com.google.debugging.sourcemap.SourceMapObjectParser.java Source code

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Here is the source code for com.google.debugging.sourcemap.SourceMapObjectParser.java

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/*
 * Copyright 2016 The Closure Compiler 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.
 */
package com.google.debugging.sourcemap;

import com.google.common.collect.ImmutableList;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;

/**
 * Java implementation of the source map parser.
 */
public class SourceMapObjectParser {
    public static SourceMapObject parse(String contents) throws SourceMapParseException {

        SourceMapObject.Builder builder = SourceMapObject.builder();

        try {
            JsonObject sourceMapRoot = new Gson().fromJson(contents, JsonObject.class);

            builder.setVersion(sourceMapRoot.get("version").getAsInt());
            builder.setFile(getStringOrNull(sourceMapRoot, "file"));
            builder.setLineCount(sourceMapRoot.has("lineCount") ? sourceMapRoot.get("lineCount").getAsInt() : -1);
            builder.setMappings(getStringOrNull(sourceMapRoot, "mappings"));
            builder.setSourceRoot(getStringOrNull(sourceMapRoot, "sourceRoot"));

            if (sourceMapRoot.has("sections")) {
                ImmutableList.Builder<SourceMapSection> listBuilder = ImmutableList.builder();
                for (JsonElement each : sourceMapRoot.get("sections").getAsJsonArray()) {
                    listBuilder.add(buildSection(each.getAsJsonObject()));
                }
                builder.setSections(listBuilder.build());
            }

            builder.setSources(getJavaStringArray(sourceMapRoot.get("sources")));
            builder.setNames(getJavaStringArray(sourceMapRoot.get("names")));

            Map<String, Object> extensions = new LinkedHashMap<>();
            for (Map.Entry<String, JsonElement> entry : sourceMapRoot.entrySet()) {
                if (entry.getKey().startsWith("x_")) {
                    extensions.put(entry.getKey(), entry.getValue());
                }
            }
            builder.setExtensions(Collections.unmodifiableMap(extensions));

        } catch (JsonParseException ex) {
            throw new SourceMapParseException("JSON parse exception: " + ex);
        }

        return builder.build();
    }

    private static SourceMapSection buildSection(JsonObject section) throws SourceMapParseException {
        JsonObject offset = section.get("offset").getAsJsonObject();
        int line = offset.get("line").getAsInt();
        int column = offset.get("column").getAsInt();

        if (section.has("map") && section.has("url")) {
            throw new SourceMapParseException("Invalid map format: section may not have both 'map' and 'url'");
        } else if (section.has("url")) {
            return SourceMapSection.forURL(section.get("url").getAsString(), line, column);
        } else if (section.has("map")) {
            return SourceMapSection.forMap(section.get("map").toString(), line, column);
        }

        throw new SourceMapParseException("Invalid map format: section must have either 'map' or 'url'");
    }

    private static String getStringOrNull(JsonObject object, String key) {
        return object.has(key) ? object.get(key).getAsString() : null;
    }

    private static String[] getJavaStringArray(JsonElement element) {
        if (element == null) {
            return null;
        }
        JsonArray array = element.getAsJsonArray();
        int len = array.size();
        String[] result = new String[len];
        for (int i = 0; i < len; i++) {
            result[i] = array.get(i).getAsString();
        }
        return result;
    }

    private SourceMapObjectParser() {
    }
}