1 // 2 // Copyright (C) 2023 The Android Open Source Project 3 // 4 // Licensed under the Apache License, Version 2.0 (the "License"); 5 // you may not use this file except in compliance with the License. 6 // You may obtain a copy of the License at 7 // 8 // http://www.apache.org/licenses/LICENSE-2.0 9 // 10 // Unless required by applicable law or agreed to in writing, software 11 // distributed under the License is distributed on an "AS IS" BASIS, 12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 // See the License for the specific language governing permissions and 14 // limitations under the License. 15 16 #include <type_traits> 17 #include <vector> 18 19 #include <fmt/core.h> 20 #include <google/protobuf/message.h> 21 #include <google/protobuf/text_format.h> 22 #include <google/protobuf/util/json_util.h> 23 24 /* Format proto messages as textproto with {} or {:t} and json with {:j}. */ 25 template <typename T> 26 struct fmt::formatter< 27 T, 28 std::enable_if_t<std::is_base_of_v<google::protobuf::Message, T>, char>> { 29 public: 30 constexpr format_parse_context::iterator parse(format_parse_context& ctx) { 31 auto it = ctx.begin(); 32 for (; it != ctx.end() && *it != '}'; it++) { 33 format_ = *it; 34 } 35 return it; 36 } 37 format_context::iterator format(const T& proto, format_context& ctx) const { 38 std::string text; 39 if (format_ == 't') { 40 if (!google::protobuf::TextFormat::PrintToString(proto, &text)) { 41 return fmt::format_to(ctx.out(), "(proto format error"); 42 } 43 } else if (format_ == 'j') { 44 auto result = google::protobuf::util::MessageToJsonString(proto, &text); 45 if (!result.ok()) { 46 return fmt::format_to(ctx.out(), "(json error: {})", 47 std::string(result.ToString())); 48 } 49 } else { 50 return fmt::format_to(ctx.out(), "(unknown format specifier)"); 51 } 52 return fmt::format_to(ctx.out(), "{}", text); 53 } 54 55 private: 56 char format_ = 't'; 57 }; 58