--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/com/tmate/hgkit/console/Incoming.java	Wed Jan 12 00:30:55 2011 +0100
@@ -0,0 +1,184 @@
+/*
+ * Copyright (c) 2011 Artem Tikhomirov 
+ */
+package com.tmate.hgkit.console;
+
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.LinkedHashSet;
+import java.util.LinkedList;
+import java.util.List;
+
+import com.tmate.hgkit.fs.RepositoryLookup;
+import com.tmate.hgkit.ll.HgRepository;
+import com.tmate.hgkit.ll.Nodeid;
+import com.tmate.hgkit.ll.Revlog;
+
+/**
+ *
+ * @author artem
+ */
+public class Incoming {
+
+	public static void main(String[] args) throws Exception {
+		RepositoryLookup repoLookup = new RepositoryLookup();
+		RepositoryLookup.Options cmdLineOpts = RepositoryLookup.Options.parse(args);
+		HgRepository hgRepo = repoLookup.detect(cmdLineOpts);
+		if (hgRepo.isInvalid()) {
+			System.err.printf("Can't find repository in: %s\n", hgRepo.getLocation());
+			return;
+		}
+		// in fact, all we need from changelog is set of all nodeids. However, since ParentWalker reuses same Nodeids, it's not too expensive
+		// to reuse it here, XXX although later this may need to be refactored
+		final Revlog.ParentWalker pw = hgRepo.getChangelog().new ParentWalker();
+		pw.init();
+		//
+		HashSet<Nodeid> base = new HashSet<Nodeid>();
+		HashSet<Nodeid> unknownRemoteHeads = new HashSet<Nodeid>();
+		// imagine empty repository - any nodeid from remote heads would be unknown
+		unknownRemoteHeads.add(Nodeid.fromAscii("382cfe9463db0484a14136e4b38407419525f0c0".getBytes(), 0, 40));
+		//
+		LinkedList<RemoteBranch> remoteBranches = new LinkedList<RemoteBranch>();
+		remoteBranches(unknownRemoteHeads, remoteBranches);
+		//
+		HashSet<Nodeid> visited = new HashSet<Nodeid>();
+		HashSet<RemoteBranch> processed = new HashSet<RemoteBranch>();
+		LinkedList<Nodeid[]> toScan = new LinkedList<Nodeid[]>();
+		LinkedHashSet<Nodeid> toFetch = new LinkedHashSet<Nodeid>();
+		// next one seems to track heads we've asked (or plan to ask) remote.branches for
+		HashSet<Nodeid> unknownHeads /*req*/ = new HashSet<Nodeid>(unknownRemoteHeads);
+		while (!remoteBranches.isEmpty()) {
+			LinkedList<Nodeid> toQueryRemote = new LinkedList<Nodeid>();
+			while (!remoteBranches.isEmpty()) {
+				RemoteBranch next = remoteBranches.removeFirst();
+				if (visited.contains(next.head) || processed.contains(next)) {
+					continue;
+				}
+				if (Nodeid.NULL.equals(next.head)) {
+					// it's discovery.py that expects next.head to be nullid here, I can't imagine how this may happen, hence this exception
+					throw new IllegalStateException("I wonder if null if may ever get here with remote branches");
+				} else if (pw.knownNode(next.root)) {
+					// root of the remote change is known locally, analyze to find exact missing changesets
+					toScan.addLast(new Nodeid[] { next.head, next.root });
+					processed.add(next);
+				} else {
+					if (!visited.contains(next.root) && !toFetch.contains(next.root)) {
+						// if parents are locally known, this is new branch (sequence of changes) (sequence sprang out of known parents) 
+						if ((next.p1 == null || pw.knownNode(next.p1)) && (next.p2 == null || pw.knownNode(next.p2))) {
+							toFetch.add(next.root);
+						}
+						// XXX perhaps, may combine this parent processing below (I don't understand what this code is exactly about)
+						if (pw.knownNode(next.p1)) {
+							base.add(next.p1);
+						}
+						if (pw.knownNode(next.p2)) {
+							base.add(next.p2);
+						}
+					}
+					if (next.p1 != null && !pw.knownNode(next.p1) && !unknownHeads.contains(next.p1)) {
+						toQueryRemote.add(next.p1);
+						unknownHeads.add(next.p1);
+					}
+					if (next.p2 != null && !pw.knownNode(next.p2) && !unknownHeads.contains(next.p2)) {
+						toQueryRemote.add(next.p2);
+						unknownHeads.add(next.p2);
+					}
+				}
+				visited.add(next.head);
+			}
+			if (!toQueryRemote.isEmpty()) {
+				// discovery.py in fact does this in batches of 10 revisions a time.
