/*
 *
 * Copyright 2015-2016, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <memory>
#include <thread>

#include <grpc++/channel.h>
#include <grpc++/client_context.h>
#include <grpc++/create_channel.h>
#include <grpc++/server.h>
#include <grpc++/server_builder.h>
#include <grpc++/server_context.h>
#include <grpc/grpc.h>
#include <grpc/support/thd.h>
#include <grpc/support/time.h>
#include <gtest/gtest.h>

#include "src/proto/grpc/testing/duplicate/echo_duplicate.grpc.pb.h"
#include "src/proto/grpc/testing/echo.grpc.pb.h"
#include "test/core/util/port.h"
#include "test/core/util/test_config.h"
#include "test/cpp/util/string_ref_helper.h"

#ifdef GPR_POSIX_SOCKET
#include "src/core/iomgr/pollset_posix.h"
#endif

using grpc::testing::EchoRequest;
using grpc::testing::EchoResponse;
using std::chrono::system_clock;

namespace grpc {
namespace testing {

namespace {

void* tag(int i) { return (void*)(intptr_t)i; }

#ifdef GPR_POSIX_SOCKET
static int assert_non_blocking_poll(struct pollfd* pfds, nfds_t nfds,
                                    int timeout) {
  GPR_ASSERT(timeout == 0);
  return poll(pfds, nfds, timeout);
}

class PollOverride {
 public:
  PollOverride(grpc_poll_function_type f) {
    prev_ = grpc_poll_function;
    grpc_poll_function = f;
  }

  ~PollOverride() { grpc_poll_function = prev_; }

 private:
  grpc_poll_function_type prev_;
};

class PollingCheckRegion : public PollOverride {
 public:
  explicit PollingCheckRegion(bool allow_blocking)
      : PollOverride(allow_blocking ? poll : assert_non_blocking_poll) {}
};
#else
class PollingCheckRegion {
 public:
  explicit PollingCheckRegion(bool allow_blocking) {}
};
#endif

class Verifier : public PollingCheckRegion {
 public:
  explicit Verifier(bool spin) : PollingCheckRegion(!spin), spin_(spin) {}
  Verifier& Expect(int i, bool expect_ok) {
    expectations_[tag(i)] = expect_ok;
    return *this;
  }

  void Verify(CompletionQueue* cq) { Verify(cq, false); }

  void Verify(CompletionQueue* cq, bool ignore_ok) {
    GPR_ASSERT(!expectations_.empty());
    while (!expectations_.empty()) {
      bool ok;
      void* got_tag;
      if (spin_) {
        for (;;) {
          auto r = cq->AsyncNext(&got_tag, &ok, gpr_time_0(GPR_CLOCK_REALTIME));
          if (r == CompletionQueue::TIMEOUT) continue;
          if (r == CompletionQueue::GOT_EVENT) break;
          gpr_log(GPR_ERROR, "unexpected result from AsyncNext");
          abort();
        }
      } else {
        EXPECT_TRUE(cq->Next(&got_tag, &ok));
      }
      auto it = expectations_.find(got_tag);
      EXPECT_TRUE(it != expectations_.end());
      if (!ignore_ok) {
        EXPECT_EQ(it->second, ok);
      }
      expectations_.erase(it);
    }
  }
  void Verify(CompletionQueue* cq,
              std::chrono::system_clock::time_point deadline) {
    if (expectations_.empty()) {
      bool ok;
      void* got_tag;
      if (spin_) {
        while (std::chrono::system_clock::now() < deadline) {
          EXPECT_EQ(
              cq->AsyncNext(&got_tag, &ok, gpr_time_0(GPR_CLOCK_REALTIME)),
              CompletionQueue::TIMEOUT);
        }
      } else {
        EXPECT_EQ(cq->AsyncNext(&got_tag, &ok, deadline),
                  CompletionQueue::TIMEOUT);
      }
    } else {
      while (!expectations_.empty()) {
        bool ok;
        void* got_tag;
        if (spin_) {
          for (;;) {
            GPR_ASSERT(std::chrono::system_clock::now() < deadline);
            auto r =
                cq->AsyncNext(&got_tag, &ok, gpr_time_0(GPR_CLOCK_REALTIME));
            if (r == CompletionQueue::TIMEOUT) continue;
            if (r == CompletionQueue::GOT_EVENT) break;
            gpr_log(GPR_ERROR, "unexpected result from AsyncNext");
            abort();
          }
        } else {
          EXPECT_EQ(cq->AsyncNext(&got_tag, &ok, deadline),
                    CompletionQueue::GOT_EVENT);
        }
        auto it = expectations_.find(got_tag);
        EXPECT_TRUE(it != expectations_.end());
        EXPECT_EQ(it->second, ok);
        expectations_.erase(it);
      }
    }
  }

 private:
  std::map<void*, bool> expectations_;
  bool spin_;
};

class AsyncEnd2endTest : public ::testing::TestWithParam<bool> {
 protected:
  AsyncEnd2endTest() {}

  void SetUp() GRPC_OVERRIDE {
    int port = grpc_pick_unused_port_or_die();
    server_address_ << "localhost:" << port;

