Class BlameGenerator
- All Implemented Interfaces:
AutoCloseable
Applications that want a simple one-shot computation of blame for a file
should use computeBlameResult()
to prepare the entire result in one
method call. This may block for significant time as the history of the
repository must be traversed until information is gathered for every line.
Applications that want more incremental update behavior may use either the
raw next()
streaming approach supported by this class, or construct
a BlameResult
using
BlameResult.create(BlameGenerator)
and
incrementally construct the result with
BlameResult.computeNext()
.
This class is not thread-safe.
An instance of BlameGenerator can only be used once. To blame multiple files the application must create a new BlameGenerator.
During blame processing there are two files involved:
- result - The file whose lines are being examined. This is the revision the user is trying to view blame/annotation information alongside of.
- source - The file that was blamed with supplying one or more lines of data into result. The source may be a different file path (due to copy or rename). Source line numbers may differ from result line numbers due to lines being added/removed in intermediate revisions.
The blame algorithm is implemented by initially assigning responsibility for all lines of the result to the starting commit. A difference against the commit's ancestor is computed, and responsibility is passed to the ancestor commit for any lines that are common. The starting commit is blamed only for the lines that do not appear in the ancestor, if any. The loop repeats using the ancestor, until there are no more lines to acquire information on, or the file's creation point is discovered in history.
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Field Summary
FieldsModifier and TypeFieldDescriptionprivate DiffAlgorithm
private final MutableObjectId
private Candidate
Blame is currently assigned to this source.private Region
private Candidate
Potential candidates, sorted by commit time descending.private ObjectReader
private int
Number of lines that still need to be discovered.private RenameDetector
private final Repository
private final PathFilter
private RevWalk
Revision pool used to acquire commits from.private RevFlag
Indicates the commit was put into the queue at least once.private RawTextComparator
private TreeWalk
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Constructor Summary
ConstructorsConstructorDescriptionBlameGenerator
(Repository repository, String path) Create a blame generator for the repository and path (relative to repository) -
Method Summary
Modifier and TypeMethodDescriptionprivate boolean
blameEntireRegionOnParent
(Candidate n, RevCommit parent) void
close()
Execute the generator in a blocking fashion until all data is ready.private boolean
done()
private boolean
find
(RevCommit commit, PathFilter path) private DiffEntry
findRename
(RevCommit parent, RevCommit commit, PathFilter path) private static byte[]
getBytes
(String path, InputStream in, long maxLength) getHeads
(Repository repo, ObjectId head) int
Get number of lines in the current region being blamed togetSourceCommit()
Obtain the RenameDetector, allowing the application to configure its settings for rename score and breaking behavior.int
Get rename scoreGet repositoryGet complete file contents of the result file blame is annotatingint
Get one past the range of the result thatgetSourceCommit()
has been blamed for providingGet result pathint
Get first line of the result thatgetSourceCommit()
has been blamed for providingGet source authorGet the revision blamed for the current region.Get source committerGet complete contents of the source file blamed for the current output regionint
Get one past the range of the source data that has been blamed for the current regionGet source pathint
Get first line of the source data that has been blamed for the current regionprivate void
initRevPool
(boolean reverse) private static final boolean
isFile
(int rawMode) private static boolean
Allocate a new RevFlag for use by the caller.boolean
next()
Step the blame algorithm one iteration.private Candidate
pop()
Pushes HEAD, index, and working tree as appropriate for blaming the file given in the constructorBlameGenerator(Repository, String)
against HEAD.private boolean
private boolean
Push a candidate blob onto the generator's traversal stack.Push a candidate blob onto the generator's traversal stack.push
(String description, AnyObjectId id) Push a candidate object onto the generator's traversal stack.private void
private void
push
(Candidate.BlobCandidate toInsert) private boolean
reverse
(AnyObjectId start, Collection<? extends ObjectId> end) Configure the generator to compute reverse blame (history of deletes).reverse
(AnyObjectId start, AnyObjectId end) Configure the generator to compute reverse blame (history of deletes).private boolean
reverseResult
(Candidate parent, Candidate source) setDiffAlgorithm
(DiffAlgorithm algorithm) Difference algorithm to use when comparing revisions.setFollowFileRenames
(boolean follow) Enable (or disable) following file renames, on by default.setTextComparator
(RawTextComparator comparator) Text comparator to use when comparing revisions.private boolean
private boolean
splitBlameWithParent
(Candidate n, RevCommit parent)
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Field Details
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repository
-
resultPath
-
idBuf
-
revPool
Revision pool used to acquire commits from. -
SEEN
Indicates the commit was put into the queue at least once. -
reader
-
treeWalk
-
diffAlgorithm
-
textComparator
-
renameDetector
-
queue
Potential candidates, sorted by commit time descending. -
remaining
private int remainingNumber of lines that still need to be discovered. -
outCandidate
Blame is currently assigned to this source. -
outRegion
-
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Constructor Details
-
BlameGenerator
Create a blame generator for the repository and path (relative to repository)- Parameters:
repository
- repository to access revision data from.path
- initial path of the file to start scanning (relative to the repository).
