SourceMapConsumerFactory.java

/*
 * 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.github.sommeri.sourcemap;

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 class SourceMapConsumerFactory {

  /** 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 {
    //SMS: (source map separation):  Version 1 support removed because it requires google guava
    //    if (contents.startsWith("/** Begin line maps. **/")) {
    //      
    //      SourceMapConsumerV1 consumer =  new SourceMapConsumerV1();
    //      consumer.parse(contents);
    //      return consumer;
    //    } else 
    if (contents.startsWith("{")) {
      try {
        // Revision 2 and 3, are JSON Objects
        JsonObject sourceMapRoot = new JsonParser().parse(contents).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");
  }
}