topo-order: make --date-order optional.

This adds --date-order to rev-list; it is similar to topo order
in the sense that no parent comes before all of its children,
but otherwise things are still ordered in the commit timestamp
order.

The same flag is also added to show-branch.

Signed-off-by: Junio C Hamano <junkio@cox.net>

commit.c

@@ -571,7 +571,7 @@ int count_parents(struct commit * commit)
 /*
  * Performs an in-place topological sort on the list supplied.
  */
-void sort_in_topological_order(struct commit_list ** list)
+void sort_in_topological_order(struct commit_list ** list, int lifo)
 {
 	struct commit_list * next = *list;
 	struct commit_list * work = NULL, **insert;
@@ -630,7 +630,10 @@ void sort_in_topological_order(struct commit_list ** list)
 		}
 		next=next->next;
 	}
+
 	/* process the list in topological order */
+	if (!lifo)
+		sort_by_date(&work);
 	while (work) {
 		struct commit * work_item = pop_commit(&work);
 		struct sort_node * work_node = (struct sort_node *)work_item->object.util;
@@ -647,8 +650,12 @@ void sort_in_topological_order(struct commit_list ** list)
                                  * guaranteeing topological order.
                                  */
 				pn->indegree--;
-				if (!pn->indegree) 
-					commit_list_insert(parent, &work);
+				if (!pn->indegree) {
+					if (!lifo)
+						insert_by_date(parent, &work);
+					else
+						commit_list_insert(parent, &work);
+				}
 			}
 			parents=parents->next;
 		}

commit.h

@@ -72,6 +72,8 @@ int count_parents(struct commit * commit);
  * Post-conditions: 
  *   invariant of resulting list is:
  *      a reachable from b => ord(b) < ord(a)
+ *   in addition, when lifo == 0, commits on parallel tracks are
+ *   sorted in the dates order.
  */
-void sort_in_topological_order(struct commit_list ** list);
+void sort_in_topological_order(struct commit_list ** list, int lifo);
 #endif /* COMMIT_H */

rev-list.c

@@ -27,6 +27,7 @@ static const char rev_list_usage[] =
 "  ordering output:\n"
 "    --merge-order [ --show-breaks ]\n"
 "    --topo-order\n"
+"    --date-order\n"
 "  formatting output:\n"
 "    --parents\n"
 "    --objects\n"
@@ -56,6 +57,7 @@ static int merge_order = 0;
 static int show_breaks = 0;
 static int stop_traversal = 0;
 static int topo_order = 0;
+static int lifo = 1;
 static int no_merges = 0;
 static const char **paths = NULL;
 static int remove_empty_trees = 0;
@@ -856,6 +858,13 @@ int main(int argc, const char **argv)
 		}
 		if (!strcmp(arg, "--topo-order")) {
 		        topo_order = 1;
+			lifo = 1;
+		        limited = 1;
+			continue;
+		}
+		if (!strcmp(arg, "--date-order")) {
+		        topo_order = 1;
+			lifo = 0;
 		        limited = 1;
 			continue;
 		}
@@ -940,7 +949,7 @@ int main(int argc, const char **argv)
 	        if (limited)
 			list = limit_list(list);
 		if (topo_order)
-			sort_in_topological_order(&list);
+			sort_in_topological_order(&list, lifo);
 		show_commit_list(list);
 	} else {
 #ifndef NO_OPENSSL

rev-parse.c

@@ -48,6 +48,7 @@ static int is_rev_argument(const char *arg)
 		"--show-breaks",
 		"--sparse",
 		"--topo-order",
+		"--date-order",
 		"--unpacked",
 		NULL
 	};

show-branch.c

@@ -535,6 +535,7 @@ int main(int ac, char **av)
 	int num_rev, i, extra = 0;
 	int all_heads = 0, all_tags = 0;
 	int all_mask, all_revs;
+	int lifo = 1;
 	char head_path[128];
 	const char *head_path_p;
 	int head_path_len;
@@ -544,7 +545,6 @@ int main(int ac, char **av)
 	int no_name = 0;
 	int sha1_name = 0;
 	int shown_merge_point = 0;
-	int topo_order = 0;
 	int with_current_branch = 0;
 	int head_at = -1;
 
@@ -586,7 +586,9 @@ int main(int ac, char **av)
 		else if (!strcmp(arg, "--independent"))
 			independent = 1;
 		else if (!strcmp(arg, "--topo-order"))
-			topo_order = 1;
+			lifo = 1;
+		else if (!strcmp(arg, "--date-order"))
+			lifo = 0;
 		else
 			usage(show_branch_usage);
 		ac--; av++;
@@ -710,8 +712,7 @@ int main(int ac, char **av)
 		exit(0);
 
 	/* Sort topologically */
-	if (topo_order)
-		sort_in_topological_order(&seen);
+	sort_in_topological_order(&seen, lifo);
 
 	/* Give names to commits */
 	if (!sha1_name && !no_name)