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//
//
// 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 <atomic>
#include <cstring>
#include <memory>
#include <util/generic/string.h>
#include <util/string/cast.h>
#include <utility>
#include <vector>
#include <grpc/grpc.h>
#include <grpc/impl/connectivity_state.h>
#include <grpc/slice.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/time.h>
#include <grpcpp/channel.h>
#include <grpcpp/client_context.h>
#include <grpcpp/completion_queue.h>
#include <grpcpp/impl/call.h>
#include <grpcpp/impl/call_op_set_interface.h>
#include <grpcpp/impl/completion_queue_tag.h>
#include <grpcpp/impl/rpc_method.h>
#include <grpcpp/impl/sync.h>
#include <grpcpp/support/client_interceptor.h>
#include <grpcpp/support/slice.h>
#include "src/core/lib/iomgr/iomgr.h"
namespace grpc {
Channel::Channel(
const TString& host, grpc_channel* channel,
std::vector<
std::unique_ptr<grpc::experimental::ClientInterceptorFactoryInterface>>
interceptor_creators)
: host_(host), c_channel_(channel) {
interceptor_creators_ = std::move(interceptor_creators);
}
Channel::~Channel() {
grpc_channel_destroy(c_channel_);
CompletionQueue* callback_cq = callback_cq_.load(std::memory_order_relaxed);
if (callback_cq != nullptr) {
if (grpc_iomgr_run_in_background()) {
// gRPC-core provides the backing needed for the preferred CQ type
callback_cq->Shutdown();
} else {
CompletionQueue::ReleaseCallbackAlternativeCQ(callback_cq);
}
}
}
namespace {
inline grpc_slice SliceFromArray(const char* arr, size_t len) {
return grpc_slice_from_copied_buffer(arr, len);
}
TString GetChannelInfoField(grpc_channel* channel,
grpc_channel_info* channel_info,
char*** channel_info_field) {
char* value = nullptr;
memset(channel_info, 0, sizeof(*channel_info));
*channel_info_field = &value;
grpc_channel_get_info(channel, channel_info);
if (value == nullptr) return "";
TString result = value;
gpr_free(value);
return result;
}
} // namespace
TString Channel::GetLoadBalancingPolicyName() const {
grpc_channel_info channel_info;
return GetChannelInfoField(c_channel_, &channel_info,
&channel_info.lb_policy_name);
}
TString Channel::GetServiceConfigJSON() const {
grpc_channel_info channel_info;
return GetChannelInfoField(c_channel_, &channel_info,
&channel_info.service_config_json);
}
namespace experimental {
void ChannelResetConnectionBackoff(Channel* channel) {
grpc_channel_reset_connect_backoff(channel->c_channel_);
}
} // namespace experimental
grpc::internal::Call Channel::CreateCallInternal(
const grpc::internal::RpcMethod& method, grpc::ClientContext* context,
grpc::CompletionQueue* cq, size_t interceptor_pos) {
const bool kRegistered = method.channel_tag() && context->authority().empty();
grpc_call* c_call = nullptr;
if (kRegistered) {
c_call = grpc_channel_create_registered_call(
c_channel_, context->propagate_from_call_,
context->propagation_options_.c_bitmask(), cq->cq(),
method.channel_tag(), context->raw_deadline(), nullptr);
} else {
const ::TString* host_str = nullptr;
if (!context->authority_.empty()) {
host_str = &context->authority_;
} else if (!host_.empty()) {
host_str = &host_;
}
grpc_slice method_slice =
SliceFromArray(method.name(), strlen(method.name()));
grpc_slice host_slice;
if (host_str != nullptr) {
host_slice = grpc::SliceFromCopiedString(*host_str);
}
c_call = grpc_channel_create_call(
c_channel_, context->propagate_from_call_,
context->propagation_options_.c_bitmask(), cq->cq(), method_slice,
host_str == nullptr ? nullptr : &host_slice, context->raw_deadline(),
nullptr);
grpc_slice_unref(method_slice);
if (host_str != nullptr) {
grpc_slice_unref(host_slice);
}
}
grpc_census_call_set_context(c_call, context->census_context());
// ClientRpcInfo should be set before call because set_call also checks
// whether the call has been cancelled, and if the call was cancelled, we
// should notify the interceptors too.
auto* info = context->set_client_rpc_info(
method.name(), method.suffix_for_stats(), method.method_type(), this,
interceptor_creators_, interceptor_pos);
context->set_call(c_call, shared_from_this());
return grpc::internal::Call(c_call, this, cq, info);
}
grpc::internal::Call Channel::CreateCall(
const grpc::internal::RpcMethod& method, grpc::ClientContext* context,
CompletionQueue* cq) {
return CreateCallInternal(method, context, cq, 0);
}
void Channel::PerformOpsOnCall(grpc::internal::CallOpSetInterface* ops,
grpc::internal::Call* call) {
ops->FillOps(
call); // Make a copy of call. It's fine since Call just has pointers
}
void* Channel::RegisterMethod(const char* method) {
return grpc_channel_register_call(
c_channel_, method, host_.empty() ? nullptr : host_.c_str(), nullptr);
}
grpc_connectivity_state Channel::GetState(bool try_to_connect) {
return grpc_channel_check_connectivity_state(c_channel_, try_to_connect);
}
namespace {
class TagSaver final : public grpc::internal::CompletionQueueTag {
public:
explicit TagSaver(void* tag) : tag_(tag) {}
~TagSaver() override {}
bool FinalizeResult(void** tag, bool* /*status*/) override {
*tag = tag_;
delete this;
return true;
}
private:
void* tag_;
};
} // namespace
void Channel::NotifyOnStateChangeImpl(grpc_connectivity_state last_observed,
gpr_timespec deadline,
grpc::CompletionQueue* cq, void* tag) {
TagSaver* tag_saver = new TagSaver(tag);
grpc_channel_watch_connectivity_state(c_channel_, last_observed, deadline,
cq->cq(), tag_saver);
}
bool Channel::WaitForStateChangeImpl(grpc_connectivity_state last_observed,
gpr_timespec deadline) {
grpc::CompletionQueue cq;
bool ok = false;
void* tag = nullptr;
NotifyOnStateChangeImpl(last_observed, deadline, &cq, nullptr);
cq.Next(&tag, &ok);
GPR_ASSERT(tag == nullptr);
return ok;
}
namespace {
class ShutdownCallback : public grpc_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(grpc::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_completion_queue_functor* cb, int) {
auto* callback = static_cast<ShutdownCallback*>(cb);
delete callback->cq_;
delete callback;
}
private:
grpc::CompletionQueue* cq_ = nullptr;
};
} // namespace
::grpc::CompletionQueue* Channel::CallbackCQ() {
// TODO(vjpai): Consider using a single global CQ for the default CQ
// if there is no explicit per-channel CQ registered
CompletionQueue* callback_cq = callback_cq_.load(std::memory_order_acquire);
if (callback_cq != nullptr) {
return callback_cq;
}
// The callback_cq_ wasn't already set, so grab a lock and set it up exactly
// once for this channel.
grpc::internal::MutexLock l(&mu_);
callback_cq = callback_cq_.load(std::memory_order_relaxed);
if (callback_cq == nullptr) {
if (grpc_iomgr_run_in_background()) {
// gRPC-core provides the backing needed for the preferred CQ type
auto* shutdown_callback = new 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);
} else {
// Otherwise we need to use the alternative CQ variant
callback_cq = CompletionQueue::CallbackAlternativeCQ();
}
callback_cq_.store(callback_cq, std::memory_order_release);
}
return callback_cq;
}
} // namespace grpc
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