X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=revision.c;h=113dd5a89fc03ff17b04443f2ac7148b4c36af33;hb=81f3a188a3781fa4a818ed27ee83430682a98ec4;hp=d61410bc59bd6698d1aba4deb37faf75b31e3242;hpb=b5233a61955772b4430abb0eb1d03b7fbdd33e6a;p=git.git

diff --git a/revision.c b/revision.c
index d61410bc..113dd5a8 100644
--- a/revision.c
+++ b/revision.c
@@ -3,6 +3,7 @@
 #include "blob.h"
 #include "tree.h"
 #include "commit.h"
+#include "diff.h"
 #include "refs.h"
 #include "revision.h"
 
@@ -81,18 +82,20 @@ void mark_parents_uninteresting(struct commit *commit)
 
 	while (parents) {
 		struct commit *commit = parents->item;
-		commit->object.flags |= UNINTERESTING;
+		if (!(commit->object.flags & UNINTERESTING)) {
+			commit->object.flags |= UNINTERESTING;
 
-		/*
-		 * Normally we haven't parsed the parent
-		 * yet, so we won't have a parent of a parent
-		 * here. However, it may turn out that we've
-		 * reached this commit some other way (where it
-		 * wasn't uninteresting), in which case we need
-		 * to mark its parents recursively too..
-		 */
-		if (commit->parents)
-			mark_parents_uninteresting(commit);
+			/*
+			 * Normally we haven't parsed the parent
+			 * yet, so we won't have a parent of a parent
+			 * here. However, it may turn out that we've
+			 * reached this commit some other way (where it
+			 * wasn't uninteresting), in which case we need
+			 * to mark its parents recursively too..
+			 */
+			if (commit->parents)
+				mark_parents_uninteresting(commit);
+		}
 
 		/*
 		 * A missing commit is ok iff its parent is marked
@@ -113,21 +116,27 @@ static void add_pending_object(struct rev_info *revs, struct object *obj, const
 	add_object(obj, &revs->pending_objects, NULL, name);
 }
 
-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)
 		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) {
 		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);
 		object = parse_object(tag->tagged->sha1);
 		if (!object)
@@ -140,11 +149,13 @@ static struct commit *get_commit_reference(struct rev_info *revs, const char *na
 	 */
 	if (object->type == commit_type) {
 		struct commit *commit = (struct commit *)object;
-		object->flags |= flags;
 		if (parse_commit(commit) < 0)
 			die("unable to parse commit %s", name);
-		if (flags & UNINTERESTING)
+		if (flags & UNINTERESTING) {
+			commit->object.flags |= UNINTERESTING;
 			mark_parents_uninteresting(commit);
+			revs->limited = 1;
+		}
 		return commit;
 	}
 
@@ -181,12 +192,272 @@ static struct commit *get_commit_reference(struct rev_info *revs, const char *na
 	die("%s is unknown object", name);
 }
 
