/*
* Copyright (C) 2009, Google Inc.
* Copyright (C) 2008-2009, Johannes E. Schindelin <johannes.schindelin@gmx.de>
* and other copyright owners as documented in the project's IP log.
*
* This program and the accompanying materials are made available
* under the terms of the Eclipse Distribution License v1.0 which
* accompanies this distribution, is reproduced below, and is
* available at http://www.eclipse.org/org/documents/edl-v10.php
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* - Neither the name of the Eclipse Foundation, Inc. nor the
* names of its contributors may be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.eclipse.jgit.diff;
import static org.eclipse.jgit.diff.DiffEntry.ChangeType.ADD;
import static org.eclipse.jgit.diff.DiffEntry.ChangeType.COPY;
import static org.eclipse.jgit.diff.DiffEntry.ChangeType.DELETE;
import static org.eclipse.jgit.diff.DiffEntry.ChangeType.MODIFY;
import static org.eclipse.jgit.diff.DiffEntry.ChangeType.RENAME;
import static org.eclipse.jgit.diff.DiffEntry.Side.NEW;
import static org.eclipse.jgit.diff.DiffEntry.Side.OLD;
import static org.eclipse.jgit.lib.Constants.encode;
import static org.eclipse.jgit.lib.Constants.encodeASCII;
import static org.eclipse.jgit.lib.FileMode.GITLINK;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import org.eclipse.jgit.JGitText;
import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
import org.eclipse.jgit.diff.DiffEntry.ChangeType;
import org.eclipse.jgit.dircache.DirCacheIterator;
import org.eclipse.jgit.errors.AmbiguousObjectException;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.AbbreviatedObjectId;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ConfigConstants;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectLoader;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.lib.ProgressMonitor;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.patch.FileHeader;
import org.eclipse.jgit.patch.FileHeader.PatchType;
import org.eclipse.jgit.patch.HunkHeader;
import org.eclipse.jgit.revwalk.FollowFilter;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.storage.pack.PackConfig;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.WorkingTreeIterator;
import org.eclipse.jgit.treewalk.filter.AndTreeFilter;
import org.eclipse.jgit.treewalk.filter.IndexDiffFilter;
import org.eclipse.jgit.treewalk.filter.NotIgnoredFilter;
import org.eclipse.jgit.treewalk.filter.PathFilter;
import org.eclipse.jgit.treewalk.filter.TreeFilter;
import org.eclipse.jgit.util.QuotedString;
import org.eclipse.jgit.util.io.DisabledOutputStream;
/**
* Format a Git style patch script.
*/
public class DiffFormatter {
private static final int DEFAULT_BINARY_FILE_THRESHOLD = PackConfig.DEFAULT_BIG_FILE_THRESHOLD;
private static final byte[] noNewLine = encodeASCII("\\ No newline at end of file\n");
/** Magic return content indicating it is empty or no content present. */
private static final byte[] EMPTY = new byte[] {};
/** Magic return indicating the content is binary. */
private static final byte[] BINARY = new byte[] {};
private final OutputStream out;
private Repository db;
private ObjectReader reader;
private int context = 3;
private int abbreviationLength = 7;
private DiffAlgorithm diffAlgorithm;
private RawTextComparator comparator = RawTextComparator.DEFAULT;
private int binaryFileThreshold = DEFAULT_BINARY_FILE_THRESHOLD;
private String oldPrefix = "a/";
private String newPrefix = "b/";
private TreeFilter pathFilter = TreeFilter.ALL;
private RenameDetector renameDetector;
private ProgressMonitor progressMonitor;
private ContentSource.Pair source;
/**
* Create a new formatter with a default level of context.
*
* @param 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.
*/
public DiffFormatter(OutputStream out) {
this.out = out;
}
/** @return the stream we are outputting data to. */
protected OutputStream getOutputStream() {
return out;
}
/**
* 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.
*
* @param repository
* source repository holding referenced objects.
