org.eclipse.jgit.internal.storage.reftable

Class MergedReftable

java.lang.Object

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

org.eclipse.jgit.internal.storage.reftable.MergedReftable

All Implemented Interfaces:

java.lang.AutoCloseable

public class MergedReftable
extends Reftable

Merges multiple reference tables together.

A MergedReftable merge-joins multiple ReftableReader on the fly. Tables higher/later in the stack shadow lower/earlier tables, hiding references that been updated/replaced.

By default deleted references are skipped and not returned to the caller. Reftable.setIncludeDeletes(boolean) can be used to modify this behavior if the caller needs to preserve deletions during partial compaction.

A MergedReftable is not thread-safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	MergedReftable.LogQueueEntry
private class	MergedReftable.MergedLogCursor
private class	MergedReftable.MergedRefCursor
private static class	MergedReftable.RefQueueEntry

Field Summary

Fields

Modifier and Type	Field and Description
private Reftable[]	tables

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

includeDeletes

Constructor Summary

Constructors

Constructor and Description
MergedReftable(java.util.List<Reftable> tableStack) Initialize a merged table 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.
RefCursor	byObjectId(AnyObjectId name) Match references pointing to a specific object.
void	close()
(package private) int	queueSize()
LogCursor	seekLog(java.lang.String refName, long updateIdx) Seek to an update index in a reference's log.
RefCursor	seekRef(java.lang.String name) Seek either to a reference, or a reference subtree.

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

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

Methods inherited from class java.lang.Object

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

Field Detail

tables

private final Reftable[] tables

Constructor Detail

MergedReftable

public MergedReftable(java.util.List<Reftable> tableStack)

Initialize a merged table reader.

The tables in tableStack will be closed when this MergedReftable is closed.

Parameters:

tableStack - stack of tables to read from. The base of the stack is at index 0, the most recent should be at the top of the stack at tableStack.size() - 1. The top of the stack (higher index) shadows the base of the stack (lower index).

Method Detail

allRefs

public RefCursor allRefs()
                  throws java.io.IOException

Seek to the first reference, to iterate in order.

Specified by:

allRefs in class Reftable

Returns:

cursor to iterate.

Throws:

java.io.IOException - if references cannot be read.

seekRef

public RefCursor seekRef(java.lang.String name)
                  throws java.io.IOException

Seek either to a reference, or a reference subtree.

If refName ends with "/" the method will seek to the subtree of all references starting with refName as a prefix. If no references start with this prefix, an empty cursor is returned.

Otherwise exactly refName will be looked for. 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:

name - reference name or subtree to find.

Returns:

cursor to iterate; empty cursor if no references match.

Throws:

java.io.IOException - if references cannot be read.

byObjectId

public RefCursor byObjectId(AnyObjectId name)
                     throws java.io.IOException

Match references pointing to a specific object.

Specified by:

byObjectId in class Reftable

Parameters:

name - object to find.

Returns:

cursor to iterate; empty cursor if no references match.

Throws:

java.io.IOException - if references cannot be read.

allLogs

public LogCursor allLogs()
                  throws java.io.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:

java.io.IOException - if logs cannot be read.

seekLog

public LogCursor seekLog(java.lang.String refName,
                         long updateIdx)
                  throws java.io.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.

updateIdx - 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:

java.io.IOException - if logs cannot be read.

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in class Reftable

Throws:

java.io.IOException

queueSize

int queueSize()