org.eclipse.jgit.dircache
Class DirCacheIterator

java.lang.Object
  extended by org.eclipse.jgit.treewalk.AbstractTreeIterator
      extended by 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
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
DEFAULT_PATH_SIZE, mode, path, pathLen, pathOffset, zeroid
 
Constructor Summary
DirCacheIterator(DirCache dc)
          Create a new iterator for an already loaded DirCache instance.
 
Method Summary
 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.
 boolean hasId()
           
 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, getEntryFileMode, getEntryObjectId, getEntryObjectId, getEntryPathBuffer, getEntryPathHashCode, getEntryPathLength, getEntryPathString, getEntryRawMode, getName, getNameLength, getNameOffset, growPath, idEqual, 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
Description copied from class: AbstractTreeIterator
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()
Description copied from class: AbstractTreeIterator
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()
Specified by:
hasId in class AbstractTreeIterator
Returns:
true if the entry has a valid ObjectId.

idBuffer

public byte[] idBuffer()
Description copied from class: AbstractTreeIterator
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()
Description copied from class: AbstractTreeIterator
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()
Description copied from class: AbstractTreeIterator
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()
Description copied from class: AbstractTreeIterator
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()
Description copied from class: AbstractTreeIterator
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)
Description copied from class: AbstractTreeIterator
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:

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)
Description copied from class: AbstractTreeIterator
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:

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.


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