Method readFile

src/tsd/GraphHandler.java:596–628

Reads a file into a byte array. @param query The query being handled (for logging purposes). @param file The file to read. @param max_length The maximum number of bytes to read from the file. @return null if the file doesn't exist or is empty or couldn't be read, otherwise a byte array of up

(final HttpQuery query,
                                 final File file,
                                 final int max_length)

   * read, otherwise a byte array of up to {@code max_length} bytes.
   */
  private static byte[] readFile(final HttpQuery query,
                                 final File file,
                                 final int max_length) {
    final int length = (int) file.length();
    if (length <= 0) {
      return null;
    }
    FileInputStream in;
    try {
      in = new FileInputStream(file.getPath());
    } catch (FileNotFoundException e) {
      return null;
    }
    try {
      final byte[] buf = new byte[Math.min(length, max_length)];
      final int read = in.read(buf);
      if (read != buf.length) {
        logError(query, "When reading " + file + ": read only "
                 + read + " bytes instead of " + buf.length);
        return null;
      }
      return buf;
    } catch (IOException e) {
      logError(query, "Error while reading " + file, e);
      return null;
    } finally {
      try {
        in.close();
      } catch (IOException e) {
        logError(query, "Error while closing " + file, e);
      }
    }
  }

  /**
   * Attempts to read the cached {@code .json} file for this query.