Merge branch 'maint' into tj/imap-send-remove-unused

* maint: (18123 commits)
  documentation fix: git difftool uses diff tools, not merge tools.
  Git 1.7.7.4
  Makefile: add missing header file dependencies
  notes merge: eliminate OUTPUT macro
  mailmap: xcalloc mailmap_info
  name-rev --all: do not even attempt to describe non-commit object
  Git 1.7.7.3
  docs: Update install-doc-quick
  docs: don't mention --quiet or --exit-code in git-log(1)
  Git 1.7.7.2
  t7511: avoid use of reserved filename on Windows.
  clone: Quote user supplied path in a single quote pair
  read-cache.c: fix index memory allocation
  make the sample pre-commit hook script reject names with newlines, too
  Reindent closing bracket using tab instead of spaces
  Git 1.7.7.1
  RelNotes/1.7.7.1: setgid bit patch is about fixing "git init" via Makefile setting
  gitweb: fix regression when filtering out forks
  Almost ready for 1.7.7.1
  pack-objects: don't traverse objects unnecessarily
  ...

Conflicts:
	imap-send.c

1 files changed, 1979 insertions, 336 deletions

diff --git a/revision.c b/revision.c
index c8d93ff106..3d2deedaf8 100644
--- a/revision.c
+++ b/revision.c
@@ -6,10 +6,19 @@
 #include "diff.h"
 #include "refs.h"
 #include "revision.h"
+#include "graph.h"
+#include "grep.h"
+#include "reflog-walk.h"
+#include "patch-ids.h"
+#include "decorate.h"
+#include "log-tree.h"
+#include "string-list.h"
 
-static char *path_name(struct name_path *path, const char *name)
+volatile show_early_output_fn_t show_early_output;
+
+char *path_name(const struct name_path *path, const char *name)
 {
-	struct name_path *p;
+	const struct name_path *p;
 	char *n, *m;
 	int nlen = strlen(name);
 	int len = nlen + 1;
@@ -31,21 +40,18 @@ static char *path_name(struct name_path *path, const char *name)
 	return n;
 }
 
-struct object_list **add_object(struct object *obj,
-				       struct object_list **p,
-				       struct name_path *path,
-				       const char *name)
+void add_object(struct object *obj,
+		struct object_array *p,
+		struct name_path *path,
+		const char *name)
 {
-	struct object_list *entry = xmalloc(sizeof(*entry));
-	entry->item = obj;
-	entry->next = *p;
-	entry->name = path_name(path, name);
-	*p = entry;
-	return &entry->next;
+	add_object_array(obj, path_name(path, name), p);
 }
 
 static void mark_blob_uninteresting(struct blob *blob)
 {
+	if (!blob)
+		return;
 	if (blob->object.flags & UNINTERESTING)
 		return;
 	blob->object.flags |= UNINTERESTING;
@@ -53,9 +59,12 @@ static void mark_blob_uninteresting(struct blob *blob)
 
 void mark_tree_uninteresting(struct tree *tree)
 {
+	struct tree_desc desc;
+	struct name_entry entry;
 	struct object *obj = &tree->object;
-	struct tree_entry_list *entry;
 
+	if (!tree)
+		return;
 	if (obj->flags & UNINTERESTING)
 		return;
 	obj->flags |= UNINTERESTING;
@@ -63,17 +72,28 @@ void mark_tree_uninteresting(struct tree *tree)
 		return;
 	if (parse_tree(tree) < 0)
 		die("bad tree %s", sha1_to_hex(obj->sha1));
-	entry = tree->entries;
-	tree->entries = NULL;
-	while (entry) {
-		struct tree_entry_list *next = entry->next;
-		if (entry->directory)
-			mark_tree_uninteresting(entry->item.tree);
-		else
-			mark_blob_uninteresting(entry->item.blob);
-		free(entry);
-		entry = next;
+
+	init_tree_desc(&desc, tree->buffer, tree->size);
+	while (tree_entry(&desc, &entry)) {
+		switch (object_type(entry.mode)) {
+		case OBJ_TREE:
+			mark_tree_uninteresting(lookup_tree(entry.sha1));
+			break;
+		case OBJ_BLOB:
+			mark_blob_uninteresting(lookup_blob(entry.sha1));
+			break;
+		default:
+			/* Subproject commit - not in this repository */
+			break;
+		}
 	}
+
+	/*
+	 * We don't care about the tree any more
+	 * after it has been marked uninteresting.
+	 */
+	free(tree->buffer);
+	tree->buffer = NULL;
 }
 
 void mark_parents_uninteresting(struct commit *commit)
@@ -111,53 +131,104 @@ void mark_parents_uninteresting(struct commit *commit)
 	}
 }
 
-static void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
+static void add_pending_object_with_mode(struct rev_info *revs, struct object *obj, const char *name, unsigned mode)
+{
+	if (!obj)
+		return;
+	if (revs->no_walk && (obj->flags & UNINTERESTING))
+		revs->no_walk = 0;
+	if (revs->reflog_info && obj->type == OBJ_COMMIT) {
+		struct strbuf buf = STRBUF_INIT;
+		int len = interpret_branch_name(name, &buf);
+		int st;
+
+		if (0 < len && name[len] && buf.len)
+			strbuf_addstr(&buf, name + len);
+		st = add_reflog_for_walk(revs->reflog_info,
+					 (struct commit *)obj,
+					 buf.buf[0] ? buf.buf: name);
+		strbuf_release(&buf);
+		if (st)
+			return;
+	}
+	add_object_array_with_mode(obj, name, &revs->pending, mode);
+}
+
+void add_pending_object(struct rev_info *revs, struct object *obj, const char *name)
 {
-	add_object(obj, &revs->pending_objects, NULL, name);
+	add_pending_object_with_mode(revs, obj, name, S_IFINVALID);
+}
+
+void add_head_to_pending(struct rev_info *revs)
+{
+	unsigned char sha1[20];
+	struct object *obj;
+	if (get_sha1("HEAD", sha1))
+		return;
+	obj = parse_object(sha1);
+	if (!obj)
+		return;
+	add_pending_object(revs, obj, "HEAD");
 }
 
-static struct commit *get_commit_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
+static struct object *get_reference(struct rev_info *revs, const char *name, const unsigned char *sha1, unsigned int flags)
 {
 	struct object *object;
 
 	object = parse_object(sha1);
-	if (!object)
+	if (!object) {
+		if (revs->ignore_missing)
+			return object;
 		die("bad object %s", name);
+	}
+	object->flags |= flags;
+	return object;
+}
+
+static struct commit *handle_commit(struct rev_info *revs, struct object *object, const char *name)
+{
+	unsigned long flags = object->flags;
 
 	/*
 	 * Tag object? Look what it points to..
 	 */
-	while (object->type == tag_type) {
+	while (object->type == OBJ_TAG) {
 		struct tag *tag = (struct tag *) object;
-		object->flags |= flags;
-		if (revs->tag_objects && !(object->flags & UNINTERESTING))
+		if (revs->tag_objects && !(flags & UNINTERESTING))
 			add_pending_object(revs, object, tag->tag);
+		if (!tag->tagged)
+			die("bad tag");
 		object = parse_object(tag->tagged->sha1);
-		if (!object)
+		if (!object) {
+			if (flags & UNINTERESTING)
+				return NULL;
 			die("bad object %s", sha1_to_hex(tag->tagged->sha1));
+		}
 	}
 
 	/*
 	 * Commit object? Just return it, we'll do all the complex
 	 * reachability crud.
 	 */
-	if (object->type == commit_type) {
+	if (object->type == OBJ_COMMIT) {
 		struct commit *commit = (struct commit *)object;
-		object->flags |= flags;
 		if (parse_commit(commit) < 0)
 			die("unable to parse commit %s", name);
 		if (flags & UNINTERESTING) {
+			commit->object.flags |= UNINTERESTING;
 			mark_parents_uninteresting(commit);
 			revs->limited = 1;
 		}
+		if (revs->show_source && !commit->util)
+			commit->util = (void *) name;
 		return commit;
 	}
 
 	/*
-	 * Tree object? Either mark it uniniteresting, or add it
+	 * Tree object? Either mark it uninteresting, or add it
 	 * to the list of objects to look at later..
 	 */
-	if (object->type == tree_type) {
+	if (object->type == OBJ_TREE) {
 		struct tree *tree = (struct tree *)object;
 		if (!revs->tree_objects)
 			return NULL;
@@ -172,7 +243,7 @@ static struct commit *get_commit_reference(struct rev_info *revs, const char *na
 	/*
 	 * Blob object? You know the drill by now..
 	 */
-	if (object->type == blob_type) {
+	if (object->type == OBJ_BLOB) {
 		struct blob *blob = (struct blob *)object;
 		if (!revs->blob_objects)
 			return NULL;
@@ -199,108 +270,140 @@ static int everybody_uninteresting(struct commit_list *orig)
 	return 1;
 }
 
-#define TREE_SAME	0
-#define TREE_NEW	1
-#define TREE_DIFFERENT	2
-static int tree_difference = TREE_SAME;
+/*
+ * The goal is to get REV_TREE_NEW as the result only if the
+ * diff consists of all '+' (and no other changes), REV_TREE_OLD
+ * if the whole diff is removal of old data, and otherwise
+ * REV_TREE_DIFFERENT (of course if the trees are the same we
+ * want REV_TREE_SAME).
+ * That means that once we get to REV_TREE_DIFFERENT, we do not
+ * have to look any further.
+ */
+static int tree_difference = REV_TREE_SAME;
 
 static void file_add_remove(struct diff_options *options,
 		    int addremove, unsigned mode,
 		    const unsigned char *sha1,
-		    const char *base, const char *path)
+		    const char *fullpath, unsigned dirty_submodule)
 {
-	int diff = TREE_DIFFERENT;
+	int diff = addremove == '+' ? REV_TREE_NEW : REV_TREE_OLD;
 
-	/*
-	 * Is it an add of a new file? It means that
-	 * the old tree didn't have it at all, so we
-	 * will turn "TREE_SAME" -> "TREE_NEW", but
-	 * leave any "TREE_DIFFERENT" alone (and if
-	 * it already was "TREE_NEW", we'll keep it
-	 * "TREE_NEW" of course).
-	 */
-	if (addremove == '+') {
-		diff = tree_difference;
-		if (diff != TREE_SAME)
-			return;
-		diff = TREE_NEW;
-	}
-	tree_difference = diff;
+	tree_difference |= diff;
+	if (tree_difference == REV_TREE_DIFFERENT)
+		DIFF_OPT_SET(options, HAS_CHANGES);
 }
 
 static void file_change(struct diff_options *options,
 		 unsigned old_mode, unsigned new_mode,
 		 const unsigned char *old_sha1,
 		 const unsigned char *new_sha1,
-		 const char *base, const char *path)
+		 const char *fullpath,
+		 unsigned old_dirty_submodule, unsigned new_dirty_submodule)
 {
-	tree_difference = TREE_DIFFERENT;
+	tree_difference = REV_TREE_DIFFERENT;
+	DIFF_OPT_SET(options, HAS_CHANGES);
 }
 
