server_cq_->cq());
      }

      Initialize();  // ThreadManager's Initialize()
    }
  }

 private:
  Server* server_;
  grpc::CompletionQueue* server_cq_;
  int cq_timeout_msec_;
  std::vector<std::unique_ptr<SyncRequest>> sync_requests_;
  std::unique_ptr<grpc::internal::RpcServiceMethod> unknown_method_;
  std::shared_ptr<Server::GlobalCallbacks> global_callbacks_;
};

static grpc::internal::GrpcLibraryInitializer g_gli_initializer;
Server::Server(
    grpc::ChannelArguments* args,
    std::shared_ptr<std::vector<std::unique_ptr<grpc::ServerCompletionQueue>>>
        sync_server_cqs,
    int min_pollers, int max_pollers, int sync_cq_timeout_msec,
    std::vector<std::shared_ptr<grpc::internal::ExternalConnectionAcceptorImpl>>
        acceptors,
    grpc_resource_quota* server_rq,
    std::vector<
        std::unique_ptr<grpc::experimental::ServerInterceptorFactoryInterface>>
        interceptor_creators)
    : acceptors_(std::move(acceptors)),
      interceptor_creators_(std::move(interceptor_creators)),
      max_receive_message_size_(INT_MIN),
      sync_server_cqs_(std::move(sync_server_cqs)),
      started_(false),
      shutdown_(false),
      shutdown_notified_(false),
      server_(nullptr),
      server_initializer_(new ServerInitializer(this)),
      health_check_service_disabled_(false) {
  g_gli_initializer.summon();
  gpr_once_init(&grpc::g_once_init_callbacks, grpc::InitGlobalCallbacks);
  global_callbacks_ = grpc::g_callbacks;
  global_callbacks_->UpdateArguments(args);

  if (sync_server_cqs_ != nullptr) {
    bool default_rq_created = false;
    if (server_rq == nullptr) {
      server_rq = grpc_resource_quota_create("SyncServer-default-rq");
      grpc_resource_quota_set_max_threads(server_rq,
                                          DEFAULT_MAX_SYNC_SERVER_THREADS);
      default_rq_created = true;
    }

    for (const auto& it : *sync_server_cqs_) {
      sync_req_mgrs_.emplace_back(new SyncRequestThreadManager(
          this, it.get(), global_callbacks_, server_rq, min_pollers,
          max_pollers, sync_cq_timeout_msec));
    }

    if (default_rq_created) {
      grpc_resource_quota_unref(server_rq);
    }
  }

  for (auto& acceptor : acceptors_) {
    acceptor->SetToChannelArgs(args);
  }

  grpc_channel_args channel_args;
  args->SetChannelArgs(&channel_args);

  for (size_t i = 0; i < channel_args.num_args; i++) {
    if (0 == strcmp(channel_args.args[i].key,
                    grpc::kHealthCheckServiceInterfaceArg)) {
      if (channel_args.args[i].value.pointer.p == nullptr) {
        health_check_service_disabled_ = true;
      } else {
        health_check_service_.reset(
            static_cast<grpc::HealthCheckServiceInterface*>(
                channel_args.args[i].value.pointer.p));
      }
    }
    if (0 ==
        strcmp(channel_args.args[i].key, GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH)) {
      max_receive_message_size_ = channel_args.args[i].value.integer;
    }
  }
  server_ = grpc_server_create(&channel_args, nullptr);
}

Server::~Server() {
  {
    grpc::internal::ReleasableMutexLock lock(&mu_);
    if (started_ && !shutdown_) {
      lock.Unlock();
      Shutdown();
    } else if (!started_) {
      // Shutdown the completion queues
      for (const auto& value : sync_req_mgrs_) {
        value->Shutdown();
      }
      if (callback_cq_ != nullptr) {
        callback_cq_->Shutdown();
        callback_cq_ = nullptr;
      }
    }
  }
  // Destroy health check service before we destroy the C server so that
  // it does not call grpc_server_request_registered_call() after the C
  // server has been destroyed.
  health_check_service_.reset();
  grpc_server_destroy(server_);
}

void Server::SetGlobalCallbacks(GlobalCallbacks* callbacks) {
  GPR_ASSERT(!grpc::g_callbacks);
  GPR_ASSERT(callbacks);
  grpc::g_callbacks.reset(callbacks);
}

