aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/cpp/server/server_cc.cc
blob: 6480482774ee46229b990212d597b1e30fdbe768 (plain)
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
/*
 * 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 <grpc++/server.h>

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

#include <grpc++/completion_queue.h>
#include <grpc++/generic/async_generic_service.h>
#include <grpc++/impl/codegen/async_unary_call.h>
#include <grpc++/impl/codegen/completion_queue_tag.h>
#include <grpc++/impl/grpc_library.h>
#include <grpc++/impl/method_handler_impl.h>
#include <grpc++/impl/rpc_service_method.h>
#include <grpc++/impl/server_initializer.h>
#include <grpc++/impl/service_type.h>
#include <grpc++/security/server_credentials.h>
#include <grpc++/server_context.h>
#include <grpc++/support/time.h>
#include <grpc/grpc.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>

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

namespace grpc {

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

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

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

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

  GenericServerContext server_context_;
  GenericServerAsyncReaderWriter generic_stream_;
};

class Server::UnimplementedAsyncRequest final
    : public UnimplementedAsyncRequestContext,
      public GenericAsyncRequest {
 public:
  UnimplementedAsyncRequest(Server* server, ServerCompletionQueue* cq)
      : GenericAsyncRequest(server, &server_context_, &generic_stream_, cq, cq,
                            NULL, false),
        server_(server),
        cq_(cq) {}

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

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

 private:
  Server* const server_;
  ServerCompletionQueue* const cq_;
};

typedef internal::SneakyCallOpSet<internal::CallOpSendInitialMetadata,
                                  internal::CallOpServerSendStatus>
    UnimplementedAsyncResponseOp;
class Server::UnimplementedAsyncResponse final
    : public UnimplementedAsyncResponseOp {
 public:
  UnimplementedAsyncResponse(UnimplementedAsyncRequest* request);
  ~UnimplementedAsyncResponse() { delete request_; }

  bool FinalizeResult(void** tag, bool* status) override {
    bool r = UnimplementedAsyncResponseOp::FinalizeResult(tag, status);
    delete this;
    return r;
  }

 private:
  UnimplementedAsyncRequest* const request_;
};

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) {
    *status = true;
    return true;
  }
};

class Server::SyncRequest final : public internal::CompletionQueueTag {
 public:
  SyncRequest(internal::RpcServiceMethod* method, void* tag)
      : method_(method),
        tag_(tag),
        in_flight_(false),
        has_request_payload_(
            method->method_type() == internal::RpcMethod::NORMAL_RPC ||
            method->method_type() == 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 (tag_) {
      if (GRPC_CALL_OK !=
          grpc_server_request_registered_call(
              server, tag_, &call_, &deadline_, &request_metadata_,
              has_request_payload_ ? &request_payload_ : nullptr, cq_,
              notify_cq, this)) {
        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;
      }
    }
  }

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

  class CallData final {
   public:
    explicit CallData(Server* server, SyncRequest* mrd)
        : cq_(mrd->cq_),
          call_(mrd->call_, server, &cq_, server->max_receive_message_size()),
          ctx_(mrd->deadline_, &mrd->request_metadata_),
          has_request_payload_(mrd->has_request_payload_),
          request_payload_(mrd->request_payload_),
          method_(mrd->method_) {
      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(std::shared_ptr<GlobalCallbacks> global_callbacks) {
      ctx_.BeginCompletionOp(&call_);
      global_callbacks->PreSynchronousRequest(&ctx_);
      method_->handler()->RunHandler(internal::MethodHandler::HandlerParameter(
          &call_, &ctx_, request_payload_));
      global_callbacks->PostSynchronousRequest(&ctx_);
      request_payload_ = nullptr;

      cq_.Shutdown();

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

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

   private:
    CompletionQueue cq_;
    internal::Call call_;
    ServerContext ctx_;
    const bool has_request_payload_;
    grpc_byte_buffer* request_payload_;
    internal::RpcServiceMethod* const method_;
  };

 private:
  internal::RpcServiceMethod* const method_;
  void* const 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_;
};

