org.eclipse.jgit.diff
Class DiffFormatter

java.lang.Object
  org.eclipse.jgit.diff.DiffFormatter

Direct Known Subclasses:

PatchIdDiffFormatter

public class DiffFormatter
extends Object

Format a Git style patch script.

Constructor Summary

DiffFormatter(OutputStream out)
Create a new formatter with a default level of context.

Method Summary

void	flush() Flush the underlying output stream of this formatter.
void	format(AbstractTreeIterator a, AbstractTreeIterator b) Format the differences between two trees.
void	format(AnyObjectId a, AnyObjectId b) Format the differences between two trees.
void	format(DiffEntry ent) Format a patch script for one file entry.
void	format(EditList edits, RawText a, RawText b) Formats a list of edits in unified diff format
void	format(FileHeader head, RawText a, RawText b) Format a patch script, reusing a previously parsed FileHeader.
void	format(List<? extends DiffEntry> entries) Format a patch script from a list of difference entries.
void	format(RevTree a, RevTree b) Format the differences between two trees.
protected void	formatGitDiffFirstHeaderLine(ByteArrayOutputStream o, DiffEntry.ChangeType type, String oldPath, String newPath) Output the first header line
protected void	formatIndexLine(OutputStream o, DiffEntry ent)
String	getNewPrefix() Get the prefix applied in front of new file paths.
String	getOldPrefix() Get the prefix applied in front of old file paths.
protected OutputStream	getOutputStream()
TreeFilter	getPathFilter()
RenameDetector	getRenameDetector()
boolean	isDetectRenames()
void	release() Release the internal ObjectReader state.
List<DiffEntry>	scan(AbstractTreeIterator a, AbstractTreeIterator b) Determine the differences between two trees.
List<DiffEntry>	scan(AnyObjectId a, AnyObjectId b) Determine the differences between two trees.
List<DiffEntry>	scan(RevTree a, RevTree b) Determine the differences between two trees.
void	setAbbreviationLength(int count) Change the number of digits to show in an ObjectId.
void	setBinaryFileThreshold(int threshold) Set maximum file size for text files.
void	setContext(int lineCount) Change the number of lines of context to display.
void	setDetectRenames(boolean on) Enable or disable rename detection.
void	setDiffAlgorithm(DiffAlgorithm alg) Set the algorithm that constructs difference output.
void	setDiffComparator(RawTextComparator cmp) Set the line equivalence function for text file differences.
void	setNewPrefix(String prefix) Set the prefix applied in front of new file paths.
void	setOldPrefix(String prefix) Set the prefix applied in front of old file paths.
void	setPathFilter(TreeFilter filter) Set the filter to produce only specific paths.
void	setProgressMonitor(ProgressMonitor pm) Set the progress monitor for long running rename detection.
void	setRepository(Repository repository) Set the repository the formatter can load object contents from.
FileHeader	toFileHeader(DiffEntry ent) Creates a FileHeader representing the given DiffEntry
protected void	writeAddedLine(RawText text, int line) Output an added line.
protected void	writeContextLine(RawText text, int line) Output a line of context (unmodified line).
protected void	writeHunkHeader(int aStartLine, int aEndLine, int bStartLine, int bEndLine) Output a hunk header
protected void	writeLine(char prefix, RawText text, int cur) Write a standard patch script line.
protected void	writeRemovedLine(RawText text, int line) Output a removed line

Methods inherited from class java.lang.Object

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

Constructor Detail

DiffFormatter

public DiffFormatter(OutputStream out)

Create a new formatter with a default level of context.

Parameters:

out - the stream the formatter will write line data to. This stream should have buffering arranged by the caller, as many small writes are performed to it.

Method Detail

getOutputStream

protected OutputStream getOutputStream()

Returns:

the stream we are outputting data to.

setRepository

public void setRepository(Repository repository)

Set the repository the formatter can load object contents from. Once a repository has been set, the formatter must be released to ensure the internal ObjectReader is able to release its resources.

Parameters:

repository - source repository holding referenced objects.

setContext

public void setContext(int lineCount)

Change the number of lines of context to display.

Parameters:

lineCount - number of lines of context to see before the first modification and after the last modification within a hunk of the modified file.

setAbbreviationLength

public void setAbbreviationLength(int count)

Change the number of digits to show in an ObjectId.

Parameters:

count - number of digits to show in an ObjectId.

setDiffAlgorithm

public void setDiffAlgorithm(DiffAlgorithm alg)

Set the algorithm that constructs difference output.

Parameters:

alg - the algorithm to produce text file differences.

See Also:

HistogramDiff

setDiffComparator

public void setDiffComparator(RawTextComparator cmp)

Set the line equivalence function for text file differences.