    // Setup server
    ServerBuilder builder;
    builder.AddListeningPort(server_address_.str(),
                             grpc::InsecureServerCredentials());
    builder.RegisterService(&service_);
    cq_ = builder.AddCompletionQueue();
    server_ = builder.BuildAndStart();
  }

  void TearDown() GRPC_OVERRIDE {
    server_->Shutdown();
    void* ignored_tag;
    bool ignored_ok;
    cq_->Shutdown();
    while (cq_->Next(&ignored_tag, &ignored_ok))
      ;
  }

  void ResetStub() {
    std::shared_ptr<Channel> channel =
        CreateChannel(server_address_.str(), InsecureChannelCredentials());
    stub_ = grpc::testing::EchoTestService::NewStub(channel);
  }

  void SendRpc(int num_rpcs) {
    for (int i = 0; i < num_rpcs; i++) {
      EchoRequest send_request;
      EchoRequest recv_request;
      EchoResponse send_response;
      EchoResponse recv_response;
      Status recv_status;

      ClientContext cli_ctx;
      ServerContext srv_ctx;
      grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

      send_request.set_message("Hello");
      std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
          stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

      service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                           cq_.get(), tag(2));

      Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
      EXPECT_EQ(send_request.message(), recv_request.message());

      send_response.set_message(recv_request.message());
      response_writer.Finish(send_response, Status::OK, tag(3));
      Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

      response_reader->Finish(&recv_response, &recv_status, tag(4));
      Verifier(GetParam()).Expect(4, true).Verify(cq_.get());

      EXPECT_EQ(send_response.message(), recv_response.message());
      EXPECT_TRUE(recv_status.ok());
    }
  }

  std::unique_ptr<ServerCompletionQueue> cq_;
  std::unique_ptr<grpc::testing::EchoTestService::Stub> stub_;
  std::unique_ptr<Server> server_;
  grpc::testing::EchoTestService::AsyncService service_;
  std::ostringstream server_address_;
};

TEST_P(AsyncEnd2endTest, SimpleRpc) {
  ResetStub();
  SendRpc(1);
}

TEST_P(AsyncEnd2endTest, SequentialRpcs) {
  ResetStub();
  SendRpc(10);
}

// Test a simple RPC using the async version of Next
TEST_P(AsyncEnd2endTest, AsyncNextRpc) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  std::chrono::system_clock::time_point time_now(
      std::chrono::system_clock::now());
  std::chrono::system_clock::time_point time_limit(
      std::chrono::system_clock::now() + std::chrono::seconds(10));
  Verifier(GetParam()).Verify(cq_.get(), time_now);
  Verifier(GetParam()).Verify(cq_.get(), time_now);

  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));

  Verifier(GetParam()).Expect(2, true).Verify(cq_.get(), time_limit);
  EXPECT_EQ(send_request.message(), recv_request.message());

  send_response.set_message(recv_request.message());
  response_writer.Finish(send_response, Status::OK, tag(3));
  Verifier(GetParam())
      .Expect(3, true)
      .Verify(cq_.get(), std::chrono::system_clock::time_point::max());

  response_reader->Finish(&recv_response, &recv_status, tag(4));
  Verifier(GetParam())
      .Expect(4, true)
      .Verify(cq_.get(), std::chrono::system_clock::time_point::max());

  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
}

// Two pings and a final pong.
TEST_P(AsyncEnd2endTest, SimpleClientStreaming) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;
  ClientContext cli_ctx;
  ServerContext srv_ctx;
  ServerAsyncReader<EchoResponse, EchoRequest> srv_stream(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncWriter<EchoRequest>> cli_stream(
      stub_->AsyncRequestStream(&cli_ctx, &recv_response, cq_.get(), tag(1)));

  service_.RequestRequestStream(&srv_ctx, &srv_stream, cq_.get(), cq_.get(),
                                tag(2));

  Verifier(GetParam()).Expect(2, true).Expect(1, true).Verify(cq_.get());

  cli_stream->Write(send_request, tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  srv_stream.Read(&recv_request, tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());

  cli_stream->Write(send_request, tag(5));
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());

  srv_stream.Read(&recv_request, tag(6));
  Verifier(GetParam()).Expect(6, true).Verify(cq_.get());