// 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 ThreadManager {
 public:
  SyncRequestThreadManager(Server* server, CompletionQueue* server_cq,
                           std::shared_ptr<GlobalCallbacks> global_callbacks,
                           int min_pollers, int max_pollers,
                           int cq_timeout_msec)
      : ThreadManager(min_pollers, max_pollers),
        server_(server),
        server_cq_(server_cq),
        cq_timeout_msec_(cq_timeout_msec),
        global_callbacks_(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 CompletionQueue::TIMEOUT:
        return TIMEOUT;
      case CompletionQueue::SHUTDOWN:
        return SHUTDOWN;
      case CompletionQueue::GOT_EVENT:
        return WORK_FOUND;
    }

    GPR_UNREACHABLE_CODE(return TIMEOUT);
  }

  void DoWork(void* tag, bool ok) 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 inside sync_req
      SyncRequest::CallData cd(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_);
    }
    // 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(internal::RpcServiceMethod* method, void* tag) {
    sync_requests_.emplace_back(new SyncRequest(method, tag));
  }

  void AddUnknownSyncMethod() {
    if (!sync_requests_.empty()) {
      unknown_method_.reset(new internal::RpcServiceMethod(
          "unknown", internal::RpcMethod::BIDI_STREAMING,
          new 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)) {
      // Do nothing
    }
  }

  void Start() {
    if (!sync_requests_.empty()) {
      for (auto m = sync_requests_.begin(); m != sync_requests_.end(); m++) {
        (*m)->SetupRequest();
        (*m)->Request(server_->c_server(), server_cq_->cq());
      }

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

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

static internal::GrpcLibraryInitializer g_gli_initializer;
Server::Server(
    int max_receive_message_size, ChannelArguments* args,
    std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
        sync_server_cqs,
    int min_pollers, int max_pollers, int sync_cq_timeout_msec)
    : max_receive_message_size_(max_receive_message_size),
      sync_server_cqs_(sync_server_cqs),
      started_(false),
      shutdown_(false),
      shutdown_notified_(false),
      has_generic_service_(false),
      server_(nullptr),
      server_initializer_(new ServerInitializer(this)),
      health_check_service_disabled_(false) {
  g_gli_initializer.summon();
  gpr_once_init(&g_once_init_callbacks, InitGlobalCallbacks);
  global_callbacks_ = g_callbacks;
  global_callbacks_->UpdateArguments(args);

  for (auto it = sync_server_cqs_->begin(); it != sync_server_cqs_->end();
       it++) {
    sync_req_mgrs_.emplace_back(new SyncRequestThreadManager(
        this, (*it).get(), global_callbacks_, min_pollers, max_pollers,
        sync_cq_timeout_msec));
  }

  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, kHealthCheckServiceInterfaceArg)) {
      if (channel_args.args[i].value.pointer.p == nullptr) {
        health_check_service_disabled_ = true;
      } else {
        health_check_service_.reset(static_cast<HealthCheckServiceInterface*>(
            channel_args.args[i].value.pointer.p));
      }
      break;
    }
  }

  server_ = grpc_server_create(&channel_args, nullptr);
}

Server::~Server() {
  {
    std::unique_lock<std::mutex> lock(mu_);
    if (started_ && !shutdown_) {
      lock.unlock();
      Shutdown();
    } else if (!started_) {
      // Shutdown the completion queues
      for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
        (*it)->Shutdown();
      }
    }
  }

  grpc_server_destroy(server_);
}

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

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

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

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

bool Server::RegisterService(const grpc::string* host, 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 (auto it = service->methods_.begin(); it != service->methods_.end();
       ++it) {
    if (it->get() == nullptr) {  // Handled by generic service if any.
      continue;
    }

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

    if (method->handler() == nullptr) {  // Async method
      method->set_server_tag(tag);
    } else {
      for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
        (*it)->AddSyncMethod(method, tag);
      }
    }

    method_name = method->name();
  }

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

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

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

void Server::Start(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.
  if (health_check_service_ == nullptr && !health_check_service_disabled_ &&
      DefaultHealthCheckServiceEnabled()) {
    if (sync_server_cqs_->empty()) {
      gpr_log(GPR_INFO,
              "Default health check service disabled at async-only server.");
    } else {
      auto* default_hc_service = new DefaultHealthCheckService;
      health_check_service_.reset(default_hc_service);
      RegisterService(nullptr, default_hc_service->GetHealthCheckService());
    }
  }

  grpc_server_start(server_);

  if (!has_generic_service_) {
    for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
      (*it)->AddUnknownSyncMethod();
    }

