Mercurial > hg4j

changeset 705:b4242b7e7dfe

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Merge command: implement conflict resolution alternatives
author Artem Tikhomirov <tikhomirov.artem@gmail.com>
date Thu, 15 Aug 2013 18:43:50 +0200
parents 7743a9c10bfa
children cd5c87d96315
files cmdline/org/tmatesoft/hg/console/Merge.java src/org/tmatesoft/hg/core/HgAddRemoveCommand.java src/org/tmatesoft/hg/core/HgCheckoutCommand.java src/org/tmatesoft/hg/core/HgCommitCommand.java src/org/tmatesoft/hg/core/HgMergeCommand.java src/org/tmatesoft/hg/core/HgPullCommand.java src/org/tmatesoft/hg/core/HgRevertCommand.java src/org/tmatesoft/hg/internal/CommitFacility.java src/org/tmatesoft/hg/internal/DirstateBuilder.java src/org/tmatesoft/hg/internal/FileUtils.java src/org/tmatesoft/hg/internal/Internals.java src/org/tmatesoft/hg/internal/MergeStateBuilder.java src/org/tmatesoft/hg/internal/WorkingDirFileWriter.java src/org/tmatesoft/hg/repo/HgMergeState.java src/org/tmatesoft/hg/util/Path.java
diffstat 15 files changed, 478 insertions(+), 107 deletions(-) [+]
line wrap: on
line diff
--- a/cmdline/org/tmatesoft/hg/console/Merge.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/cmdline/org/tmatesoft/hg/console/Merge.java	Thu Aug 15 18:43:50 2013 +0200
@@ -56,8 +56,8 @@
 
 	static class Dump implements HgMergeCommand.Mediator {
 
-		public void same(HgFileRevision first, HgFileRevision second, Resolver resolver) throws HgCallbackTargetException {
-			System.out.printf("Unchanged %s:%s", first.getPath(), first.getRevision().shortNotation());
+		public void same(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			System.out.printf("Unchanged %s:%s", rev.getPath(), rev.getRevision().shortNotation());
 		}
 
 		public void onlyA(HgFileRevision base, HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
--- a/src/org/tmatesoft/hg/core/HgAddRemoveCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgAddRemoveCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -18,7 +18,6 @@
 
 import java.util.LinkedHashSet;
 
-import org.tmatesoft.hg.internal.COWTransaction;
 import org.tmatesoft.hg.internal.DirstateBuilder;
 import org.tmatesoft.hg.internal.DirstateReader;
 import org.tmatesoft.hg.internal.Internals;
@@ -123,7 +122,7 @@
 				progress.worked(1);
 				cancellation.checkCancelled();
 			}
-			Transaction.Factory trFactory = new COWTransaction.Factory();
+			Transaction.Factory trFactory = implRepo.getTransactionFactory();
 			Transaction tr = trFactory.create(repo);
 			try {
 				dirstateBuilder.serialize(tr);
--- a/src/org/tmatesoft/hg/core/HgCheckoutCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgCheckoutCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -231,8 +231,8 @@
 				lastFileMode = workingDirWriter.fmode();
 				lastFileModificationTime = workingDirWriter.mtime();
 				return true;
-			} catch (IOException ex) {
-				failure = new HgIOException("Failed to write down file revision", ex, workingDirWriter.getDestinationFile());
+			} catch (HgIOException ex) {
+				failure = ex;
 			} catch (HgRuntimeException ex) {
 				failure = new HgLibraryFailureException(ex);
 			}
--- a/src/org/tmatesoft/hg/core/HgCommitCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgCommitCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -20,7 +20,6 @@
 
 import java.io.IOException;
 
-import org.tmatesoft.hg.internal.COWTransaction;
 import org.tmatesoft.hg.internal.CommitFacility;
 import org.tmatesoft.hg.internal.CompleteRepoLock;
 import org.tmatesoft.hg.internal.FileContentSupplier;
@@ -112,7 +111,8 @@
 				newRevision = Nodeid.NULL;
 				return new Outcome(Kind.Failure, "nothing to add");
 			}
-			CommitFacility cf = new CommitFacility(Internals.getInstance(repo), parentRevs[0], parentRevs[1]);
+			final Internals implRepo = Internals.getInstance(repo);
+			CommitFacility cf = new CommitFacility(implRepo, parentRevs[0], parentRevs[1]);
 			for (Path m : status.getModified()) {
 				HgDataFile df = repo.getFileNode(m);
 				cf.add(df, new WorkingCopyContent(df));
@@ -131,7 +131,7 @@
 			}
 			cf.branch(detectBranch());
 			cf.user(detectUser());
-			Transaction.Factory trFactory = new COWTransaction.Factory();
+			Transaction.Factory trFactory = implRepo.getTransactionFactory();
 			Transaction tr = trFactory.create(repo);
 			try {
 				newRevision = cf.commit(message, tr);
--- a/src/org/tmatesoft/hg/core/HgMergeCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgMergeCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -18,13 +18,23 @@
 
 import static org.tmatesoft.hg.repo.HgRepository.BAD_REVISION;
 
