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/*
 * Copyright (C) 2010, Christian Halstrick ,
 * Copyright (C) 2010-2012, Matthias Sohn 
 * Copyright (C) 2012, Research In Motion Limited
 * 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.merge;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.eclipse.jgit.diff.DiffAlgorithm;
import org.eclipse.jgit.diff.DiffAlgorithm.SupportedAlgorithm;
import org.eclipse.jgit.diff.RawText;
import org.eclipse.jgit.diff.RawTextComparator;
import org.eclipse.jgit.diff.Sequence;
import org.eclipse.jgit.dircache.DirCache;
import org.eclipse.jgit.dircache.DirCacheBuildIterator;
import org.eclipse.jgit.dircache.DirCacheBuilder;
import org.eclipse.jgit.dircache.DirCacheCheckout;
import org.eclipse.jgit.dircache.DirCacheEntry;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.IndexWriteException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.errors.NoWorkTreeException;
import org.eclipse.jgit.internal.JGitText;
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.ObjectReader;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevTree;
import org.eclipse.jgit.treewalk.AbstractTreeIterator;
import org.eclipse.jgit.treewalk.CanonicalTreeParser;
import org.eclipse.jgit.treewalk.NameConflictTreeWalk;
import org.eclipse.jgit.treewalk.TreeWalk;
import org.eclipse.jgit.treewalk.WorkingTreeIterator;
import org.eclipse.jgit.util.FS;
import org.eclipse.jgit.util.FileUtils;

/**
 * A three-way merger performing a content-merge if necessary
 */
public class ResolveMerger extends ThreeWayMerger {
	/**
	 * If the merge fails (means: not stopped because of unresolved conflicts)
	 * this enum is used to explain why it failed
	 */
	public enum MergeFailureReason {
		/** the merge failed because of a dirty index */
		DIRTY_INDEX,
		/** the merge failed because of a dirty workingtree */
		DIRTY_WORKTREE,
		/** the merge failed because of a file could not be deleted */
		COULD_NOT_DELETE
	}

	/**
	 * The tree walk which we'll iterate over to merge entries.
	 *
	 * @since 3.4
	 */
	protected NameConflictTreeWalk tw;

	/**
	 * string versions of a list of commit SHA1s
	 *
	 * @since 3.0
	 */
	protected String commitNames[];

	/**
	 * Index of the base tree within the {@link #tw tree walk}.
	 *
	 * @since 3.4
	 */
	protected static final int T_BASE = 0;

	/**
	 * Index of our tree in withthe {@link #tw tree walk}.
	 *
	 * @since 3.4
	 */
	protected static final int T_OURS = 1;

	/**
	 * Index of their tree within the {@link #tw tree walk}.
	 *
	 * @since 3.4
	 */
	protected static final int T_THEIRS = 2;

	/**
	 * Index of the index tree within the {@link #tw tree walk}.
	 *
	 * @since 3.4
	 */
	protected static final int T_INDEX = 3;

	/**
	 * Index of the working directory tree within the {@link #tw tree walk}.
	 *
	 * @since 3.4
	 */
	protected static final int T_FILE = 4;

	/**
	 * Builder to update the cache during this merge.
	 *
	 * @since 3.4
	 */
	protected DirCacheBuilder builder;

	/**
	 * merge result as tree
	 *
	 * @since 3.0
	 */
	protected ObjectId resultTree;

	/**
	 * Paths that could not be merged by this merger because of an unsolvable
	 * conflict.
	 *
	 * @since 3.4
	 */
	protected List unmergedPaths = new ArrayList();

	/**
	 * Files modified during this merge operation.
	 *
	 * @since 3.4
	 */
	protected List modifiedFiles = new LinkedList();

	/**
	 * If the merger has nothing to do for a file but check it out at the end of
	 * the operation, it can be added here.
	 *
	 * @since 3.4
	 */
	protected Map toBeCheckedOut = new HashMap();

	/**
	 * Paths in this list will be deleted from the local copy at the end of the
	 * operation.
	 *
	 * @since 3.4
	 */
	protected List toBeDeleted = new ArrayList();

	/**
	 * Low-level textual merge results. Will be passed on to the callers in case
	 * of conflicts.
	 *
	 * @since 3.4
	 */
	protected Map> mergeResults = new HashMap>();