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Method Details
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initRevPool
private void initRevPool(boolean reverse) -
getRepository
Get repository- Returns:
- repository being scanned for revision history
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getResultPath
Get result path- Returns:
- path file path being processed
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setDiffAlgorithm
Difference algorithm to use when comparing revisions.- Parameters:
algorithm
- aDiffAlgorithm
- Returns:
this
-
setTextComparator
Text comparator to use when comparing revisions.- Parameters:
comparator
- aRawTextComparator
- Returns:
this
-
setFollowFileRenames
Enable (or disable) following file renames, on by default.If true renames are followed using the standard FollowFilter behavior used by RevWalk (which matches
git log --follow
in the C implementation). This is not the same as copy/move detection as implemented by the C implementation's ofgit blame -M -C
.- Parameters:
follow
- enable following.- Returns:
this
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getRenameDetector
Obtain the RenameDetector, allowing the application to configure its settings for rename score and breaking behavior.- Returns:
- the rename detector, or
null
ifsetFollowFileRenames(false)
.
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push
Push a candidate blob onto the generator's traversal stack.Candidates should be pushed in history order from oldest-to-newest. Applications should push the starting commit first, then the index revision (if the index is interesting), and finally the working tree copy (if the working tree is interesting).
- Parameters:
description
- description of the blob revision, such as "Working Tree".contents
- contents of the file.- Returns:
this
- Throws:
IOException
- the repository cannot be read.
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push
Push a candidate blob onto the generator's traversal stack.Candidates should be pushed in history order from oldest-to-newest. Applications should push the starting commit first, then the index revision (if the index is interesting), and finally the working tree copy (if the working tree is interesting).
- Parameters:
description
- description of the blob revision, such as "Working Tree".contents
- contents of the file.- Returns:
this
- Throws:
IOException
- the repository cannot be read.
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prepareHead
Pushes HEAD, index, and working tree as appropriate for blaming the file given in the constructorBlameGenerator(Repository, String)
against HEAD. Includes special handling in case the file is in conflict state from an unresolved merge conflict.- Returns:
this
- Throws:
NoHeadException
- if the repository has no HEADIOException
- if an error occurs- Since:
- 5.6
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getHeads
private List<RevCommit> getHeads(Repository repo, ObjectId head) throws NoWorkTreeException, IOException - Throws:
NoWorkTreeException
IOException
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getBytes
- Throws:
IOException
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push
Push a candidate object onto the generator's traversal stack.Candidates should be pushed in history order from oldest-to-newest. Applications should push the starting commit first, then the index revision (if the index is interesting), and finally the working tree copy (if the working tree is interesting).
- Parameters:
description
- description of the blob revision, such as "Working Tree".id
- may be a commit or a blob.- Returns:
this
- Throws:
IOException
- the repository cannot be read.
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reverse
Configure the generator to compute reverse blame (history of deletes).This method is expensive as it immediately runs a RevWalk over the history spanning the expression
start..end
(end being more recent than start) and then performs the equivalent operation aspush(String, AnyObjectId)
to begin blame traversal from the commit named bystart
walking forwards through history untilend
blaming line deletions.A reverse blame may produce multiple sources for the same result line, each of these is a descendant commit that removed the line, typically this occurs when the same deletion appears in multiple side branches such as due to a cherry-pick. Applications relying on reverse should use
BlameResult
as it filters these duplicate sources and only remembers the first (oldest) deletion.- Parameters:
start
- oldest commit to traverse from. The result file will be loaded from this commit's tree.end
- most recent commit to stop traversal at. Usually an active branch tip, tag, or HEAD.- Returns:
this
- Throws:
IOException
- the repository cannot be read.