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
 import java.io.InputStream;
 
 import org.tmatesoft.hg.internal.Callback;
 import org.tmatesoft.hg.internal.CsetParamKeeper;
+import org.tmatesoft.hg.internal.DirstateBuilder;
+import org.tmatesoft.hg.internal.DirstateReader;
 import org.tmatesoft.hg.internal.Experimental;
+import org.tmatesoft.hg.internal.FileUtils;
+import org.tmatesoft.hg.internal.Internals;
 import org.tmatesoft.hg.internal.ManifestRevision;
+import org.tmatesoft.hg.internal.MergeStateBuilder;
 import org.tmatesoft.hg.internal.Pool;
+import org.tmatesoft.hg.internal.Transaction;
+import org.tmatesoft.hg.internal.WorkingDirFileWriter;
 import org.tmatesoft.hg.repo.HgChangelog;
 import org.tmatesoft.hg.repo.HgParentChildMap;
 import org.tmatesoft.hg.repo.HgRepository;
@@ -62,7 +72,7 @@
 		return this;
 	}
 
-	public void execute(Mediator mediator) throws HgCallbackTargetException, HgRepositoryLockException, HgLibraryFailureException, CancelledException {
+	public void execute(Mediator mediator) throws HgCallbackTargetException, HgRepositoryLockException, HgIOException, HgLibraryFailureException, CancelledException {
 		if (firstCset == BAD_REVISION || secondCset == BAD_REVISION || ancestorCset == BAD_REVISION) {
 			throw new IllegalArgumentException("Merge heads and their ancestors are not initialized");
 		}
@@ -71,65 +81,91 @@
 		try {
 			Pool<Nodeid> cacheRevs = new Pool<Nodeid>();
 			Pool<Path> cacheFiles = new Pool<Path>();
+
+			Internals implRepo = Internals.getInstance(repo);
+			final DirstateBuilder dirstateBuilder = new DirstateBuilder(implRepo);
+			dirstateBuilder.fillFrom(new DirstateReader(implRepo, new Path.SimpleSource(repo.getSessionContext().getPathFactory(), cacheFiles)));
+			final HgChangelog clog = repo.getChangelog();
+			dirstateBuilder.parents(clog.getRevision(firstCset), clog.getRevision(secondCset));
+			//
+			MergeStateBuilder mergeStateBuilder = new MergeStateBuilder(implRepo);
+
 			ManifestRevision m1, m2, ma;
 			m1 = new ManifestRevision(cacheRevs, cacheFiles).init(repo, firstCset);
 			m2 = new ManifestRevision(cacheRevs, cacheFiles).init(repo, secondCset);
 			ma = new ManifestRevision(cacheRevs, cacheFiles).init(repo, ancestorCset);
-			ResolverImpl resolver = new ResolverImpl();
-			for (Path f : m1.files()) {
-				Nodeid fileRevBase, fileRevA, fileRevB;
-				if (m2.contains(f)) {
-					fileRevA = m1.nodeid(f);
-					fileRevB = m2.nodeid(f);
-					fileRevBase = ma.contains(f) ? ma.nodeid(f) : null;
-					if (fileRevA.equals(fileRevB)) {
-						HgFileRevision fr = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
-						mediator.same(fr, fr, resolver);
-					} else if (fileRevBase == fileRevA) {
-						assert fileRevBase != null;
-						HgFileRevision frBase = new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
-						HgFileRevision frSecond= new HgFileRevision(repo, fileRevB, m2.flags(f), f);
-						mediator.fastForwardB(frBase, frSecond, resolver);
-					} else if (fileRevBase == fileRevB) {
-						assert fileRevBase != null;
-						HgFileRevision frBase = new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
-						HgFileRevision frFirst = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
-						mediator.fastForwardA(frBase, frFirst, resolver);
+			Transaction transaction = implRepo.getTransactionFactory().create(repo);
+			ResolverImpl resolver = new ResolverImpl(implRepo, dirstateBuilder, mergeStateBuilder);
+			try {
+				for (Path f : m1.files()) {
+					Nodeid fileRevBase, fileRevA, fileRevB;
+					if (m2.contains(f)) {
+						fileRevA = m1.nodeid(f);
+						fileRevB = m2.nodeid(f);
+						fileRevBase = ma.contains(f) ? ma.nodeid(f) : null;
+						if (fileRevA.equals(fileRevB)) {
+							HgFileRevision fr = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
+							resolver.presentState(f, fr, fr);
+							mediator.same(fr, resolver);
