Package org.eclipse.jgit.dircache

Class DirCacheIterator

java.lang.Object

org.eclipse.jgit.treewalk.AbstractTreeIterator

org.eclipse.jgit.dircache.DirCacheIterator

Direct Known Subclasses:

DirCacheBuildIterator

public class DirCacheIterator
extends AbstractTreeIterator

Iterate a DirCache as part of a TreeWalk.

This is an iterator to adapt a loaded DirCache instance (such as read from an existing .git/index file) to the tree structure used by a TreeWalk, making it possible for applications to walk over any combination of tree objects already in the object database, index files, or working directories.

See Also:

TreeWalk

Field Summary

Fields

Modifier and Type	Field	Description
protected DirCache	cache	The cache this iterator was created to walk.
protected DirCacheEntry	currentEntry	The current file entry from cache.
protected DirCacheTree	currentSubtree	The subtree containing currentEntry if this is first entry.
protected int	ptr	Index of entry within cache.

Fields inherited from class org.eclipse.jgit.treewalk.AbstractTreeIterator

attributesNode, DEFAULT_PATH_SIZE, mode, parent, path, pathLen, pathOffset, zeroid

Constructor Summary

Constructors

Constructor	Description
DirCacheIterator(DirCache dc)	Create a new iterator for an already loaded DirCache instance.

Method Summary

Modifier and Type	Method	Description
void	back(int delta)	Move to prior entry, populating this iterator with the entry data.
EmptyTreeIterator	createEmptyTreeIterator()	Create a new iterator as though the current entry were a subtree.
AbstractTreeIterator	createSubtreeIterator(ObjectReader reader)	Create a new iterator for the current entry's subtree.
boolean	eof()	Is this tree iterator at its EOF point (no more entries)?
boolean	first()	Is this tree iterator positioned on its first entry?
DirCacheEntry	getDirCacheEntry()	Get the DirCacheEntry for the current file.
AttributesNode	getEntryAttributesNode(ObjectReader reader)	Retrieves the AttributesNode for the current entry.
boolean	hasId()	Whether the entry has a valid ObjectId.
byte[]	idBuffer()	Get the byte array buffer object IDs must be copied out of.
int	idOffset()	Get the position within AbstractTreeIterator.idBuffer() of this entry's ObjectId.
void	next(int delta)	Move to next entry, populating this iterator with the entry data.
void	reset()	Position this iterator on the first entry.

Methods inherited from class org.eclipse.jgit.treewalk.AbstractTreeIterator

createSubtreeIterator, ensurePathCapacity, findFile, findFile, getEntryFileMode, getEntryObjectId, getEntryObjectId, getEntryPathBuffer, getEntryPathHashCode, getEntryPathLength, getEntryPathString, getEntryRawMode, getName, getNameLength, getNameOffset, growPath, idEqual, isWorkTree, needsStopWalk, pathCompare, pathCompare, skip, stopWalk, toString

Methods inherited from class java.lang.Object

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

Field Detail

cache

protected final DirCache cache

The cache this iterator was created to walk.

ptr

protected int ptr

Index of entry within cache.

currentEntry

protected DirCacheEntry currentEntry

The current file entry from cache.

currentSubtree

protected DirCacheTree currentSubtree

The subtree containing currentEntry if this is first entry.

Constructor Detail

DirCacheIterator

public DirCacheIterator(DirCache dc)

Create a new iterator for an already loaded DirCache instance.

The iterator implementation may copy part of the cache's data during construction, so the cache must be read in prior to creating the iterator.

Parameters:

dc - the cache to walk. It must be already loaded into memory.

Method Detail

createSubtreeIterator

public AbstractTreeIterator createSubtreeIterator(ObjectReader reader)
                                           throws IncorrectObjectTypeException,
                                                  IOException

Create a new iterator for the current entry's subtree.

The parent reference of the iterator must be this, otherwise the caller would not be able to exit out of the subtree iterator correctly and return to continue walking this.

Specified by:

createSubtreeIterator in class AbstractTreeIterator

Parameters:

reader - reader to load the tree data from.

Returns:

a new parser that walks over the current subtree.