-static struct diff_options diff_opt = {
-	.recursive = 1,
-	.add_remove = file_add_remove,
-	.change = file_change,
-};
-
-static int compare_tree(struct tree *t1, struct tree *t2)
+static int rev_compare_tree(struct rev_info *revs, struct commit *parent, struct commit *commit)
 {
+	struct tree *t1 = parent->tree;
+	struct tree *t2 = commit->tree;
+
 	if (!t1)
-		return TREE_NEW;
+		return REV_TREE_NEW;
 	if (!t2)
-		return TREE_DIFFERENT;
-	tree_difference = TREE_SAME;
-	if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "", &diff_opt) < 0)
-		return TREE_DIFFERENT;
+		return REV_TREE_OLD;
+
+	if (revs->simplify_by_decoration) {
+		/*
+		 * If we are simplifying by decoration, then the commit
+		 * is worth showing if it has a tag pointing at it.
+		 */
+		if (lookup_decoration(&name_decoration, &commit->object))
+			return REV_TREE_DIFFERENT;
+		/*
+		 * A commit that is not pointed by a tag is uninteresting
+		 * if we are not limited by path.  This means that you will
+		 * see the usual "commits that touch the paths" plus any
+		 * tagged commit by specifying both --simplify-by-decoration
+		 * and pathspec.
+		 */
+		if (!revs->prune_data.nr)
+			return REV_TREE_SAME;
+	}
+
+	tree_difference = REV_TREE_SAME;
+	DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
+	if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
+			   &revs->pruning) < 0)
+		return REV_TREE_DIFFERENT;
 	return tree_difference;
 }
 
-static int same_tree_as_empty(struct tree *t1)
+static int rev_same_tree_as_empty(struct rev_info *revs, struct commit *commit)
 {
 	int retval;
 	void *tree;
+	unsigned long size;
 	struct tree_desc empty, real;
+	struct tree *t1 = commit->tree;
 
 	if (!t1)
 		return 0;
 
-	tree = read_object_with_reference(t1->object.sha1, "tree", &real.size, NULL);
+	tree = read_object_with_reference(t1->object.sha1, tree_type, &size, NULL);
 	if (!tree)
 		return 0;
-	real.buf = tree;
-
-	empty.buf = "";
-	empty.size = 0;
+	init_tree_desc(&real, tree, size);
+	init_tree_desc(&empty, "", 0);
 
-	tree_difference = 0;
-	retval = diff_tree(&empty, &real, "", &diff_opt);
+	tree_difference = REV_TREE_SAME;
+	DIFF_OPT_CLR(&revs->pruning, HAS_CHANGES);
+	retval = diff_tree(&empty, &real, "", &revs->pruning);
 	free(tree);
 
-	return retval >= 0 && !tree_difference;
+	return retval >= 0 && (tree_difference == REV_TREE_SAME);
 }
 
 static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 {
 	struct commit_list **pp, *parent;
-	int tree_changed = 0;
+	int tree_changed = 0, tree_same = 0;
+
+	/*
+	 * If we don't do pruning, everything is interesting
+	 */
+	if (!revs->prune)
+		return;
 
 	if (!commit->tree)
 		return;
 
 	if (!commit->parents) {
-		if (!same_tree_as_empty(commit->tree))
-			commit->object.flags |= TREECHANGE;
+		if (rev_same_tree_as_empty(revs, commit))
+			commit->object.flags |= TREESAME;
 		return;
 	}
 
+	/*
+	 * Normal non-merge commit? If we don't want to make the
+	 * history dense, we consider it always to be a change..
+	 */
+	if (!revs->dense && !commit->parents->next)
+		return;
+
 	pp = &commit->parents;
 	while ((parent = *pp) != NULL) {
 		struct commit *p = parent->item;
 
-		parse_commit(p);
-		switch (compare_tree(p->tree, commit->tree)) {
-		case TREE_SAME:
-			if (p->object.flags & UNINTERESTING) {
+		if (parse_commit(p) < 0)
+			die("cannot simplify commit %s (because of %s)",
+			    sha1_to_hex(commit->object.sha1),
+			    sha1_to_hex(p->object.sha1));
+		switch (rev_compare_tree(revs, p, commit)) {
+		case REV_TREE_SAME:
+			tree_same = 1;
+			if (!revs->simplify_history || (p->object.flags & UNINTERESTING)) {
 				/* Even if a merge with an uninteresting
 				 * side branch brought the entire change
 				 * we are interested in, we do not want
@@ -312,28 +415,64 @@ static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
 			}
 			parent->next = NULL;
 			commit->parents = parent;
+			commit->object.flags |= TREESAME;
 			return;
 
-		case TREE_NEW:
-			if (revs->remove_empty_trees && same_tree_as_empty(p->tree)) {
-				*pp = parent->next;
-				continue;
+		case REV_TREE_NEW:
+			if (revs->remove_empty_trees &&
+			    rev_same_tree_as_empty(revs, p)) {
+				/* We are adding all the specified
+				 * paths from this parent, so the
+				 * history beyond this parent is not
+				 * interesting.  Remove its parents
+				 * (they are grandparents for us).
+				 * IOW, we pretend this parent is a
+				 * "root" commit.
+				 */
+				if (parse_commit(p) < 0)
+					die("cannot simplify commit %s (invalid %s)",
+					    sha1_to_hex(commit->object.sha1),
+					    sha1_to_hex(p->object.sha1));
+				p->parents = NULL;
 			}
 		/* fallthrough */
-		case TREE_DIFFERENT:
+		case REV_TREE_OLD:
+		case REV_TREE_DIFFERENT:
 			tree_changed = 1;
 			pp = &parent->next;
 			continue;
 		}
 		die("bad tree compare for commit %s", sha1_to_hex(commit->object.sha1));
 	}
-	if (tree_changed)
-		commit->object.flags |= TREECHANGE;
+	if (tree_changed && !tree_same)
+		return;
+	commit->object.flags |= TREESAME;
+}
+
+static void commit_list_insert_by_date_cached(struct commit *p, struct commit_list **head,
+		    struct commit_list *cached_base, struct commit_list **cache)
+{
+	struct commit_list *new_entry;
+
+	if (cached_base && p->date < cached_base->item->date)
+		new_entry = commit_list_insert_by_date(p, &cached_base->next);
+	else
+		new_entry = commit_list_insert_by_date(p, head);
+
+	if (cache && (!*cache || p->date < (*cache)->item->date))
+		*cache = new_entry;
 }
 
-static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
+static int add_parents_to_list(struct rev_info *revs, struct commit *commit,
+		    struct commit_list **list, struct commit_list **cache_ptr)
 {
 	struct commit_list *parent = commit->parents;
+	unsigned left_flag;
+	struct commit_list *cached_base = cache_ptr ? *cache_ptr : NULL;
+
+	if (commit->object.flags & ADDED)
+		return 0;
+	commit->object.flags |= ADDED;
 
 	/*
 	 * If the commit is uninteresting, don't try to
@@ -351,16 +490,18 @@ static void add_parents_to_list(struct rev_info *revs, struct commit *commit, st
 		while (parent) {
 			struct commit *p = parent->item;
 			parent = parent->next;
-			parse_commit(p);
-			p->object.flags |= UNINTERESTING;
+			if (p)
+				p->object.flags |= UNINTERESTING;
+			if (parse_commit(p) < 0)
+				continue;
 			if (p->parents)
 				mark_parents_uninteresting(p);
 			if (p->object.flags & SEEN)
 				continue;
 			p->object.flags |= SEEN;
-			insert_by_date(p, list);
+			commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
 		}
-		return;
+		return 0;
 	}
 
 	/*
@@ -368,81 +509,1115 @@ static void add_parents_to_list(struct rev_info *revs, struct commit *commit, st
 	 * simplify the commit history and find the parent
 	 * that has no differences in the path set if one exists.
 	 */
-	if (revs->paths)
-		try_to_simplify_commit(revs, commit);
+	try_to_simplify_commit(revs, commit);
 
-	parent = commit->parents;
-	while (parent) {
+	if (revs->no_walk)
+		return 0;
+
+	left_flag = (commit->object.flags & SYMMETRIC_LEFT);
+
+	for (parent = commit->parents; parent; parent = parent->next) {
 		struct commit *p = parent->item;
 
-		parent = parent->next;
+		if (parse_commit(p) < 0)
+			return -1;
+		if (revs->show_source && !p->util)
+			p->util = commit->util;
+		p->object.flags |= left_flag;
+		if (!(p->object.flags & SEEN)) {
+			p->object.flags |= SEEN;
+			commit_list_insert_by_date_cached(p, list, cached_base, cache_ptr);
+		}
+		if (revs->first_parent_only)
+			break;
+	}
+	return 0;
+}
+
+static void cherry_pick_list(struct commit_list *list, struct rev_info *revs)
+{
+	struct commit_list *p;
+	int left_count = 0, right_count = 0;
+	int left_first;
+	struct patch_ids ids;
+	unsigned cherry_flag;
+
+	/* First count the commits on the left and on the right */
+	for (p = list; p; p = p->next) {
+		struct commit *commit = p->item;
+		unsigned flags = commit->object.flags;
+		if (flags & BOUNDARY)
+			;
+		else if (flags & SYMMETRIC_LEFT)
+			left_count++;
+		else
+			right_count++;
+	}
+
+	if (!left_count || !right_count)
+		return;
+
+	left_first = left_count < right_count;
+	init_patch_ids(&ids);
+	ids.diffopts.pathspec = revs->diffopt.pathspec;
+
+	/* Compute patch-ids for one side */
+	for (p = list; p; p = p->next) {
+		struct commit *commit = p->item;
+		unsigned flags = commit->object.flags;
+
+		if (flags & BOUNDARY)
+			continue;
+		/*
+		 * If we have fewer left, left_first is set and we omit
+		 * commits on the right branch in this loop.  If we have
+		 * fewer right, we skip the left ones.
+		 */
+		if (left_first != !!(flags & SYMMETRIC_LEFT))
+			continue;
+		commit->util = add_commit_patch_id(commit, &ids);
+	}
 