+				// however, this slicing may be done in remoteBranches call instead (if needed)
+				remoteBranches(toQueryRemote, remoteBranches);
+			}
+		}
+		while (!toScan.isEmpty()) {
+			Nodeid[] head_root = toScan.removeFirst();
+			List<Nodeid> nodesBetween = remoteBetween(head_root[0], head_root[1], new LinkedList<Nodeid>());
+			nodesBetween.add(head_root[1]);
+			int x = 1;
+			Nodeid p = head_root[0];
+			for (Nodeid i : nodesBetween) {
+				System.out.println("narrowing " + x + ":" + nodesBetween.size() + " " + i.shortNotation());
+				if (pw.knownNode(i)) {
+					if (x <= 2) {
+						toFetch.add(p);
+						base.add(i);
+					} else {
+						// XXX original discovery.py collects new elements to scan separately
+						// likely to "batch" calls to server
+						System.out.println("narrowed branch search to " + p.shortNotation() + ":" + i.shortNotation());
+						toScan.addLast(new Nodeid[] { p, i });
+					}
+					break;
+				}
+				x = x << 1;
+				p = i;
+			}
+		}
+		for (Nodeid n : toFetch) {
+			if (pw.knownNode(n)) {
+				System.out.println("Erroneous to fetch:" + n);
+			} else {
+				System.out.println(n);
+			}
+		}
+	}
+
+	static final class RemoteBranch {
+		public Nodeid head, root, p1, p2;
+
+		@Override
+		public boolean equals(Object obj) {
+			if (this == obj) {
+				return true;
+			}
+			if (false == obj instanceof RemoteBranch) {
+				return false;
+			}
+			RemoteBranch o = (RemoteBranch) obj;
+			return head.equals(o.head) && root.equals(o.root) && (p1 == null && o.p1 == null || p1.equals(o.p1)) && (p2 == null && o.p2 == null || p2.equals(o.p2));
+		}
+	}
+
+	private static void remoteBranches(Collection<Nodeid> unknownRemoteHeads, List<RemoteBranch> remoteBranches) {
+		// discovery.findcommonincoming:
+		// unknown = remote.branches(remote.heads); 
+		// sent: cmd=branches&roots=d6d2a630f4a6d670c90a5ca909150f2b426ec88f+
+		// received: d6d2a630f4a6d670c90a5ca909150f2b426ec88f dbd663faec1f0175619cf7668bddc6350548b8d6 0000000000000000000000000000000000000000 0000000000000000000000000000000000000000
+		// head, root, first parent, second parent
+		//
+		// TODO implement this with remote access
+		//
+		RemoteBranch rb = new RemoteBranch();
+		rb.head = unknownRemoteHeads.iterator().next();
+		rb.root = Nodeid.fromAscii("dbd663faec1f0175619cf7668bddc6350548b8d6".getBytes(), 0, 40);
+		remoteBranches.add(rb);
+	}
+
+	private static List<Nodeid> remoteBetween(Nodeid nodeid1, Nodeid nodeid2, List<Nodeid> list) {
+		// sent: cmd=between&pairs=d6d2a630f4a6d670c90a5ca909150f2b426ec88f-dbd663faec1f0175619cf7668bddc6350548b8d6
+		// received: a78c980749e3ccebb47138b547e9b644a22797a9 286d221f6c28cbfce25ea314e1f46a23b7f979d3 fc265ddeab262ff5c34b4cf4e2522d8d41f1f05b a3576694a4d1edaa681cab15b89d6b556b02aff4
+		// 1st, 2nd, fourth and eights of total 8 changes between rev9 and rev0
+		//
+		//
+		//           a78c980749e3ccebb47138b547e9b644a22797a9 286d221f6c28cbfce25ea314e1f46a23b7f979d3 fc265ddeab262ff5c34b4cf4e2522d8d41f1f05b a3576694a4d1edaa681cab15b89d6b556b02aff4
+		//d6d2a630f4a6d670c90a5ca909150f2b426ec88f a78c980749e3ccebb47138b547e9b644a22797a9 5abe5af181bd6a6d3e94c378376c901f0f80da50 08db726a0fb7914ac9d27ba26dc8bbf6385a0554
+
+		// TODO implement with remote access
+		String response = null;
+		if (nodeid1.equals(Nodeid.fromAscii("382cfe9463db0484a14136e4b38407419525f0c0".getBytes(), 0, 40)) && nodeid2.equals(Nodeid.fromAscii("dbd663faec1f0175619cf7668bddc6350548b8d6".getBytes(), 0, 40))) {
+			response = "d6d2a630f4a6d670c90a5ca909150f2b426ec88f a78c980749e3ccebb47138b547e9b644a22797a9 5abe5af181bd6a6d3e94c378376c901f0f80da50 08db726a0fb7914ac9d27ba26dc8bbf6385a0554";
+		} else if (nodeid1.equals(Nodeid.fromAscii("a78c980749e3ccebb47138b547e9b644a22797a9".getBytes(), 0, 40)) && nodeid2.equals(Nodeid.fromAscii("5abe5af181bd6a6d3e94c378376c901f0f80da50".getBytes(), 0, 40))) {
+			response = "286d221f6c28cbfce25ea314e1f46a23b7f979d3";
+		}
+		if (response == null) {
+			throw HgRepository.notImplemented();
+		}
+		for (String s : response.split(" ")) {
+			list.add(Nodeid.fromAscii(s.getBytes(), 0, 40));
+		}
+		return list;
+	}
+
+}