plugins/svn4idea/src/org/jetbrains/idea/svn/properties/ExternalsDefinitionParser.java

/*
 * Copyright 2000-2014 JetBrains s.r.o.
 *
 * 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 org.jetbrains.idea.svn.properties;

import com.intellij.openapi.util.text.StringUtil;
import com.intellij.util.containers.ContainerUtil;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.idea.svn.commandLine.SvnBindException;

import java.util.HashMap;
import java.util.Map;

/**
 * @author Konstantin Kolosovsky.
 */
public class ExternalsDefinitionParser {

  /**
   * Parses "svn:externals" property in format starting from svn 1.5.
   *
   * @return map of externals definitions: key - relative directory, value - corresponding complete externals definition.
   */
  @NotNull
  public static Map<String, String> parseExternalsProperty(@NotNull String externals) throws SvnBindException {
    HashMap<String, String> map = ContainerUtil.newHashMap();

    for (String external : StringUtil.splitByLines(externals, true)) {
      map.put(parseRelativeDirectory(external), external);
    }

    return map;
  }

  /**
   * Parses relative directory from externals definition (in format starting from svn 1.5). Restrictions for relative directory:
   * - is at the end of externals definition separated from other parameters by ' ' char
   * - could be quoted with '"' char
   * - certain chars could be escaped with '\' char
   */
  @NotNull
  public static String parseRelativeDirectory(@NotNull String s) throws SvnBindException {
    s = s.trim();

    int length = s.length();
    String result;

    if (isUnescapedQuote(s, length - 1)) {
      int index = lastUnescapedIndexOf(s, length - 1, '"');
      assertIndex(s, index, "Could not find start quote");
      result = s.substring(index + 1, length - 1);
    }
    else {
      int index = lastUnescapedIndexOf(s, length, ' ');
      assertIndex(s, index, "Could not find separating space");
      result = s.substring(index + 1);
    }

    return unescape(result);
  }

  private static void assertIndex(@NotNull String s, int index, @NotNull String message) throws SvnBindException {
    if (index < 0) {
      throw new SvnBindException(message + " - " + s);
    }
  }

  @NotNull
  private static String unescape(@NotNull String s) {
    return s.replace("\\", "");
  }

  /**
   * "from" index is excluded.
   */
  private static int lastUnescapedIndexOf(@NotNull String s, int from, char c) {
    int result = from;

    do {
      result = s.lastIndexOf(c, result - 1);
    }
    while (result != -1 && !isUnescaped(s, result, c));

    return result;
  }

  private static boolean isUnescapedQuote(@NotNull String s, int index) {
    return isUnescaped(s, index, '"');
  }

  private static boolean isUnescaped(@NotNull String s, int index, char c) {
    return StringUtil.isChar(s, index, c) && !StringUtil.isChar(s, index - 1, '\\');
  }
}