grpc_server* Server::c_server() { return server_; }

std::shared_ptr<grpc::Channel> Server::InProcessChannel(
    const grpc::ChannelArguments& args) {
  grpc_channel_args channel_args = args.c_channel_args();
  return grpc::CreateChannelInternal(
      "inproc", grpc_inproc_channel_create(server_, &channel_args, nullptr),
      std::vector<std::unique_ptr<
          grpc::experimental::ClientInterceptorFactoryInterface>>());
}

std::shared_ptr<grpc::Channel>
Server::experimental_type::InProcessChannelWithInterceptors(
    const grpc::ChannelArguments& args,
    std::vector<
        std::unique_ptr<grpc::experimental::ClientInterceptorFactoryInterface>>
        interceptor_creators) {
  grpc_channel_args channel_args = args.c_channel_args();
  return grpc::CreateChannelInternal(
      "inproc",
      grpc_inproc_channel_create(server_->server_, &channel_args, nullptr),
      std::move(interceptor_creators));
}

static grpc_server_register_method_payload_handling PayloadHandlingForMethod(
    grpc::internal::RpcServiceMethod* method) {
  switch (method->method_type()) {
    case grpc::internal::RpcMethod::NORMAL_RPC:
    case grpc::internal::RpcMethod::SERVER_STREAMING:
      return GRPC_SRM_PAYLOAD_READ_INITIAL_BYTE_BUFFER;
    case grpc::internal::RpcMethod::CLIENT_STREAMING:
    case grpc::internal::RpcMethod::BIDI_STREAMING:
      return GRPC_SRM_PAYLOAD_NONE;
  }
  GPR_UNREACHABLE_CODE(return GRPC_SRM_PAYLOAD_NONE;);
}

bool Server::RegisterService(const TString* host, grpc::Service* service) {
  bool has_async_methods = service->has_async_methods();
  if (has_async_methods) {
    GPR_ASSERT(service->server_ == nullptr &&
               "Can only register an asynchronous service against one server.");
    service->server_ = this;
  }

  const char* method_name = nullptr;

  for (const auto& method : service->methods_) {
    if (method.get() == nullptr) {  // Handled by generic service if any.
      continue;
    }

    void* method_registration_tag = grpc_server_register_method(
        server_, method->name(), host ? host->c_str() : nullptr,
        PayloadHandlingForMethod(method.get()), 0);
    if (method_registration_tag == nullptr) {
      gpr_log(GPR_DEBUG, "Attempt to register %s multiple times",
              method->name());
      return false;
    }

    if (method->handler() == nullptr) {  // Async method without handler
      method->set_server_tag(method_registration_tag);
    } else if (method->api_type() ==
               grpc::internal::RpcServiceMethod::ApiType::SYNC) {
      for (const auto& value : sync_req_mgrs_) {
        value->AddSyncMethod(method.get(), method_registration_tag);
      }
    } else {
      has_callback_methods_ = true;
      grpc::internal::RpcServiceMethod* method_value = method.get();
      grpc::CompletionQueue* cq = CallbackCQ();
      server_->core_server->SetRegisteredMethodAllocator(
          cq->cq(), method_registration_tag, [this, cq, method_value] {
            grpc_core::Server::RegisteredCallAllocation result;
            new CallbackRequest<grpc::CallbackServerContext>(this, method_value,
                                                             cq, &result);
            return result;
          });
    }

    method_name = method->name();
  }

  // Parse service name.
  if (method_name != nullptr) {
    std::stringstream ss(method_name);
    std::string service_name;
    if (std::getline(ss, service_name, '/') &&
        std::getline(ss, service_name, '/')) {
      services_.push_back(service_name.c_str());
    }
  }
  return true;
}

void Server::RegisterAsyncGenericService(grpc::AsyncGenericService* service) {
  GPR_ASSERT(service->server_ == nullptr &&
             "Can only register an async generic service against one server.");
  service->server_ = this;
  has_async_generic_service_ = true;
}

void Server::RegisterCallbackGenericService(
    grpc::CallbackGenericService* service) {
  GPR_ASSERT(
      service->server_ == nullptr &&
      "Can only register a callback generic service against one server.");
  service->server_ = this;
  has_callback_generic_service_ = true;
  generic_handler_.reset(service->Handler());

  grpc::CompletionQueue* cq = CallbackCQ();
  server_->core_server->SetBatchMethodAllocator(cq->cq(), [this, cq] {
    grpc_core::Server::BatchCallAllocation result;
    new CallbackRequest<grpc::GenericCallbackServerContext>(this, cq, &result);
    return result;
  });
}

int Server::AddListeningPort(const TString& addr,
                             grpc::ServerCredentials* creds) {
  GPR_ASSERT(!started_);
  int port = creds->AddPortToServer(addr, server_);
  global_callbacks_->AddPort(this, addr, creds, port);
  return port;
}

