StringHelper.java

/**
 * This file is part of git-as-svn. It is subject to the license terms
 * in the LICENSE file found in the top-level directory of this distribution
 * and at http://www.gnu.org/licenses/gpl-2.0.html. No part of git-as-svn,
 * including this file, may be copied, modified, propagated, or distributed
 * except according to the terms contained in the LICENSE file.
 */
package svnserver;

import org.jetbrains.annotations.Contract;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

/**
 * Useful string utilites.
 *
 * @author Artem V. Navrotskiy <bozaro@users.noreply.github.com>
 */
public final class StringHelper {
  @NotNull
  private static final char[] DIGITS = "0123456789abcdef".toCharArray();
  @NotNull
  private static final TimeZone UTC = TimeZone.getTimeZone("UTC");

  @SuppressWarnings("MagicNumber")
  public static String toHex(byte[] data) {
    final StringBuilder result = new StringBuilder();
    for (byte i : data) {
      result.append(DIGITS[(i >> 4) & 0x0F]);
      result.append(DIGITS[i & 0x0F]);
    }
    return result.toString();
  }

  @NotNull
  public static String formatDate(long time) {
    final SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
    df.setTimeZone(UTC);
    return df.format(new Date(time));
  }

  @NotNull
  public static String joinPath(@NotNull String path, @Nullable String localPath) {
    if (localPath == null || localPath.isEmpty()) {
      return normalize(path);
    }
    if (localPath.startsWith("/")) {
      return normalize(localPath);
    }
    return normalize(path + (path.endsWith("/") ? "" : "/") + localPath);
  }

  @NotNull
  public static String normalize(@NotNull String path) {
    if (path.isEmpty()) return "";
    String result = path;
    if (result.charAt(0) != '/') {
      result = "/" + result;
    } else if (result.length() == 1) {
      return "";
    }
    return result.endsWith("/") ? result.substring(0, result.length() - 1) : result;
  }

  @NotNull
  public static String normalizeDir(@NotNull String path) {
    if (path.isEmpty()) return "/";
    String result = path;
    if (result.charAt(0) != '/') {
      result = "/" + result;
    } else if (result.length() == 1) {
      return "/";
    }
    return result.endsWith("/") ? result : (result + "/");
  }

  @NotNull
  public static String parentDir(@NotNull String fullPath) {
    int index = fullPath.lastIndexOf('/');
    return index >= 0 ? fullPath.substring(0, index) : "";
  }

  @NotNull
  public static String baseName(@NotNull String fullPath) {
    return fullPath.substring(fullPath.lastIndexOf('/') + 1);
  }

  /**
   * Returns true, if parentPath is base path of childPath.
   *
   * @param parentPath Parent path.
   * @param childPath  Child path.
   * @return Returns true, if parentPath is base path of childPath.
   */
  public static boolean isParentPath(@NotNull String parentPath, @NotNull String childPath) {
    if (childPath.startsWith(parentPath)) {
      int parentLength = parentPath.length();
      if (childPath.length() == parentLength)
        return true;
      if (childPath.charAt(parentLength) == '/')
        return true;
      if ((parentLength > 0) && (childPath.charAt(parentLength - 1) == '/'))
        return true;
    }
    return false;
  }

  /**
   * Get childPath from parentPath or null.
   *
   * @param parentPath    Parent path.
   * @param fullChildPath Full child path.
   * @return Returns child path related parent path or null.
   */
  @Nullable
  public static String getChildPath(@NotNull String parentPath, @NotNull String fullChildPath) {
    if (parentPath.isEmpty()) {
      if ((fullChildPath.length() > 1) && (fullChildPath.charAt(1) == '/')) {
        return fullChildPath.substring(1);
      }
      return fullChildPath;
    }
    if (fullChildPath.startsWith(parentPath)) {
      int parentLength = parentPath.length();
      if (fullChildPath.length() == parentLength)
        return "";
      if (fullChildPath.charAt(parentLength) == '/')
        return fullChildPath.substring(parentLength + 1);
      if ((parentLength > 0) && (fullChildPath.charAt(parentLength - 1) == '/'))
        return fullChildPath.substring(parentLength);
    }
    return null;
  }

  @Contract("null -> null; !null -> !null")
  public static String getFirstLine(@Nullable String message) {
    if (message == null)
      return null;
    int eol = message.indexOf('\n');
    return (eol >= 0) ? message.substring(0, eol) : message;
  }
}