io.milton.zsync

Class UploadMaker

java.lang.Object

io.milton.zsync.UploadMaker

public class UploadMaker
extends Object

An object that performs the client-side operations needed to generate ZSync PUT data.

In order to update a file on a server, the client first needs to download the appropriate .zsync containing the metadata of the server file. The client should then instantiate an UploadMaker, passing to the constructor this .zsync file as well as the local file to be uploaded. On construction, the UploadMaker will determine the data ranges and assembly instructions that need to be sent to the server, and will automatically fill in an internal Upload object. The client can then invoke the getInputStream method, which will return a stream which should be used as the body of a PUT request.

E.g:

< code> UploadMaker um = new UploadMaker(File clientFile, File zsFile);
InputStream putData = um.getInputStream();

Note: This is one of two classes that can be used to create a ZSync upload. The other class, UploadMakerEx, performs the same functions but may perform better for certain rare cases.

Author:

Nick

See Also:

Upload}, {@link UploadReader}, {@link UploadMakerEx}

Field Summary

Fields

Modifier and Type	Field and Description
File	localCopy The local file that will replace the server file
File	serversMetafile The .zsync of the server file to be replaced

Constructor Summary

Constructors

Constructor and Description
UploadMaker(File sourceFile, File destMeta) Constructor that automatically creates and fills in an internal upload object.

Method Summary

Modifier and Type	Method and Description
static List<DataRange>	getDataRanges(List<Range> ranges, File local) Returns the List of DataRange objects containing the portions of the client file to be uploaded to the server.
static InputStream	getDataStream(List<Range> ranges, File local) Generates the dataStream portion of an Upload from the local file and a List of Ranges
InputStream	getInputStream() Returns the stream of bytes to be used as the body of a ZSync PUT.
static InputStream	getRelocStream(List<RelocateRange> relocList) Generates the relocStream portion of an Upload from a List of RelocateRanges.
void	init()
InputStream	makeUpload()
static InputStream	serversMissingRanges(long[] fileMap, File local, int blockSize) Determines the byte ranges of new data that need to be sent to the server to update its file.
static InputStream	serversRelocationRanges(long[] fileMap, int blockSize, long fileLength, boolean combineRanges) Returns the assembly instructions needed by the server to relocate the blocks it already has.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

localCopy

public final File localCopy

The local file that will replace the server file

serversMetafile

public final File serversMetafile

The .zsync of the server file to be replaced

Constructor Detail

UploadMaker

public UploadMaker(File sourceFile,
                   File destMeta)
            throws IOException

Constructor that automatically creates and fills in an internal upload object.

Parameters:

sourceFile - The local file to be uploaded

destMeta - The zsync of the server's file

Throws:

IOException

Method Detail

makeUpload

public InputStream makeUpload()
                       throws IOException

Throws:

IOException

init

public void init()
          throws IOException

Throws:

IOException

serversMissingRanges

public static InputStream serversMissingRanges(long[] fileMap,
                                               File local,
                                               int blockSize)
                                        throws IOException

Determines the byte ranges of new data that need to be sent to the server to update its file.

The fileMap argument should be an array that maps matching blocks from the server's file (the side that sent the metadata) to those in the client file, such that fileMap[seq] == off means that block number seq in the server's file matches the block in the local file beginning at byte off. An invalid offset is ignored and should be used to indicate that the local file contains no match for that block. The fileMap array can be obtained from the MakeContext class.

Parameters:

fileMap - An array mapping blocks in server file to their offsets in local file

fileLength - The length of the local file to be uploaded

blockSize - The size of a block. Must correspond to block size used in fileMap

Returns:

The List of byte Ranges that need to be sent

Throws:

IOException

serversRelocationRanges

public static InputStream serversRelocationRanges(long[] fileMap,
                                                  int blockSize,
                                                  long fileLength,
                                                  boolean combineRanges)
                                           throws IOException

Returns the assembly instructions needed by the server to relocate the blocks it already has.

The combineRanges argument determines whether contiguous matching blocks should be combined into a single range, e.g. given a blockSize of 100, whether 0-10/500, 10-20/600, 20-30/700 should be combined into the single RelocateRange of 0-30/500.

Parameters:

fileMap - An array mapping blocks in the server file to their matches in the local file

blockSize - The block size used by fileMap

fileLength - The length of the local file to be uploaded

combineRanges - Whether consecutive matches should be combined into a single RelocateRange

Returns:

A list of RelocateRange instructions to be sent to the server

Throws:

IOException

getDataRanges

public static List<DataRange> getDataRanges(List<Range> ranges,
                                            File local)
                                     throws IOException

Returns the List of DataRange objects containing the portions of the client file to be uploaded to the server. Currently unused.

Parameters:

ranges - The List of Ranges from the client file needed by the server, which can be obtained from #serversMissingRanges(long[], long, int)

local - The client file to be uploaded

Returns:

The List of DataRange objects containing client file portions to be uploaded

Throws:

IOException

getInputStream

public InputStream getInputStream()
                           throws UnsupportedEncodingException,
                                  IOException

Returns the stream of bytes to be used as the body of a ZSync PUT.

Note: Any temporary files used to store the data for the stream will be deleted once the stream is closed, so a second invocation of this method may not work.

Returns:

The InputStream containing the data for a ZSync PUT

Throws:

UnsupportedEncodingException

IOException

getRelocStream

public static InputStream getRelocStream(List<RelocateRange> relocList)
                                  throws IOException

Generates the relocStream portion of an Upload from a List of RelocateRanges.

Parameters:

relocList - The List of RelocateRanges

Returns:

An InputStream containing the relocStream portion of an Upload

Throws:

IOException

getDataStream

public static InputStream getDataStream(List<Range> ranges,
                                        File local)
                                 throws IOException

Generates the dataStream portion of an Upload from the local file and a List of Ranges

Parameters:

ranges - The List of byte ranges

local - The local file being uploaded

Returns:

The InputStream containing the dataStream portion of an Upload

Throws:

IOException