*/
public void setRepository(Repository repository) {
if (reader != null)
reader.release();
db = repository;
reader = db.newObjectReader();
ContentSource cs = ContentSource.create(reader);
source = new ContentSource.Pair(cs, cs);
DiffConfig dc = db.getConfig().get(DiffConfig.KEY);
if (dc.isNoPrefix()) {
setOldPrefix("");
setNewPrefix("");
}
setDetectRenames(dc.isRenameDetectionEnabled());
diffAlgorithm = DiffAlgorithm.getAlgorithm(db.getConfig().getEnum(
ConfigConstants.CONFIG_DIFF_SECTION, null,
ConfigConstants.CONFIG_KEY_ALGORITHM,
SupportedAlgorithm.HISTOGRAM));
}
/**
* Change the number of lines of context to display.
*
* @param lineCount
* number of lines of context to see before the first
* modification and after the last modification within a hunk of
* the modified file.
*/
public void setContext(final int lineCount) {
if (lineCount < 0)
throw new IllegalArgumentException(
JGitText.get().contextMustBeNonNegative);
context = lineCount;
}
/**
* Change the number of digits to show in an ObjectId.
*
* @param count
* number of digits to show in an ObjectId.
*/
public void setAbbreviationLength(final int count) {
if (count < 0)
throw new IllegalArgumentException(
JGitText.get().abbreviationLengthMustBeNonNegative);
abbreviationLength = count;
}
/**
* Set the algorithm that constructs difference output.
*
* @param alg
* the algorithm to produce text file differences.
* @see HistogramDiff
*/
public void setDiffAlgorithm(DiffAlgorithm alg) {
diffAlgorithm = alg;
}
/**
* Set the line equivalence function for text file differences.
*
* @param 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 RawTextComparator#DEFAULT
* @see RawTextComparator#WS_IGNORE_ALL
* @see RawTextComparator#WS_IGNORE_CHANGE
* @see RawTextComparator#WS_IGNORE_LEADING
* @see RawTextComparator#WS_IGNORE_TRAILING
*/
public void setDiffComparator(RawTextComparator cmp) {
comparator = cmp;
}
/**
* 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 {@value #DEFAULT_BINARY_FILE_THRESHOLD} .
*
* @param threshold
* the limit, in bytes. Files larger than this size will be
* assumed to be binary, even if they aren't.
*/
public void setBinaryFileThreshold(int threshold) {
this.binaryFileThreshold = threshold;
}
/**
* Set the prefix applied in front of old file paths.
*
* @param prefix
* the prefix in front of old paths. Typically this is the
* standard string {@code "a/"}, but may be any prefix desired by
* the caller. Must not be null. Use the empty string to have no
* prefix at all.
*/
public void setOldPrefix(String prefix) {
oldPrefix = prefix;
}
/**
* Set the prefix applied in front of new file paths.
*
* @param prefix
* the prefix in front of new paths. Typically this is the
* standard string {@code "b/"}, but may be any prefix desired by
* the caller. Must not be null. Use the empty string to have no
* prefix at all.
*/
public void setNewPrefix(String prefix) {
newPrefix = prefix;
}
/** @return true if rename detection is enabled. */
public boolean isDetectRenames() {
return renameDetector != null;
}
/**
* Enable or disable rename detection.
*
* Before enabling rename detection the repository must be set with
* {@link #setRepository(Repository)}. Once enabled the detector can be
* configured away from its defaults by obtaining the instance directly from
* {@link #getRenameDetector()} and invoking configuration.
*
* @param on
* if rename detection should be enabled.
*/
public void setDetectRenames(boolean on) {
if (on && renameDetector == null) {
assertHaveRepository();
renameDetector = new RenameDetector(db);
} else if (!on)
renameDetector = null;
}
/** @return the rename detector if rename detection is enabled. */
public RenameDetector getRenameDetector() {
return renameDetector;
}
/**
* Set the progress monitor for long running rename detection.
*
* @param pm
* progress monitor to receive rename detection status through.
*/
public void setProgressMonitor(ProgressMonitor pm) {
progressMonitor = pm;
}
/**
* Set the filter to produce only specific paths.
*
* If the filter is an instance of {@link FollowFilter}, the filter path
* will be updated during successive scan or format invocations. The updated
* path can be obtained from {@link #getPathFilter()}.
*
* @param filter
* the tree filter to apply.