+						} else if (fileRevBase == fileRevA) {
+							assert fileRevBase != null;
+							HgFileRevision frBase = new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
+							HgFileRevision frSecond= new HgFileRevision(repo, fileRevB, m2.flags(f), f);
+							resolver.presentState(f, frBase, frSecond);
+							mediator.fastForwardB(frBase, frSecond, resolver);
+						} else if (fileRevBase == fileRevB) {
+							assert fileRevBase != null;
+							HgFileRevision frBase = new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
+							HgFileRevision frFirst = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
+							resolver.presentState(f, frFirst, frBase);
+							mediator.fastForwardA(frBase, frFirst, resolver);
+						} else {
+							HgFileRevision frBase = fileRevBase == null ? null : new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
+							HgFileRevision frFirst = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
+							HgFileRevision frSecond= new HgFileRevision(repo, fileRevB, m2.flags(f), f);
+							resolver.presentState(f, frFirst, frSecond);
+							mediator.resolve(frBase, frFirst, frSecond, resolver);
+						}
 					} else {
-						HgFileRevision frBase = fileRevBase == null ? null : new HgFileRevision(repo, fileRevBase, ma.flags(f), f);
-						HgFileRevision frFirst = new HgFileRevision(repo, fileRevA, m1.flags(f), f);
-						HgFileRevision frSecond= new HgFileRevision(repo, fileRevB, m2.flags(f), f);
-						mediator.resolve(frBase, frFirst, frSecond, resolver);
+						// m2 doesn't contain the file, either new in m1, or deleted in m2
+						HgFileRevision frFirst = new HgFileRevision(repo, m1.nodeid(f), m1.flags(f), f);
+						resolver.presentState(f, frFirst, null);
+						if (ma.contains(f)) {
+							// deleted in m2
+							HgFileRevision frBase = new HgFileRevision(repo, ma.nodeid(f), ma.flags(f), f);
+							mediator.onlyA(frBase, frFirst, resolver);
+						} else {
+							// new in m1
+							mediator.newInA(frFirst, resolver);
+						}
 					}
-				} else {
-					// m2 doesn't contain the file, either new in m1, or deleted in m2
-					HgFileRevision frFirst = new HgFileRevision(repo, m1.nodeid(f), m1.flags(f), f);
+					resolver.apply();
+				} // for m1 files
+				for (Path f : m2.files()) {
+					if (m1.contains(f)) {
+						continue;
+					}
+					HgFileRevision frSecond= new HgFileRevision(repo, m2.nodeid(f), m2.flags(f), f);
+					// file in m2 is either new or deleted in m1
+					resolver.presentState(f, null, frSecond);
 					if (ma.contains(f)) {
-						// deleted in m2
+						// deleted in m1
 						HgFileRevision frBase = new HgFileRevision(repo, ma.nodeid(f), ma.flags(f), f);
-						mediator.onlyA(frBase, frFirst, resolver);
+						mediator.onlyB(frBase, frSecond, resolver);
 					} else {
-						// new in m1
-						mediator.newInA(frFirst, resolver);
+						// new in m2
+						mediator.newInB(frSecond, resolver);
 					}
+					resolver.apply();
 				}
-				resolver.apply();
-			} // for m1 files
-			for (Path f : m2.files()) {
-				if (m1.contains(f)) {
-					continue;
-				}
-				HgFileRevision frSecond= new HgFileRevision(repo, m2.nodeid(f), m2.flags(f), f);
-				// file in m2 is either new or deleted in m1
-				if (ma.contains(f)) {
-					// deleted in m1
-					HgFileRevision frBase = new HgFileRevision(repo, ma.nodeid(f), ma.flags(f), f);
-					mediator.onlyB(frBase, frSecond, resolver);
-				} else {
-					// new in m2
-					mediator.newInB(frSecond, resolver);
-				}
-				resolver.apply();
+				resolver.serializeChanged(transaction);
+				transaction.commit();
+			} catch (HgRuntimeException ex) {
+				transaction.rollback();
+				throw ex;
+			} catch (HgIOException ex) {
+				transaction.rollback();
+				throw ex;
 			}
 		} catch (HgRuntimeException ex) {
 			throw new HgLibraryFailureException(ex);
@@ -160,18 +196,43 @@
 	}
 