-		parse_commit(p);
-		if (p->object.flags & SEEN)
+	/* either cherry_mark or cherry_pick are true */
+	cherry_flag = revs->cherry_mark ? PATCHSAME : SHOWN;
+
+	/* Check the other side */
+	for (p = list; p; p = p->next) {
+		struct commit *commit = p->item;
+		struct patch_id *id;
+		unsigned flags = commit->object.flags;
+
+		if (flags & BOUNDARY)
+			continue;
+		/*
+		 * If we have fewer left, left_first is set and we omit
+		 * commits on the left branch in this loop.
+		 */
+		if (left_first == !!(flags & SYMMETRIC_LEFT))
 			continue;
-		p->object.flags |= SEEN;
-		insert_by_date(p, list);
+
+		/*
+		 * Have we seen the same patch id?
+		 */
+		id = has_commit_patch_id(commit, &ids);
+		if (!id)
+			continue;
+		id->seen = 1;
+		commit->object.flags |= cherry_flag;
+	}
+
+	/* Now check the original side for seen ones */
+	for (p = list; p; p = p->next) {
+		struct commit *commit = p->item;
+		struct patch_id *ent;
+
+		ent = commit->util;
+		if (!ent)
+			continue;
+		if (ent->seen)
+			commit->object.flags |= cherry_flag;
+		commit->util = NULL;
+	}
+
+	free_patch_ids(&ids);
+}
+
+/* How many extra uninteresting commits we want to see.. */
+#define SLOP 5
+
+static int still_interesting(struct commit_list *src, unsigned long date, int slop)
+{
+	/*
+	 * No source list at all? We're definitely done..
+	 */
+	if (!src)
+		return 0;
+
+	/*
+	 * Does the destination list contain entries with a date
+	 * before the source list? Definitely _not_ done.
+	 */
+	if (date < src->item->date)
+		return SLOP;
+
+	/*
+	 * Does the source list still have interesting commits in
+	 * it? Definitely not done..
+	 */
+	if (!everybody_uninteresting(src))
+		return SLOP;
+
+	/* Ok, we're closing in.. */
+	return slop-1;
+}
+
+/*
+ * "rev-list --ancestry-path A..B" computes commits that are ancestors
+ * of B but not ancestors of A but further limits the result to those
+ * that are descendants of A.  This takes the list of bottom commits and
+ * the result of "A..B" without --ancestry-path, and limits the latter
+ * further to the ones that can reach one of the commits in "bottom".
+ */
+static void limit_to_ancestry(struct commit_list *bottom, struct commit_list *list)
+{
+	struct commit_list *p;
+	struct commit_list *rlist = NULL;
+	int made_progress;
+
+	/*
+	 * Reverse the list so that it will be likely that we would
+	 * process parents before children.
+	 */
+	for (p = list; p; p = p->next)
+		commit_list_insert(p->item, &rlist);
+
+	for (p = bottom; p; p = p->next)
+		p->item->object.flags |= TMP_MARK;
+
+	/*
+	 * Mark the ones that can reach bottom commits in "list",
+	 * in a bottom-up fashion.
+	 */
+	do {
+		made_progress = 0;
+		for (p = rlist; p; p = p->next) {
+			struct commit *c = p->item;
+			struct commit_list *parents;
+			if (c->object.flags & (TMP_MARK | UNINTERESTING))
+				continue;
+			for (parents = c->parents;
+			     parents;
+			     parents = parents->next) {
+				if (!(parents->item->object.flags & TMP_MARK))
+					continue;
+				c->object.flags |= TMP_MARK;
+				made_progress = 1;
+				break;
+			}
+		}
+	} while (made_progress);
+
+	/*
+	 * NEEDSWORK: decide if we want to remove parents that are
+	 * not marked with TMP_MARK from commit->parents for commits
+	 * in the resulting list.  We may not want to do that, though.
+	 */
+
+	/*
+	 * The ones that are not marked with TMP_MARK are uninteresting
+	 */
+	for (p = list; p; p = p->next) {
+		struct commit *c = p->item;
+		if (c->object.flags & TMP_MARK)
+			continue;
+		c->object.flags |= UNINTERESTING;
+	}
+
+	/* We are done with the TMP_MARK */
+	for (p = list; p; p = p->next)
+		p->item->object.flags &= ~TMP_MARK;
+	for (p = bottom; p; p = p->next)
+		p->item->object.flags &= ~TMP_MARK;
+	free_commit_list(rlist);
+}
+
+/*
+ * Before walking the history, keep the set of "negative" refs the
+ * caller has asked to exclude.
+ *
+ * This is used to compute "rev-list --ancestry-path A..B", as we need
+ * to filter the result of "A..B" further to the ones that can actually
+ * reach A.
+ */
+static struct commit_list *collect_bottom_commits(struct rev_info *revs)
+{
+	struct commit_list *bottom = NULL;
+	int i;
+	for (i = 0; i < revs->cmdline.nr; i++) {
+		struct rev_cmdline_entry *elem = &revs->cmdline.rev[i];
+		if ((elem->flags & UNINTERESTING) &&
+		    elem->item->type == OBJ_COMMIT)
+			commit_list_insert((struct commit *)elem->item, &bottom);
 	}
+	return bottom;
 }
 
-static void limit_list(struct rev_info *revs)
+/* Assumes either left_only or right_only is set */
+static void limit_left_right(struct commit_list *list, struct rev_info *revs)
 {
+	struct commit_list *p;
+
+	for (p = list; p; p = p->next) {
+		struct commit *commit = p->item;
+
+		if (revs->right_only) {
+			if (commit->object.flags & SYMMETRIC_LEFT)
+				commit->object.flags |= SHOWN;
+		} else	/* revs->left_only is set */
+			if (!(commit->object.flags & SYMMETRIC_LEFT))
+				commit->object.flags |= SHOWN;
+	}
+}
+
+static int limit_list(struct rev_info *revs)
+{
+	int slop = SLOP;
+	unsigned long date = ~0ul;
 	struct commit_list *list = revs->commits;
 	struct commit_list *newlist = NULL;
 	struct commit_list **p = &newlist;
+	struct commit_list *bottom = NULL;
 
-	if (revs->paths)
-		diff_tree_setup_paths(revs->paths);
+	if (revs->ancestry_path) {
+		bottom = collect_bottom_commits(revs);
+		if (!bottom)
+			die("--ancestry-path given but there are no bottom commits");
+	}
 
 	while (list) {
 		struct commit_list *entry = list;
 		struct commit *commit = list->item;
 		struct object *obj = &commit->object;
+		show_early_output_fn_t show;
 
 		list = list->next;
 		free(entry);
 
 		if (revs->max_age != -1 && (commit->date < revs->max_age))
 			obj->flags |= UNINTERESTING;
-		if (revs->unpacked && has_sha1_pack(obj->sha1))
-			obj->flags |= UNINTERESTING;
-		add_parents_to_list(revs, commit, &list);
+		if (add_parents_to_list(revs, commit, &list, NULL) < 0)
+			return -1;
 		if (obj->flags & UNINTERESTING) {
 			mark_parents_uninteresting(commit);
-			if (everybody_uninteresting(list))
-				break;
-			continue;
+			if (revs->show_all)
+				p = &commit_list_insert(commit, p)->next;
+			slop = still_interesting(list, date, slop);
+			if (slop)
+				continue;
+			/* If showing all, add the whole pending list to the end */
+			if (revs->show_all)
+				*p = list;
+			break;
 		}
 		if (revs->min_age != -1 && (commit->date > revs->min_age))
 			continue;
+		date = commit->date;
 		p = &commit_list_insert(commit, p)->next;
+
+		show = show_early_output;
+		if (!show)
+			continue;
+
+		show(revs, newlist);
+		show_early_output = NULL;
+	}
+	if (revs->cherry_pick || revs->cherry_mark)
+		cherry_pick_list(newlist, revs);
+
+	if (revs->left_only || revs->right_only)
+		limit_left_right(newlist, revs);
+
+	if (bottom) {
+		limit_to_ancestry(bottom, newlist);
+		free_commit_list(bottom);
 	}
+
 	revs->commits = newlist;
+	return 0;
 }
 
-static void add_one_commit(struct commit *commit, struct rev_info *revs)
+static void add_rev_cmdline(struct rev_info *revs,
+			    struct object *item,
+			    const char *name,
+			    int whence,
+			    unsigned flags)
 {
-	if (!commit || (commit->object.flags & SEEN))
-		return;
-	commit->object.flags |= SEEN;
-	commit_list_insert(commit, &revs->commits);
+	struct rev_cmdline_info *info = &revs->cmdline;
+	int nr = info->nr;
+
+	ALLOC_GROW(info->rev, nr + 1, info->alloc);
+	info->rev[nr].item = item;
+	info->rev[nr].name = name;
+	info->rev[nr].whence = whence;
+	info->rev[nr].flags = flags;
+	info->nr++;
+}
+
+struct all_refs_cb {
+	int all_flags;
+	int warned_bad_reflog;
+	struct rev_info *all_revs;
+	const char *name_for_errormsg;
+};
+
+static int handle_one_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
+{
+	struct all_refs_cb *cb = cb_data;
+	struct object *object = get_reference(cb->all_revs, path, sha1,
+					      cb->all_flags);
+	add_rev_cmdline(cb->all_revs, object, path, REV_CMD_REF, cb->all_flags);
+	add_pending_object(cb->all_revs, object, path);
+	return 0;
+}
+
+static void init_all_refs_cb(struct all_refs_cb *cb, struct rev_info *revs,
+	unsigned flags)
+{
+	cb->all_revs = revs;
+	cb->all_flags = flags;
+}
+
+static void handle_refs(const char *submodule, struct rev_info *revs, unsigned flags,
+		int (*for_each)(const char *, each_ref_fn, void *))
+{
+	struct all_refs_cb cb;
+	init_all_refs_cb(&cb, revs, flags);
+	for_each(submodule, handle_one_ref, &cb);
+}
+
+static void handle_one_reflog_commit(unsigned char *sha1, void *cb_data)
+{
+	struct all_refs_cb *cb = cb_data;
+	if (!is_null_sha1(sha1)) {
+		struct object *o = parse_object(sha1);
+		if (o) {
+			o->flags |= cb->all_flags;
+			/* ??? CMDLINEFLAGS ??? */
+			add_pending_object(cb->all_revs, o, "");
+		}
+		else if (!cb->warned_bad_reflog) {
+			warning("reflog of '%s' references pruned commits",
+				cb->name_for_errormsg);
+			cb->warned_bad_reflog = 1;
+		}
+	}
 }
 
-static int all_flags;
-static struct rev_info *all_revs;
+static int handle_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
+		const char *email, unsigned long timestamp, int tz,
+		const char *message, void *cb_data)
+{
+	handle_one_reflog_commit(osha1, cb_data);
+	handle_one_reflog_commit(nsha1, cb_data);
+	return 0;
+}
 
-static int handle_one_ref(const char *path, const unsigned char *sha1)
+static int handle_one_reflog(const char *path, const unsigned char *sha1, int flag, void *cb_data)
 {
-	struct commit *commit = get_commit_reference(all_revs, path, sha1, all_flags);
-	add_one_commit(commit, all_revs);
+	struct all_refs_cb *cb = cb_data;
+	cb->warned_bad_reflog = 0;
+	cb->name_for_errormsg = path;
+	for_each_reflog_ent(path, handle_one_reflog_ent, cb_data);
 	return 0;
 }
 