*/
public void setPathFilter(TreeFilter filter) {
pathFilter = filter != null ? filter : TreeFilter.ALL;
}
/** @return the current path filter. */
public TreeFilter getPathFilter() {
return pathFilter;
}
/**
* Flush the underlying output stream of this formatter.
*
* @throws IOException
* the stream's own flush method threw an exception.
*/
public void flush() throws IOException {
out.flush();
}
/** Release the internal ObjectReader state. */
public void release() {
if (reader != null)
reader.release();
}
/**
* 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 {@link FileHeader} instances with a complete edit list by
* calling {@link #toFileHeader(DiffEntry)}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @return the paths that are different.
* @throws IOException
* trees cannot be read or file contents cannot be read.
*/
public List<DiffEntry> scan(AnyObjectId a, AnyObjectId b)
throws IOException {
assertHaveRepository();
RevWalk rw = new RevWalk(reader);
return scan(rw.parseTree(a), rw.parseTree(b));
}
/**
* 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 {@link FileHeader} instances with a complete edit list by
* calling {@link #toFileHeader(DiffEntry)}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @return the paths that are different.
* @throws IOException
* trees cannot be read or file contents cannot be read.
*/
public List<DiffEntry> scan(RevTree a, RevTree b) throws IOException {
assertHaveRepository();
CanonicalTreeParser aParser = new CanonicalTreeParser();
CanonicalTreeParser bParser = new CanonicalTreeParser();
aParser.reset(reader, a);
bParser.reset(reader, b);
return scan(aParser, bParser);
}
/**
* 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 {@link FileHeader} instances with a complete edit list by
* calling {@link #toFileHeader(DiffEntry)}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @return the paths that are different.
* @throws IOException
* trees cannot be read or file contents cannot be read.
*/
public List<DiffEntry> scan(AbstractTreeIterator a, AbstractTreeIterator b)
throws IOException {
assertHaveRepository();
TreeWalk walk = new TreeWalk(reader);
walk.addTree(a);
walk.addTree(b);
walk.setRecursive(true);
TreeFilter filter = getDiffTreeFilterFor(a, b);
if (pathFilter instanceof FollowFilter) {
walk.setFilter(AndTreeFilter.create(
PathFilter.create(((FollowFilter) pathFilter).getPath()),
filter));
} else {
walk.setFilter(AndTreeFilter.create(pathFilter, filter));
}
source = new ContentSource.Pair(source(a), source(b));
List<DiffEntry> files = DiffEntry.scan(walk);
if (pathFilter instanceof FollowFilter && isAdd(files)) {
// The file we are following was added here, find where it
// came from so we can properly show the rename or copy,
// then continue digging backwards.
//
a.reset();
b.reset();
walk.reset();
walk.addTree(a);
walk.addTree(b);
walk.setFilter(filter);
if (renameDetector == null)
setDetectRenames(true);
files = updateFollowFilter(detectRenames(DiffEntry.scan(walk)));
} else if (renameDetector != null)
files = detectRenames(files);
return files;
}
private static TreeFilter getDiffTreeFilterFor(AbstractTreeIterator a,
AbstractTreeIterator b) {
if (a instanceof DirCacheIterator && b instanceof WorkingTreeIterator)
return new IndexDiffFilter(0, 1);
if (a instanceof WorkingTreeIterator && b instanceof DirCacheIterator)
return new IndexDiffFilter(1, 0);
TreeFilter filter = TreeFilter.ANY_DIFF;
if (a instanceof WorkingTreeIterator)
filter = AndTreeFilter.create(new NotIgnoredFilter(0), filter);
if (b instanceof WorkingTreeIterator)
filter = AndTreeFilter.create(new NotIgnoredFilter(1), filter);
return filter;
}
private ContentSource source(AbstractTreeIterator iterator) {
if (iterator instanceof WorkingTreeIterator)
return ContentSource.create((WorkingTreeIterator) iterator);
return ContentSource.create(reader);
}
private List<DiffEntry> detectRenames(List<DiffEntry> files)
throws IOException {
renameDetector.reset();
renameDetector.addAll(files);
return renameDetector.compute(reader, progressMonitor);
}
private boolean isAdd(List<DiffEntry> files) {
String oldPath = ((FollowFilter) pathFilter).getPath();
for (DiffEntry ent : files) {
if (ent.getChangeType() == ADD && ent.getNewPath().equals(oldPath))
return true;
}
return false;
}
private List<DiffEntry> updateFollowFilter(List<DiffEntry> files) {
String oldPath = ((FollowFilter) pathFilter).getPath();
for (DiffEntry ent : files) {
if (isRename(ent) && ent.getNewPath().equals(oldPath)) {
pathFilter = FollowFilter.create(ent.getOldPath());
return Collections.singletonList(ent);
}
}
return Collections.emptyList();
}
private static boolean isRename(DiffEntry ent) {
return ent.getChangeType() == RENAME || ent.getChangeType() == COPY;
}
/**
* Format the differences between two trees.