  EXPECT_EQ(send_request.message(), recv_request.message());
  cli_stream->WritesDone(tag(7));
  Verifier(GetParam()).Expect(7, true).Verify(cq_.get());

  srv_stream.Read(&recv_request, tag(8));
  Verifier(GetParam()).Expect(8, false).Verify(cq_.get());

  send_response.set_message(recv_request.message());
  srv_stream.Finish(send_response, Status::OK, tag(9));
  Verifier(GetParam()).Expect(9, true).Verify(cq_.get());

  cli_stream->Finish(&recv_status, tag(10));
  Verifier(GetParam()).Expect(10, true).Verify(cq_.get());

  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
}

// One ping, two pongs.
TEST_P(AsyncEnd2endTest, SimpleServerStreaming) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;
  ClientContext cli_ctx;
  ServerContext srv_ctx;
  ServerAsyncWriter<EchoResponse> srv_stream(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncReader<EchoResponse>> cli_stream(
      stub_->AsyncResponseStream(&cli_ctx, send_request, cq_.get(), tag(1)));

  service_.RequestResponseStream(&srv_ctx, &recv_request, &srv_stream,
                                 cq_.get(), cq_.get(), tag(2));

  Verifier(GetParam()).Expect(1, true).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());

  send_response.set_message(recv_request.message());
  srv_stream.Write(send_response, tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  cli_stream->Read(&recv_response, tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
  EXPECT_EQ(send_response.message(), recv_response.message());

  srv_stream.Write(send_response, tag(5));
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());

  cli_stream->Read(&recv_response, tag(6));
  Verifier(GetParam()).Expect(6, true).Verify(cq_.get());
  EXPECT_EQ(send_response.message(), recv_response.message());

  srv_stream.Finish(Status::OK, tag(7));
  Verifier(GetParam()).Expect(7, true).Verify(cq_.get());

  cli_stream->Read(&recv_response, tag(8));
  Verifier(GetParam()).Expect(8, false).Verify(cq_.get());

  cli_stream->Finish(&recv_status, tag(9));
  Verifier(GetParam()).Expect(9, true).Verify(cq_.get());

  EXPECT_TRUE(recv_status.ok());
}

// One ping, one pong.
TEST_P(AsyncEnd2endTest, SimpleBidiStreaming) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;
  ClientContext cli_ctx;
  ServerContext srv_ctx;
  ServerAsyncReaderWriter<EchoResponse, EchoRequest> srv_stream(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncReaderWriter<EchoRequest, EchoResponse>>
      cli_stream(stub_->AsyncBidiStream(&cli_ctx, cq_.get(), tag(1)));

  service_.RequestBidiStream(&srv_ctx, &srv_stream, cq_.get(), cq_.get(),
                             tag(2));

  Verifier(GetParam()).Expect(1, true).Expect(2, true).Verify(cq_.get());

  cli_stream->Write(send_request, tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  srv_stream.Read(&recv_request, tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());

  send_response.set_message(recv_request.message());
  srv_stream.Write(send_response, tag(5));
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());

  cli_stream->Read(&recv_response, tag(6));
  Verifier(GetParam()).Expect(6, true).Verify(cq_.get());
  EXPECT_EQ(send_response.message(), recv_response.message());

  cli_stream->WritesDone(tag(7));
  Verifier(GetParam()).Expect(7, true).Verify(cq_.get());

  srv_stream.Read(&recv_request, tag(8));
  Verifier(GetParam()).Expect(8, false).Verify(cq_.get());

  srv_stream.Finish(Status::OK, tag(9));
  Verifier(GetParam()).Expect(9, true).Verify(cq_.get());

  cli_stream->Finish(&recv_status, tag(10));
  Verifier(GetParam()).Expect(10, true).Verify(cq_.get());

  EXPECT_TRUE(recv_status.ok());
}

// Metadata tests
TEST_P(AsyncEnd2endTest, ClientInitialMetadataRpc) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::pair<grpc::string, grpc::string> meta1("key1", "val1");
  std::pair<grpc::string, grpc::string> meta2("key2", "val2");
  std::pair<grpc::string, grpc::string> meta3("g.r.d-bin", "xyz");
  cli_ctx.AddMetadata(meta1.first, meta1.second);
  cli_ctx.AddMetadata(meta2.first, meta2.second);
  cli_ctx.AddMetadata(meta3.first, meta3.second);

  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));
  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());
  auto client_initial_metadata = srv_ctx.client_metadata();
  EXPECT_EQ(meta1.second,
            ToString(client_initial_metadata.find(meta1.first)->second));
  EXPECT_EQ(meta2.second,
            ToString(client_initial_metadata.find(meta2.first)->second));
  EXPECT_EQ(meta3.second,
            ToString(client_initial_metadata.find(meta3.first)->second));
  EXPECT_GE(client_initial_metadata.size(), static_cast<size_t>(2));

  send_response.set_message(recv_request.message());
  response_writer.Finish(send_response, Status::OK, tag(3));

