Class NameConflictTreeWalk
- All Implemented Interfaces:
AutoCloseable
,AttributesProvider
Due to the way a Git tree is organized the standard
TreeWalk
won't easily find a D/F conflict
when merging two or more trees together. In the standard TreeWalk the file
will be returned first, and then much later the directory will be returned.
This makes it impossible for the application to efficiently detect and handle
the conflict.
Using this walk implementation causes the directory to report earlier than usual, at the same time as the non-directory entry. This permits the application to handle the D/F conflict in a single step. The directory is returned only once, so it does not get returned later in the iteration.
When a D/F conflict is detected
TreeWalk.isSubtree()
will return true and
TreeWalk.enterSubtree()
will recurse into
the subtree, no matter which iterator originally supplied the subtree.
Because conflicted directories report early, using this walk implementation
to populate a DirCacheBuilder
may cause the
automatic resorting to run and fix the entry ordering.
This walk implementation requires more CPU to implement a look-ahead and a look-behind to merge a D/F pair together, or to skip a previously reported directory. In typical Git repositories the look-ahead cost is 0 and the look-behind doesn't trigger, as users tend not to create trees which contain both "foo" as a directory and "foo.c" as a file.
In the worst-case however several thousand look-ahead steps per walk step may be necessary, making the overhead quite significant. Since this worst-case should never happen this walk implementation has made the time/space tradeoff in favor of more-time/less-space, as that better suits the typical case.
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Nested Class Summary
Nested classes/interfaces inherited from class org.eclipse.jgit.treewalk.TreeWalk
TreeWalk.OperationType
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate AbstractTreeIterator
private boolean
private static final int
Fields inherited from class org.eclipse.jgit.treewalk.TreeWalk
currentHead, depth, trees
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Constructor Summary
ConstructorsConstructorDescriptionCreate a new tree walker for a given repository.Create a new tree walker for a given repository.NameConflictTreeWalk
(Repository repo, ObjectReader or) Create a new tree walker for a given repository. -
Method Summary
Modifier and TypeMethodDescriptionprivate AbstractTreeIterator
combineDF
(AbstractTreeIterator minRef) private AbstractTreeIterator
fastMin()
boolean
True if the current entry is covered by a directory/file conflict.private boolean
private static boolean
(package private) AbstractTreeIterator
min()
private static boolean
private boolean
(package private) void
(package private) void
private boolean
skipEntry
(AbstractTreeIterator minRef) (package private) void
stopWalk()
Notify iterators the walk is aborting.Methods inherited from class org.eclipse.jgit.treewalk.TreeWalk
addTree, addTree, close, enterSubtree, exitSubtree, forPath, forPath, forPath, forPath, getAttributes, getAttributes, getAttributesNodeProvider, getCheckoutEolStreamType, getDepth, getEolStreamType, getFileMode, getFileMode, getFilter, getFilterCommand, getNameString, getObjectId, getObjectId, getObjectReader, getOperationType, getPathLength, getPathString, getRawMode, getRawPath, getSmudgeCommand, getSmudgeCommand, getTree, getTree, getTreeCount, idEqual, isPathMatch, isPathPrefix, isPathSuffix, isPostChildren, isPostOrderTraversal, isRecursive, isSubtree, next, pathOf, pathOf, reset, reset, reset, setAttributesNodeProvider, setFilter, setHead, setOperationType, setPostOrderTraversal, setRecursive
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Field Details
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TREE_MODE
private static final int TREE_MODE -
fastMinHasMatch
private boolean fastMinHasMatch -
dfConflict
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Constructor Details
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NameConflictTreeWalk
Create a new tree walker for a given repository.- Parameters:
repo
- the repository the walker will obtain data from.
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NameConflictTreeWalk
Create a new tree walker for a given repository.- Parameters:
repo
- the repository the walker will obtain data from.or
- the reader the walker will obtain tree data from.- Since:
- 4.3
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NameConflictTreeWalk
Create a new tree walker for a given repository.- Parameters:
or
- the reader the walker will obtain tree data from.
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Method Details
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min
- Overrides:
min
in classTreeWalk
- Throws:
CorruptObjectException
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fastMin
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nameEqual
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isGitlink
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isTree
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skipEntry
- Throws:
CorruptObjectException
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combineDF
- Throws:
CorruptObjectException
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popEntriesEqual
- Overrides:
popEntriesEqual
in classTreeWalk
- Throws:
CorruptObjectException
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skipEntriesEqual
- Overrides:
skipEntriesEqual
in classTreeWalk
- Throws:
CorruptObjectException
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stopWalk
Description copied from class:TreeWalk
Notify iterators the walk is aborting.Primarily to notify
DirCacheBuildIterator
the walk is aborting so that it can copy any remaining entries.- Overrides:
stopWalk
in classTreeWalk
- Throws:
IOException
- if traversal of remaining entries throws an exception during object access. This should never occur as remaining trees should already be in memory, however the methods used to finish traversal are declared to throw IOException.
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needsStopWalk
private boolean needsStopWalk() -
isDirectoryFileConflict
public boolean isDirectoryFileConflict()True if the current entry is covered by a directory/file conflict. This means that for some prefix of the current entry's path, this walk has detected a directory/file conflict. Also true if the current entry itself is a directory/file conflict. Example: If this TreeWalk points to foo/bar/a.txt and this method returns true then you know that either for path foo or for path foo/bar files and folders were detected.- Returns:
true
if the current entry is covered by a directory/file conflict,false
otherwise
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