*
* The patch is expressed as instructions to modify {@code a} to make it
* {@code b}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @throws IOException
* trees cannot be read, file contents cannot be read, or the
* patch cannot be output.
*/
public void format(AnyObjectId a, AnyObjectId b) throws IOException {
format(scan(a, b));
}
/**
* Format the differences between two trees.
*
* The patch is expressed as instructions to modify {@code a} to make it
* {@code b}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @throws IOException
* trees cannot be read, file contents cannot be read, or the
* patch cannot be output.
*/
public void format(RevTree a, RevTree b) throws IOException {
format(scan(a, b));
}
/**
* Format the differences between two trees.
*
* The patch is expressed as instructions to modify {@code a} to make it
* {@code b}.
*
* @param a
* the old (or previous) side.
* @param b
* the new (or updated) side.
* @throws IOException
* trees cannot be read, file contents cannot be read, or the
* patch cannot be output.
*/
public void format(AbstractTreeIterator a, AbstractTreeIterator b)
throws IOException {
format(scan(a, b));
}
/**
* Format a patch script from a list of difference entries. Requires
* {@link #scan(AbstractTreeIterator, AbstractTreeIterator)} to have been
* called first.
*
* @param entries
* entries describing the affected files.
* @throws IOException
* a file's content cannot be read, or the output stream cannot
* be written to.
*/
public void format(List<? extends DiffEntry> entries) throws IOException {
for (DiffEntry ent : entries)
format(ent);
}
/**
* Format a patch script for one file entry.
*
* @param ent
* the entry to be formatted.
* @throws IOException
* a file's content cannot be read, or the output stream cannot
* be written to.
*/
public void format(DiffEntry ent) throws IOException {
FormatResult res = createFormatResult(ent);
format(res.header, res.a, res.b);
}
private void writeGitLinkDiffText(OutputStream o, DiffEntry ent)
throws IOException {
if (ent.getOldMode() == GITLINK) {
o.write(encodeASCII("-Subproject commit " + ent.getOldId().name()
+ "\n"));
}
if (ent.getNewMode() == GITLINK) {
o.write(encodeASCII("+Subproject commit " + ent.getNewId().name()
+ "\n"));
}
}
private String format(AbbreviatedObjectId id) {
if (id.isComplete() && db != null) {
try {
id = reader.abbreviate(id.toObjectId(), abbreviationLength);
} catch (IOException cannotAbbreviate) {
// Ignore this. We'll report the full identity.
}
}
return id.name();
}
private static String quotePath(String name) {
return QuotedString.GIT_PATH.quote(name);
}
/**
* Format a patch script, reusing a previously parsed FileHeader.
* <p>
* 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.
*
* @param head
* existing file header containing the header lines to copy.
* @param a
* text source for the pre-image version of the content. This
* must match the content of {@link FileHeader#getOldId()}.
* @param b
* text source for the post-image version of the content. This
* must match the content of {@link FileHeader#getNewId()}.
* @throws IOException
* writing to the supplied stream failed.
*/
public void format(final FileHeader head, final RawText a, final RawText b)
throws IOException {
// Reuse the existing FileHeader as-is by blindly copying its
// header lines, but avoiding its hunks. Instead we recreate
// the hunks from the text instances we have been supplied.