  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  response_reader->Finish(&recv_response, &recv_status, tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());

  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
}

TEST_P(AsyncEnd2endTest, ServerInitialMetadataRpc) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::pair<grpc::string, grpc::string> meta1("key1", "val1");
  std::pair<grpc::string, grpc::string> meta2("key2", "val2");

  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));
  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());
  srv_ctx.AddInitialMetadata(meta1.first, meta1.second);
  srv_ctx.AddInitialMetadata(meta2.first, meta2.second);
  response_writer.SendInitialMetadata(tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  response_reader->ReadInitialMetadata(tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
  auto server_initial_metadata = cli_ctx.GetServerInitialMetadata();
  EXPECT_EQ(meta1.second,
            ToString(server_initial_metadata.find(meta1.first)->second));
  EXPECT_EQ(meta2.second,
            ToString(server_initial_metadata.find(meta2.first)->second));
  EXPECT_EQ(static_cast<size_t>(2), server_initial_metadata.size());

  send_response.set_message(recv_request.message());
  response_writer.Finish(send_response, Status::OK, tag(5));
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());

  response_reader->Finish(&recv_response, &recv_status, tag(6));
  Verifier(GetParam()).Expect(6, true).Verify(cq_.get());

  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
}

TEST_P(AsyncEnd2endTest, ServerTrailingMetadataRpc) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::pair<grpc::string, grpc::string> meta1("key1", "val1");
  std::pair<grpc::string, grpc::string> meta2("key2", "val2");

  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));
  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());
  response_writer.SendInitialMetadata(tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

  send_response.set_message(recv_request.message());
  srv_ctx.AddTrailingMetadata(meta1.first, meta1.second);
  srv_ctx.AddTrailingMetadata(meta2.first, meta2.second);
  response_writer.Finish(send_response, Status::OK, tag(4));

  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());

  response_reader->Finish(&recv_response, &recv_status, tag(5));
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());
  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
  auto server_trailing_metadata = cli_ctx.GetServerTrailingMetadata();
  EXPECT_EQ(meta1.second,
            ToString(server_trailing_metadata.find(meta1.first)->second));
  EXPECT_EQ(meta2.second,
            ToString(server_trailing_metadata.find(meta2.first)->second));
  EXPECT_EQ(static_cast<size_t>(2), server_trailing_metadata.size());
}

TEST_P(AsyncEnd2endTest, MetadataRpc) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::pair<grpc::string, grpc::string> meta1("key1", "val1");
  std::pair<grpc::string, grpc::string> meta2(
      "key2-bin",
      grpc::string("\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc", 13));
  std::pair<grpc::string, grpc::string> meta3("key3", "val3");
  std::pair<grpc::string, grpc::string> meta6(
      "key4-bin",
      grpc::string("\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d",
                   14));
  std::pair<grpc::string, grpc::string> meta5("key5", "val5");
  std::pair<grpc::string, grpc::string> meta4(
      "key6-bin",
      grpc::string(
          "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee", 15));

  cli_ctx.AddMetadata(meta1.first, meta1.second);
  cli_ctx.AddMetadata(meta2.first, meta2.second);

  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));
  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());
  auto client_initial_metadata = srv_ctx.client_metadata();
  EXPECT_EQ(meta1.second,
            ToString(client_initial_metadata.find(meta1.first)->second));
  EXPECT_EQ(meta2.second,
            ToString(client_initial_metadata.find(meta2.first)->second));
  EXPECT_GE(client_initial_metadata.size(), static_cast<size_t>(2));

  srv_ctx.AddInitialMetadata(meta3.first, meta3.second);
  srv_ctx.AddInitialMetadata(meta4.first, meta4.second);
  response_writer.SendInitialMetadata(tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());
  response_reader->ReadInitialMetadata(tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());
  auto server_initial_metadata = cli_ctx.GetServerInitialMetadata();
  EXPECT_EQ(meta3.second,
            ToString(server_initial_metadata.find(meta3.first)->second));
  EXPECT_EQ(meta4.second,
            ToString(server_initial_metadata.find(meta4.first)->second));
  EXPECT_GE(server_initial_metadata.size(), static_cast<size_t>(2));

  send_response.set_message(recv_request.message());
  srv_ctx.AddTrailingMetadata(meta5.first, meta5.second);
  srv_ctx.AddTrailingMetadata(meta6.first, meta6.second);
  response_writer.Finish(send_response, Status::OK, tag(5));

  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());

  response_reader->Finish(&recv_response, &recv_status, tag(6));
  Verifier(GetParam()).Expect(6, true).Verify(cq_.get());
  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
  auto server_trailing_metadata = cli_ctx.GetServerTrailingMetadata();
  EXPECT_EQ(meta5.second,
            ToString(server_trailing_metadata.find(meta5.first)->second));
  EXPECT_EQ(meta6.second,
            ToString(server_trailing_metadata.find(meta6.first)->second));
  EXPECT_GE(server_trailing_metadata.size(), static_cast<size_t>(2));
}