void Server::Ref() {
  shutdown_refs_outstanding_.fetch_add(1, std::memory_order_relaxed);
}

void Server::UnrefWithPossibleNotify() {
  if (GPR_UNLIKELY(shutdown_refs_outstanding_.fetch_sub(
                       1, std::memory_order_acq_rel) == 1)) {
    // No refs outstanding means that shutdown has been initiated and no more
    // callback requests are outstanding.
    grpc::internal::MutexLock lock(&mu_);
    GPR_ASSERT(shutdown_);
    shutdown_done_ = true;
    shutdown_done_cv_.Signal();
  }
}

void Server::UnrefAndWaitLocked() {
  if (GPR_UNLIKELY(shutdown_refs_outstanding_.fetch_sub(
                       1, std::memory_order_acq_rel) == 1)) {
    shutdown_done_ = true;
    return;  // no need to wait on CV since done condition already set
  }
  shutdown_done_cv_.WaitUntil(&mu_, [this] { return shutdown_done_; });
}

void Server::Start(grpc::ServerCompletionQueue** cqs, size_t num_cqs) {
  GPR_ASSERT(!started_);
  global_callbacks_->PreServerStart(this);
  started_ = true;

  // Only create default health check service when user did not provide an
  // explicit one.
  grpc::ServerCompletionQueue* health_check_cq = nullptr;
  grpc::DefaultHealthCheckService::HealthCheckServiceImpl*
      default_health_check_service_impl = nullptr;
  if (health_check_service_ == nullptr && !health_check_service_disabled_ &&
      grpc::DefaultHealthCheckServiceEnabled()) {
    auto* default_hc_service = new grpc::DefaultHealthCheckService;
    health_check_service_.reset(default_hc_service);
    // We create a non-polling CQ to avoid impacting application
    // performance.  This ensures that we don't introduce thread hops
    // for application requests that wind up on this CQ, which is polled
    // in its own thread.
    health_check_cq = new grpc::ServerCompletionQueue(
        GRPC_CQ_NEXT, GRPC_CQ_NON_POLLING, nullptr);
    grpc_server_register_completion_queue(server_, health_check_cq->cq(),
                                          nullptr);
    default_health_check_service_impl =
        default_hc_service->GetHealthCheckService(
            std::unique_ptr<grpc::ServerCompletionQueue>(health_check_cq));
    RegisterService(nullptr, default_health_check_service_impl);
  }

  for (auto& acceptor : acceptors_) {
    acceptor->GetCredentials()->AddPortToServer(acceptor->name(), server_);
  }

  // If this server uses callback methods, then create a callback generic
  // service to handle any unimplemented methods using the default reactor
  // creator
  if (has_callback_methods_ && !has_callback_generic_service_) {
    unimplemented_service_.reset(new grpc::CallbackGenericService);
    RegisterCallbackGenericService(unimplemented_service_.get());
  }

#ifndef NDEBUG
  for (size_t i = 0; i < num_cqs; i++) {
    cq_list_.push_back(cqs[i]);
  }
#endif

  grpc_server_start(server_);

  if (!has_async_generic_service_ && !has_callback_generic_service_) {
    for (const auto& value : sync_req_mgrs_) {
      value->AddUnknownSyncMethod();
    }

    for (size_t i = 0; i < num_cqs; i++) {
      if (cqs[i]->IsFrequentlyPolled()) {
        new UnimplementedAsyncRequest(this, cqs[i]);
      }
    }
    if (health_check_cq != nullptr) {
      new UnimplementedAsyncRequest(this, health_check_cq);
    }
  }

  // If this server has any support for synchronous methods (has any sync
  // server CQs), make sure that we have a ResourceExhausted handler
  // to deal with the case of thread exhaustion
  if (sync_server_cqs_ != nullptr && !sync_server_cqs_->empty()) {
    resource_exhausted_handler_.reset(
        new grpc::internal::ResourceExhaustedHandler);
  }

  for (const auto& value : sync_req_mgrs_) {
    value->Start();
  }

  if (default_health_check_service_impl != nullptr) {
    default_health_check_service_impl->StartServingThread();
  }

  for (auto& acceptor : acceptors_) {
    acceptor->Start();
  }
}

void Server::ShutdownInternal(gpr_timespec deadline) {
  grpc::internal::MutexLock lock(&mu_);
  if (shutdown_) {
    return;
  }

  shutdown_ = true;

  for (auto& acceptor : acceptors_) {
    acceptor->Shutdown();
  }

  /// The completion queue to use for server shutdown completion notification
  grpc::CompletionQueue shutdown_cq;
  grpc::ShutdownTag shutdown_tag;  // Dummy shutdown tag
  grpc_server_shutdown_and_notify(server_, shutdown_cq.cq(), &shutdown_tag);

  shutdown_cq.Shutdown();

  void* tag;
  bool ok;
  grpc::CompletionQueue::NextStatus status =
      shutdown_cq.AsyncNext(&tag, &ok, deadline);