//
final int start = head.getStartOffset();
int end = head.getEndOffset();
if (!head.getHunks().isEmpty())
end = head.getHunks().get(0).getStartOffset();
out.write(head.getBuffer(), start, end - start);
if (head.getPatchType() == PatchType.UNIFIED)
format(head.toEditList(), a, b);
}
/**
* Formats a list of edits in unified diff format
*
* @param edits
* some differences which have been calculated between A and B
* @param a
* the text A which was compared
* @param b
* the text B which was compared
* @throws IOException
*/
public void format(final EditList edits, final RawText a, final RawText b)
throws IOException {
for (int curIdx = 0; curIdx < edits.size();) {
Edit curEdit = edits.get(curIdx);
final int endIdx = findCombinedEnd(edits, curIdx);
final Edit endEdit = edits.get(endIdx);
int aCur = Math.max(0, curEdit.getBeginA() - context);
int bCur = Math.max(0, curEdit.getBeginB() - context);
final int aEnd = Math.min(a.size(), endEdit.getEndA() + context);
final int bEnd = Math.min(b.size(), endEdit.getEndB() + context);
writeHunkHeader(aCur, aEnd, bCur, bEnd);
while (aCur < aEnd || bCur < bEnd) {
if (aCur < curEdit.getBeginA() || endIdx + 1 < curIdx) {
writeContextLine(a, aCur);
if (isEndOfLineMissing(a, aCur))
out.write(noNewLine);
aCur++;
bCur++;
} else if (aCur < curEdit.getEndA()) {
writeRemovedLine(a, aCur);
if (isEndOfLineMissing(a, aCur))
out.write(noNewLine);
aCur++;
} else if (bCur < curEdit.getEndB()) {
writeAddedLine(b, bCur);
if (isEndOfLineMissing(b, bCur))
out.write(noNewLine);
bCur++;
}
if (end(curEdit, aCur, bCur) && ++curIdx < edits.size())
curEdit = edits.get(curIdx);
}
}
}
/**
* Output a line of context (unmodified line).
*
* @param text
* RawText for accessing raw data
* @param line
* the line number within text
* @throws IOException
*/
protected void writeContextLine(final RawText text, final int line)
throws IOException {
writeLine(' ', text, line);
}
private boolean isEndOfLineMissing(final RawText text, final int line) {
return line + 1 == text.size() && text.isMissingNewlineAtEnd();
}
/**
* Output an added line.
*
* @param text
* RawText for accessing raw data
* @param line
* the line number within text
* @throws IOException
*/
protected void writeAddedLine(final RawText text, final int line)
throws IOException {
writeLine('+', text, line);
}
/**
* Output a removed line
*
* @param text
* RawText for accessing raw data
* @param line
* the line number within text
* @throws IOException
*/
protected void writeRemovedLine(final RawText text, final int line)
throws IOException {
writeLine('-', text, line);
}
/**
* Output a hunk header
*
* @param aStartLine
* within first source
* @param aEndLine
* within first source
* @param bStartLine
* within second source
* @param bEndLine
* within second source
* @throws IOException
*/
protected void writeHunkHeader(int aStartLine, int aEndLine,
int bStartLine, int bEndLine) throws IOException {
out.write('@');
out.write('@');
writeRange('-', aStartLine + 1, aEndLine - aStartLine);
writeRange('+', bStartLine + 1, bEndLine - bStartLine);
out.write(' ');
out.write('@');
out.write('@');
out.write('\n');
}
private void writeRange(final char prefix, final int begin, final int cnt)
throws IOException {
out.write(' ');
out.write(prefix);
switch (cnt) {
case 0:
// If the range is empty, its beginning number must be the
// line just before the range, or 0 if the range is at the
// start of the file stream. Here, begin is always 1 based,
// so an empty file would produce "0,0".
//
out.write(encodeASCII(begin - 1));
out.write(',');
out.write('0');
break;
case 1:
// If the range is exactly one line, produce only the number.
//
out.write(encodeASCII(begin));
break;
default:
out.write(encodeASCII(begin));
out.write(',');
out.write(encodeASCII(cnt));
break;
}
}
/**
* Write a standard patch script line.
*
* @param prefix
* prefix before the line, typically '-', '+', ' '.
* @param text
* the text object to obtain the line from.
* @param cur
* line number to output.
* @throws IOException
* the stream threw an exception while writing to it.