	/**
	 * Paths for which the merge failed altogether.
	 *
	 * @since 3.4
	 */
	protected Map failingPaths = new HashMap();

	/**
	 * Updated as we merge entries of the tree walk. Tells us whether we should
	 * recurse into the entry if it is a subtree.
	 *
	 * @since 3.4
	 */
	protected boolean enterSubtree;

	/**
	 * Set to true if this merge should work in-memory. The repos dircache and
	 * workingtree are not touched by this method. Eventually needed files are
	 * created as temporary files and a new empty, in-memory dircache will be
	 * used instead the repo's one. Often used for bare repos where the repo
	 * doesn't even have a workingtree and dircache.
	 * @since 3.0
	 */
	protected boolean inCore;

	/**
	 * Set to true if this merger should use the default dircache of the
	 * repository and should handle locking and unlocking of the dircache. If
	 * this merger should work in-core or if an explicit dircache was specified
	 * during construction then this field is set to false.
	 * @since 3.0
	 */
	protected boolean implicitDirCache;

	/**
	 * Directory cache
	 * @since 3.0
	 */
	protected DirCache dircache;

	/**
	 * The iterator to access the working tree. If set to null this
	 * merger will not touch the working tree.
	 * @since 3.0
	 */
	protected WorkingTreeIterator workingTreeIterator;

	/**
	 * our merge algorithm
	 * @since 3.0
	 */
	protected MergeAlgorithm mergeAlgorithm;

	/**
	 * @param local
	 * @param inCore
	 */
	protected ResolveMerger(Repository local, boolean inCore) {
		super(local);
		SupportedAlgorithm diffAlg = local.getConfig().getEnum(
				ConfigConstants.CONFIG_DIFF_SECTION, null,
				ConfigConstants.CONFIG_KEY_ALGORITHM,
				SupportedAlgorithm.HISTOGRAM);
		mergeAlgorithm = new MergeAlgorithm(DiffAlgorithm.getAlgorithm(diffAlg));
		commitNames = new String[] { "BASE", "OURS", "THEIRS" }; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
		this.inCore = inCore;

		if (inCore) {
			implicitDirCache = false;
			dircache = DirCache.newInCore();
		} else {
			implicitDirCache = true;
		}
	}

	/**
	 * @param local
	 */
	protected ResolveMerger(Repository local) {
		this(local, false);
	}

	@Override
	protected boolean mergeImpl() throws IOException {
		if (implicitDirCache)
			dircache = getRepository().lockDirCache();

		try {
			return mergeTrees(mergeBase(), sourceTrees[0], sourceTrees[1]);
		} finally {
			if (implicitDirCache)
				dircache.unlock();
		}
	}

	private void checkout() throws NoWorkTreeException, IOException {
		ObjectReader r = db.getObjectDatabase().newReader();
		try {
			for (Map.Entry entry : toBeCheckedOut
					.entrySet()) {
				File f = new File(db.getWorkTree(), entry.getKey());
				createDir(f.getParentFile());
				DirCacheCheckout.checkoutEntry(db, f, entry.getValue(), r);
				modifiedFiles.add(entry.getKey());
			}
			// Iterate in reverse so that "folder/file" is deleted before
			// "folder". Otherwise this could result in a failing path because
			// of a non-empty directory, for which delete() would fail.
			for (int i = toBeDeleted.size() - 1; i >= 0; i--) {
				String fileName = toBeDeleted.get(i);
				File f = new File(db.getWorkTree(), fileName);
				if (!f.delete())
					if (!f.isDirectory())
						failingPaths.put(fileName,
								MergeFailureReason.COULD_NOT_DELETE);
				modifiedFiles.add(fileName);
			}
		} finally {
			r.release();
		}
	}

	private void createDir(File f) throws IOException {
		if (!db.getFS().isDirectory(f) && !f.mkdirs()) {
			File p = f;
			while (p != null && !db.getFS().exists(p))
				p = p.getParentFile();
			if (p == null || db.getFS().isDirectory(p))
				throw new IOException(JGitText.get().cannotCreateDirectory);
			FileUtils.delete(p);
			if (!f.mkdirs())
				throw new IOException(JGitText.get().cannotCreateDirectory);
		}
	}

