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

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

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/*
 * Copyright 2011 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.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonParser;

/**
 * Detect and parse the provided source map.
 * @author johnlenz@google.com (John Lenz)
 */
public final class SourceMapConsumerFactory {
    private static final JsonParser PARSER = new JsonParser();

    /** not constructible */
    private SourceMapConsumerFactory() {
    }

    /**
     * @param contents The string representing the source map file contents.
     * @return The parsed source map.
     * @throws SourceMapParseException
     */
    public static SourceMapping parse(String contents) throws SourceMapParseException {
        return parse(contents, null);
    }

    /**
     * @param contents The string representing the source map file contents.
     * @param supplier A supplier for any referenced maps.
     * @return The parsed source map.
     * @throws SourceMapParseException
     */
    public static SourceMapping parse(String contents, SourceMapSupplier supplier) throws SourceMapParseException {
        // Version 1, starts with a magic string
        if (contents.startsWith("/** Begin line maps. **/")) {
            throw new SourceMapParseException("This appears to be a V1 SourceMap, which is not supported.");
        } else if (contents.startsWith("{")) {
            try {
                // Revision 2 and 3, are JSON Objects
                JsonElement jsonElement = PARSER.parse(contents);
                if (!jsonElement.isJsonObject()) {
                    throw new SourceMapParseException("Expected a JSON Object.");
                }
                JsonObject sourceMapRoot = jsonElement.getAsJsonObject();

                // Check basic assertions about the format.
                int version = sourceMapRoot.get("version").getAsInt();
                switch (version) {
                case 3: {
                    SourceMapConsumerV3 consumer = new SourceMapConsumerV3();
                    consumer.parse(sourceMapRoot, supplier);
                    return consumer;
                }
                default:
                    throw new SourceMapParseException("Unknown source map version:" + version);
                }
            } catch (JsonParseException ex) {
                throw new SourceMapParseException("JSON parse exception: " + ex);
            }
        }

        throw new SourceMapParseException("unable to detect source map format");
    }
}