-static void handle_all(struct rev_info *revs, unsigned flags)
+static void handle_reflog(struct rev_info *revs, unsigned flags)
+{
+	struct all_refs_cb cb;
+	cb.all_revs = revs;
+	cb.all_flags = flags;
+	for_each_reflog(handle_one_reflog, &cb);
+}
+
+static int add_parents_only(struct rev_info *revs, const char *arg_, int flags)
+{
+	unsigned char sha1[20];
+	struct object *it;
+	struct commit *commit;
+	struct commit_list *parents;
+	const char *arg = arg_;
+
+	if (*arg == '^') {
+		flags ^= UNINTERESTING;
+		arg++;
+	}
+	if (get_sha1(arg, sha1))
+		return 0;
+	while (1) {
+		it = get_reference(revs, arg, sha1, 0);
+		if (!it && revs->ignore_missing)
+			return 0;
+		if (it->type != OBJ_TAG)
+			break;
+		if (!((struct tag*)it)->tagged)
+			return 0;
+		hashcpy(sha1, ((struct tag*)it)->tagged->sha1);
+	}
+	if (it->type != OBJ_COMMIT)
+		return 0;
+	commit = (struct commit *)it;
+	for (parents = commit->parents; parents; parents = parents->next) {
+		it = &parents->item->object;
+		it->flags |= flags;
+		add_rev_cmdline(revs, it, arg_, REV_CMD_PARENTS_ONLY, flags);
+		add_pending_object(revs, it, arg);
+	}
+	return 1;
+}
+
+void init_revisions(struct rev_info *revs, const char *prefix)
+{
+	memset(revs, 0, sizeof(*revs));
+
+	revs->abbrev = DEFAULT_ABBREV;
+	revs->ignore_merges = 1;
+	revs->simplify_history = 1;
+	DIFF_OPT_SET(&revs->pruning, RECURSIVE);
+	DIFF_OPT_SET(&revs->pruning, QUICK);
+	revs->pruning.add_remove = file_add_remove;
+	revs->pruning.change = file_change;
+	revs->lifo = 1;
+	revs->dense = 1;
+	revs->prefix = prefix;
+	revs->max_age = -1;
+	revs->min_age = -1;
+	revs->skip_count = -1;
+	revs->max_count = -1;
+	revs->max_parents = -1;
+
+	revs->commit_format = CMIT_FMT_DEFAULT;
+
+	revs->grep_filter.status_only = 1;
+	revs->grep_filter.pattern_tail = &(revs->grep_filter.pattern_list);
+	revs->grep_filter.header_tail = &(revs->grep_filter.header_list);
+	revs->grep_filter.regflags = REG_NEWLINE;
+
+	diff_setup(&revs->diffopt);
+	if (prefix && !revs->diffopt.prefix) {
+		revs->diffopt.prefix = prefix;
+		revs->diffopt.prefix_length = strlen(prefix);
+	}
+
+	revs->notes_opt.use_default_notes = -1;
+}
+
+static void add_pending_commit_list(struct rev_info *revs,
+                                    struct commit_list *commit_list,
+                                    unsigned int flags)
+{
+	while (commit_list) {
+		struct object *object = &commit_list->item->object;
+		object->flags |= flags;
+		add_pending_object(revs, object, sha1_to_hex(object->sha1));
+		commit_list = commit_list->next;
+	}
+}
+
+static void prepare_show_merge(struct rev_info *revs)
+{
+	struct commit_list *bases;
+	struct commit *head, *other;
+	unsigned char sha1[20];
+	const char **prune = NULL;
+	int i, prune_num = 1; /* counting terminating NULL */
+
+	if (get_sha1("HEAD", sha1))
+		die("--merge without HEAD?");
+	head = lookup_commit_or_die(sha1, "HEAD");
+	if (get_sha1("MERGE_HEAD", sha1))
+		die("--merge without MERGE_HEAD?");
+	other = lookup_commit_or_die(sha1, "MERGE_HEAD");
+	add_pending_object(revs, &head->object, "HEAD");
+	add_pending_object(revs, &other->object, "MERGE_HEAD");
+	bases = get_merge_bases(head, other, 1);
+	add_pending_commit_list(revs, bases, UNINTERESTING);
+	free_commit_list(bases);
+	head->object.flags |= SYMMETRIC_LEFT;
+
+	if (!active_nr)
+		read_cache();
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce = active_cache[i];
+		if (!ce_stage(ce))
+			continue;
+		if (ce_path_match(ce, &revs->prune_data)) {
+			prune_num++;
+			prune = xrealloc(prune, sizeof(*prune) * prune_num);
+			prune[prune_num-2] = ce->name;
+			prune[prune_num-1] = NULL;
+		}
+		while ((i+1 < active_nr) &&
+		       ce_same_name(ce, active_cache[i+1]))
+			i++;
+	}
+	free_pathspec(&revs->prune_data);
+	init_pathspec(&revs->prune_data, prune);
+	revs->limited = 1;
+}
+
+int handle_revision_arg(const char *arg_, struct rev_info *revs,
+			int flags,
+			int cant_be_filename)
+{
+	unsigned mode;
+	char *dotdot;
+	struct object *object;
+	unsigned char sha1[20];
+	int local_flags;
+	const char *arg = arg_;
+
+	dotdot = strstr(arg, "..");
+	if (dotdot) {
+		unsigned char from_sha1[20];
+		const char *next = dotdot + 2;
+		const char *this = arg;
+		int symmetric = *next == '.';
+		unsigned int flags_exclude = flags ^ UNINTERESTING;
+		unsigned int a_flags;
+
+		*dotdot = 0;
+		next += symmetric;
+
+		if (!*next)
+			next = "HEAD";
+		if (dotdot == arg)
+			this = "HEAD";
+		if (!get_sha1(this, from_sha1) &&
+		    !get_sha1(next, sha1)) {
+			struct commit *a, *b;
+			struct commit_list *exclude;
+
+			a = lookup_commit_reference(from_sha1);
+			b = lookup_commit_reference(sha1);
+			if (!a || !b) {
+				if (revs->ignore_missing)
+					return 0;
+				die(symmetric ?
+				    "Invalid symmetric difference expression %s...%s" :
+				    "Invalid revision range %s..%s",
+				    arg, next);
+			}
+
+			if (!cant_be_filename) {
+				*dotdot = '.';
+				verify_non_filename(revs->prefix, arg);
+			}
+
+			if (symmetric) {
+				exclude = get_merge_bases(a, b, 1);
+				add_pending_commit_list(revs, exclude,
+							flags_exclude);
+				free_commit_list(exclude);
+				a_flags = flags | SYMMETRIC_LEFT;
+			} else
+				a_flags = flags_exclude;
+			a->object.flags |= a_flags;
+			b->object.flags |= flags;
+			add_rev_cmdline(revs, &a->object, this,
+					REV_CMD_LEFT, a_flags);
+			add_rev_cmdline(revs, &b->object, next,
+					REV_CMD_RIGHT, flags);
+			add_pending_object(revs, &a->object, this);
+			add_pending_object(revs, &b->object, next);
+			return 0;
+		}
+		*dotdot = '.';
+	}
+	dotdot = strstr(arg, "^@");
+	if (dotdot && !dotdot[2]) {
+		*dotdot = 0;
+		if (add_parents_only(revs, arg, flags))
+			return 0;
+		*dotdot = '^';
+	}
+	dotdot = strstr(arg, "^!");
+	if (dotdot && !dotdot[2]) {
+		*dotdot = 0;
+		if (!add_parents_only(revs, arg, flags ^ UNINTERESTING))
+			*dotdot = '^';
+	}
+
+	local_flags = 0;
+	if (*arg == '^') {
+		local_flags = UNINTERESTING;
+		arg++;
+	}
+	if (get_sha1_with_mode(arg, sha1, &mode))
+		return revs->ignore_missing ? 0 : -1;
+	if (!cant_be_filename)
+		verify_non_filename(revs->prefix, arg);
+	object = get_reference(revs, arg, sha1, flags ^ local_flags);
+	add_rev_cmdline(revs, object, arg_, REV_CMD_REV, flags ^ local_flags);
+	add_pending_object_with_mode(revs, object, arg, mode);
+	return 0;
+}
+
+struct cmdline_pathspec {
+	int alloc;
+	int nr;
+	const char **path;
+};
+
+static void append_prune_data(struct cmdline_pathspec *prune, const char **av)
+{
+	while (*av) {
+		ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
+		prune->path[prune->nr++] = *(av++);
+	}
+}
+
+static void read_pathspec_from_stdin(struct rev_info *revs, struct strbuf *sb,
+				     struct cmdline_pathspec *prune)
+{
+	while (strbuf_getwholeline(sb, stdin, '\n') != EOF) {
+		int len = sb->len;
+		if (len && sb->buf[len - 1] == '\n')
+			sb->buf[--len] = '\0';
+		ALLOC_GROW(prune->path, prune->nr+1, prune->alloc);
+		prune->path[prune->nr++] = xstrdup(sb->buf);
+	}
+}
+
+static void read_revisions_from_stdin(struct rev_info *revs,
+				      struct cmdline_pathspec *prune)
+{
+	struct strbuf sb;
+	int seen_dashdash = 0;
+
+	strbuf_init(&sb, 1000);
+	while (strbuf_getwholeline(&sb, stdin, '\n') != EOF) {
+		int len = sb.len;
+		if (len && sb.buf[len - 1] == '\n')
+			sb.buf[--len] = '\0';
+		if (!len)
+			break;
+		if (sb.buf[0] == '-') {
+			if (len == 2 && sb.buf[1] == '-') {
+				seen_dashdash = 1;
+				break;
+			}
+			die("options not supported in --stdin mode");
+		}
+		if (handle_revision_arg(sb.buf, revs, 0, 1))
+			die("bad revision '%s'", sb.buf);
+	}
+	if (seen_dashdash)
+		read_pathspec_from_stdin(revs, &sb, prune);
+	strbuf_release(&sb);
+}
+
+static void add_grep(struct rev_info *revs, const char *ptn, enum grep_pat_token what)
+{
+	append_grep_pattern(&revs->grep_filter, ptn, "command line", 0, what);
+}
+
+static void add_header_grep(struct rev_info *revs, enum grep_header_field field, const char *pattern)
+{
+	append_header_grep_pattern(&revs->grep_filter, field, pattern);
+}
+
+static void add_message_grep(struct rev_info *revs, const char *pattern)
+{
+	add_grep(revs, pattern, GREP_PATTERN_BODY);
+}
+
+static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
+			       int *unkc, const char **unkv)
+{
+	const char *arg = argv[0];
+	const char *optarg;
+	int argcount;
+
+	/* pseudo revision arguments */
+	if (!strcmp(arg, "--all") || !strcmp(arg, "--branches") ||
+	    !strcmp(arg, "--tags") || !strcmp(arg, "--remotes") ||
+	    !strcmp(arg, "--reflog") || !strcmp(arg, "--not") ||
+	    !strcmp(arg, "--no-walk") || !strcmp(arg, "--do-walk") ||
+	    !strcmp(arg, "--bisect") || !prefixcmp(arg, "--glob=") ||
+	    !prefixcmp(arg, "--branches=") || !prefixcmp(arg, "--tags=") ||
+	    !prefixcmp(arg, "--remotes="))
+	{
+		unkv[(*unkc)++] = arg;
+		return 1;
+	}
+
+	if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
+		revs->max_count = atoi(optarg);
+		revs->no_walk = 0;
+		return argcount;
+	} else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
+		revs->skip_count = atoi(optarg);
+		return argcount;
+	} else if ((*arg == '-') && isdigit(arg[1])) {
+	/* accept -<digit>, like traditional "head" */
+		revs->max_count = atoi(arg + 1);
+		revs->no_walk = 0;
+	} else if (!strcmp(arg, "-n")) {
+		if (argc <= 1)
+			return error("-n requires an argument");
+		revs->max_count = atoi(argv[1]);
+		revs->no_walk = 0;
+		return 2;
+	} else if (!prefixcmp(arg, "-n")) {
+		revs->max_count = atoi(arg + 2);
+		revs->no_walk = 0;
+	} else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
+		revs->max_age = atoi(optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("since", argv, &optarg))) {
+		revs->max_age = approxidate(optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("after", argv, &optarg))) {
+		revs->max_age = approxidate(optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
+		revs->min_age = atoi(optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("before", argv, &optarg))) {
+		revs->min_age = approxidate(optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("until", argv, &optarg))) {
+		revs->min_age = approxidate(optarg);
+		return argcount;
+	} else if (!strcmp(arg, "--first-parent")) {
+		revs->first_parent_only = 1;
+	} else if (!strcmp(arg, "--ancestry-path")) {
+		revs->ancestry_path = 1;
+		revs->simplify_history = 0;
+		revs->limited = 1;
+	} else if (!strcmp(arg, "-g") || !strcmp(arg, "--walk-reflogs")) {
+		init_reflog_walk(&revs->reflog_info);
+	} else if (!strcmp(arg, "--default")) {
+		if (argc <= 1)
+			return error("bad --default argument");
+		revs->def = argv[1];
+		return 2;
+	} else if (!strcmp(arg, "--merge")) {
+		revs->show_merge = 1;
+	} else if (!strcmp(arg, "--topo-order")) {
+		revs->lifo = 1;
+		revs->topo_order = 1;
+	} else if (!strcmp(arg, "--simplify-merges")) {
+		revs->simplify_merges = 1;
+		revs->rewrite_parents = 1;
+		revs->simplify_history = 0;
+		revs->limited = 1;
+	} else if (!strcmp(arg, "--simplify-by-decoration")) {
+		revs->simplify_merges = 1;
+		revs->rewrite_parents = 1;
+		revs->simplify_history = 0;
+		revs->simplify_by_decoration = 1;
+		revs->limited = 1;
+		revs->prune = 1;
+		load_ref_decorations(DECORATE_SHORT_REFS);