Throws:

IncorrectObjectTypeException - the current entry is not actually a tree and cannot be parsed as though it were a tree.

IOException - a loose object or pack file could not be read.

createEmptyTreeIterator

public EmptyTreeIterator createEmptyTreeIterator()

Create a new iterator as though the current entry were a subtree.

Overrides:

createEmptyTreeIterator in class AbstractTreeIterator

Returns:

a new empty tree iterator.

hasId

public boolean hasId()

Whether the entry has a valid ObjectId.

Specified by:

hasId in class AbstractTreeIterator

Returns:

true if the entry has a valid ObjectId.

idBuffer

public byte[] idBuffer()

Get the byte array buffer object IDs must be copied out of.

The id buffer contains the bytes necessary to construct an ObjectId for the current entry of this iterator. The buffer can be the same buffer for all entries, or it can be a unique buffer per-entry. Implementations are encouraged to expose their private buffer whenever possible to reduce garbage generation and copying costs.

Specified by:

idBuffer in class AbstractTreeIterator

Returns:

byte array the implementation stores object IDs within.

See Also:

AbstractTreeIterator.getEntryObjectId()

idOffset

public int idOffset()

Get the position within AbstractTreeIterator.idBuffer() of this entry's ObjectId.

Specified by:

idOffset in class AbstractTreeIterator

Returns:

offset into the array returned by AbstractTreeIterator.idBuffer() where the ObjectId must be copied out of.

reset

public void reset()

Position this iterator on the first entry. The default implementation of this method uses back(1) until first() is true. This is most likely not the most efficient method of repositioning the iterator to its first entry, so subclasses are strongly encouraged to override the method.

Overrides:

reset in class AbstractTreeIterator

first

public boolean first()

Is this tree iterator positioned on its first entry?

An iterator is positioned on the first entry if back(1) would be an invalid request as there is no entry before the current one.

An empty iterator (one with no entries) will be first() && eof().

Specified by:

first in class AbstractTreeIterator

Returns:

true if the iterator is positioned on the first entry.

eof

public boolean eof()

Is this tree iterator at its EOF point (no more entries)?

An iterator is at EOF if there is no current entry.

Specified by:

eof in class AbstractTreeIterator

Returns:

true if we have walked all entries and have none left.

next

public void next(int delta)

Move to next entry, populating this iterator with the entry data.

The delta indicates how many moves forward should occur. The most common delta is 1 to move to the next entry.

Implementations must populate the following members:

• AbstractTreeIterator.mode
• AbstractTreeIterator.path (from AbstractTreeIterator.pathOffset to AbstractTreeIterator.pathLen)
• AbstractTreeIterator.pathLen

as well as any implementation dependent information necessary to accurately return data from AbstractTreeIterator.idBuffer() and AbstractTreeIterator.idOffset() when demanded.

Specified by:

next in class AbstractTreeIterator

Parameters:

delta - number of entries to move the iterator by. Must be a positive, non-zero integer.

back

public void back(int delta)

Move to prior entry, populating this iterator with the entry data.

The delta indicates how many moves backward should occur.The most common delta is 1 to move to the prior entry.

Implementations must populate the following members:

• AbstractTreeIterator.mode
• AbstractTreeIterator.path (from AbstractTreeIterator.pathOffset to AbstractTreeIterator.pathLen)
• AbstractTreeIterator.pathLen

as well as any implementation dependent information necessary to accurately return data from AbstractTreeIterator.idBuffer() and AbstractTreeIterator.idOffset() when demanded.

Specified by:

back in class AbstractTreeIterator

Parameters:

delta - number of entries to move the iterator by. Must be a positive, non-zero integer.

getDirCacheEntry

public DirCacheEntry getDirCacheEntry()

Get the DirCacheEntry for the current file.

Returns:

the current cache entry, if this iterator is positioned on a non-tree.

getEntryAttributesNode

public AttributesNode getEntryAttributesNode(ObjectReader reader)
                                      throws IOException

Retrieves the AttributesNode for the current entry.

Parameters:

reader - ObjectReader used to parse the .gitattributes entry.

Returns:

AttributesNode for the current entry.

Throws:

IOException

Since:

3.7