	/**
	 * Reverts the worktree after an unsuccessful merge. We know that for all
	 * modified files the old content was in the old index and the index
	 * contained only stage 0. In case if inCore operation just clear the
	 * history of modified files.
	 *
	 * @throws IOException
	 * @throws CorruptObjectException
	 * @throws NoWorkTreeException
	 * @since 3.4
	 */
	protected void cleanUp() throws NoWorkTreeException,
			CorruptObjectException,
			IOException {
		if (inCore) {
			modifiedFiles.clear();
			return;
		}

		DirCache dc = db.readDirCache();
		ObjectReader or = db.getObjectDatabase().newReader();
		Iterator mpathsIt=modifiedFiles.iterator();
		while(mpathsIt.hasNext()) {
			String mpath=mpathsIt.next();
			DirCacheEntry entry = dc.getEntry(mpath);
			if (entry == null)
				continue;
			FileOutputStream fos = new FileOutputStream(new File(
					db.getWorkTree(), mpath));
			try {
				or.open(entry.getObjectId()).copyTo(fos);
			} finally {
				fos.close();
			}
			mpathsIt.remove();
		}
	}

	/**
	 * adds a new path with the specified stage to the index builder
	 *
	 * @param path
	 * @param p
	 * @param stage
	 * @param lastMod
	 * @param len
	 * @return the entry which was added to the index
	 */
	private DirCacheEntry add(byte[] path, CanonicalTreeParser p, int stage,
			long lastMod, long len) {
		if (p != null && !p.getEntryFileMode().equals(FileMode.TREE)) {
			DirCacheEntry e = new DirCacheEntry(path, stage);
			e.setFileMode(p.getEntryFileMode());
			e.setObjectId(p.getEntryObjectId());
			e.setLastModified(lastMod);
			e.setLength(len);
			builder.add(e);
			return e;
		}
		return null;
	}

	/**
	 * adds a entry to the index builder which is a copy of the specified
	 * DirCacheEntry
	 *
	 * @param e
	 *            the entry which should be copied
	 *
	 * @return the entry which was added to the index
	 */
	private DirCacheEntry keep(DirCacheEntry e) {
		DirCacheEntry newEntry = new DirCacheEntry(e.getPathString(),
				e.getStage());
		newEntry.setFileMode(e.getFileMode());
		newEntry.setObjectId(e.getObjectId());
		newEntry.setLastModified(e.getLastModified());
		newEntry.setLength(e.getLength());
		builder.add(newEntry);
		return newEntry;
	}