+	} else if (!strcmp(arg, "--date-order")) {
+		revs->lifo = 0;
+		revs->topo_order = 1;
+	} else if (!prefixcmp(arg, "--early-output")) {
+		int count = 100;
+		switch (arg[14]) {
+		case '=':
+			count = atoi(arg+15);
+			/* Fallthrough */
+		case 0:
+			revs->topo_order = 1;
+		       revs->early_output = count;
+		}
+	} else if (!strcmp(arg, "--parents")) {
+		revs->rewrite_parents = 1;
+		revs->print_parents = 1;
+	} else if (!strcmp(arg, "--dense")) {
+		revs->dense = 1;
+	} else if (!strcmp(arg, "--sparse")) {
+		revs->dense = 0;
+	} else if (!strcmp(arg, "--show-all")) {
+		revs->show_all = 1;
+	} else if (!strcmp(arg, "--remove-empty")) {
+		revs->remove_empty_trees = 1;
+	} else if (!strcmp(arg, "--merges")) {
+		revs->min_parents = 2;
+	} else if (!strcmp(arg, "--no-merges")) {
+		revs->max_parents = 1;
+	} else if (!prefixcmp(arg, "--min-parents=")) {
+		revs->min_parents = atoi(arg+14);
+	} else if (!prefixcmp(arg, "--no-min-parents")) {
+		revs->min_parents = 0;
+	} else if (!prefixcmp(arg, "--max-parents=")) {
+		revs->max_parents = atoi(arg+14);
+	} else if (!prefixcmp(arg, "--no-max-parents")) {
+		revs->max_parents = -1;
+	} else if (!strcmp(arg, "--boundary")) {
+		revs->boundary = 1;
+	} else if (!strcmp(arg, "--left-right")) {
+		revs->left_right = 1;
+	} else if (!strcmp(arg, "--left-only")) {
+		if (revs->right_only)
+			die("--left-only is incompatible with --right-only"
+			    " or --cherry");
+		revs->left_only = 1;
+	} else if (!strcmp(arg, "--right-only")) {
+		if (revs->left_only)
+			die("--right-only is incompatible with --left-only");
+		revs->right_only = 1;
+	} else if (!strcmp(arg, "--cherry")) {
+		if (revs->left_only)
+			die("--cherry is incompatible with --left-only");
+		revs->cherry_mark = 1;
+		revs->right_only = 1;
+		revs->max_parents = 1;
+		revs->limited = 1;
+	} else if (!strcmp(arg, "--count")) {
+		revs->count = 1;
+	} else if (!strcmp(arg, "--cherry-mark")) {
+		if (revs->cherry_pick)
+			die("--cherry-mark is incompatible with --cherry-pick");
+		revs->cherry_mark = 1;
+		revs->limited = 1; /* needs limit_list() */
+	} else if (!strcmp(arg, "--cherry-pick")) {
+		if (revs->cherry_mark)
+			die("--cherry-pick is incompatible with --cherry-mark");
+		revs->cherry_pick = 1;
+		revs->limited = 1;
+	} else if (!strcmp(arg, "--objects")) {
+		revs->tag_objects = 1;
+		revs->tree_objects = 1;
+		revs->blob_objects = 1;
+	} else if (!strcmp(arg, "--objects-edge")) {
+		revs->tag_objects = 1;
+		revs->tree_objects = 1;
+		revs->blob_objects = 1;
+		revs->edge_hint = 1;
+	} else if (!strcmp(arg, "--unpacked")) {
+		revs->unpacked = 1;
+	} else if (!prefixcmp(arg, "--unpacked=")) {
+		die("--unpacked=<packfile> no longer supported.");
+	} else if (!strcmp(arg, "-r")) {
+		revs->diff = 1;
+		DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
+	} else if (!strcmp(arg, "-t")) {
+		revs->diff = 1;
+		DIFF_OPT_SET(&revs->diffopt, RECURSIVE);
+		DIFF_OPT_SET(&revs->diffopt, TREE_IN_RECURSIVE);
+	} else if (!strcmp(arg, "-m")) {
+		revs->ignore_merges = 0;
+	} else if (!strcmp(arg, "-c")) {
+		revs->diff = 1;
+		revs->dense_combined_merges = 0;
+		revs->combine_merges = 1;
+	} else if (!strcmp(arg, "--cc")) {
+		revs->diff = 1;
+		revs->dense_combined_merges = 1;
+		revs->combine_merges = 1;
+	} else if (!strcmp(arg, "-v")) {
+		revs->verbose_header = 1;
+	} else if (!strcmp(arg, "--pretty")) {
+		revs->verbose_header = 1;
+		revs->pretty_given = 1;
+		get_commit_format(arg+8, revs);
+	} else if (!prefixcmp(arg, "--pretty=") || !prefixcmp(arg, "--format=")) {
+		/*
+		 * Detached form ("--pretty X" as opposed to "--pretty=X")
+		 * not allowed, since the argument is optional.
+		 */
+		revs->verbose_header = 1;
+		revs->pretty_given = 1;
+		get_commit_format(arg+9, revs);
+	} else if (!strcmp(arg, "--show-notes") || !strcmp(arg, "--notes")) {
+		revs->show_notes = 1;
+		revs->show_notes_given = 1;
+		revs->notes_opt.use_default_notes = 1;
+	} else if (!prefixcmp(arg, "--show-notes=") ||
+		   !prefixcmp(arg, "--notes=")) {
+		struct strbuf buf = STRBUF_INIT;
+		revs->show_notes = 1;
+		revs->show_notes_given = 1;
+		if (!prefixcmp(arg, "--show-notes")) {
+			if (revs->notes_opt.use_default_notes < 0)
+				revs->notes_opt.use_default_notes = 1;
+			strbuf_addstr(&buf, arg+13);
+		}
+		else
+			strbuf_addstr(&buf, arg+8);
+		expand_notes_ref(&buf);
+		string_list_append(&revs->notes_opt.extra_notes_refs,
+				   strbuf_detach(&buf, NULL));
+	} else if (!strcmp(arg, "--no-notes")) {
+		revs->show_notes = 0;
+		revs->show_notes_given = 1;
+		revs->notes_opt.use_default_notes = -1;
+		/* we have been strdup'ing ourselves, so trick
+		 * string_list into free()ing strings */
+		revs->notes_opt.extra_notes_refs.strdup_strings = 1;
+		string_list_clear(&revs->notes_opt.extra_notes_refs, 0);
+		revs->notes_opt.extra_notes_refs.strdup_strings = 0;
+	} else if (!strcmp(arg, "--standard-notes")) {
+		revs->show_notes_given = 1;
+		revs->notes_opt.use_default_notes = 1;
+	} else if (!strcmp(arg, "--no-standard-notes")) {
+		revs->notes_opt.use_default_notes = 0;
+	} else if (!strcmp(arg, "--oneline")) {
+		revs->verbose_header = 1;
+		get_commit_format("oneline", revs);
+		revs->pretty_given = 1;
+		revs->abbrev_commit = 1;
+	} else if (!strcmp(arg, "--graph")) {
+		revs->topo_order = 1;
+		revs->rewrite_parents = 1;
+		revs->graph = graph_init(revs);
+	} else if (!strcmp(arg, "--root")) {
+		revs->show_root_diff = 1;
+	} else if (!strcmp(arg, "--no-commit-id")) {
+		revs->no_commit_id = 1;
+	} else if (!strcmp(arg, "--always")) {
+		revs->always_show_header = 1;
+	} else if (!strcmp(arg, "--no-abbrev")) {
+		revs->abbrev = 0;
+	} else if (!strcmp(arg, "--abbrev")) {
+		revs->abbrev = DEFAULT_ABBREV;
+	} else if (!prefixcmp(arg, "--abbrev=")) {
+		revs->abbrev = strtoul(arg + 9, NULL, 10);
+		if (revs->abbrev < MINIMUM_ABBREV)
+			revs->abbrev = MINIMUM_ABBREV;
+		else if (revs->abbrev > 40)
+			revs->abbrev = 40;
+	} else if (!strcmp(arg, "--abbrev-commit")) {
+		revs->abbrev_commit = 1;
+		revs->abbrev_commit_given = 1;
+	} else if (!strcmp(arg, "--no-abbrev-commit")) {
+		revs->abbrev_commit = 0;
+	} else if (!strcmp(arg, "--full-diff")) {
+		revs->diff = 1;
+		revs->full_diff = 1;
+	} else if (!strcmp(arg, "--full-history")) {
+		revs->simplify_history = 0;
+	} else if (!strcmp(arg, "--relative-date")) {
+		revs->date_mode = DATE_RELATIVE;
+		revs->date_mode_explicit = 1;
+	} else if ((argcount = parse_long_opt("date", argv, &optarg))) {
+		revs->date_mode = parse_date_format(optarg);
+		revs->date_mode_explicit = 1;
+		return argcount;
+	} else if (!strcmp(arg, "--log-size")) {
+		revs->show_log_size = 1;
+	}
+	/*
+	 * Grepping the commit log
+	 */
+	else if ((argcount = parse_long_opt("author", argv, &optarg))) {
+		add_header_grep(revs, GREP_HEADER_AUTHOR, optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("committer", argv, &optarg))) {
+		add_header_grep(revs, GREP_HEADER_COMMITTER, optarg);
+		return argcount;
+	} else if ((argcount = parse_long_opt("grep", argv, &optarg))) {
+		add_message_grep(revs, optarg);
+		return argcount;
+	} else if (!strcmp(arg, "--extended-regexp") || !strcmp(arg, "-E")) {
+		revs->grep_filter.regflags |= REG_EXTENDED;
+	} else if (!strcmp(arg, "--regexp-ignore-case") || !strcmp(arg, "-i")) {
+		revs->grep_filter.regflags |= REG_ICASE;
+	} else if (!strcmp(arg, "--fixed-strings") || !strcmp(arg, "-F")) {
+		revs->grep_filter.fixed = 1;
+	} else if (!strcmp(arg, "--all-match")) {
+		revs->grep_filter.all_match = 1;
+	} else if ((argcount = parse_long_opt("encoding", argv, &optarg))) {
+		if (strcmp(optarg, "none"))
+			git_log_output_encoding = xstrdup(optarg);
+		else
+			git_log_output_encoding = "";
+		return argcount;
+	} else if (!strcmp(arg, "--reverse")) {
+		revs->reverse ^= 1;
+	} else if (!strcmp(arg, "--children")) {
+		revs->children.name = "children";
+		revs->limited = 1;
+	} else if (!strcmp(arg, "--ignore-missing")) {
+		revs->ignore_missing = 1;
+	} else {
+		int opts = diff_opt_parse(&revs->diffopt, argv, argc);
+		if (!opts)
+			unkv[(*unkc)++] = arg;
+		return opts;
+	}
+
+	return 1;
+}
+
+void parse_revision_opt(struct rev_info *revs, struct parse_opt_ctx_t *ctx,
+			const struct option *options,
+			const char * const usagestr[])
 {
-	all_revs = revs;
-	all_flags = flags;
-	for_each_ref(handle_one_ref);
+	int n = handle_revision_opt(revs, ctx->argc, ctx->argv,
+				    &ctx->cpidx, ctx->out);
+	if (n <= 0) {
+		error("unknown option `%s'", ctx->argv[0]);
+		usage_with_options(usagestr, options);
+	}
+	ctx->argv += n;
+	ctx->argc -= n;
+}
+
+static int for_each_bad_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+	return for_each_ref_in_submodule(submodule, "refs/bisect/bad", fn, cb_data);
+}
+
+static int for_each_good_bisect_ref(const char *submodule, each_ref_fn fn, void *cb_data)
+{
+	return for_each_ref_in_submodule(submodule, "refs/bisect/good", fn, cb_data);
+}
+
+static int handle_revision_pseudo_opt(const char *submodule,
+				struct rev_info *revs,
+				int argc, const char **argv, int *flags)
+{
+	const char *arg = argv[0];
+	const char *optarg;
+	int argcount;
+
+	/*
+	 * NOTE!
+	 *
+	 * Commands like "git shortlog" will not accept the options below
+	 * unless parse_revision_opt queues them (as opposed to erroring
+	 * out).
+	 *
+	 * When implementing your new pseudo-option, remember to
+	 * register it in the list at the top of handle_revision_opt.
+	 */
+	if (!strcmp(arg, "--all")) {
+		handle_refs(submodule, revs, *flags, for_each_ref_submodule);
+		handle_refs(submodule, revs, *flags, head_ref_submodule);
+	} else if (!strcmp(arg, "--branches")) {
+		handle_refs(submodule, revs, *flags, for_each_branch_ref_submodule);
+	} else if (!strcmp(arg, "--bisect")) {
+		handle_refs(submodule, revs, *flags, for_each_bad_bisect_ref);
+		handle_refs(submodule, revs, *flags ^ UNINTERESTING, for_each_good_bisect_ref);
+		revs->bisect = 1;
+	} else if (!strcmp(arg, "--tags")) {
+		handle_refs(submodule, revs, *flags, for_each_tag_ref_submodule);
+	} else if (!strcmp(arg, "--remotes")) {
+		handle_refs(submodule, revs, *flags, for_each_remote_ref_submodule);
+	} else if ((argcount = parse_long_opt("glob", argv, &optarg))) {
+		struct all_refs_cb cb;
+		init_all_refs_cb(&cb, revs, *flags);
+		for_each_glob_ref(handle_one_ref, optarg, &cb);
+		return argcount;
+	} else if (!prefixcmp(arg, "--branches=")) {
+		struct all_refs_cb cb;
+		init_all_refs_cb(&cb, revs, *flags);
+		for_each_glob_ref_in(handle_one_ref, arg + 11, "refs/heads/", &cb);
+	} else if (!prefixcmp(arg, "--tags=")) {
+		struct all_refs_cb cb;
+		init_all_refs_cb(&cb, revs, *flags);
+		for_each_glob_ref_in(handle_one_ref, arg + 7, "refs/tags/", &cb);
+	} else if (!prefixcmp(arg, "--remotes=")) {
+		struct all_refs_cb cb;
+		init_all_refs_cb(&cb, revs, *flags);
+		for_each_glob_ref_in(handle_one_ref, arg + 10, "refs/remotes/", &cb);
+	} else if (!strcmp(arg, "--reflog")) {
+		handle_reflog(revs, *flags);
+	} else if (!strcmp(arg, "--not")) {
+		*flags ^= UNINTERESTING;
+	} else if (!strcmp(arg, "--no-walk")) {
+		revs->no_walk = 1;
+	} else if (!strcmp(arg, "--do-walk")) {
+		revs->no_walk = 0;
+	} else {
+		return 0;
+	}
+
+	return 1;
 }
 
