src/core/lib/resolver/server_address.cc

/*
 *
 * Copyright 2018 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/support/port_platform.h>

#include "src/core/lib/resolver/server_address.h"

#include <memory>
#include <string>
#include <vector>

#include "absl/strings/str_cat.h"
#include "absl/strings/str_format.h"
#include "absl/strings/str_join.h"

#include "src/core/lib/address_utils/sockaddr_utils.h"

namespace grpc_core {

//
// ServerAddressWeightAttribute
//
const char* ServerAddressWeightAttribute::kServerAddressWeightAttributeKey =
    "server_address_weight";

//
// ServerAddress
//

ServerAddress::ServerAddress(
    const grpc_resolved_address& address, grpc_channel_args* args,
    std::map<const char*, std::unique_ptr<AttributeInterface>> attributes)
    : address_(address), args_(args), attributes_(std::move(attributes)) {}

ServerAddress::ServerAddress(
    const void* address, size_t address_len, grpc_channel_args* args,
    std::map<const char*, std::unique_ptr<AttributeInterface>> attributes)
    : args_(args), attributes_(std::move(attributes)) {
  memcpy(address_.addr, address, address_len);
  address_.len = static_cast<socklen_t>(address_len);
}

ServerAddress::ServerAddress(const ServerAddress& other)
    : address_(other.address_), args_(grpc_channel_args_copy(other.args_)) {
  for (const auto& p : other.attributes_) {
    attributes_[p.first] = p.second->Copy();
  }
}
ServerAddress& ServerAddress::operator=(const ServerAddress& other) {
  if (&other == this) {
    return *this;
  }
  address_ = other.address_;
  grpc_channel_args_destroy(args_);
  args_ = grpc_channel_args_copy(other.args_);
  attributes_.clear();
  for (const auto& p : other.attributes_) {
    attributes_[p.first] = p.second->Copy();
  }
  return *this;
}

ServerAddress::ServerAddress(ServerAddress&& other) noexcept
    : address_(other.address_),
      args_(other.args_),
      attributes_(std::move(other.attributes_)) {
  other.args_ = nullptr;
}

ServerAddress& ServerAddress::operator=(ServerAddress&& other) noexcept {
  address_ = other.address_;
  grpc_channel_args_destroy(args_);
  args_ = other.args_;
  other.args_ = nullptr;
  attributes_ = std::move(other.attributes_);
  return *this;
}

namespace {

int CompareAttributes(
    const std::map<const char*,
                   std::unique_ptr<ServerAddress::AttributeInterface>>&
        attributes1,
    const std::map<const char*,
                   std::unique_ptr<ServerAddress::AttributeInterface>>&
        attributes2) {
  auto it2 = attributes2.begin();
  for (auto it1 = attributes1.begin(); it1 != attributes1.end(); ++it1) {
    // attributes2 has fewer elements than attributes1
    if (it2 == attributes2.end()) return -1;
    // compare keys
    int retval = strcmp(it1->first, it2->first);
    if (retval != 0) return retval;
    // compare values
    retval = it1->second->Cmp(it2->second.get());
    if (retval != 0) return retval;
    ++it2;
  }
  // attributes1 has fewer elements than attributes2
  if (it2 != attributes2.end()) return 1;
  // equal
  return 0;
}

}  // namespace

int ServerAddress::Cmp(const ServerAddress& other) const {
  if (address_.len > other.address_.len) return 1;
  if (address_.len < other.address_.len) return -1;
  int retval = memcmp(address_.addr, other.address_.addr, address_.len);
  if (retval != 0) return retval;
  retval = grpc_channel_args_compare(args_, other.args_);
  if (retval != 0) return retval;
  return CompareAttributes(attributes_, other.attributes_);
}

const ServerAddress::AttributeInterface* ServerAddress::GetAttribute(
    const char* key) const {
  auto it = attributes_.find(key);
  if (it == attributes_.end()) return nullptr;
  return it->second.get();
}

// Returns a copy of the address with a modified attribute.
// If the new value is null, the attribute is removed.
ServerAddress ServerAddress::WithAttribute(
    const char* key, std::unique_ptr<AttributeInterface> value) const {
  ServerAddress address = *this;
  if (value == nullptr) {
    address.attributes_.erase(key);
  } else {
    address.attributes_[key] = std::move(value);
  }
  return address;
}

std::string ServerAddress::ToString() const {
  auto addr_str = grpc_sockaddr_to_string(&address_, false);
  std::vector<std::string> parts = {
      addr_str.ok() ? addr_str.value() : addr_str.status().ToString(),
  };
  if (args_ != nullptr) {
    parts.emplace_back(absl::StrCat("args=", grpc_channel_args_string(args_)));
  }
  if (!attributes_.empty()) {
    std::vector<std::string> attrs;
    for (const auto& p : attributes_) {
      attrs.emplace_back(absl::StrCat(p.first, "=", p.second->ToString()));
    }
    parts.emplace_back(
        absl::StrCat("attributes={", absl::StrJoin(attrs, ", "), "}"));
  }
  return absl::StrJoin(parts, " ");
}

std::string ServerAddressWeightAttribute::ToString() const {
  return absl::StrFormat("%d", weight_);
}

}  // namespace grpc_core