 	/**
-	 * This is the way client code takes part in the merge process
+	 * This is the way client code takes part in the merge process. 
+	 * It's advised to subclass {@link MediatorBase} unless special treatment for regular cases is desired
 	 */
 	@Experimental(reason="Provisional API. Work in progress")
 	@Callback
 	public interface Mediator {
-		public void same(HgFileRevision first, HgFileRevision second, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file revisions are identical in both heads
+		 */
+		public void same(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file left in first/left/A trunk only, deleted in second/right/B trunk
+		 */
 		public void onlyA(HgFileRevision base, HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file left in second/right/B trunk only, deleted in first/left/A trunk
+		 */
 		public void onlyB(HgFileRevision base, HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file is missing in ancestor revision and second/right/B trunk, introduced in first/left/A trunk
+		 */
 		public void newInA(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file is missing in ancestor revision and first/left/A trunk, introduced in second/right/B trunk
+		 */
 		public void newInB(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file was changed in first/left/A trunk, unchanged in second/right/B trunk
+		 */
 		public void fastForwardA(HgFileRevision base, HgFileRevision first, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * file was changed in second/right/B trunk, unchanged in first/left/A trunk 
+		 */
 		public void fastForwardB(HgFileRevision base, HgFileRevision second, Resolver resolver) throws HgCallbackTargetException;
+		/**
+		 * File changed (or added, if base is <code>null</code>) in both trunks 
+		 */
 		public void resolve(HgFileRevision base, HgFileRevision first, HgFileRevision second, Resolver resolver) throws HgCallbackTargetException;
 	}
 
@@ -182,24 +243,170 @@
 	@Experimental(reason="Provisional API. Work in progress")
 	public interface Resolver {
 		public void use(HgFileRevision rev);
-		public void use(InputStream content);
+		/**
+		 * Replace current revision with stream content.
+		 * Note, callers are not expected to {@link InputStream#close()} this stream. 
+		 * It will be {@link InputStream#close() closed} at <b>Hg4J</b>'s discretion
+		 * not necessarily during invocation of this method. IOW, the library may decide to 
+		 * use this stream not right away, at some point of time later, and streams supplied
+		 * shall respect this.
+		 * 
+		 * @param content New content to replace current revision, shall not be <code>null</code> 
+		 * @throws IOException propagated exceptions from content
+		 */
+		public void use(InputStream content) throws IOException;
+		public void forget(HgFileRevision rev);
 		public void unresolved(); // record the file for later processing by 'hg resolve'
 	}
 
+	/**
+	 * Base mediator implementation, with regular resolution
+	 */
+	@Experimental(reason="Provisional API. Work in progress")
+	public abstract class MediatorBase implements Mediator {
+		public void same(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(rev);
+		}
+		public void onlyA(HgFileRevision base, HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(rev);
+		}
+		public void onlyB(HgFileRevision base, HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(rev);
+		}
+		public void newInA(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(rev);
+		}
+		public void newInB(HgFileRevision rev, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(rev);
+		}
+		public void fastForwardA(HgFileRevision base, HgFileRevision first, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(first);
+		}
+		public void fastForwardB(HgFileRevision base, HgFileRevision second, Resolver resolver) throws HgCallbackTargetException {
+			resolver.use(second);
+		}
+	}
+
 	private static class ResolverImpl implements Resolver {
-		void apply() {
+		
+		private final Internals repo;
+		private final DirstateBuilder dirstateBuilder;
+		private final MergeStateBuilder mergeStateBuilder;
+		private boolean changedDirstate;
+		private HgFileRevision revA;
+		private HgFileRevision revB;
+		private Path file;
+		// resolutions:
+		private HgFileRevision resolveUse, resolveForget;
+		private File resolveContent;
+		private boolean resolveMarkUnresolved;
+		
+		public ResolverImpl(Internals implRepo, DirstateBuilder dirstateBuilder, MergeStateBuilder mergeStateBuilder) {
+			repo = implRepo;
+			this.dirstateBuilder = dirstateBuilder;
+			this.mergeStateBuilder = mergeStateBuilder;
+			changedDirstate = false;
+		}
+		
+		void serializeChanged(Transaction tr) throws HgIOException {
+			if (changedDirstate) {
+				dirstateBuilder.serialize(tr);
+			}
+			mergeStateBuilder.serialize(tr);
+		}
+
+		void presentState(Path p, HgFileRevision revA, HgFileRevision revB) {
+			assert revA != null || revB != null;
+			file = p;
+			this.revA = revA;
+			this.revB = revB;
+			resolveUse = resolveForget = null;
+			resolveContent = null;
+			resolveMarkUnresolved = false;
+		}
+
+		void apply() throws HgIOException, HgRuntimeException {
+			if (resolveMarkUnresolved) {
+				mergeStateBuilder.unresolved(file);
+			} else if (resolveForget != null) {
+				if (resolveForget == revA) {
+					changedDirstate = true;
+					dirstateBuilder.recordRemoved(file);
+				}
+			} else if (resolveUse != null) {
+				if (resolveUse != revA) {
+					changedDirstate = true;
+					final WorkingDirFileWriter fw = new WorkingDirFileWriter(repo);
+					fw.processFile(resolveUse);
+					if (resolveUse == revB) {
+						dirstateBuilder.recordMergedFromP2(file);
+					} else {
+						dirstateBuilder.recordMerged(file, fw.fmode(), fw.mtime(), fw.bytesWritten());
+					}
+				} // if resolution is to use revA, nothing to do
+			} else if (resolveContent != null) {
+				changedDirstate = true;
+				// FIXME write content to file using transaction?
+				InputStream is;
+				try {
+					is = new FileInputStream(resolveContent);
+				} catch (IOException ex) {
+					throw new HgIOException("Failed to read temporary content", ex, resolveContent);
+				}
+				final WorkingDirFileWriter fw = new WorkingDirFileWriter(repo);
+				fw.processFile(file, is, revA == null ? revB.getFileFlags() : revA.getFileFlags());
+				// XXX if presentState(null, fileOnlyInB), and use(InputStream) - i.e.
+				// resolution is to add file with supplied content - shall I put 'Merged', MergedFromP2 or 'Added' into dirstate?
+				if (revA == null && revB != null) {
+					dirstateBuilder.recordMergedFromP2(file);
+				} else {
+					dirstateBuilder.recordMerged(file, fw.fmode(), fw.mtime(), fw.bytesWritten());
+				}
+			} else {
+				assert false;
+			}
 		}
 
