org.eclipse.jgit.internal.storage.reftable

Class ReftableReader

java.lang.Object

org.eclipse.jgit.internal.storage.reftable.Reftable

org.eclipse.jgit.internal.storage.reftable.ReftableReader

All Implemented Interfaces:

AutoCloseable

public class ReftableReader
extends Reftable
implements AutoCloseable

Reads a reftable formatted file.

ReftableReader is not thread-safe. Concurrent readers need their own instance to read from the same file.

Field Summary

Fields inherited from class org.eclipse.jgit.internal.storage.reftable.Reftable

includeDeletes

Constructor Summary

Constructors

Constructor and Description
ReftableReader(BlockSource src) Initialize a new reftable reader.

Method Summary

Modifier and Type	Method and Description
LogCursor	allLogs() Seek reader to read log records.
RefCursor	allRefs() Seek to the first reference, to iterate in order.
int	blockSize() Get the block size in bytes chosen for this file by the writer.
RefCursor	byObjectId(AnyObjectId id) Match references pointing to a specific object.
void	close()
boolean	hasObjectMap()
long	maxUpdateIndex() Get the maximum update index for ref entries that appear in this reftable.
long	minUpdateIndex() Get the minimum update index for ref entries that appear in this reftable.
LogCursor	seekLog(String refName, long updateIndex) Seek to an update index in a reference's log.
RefCursor	seekRef(String refName) Seek to a reference.
RefCursor	seekRefsWithPrefix(String prefix) Seek references with prefix.
long	size() Get size of the reftable, in bytes.

Methods inherited from class org.eclipse.jgit.internal.storage.reftable.Reftable

exactRef, from, hasId, hasRef, hasRefsWithPrefix, resolve, seekLog, setIncludeDeletes

Methods inherited from class java.lang.Object

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

Constructor Detail

ReftableReader

public ReftableReader(BlockSource src)

Initialize a new reftable reader.

Parameters:

src - the file content to read.

Method Detail

blockSize

public int blockSize()
              throws IOException

Get the block size in bytes chosen for this file by the writer.

Returns:

the block size in bytes chosen for this file by the writer. Most reads from the BlockSource will be aligned to the block size.

Throws:

IOException - file cannot be read.

hasObjectMap

public boolean hasObjectMap()
                     throws IOException

Specified by:

hasObjectMap in class Reftable

Returns:

whether this reftable can do a fast SHA1 => ref lookup.

Throws:

IOException - on I/O problems.

minUpdateIndex

public long minUpdateIndex()
                    throws IOException

Get the minimum update index for ref entries that appear in this reftable.

Specified by:

minUpdateIndex in class Reftable

Returns:

the minimum update index for ref entries that appear in this reftable.

Throws:

IOException - file cannot be read.

maxUpdateIndex

public long maxUpdateIndex()
                    throws IOException

Get the maximum update index for ref entries that appear in this reftable.

Specified by:

maxUpdateIndex in class Reftable

Returns:

the maximum update index for ref entries that appear in this reftable.

Throws:

IOException - file cannot be read.

allRefs

public RefCursor allRefs()
                  throws IOException

Seek to the first reference, to iterate in order.

Specified by:

allRefs in class Reftable

Returns:

cursor to iterate.

Throws:

IOException - if references cannot be read.

seekRef

public RefCursor seekRef(String refName)
                  throws IOException

Seek to a reference.

This method will seek to the reference refName. If present, the returned cursor will iterate exactly one entry. If not found, an empty cursor is returned.

Specified by:

seekRef in class Reftable

Parameters:

refName - reference name.

Returns:

cursor to iterate; empty cursor if no references match.

Throws:

IOException - if references cannot be read.

seekRefsWithPrefix

public RefCursor seekRefsWithPrefix(String prefix)
                             throws IOException

Seek references with prefix.

The method will seek all the references starting with prefix as a prefix. If no references start with this prefix, an empty cursor is returned.

Specified by:

seekRefsWithPrefix in class Reftable

Parameters:

prefix - prefix to find.

Returns:

cursor to iterate; empty cursor if no references match.

Throws:

IOException - if references cannot be read.

byObjectId

public RefCursor byObjectId(AnyObjectId id)
                     throws IOException

Match references pointing to a specific object.

Specified by:

byObjectId in class Reftable

Parameters:

id - object to find.

Returns:

cursor to iterate; empty cursor if no references match.

Throws:

IOException - if references cannot be read.

allLogs

public LogCursor allLogs()
                  throws IOException

Seek reader to read log records.

Specified by:

allLogs in class Reftable

Returns:

cursor to iterate; empty cursor if no logs are present.

Throws:

IOException - if logs cannot be read.

seekLog

public LogCursor seekLog(String refName,
                         long updateIndex)
                  throws IOException

Seek to an update index in a reference's log.

Specified by:

seekLog in class Reftable

Parameters:

refName - exact name of the reference whose log to read.

updateIndex - most recent index to return first in the log cursor. Log records at or before updateIndex will be returned.

Returns:

cursor to iterate; empty cursor if no logs match.

Throws:

IOException - if logs cannot be read.

size

public long size()
          throws IOException

Get size of the reftable, in bytes.

Returns:

size of the reftable, in bytes.

Throws:

IOException - size cannot be obtained.

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Throws:

IOException