-static void add_one_commit(struct commit *commit, struct rev_info *revs)
+static int everybody_uninteresting(struct commit_list *orig)
+{
+	struct commit_list *list = orig;
+	while (list) {
+		struct commit *commit = list->item;
+		list = list->next;
+		if (commit->object.flags & UNINTERESTING)
+			continue;
+		return 0;
+	}
+	return 1;
+}
+
+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)
+{
+	int diff = REV_TREE_DIFFERENT;
+
+	/*
+	 * Is it an add of a new file? It means that the old tree
+	 * didn't have it at all, so we will turn "REV_TREE_SAME" ->
+	 * "REV_TREE_NEW", but leave any "REV_TREE_DIFFERENT" alone
+	 * (and if it already was "REV_TREE_NEW", we'll keep it
+	 * "REV_TREE_NEW" of course).
+	 */
+	if (addremove == '+') {
+		diff = tree_difference;
+		if (diff != REV_TREE_SAME)
+			return;
+		diff = REV_TREE_NEW;
+	}
+	tree_difference = diff;
+}
+
+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)
+{
+	tree_difference = REV_TREE_DIFFERENT;
+}
+
+int rev_compare_tree(struct rev_info *revs, struct tree *t1, struct tree *t2)
+{
+	if (!t1)
+		return REV_TREE_NEW;
+	if (!t2)
+		return REV_TREE_DIFFERENT;
+	tree_difference = REV_TREE_SAME;
+	if (diff_tree_sha1(t1->object.sha1, t2->object.sha1, "",
+			   &revs->pruning) < 0)
+		return REV_TREE_DIFFERENT;
+	return tree_difference;
+}
+
+int rev_same_tree_as_empty(struct rev_info *revs, struct tree *t1)
 {
-	if (!commit || (commit->object.flags & SEEN))
+	int retval;
+	void *tree;
+	struct tree_desc empty, real;
+
+	if (!t1)
+		return 0;
+
+	tree = read_object_with_reference(t1->object.sha1, tree_type, &real.size, NULL);
+	if (!tree)
+		return 0;
+	real.buf = tree;
+
+	empty.buf = "";
+	empty.size = 0;
+
+	tree_difference = 0;
+	retval = diff_tree(&empty, &real, "", &revs->pruning);
+	free(tree);
+
+	return retval >= 0 && !tree_difference;
+}
+
+static void try_to_simplify_commit(struct rev_info *revs, struct commit *commit)
+{
+	struct commit_list **pp, *parent;
+	int tree_changed = 0;
+
+	if (!commit->tree)
+		return;
+
+	if (!commit->parents) {
+		if (!rev_same_tree_as_empty(revs, commit->tree))
+			commit->object.flags |= TREECHANGE;
 		return;
-	commit->object.flags |= SEEN;
-	commit_list_insert(commit, &revs->commits);
+	}
+
+	pp = &commit->parents;
+	while ((parent = *pp) != NULL) {
+		struct commit *p = parent->item;
+
+		parse_commit(p);
+		switch (rev_compare_tree(revs, p->tree, commit->tree)) {
+		case REV_TREE_SAME:
+			if (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
+				 * to lose the other branches of this
+				 * merge, so we just keep going.
+				 */
+				pp = &parent->next;
+				continue;
+			}
+			parent->next = NULL;
+			commit->parents = parent;
+			return;
+
+		case REV_TREE_NEW:
+			if (revs->remove_empty_trees &&
+			    rev_same_tree_as_empty(revs, p->tree)) {
+				/* 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.
+				 */
+				parse_commit(p);
+				p->parents = NULL;
+			}
+		/* fallthrough */
+		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;
+}
+
+static void add_parents_to_list(struct rev_info *revs, struct commit *commit, struct commit_list **list)
+{
+	struct commit_list *parent = commit->parents;
+
+	if (commit->object.flags & ADDED)
+		return;
+	commit->object.flags |= ADDED;
+
+	/*
+	 * If the commit is uninteresting, don't try to
+	 * prune parents - we want the maximal uninteresting
+	 * set.
+	 *
+	 * Normally we haven't parsed the parent
+	 * yet, so we won't have a parent of a parent
+	 * here. However, it may turn out that we've
+	 * reached this commit some other way (where it
+	 * wasn't uninteresting), in which case we need
+	 * to mark its parents recursively too..
+	 */
+	if (commit->object.flags & UNINTERESTING) {
+		while (parent) {
+			struct commit *p = parent->item;
+			parent = parent->next;
+			parse_commit(p);
+			p->object.flags |= UNINTERESTING;
+			if (p->parents)
+				mark_parents_uninteresting(p);
+			if (p->object.flags & SEEN)
+				continue;
+			p->object.flags |= SEEN;
+			insert_by_date(p, list);
+		}
+		return;
+	}
+
+	/*
+	 * Ok, the commit wasn't uninteresting. Try to
+	 * simplify the commit history and find the parent
+	 * that has no differences in the path set if one exists.
+	 */
+	if (revs->prune_fn)
+		revs->prune_fn(revs, commit);
+
+	if (revs->no_walk)
+		return;
+
+	parent = commit->parents;
+	while (parent) {
+		struct commit *p = parent->item;
+
+		parent = parent->next;
+
+		parse_commit(p);
+		if (p->object.flags & SEEN)
+			continue;
+		p->object.flags |= SEEN;
+		insert_by_date(p, list);
+	}
+}
+
+static void limit_list(struct rev_info *revs)
+{
+	struct commit_list *list = revs->commits;
+	struct commit_list *newlist = NULL;
+	struct commit_list **p = &newlist;
+
+	while (list) {
+		struct commit_list *entry = list;
+		struct commit *commit = list->item;
+		struct object *obj = &commit->object;
+
+		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 (obj->flags & UNINTERESTING) {
+			mark_parents_uninteresting(commit);
+			if (everybody_uninteresting(list))
+				break;
+			continue;
+		}
+		if (revs->min_age != -1 && (commit->date > revs->min_age))
+			continue;
+		p = &commit_list_insert(commit, p)->next;
+	}
+	if (revs->boundary) {
+		/* mark the ones that are on the result list first */
+		for (list = newlist; list; list = list->next) {
+			struct commit *commit = list->item;
+			commit->object.flags |= TMP_MARK;
+		}
+		for (list = newlist; list; list = list->next) {
+			struct commit *commit = list->item;
+			struct object *obj = &commit->object;
+			struct commit_list *parent;
+			if (obj->flags & UNINTERESTING)
+				continue;
+			for (parent = commit->parents;
+			     parent;
+			     parent = parent->next) {
+				struct commit *pcommit = parent->item;
+				if (!(pcommit->object.flags & UNINTERESTING))
+					continue;
+				pcommit->object.flags |= BOUNDARY;
+				if (pcommit->object.flags & TMP_MARK)
+					continue;
+				pcommit->object.flags |= TMP_MARK;
+				p = &commit_list_insert(pcommit, p)->next;
+			}
+		}
+		for (list = newlist; list; list = list->next) {
+			struct commit *commit = list->item;
+			commit->object.flags &= ~TMP_MARK;
+		}
+	}
+	revs->commits = newlist;
 }
 