// Server uses AsyncNotifyWhenDone API to check for cancellation
TEST_P(AsyncEnd2endTest, ServerCheckCancellation) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  srv_ctx.AsyncNotifyWhenDone(tag(5));
  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));

  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());

  cli_ctx.TryCancel();
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());
  EXPECT_TRUE(srv_ctx.IsCancelled());

  response_reader->Finish(&recv_response, &recv_status, tag(4));
  Verifier(GetParam()).Expect(4, false).Verify(cq_.get());

  EXPECT_EQ(StatusCode::CANCELLED, recv_status.error_code());
}

// Server uses AsyncNotifyWhenDone API to check for normal finish
TEST_P(AsyncEnd2endTest, ServerCheckDone) {
  ResetStub();

  EchoRequest send_request;
  EchoRequest recv_request;
  EchoResponse send_response;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  ServerContext srv_ctx;
  grpc::ServerAsyncResponseWriter<EchoResponse> response_writer(&srv_ctx);

  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub_->AsyncEcho(&cli_ctx, send_request, cq_.get()));

  srv_ctx.AsyncNotifyWhenDone(tag(5));
  service_.RequestEcho(&srv_ctx, &recv_request, &response_writer, cq_.get(),
                       cq_.get(), tag(2));

  Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
  EXPECT_EQ(send_request.message(), recv_request.message());

  send_response.set_message(recv_request.message());
  response_writer.Finish(send_response, Status::OK, tag(3));
  Verifier(GetParam()).Expect(3, true).Verify(cq_.get());
  Verifier(GetParam()).Expect(5, true).Verify(cq_.get());
  EXPECT_FALSE(srv_ctx.IsCancelled());

  response_reader->Finish(&recv_response, &recv_status, tag(4));
  Verifier(GetParam()).Expect(4, true).Verify(cq_.get());

  EXPECT_EQ(send_response.message(), recv_response.message());
  EXPECT_TRUE(recv_status.ok());
}

TEST_P(AsyncEnd2endTest, UnimplementedRpc) {
  std::shared_ptr<Channel> channel =
      CreateChannel(server_address_.str(), InsecureChannelCredentials());
  std::unique_ptr<grpc::testing::UnimplementedService::Stub> stub;
  stub = grpc::testing::UnimplementedService::NewStub(channel);
  EchoRequest send_request;
  EchoResponse recv_response;
  Status recv_status;

  ClientContext cli_ctx;
  send_request.set_message("Hello");
  std::unique_ptr<ClientAsyncResponseReader<EchoResponse>> response_reader(
      stub->AsyncUnimplemented(&cli_ctx, send_request, cq_.get()));

  response_reader->Finish(&recv_response, &recv_status, tag(4));
  Verifier(GetParam()).Expect(4, false).Verify(cq_.get());

  EXPECT_EQ(StatusCode::UNIMPLEMENTED, recv_status.error_code());
  EXPECT_EQ("", recv_status.error_message());
}

// This class is for testing scenarios where RPCs are cancelled on the server
// by calling ServerContext::TryCancel()
class AsyncEnd2endServerTryCancelTest : public AsyncEnd2endTest {
 protected:
  typedef enum {
    DO_NOT_CANCEL = 0,
    CANCEL_BEFORE_PROCESSING,
    CANCEL_DURING_PROCESSING,
    CANCEL_AFTER_PROCESSING
  } ServerTryCancelRequestPhase;

  void ServerTryCancel(ServerContext* context) {
    EXPECT_FALSE(context->IsCancelled());
    context->TryCancel();
    gpr_log(GPR_INFO, "Server called TryCancel()");
    EXPECT_TRUE(context->IsCancelled());
  }

  // Helper for testing client-streaming RPCs which are cancelled on the server.
  // Depending on the value of server_try_cancel parameter, this will test one
  // of the following three scenarios:
  //   CANCEL_BEFORE_PROCESSING: Rpc is cancelled by the server before reading
  //   any messages from the client
  //
  //   CANCEL_DURING_PROCESSING: Rpc is cancelled by the server while reading
  //   messages from the client
  //
  //   CANCEL_AFTER PROCESSING: Rpc is cancelled by server after reading all
  //   messages from the client (but before sending any status back to the
  //   client)
  void TestClientStreamingServerCancel(
      ServerTryCancelRequestPhase server_try_cancel) {
    ResetStub();

    EchoRequest send_request;
    EchoRequest recv_request;
    EchoResponse send_response;
    EchoResponse recv_response;
    Status recv_status;

