| // Licensed to the Apache Software Foundation (ASF) under one |
| // or more contributor license agreements. See the NOTICE file |
| // distributed with this work for additional information |
| // regarding copyright ownership. The ASF licenses this file |
| // to you 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. |
| #pragma once |
| |
| #include <exception> |
| #include <string> |
| #include <vector> |
| |
| #include <glog/logging.h> |
| // IWYU pragma: no_include <yaml-cpp/node/detail/iterator.h> |
| // IWYU pragma: no_include <yaml-cpp/node/detail/iterator_fwd.h> |
| // IWYU pragma: no_include <yaml-cpp/node/impl.h> |
| // IWYU pragma: no_include <yaml-cpp/node/iterator.h> |
| // IWYU pragma: no_include <yaml-cpp/node/node.h> |
| // IWYU pragma: no_include <yaml-cpp/node/type.h> |
| #include <yaml-cpp/yaml.h> // IWYU pragma: keep |
| |
| #include "kudu/gutil/macros.h" |
| #include "kudu/gutil/port.h" |
| #include "kudu/gutil/strings/substitute.h" |
| #include "kudu/util/status.h" |
| |
| namespace kudu { |
| |
| // Wraps the YAML parsing functionality of YAML::Node. |
| // |
| // This class can read yaml content from a file, extract scalar, map and array type of values. |
| class YamlReader { |
| public: |
| explicit YamlReader(std::string filename); |
| ~YamlReader() = default; |
| |
| Status Init(); |
| |
| // Extractor methods. |
| // |
| // Look for a field with the name of 'field' in the given node. |
| // Return Status::OK if it can be found and extracted as the specified type, |
| // or return Status::NotFound if it cannot be found, or Status::Corruption if |
| // the node is not extractable or the field can not be extracted as the type. |
| |
| template <typename T> |
| static Status ExtractScalar(const YAML::Node* node, |
| const std::string& field, |
| T* result); |
| |
| static Status ExtractMap(const YAML::Node* node, |
| const std::string& field, |
| YAML::Node* result); |
| |
| template <typename T> |
| static Status ExtractArray(const YAML::Node* node, |
| const std::string& field, |
| std::vector<T>* result); |
| |
| const YAML::Node* node() const { return &node_; } |
| |
| private: |
| static const char* TypeToString(YAML::NodeType::value t); |
| |
| static Status ExtractField(const YAML::Node* node, |
| const std::string& field, |
| YAML::Node* result); |
| |
| std::string filename_; |
| YAML::Node node_; |
| |
| DISALLOW_COPY_AND_ASSIGN(YamlReader); |
| }; |
| |
| template <typename T> |
| Status YamlReader::ExtractScalar(const YAML::Node* node, |
| const std::string& field, |
| T* result) { |
| CHECK(result); |
| YAML::Node val; |
| RETURN_NOT_OK(ExtractField(node, field, &val)); |
| if (PREDICT_FALSE(!val.IsScalar())) { |
| return Status::Corruption(strings::Substitute( |
| "wrong type during field extraction: expected scalar but got $0", |
| TypeToString(val.Type()))); |
| } |
| *result = val.as<T>(); |
| return Status::OK(); |
| } |
| |
| template <typename T> |
| Status YamlReader::ExtractArray(const YAML::Node* node, |
| const std::string& field, |
| std::vector<T>* result) { |
| CHECK(result); |
| YAML::Node val; |
| RETURN_NOT_OK(ExtractField(node, field, &val)); |
| if (PREDICT_FALSE(!val.IsSequence())) { |
| return Status::Corruption(strings::Substitute( |
| "wrong type during field extraction: expected sequence but got $0", |
| TypeToString(val.Type()))); |
| } |
| result->reserve(val.size()); |
| for (YAML::const_iterator iter = val.begin(); iter != val.end(); ++iter) { |
| try { |
| if (PREDICT_FALSE(!iter->IsScalar())) { |
| return Status::Corruption(strings::Substitute( |
| "wrong type during field extraction: expected scalar but got $0", |
| TypeToString(iter->Type()))); |
| } |
| result->push_back(iter->as<T>()); |
| } catch (std::exception& e) { |
| return Status::Corruption(strings::Substitute("parse list element error: $0", e.what())); |
| } |
| } |
| return Status::OK(); |
| } |
| |
| } // namespace kudu |