 		public void use(HgFileRevision rev) {
-			// TODO Auto-generated method stub
+			if (rev == null) {
+				throw new IllegalArgumentException();
+			}
+			assert resolveContent == null;
+			assert resolveForget == null;
+			resolveUse = rev;
 		}
 
-		public void use(InputStream content) {
-			// TODO Auto-generated method stub
+		public void use(InputStream content) throws IOException {
+			if (content == null) {
+				throw new IllegalArgumentException();
+			}
+			assert resolveUse == null;
+			assert resolveForget == null;
+			try {
+				// cache new contents just to fail fast if there are troubles with content
+				final FileUtils fileUtils = new FileUtils(repo.getLog(), this);
+				resolveContent = fileUtils.createTempFile();
+				fileUtils.write(content, resolveContent);
+			} finally {
+				content.close();
+			}
+			// do not care deleting file in case of failure to allow analyze of the issue
+		}
+
+		public void forget(HgFileRevision rev) {
+			if (rev == null) {
+				throw new IllegalArgumentException();
+			}
+			if (rev != revA || rev != revB) {
+				throw new IllegalArgumentException("Can't forget revision which doesn't represent actual state in either merged trunk");
+			}
+			assert resolveUse == null;
+			assert resolveContent == null;
+			resolveForget = rev;
 		}
 
 		public void unresolved() {
-			// TODO Auto-generated method stub
+			resolveMarkUnresolved = true;
 		}
 	}
 }
--- a/src/org/tmatesoft/hg/core/HgPullCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgPullCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -21,7 +21,6 @@
 import java.util.List;
 
 import org.tmatesoft.hg.internal.AddRevInspector;
-import org.tmatesoft.hg.internal.COWTransaction;
 import org.tmatesoft.hg.internal.Internals;
 import org.tmatesoft.hg.internal.PhasesHelper;
 import org.tmatesoft.hg.internal.RepositoryComparator;
@@ -78,7 +77,7 @@
 			// add revisions to changelog, manifest, files
 			final Internals implRepo = HgInternals.getImplementationRepo(repo);
 			final AddRevInspector insp;
-			Transaction.Factory trFactory = new COWTransaction.Factory();
+			Transaction.Factory trFactory = implRepo.getTransactionFactory();
 			Transaction tr = trFactory.create(repo);
 			try {
 				incoming.inspectAll(insp = new AddRevInspector(implRepo, tr));
--- a/src/org/tmatesoft/hg/core/HgRevertCommand.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/core/HgRevertCommand.java	Thu Aug 15 18:43:50 2013 +0200
@@ -21,7 +21,6 @@
 import java.util.LinkedHashSet;
 import java.util.Set;
 