  // If this timed out, it means we are done with the grace period for a clean
  // shutdown. We should force a shutdown now by cancelling all inflight calls
  if (status == grpc::CompletionQueue::NextStatus::TIMEOUT) {
    grpc_server_cancel_all_calls(server_);
  }
  // Else in case of SHUTDOWN or GOT_EVENT, it means that the server has
  // successfully shutdown

  // Shutdown all ThreadManagers. This will try to gracefully stop all the
  // threads in the ThreadManagers (once they process any inflight requests)
  for (const auto& value : sync_req_mgrs_) {
    value->Shutdown();  // ThreadManager's Shutdown()
  }

  // Wait for threads in all ThreadManagers to terminate
  for (const auto& value : sync_req_mgrs_) {
    value->Wait();
  }

  // Drop the shutdown ref and wait for all other refs to drop as well.
  UnrefAndWaitLocked();

  // Shutdown the callback CQ. The CQ is owned by its own shutdown tag, so it
  // will delete itself at true shutdown.
  if (callback_cq_ != nullptr) {
    callback_cq_->Shutdown();
    callback_cq_ = nullptr;
  }

  // Drain the shutdown queue (if the previous call to AsyncNext() timed out
  // and we didn't remove the tag from the queue yet)
  while (shutdown_cq.Next(&tag, &ok)) {
    // Nothing to be done here. Just ignore ok and tag values
  }

  shutdown_notified_ = true;
  shutdown_cv_.Broadcast();

#ifndef NDEBUG
  // Unregister this server with the CQs passed into it by the user so that
  // those can be checked for properly-ordered shutdown.
  for (auto* cq : cq_list_) {
    cq->UnregisterServer(this);
  }
  cq_list_.clear();
#endif
}

void Server::Wait() {
  grpc::internal::MutexLock lock(&mu_);
  while (started_ && !shutdown_notified_) {
    shutdown_cv_.Wait(&mu_);
  }
}

void Server::PerformOpsOnCall(grpc::internal::CallOpSetInterface* ops,
                              grpc::internal::Call* call) {
  ops->FillOps(call);
}

bool Server::UnimplementedAsyncRequest::FinalizeResult(void** tag,
                                                       bool* status) {
  if (GenericAsyncRequest::FinalizeResult(tag, status)) {
    // We either had no interceptors run or we are done intercepting
    if (*status) {
      // Create a new request/response pair using the server and CQ values
      // stored in this object's base class.
      new UnimplementedAsyncRequest(server_, notification_cq_);
      new UnimplementedAsyncResponse(this);
    } else {
      delete this;
    }
  } else {
    // The tag was swallowed due to interception. We will see it again.
  }
  return false;
}

Server::UnimplementedAsyncResponse::UnimplementedAsyncResponse(
    UnimplementedAsyncRequest* request)
    : request_(request) {
  grpc::Status status(grpc::StatusCode::UNIMPLEMENTED, "");
  grpc::internal::UnknownMethodHandler::FillOps(request_->context(), this);
  request_->stream()->call_.PerformOps(this);
}

grpc::ServerInitializer* Server::initializer() {
  return server_initializer_.get();
}

grpc::CompletionQueue* Server::CallbackCQ() {
  // TODO(vjpai): Consider using a single global CQ for the default CQ
  // if there is no explicit per-server CQ registered
  grpc::internal::MutexLock l(&mu_);
  if (callback_cq_ != nullptr) {
    return callback_cq_;
  }
  auto* shutdown_callback = new grpc::ShutdownCallback;
  callback_cq_ = new grpc::CompletionQueue(grpc_completion_queue_attributes{
      GRPC_CQ_CURRENT_VERSION, GRPC_CQ_CALLBACK, GRPC_CQ_DEFAULT_POLLING,
      shutdown_callback});

  // Transfer ownership of the new cq to its own shutdown callback
  shutdown_callback->TakeCQ(callback_cq_);

  return callback_cq_;
}

}  // namespace grpc