 /*
@@ -452,19 +1627,15 @@ static void handle_all(struct rev_info *revs, unsigned flags)
  * Returns the number of arguments left that weren't recognized
  * (which are also moved to the head of the argument list)
  */
-int setup_revisions(int argc, const char **argv, struct rev_info *revs, const char *def)
+int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct setup_revision_opt *opt)
 {
-	int i, flags, seen_dashdash;
-	const char **unrecognized = argv + 1;
-	int left = 1;
+	int i, flags, left, seen_dashdash, read_from_stdin, got_rev_arg = 0;
+	struct cmdline_pathspec prune_data;
+	const char *submodule = NULL;
 
-	memset(revs, 0, sizeof(*revs));
-	revs->lifo = 1;
-	revs->dense = 1;
-	revs->prefix = setup_git_directory();
-	revs->max_age = -1;
-	revs->min_age = -1;
-	revs->max_count = -1;
+	memset(&prune_data, 0, sizeof(prune_data));
+	if (opt)
+		submodule = opt->submodule;
 
 	/* First, search for "--" */
 	seen_dashdash = 0;
@@ -474,263 +1645,735 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 			continue;
 		argv[i] = NULL;
 		argc = i;
-		revs->paths = get_pathspec(revs->prefix, argv + i + 1);
+		if (argv[i + 1])
+			append_prune_data(&prune_data, argv + i + 1);
 		seen_dashdash = 1;
 		break;
 	}
 
+	/* Second, deal with arguments and options */
 	flags = 0;
-	for (i = 1; i < argc; i++) {
-		struct commit *commit;
+	read_from_stdin = 0;
+	for (left = i = 1; i < argc; i++) {
 		const char *arg = argv[i];
-		unsigned char sha1[20];
-		char *dotdot;
-		int local_flags;
-
 		if (*arg == '-') {
-			if (!strncmp(arg, "--max-count=", 12)) {
-				revs->max_count = atoi(arg + 12);
-				continue;
-			}
-			/* accept -<digit>, like traditilnal "head" */
-			if ((*arg == '-') && isdigit(arg[1])) {
-				revs->max_count = atoi(arg + 1);
-				continue;
-			}
-			if (!strcmp(arg, "-n")) {
-				if (argc <= i + 1)
-					die("-n requires an argument");
-				revs->max_count = atoi(argv[++i]);
-				continue;
-			}
-			if (!strncmp(arg,"-n",2)) {
-				revs->max_count = atoi(arg + 2);
-				continue;
-			}
-			if (!strncmp(arg, "--max-age=", 10)) {
-				revs->max_age = atoi(arg + 10);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--min-age=", 10)) {
-				revs->min_age = atoi(arg + 10);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--since=", 8)) {
-				revs->max_age = approxidate(arg + 8);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--after=", 8)) {
-				revs->max_age = approxidate(arg + 8);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--before=", 9)) {
-				revs->min_age = approxidate(arg + 9);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--until=", 8)) {
-				revs->min_age = approxidate(arg + 8);
-				revs->limited = 1;
-				continue;
-			}
-			if (!strcmp(arg, "--all")) {
-				handle_all(revs, flags);
-				continue;
-			}
-			if (!strcmp(arg, "--not")) {
-				flags ^= UNINTERESTING;
-				continue;
-			}
-			if (!strcmp(arg, "--default")) {
-				if (++i >= argc)
-					die("bad --default argument");
-				def = argv[i];
-				continue;
-			}
-			if (!strcmp(arg, "--topo-order")) {
-				revs->topo_order = 1;
-				revs->limited = 1;
-				continue;
-			}
-			if (!strcmp(arg, "--date-order")) {
-				revs->lifo = 0;
-				revs->topo_order = 1;
-				revs->limited = 1;
-				continue;
-			}
-			if (!strcmp(arg, "--dense")) {
-				revs->dense = 1;
-				continue;
-			}
-			if (!strcmp(arg, "--sparse")) {
-				revs->dense = 0;
-				continue;
-			}
-			if (!strcmp(arg, "--remove-empty")) {
-				revs->remove_empty_trees = 1;
-				continue;
-			}
-			if (!strncmp(arg, "--no-merges", 11)) {
-				revs->no_merges = 1;
-				continue;
-			}
-			if (!strcmp(arg, "--objects")) {
-				revs->tag_objects = 1;
-				revs->tree_objects = 1;
-				revs->blob_objects = 1;
+			int opts;
+
+			opts = handle_revision_pseudo_opt(submodule,
+						revs, argc - i, argv + i,
+						&flags);
+			if (opts > 0) {
+				i += opts - 1;
 				continue;
 			}
-			if (!strcmp(arg, "--objects-edge")) {
-				revs->tag_objects = 1;
-				revs->tree_objects = 1;
-				revs->blob_objects = 1;
-				revs->edge_hint = 1;
+
+			if (!strcmp(arg, "--stdin")) {
+				if (revs->disable_stdin) {
+					argv[left++] = arg;
+					continue;
+				}
+				if (read_from_stdin++)
+					die("--stdin given twice?");
+				read_revisions_from_stdin(revs, &prune_data);
 				continue;
 			}
-			if (!strcmp(arg, "--unpacked")) {
-				revs->unpacked = 1;
-				revs->limited = 1;
+
+			opts = handle_revision_opt(revs, argc - i, argv + i, &left, argv);
+			if (opts > 0) {
+				i += opts - 1;
 				continue;
 			}
-			*unrecognized++ = arg;
-			left++;
+			if (opts < 0)
+				exit(128);
 			continue;
 		}
-		dotdot = strstr(arg, "..");
-		if (dotdot) {
-			unsigned char from_sha1[20];
-			char *next = dotdot + 2;
-			*dotdot = 0;
-			if (!*next)
-				next = "HEAD";
-			if (!get_sha1(arg, from_sha1) && !get_sha1(next, sha1)) {
-				struct commit *exclude;
-				struct commit *include;
-
-				exclude = get_commit_reference(revs, arg, from_sha1, flags ^ UNINTERESTING);
-				include = get_commit_reference(revs, next, sha1, flags);
-				if (!exclude || !include)
-					die("Invalid revision range %s..%s", arg, next);
-				add_one_commit(exclude, revs);
-				add_one_commit(include, revs);
-				continue;
-			}
-			*dotdot = '.';
-		}
-		local_flags = 0;
-		if (*arg == '^') {
-			local_flags = UNINTERESTING;
-			arg++;
-		}
-		if (get_sha1(arg, sha1) < 0) {
-			struct stat st;
-			int j;
 
-			if (seen_dashdash || local_flags)
+		if (handle_revision_arg(arg, revs, flags, seen_dashdash)) {
+			int j;
+			if (seen_dashdash || *arg == '^')
 				die("bad revision '%s'", arg);
 