-import org.tmatesoft.hg.internal.COWTransaction;
 import org.tmatesoft.hg.internal.CsetParamKeeper;
 import org.tmatesoft.hg.internal.DirstateBuilder;
 import org.tmatesoft.hg.internal.DirstateReader;
@@ -160,7 +159,7 @@
 				progress.worked(1);
 				cancellation.checkCancelled();
 			}
-			Transaction.Factory trFactory = new COWTransaction.Factory();
+			Transaction.Factory trFactory = implRepo.getTransactionFactory();
 			Transaction tr = trFactory.create(repo);
 			try {
 				// TODO same code in HgAddRemoveCommand and similar in HgCommitCommand
--- a/src/org/tmatesoft/hg/internal/CommitFacility.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/internal/CommitFacility.java	Thu Aug 15 18:43:50 2013 +0200
@@ -212,7 +212,7 @@
 		}
 		// bring dirstate up to commit state, TODO share this code with HgAddRemoveCommand
 		final DirstateBuilder dirstateBuilder = new DirstateBuilder(repo);
-		dirstateBuilder.fillFrom(new DirstateReader(repo, new Path.SimpleSource()));
+		dirstateBuilder.fillFrom(new DirstateReader(repo, repo.getSessionContext().getPathFactory()));
 		for (Path p : removals) {
 			dirstateBuilder.recordRemoved(p);
 		}
--- a/src/org/tmatesoft/hg/internal/DirstateBuilder.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/internal/DirstateBuilder.java	Thu Aug 15 18:43:50 2013 +0200
@@ -92,6 +92,22 @@
 		removed.put(fname, n);
 	}
 	
+	public void recordMerged(Path fname, int fmode, int mtime, int bytesWritten) {
+		forget(fname);
+		merged.put(fname, new HgDirstate.Record(fmode, bytesWritten,mtime, fname, null));
+	}
+	
+	/**
+	 * From DirState wiki:
+	 * <p>"size is ... when the dirstate is in a merge state: -2 will *always* return dirty, it is used to mark a file that was cleanly picked from p2"
+	 * and  
+	 * <p>"Additional meta status...'np2': merged from other parent (status == 'n', size == -2)"
+	 */
+	public void recordMergedFromP2(Path fname) {
+		forget(fname);
+		normal.put(fname, new HgDirstate.Record(0, -2, -1, fname, null));
+	}
+	
 	private HgDirstate.Record forget(Path fname) {
 		HgDirstate.Record r;
 		if ((r = normal.remove(fname)) != null) {
--- a/src/org/tmatesoft/hg/internal/FileUtils.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/internal/FileUtils.java	Thu Aug 15 18:43:50 2013 +0200
@@ -105,7 +105,7 @@
 		fos.flush();
 		fos.close();
 	}
-
+	
 	public void closeQuietly(Closeable stream) {
 		closeQuietly(stream, null);
 	}
@@ -126,4 +126,9 @@
 			}
 		}
 	}
+
+	// nothing special, just a single place with common prefix
+	public File createTempFile() throws IOException {
+		return File.createTempFile("hg4j-", null);
+	}
 }
--- a/src/org/tmatesoft/hg/internal/Internals.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/internal/Internals.java	Thu Aug 15 18:43:50 2013 +0200
@@ -513,6 +513,10 @@
 	public RevlogStream resolveStoreFile(Path path) {
 		return streamProvider.getStoreFile(path, false);
 	}
+	
+	public Transaction.Factory getTransactionFactory() {
+		return new COWTransaction.Factory();
+	}
 
 	// marker method
 	public static IllegalStateException notImplemented() {
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/org/tmatesoft/hg/internal/MergeStateBuilder.java	Thu Aug 15 18:43:50 2013 +0200
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2013 TMate Software Ltd
+ *  
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For information on how to redistribute this software under
+ * the terms of a license other than GNU General Public License
+ * contact TMate Software at support@hg4j.com
+ */
+package org.tmatesoft.hg.internal;
+
+import org.tmatesoft.hg.core.HgIOException;
+import org.tmatesoft.hg.repo.HgMergeState;
+import org.tmatesoft.hg.util.Path;
+
+/**
+ * Constructs merge/state file
+ * 
+ * @see HgMergeState
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class MergeStateBuilder {
+	
+	private final Internals repo;
+
+	public MergeStateBuilder(Internals implRepo) {
+		repo = implRepo;
+	}
+	
+	public void resolved() {
+		throw Internals.notImplemented();
+	}
+
+	public void unresolved(Path file) {
+		throw Internals.notImplemented();
+	}
+
+	public void serialize(Transaction tr) throws HgIOException {
+	}
+}
--- a/src/org/tmatesoft/hg/internal/WorkingDirFileWriter.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/internal/WorkingDirFileWriter.java	Thu Aug 15 18:43:50 2013 +0200
@@ -21,9 +21,12 @@
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.io.InputStream;
 import java.nio.ByteBuffer;
 import java.nio.channels.FileChannel;
 