    ClientContext cli_ctx;
    ServerContext srv_ctx;
    ServerAsyncReader<EchoResponse, EchoRequest> srv_stream(&srv_ctx);

    // Initiate the 'RequestStream' call on client
    std::unique_ptr<ClientAsyncWriter<EchoRequest>> cli_stream(
        stub_->AsyncRequestStream(&cli_ctx, &recv_response, cq_.get(), tag(1)));
    Verifier(GetParam()).Expect(1, true).Verify(cq_.get());

    // On the server, request to be notified of 'RequestStream' calls
    // and receive the 'RequestStream' call just made by the client
    service_.RequestRequestStream(&srv_ctx, &srv_stream, cq_.get(), cq_.get(),
                                  tag(2));
    Verifier(GetParam()).Expect(2, true).Verify(cq_.get());

    // Client sends 3 messages (tags 3, 4 and 5)
    for (int tag_idx = 3; tag_idx <= 5; tag_idx++) {
      send_request.set_message("Ping " + std::to_string(tag_idx));
      cli_stream->Write(send_request, tag(tag_idx));
      Verifier(GetParam()).Expect(tag_idx, true).Verify(cq_.get());
    }
    cli_stream->WritesDone(tag(6));
    Verifier(GetParam()).Expect(6, true).Verify(cq_.get());

    bool expected_server_cq_result = true;
    bool ignore_cq_result = false;

    if (server_try_cancel == CANCEL_BEFORE_PROCESSING) {
      ServerTryCancel(&srv_ctx);

      // Since cancellation is done before server reads any results, we know
      // for sure that all cq results will return false from this point forward
      expected_server_cq_result = false;
    }

    std::thread* server_try_cancel_thd = NULL;
    if (server_try_cancel == CANCEL_DURING_PROCESSING) {
      server_try_cancel_thd = new std::thread(
          &AsyncEnd2endServerTryCancelTest::ServerTryCancel, this, &srv_ctx);
      // Server will cancel the RPC in a parallel thread while reading the
      // requests from the client. Since the cancellation can happen at anytime,
      // some of the cq results (i.e those until cancellation) might be true but
      // its non deterministic. So better to ignore the cq results
      ignore_cq_result = true;
    }

    // Server reads 3 messages (tags 6, 7 and 8)
    for (int tag_idx = 6; tag_idx <= 8; tag_idx++) {
      srv_stream.Read(&recv_request, tag(tag_idx));
      Verifier(GetParam())
          .Expect(tag_idx, expected_server_cq_result)
          .Verify(cq_.get(), ignore_cq_result);
    }

    if (server_try_cancel_thd != NULL) {
      server_try_cancel_thd->join();
      delete server_try_cancel_thd;
    }

    if (server_try_cancel == CANCEL_AFTER_PROCESSING) {
      ServerTryCancel(&srv_ctx);
    }

    // The RPC has been cancelled at this point for sure (i.e irrespective of
    // the value of `server_try_cancel` is). So, from this point forward, we
    // know that cq results are supposed to return false on server.

    // Server sends the final message and cancelled status (but the RPC is
    // already cancelled at this point. So we expect the operation to fail)
    srv_stream.Finish(send_response, Status::CANCELLED, tag(9));
    Verifier(GetParam()).Expect(9, false).Verify(cq_.get());

    // Client will see the cancellation
    cli_stream->Finish(&recv_status, tag(10));
    // TODO(sreek): The expectation here should be true. This is a bug (github
    // issue #4972)
    Verifier(GetParam()).Expect(10, false).Verify(cq_.get());
    EXPECT_FALSE(recv_status.ok());
    EXPECT_EQ(::grpc::StatusCode::CANCELLED, recv_status.error_code());
  }

  // Helper for testing server-streaming RPCs which are cancelled on the server.
  // Depending on the value of server_try_cancel parameter, this will test one
  // of the following three scenarios:
  //   CANCEL_BEFORE_PROCESSING: Rpc is cancelled by the server before sending
  //   any messages to the client
  //
  //   CANCEL_DURING_PROCESSING: Rpc is cancelled by the server while sending
  //   messages to the client
  //
  //   CANCEL_AFTER PROCESSING: Rpc is cancelled by server after sending all
  //   messages to the client (but before sending any status back to the
  //   client)
  void TestServerStreamingServerCancel(
      ServerTryCancelRequestPhase server_try_cancel) {
    ResetStub();