Parameters:

cmp - The equivalence function used to determine if two lines of text are identical. The function can be changed to ignore various types of whitespace.

See Also:

RawTextComparator.DEFAULT, RawTextComparator.WS_IGNORE_ALL, RawTextComparator.WS_IGNORE_CHANGE, RawTextComparator.WS_IGNORE_LEADING, RawTextComparator.WS_IGNORE_TRAILING

setBinaryFileThreshold

public void setBinaryFileThreshold(int threshold)

Set maximum file size for text files. Files larger than this size will be treated as though they are binary and not text. Default is .

Parameters:

threshold - the limit, in bytes. Files larger than this size will be assumed to be binary, even if they aren't.

setOldPrefix

public void setOldPrefix(String prefix)

Set the prefix applied in front of old file paths.

Parameters:

prefix - the prefix in front of old paths. Typically this is the standard string "a/", but may be any prefix desired by the caller. Must not be null. Use the empty string to have no prefix at all.

getOldPrefix

public String getOldPrefix()

Get the prefix applied in front of old file paths.

Returns:

the prefix

Since:

2.0

setNewPrefix

public void setNewPrefix(String prefix)

Set the prefix applied in front of new file paths.

Parameters:

prefix - the prefix in front of new paths. Typically this is the standard string "b/", but may be any prefix desired by the caller. Must not be null. Use the empty string to have no prefix at all.

getNewPrefix

public String getNewPrefix()

Get the prefix applied in front of new file paths.

Returns:

the prefix

Since:

2.0

isDetectRenames

public boolean isDetectRenames()

Returns:

true if rename detection is enabled.

setDetectRenames

public void setDetectRenames(boolean on)

Enable or disable rename detection. Before enabling rename detection the repository must be set with setRepository(Repository). Once enabled the detector can be configured away from its defaults by obtaining the instance directly from getRenameDetector() and invoking configuration.

Parameters:

on - if rename detection should be enabled.

getRenameDetector

public RenameDetector getRenameDetector()

Returns:

the rename detector if rename detection is enabled.

setProgressMonitor

public void setProgressMonitor(ProgressMonitor pm)

Set the progress monitor for long running rename detection.

Parameters:

pm - progress monitor to receive rename detection status through.

setPathFilter

public void setPathFilter(TreeFilter filter)

Set the filter to produce only specific paths. If the filter is an instance of FollowFilter, the filter path will be updated during successive scan or format invocations. The updated path can be obtained from getPathFilter().

Parameters:

filter - the tree filter to apply.

getPathFilter

public TreeFilter getPathFilter()

Returns:

the current path filter.

flush

public void flush()
           throws IOException

Flush the underlying output stream of this formatter.

Throws:

IOException - the stream's own flush method threw an exception.

release

public void release()

Release the internal ObjectReader state.

scan

public List<DiffEntry> scan(AnyObjectId a,
                            AnyObjectId b)
                     throws IOException

Determine the differences between two trees. No output is created, instead only the file paths that are different are returned. Callers may choose to format these paths themselves, or convert them into FileHeader instances with a complete edit list by calling toFileHeader(DiffEntry).

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Returns:

the paths that are different.

Throws:

IOException - trees cannot be read or file contents cannot be read.

scan

public List<DiffEntry> scan(RevTree a,
                            RevTree b)
                     throws IOException

Determine the differences between two trees. No output is created, instead only the file paths that are different are returned. Callers may choose to format these paths themselves, or convert them into FileHeader instances with a complete edit list by calling toFileHeader(DiffEntry).

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Returns:

the paths that are different.

Throws:

IOException - trees cannot be read or file contents cannot be read.

scan

public List<DiffEntry> scan(AbstractTreeIterator a,
                            AbstractTreeIterator b)
                     throws IOException

Determine the differences between two trees. No output is created, instead only the file paths that are different are returned. Callers may choose to format these paths themselves, or convert them into FileHeader instances with a complete edit list by calling toFileHeader(DiffEntry).

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Returns:

the paths that are different.

Throws:

IOException - trees cannot be read or file contents cannot be read.

format

public void format(AnyObjectId a,
                   AnyObjectId b)
            throws IOException

Format the differences between two trees. The patch is expressed as instructions to modify a to make it b.

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Throws:

IOException - trees cannot be read, file contents cannot be read, or the patch cannot be output.

format

public void format(RevTree a,
                   RevTree b)
            throws IOException

Format the differences between two trees. The patch is expressed as instructions to modify a to make it b.