 static int all_flags;
@@ -194,8 +465,8 @@ static struct rev_info *all_revs;
 
 static int handle_one_ref(const char *path, const unsigned char *sha1)
 {
-	struct commit *commit = get_commit_reference(all_revs, path, sha1, all_flags);
-	add_one_commit(commit, all_revs);
+	struct object *object = get_reference(all_revs, path, sha1, all_flags);
+	add_pending_object(all_revs, object, "");
 	return 0;
 }
 
@@ -206,20 +477,15 @@ static void handle_all(struct rev_info *revs, unsigned flags)
 	for_each_ref(handle_one_ref);
 }
 
-/*
- * Parse revision information, filling in the "rev_info" structure,
- * and removing the used arguments from the argument list.
- *
- * Returns the number of arguments left ("new argc").
- */
-int setup_revisions(int argc, const char **argv, struct rev_info *revs)
+void init_revisions(struct rev_info *revs)
 {
-	int i, flags, seen_dashdash;
-	const char *def = NULL;
-	const char **unrecognized = argv+1;
-	int left = 1;
-
 	memset(revs, 0, sizeof(*revs));
+
+	revs->abbrev = DEFAULT_ABBREV;
+	revs->ignore_merges = 1;
+	revs->pruning.recursive = 1;
+	revs->pruning.add_remove = file_add_remove;
+	revs->pruning.change = file_change;
 	revs->lifo = 1;
 	revs->dense = 1;
 	revs->prefix = setup_git_directory();
@@ -227,6 +493,30 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 	revs->min_age = -1;
 	revs->max_count = -1;
 
+	revs->prune_fn = NULL;
+	revs->prune_data = NULL;
+
+	revs->topo_setter = topo_sort_default_setter;
+	revs->topo_getter = topo_sort_default_getter;
+
+	revs->commit_format = CMIT_FMT_DEFAULT;
+
+	diff_setup(&revs->diffopt);
+}
+
+/*
+ * Parse revision information, filling in the "rev_info" structure,
+ * and removing the used arguments from the argument list.
+ *
+ * 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 i, flags, seen_dashdash;
+	const char **unrecognized = argv + 1;
+	int left = 1;
+
 	/* First, search for "--" */
 	seen_dashdash = 0;
 	for (i = 1; i < argc; i++) {
@@ -235,32 +525,64 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 			continue;
 		argv[i] = NULL;
 		argc = i;
-		revs->paths = get_pathspec(revs->prefix, argv + i + 1);
+		revs->prune_data = get_pathspec(revs->prefix, argv + i + 1);
 		seen_dashdash = 1;
 		break;
 	}
 
 	flags = 0;
 	for (i = 1; i < argc; i++) {
-		struct commit *commit;
+		struct object *object;
 		const char *arg = argv[i];
 		unsigned char sha1[20];
 		char *dotdot;
 		int local_flags;
 
