com.google.api.codegen.configgen.ConfigYamlReader.java Source code

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Here is the source code for com.google.api.codegen.configgen.ConfigYamlReader.java

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/* Copyright 2017 Google LLC
 *
 * 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
 *
 *      https://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.
 */
package com.google.api.codegen.configgen;

import com.google.api.codegen.ConfigProto;
import com.google.api.codegen.configgen.nodes.ConfigNode;
import com.google.api.codegen.configgen.nodes.FieldConfigNode;
import com.google.common.base.Charsets;
import com.google.common.base.Splitter;
import com.google.common.io.Files;
import java.io.File;
import java.io.IOException;
import java.io.StringReader;
import java.util.List;
import org.yaml.snakeyaml.Yaml;
import org.yaml.snakeyaml.composer.ComposerException;
import org.yaml.snakeyaml.nodes.MappingNode;
import org.yaml.snakeyaml.nodes.Node;

/** Reads YAML into a FieldConfigNode. */
public class ConfigYamlReader {
    public FieldConfigNode generateConfigNode(File file, ConfigHelper helper) {
        int initialErrorCount = helper.getErrorCount();
        String input;
        try {
            input = Files.toString(file, Charsets.UTF_8);
        } catch (IOException e) {
            helper.error("Cannot read configuration file: %s", e.getMessage());
            return null;
        }

        if (input.trim().isEmpty()) {
            helper.error("Empty YAML document");
            return null;
        }

        Node tree;
        try {
            tree = new Yaml().compose(new StringReader(input));
        } catch (ComposerException e) {
            helper.error(e.getProblemMark(), "Parsing error: %s", e.getMessage());
            return null;
        } catch (Exception e) {
            helper.error("Parsing error: %s", e.getMessage());
            return null;
        }

        if (tree == null) {
            helper.error("Parsing error");
            return null;
        }

        if (!(tree instanceof MappingNode)) {
            helper.error(tree, "Expected a map as a root object.");
            return null;
        }

        List<String> lines = Splitter.on(System.lineSeparator()).splitToList(input);
        ConfigNode configNode = new ConfigYamlNodeReader(lines, helper).readMessageNode((MappingNode) tree,
                ConfigProto.getDescriptor());
        return helper.getErrorCount() == initialErrorCount ? new FieldConfigNode(0, "").setChild(configNode) : null;
    }
}