	/**
	 * Processes one path and tries to merge. This method will do all do all
	 * trivial (not content) merges and will also detect if a merge will fail.
	 * The merge will fail when one of the following is true
	 * 
    *
  • the index entry does not match the entry in ours. When merging one * branch into the current HEAD, ours will point to HEAD and theirs will * point to the other branch. It is assumed that the index matches the HEAD * because it will only not match HEAD if it was populated before the merge * operation. But the merge commit should not accidentally contain * modifications done before the merge. Check the git read-tree documentation for further explanations.
  • *
  • A conflict was detected and the working-tree file is dirty. When a * conflict is detected the content-merge algorithm will try to write a * merged version into the working-tree. If the file is dirty we would * override unsaved data.
  • * * @param base * the common base for ours and theirs * @param ours * the ours side of the merge. When merging a branch into the * HEAD ours will point to HEAD * @param theirs * the theirs side of the merge. When merging a branch into the * current HEAD theirs will point to the branch which is merged * into HEAD. * @param index * the index entry * @param work * the file in the working tree * @return false if the merge will fail because the index entry * didn't match ours or the working-dir file was dirty and a * conflict occurred * @throws MissingObjectException * @throws IncorrectObjectTypeException * @throws CorruptObjectException * @throws IOException * @since 3.4 */ protected boolean processEntry(CanonicalTreeParser base, CanonicalTreeParser ours, CanonicalTreeParser theirs, DirCacheBuildIterator index, WorkingTreeIterator work) throws MissingObjectException, IncorrectObjectTypeException, CorruptObjectException, IOException { enterSubtree = true; final int modeO = tw.getRawMode(T_OURS); final int modeT = tw.getRawMode(T_THEIRS); final int modeB = tw.getRawMode(T_BASE); if (modeO == 0 && modeT == 0 && modeB == 0) // File is either untracked or new, staged but uncommitted return true; if (isIndexDirty()) return false; DirCacheEntry ourDce = null; if (index == null || index.getDirCacheEntry() == null) { // create a fake DCE, but only if ours is valid. ours is kept only // in case it is valid, so a null ourDce is ok in all other cases. if (nonTree(modeO)) { ourDce = new DirCacheEntry(tw.getRawPath()); ourDce.setObjectId(tw.getObjectId(T_OURS)); ourDce.setFileMode(tw.getFileMode(T_OURS)); } } else { ourDce = index.getDirCacheEntry(); } if (nonTree(modeO) && nonTree(modeT) && tw.idEqual(T_OURS, T_THEIRS)) { // OURS and THEIRS have equal content. Check the file mode if (modeO == modeT) { // content and mode of OURS and THEIRS are equal: it doesn't // matter which one we choose. OURS is chosen. Since the index // is clean (the index matches already OURS) we can keep the existing one keep(ourDce); // no checkout needed! return true; } else { // same content but different mode on OURS and THEIRS. // Try to merge the mode and report an error if this is // not possible. int newMode = mergeFileModes(modeB, modeO, modeT); if (newMode != FileMode.MISSING.getBits()) { if (newMode == modeO) // ours version is preferred keep(ourDce); else { // the preferred version THEIRS has a different mode // than ours. Check it out! if (isWorktreeDirty(work, ourDce)) return false; // we know about length and lastMod only after we have written the new content. // This will happen later. Set these values to 0 for know. DirCacheEntry e = add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_0, 0, 0); toBeCheckedOut.put(tw.getPathString(), e); } return true; } else { // FileModes are not mergeable. We found a conflict on modes. // For conflicting entries we don't know lastModified and length. add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0); add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0); unmergedPaths.add(tw.getPathString()); mergeResults.put( tw.getPathString(), new MergeResult(Collections . emptyList())); } return true; } } if (nonTree(modeO) && modeB == modeT && tw.idEqual(T_BASE, T_THEIRS)) { // THEIRS was not changed compared to BASE. All changes must be in // OURS. OURS is chosen. We can keep the existing entry. keep(ourDce); // no checkout needed! return true; } if (modeB == modeO && tw.idEqual(T_BASE, T_OURS)) { // OURS was not changed compared to BASE. All changes must be in // THEIRS. THEIRS is chosen. // Check worktree before checking out THEIRS if (isWorktreeDirty(work, ourDce)) return false; if (nonTree(modeT)) { // we know about length and lastMod only after we have written // the new content. // This will happen later. Set these values to 0 for know. DirCacheEntry e = add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_0, 0, 0); if (e != null) toBeCheckedOut.put(tw.getPathString(), e); return true; } else if (modeT == 0 && modeB != 0) { // we want THEIRS ... but THEIRS contains the deletion of the // file. Also, do not complain if the file is already deleted // locally. This complements the test in isWorktreeDirty() for // the same case. if (tw.getTreeCount() > T_FILE && tw.getRawMode(T_FILE) == 0) return true; toBeDeleted.add(tw.getPathString()); return true; } } if (tw.isSubtree()) { // file/folder conflicts: here I want to detect only file/folder // conflict between ours and theirs. file/folder conflicts between // base/index/workingTree and something else are not relevant or // detected later if (nonTree(modeO) && !nonTree(modeT)) { if (nonTree(modeB)) add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0); unmergedPaths.add(tw.getPathString()); enterSubtree = false; return true; } if (nonTree(modeT) && !nonTree(modeO)) { if (nonTree(modeB)) add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0); unmergedPaths.add(tw.getPathString()); enterSubtree = false; return true; } // ours and theirs are both folders or both files (and treewalk // tells us we are in a subtree because of index or working-dir). // If they are both folders no content-merge is required - we can // return here. if (!nonTree(modeO)) return true; // ours and theirs are both files, just fall out of the if block // and do the content merge } if (nonTree(modeO) && nonTree(modeT)) { // Check worktree before modifying files if (isWorktreeDirty(work, ourDce)) return false; // Don't attempt to resolve submodule link conflicts if (isGitLink(modeO) || isGitLink(modeT)) { add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0); add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0); unmergedPaths.add(tw.getPathString()); return true; } MergeResult result = contentMerge(base, ours, theirs); File of = writeMergedFile(result); updateIndex(base, ours, theirs, result, of); if (result.containsConflicts()) unmergedPaths.add(tw.getPathString()); modifiedFiles.add(tw.getPathString()); } else if (modeO != modeT) { // OURS or THEIRS has been deleted if (((modeO != 0 && !tw.idEqual(T_BASE, T_OURS)) || (modeT != 0 && !tw .idEqual(T_BASE, T_THEIRS)))) { add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0); DirCacheEntry e = add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0); // OURS was deleted checkout THEIRS if (modeO == 0) { // Check worktree before checking out THEIRS if (isWorktreeDirty(work, ourDce)) return false; if (nonTree(modeT)) { if (e != null) toBeCheckedOut.put(tw.getPathString(), e); } } unmergedPaths.add(tw.getPathString()); // generate a MergeResult for the deleted file mergeResults.put(tw.getPathString(), contentMerge(base, ours, theirs)); } } return true; } /** * Does the content merge. The three texts base, ours and theirs are * specified with {@link CanonicalTreeParser}. If any of the parsers is * specified as null then an empty text will be used instead. * * @param base * @param ours * @param theirs * * @return the result of the content merge * @throws IOException */ private MergeResult contentMerge(CanonicalTreeParser base, CanonicalTreeParser ours, CanonicalTreeParser theirs) throws IOException { RawText baseText = base == null ? RawText.EMPTY_TEXT : getRawText( base.getEntryObjectId(), db); RawText ourText = ours == null ? RawText.EMPTY_TEXT : getRawText( ours.getEntryObjectId(), db); RawText theirsText = theirs == null ? RawText.EMPTY_TEXT : getRawText( theirs.getEntryObjectId(), db); return (mergeAlgorithm.merge(RawTextComparator.DEFAULT, baseText, ourText, theirsText)); } private boolean isIndexDirty() { if (inCore) return false; final int modeI = tw.getRawMode(T_INDEX); final int modeO = tw.getRawMode(T_OURS); // Index entry has to match ours to be considered clean final boolean isDirty = nonTree(modeI) && !(modeO == modeI && tw.idEqual(T_INDEX, T_OURS)); if (isDirty) failingPaths .put(tw.getPathString(), MergeFailureReason.DIRTY_INDEX); return isDirty; } private boolean isWorktreeDirty(WorkingTreeIterator work, DirCacheEntry ourDce) throws IOException { if (work == null) return false; final int modeF = tw.getRawMode(T_FILE); final int modeO = tw.getRawMode(T_OURS); // Worktree entry has to match ours to be considered clean boolean isDirty; if (ourDce != null) isDirty = work.isModified(ourDce, true, reader); else { isDirty = work.isModeDifferent(modeO); if (!isDirty && nonTree(modeF)) isDirty = !tw.idEqual(T_FILE, T_OURS); } // Ignore existing empty directories if (isDirty && modeF == FileMode.TYPE_TREE && modeO == FileMode.TYPE_MISSING) isDirty = false; if (isDirty) failingPaths.put(tw.getPathString(), MergeFailureReason.DIRTY_WORKTREE); return isDirty; } /** * Updates the index after a content merge has happened. If no conflict has * occurred this includes persisting the merged content to the object * database. In case of conflicts this method takes care to write the * correct stages to the index. * * @param base * @param ours * @param theirs * @param result * @param of * @throws FileNotFoundException * @throws IOException */ private void updateIndex(CanonicalTreeParser base, CanonicalTreeParser ours, CanonicalTreeParser theirs, MergeResult result, File of) throws FileNotFoundException, IOException { if (result.containsConflicts()) { // a conflict occurred, the file will contain conflict markers // the index will be populated with the three stages and only the // workdir (if used) contains the halfways merged content add(tw.getRawPath(), base, DirCacheEntry.STAGE_1, 0, 0); add(tw.getRawPath(), ours, DirCacheEntry.STAGE_2, 0, 0); add(tw.getRawPath(), theirs, DirCacheEntry.STAGE_3, 0, 0); mergeResults.put(tw.getPathString(), result); } else { // no conflict occurred, the file will contain fully merged content. // the index will be populated with the new merged version DirCacheEntry dce = new DirCacheEntry(tw.getPathString()); int newMode = mergeFileModes(tw.getRawMode(0), tw.getRawMode(1), tw.getRawMode(2)); // set the mode for the new content. Fall back to REGULAR_FILE if // you can't merge modes of OURS and THEIRS dce.setFileMode((newMode == FileMode.MISSING.getBits()) ? FileMode.REGULAR_FILE : FileMode.fromBits(newMode)); dce.setLastModified(of.lastModified()); dce.setLength((int) of.length()); InputStream