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reverse
public BlameGenerator reverse(AnyObjectId start, Collection<? extends ObjectId> end) throws IOException Configure the generator to compute reverse blame (history of deletes).This method is expensive as it immediately runs a RevWalk over the history spanning the expression
start..end
(end being more recent than start) and then performs the equivalent operation aspush(String, AnyObjectId)
to begin blame traversal from the commit named bystart
walking forwards through history untilend
blaming line deletions.A reverse blame may produce multiple sources for the same result line, each of these is a descendant commit that removed the line, typically this occurs when the same deletion appears in multiple side branches such as due to a cherry-pick. Applications relying on reverse should use
BlameResult
as it filters these duplicate sources and only remembers the first (oldest) deletion.- Parameters:
start
- oldest commit to traverse from. The result file will be loaded from this commit's tree.end
- most recent commits to stop traversal at. Usually an active branch tip, tag, or HEAD.- Returns:
this
- Throws:
IOException
- the repository cannot be read.
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newFlag
Allocate a new RevFlag for use by the caller.- Parameters:
name
- unique name of the flag in the blame context.- Returns:
- the newly allocated flag.
- Since:
- 3.4
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computeBlameResult
Execute the generator in a blocking fashion until all data is ready.- Returns:
- the complete result. Null if no file exists for the given path.
- Throws:
IOException
- the repository cannot be read.
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next
Step the blame algorithm one iteration.- Returns:
- true if the generator has found a region's source. The getSource*
and
getResultStart()
,getResultEnd()
methods can be used to inspect the region found. False if there are no more regions to describe. - Throws:
IOException
- repository cannot be read.
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done
private boolean done() -
result
- Throws:
IOException
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reverseResult
- Throws:
IOException
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pop
-
push
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push
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processOne
- Throws:
IOException
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blameEntireRegionOnParent
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splitBlameWithParent
- Throws:
IOException
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split
- Throws:
IOException
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processMerge
- Throws:
IOException
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getSourceCommit
Get the revision blamed for the current region.The source commit may be null if the line was blamed to an uncommitted revision, such as the working tree copy, or during a reverse blame if the line survives to the end revision (e.g. the branch tip).
- Returns:
- current revision being blamed.
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getSourceAuthor
Get source author- Returns:
- current author being blamed
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getSourceCommitter
Get source committer- Returns:
- current committer being blamed
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getSourcePath
Get source path- Returns:
- path of the file being blamed
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getRenameScore
public int getRenameScore()Get rename score- Returns:
- rename score if a rename occurred in
getSourceCommit()
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getSourceStart
public int getSourceStart()Get first line of the source data that has been blamed for the current region- Returns:
- first line of the source data that has been blamed for the
current region. This is line number of where the region was added
during
getSourceCommit()
in filegetSourcePath()
.
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getSourceEnd
public int getSourceEnd()Get one past the range of the source data that has been blamed for the current region- Returns:
- one past the range of the source data that has been blamed for
the current region. This is line number of where the region was
added during
getSourceCommit()
in filegetSourcePath()
.
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getResultStart
public int getResultStart()Get first line of the result thatgetSourceCommit()
has been blamed for providing- Returns:
- first line of the result that
getSourceCommit()
has been blamed for providing. Line numbers use 0 based indexing.
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getResultEnd
public int getResultEnd()Get one past the range of the result thatgetSourceCommit()
has been blamed for providing- Returns:
- one past the range of the result that
getSourceCommit()
has been blamed for providing. Line numbers use 0 based indexing. Because a source cannot be blamed for an empty region of the result,getResultEnd()
is always at least one larger thangetResultStart()
.
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getRegionLength
public int getRegionLength()Get number of lines in the current region being blamed togetSourceCommit()
- Returns:
- number of lines in the current region being blamed to
getSourceCommit()
. This is always the value of the expressiongetResultEnd() - getResultStart()
, but alsogetSourceEnd() - getSourceStart()
.
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getSourceContents
Get complete contents of the source file blamed for the current output region- Returns:
- complete contents of the source file blamed for the current
output region. This is the contents of
getSourcePath()
withingetSourceCommit()
. The source contents is temporarily available as an artifact of the blame algorithm. Most applications will want the result contents for display to users.
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getResultContents
Get complete file contents of the result file blame is annotating- Returns:
- complete file contents of the result file blame is annotating.
This value is accessible only after being configured and only
immediately before the first call to
next()
. Returns null if the path does not exist. - Throws:
IOException
- repository cannot be read.IllegalStateException
-next()
has already been invoked.
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close
public void close()Release the current blame session.
- Specified by:
close
in interfaceAutoCloseable
- Since:
- 4.0
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find
- Throws:
IOException
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isFile
private static final boolean isFile(int rawMode) -
findRename
private DiffEntry findRename(RevCommit parent, RevCommit commit, PathFilter path) throws IOException - Throws:
IOException
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isRename
-