+import org.tmatesoft.hg.core.HgFileRevision;
+import org.tmatesoft.hg.core.HgIOException;
 import org.tmatesoft.hg.repo.HgDataFile;
 import org.tmatesoft.hg.repo.HgManifest;
 import org.tmatesoft.hg.repo.HgRuntimeException;
@@ -65,45 +68,94 @@
 	 * Executable bit is set if specified and filesystem supports it. 
 	 * @throws HgRuntimeException 
 	 */
-	public void processFile(HgDataFile df, int fileRevIndex, HgManifest.Flags flags) throws IOException, HgRuntimeException {
-		try {
-			prepare(df.getPath());
-			if (flags != HgManifest.Flags.Link) {
-				destChannel = new FileOutputStream(dest).getChannel();
-			} else {
-				linkChannel = new ByteArrayChannel();
-			}
-			df.contentWithFilters(fileRevIndex, this);
-		} catch (CancelledException ex) {
-			hgRepo.getSessionContext().getLog().dump(getClass(), Severity.Error, ex, "Our impl doesn't throw cancellation");
-		} finally {
-			if (flags != HgManifest.Flags.Link) {
-				destChannel.close();
-				destChannel = null;
-				// leave dest in case anyone enquires with #getDestinationFile
+	public void processFile(final HgDataFile df, final int fileRevIndex, HgManifest.Flags flags) throws HgIOException, HgRuntimeException {
+		processFile(df.getPath(), new Fetch() {
+			public void readInto(ByteChannel ch) {
+				try {
+					df.contentWithFilters(fileRevIndex, ch);
+				} catch (CancelledException ex) {
+					handleUnexpectedCancel(ex);
+				}
 			}
-		}
-		if (linkChannel != null && symlinkCap) {
-			assert flags == HgManifest.Flags.Link;
-			fileFlagsHelper.createSymlink(dest.getParentFile(), dest.getName(), linkChannel.toArray());
-		} else if (flags == HgManifest.Flags.Exec && execCap) {
-			fileFlagsHelper.setExecutableBit(dest.getParentFile(), dest.getName());
-		}
-		// Although HgWCStatusCollector treats 644 (`hg manifest -v`) and 664 (my fs) the same, it's better
-		// to detect actual flags here
-		fmode = flags.fsMode(); // default to one from manifest
-		if (fileFlagsHelper != null) {
-			// if neither execBit nor link is supported by fs, it's unlikely file mode is supported, too.
+		}, flags);
+	}
+	
+	public void processFile(final HgFileRevision fr) throws HgIOException, HgRuntimeException {
+		processFile(fr.getPath(), new Fetch() {
+			
+			public void readInto(ByteChannel ch) throws IOException, HgRuntimeException {
+				try {
+					fr.putContentTo(ch);
+				} catch (CancelledException ex) {
+					handleUnexpectedCancel(ex);
+				}
+			}
+		}, fr.getFileFlags());
+	}
+	
+	/**
+	 * Closes supplied content stream 
+	 */
+	public void processFile(Path fname, final InputStream content, HgManifest.Flags flags) throws HgIOException, HgRuntimeException {
+		processFile(fname, new Fetch() {
+			
+			public void readInto(ByteChannel ch) throws IOException, HgRuntimeException {
+				try {
+					 ByteBuffer bb = ByteBuffer.wrap(new byte[8*1024]);
+					 int r;
+					 while ((r = content.read(bb.array())) != -1) {
+						 bb.position(0).limit(r);
+						 for (int wrote = 0; wrote < r; ) {
+							 r -= wrote; 
+							 wrote = ch.write(bb);
+							 assert bb.remaining() == r - wrote;
+						 }
+					 }
+				} catch (CancelledException ex) {
+					handleUnexpectedCancel(ex);
+				}
+			}
+		}, flags);
+	}
+	
+	private interface Fetch {
+		void readInto(ByteChannel ch) throws IOException, HgRuntimeException;
+	}
+
+	private void processFile(Path fname, Fetch fetch, HgManifest.Flags flags) throws HgIOException, HgRuntimeException {
+		try {
+			byte[] symlinkContent = null;
 			try {
-				fmode = fileFlagsHelper.getFileMode(dest, fmode);
-			} catch (IOException ex) {
-				// Warn, we've got default value and can live with it
-				hgRepo.getSessionContext().getLog().dump(getClass(), Warn, ex, "Failed get file access rights");
+				prepare(fname, flags);
+				fetch.readInto(this);
+			} finally {
+				symlinkContent = close(fname, flags);
 			}
+			if (flags == HgManifest.Flags.Link && symlinkCap) {
+				assert symlinkContent != null;
+				fileFlagsHelper.createSymlink(dest.getParentFile(), dest.getName(), symlinkContent);
+			} else if (flags == HgManifest.Flags.Exec && execCap) {
+				fileFlagsHelper.setExecutableBit(dest.getParentFile(), dest.getName());
+			}
+			// Although HgWCStatusCollector treats 644 (`hg manifest -v`) and 664 (my fs) the same, it's better
+			// to detect actual flags here
+			fmode = flags.fsMode(); // default to one from manifest
+			if (fileFlagsHelper != null) {
+				// if neither execBit nor link is supported by fs, it's unlikely file mode is supported, too.
+				try {
+					fmode = fileFlagsHelper.getFileMode(dest, fmode);
+				} catch (IOException ex) {
+					// Warn, we've got default value and can live with it
+					hgRepo.getSessionContext().getLog().dump(getClass(), Warn, ex, "Failed get file access rights");
+				}
+			}
+		} catch (IOException ex) {
+			String msg = String.format("Failed to write file %s to the working directory", fname);
+			throw new HgIOException(msg, ex, dest);
 		}
 	}
 
