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package org.eclipse.jgit.merge;
import java.io.IOException;
import org.eclipse.jgit.dircache.DirCache;
import org.eclipse.jgit.dircache.DirCacheBuilder;
import org.eclipse.jgit.dircache.DirCacheEntry;
import org.eclipse.jgit.errors.UnmergedPathException;
import org.eclipse.jgit.lib.FileMode;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.NameConflictTreeWalk;
/**
* Merges two commits together in-memory, ignoring any working directory.
* <p>
* The strategy chooses a path from one of the two input trees if the path is
* unchanged in the other relative to their common merge base tree. This is a
* trivial 3-way merge (at the file path level only).
* <p>
* Modifications of the same file path (content and/or file mode) by both input
* trees will cause a merge conflict, as this strategy does not attempt to merge
* file contents.
*/
public class StrategySimpleTwoWayInCore extends ThreeWayMergeStrategy {
/** Create a new instance of the strategy. */
protected StrategySimpleTwoWayInCore() {
//
}
@Override
public String getName() {
return "simple-two-way-in-core"; //$NON-NLS-1$
}
@Override
public ThreeWayMerger newMerger(final Repository db) {
return new InCoreMerger(db);
}
@Override
public ThreeWayMerger newMerger(Repository db, boolean inCore) {
// This class is always inCore, so ignore the parameter
return newMerger(db);
}
private static class InCoreMerger extends ThreeWayMerger {
private static final int T_BASE = 0;
private static final int T_OURS = 1;
private static final int T_THEIRS = 2;
private final NameConflictTreeWalk tw;
private final DirCache cache;
private DirCacheBuilder builder;
private ObjectId resultTree;
InCoreMerger(final Repository local) {
super(local);
tw = new NameConflictTreeWalk(reader);
cache = DirCache.newInCore();
}
@Override
protected boolean mergeImpl() throws IOException {
tw.addTree(mergeBase());
tw.addTree(sourceTrees[0]);
tw.addTree(sourceTrees[1]);
boolean hasConflict = false;
builder = cache.builder();
while (tw.next()) {
final int modeO = tw.getRawMode(T_OURS);
final int modeT = tw.getRawMode(T_THEIRS);
if (modeO == modeT && tw.idEqual(T_OURS, T_THEIRS)) {
add(T_OURS, DirCacheEntry.STAGE_0);
continue;
}
final int modeB = tw.getRawMode(T_BASE);
if (modeB == modeO && tw.idEqual(T_BASE, T_OURS))
add(T_THEIRS, DirCacheEntry.STAGE_0);
else if (modeB == modeT && tw.idEqual(T_BASE, T_THEIRS))
add(T_OURS, DirCacheEntry.STAGE_0);
else {
if (nonTree(modeB)) {
add(T_BASE, DirCacheEntry.STAGE_1);
hasConflict = true;
}
if (nonTree(modeO)) {
add(T_OURS, DirCacheEntry.STAGE_2);
hasConflict = true;
}
if (nonTree(modeT)) {
add(T_THEIRS, DirCacheEntry.STAGE_3);
hasConflict = true;
}
if (tw.isSubtree())
tw.enterSubtree();
}
}
builder.finish();
builder = null;
if (hasConflict)
return false;
try {
ObjectInserter odi = getObjectInserter();
resultTree = cache.writeTree(odi);
odi.flush();
return true;
} catch (UnmergedPathException upe) {
resultTree = null;
return false;
}
}
private static boolean nonTree(final int mode) {
return mode != 0 && !FileMode.TREE.equals(mode);
}
private void add(final int tree, final int stage) throws IOException {
final AbstractTreeIterator i = getTree(tree);
if (i != null) {
if (FileMode.TREE.equals(tw.getRawMode(tree))) {
builder.addTree(tw.getRawPath(), stage, reader, tw
.getObjectId(tree));
} else {
final DirCacheEntry e;
e = new DirCacheEntry(tw.getRawPath(), stage);
e.setObjectIdFromRaw(i.idBuffer(), i.idOffset());
e.setFileMode(tw.getFileMode(tree));
builder.add(e);
}
}
}
private AbstractTreeIterator getTree(final int tree) {
return tw.getTree(tree, AbstractTreeIterator.class);
}
@Override
public ObjectId getResultTreeId() {
return resultTree;
}
}
}