 		if (*arg == '-') {
+			int opts;
 			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);
 				continue;
 			}
+			if (!strncmp(arg, "--since=", 8)) {
+				revs->max_age = approxidate(arg + 8);
+				continue;
+			}
+			if (!strncmp(arg, "--after=", 8)) {
+				revs->max_age = approxidate(arg + 8);
+				continue;
+			}
 			if (!strncmp(arg, "--min-age=", 10)) {
 				revs->min_age = atoi(arg + 10);
 				continue;
 			}
+			if (!strncmp(arg, "--before=", 9)) {
+				revs->min_age = approxidate(arg + 9);
+				continue;
+			}
+			if (!strncmp(arg, "--until=", 8)) {
+				revs->min_age = approxidate(arg + 8);
+				continue;
+			}
 			if (!strcmp(arg, "--all")) {
 				handle_all(revs, flags);
 				continue;
@@ -284,6 +606,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 				revs->topo_order = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--parents")) {
+				revs->parents = 1;
+				continue;
+			}
 			if (!strcmp(arg, "--dense")) {
 				revs->dense = 1;
 				continue;
@@ -296,6 +622,14 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 				revs->remove_empty_trees = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--no-merges")) {
+				revs->no_merges = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--boundary")) {
+				revs->boundary = 1;
+				continue;
+			}
 			if (!strcmp(arg, "--objects")) {
 				revs->tag_objects = 1;
 				revs->tree_objects = 1;
@@ -309,6 +643,80 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 				revs->edge_hint = 1;
 				continue;
 			}
+			if (!strcmp(arg, "--unpacked")) {
+				revs->unpacked = 1;
+				continue;
+			}
+			if (!strcmp(arg, "-r")) {
+				revs->diff = 1;
+				revs->diffopt.recursive = 1;
+				continue;
+			}
+			if (!strcmp(arg, "-t")) {
+				revs->diff = 1;
+				revs->diffopt.recursive = 1;
+				revs->diffopt.tree_in_recursive = 1;
+				continue;
+			}
+			if (!strcmp(arg, "-m")) {
+				revs->ignore_merges = 0;
+				continue;
+			}
+			if (!strcmp(arg, "-c")) {
+				revs->diff = 1;
+				revs->combine_merges = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--cc")) {
+				revs->diff = 1;
+				revs->dense_combined_merges = 1;
+				revs->combine_merges = 1;
+				continue;
+			}
+			if (!strcmp(arg, "-v")) {
+				revs->verbose_header = 1;
+				continue;
+			}
+			if (!strncmp(arg, "--pretty", 8)) {
+				revs->verbose_header = 1;
+				revs->commit_format = get_commit_format(arg+8);
+				continue;
+			}
+			if (!strcmp(arg, "--root")) {
+				revs->show_root_diff = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--no-commit-id")) {
+				revs->no_commit_id = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--always")) {
+				revs->always_show_header = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--no-abbrev")) {
+				revs->abbrev = 0;
+				continue;
+			}
+			if (!strcmp(arg, "--abbrev")) {
+				revs->abbrev = DEFAULT_ABBREV;
+				continue;
+			}
+			if (!strcmp(arg, "--abbrev-commit")) {
+				revs->abbrev_commit = 1;
+				continue;
+			}
+			if (!strcmp(arg, "--full-diff")) {
+				revs->diff = 1;
+				revs->full_diff = 1;
+				continue;
+			}
+			opts = diff_opt_parse(&revs->diffopt, argv+i, argc-i);
+			if (opts > 0) {
+				revs->diff = 1;
+				i += opts - 1;
+				continue;
+			}
 			*unrecognized++ = arg;
 			left++;
 			continue;
@@ -316,20 +724,24 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 		dotdot = strstr(arg, "..");
 		if (dotdot) {
 			unsigned char from_sha1[20];
-			char *next = dotdot + 2;
+			const char *next = dotdot + 2;
+			const char *this = arg;
 			*dotdot = 0;
 			if (!*next)
 				next = "HEAD";
-			if (!get_sha1(arg, from_sha1) && !get_sha1(next, sha1)) {
-				struct commit *exclude;
-				struct commit *include;
+			if (dotdot == arg)
+				this = "HEAD";
+			if (!get_sha1(this, from_sha1) &&
+			    !get_sha1(next, sha1)) {
+				struct object *exclude;
+				struct object *include;
 