-	public void prepare(Path fname) throws IOException {
+	private void prepare(Path fname, HgManifest.Flags flags) throws IOException {
 		String fpath = fname.toString();
 		dest = new File(hgRepo.getRepo().getWorkingDir(), fpath);
 		if (fpath.indexOf('/') != -1) {
@@ -113,6 +165,25 @@
 		linkChannel = null;
 		totalBytesWritten = 0;
 		fmode = 0;
+		if (flags != HgManifest.Flags.Link) {
+			destChannel = new FileOutputStream(dest).getChannel();
+		} else {
+			linkChannel = new ByteArrayChannel();
+		}
+	}
+	
+	private byte[] close(Path fname, HgManifest.Flags flags) throws IOException {
+		if (flags != HgManifest.Flags.Link) {
+			destChannel.close();
+			destChannel = null;
+			// leave dest in case anyone enquires with #getDestinationFile
+		}
+		if (linkChannel != null) {
+			final byte[] rv = linkChannel.toArray();
+			linkChannel = null;
+			return rv;
+		}
+		return null;
 	}
 
 	public int write(ByteBuffer buffer) throws IOException, CancelledException {
@@ -144,4 +215,8 @@
 	public int mtime() {
 		return (int) (dest.lastModified() / 1000);
 	}
+
+	private void handleUnexpectedCancel(CancelledException ex) {
+		hgRepo.getSessionContext().getLog().dump(WorkingDirFileWriter.class, Severity.Error, ex, "Our impl doesn't throw cancellation");
+	}
 }
--- a/src/org/tmatesoft/hg/repo/HgMergeState.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/repo/HgMergeState.java	Thu Aug 15 18:43:50 2013 +0200
@@ -218,7 +218,7 @@
 
 	/**
 	 * List of conflicts as recorded in the merge state information file. 
-	 * Note, this information is valid unless {@link #isStale()} is <code>true</code>.
+	 * Note, this information is not valid unless {@link #isStale()} is <code>true</code>.
 	 * 
 	 * @return non-<code>null</code> list with both resolved and unresolved conflicts.
 	 */
--- a/src/org/tmatesoft/hg/util/Path.java	Wed Aug 14 20:07:26 2013 +0200
+++ b/src/org/tmatesoft/hg/util/Path.java	Thu Aug 15 18:43:50 2013 +0200
@@ -214,6 +214,7 @@
 	public static class SimpleSource implements Source {
 		private final PathRewrite normalizer;
 		private final Convertor<Path> convertor;
+		private final Path.Source delegate;
 
 		public SimpleSource() {
 			this(new PathRewrite.Empty(), null);
@@ -224,12 +225,30 @@
 		}
 
 		public SimpleSource(PathRewrite pathRewrite, Convertor<Path> pathConvertor) {
+			assert pathRewrite != null;
 			normalizer = pathRewrite;
 			convertor = pathConvertor;
+			delegate = null;
+		}
+
+		public SimpleSource(Path.Source actual, Convertor<Path> pathConvertor) {
+			assert actual != null;
+			normalizer = null;
+			delegate = actual;
+			convertor = pathConvertor;
 		}
 
 		public Path path(CharSequence p) {
-			Path rv = Path.create(normalizer.rewrite(p));
+			// in fact, it's nicer to have sequence of sources, and a bunch of small
+			// Source implementations each responsible for specific aspect, like Convertor
+			// or delegation to another Source. However, these classes are just too small 
+			// to justify their existence
+			Path rv;
+			if (delegate != null) {
+				rv = delegate.path(p);
+			} else {
+				rv = Path.create(normalizer.rewrite(p));
+			}
 			if (convertor != null) {
 				return convertor.mangle(rv);
 			}