is = new FileInputStream(of); try { dce.setObjectId(getObjectInserter().insert( Constants.OBJ_BLOB, of.length(), is)); } finally { is.close(); if (inCore) FileUtils.delete(of); } builder.add(dce); } } /** * Writes merged file content to the working tree. In case {@link #inCore} * is set and we don't have a working tree the content is written to a * temporary file * * @param result * the result of the content merge * @return the file to which the merged content was written * @throws FileNotFoundException * @throws IOException */ private File writeMergedFile(MergeResult result) throws FileNotFoundException, IOException { MergeFormatter fmt = new MergeFormatter(); File of = null; FileOutputStream fos; if (!inCore) { File workTree = db.getWorkTree(); if (workTree == null) // TODO: This should be handled by WorkingTreeIterators which // support write operations throw new UnsupportedOperationException(); FS fs = db.getFS(); of = new File(workTree, tw.getPathString()); File parentFolder = of.getParentFile(); if (!fs.exists(parentFolder)) parentFolder.mkdirs(); fos = new FileOutputStream(of); try { fmt.formatMerge(fos, result, Arrays.asList(commitNames), Constants.CHARACTER_ENCODING); } finally { fos.close(); } } else if (!result.containsConflicts()) { // When working inCore, only trivial merges can be handled, // so we generate objects only in conflict free cases of = File.createTempFile("merge_", "_temp", null); //$NON-NLS-1$ //$NON-NLS-2$ fos = new FileOutputStream(of); try { fmt.formatMerge(fos, result, Arrays.asList(commitNames), Constants.CHARACTER_ENCODING); } finally { fos.close(); } } return of; } /** * Try to merge filemodes. If only ours or theirs have changed the mode * (compared to base) we choose that one. If ours and theirs have equal * modes return that one. If also that is not the case the modes are not * mergeable. Return {@link FileMode#MISSING} int that case. * * @param modeB * filemode found in BASE * @param modeO * filemode found in OURS * @param modeT * filemode found in THEIRS * * @return the merged filemode or {@link FileMode#MISSING} in case of a * conflict */ private int mergeFileModes(int modeB, int modeO, int modeT) { if (modeO == modeT) return modeO; if (modeB == modeO) // Base equal to Ours -> chooses Theirs if that is not missing return (modeT == FileMode.MISSING.getBits()) ? modeO : modeT; if (modeB == modeT) // Base equal to Theirs -> chooses Ours if that is not missing return (modeO == FileMode.MISSING.getBits()) ? modeT : modeO; return FileMode.MISSING.getBits(); } private static RawText getRawText(ObjectId id, Repository db) throws IOException { if (id.equals(ObjectId.zeroId())) return new RawText(new byte[] {}); return new RawText(db.open(id, Constants.OBJ_BLOB).getCachedBytes()); } private static boolean nonTree(final int mode) { return mode != 0 && !FileMode.TREE.equals(mode); } private static boolean isGitLink(final int mode) { return FileMode.GITLINK.equals(mode); } @Override public ObjectId getResultTreeId() { return (resultTree == null) ? null : resultTree.toObjectId(); } /** * @param commitNames * the names of the commits as they would appear in conflict * markers */ public void setCommitNames(String[] commitNames) { this.commitNames = commitNames; } /** * @return the names of the commits as they would appear in conflict * markers. */ public String[] getCommitNames() { return commitNames; } /** * @return the paths with conflicts. This is a subset of the files listed * by {@link #getModifiedFiles()} */ public List getUnmergedPaths() { return unmergedPaths; } /** * @return the paths of files which have been modified by this merge. A * file will be modified if a content-merge works on this path or if * the merge algorithm decides to take the theirs-version. This is a * superset of the files listed by {@link #getUnmergedPaths()}. */ public List getModifiedFiles() { return modifiedFiles; } /** * @return a map which maps the paths of files which have to be checked out * because the merge created new fully-merged content for this file * into the index. This means: the merge wrote a new stage 0 entry * for this path. */ public Map getToBeCheckedOut() { return toBeCheckedOut; } /** * @return the mergeResults */ public Map> getMergeResults() { return mergeResults; } /** * @return lists paths causing this merge to fail (not stopped because of a * conflict). null is returned if this merge didn't * fail. */ public Map getFailingPaths() { return (failingPaths.size() == 0) ? null : failingPaths; } /** * Returns whether this merge failed (i.e. not stopped because of a * conflict) * * @return true if a failure occurred, false * otherwise */ public boolean failed() { return failingPaths.size() > 0; } /** * Sets the DirCache which shall be used by this merger. If the DirCache is * not set explicitly and if this merger doesn't work in-core, this merger * will implicitly get and lock a default DirCache. If the DirCache is * explicitly set the caller is responsible to lock it in advance. Finally * the merger will call {@link DirCache#commit()} which requires that the * DirCache is locked. If the {@link #mergeImpl()} returns without throwing * an exception the lock will be released. In case of exceptions the caller * is responsible to release the lock. * * @param dc * the DirCache to set */ public void setDirCache(DirCache dc) { this.dircache = dc; implicitDirCache = false; } /** * Sets the WorkingTreeIterator to be used by this merger. If no * WorkingTreeIterator is set this merger will ignore the working tree and * fail if a content merge is necessary. *