-				exclude = get_commit_reference(revs, arg, from_sha1, flags ^ UNINTERESTING);
-				include = get_commit_reference(revs, next, sha1, flags);
+				exclude = get_reference(revs, this, from_sha1, flags ^ UNINTERESTING);
+				include = get_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);
+				add_pending_object(revs, exclude, this);
+				add_pending_object(revs, include, next);
 				continue;
 			}
 			*dotdot = '.';
@@ -349,22 +761,175 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs)
 			/* 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));
+					die("'%s': %s", argv[j], strerror(errno));
 			}
-			revs->paths = get_pathspec(revs->prefix, argv + i);
+			revs->prune_data = get_pathspec(revs->prefix, argv + i);
 			break;
 		}
-		commit = get_commit_reference(revs, arg, sha1, flags ^ local_flags);
-		add_one_commit(commit, revs);
+		object = get_reference(revs, arg, sha1, flags ^ local_flags);
+		add_pending_object(revs, object, arg);
 	}
-	if (def && !revs->commits) {
+	if (def && !revs->pending_objects) {
 		unsigned char sha1[20];
-		struct commit *commit;
+		struct object *object;
 		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);
+		object = get_reference(revs, def, sha1, 0);
+		add_pending_object(revs, object, def);
 	}
-	*unrecognized = NULL;
+
+	if (revs->topo_order || revs->unpacked)
+		revs->limited = 1;
+
+	if (revs->prune_data) {
+		diff_tree_setup_paths(revs->prune_data, &revs->pruning);
+		revs->prune_fn = try_to_simplify_commit;
+		if (!revs->full_diff)
+			diff_tree_setup_paths(revs->prune_data, &revs->diffopt);
+	}
+	if (revs->combine_merges) {
+		revs->ignore_merges = 0;
+		if (revs->dense_combined_merges)
+			revs->diffopt.output_format = DIFF_FORMAT_PATCH;
+	}
+	revs->diffopt.abbrev = revs->abbrev;
+	diff_setup_done(&revs->diffopt);
+
 	return left;
 }
+
+void prepare_revision_walk(struct rev_info *revs)
+{
+	struct object_list *list;
+
+	list = revs->pending_objects;
+	revs->pending_objects = NULL;
+	while (list) {
+		struct commit *commit = handle_commit(revs, list->item, list->name);
+		if (commit) {
+			if (!(commit->object.flags & SEEN)) {
+				commit->object.flags |= SEEN;
+				insert_by_date(commit, &revs->commits);
+			}
+		}
+		list = list->next;
+	}
+
+	if (revs->no_walk)
+		return;
+	if (revs->limited)
+		limit_list(revs);
+	if (revs->topo_order)
+		sort_in_topological_order_fn(&revs->commits, revs->lifo,
+					     revs->topo_setter,
+					     revs->topo_getter);
+}
+
+static int rewrite_one(struct rev_info *revs, struct commit **pp)
+{
+	for (;;) {
+		struct commit *p = *pp;
+		if (!revs->limited)
+			add_parents_to_list(revs, p, &revs->commits);
+		if (p->object.flags & (TREECHANGE | UNINTERESTING))
+			return 0;
+		if (!p->parents)
+			return -1;
+		*pp = p->parents->item;
+	}
+}
+
+static void 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(revs, &parent->item) < 0) {
+			*pp = parent->next;
+			continue;
+		}
+		pp = &parent->next;
+	}
+}
+
+static void mark_boundary_to_show(struct commit *commit)
+{
+	struct commit_list *p = commit->parents;
+	while (p) {
+		commit = p->item;
+		p = p->next;
+		if (commit->object.flags & BOUNDARY)
+			commit->object.flags |= BOUNDARY_SHOW;
+	}
+}
+
+struct commit *get_revision(struct rev_info *revs)
+{
+	struct commit_list *list = revs->commits;
+
+	if (!list)
+		return NULL;
+
+	/* Check the max_count ... */
+	switch (revs->max_count) {
+	case -1:
+		break;
+	case 0:
+		return NULL;
+	default:
+		revs->max_count--;
+	}
+
+	do {
+		struct commit *commit = revs->commits->item;
+
+		revs->commits = revs->commits->next;
+
+		/*
+		 * 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->unpacked &&
+			     has_sha1_pack(commit->object.sha1)) ||
+			    (revs->max_age != -1 &&
+			     (commit->date < revs->max_age)))
+				continue;
+			add_parents_to_list(revs, commit, &revs->commits);
+		}
+		if (commit->object.flags & SHOWN)
+			continue;
+
+		/* We want to show boundary commits only when their
+		 * children are shown.  When path-limiter is in effect,
+		 * rewrite_parents() drops some commits from getting shown,
+		 * and there is no point showing boundary parents that
+		 * are not shown.  After rewrite_parents() rewrites the
+		 * parents of a commit that is shown, we mark the boundary
+		 * parents with BOUNDARY_SHOW.
+		 */
+		if (commit->object.flags & BOUNDARY_SHOW) {
+			commit->object.flags |= SHOWN;
+			return commit;
+		}
+		if (commit->object.flags & UNINTERESTING)
+			continue;
+		if (revs->min_age != -1 && (commit->date > revs->min_age))
+			continue;
+		if (revs->no_merges &&
+		    commit->parents && commit->parents->next)
+			continue;
+		if (revs->prune_fn && revs->dense) {
+			if (!(commit->object.flags & TREECHANGE))
+				continue;
+			if (revs->parents)
+				rewrite_parents(revs, commit);
+		}
+		if (revs->boundary)
+			mark_boundary_to_show(commit);
+		commit->object.flags |= SHOWN;
+		return commit;
+	} while (revs->commits);
+	return NULL;
+}