-			/* If we didn't have a "--", all filenames must exist */
-			for (j = i; j < argc; j++) {
-				if (lstat(argv[j], &st) < 0)
-					die("'%s': %s", arg, strerror(errno));
-			}
-			revs->paths = get_pathspec(revs->prefix, argv + i);
+			/* If we didn't have a "--":
+			 * (1) all filenames must exist;
+			 * (2) all rev-args must not be interpretable
+			 *     as a valid filename.
+			 * but the latter we have checked in the main loop.
+			 */
+			for (j = i; j < argc; j++)
+				verify_filename(revs->prefix, argv[j]);
+
+			append_prune_data(&prune_data, argv + i);
 			break;
 		}
-		commit = get_commit_reference(revs, arg, sha1, flags ^ local_flags);
-		add_one_commit(commit, revs);
+		else
+			got_rev_arg = 1;
 	}
-	if (def && !revs->commits) {
+
+	if (prune_data.nr) {
+		/*
+		 * If we need to introduce the magic "a lone ':' means no
+		 * pathspec whatsoever", here is the place to do so.
+		 *
+		 * if (prune_data.nr == 1 && !strcmp(prune_data[0], ":")) {
+		 *	prune_data.nr = 0;
+		 *	prune_data.alloc = 0;
+		 *	free(prune_data.path);
+		 *	prune_data.path = NULL;
+		 * } else {
+		 *	terminate prune_data.alloc with NULL and
+		 *	call init_pathspec() to set revs->prune_data here.
+		 * }
+		 */
+		ALLOC_GROW(prune_data.path, prune_data.nr+1, prune_data.alloc);
+		prune_data.path[prune_data.nr++] = NULL;
+		init_pathspec(&revs->prune_data,
+			      get_pathspec(revs->prefix, prune_data.path));
+	}
+
+	if (revs->def == NULL)
+		revs->def = opt ? opt->def : NULL;
+	if (opt && opt->tweak)
+		opt->tweak(revs, opt);
+	if (revs->show_merge)
+		prepare_show_merge(revs);
+	if (revs->def && !revs->pending.nr && !got_rev_arg) {
 		unsigned char sha1[20];
-		struct commit *commit;
-		if (get_sha1(def, sha1) < 0)
-			die("bad default revision '%s'", def);
-		commit = get_commit_reference(revs, def, sha1, 0);
-		add_one_commit(commit, revs);
+		struct object *object;
+		unsigned mode;
+		if (get_sha1_with_mode(revs->def, sha1, &mode))
+			die("bad default revision '%s'", revs->def);
+		object = get_reference(revs, revs->def, sha1, 0);
+		add_pending_object_with_mode(revs, object, revs->def, mode);
 	}
-	if (revs->paths)
+
+	/* Did the user ask for any diff output? Run the diff! */
+	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
+		revs->diff = 1;
+
+	/* Pickaxe, diff-filter and rename following need diffs */
+	if (revs->diffopt.pickaxe ||
+	    revs->diffopt.filter ||
+	    DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
+		revs->diff = 1;
+
+	if (revs->topo_order)
 		revs->limited = 1;
+
+	if (revs->prune_data.nr) {
+		diff_tree_setup_paths(revs->prune_data.raw, &revs->pruning);
+		/* Can't prune commits with rename following: the paths change.. */
+		if (!DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
+			revs->prune = 1;
+		if (!revs->full_diff)
+			diff_tree_setup_paths(revs->prune_data.raw, &revs->diffopt);
+	}
+	if (revs->combine_merges)
+		revs->ignore_merges = 0;
+	revs->diffopt.abbrev = revs->abbrev;
+	if (diff_setup_done(&revs->diffopt) < 0)
+		die("diff_setup_done failed");
+
+	compile_grep_patterns(&revs->grep_filter);
+
+	if (revs->reverse && revs->reflog_info)
+		die("cannot combine --reverse with --walk-reflogs");
+	if (revs->rewrite_parents && revs->children.name)
+		die("cannot combine --parents and --children");
+
+	/*
+	 * Limitations on the graph functionality
+	 */
+	if (revs->reverse && revs->graph)
+		die("cannot combine --reverse with --graph");
+
+	if (revs->reflog_info && revs->graph)
+		die("cannot combine --walk-reflogs with --graph");
+
 	return left;
 }
 
-void prepare_revision_walk(struct rev_info *revs)
+static void add_child(struct rev_info *revs, struct commit *parent, struct commit *child)
+{
+	struct commit_list *l = xcalloc(1, sizeof(*l));
+
+	l->item = child;
+	l->next = add_decoration(&revs->children, &parent->object, l);
+}
+
+static int remove_duplicate_parents(struct commit *commit)
+{
+	struct commit_list **pp, *p;
+	int surviving_parents;
+
+	/* Examine existing parents while marking ones we have seen... */
+	pp = &commit->parents;
+	while ((p = *pp) != NULL) {
+		struct commit *parent = p->item;
+		if (parent->object.flags & TMP_MARK) {
+			*pp = p->next;
+			continue;
+		}
+		parent->object.flags |= TMP_MARK;
+		pp = &p->next;
+	}
+	/* count them while clearing the temporary mark */
+	surviving_parents = 0;
+	for (p = commit->parents; p; p = p->next) {
+		p->item->object.flags &= ~TMP_MARK;
+		surviving_parents++;
+	}
+	return surviving_parents;
+}
+
+struct merge_simplify_state {
+	struct commit *simplified;
+};
+
+static struct merge_simplify_state *locate_simplify_state(struct rev_info *revs, struct commit *commit)
+{
+	struct merge_simplify_state *st;
+
+	st = lookup_decoration(&revs->merge_simplification, &commit->object);
+	if (!st) {
+		st = xcalloc(1, sizeof(*st));
+		add_decoration(&revs->merge_simplification, &commit->object, st);
+	}
+	return st;
+}
+
+static struct commit_list **simplify_one(struct rev_info *revs, struct commit *commit, struct commit_list **tail)
+{
+	struct commit_list *p;
+	struct merge_simplify_state *st, *pst;
+	int cnt;
+
+	st = locate_simplify_state(revs, commit);
+
+	/*
+	 * Have we handled this one?
+	 */
+	if (st->simplified)
+		return tail;
+
+	/*
+	 * An UNINTERESTING commit simplifies to itself, so does a
+	 * root commit.  We do not rewrite parents of such commit
+	 * anyway.
+	 */
+	if ((commit->object.flags & UNINTERESTING) || !commit->parents) {
+		st->simplified = commit;
+		return tail;
+	}
+
+	/*
+	 * Do we know what commit all of our parents should be rewritten to?
+	 * Otherwise we are not ready to rewrite this one yet.
+	 */
+	for (cnt = 0, p = commit->parents; p; p = p->next) {
+		pst = locate_simplify_state(revs, p->item);
+		if (!pst->simplified) {
+			tail = &commit_list_insert(p->item, tail)->next;
+			cnt++;
+		}
+	}
+	if (cnt) {
+		tail = &commit_list_insert(commit, tail)->next;
+		return tail;
+	}
+
+	/*
+	 * Rewrite our list of parents.
+	 */
+	for (p = commit->parents; p; p = p->next) {
+		pst = locate_simplify_state(revs, p->item);
+		p->item = pst->simplified;
+	}
+	cnt = remove_duplicate_parents(commit);
+
+	/*
+	 * It is possible that we are a merge and one side branch
+	 * does not have any commit that touches the given paths;
+	 * in such a case, the immediate parents will be rewritten
+	 * to different commits.
+	 *
+	 *      o----X		X: the commit we are looking at;
+	 *     /    /		o: a commit that touches the paths;
+	 * ---o----'
+	 *
+	 * Further reduce the parents by removing redundant parents.
+	 */
+	if (1 < cnt) {
+		struct commit_list *h = reduce_heads(commit->parents);
+		cnt = commit_list_count(h);
+		free_commit_list(commit->parents);
+		commit->parents = h;
+	}
+
+	/*
+	 * A commit simplifies to itself if it is a root, if it is
+	 * UNINTERESTING, if it touches the given paths, or if it is a
+	 * merge and its parents simplifies to more than one commits
+	 * (the first two cases are already handled at the beginning of
+	 * this function).
+	 *
+	 * Otherwise, it simplifies to what its sole parent simplifies to.
+	 */
+	if (!cnt ||
+	    (commit->object.flags & UNINTERESTING) ||
+	    !(commit->object.flags & TREESAME) ||
+	    (1 < cnt))
+		st->simplified = commit;
+	else {
+		pst = locate_simplify_state(revs, commit->parents->item);
+		st->simplified = pst->simplified;
+	}
+	return tail;
+}
+
+static void simplify_merges(struct rev_info *revs)
+{
+	struct commit_list *list;
+	struct commit_list *yet_to_do, **tail;
+
+	if (!revs->topo_order)
+		sort_in_topological_order(&revs->commits, revs->lifo);
+	if (!revs->prune)
+		return;
+
+	/* feed the list reversed */
+	yet_to_do = NULL;
+	for (list = revs->commits; list; list = list->next)
+		commit_list_insert(list->item, &yet_to_do);
+	while (yet_to_do) {
+		list = yet_to_do;
+		yet_to_do = NULL;
+		tail = &yet_to_do;
+		while (list) {
+			struct commit *commit = list->item;
+			struct commit_list *next = list->next;
+			free(list);
+			list = next;
+			tail = simplify_one(revs, commit, tail);
+		}
+	}
+
+	/* clean up the result, removing the simplified ones */
+	list = revs->commits;
+	revs->commits = NULL;
+	tail = &revs->commits;
+	while (list) {
+		struct commit *commit = list->item;
+		struct commit_list *next = list->next;
+		struct merge_simplify_state *st;
+		free(list);
+		list = next;
+		st = locate_simplify_state(revs, commit);
+		if (st->simplified == commit)
+			tail = &commit_list_insert(commit, tail)->next;
+	}
+}
+
+static void set_children(struct rev_info *revs)
+{
+	struct commit_list *l;
+	for (l = revs->commits; l; l = l->next) {
+		struct commit *commit = l->item;
+		struct commit_list *p;
+
+		for (p = commit->parents; p; p = p->next)
+			add_child(revs, p->item, commit);
+	}
+}
+
+int prepare_revision_walk(struct rev_info *revs)
 {
-	sort_by_date(&revs->commits);
+	int nr = revs->pending.nr;
+	struct object_array_entry *e, *list;
+
+	e = list = revs->pending.objects;
+	revs->pending.nr = 0;
+	revs->pending.alloc = 0;
+	revs->pending.objects = NULL;
+	while (--nr >= 0) {
+		struct commit *commit = handle_commit(revs, e->item, e->name);
+		if (commit) {
+			if (!(commit->object.flags & SEEN)) {
+				commit->object.flags |= SEEN;
+				commit_list_insert_by_date(commit, &revs->commits);
+			}
+		}
+		e++;
+	}
+	free(list);
+
+	if (revs->no_walk)
+		return 0;
 	if (revs->limited)
-		limit_list(revs);
+		if (limit_list(revs) < 0)
+			return -1;
 	if (revs->topo_order)
 		sort_in_topological_order(&revs->commits, revs->lifo);
+	if (revs->simplify_merges)
+		simplify_merges(revs);
+	if (revs->children.name)
+		set_children(revs);
+	return 0;
 }
 
