They can all be called with a NULL graph argument, in which case no graph
output will be printed.
-* `graph_show_commit()` calls `graph_next_line()` until it returns non-zero.
- This prints all graph lines up to, and including, the line containing this
- commit. Output is printed to stdout. The last line printed does not contain
- a terminating newline. This should not be called if the commit line has
- already been printed, or it will loop forever.
+* `graph_show_commit()` calls `graph_next_line()` and
+ `graph_is_commit_finished()` until one of them return non-zero. This prints
+ all graph lines up to, and including, the line containing this commit.
+ Output is printed to stdout. The last line printed does not contain a
+ terminating newline.
* `graph_show_oneline()` calls `graph_next_line()` and prints the result to
stdout. The line printed does not contain a terminating newline.