    EchoRequest send_request;
    EchoRequest recv_request;
    EchoResponse send_response;
    EchoResponse recv_response;
    Status recv_status;
    ClientContext cli_ctx;
    ServerContext srv_ctx;
    ServerAsyncWriter<EchoResponse> srv_stream(&srv_ctx);

    send_request.set_message("Ping");
    // Initiate the 'ResponseStream' call on the client
    std::unique_ptr<ClientAsyncReader<EchoResponse>> cli_stream(
        stub_->AsyncResponseStream(&cli_ctx, send_request, cq_.get(), tag(1)));
    Verifier(GetParam()).Expect(1, true).Verify(cq_.get());
    // On the server, request to be notified of 'ResponseStream' calls and
    // receive the call just made by the client
    service_.RequestResponseStream(&srv_ctx, &recv_request, &srv_stream,
                                   cq_.get(), cq_.get(), tag(2));
    Verifier(GetParam()).Expect(2, true).Verify(cq_.get());
    EXPECT_EQ(send_request.message(), recv_request.message());

    bool expected_cq_result = true;
    bool ignore_cq_result = false;

    if (server_try_cancel == CANCEL_BEFORE_PROCESSING) {
      ServerTryCancel(&srv_ctx);

      // We know for sure that all cq results will be false from this point
      // since the server cancelled the RPC
      expected_cq_result = false;
    }

    std::thread* server_try_cancel_thd = NULL;
    if (server_try_cancel == CANCEL_DURING_PROCESSING) {
      server_try_cancel_thd = new std::thread(
          &AsyncEnd2endServerTryCancelTest::ServerTryCancel, this, &srv_ctx);

      // Server will cancel the RPC in a parallel thread while writing responses
      // to the client. Since the cancellation can happen at anytime, some of
      // the cq results (i.e those until cancellation) might be true but it is
      // non deterministic. So better to ignore the cq results
      ignore_cq_result = true;
    }

    // Server sends three messages (tags 3, 4 and 5)
    for (int tag_idx = 3; tag_idx <= 5; tag_idx++) {
      send_response.set_message("Pong " + std::to_string(tag_idx));
      srv_stream.Write(send_response, tag(tag_idx));
      Verifier(GetParam())
          .Expect(tag_idx, expected_cq_result)
          .Verify(cq_.get(), ignore_cq_result);
    }

    if (server_try_cancel_thd != NULL) {
      server_try_cancel_thd->join();
      delete server_try_cancel_thd;
    }

    if (server_try_cancel == CANCEL_AFTER_PROCESSING) {
      ServerTryCancel(&srv_ctx);
    }

    // Client attemts to read the three messages from the server
    for (int tag_idx = 6; tag_idx <= 8; tag_idx++) {
      cli_stream->Read(&recv_response, tag(tag_idx));
      Verifier(GetParam())
          .Expect(tag_idx, expected_cq_result)
          .Verify(cq_.get(), ignore_cq_result);
    }

    // The RPC has been cancelled at this point for sure (i.e irrespective of
    // the value of `server_try_cancel` is). So, from this point forward, we
    // know that cq results are supposed to return false on server.

    // Server finishes the stream (but the RPC is already cancelled)
    srv_stream.Finish(Status::CANCELLED, tag(9));
    Verifier(GetParam()).Expect(9, false).Verify(cq_.get());

    // Client will see the cancellation
    cli_stream->Finish(&recv_status, tag(10));
    Verifier(GetParam()).Expect(10, true).Verify(cq_.get());
    EXPECT_FALSE(recv_status.ok());
    EXPECT_EQ(::grpc::StatusCode::CANCELLED, recv_status.error_code());
  }

  // Helper for testing bidirectinal-streaming RPCs which are cancelled on the
  // server.
  //
  // Depending on the value of server_try_cancel parameter, this will
  // test one of the following three scenarios:
  //   CANCEL_BEFORE_PROCESSING: Rpc is cancelled by the server before reading/
  //   writing any messages from/to the client
  //
  //   CANCEL_DURING_PROCESSING: Rpc is cancelled by the server while reading
  //   messages from the client
  //
  //   CANCEL_AFTER PROCESSING: Rpc is cancelled by server after reading all
  //   messages from the client (but before sending any status back to the
  //   client)
  void TestBidiStreamingServerCancel(
      ServerTryCancelRequestPhase server_try_cancel) {
    ResetStub();

    EchoRequest send_request;
    EchoRequest recv_request;
    EchoResponse send_response;
    EchoResponse recv_response;
    Status recv_status;
    ClientContext cli_ctx;
    ServerContext srv_ctx;
    ServerAsyncReaderWriter<EchoResponse, EchoRequest> srv_stream(&srv_ctx);

    // Initiate the call from the client side
    std::unique_ptr<ClientAsyncReaderWriter<EchoRequest, EchoResponse>>
        cli_stream(stub_->AsyncBidiStream(&cli_ctx, cq_.get(), tag(1)));
    Verifier(GetParam()).Expect(1, true).Verify(cq_.get());

    // On the server, request to be notified of the 'BidiStream' call and
    // receive the call just made by the client
    service_.RequestBidiStream(&srv_ctx, &srv_stream, cq_.get(), cq_.get(),
                               tag(2));
    Verifier(GetParam()).Expect(2, true).Verify(cq_.get());