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

  for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
    (*it)->Start();
  }
}

void Server::ShutdownInternal(gpr_timespec deadline) {
  std::unique_lock<std::mutex> lock(mu_);
  if (!shutdown_) {
    shutdown_ = true;

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

    shutdown_cq.Shutdown();

    void* tag;
    bool ok;
    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 == 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 (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
      (*it)->Shutdown();  // ThreadManager's Shutdown()
    }

    // Wait for threads in all ThreadManagers to terminate
    for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
      (*it)->Wait();
    }

    // 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_.notify_all();
  }
}

void Server::Wait() {
  std::unique_lock<std::mutex> lock(mu_);
  while (started_ && !shutdown_notified_) {
    shutdown_cv_.wait(lock);
  }
}

void Server::PerformOpsOnCall(internal::CallOpSetInterface* ops,
                              internal::Call* call) {
  static const size_t MAX_OPS = 8;
  size_t nops = 0;
  grpc_op cops[MAX_OPS];
  ops->FillOps(call->call(), cops, &nops);
  auto result = grpc_call_start_batch(call->call(), cops, nops, ops, nullptr);
  if (result != GRPC_CALL_OK) {
    gpr_log(GPR_ERROR, "Fatal: grpc_call_start_batch returned %d", result);
    grpc_call_log_batch(__FILE__, __LINE__, GPR_LOG_SEVERITY_ERROR,
                        call->call(), cops, nops, ops);
    abort();
  }
}

ServerInterface::BaseAsyncRequest::BaseAsyncRequest(
    ServerInterface* server, ServerContext* context,
    internal::ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
    void* tag, bool delete_on_finalize)
    : server_(server),
      context_(context),
      stream_(stream),
      call_cq_(call_cq),
      tag_(tag),
      delete_on_finalize_(delete_on_finalize),
      call_(nullptr) {
  call_cq_->RegisterAvalanching();  // This op will trigger more ops
}

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

bool ServerInterface::BaseAsyncRequest::FinalizeResult(void** tag,
                                                       bool* status) {
  if (*status) {
    context_->client_metadata_.FillMap();
  }
  context_->set_call(call_);
  context_->cq_ = call_cq_;
  internal::Call call(call_, server_, call_cq_,
                      server_->max_receive_message_size());
  if (*status && call_) {
    context_->BeginCompletionOp(&call);
  }
  // just the pointers inside call are copied here
  stream_->BindCall(&call);
  *tag = tag_;
  if (delete_on_finalize_) {
    delete this;
  }
  return true;
}

ServerInterface::RegisteredAsyncRequest::RegisteredAsyncRequest(
    ServerInterface* server, ServerContext* context,
    internal::ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
    void* tag)
    : BaseAsyncRequest(server, context, stream, call_cq, tag, true) {}

void ServerInterface::RegisteredAsyncRequest::IssueRequest(
    void* registered_method, grpc_byte_buffer** payload,
    ServerCompletionQueue* notification_cq) {
  GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_registered_call(
                                 server_->server(), registered_method, &call_,
                                 &context_->deadline_,
                                 context_->client_metadata_.arr(), payload,
                                 call_cq_->cq(), notification_cq->cq(), this));
}

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, tag,
                       delete_on_finalize) {
  grpc_call_details_init(&call_details_);
  GPR_ASSERT(notification_cq);
  GPR_ASSERT(call_cq);
  GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(
                                 server->server(), &call_, &call_details_,
                                 context->client_metadata_.arr(), call_cq->cq(),
                                 notification_cq->cq(), this));
}

bool ServerInterface::GenericAsyncRequest::FinalizeResult(void** tag,
                                                          bool* 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);
  return BaseAsyncRequest::FinalizeResult(tag, status);
}

bool Server::UnimplementedAsyncRequest::FinalizeResult(void** tag,
                                                       bool* status) {
  if (GenericAsyncRequest::FinalizeResult(tag, status) && *status) {
    new UnimplementedAsyncRequest(server_, cq_);
    new UnimplementedAsyncResponse(this);
  } else {
    delete this;
  }
  return false;
}

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

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

}  // namespace grpc