-static int rewrite_one(struct commit **pp)
+enum rewrite_result {
+	rewrite_one_ok,
+	rewrite_one_noparents,
+	rewrite_one_error
+};
+
+static enum rewrite_result rewrite_one(struct rev_info *revs, struct commit **pp)
 {
+	struct commit_list *cache = NULL;
+
 	for (;;) {
 		struct commit *p = *pp;
-		if (p->object.flags & (TREECHANGE | UNINTERESTING))
-			return 0;
+		if (!revs->limited)
+			if (add_parents_to_list(revs, p, &revs->commits, &cache) < 0)
+				return rewrite_one_error;
+		if (p->parents && p->parents->next)
+			return rewrite_one_ok;
+		if (p->object.flags & UNINTERESTING)
+			return rewrite_one_ok;
+		if (!(p->object.flags & TREESAME))
+			return rewrite_one_ok;
 		if (!p->parents)
-			return -1;
+			return rewrite_one_noparents;
 		*pp = p->parents->item;
 	}
 }
 
-static void rewrite_parents(struct commit *commit)
+static int rewrite_parents(struct rev_info *revs, struct commit *commit)
 {
 	struct commit_list **pp = &commit->parents;
 	while (*pp) {
 		struct commit_list *parent = *pp;
-		if (rewrite_one(&parent->item) < 0) {
+		switch (rewrite_one(revs, &parent->item)) {
+		case rewrite_one_ok:
+			break;
+		case rewrite_one_noparents:
 			*pp = parent->next;
 			continue;
+		case rewrite_one_error:
+			return -1;
 		}
 		pp = &parent->next;
 	}
+	remove_duplicate_parents(commit);
+	return 0;
 }
 
-struct commit *get_revision(struct rev_info *revs)
+static int commit_match(struct commit *commit, struct rev_info *opt)
 {
-	struct commit_list *list = revs->commits;
+	if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
+		return 1;
+	return grep_buffer(&opt->grep_filter,
+			   NULL, /* we say nothing, not even filename */
+			   commit->buffer, strlen(commit->buffer));
+}
+
+static inline int want_ancestry(struct rev_info *revs)
+{
+	return (revs->rewrite_parents || revs->children.name);
+}
 
-	if (!list)
+enum commit_action get_commit_action(struct rev_info *revs, struct commit *commit)
+{
+	if (commit->object.flags & SHOWN)
+		return commit_ignore;
+	if (revs->unpacked && has_sha1_pack(commit->object.sha1))
+		return commit_ignore;
+	if (revs->show_all)
+		return commit_show;
+	if (commit->object.flags & UNINTERESTING)
+		return commit_ignore;
+	if (revs->min_age != -1 && (commit->date > revs->min_age))
+		return commit_ignore;
+	if (revs->min_parents || (revs->max_parents >= 0)) {
+		int n = 0;
+		struct commit_list *p;
+		for (p = commit->parents; p; p = p->next)
+			n++;
+		if ((n < revs->min_parents) ||
+		    ((revs->max_parents >= 0) && (n > revs->max_parents)))
+			return commit_ignore;
+	}
+	if (!commit_match(commit, revs))
+		return commit_ignore;
+	if (revs->prune && revs->dense) {
+		/* Commit without changes? */
+		if (commit->object.flags & TREESAME) {
+			/* drop merges unless we want parenthood */
+			if (!want_ancestry(revs))
+				return commit_ignore;
+			/* non-merge - always ignore it */
+			if (!commit->parents || !commit->parents->next)
+				return commit_ignore;
+		}
+	}
+	return commit_show;
+}
+
+enum commit_action simplify_commit(struct rev_info *revs, struct commit *commit)
+{
+	enum commit_action action = get_commit_action(revs, commit);
+
+	if (action == commit_show &&
+	    !revs->show_all &&
+	    revs->prune && revs->dense && want_ancestry(revs)) {
+		if (rewrite_parents(revs, commit) < 0)
+			return commit_error;
+	}
+	return action;
+}
+
+static struct commit *get_revision_1(struct rev_info *revs)
+{
+	if (!revs->commits)
 		return NULL;
 
-	/* Check the max_count ... */
+	do {
+		struct commit_list *entry = revs->commits;
+		struct commit *commit = entry->item;
+
+		revs->commits = entry->next;
+		free(entry);
+
+		if (revs->reflog_info) {
+			fake_reflog_parent(revs->reflog_info, commit);
+			commit->object.flags &= ~(ADDED | SEEN | SHOWN);
+		}
+
+		/*
+		 * If we haven't done the list limiting, we need to look at
+		 * the parents here. We also need to do the date-based limiting
+		 * that we'd otherwise have done in limit_list().
+		 */
+		if (!revs->limited) {
+			if (revs->max_age != -1 &&
+			    (commit->date < revs->max_age))
+				continue;
+			if (add_parents_to_list(revs, commit, &revs->commits, NULL) < 0)
+				die("Failed to traverse parents of commit %s",
+				    sha1_to_hex(commit->object.sha1));
+		}
+
+		switch (simplify_commit(revs, commit)) {
+		case commit_ignore:
+			continue;
+		case commit_error:
+			die("Failed to simplify parents of commit %s",
+			    sha1_to_hex(commit->object.sha1));
+		default:
+			return commit;
+		}
+	} while (revs->commits);
+	return NULL;
+}
+
+static void gc_boundary(struct object_array *array)
+{
+	unsigned nr = array->nr;
+	unsigned alloc = array->alloc;
+	struct object_array_entry *objects = array->objects;
+
+	if (alloc <= nr) {
+		unsigned i, j;
+		for (i = j = 0; i < nr; i++) {
+			if (objects[i].item->flags & SHOWN)
+				continue;
+			if (i != j)
+				objects[j] = objects[i];
+			j++;
+		}
+		for (i = j; i < nr; i++)
+			objects[i].item = NULL;
+		array->nr = j;
+	}
+}
+
+static void create_boundary_commit_list(struct rev_info *revs)
+{
+	unsigned i;
+	struct commit *c;
+	struct object_array *array = &revs->boundary_commits;
+	struct object_array_entry *objects = array->objects;
+
+	/*
+	 * If revs->commits is non-NULL at this point, an error occurred in
+	 * get_revision_1().  Ignore the error and continue printing the
+	 * boundary commits anyway.  (This is what the code has always
+	 * done.)
+	 */
+	if (revs->commits) {
+		free_commit_list(revs->commits);
+		revs->commits = NULL;
+	}
+
+	/*
+	 * Put all of the actual boundary commits from revs->boundary_commits
+	 * into revs->commits
+	 */
+	for (i = 0; i < array->nr; i++) {
+		c = (struct commit *)(objects[i].item);
+		if (!c)
+			continue;
+		if (!(c->object.flags & CHILD_SHOWN))
+			continue;
+		if (c->object.flags & (SHOWN | BOUNDARY))
+			continue;
+		c->object.flags |= BOUNDARY;
+		commit_list_insert(c, &revs->commits);
+	}
+
+	/*
+	 * If revs->topo_order is set, sort the boundary commits
+	 * in topological order
+	 */
+	sort_in_topological_order(&revs->commits, revs->lifo);
+}
+
+static struct commit *get_revision_internal(struct rev_info *revs)
+{
+	struct commit *c = NULL;
+	struct commit_list *l;
+
+	if (revs->boundary == 2) {
+		/*
+		 * All of the normal commits have already been returned,
+		 * and we are now returning boundary commits.
+		 * create_boundary_commit_list() has populated
+		 * revs->commits with the remaining commits to return.
+		 */
+		c = pop_commit(&revs->commits);
+		if (c)
+			c->object.flags |= SHOWN;
+		return c;
+	}
+
+	/*
+	 * Now pick up what they want to give us
+	 */
+	c = get_revision_1(revs);
+	if (c) {
+		while (0 < revs->skip_count) {
+			revs->skip_count--;
+			c = get_revision_1(revs);
+			if (!c)
+				break;
+		}
+	}
+
+	/*
+	 * Check the max_count.
+	 */
 	switch (revs->max_count) {
 	case -1:
 		break;
 	case 0:
-		return NULL;
+		c = NULL;
+		break;
 	default:
 		revs->max_count--;
 	}
 
-	do {
-		struct commit *commit = revs->commits->item;
+	if (c)
+		c->object.flags |= SHOWN;
 
-		if (commit->object.flags & (UNINTERESTING|SHOWN))
-			goto next;
-		if (revs->min_age != -1 && (commit->date > revs->min_age))
-			goto next;
-		if (revs->max_age != -1 && (commit->date < revs->max_age))
-			return NULL;
-		if (revs->no_merges && commit->parents && commit->parents->next)
-			goto next;
-		if (revs->paths && revs->dense) {
-			if (!(commit->object.flags & TREECHANGE))
-				goto next;
-			rewrite_parents(commit);
-		}
-		/* More to go? */
-		if (revs->max_count)
-			pop_most_recent_commit(&revs->commits, SEEN);
-		commit->object.flags |= SHOWN;
-		return commit;
-next:
-		pop_most_recent_commit(&revs->commits, SEEN);
-	} while (revs->commits);
-	return NULL;
+	if (!revs->boundary) {
+		return c;
+	}
+
+	if (!c) {
+		/*
+		 * get_revision_1() runs out the commits, and
+		 * we are done computing the boundaries.
+		 * switch to boundary commits output mode.
+		 */
+		revs->boundary = 2;
+
+		/*
+		 * Update revs->commits to contain the list of
+		 * boundary commits.
+		 */
+		create_boundary_commit_list(revs);
+
+		return get_revision_internal(revs);
+	}
+
+	/*
+	 * boundary commits are the commits that are parents of the
+	 * ones we got from get_revision_1() but they themselves are
+	 * not returned from get_revision_1().  Before returning
+	 * 'c', we need to mark its parents that they could be boundaries.
+	 */
+
+	for (l = c->parents; l; l = l->next) {
+		struct object *p;
+		p = &(l->item->object);
+		if (p->flags & (CHILD_SHOWN | SHOWN))
+			continue;
+		p->flags |= CHILD_SHOWN;
+		gc_boundary(&revs->boundary_commits);
+		add_object_array(p, NULL, &revs->boundary_commits);
+	}
+
+	return c;
+}
+
+struct commit *get_revision(struct rev_info *revs)
+{
+	struct commit *c;
+	struct commit_list *reversed;
+
+	if (revs->reverse) {
+		reversed = NULL;
+		while ((c = get_revision_internal(revs))) {
+			commit_list_insert(c, &reversed);
+		}
+		revs->commits = reversed;
+		revs->reverse = 0;
+		revs->reverse_output_stage = 1;
+	}
+
+	if (revs->reverse_output_stage)
+		return pop_commit(&revs->commits);
+
+	c = get_revision_internal(revs);
+	if (c && revs->graph)
+		graph_update(revs->graph, c);
+	return c;
+}
+
+char *get_revision_mark(const struct rev_info *revs, const struct commit *commit)
+{
+	if (commit->object.flags & BOUNDARY)
+		return "-";
+	else if (commit->object.flags & UNINTERESTING)
+		return "^";
+	else if (commit->object.flags & PATCHSAME)
+		return "=";
+	else if (!revs || revs->left_right) {
+		if (commit->object.flags & SYMMETRIC_LEFT)
+			return "<";
+		else
+			return ">";
+	} else if (revs->graph)
+		return "*";
+	else if (revs->cherry_mark)
+		return "+";
+	return "";
+}
+
+void put_revision_mark(const struct rev_info *revs, const struct commit *commit)
+{
+	char *mark = get_revision_mark(revs, commit);
+	if (!strlen(mark))
+		return;
+	fputs(mark, stdout);
+	putchar(' ');
 }