*/
protected void writeLine(final char prefix, final RawText text,
final int cur) throws IOException {
out.write(prefix);
text.writeLine(out, cur);
out.write('\n');
}
/**
* Creates a {@link FileHeader} representing the given {@link DiffEntry}
* <p>
* This method does not use the OutputStream associated with this
* DiffFormatter instance. It is therefore safe to instantiate this
* DiffFormatter instance with a {@link DisabledOutputStream} if this method
* is the only one that will be used.
*
* @param ent
* the DiffEntry to create the FileHeader for
* @return a FileHeader representing the DiffEntry. The FileHeader's buffer
* will contain only the header of the diff output. It will also
* contain one {@link 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.
* @throws CorruptObjectException
* one of the blobs referenced by the DiffEntry is corrupt.
* @throws MissingObjectException
* one of the blobs referenced by the DiffEntry is missing.
*/
public FileHeader toFileHeader(DiffEntry ent) throws IOException,
CorruptObjectException, MissingObjectException {
return createFormatResult(ent).header;
}
private static class FormatResult {
FileHeader header;
RawText a;
RawText b;
}
private FormatResult createFormatResult(DiffEntry ent) throws IOException,
CorruptObjectException, MissingObjectException {
final FormatResult res = new FormatResult();
ByteArrayOutputStream buf = new ByteArrayOutputStream();
final EditList editList;
final FileHeader.PatchType type;
formatHeader(buf, ent);
if (ent.getOldMode() == GITLINK || ent.getNewMode() == GITLINK) {
formatOldNewPaths(buf, ent);
writeGitLinkDiffText(buf, ent);
editList = new EditList();
type = PatchType.UNIFIED;
} else {
assertHaveRepository();
byte[] aRaw = open(OLD, ent);
byte[] bRaw = open(NEW, ent);
if (aRaw == BINARY || bRaw == BINARY //
|| RawText.isBinary(aRaw) || RawText.isBinary(bRaw)) {
formatOldNewPaths(buf, ent);
buf.write(encodeASCII("Binary files differ\n"));
editList = new EditList();
type = PatchType.BINARY;
} else {
res.a = new RawText(aRaw);
res.b = new RawText(bRaw);
editList = diff(res.a, res.b);
type = PatchType.UNIFIED;
switch (ent.getChangeType()) {
case RENAME:
case COPY:
if (!editList.isEmpty())
formatOldNewPaths(buf, ent);
break;
default:
formatOldNewPaths(buf, ent);
break;
}
}
}
res.header = new FileHeader(buf.toByteArray(), editList, type);
return res;
}
private EditList diff(RawText a, RawText b) {
return diffAlgorithm.diff(comparator, a, b);
}
private void assertHaveRepository() {
if (db == null)
throw new IllegalStateException(JGitText.get().repositoryIsRequired);
}
private byte[] open(DiffEntry.Side side, DiffEntry entry)
throws IOException {
if (entry.getMode(side) == FileMode.MISSING)
return EMPTY;
if (entry.getMode(side).getObjectType() != Constants.OBJ_BLOB)
return EMPTY;
if (isBinary(entry.getPath(side)))
return BINARY;
AbbreviatedObjectId id = entry.getId(side);
if (!id.isComplete()) {
Collection<ObjectId> ids = reader.resolve(id);
if (ids.size() == 1) {
id = AbbreviatedObjectId.fromObjectId(ids.iterator().next());
switch (side) {
case OLD:
entry.oldId = id;
break;
case NEW:
entry.newId = id;
break;
}
} else if (ids.size() == 0)
throw new MissingObjectException(id, Constants.OBJ_BLOB);
else
throw new AmbiguousObjectException(id, ids);
}
try {
ObjectLoader ldr = source.open(side, entry);
return ldr.getBytes(binaryFileThreshold);
} catch (LargeObjectException.ExceedsLimit overLimit) {
return BINARY;
} catch (LargeObjectException.ExceedsByteArrayLimit overLimit) {
return BINARY;