    // Client sends the first and the only message
    send_request.set_message("Ping");
    cli_stream->Write(send_request, tag(3));
    Verifier(GetParam()).Expect(3, true).Verify(cq_.get());

    bool expected_cq_result = true;
    bool ignore_cq_result = false;

    if (server_try_cancel == CANCEL_BEFORE_PROCESSING) {
      ServerTryCancel(&srv_ctx);

      // We know for sure that all cq results will be false from this point
      // since the server cancelled the RPC
      expected_cq_result = false;
    }

    std::thread* server_try_cancel_thd = NULL;
    if (server_try_cancel == CANCEL_DURING_PROCESSING) {
      server_try_cancel_thd = new std::thread(
          &AsyncEnd2endServerTryCancelTest::ServerTryCancel, this, &srv_ctx);

      // Since server is going to cancel the RPC in a parallel thread, some of
      // the cq results (i.e those until the cancellation) might be true. Since
      // that number is non-deterministic, it is better to ignore the cq results
      ignore_cq_result = true;
    }

    srv_stream.Read(&recv_request, tag(4));
    Verifier(GetParam())
        .Expect(4, expected_cq_result)
        .Verify(cq_.get(), ignore_cq_result);

    send_response.set_message("Pong");
    srv_stream.Write(send_response, tag(5));
    Verifier(GetParam())
        .Expect(5, expected_cq_result)
        .Verify(cq_.get(), ignore_cq_result);

    cli_stream->Read(&recv_response, tag(6));
    Verifier(GetParam())
        .Expect(6, expected_cq_result)
        .Verify(cq_.get(), ignore_cq_result);

    // This is expected to succeed in all cases
    cli_stream->WritesDone(tag(7));
    Verifier(GetParam()).Expect(7, true).Verify(cq_.get());

    // This is expected to fail in all cases i.e for all values of
    // server_try_cancel. This is becasue at this point, either there are no
    // more msgs from the client (because client called WritesDone) or the RPC
    // is cancelled on the server
    srv_stream.Read(&recv_request, tag(8));
    Verifier(GetParam()).Expect(8, false).Verify(cq_.get());

    if (server_try_cancel_thd != NULL) {
      server_try_cancel_thd->join();
      delete server_try_cancel_thd;
    }

    if (server_try_cancel == CANCEL_AFTER_PROCESSING) {
      ServerTryCancel(&srv_ctx);
    }

    // The RPC has been cancelled at this point for sure (i.e irrespective of
    // the value of `server_try_cancel` is). So, from this point forward, we
    // know that cq results are supposed to return false on server.

    srv_stream.Finish(Status::CANCELLED, tag(9));
    Verifier(GetParam()).Expect(9, false).Verify(cq_.get());

    cli_stream->Finish(&recv_status, tag(10));
    Verifier(GetParam()).Expect(10, true).Verify(cq_.get());
    EXPECT_FALSE(recv_status.ok());
    EXPECT_EQ(grpc::StatusCode::CANCELLED, recv_status.error_code());
  }
};

TEST_P(AsyncEnd2endServerTryCancelTest, ClientStreamingServerTryCancelBefore) {
  TestClientStreamingServerCancel(CANCEL_BEFORE_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ClientStreamingServerTryCancelDuring) {
  TestClientStreamingServerCancel(CANCEL_DURING_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ClientStreamingServerTryCancelAfter) {
  TestClientStreamingServerCancel(CANCEL_AFTER_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerStreamingServerTryCancelBefore) {
  TestServerStreamingServerCancel(CANCEL_BEFORE_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerStreamingServerTryCancelDuring) {
  TestServerStreamingServerCancel(CANCEL_DURING_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerStreamingServerTryCancelAfter) {
  TestServerStreamingServerCancel(CANCEL_AFTER_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerBidiStreamingTryCancelBefore) {
  TestBidiStreamingServerCancel(CANCEL_BEFORE_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerBidiStreamingTryCancelDuring) {
  TestBidiStreamingServerCancel(CANCEL_DURING_PROCESSING);
}

TEST_P(AsyncEnd2endServerTryCancelTest, ServerBidiStreamingTryCancelAfter) {
  TestBidiStreamingServerCancel(CANCEL_AFTER_PROCESSING);
}

INSTANTIATE_TEST_CASE_P(AsyncEnd2end, AsyncEnd2endTest,
                        ::testing::Values(false, true));
INSTANTIATE_TEST_CASE_P(AsyncEnd2endServerTryCancel,
                        AsyncEnd2endServerTryCancelTest,
                        ::testing::Values(false));

}  // namespace
}  // namespace testing
}  // namespace grpc

int main(int argc, char** argv) {
  grpc_test_init(argc, argv);
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}