Ejemplo n.º 1
0
        /// <summary> Read a particular segmentFileName.  Note that this may
        /// throw an IOException if a commit is in process.
        ///
        /// </summary>
        /// <param name="directory">-- directory containing the segments file
        /// </param>
        /// <param name="segmentFileName">-- segment file to load
        /// </param>
        /// <throws>  CorruptIndexException if the index is corrupt </throws>
        /// <throws>  IOException if there is a low-level IO error </throws>
        public void  Read(Directory directory, System.String segmentFileName)
        {
            bool success = false;

            // Clear any previous segments:
            Clear();

            var input = new ChecksumIndexInput(directory.OpenInput(segmentFileName));

            generation = GenerationFromSegmentsFileName(segmentFileName);

            lastGeneration = generation;

            try
            {
                int format = input.ReadInt();
                if (format < 0)
                {
                    // file contains explicit format info
                    // check that it is a format we can understand
                    if (format < CURRENT_FORMAT)
                    {
                        throw new CorruptIndexException("Unknown format version: " + format);
                    }
                    version = input.ReadLong();                    // read version
                    counter = input.ReadInt();                     // read counter
                }
                else
                {
                    // file is in old format without explicit format info
                    counter = format;
                }

                for (int i = input.ReadInt(); i > 0; i--)
                {
                    // read segmentInfos
                    Add(new SegmentInfo(directory, format, input));
                }

                if (format >= 0)
                {
                    // in old format the version number may be at the end of the file
                    if (input.FilePointer >= input.Length())
                    {
                        version = (DateTime.UtcNow.Ticks / TimeSpan.TicksPerMillisecond);
                    }
                    // old file format without version number
                    else
                    {
                        version = input.ReadLong();                         // read version
                    }
                }

                if (format <= FORMAT_USER_DATA)
                {
                    if (format <= FORMAT_DIAGNOSTICS)
                    {
                        userData = input.ReadStringStringMap();
                    }
                    else if (0 != input.ReadByte())
                    {
                        // TODO: Should be read-only map
                        userData = new HashMap <string, string> {
                            { "userData", input.ReadString() }
                        };
                    }
                    else
                    {
                        // TODO: Should be empty read-only map
                        userData = new HashMap <string, string>();
                    }
                }
                else
                {
                    // TODO: Should be empty read-only map
                    userData = new HashMap <string, string>();
                }

                if (format <= FORMAT_CHECKSUM)
                {
                    long checksumNow  = input.Checksum;
                    long checksumThen = input.ReadLong();
                    if (checksumNow != checksumThen)
                    {
                        throw new CorruptIndexException("checksum mismatch in segments file");
                    }
                }
                success = true;
            }
            finally
            {
                input.Close();
                if (!success)
                {
                    // Clear any segment infos we had loaded so we
                    // have a clean slate on retry:
                    Clear();
                }
            }
        }