    * TODO: enhance WorkingTreeIterator to support write operations. Then this * merger will be able to merge with a different working tree abstraction. * * @param workingTreeIterator * the workingTreeIt to set */ public void setWorkingTreeIterator(WorkingTreeIterator workingTreeIterator) { this.workingTreeIterator = workingTreeIterator; } /** * The resolve conflict way of three way merging * * @param baseTree * @param headTree * @param mergeTree * @return whether the trees merged cleanly * @throws IOException * @since 3.0 */ protected boolean mergeTrees(AbstractTreeIterator baseTree, RevTree headTree, RevTree mergeTree) throws IOException { builder = dircache.builder(); DirCacheBuildIterator buildIt = new DirCacheBuildIterator(builder); tw = new NameConflictTreeWalk(db); tw.addTree(baseTree); tw.addTree(headTree); tw.addTree(mergeTree); tw.addTree(buildIt); if (workingTreeIterator != null) tw.addTree(workingTreeIterator); if (!mergeTreeWalk(tw)) { return false; } if (!inCore) { // No problem found. The only thing left to be done is to // checkout all files from "theirs" which have been selected to // go into the new index. checkout(); // All content-merges are successfully done. If we can now write the // new index we are on quite safe ground. Even if the checkout of // files coming from "theirs" fails the user can work around such // failures by checking out the index again. if (!builder.commit()) { cleanUp(); throw new IndexWriteException(); } builder = null; } else { builder.finish(); builder = null; } if (getUnmergedPaths().isEmpty() && !failed()) { resultTree = dircache.writeTree(getObjectInserter()); return true; } else { resultTree = null; return false; } } /** * Process the given TreeWalk's entries. * * @param treeWalk * The walk to iterate over. * @return Whether the trees merged cleanly. * @throws IOException * @since 3.4 */ protected boolean mergeTreeWalk(TreeWalk treeWalk) throws IOException { boolean hasWorkingTreeIterator = tw.getTreeCount() > T_FILE; while (treeWalk.next()) { if (!processEntry( treeWalk.getTree(T_BASE, CanonicalTreeParser.class), treeWalk.getTree(T_OURS, CanonicalTreeParser.class), treeWalk.getTree(T_THEIRS, CanonicalTreeParser.class), treeWalk.getTree(T_INDEX, DirCacheBuildIterator.class), hasWorkingTreeIterator ? treeWalk.getTree(T_FILE, WorkingTreeIterator.class) : null)) { cleanUp(); return false; } if (treeWalk.isSubtree() && enterSubtree) treeWalk.enterSubtree(); } return true; } }





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