} catch (LargeObjectException.OutOfMemory tooBig) {
return BINARY;
} catch (LargeObjectException tooBig) {
tooBig.setObjectId(id.toObjectId());
throw tooBig;
}
}
private boolean isBinary(String path) {
return false;
}
private void formatHeader(ByteArrayOutputStream o, DiffEntry ent)
throws IOException {
final ChangeType type = ent.getChangeType();
final String oldp = ent.getOldPath();
final String newp = ent.getNewPath();
final FileMode oldMode = ent.getOldMode();
final FileMode newMode = ent.getNewMode();
o.write(encodeASCII("diff --git "));
o.write(encode(quotePath(oldPrefix + (type == ADD ? newp : oldp))));
o.write(' ');
o.write(encode(quotePath(newPrefix + (type == DELETE ? oldp : newp))));
o.write('\n');
switch (type) {
case ADD:
o.write(encodeASCII("new file mode "));
newMode.copyTo(o);
o.write('\n');
break;
case DELETE:
o.write(encodeASCII("deleted file mode "));
oldMode.copyTo(o);
o.write('\n');
break;
case RENAME:
o.write(encodeASCII("similarity index " + ent.getScore() + "%"));
o.write('\n');
o.write(encode("rename from " + quotePath(oldp)));
o.write('\n');
o.write(encode("rename to " + quotePath(newp)));
o.write('\n');
break;
case COPY:
o.write(encodeASCII("similarity index " + ent.getScore() + "%"));
o.write('\n');
o.write(encode("copy from " + quotePath(oldp)));
o.write('\n');
o.write(encode("copy to " + quotePath(newp)));
o.write('\n');
if (!oldMode.equals(newMode)) {
o.write(encodeASCII("new file mode "));
newMode.copyTo(o);
o.write('\n');
}
break;
case MODIFY:
if (0 < ent.getScore()) {
o.write(encodeASCII("dissimilarity index "
+ (100 - ent.getScore()) + "%"));
o.write('\n');
}
break;
}
if ((type == MODIFY || type == RENAME) && !oldMode.equals(newMode)) {
o.write(encodeASCII("old mode "));
oldMode.copyTo(o);
o.write('\n');
o.write(encodeASCII("new mode "));
newMode.copyTo(o);
o.write('\n');
}
if (!ent.getOldId().equals(ent.getNewId())) {
formatIndexLine(o, ent);
}
}
/**
* @param o
* the stream the formatter will write line data to
* @param ent
* the DiffEntry to create the FileHeader for
* @throws IOException
* writing to the supplied stream failed.
*/
protected void formatIndexLine(OutputStream o, DiffEntry ent)
throws IOException {
o.write(encodeASCII("index " //
+ format(ent.getOldId()) //
+ ".." //
+ format(ent.getNewId())));
if (ent.getOldMode().equals(ent.getNewMode())) {
o.write(' ');
ent.getNewMode().copyTo(o);
}
o.write('\n');
}
private void formatOldNewPaths(ByteArrayOutputStream o, DiffEntry ent)
throws IOException {
if (ent.oldId.equals(ent.newId))
return;
final String oldp;
final String newp;
switch (ent.getChangeType()) {
case ADD:
oldp = DiffEntry.DEV_NULL;
newp = quotePath(newPrefix + ent.getNewPath());
break;
case DELETE:
oldp = quotePath(oldPrefix + ent.getOldPath());
newp = DiffEntry.DEV_NULL;
break;
default:
oldp = quotePath(oldPrefix + ent.getOldPath());
newp = quotePath(newPrefix + ent.getNewPath());
break;
}
o.write(encode("--- " + oldp + "\n"));
o.write(encode("+++ " + newp + "\n"));
}
private int findCombinedEnd(final List<Edit> edits, final int i) {
int end = i + 1;
while (end < edits.size()
&& (combineA(edits, end) || combineB(edits, end)))
end++;
return end - 1;
}
private boolean combineA(final List<Edit> e, final int i) {
return e.get(i).getBeginA() - e.get(i - 1).getEndA() <= 2 * context;
}
private boolean combineB(final List<Edit> e, final int i) {
return e.get(i).getBeginB() - e.get(i - 1).getEndB() <= 2 * context;
}
private static boolean end(final Edit edit, final int a, final int b) {
return edit.getEndA() <= a && edit.getEndB() <= b;
}
}