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Throws:

IOException - trees cannot be read, file contents cannot be read, or the patch cannot be output.

format

public void format(AbstractTreeIterator a,
                   AbstractTreeIterator b)
            throws IOException

Format the differences between two trees. The patch is expressed as instructions to modify a to make it b.

Parameters:

a - the old (or previous) side.

b - the new (or updated) side.

Throws:

IOException - trees cannot be read, file contents cannot be read, or the patch cannot be output.

format

public void format(List<? extends DiffEntry> entries)
            throws IOException

Format a patch script from a list of difference entries. Requires scan(AbstractTreeIterator, AbstractTreeIterator) to have been called first.

Parameters:

entries - entries describing the affected files.

Throws:

IOException - a file's content cannot be read, or the output stream cannot be written to.

format

public void format(DiffEntry ent)
            throws IOException

Format a patch script for one file entry.

Parameters:

ent - the entry to be formatted.

Throws:

IOException - a file's content cannot be read, or the output stream cannot be written to.

format

public void format(FileHeader head,
                   RawText a,
                   RawText b)
            throws IOException

Format a patch script, reusing a previously parsed FileHeader.

This formatter is primarily useful for editing an existing patch script to increase or reduce the number of lines of context within the script. All header lines are reused as-is from the supplied FileHeader.

Parameters:

head - existing file header containing the header lines to copy.

a - text source for the pre-image version of the content. This must match the content of DiffEntry.getOldId().

b - text source for the post-image version of the content. This must match the content of DiffEntry.getNewId().

Throws:

IOException - writing to the supplied stream failed.

format

public void format(EditList edits,
                   RawText a,
                   RawText b)
            throws IOException

Formats a list of edits in unified diff format

Parameters:

edits - some differences which have been calculated between A and B

a - the text A which was compared

b - the text B which was compared

Throws:

IOException

writeContextLine

protected void writeContextLine(RawText text,
                                int line)
                         throws IOException

Output a line of context (unmodified line).

Parameters:

text - RawText for accessing raw data

line - the line number within text

Throws:

IOException

writeAddedLine

protected void writeAddedLine(RawText text,
                              int line)
                       throws IOException

Output an added line.

Parameters:

text - RawText for accessing raw data

line - the line number within text

Throws:

IOException

writeRemovedLine

protected void writeRemovedLine(RawText text,
                                int line)
                         throws IOException

Output a removed line

Parameters:

text - RawText for accessing raw data

line - the line number within text

Throws:

IOException

writeHunkHeader

protected void writeHunkHeader(int aStartLine,
                               int aEndLine,
                               int bStartLine,
                               int bEndLine)
                        throws IOException

Output a hunk header

Parameters:

aStartLine - within first source

aEndLine - within first source

bStartLine - within second source

bEndLine - within second source

Throws:

IOException

writeLine

protected void writeLine(char prefix,
                         RawText text,
                         int cur)
                  throws IOException

Write a standard patch script line.

Parameters:

prefix - prefix before the line, typically '-', '+', ' '.

text - the text object to obtain the line from.

cur - line number to output.

Throws:

IOException - the stream threw an exception while writing to it.

toFileHeader

public FileHeader toFileHeader(DiffEntry ent)
                        throws IOException,
                               CorruptObjectException,
                               MissingObjectException

Creates a FileHeader representing the given DiffEntry

This method does not use the OutputStream associated with this DiffFormatter instance. It is therefore safe to instantiate this DiffFormatter instance with a DisabledOutputStream if this method is the only one that will be used.

Parameters:

ent - the DiffEntry to create the FileHeader for

Returns:

a FileHeader representing the DiffEntry. The FileHeader's buffer will contain only the header of the diff output. It will also contain one HunkHeader.

Throws:

IOException - the stream threw an exception while writing to it, or one of the blobs referenced by the DiffEntry could not be read.

CorruptObjectException - one of the blobs referenced by the DiffEntry is corrupt.

MissingObjectException - one of the blobs referenced by the DiffEntry is missing.

formatGitDiffFirstHeaderLine

protected void formatGitDiffFirstHeaderLine(ByteArrayOutputStream o,
                                            DiffEntry.ChangeType type,
                                            String oldPath,
                                            String newPath)
                                     throws IOException

Output the first header line

Parameters:

o - The stream the formatter will write the first header line to

type - The DiffEntry.ChangeType

oldPath - old path to the file

newPath - new path to the file

Throws:

IOException - the stream threw an exception while writing to it.

formatIndexLine

protected void formatIndexLine(OutputStream o,
                               DiffEntry ent)
                        throws IOException

Parameters:

o - the stream the formatter will write line data to

ent - the DiffEntry to create the FileHeader for

Throws:

IOException - writing to the supplied stream failed.