combine_notes_cat_sort_uniq(): sort and dedup lines all at once

Instead of reading lines one by one and insertion-sorting them into a
string_list, read all of the lines, sort them, then remove duplicates.
Aside from being less code, this reduces the complexity from O(N^2) to
O(N lg N) in the total number of lines.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Acked-by: Johan Herland <johan@herland.net>
Signed-off-by: Jeff King <peff@peff.net>

diff --git a/notes.c b/notes.c
index 8652f8fcf384a1d981a9d9714f46db40308c2112..62f8f6f75bf23bf0502cec508f0079255a5db2b2 100644 (file)
--- a/notes.c
+++ b/notes.c
@@ -848,15 +848,16 @@ int combine_notes_ignore(unsigned char *cur_sha1,
        return 0;
 }
 
-static int string_list_add_note_lines(struct string_list *sort_uniq_list,
+/*
+ * Add the lines from the named object to list, with trailing
+ * newlines removed.
+ */
+static int string_list_add_note_lines(struct string_list *list,
                                      const unsigned char *sha1)
 {
        char *data;
        unsigned long len;
        enum object_type t;
-       struct strbuf buf = STRBUF_INIT;
-       struct strbuf **lines = NULL;
-       int i, list_index;
 
        if (is_null_sha1(sha1))
                return 0;
@@ -868,24 +869,14 @@ static int string_list_add_note_lines(struct string_list *sort_uniq_list,
                return t != OBJ_BLOB || !data;
        }
 
-       strbuf_attach(&buf, data, len, len + 1);
-       lines = strbuf_split(&buf, '\n');
-
-       for (i = 0; lines[i]; i++) {
-               if (lines[i]->buf[lines[i]->len - 1] == '\n')
-                       strbuf_setlen(lines[i], lines[i]->len - 1);
-               if (!lines[i]->len)
-                       continue; /* skip empty lines */
-               list_index = string_list_find_insert_index(sort_uniq_list,
-                                                          lines[i]->buf, 0);
-               if (list_index < 0)
-                       continue; /* skip duplicate lines */
-               string_list_insert_at_index(sort_uniq_list, list_index,
-                                           lines[i]->buf);
-       }
-
-       strbuf_list_free(lines);
-       strbuf_release(&buf);
+       /*
+        * If the last line of the file is EOL-terminated, this will
+        * add an empty string to the list.  But it will be removed
+        * later, along with any empty strings that came from empty
+        * lines within the file.
+        */
+       string_list_split(list, data, '\n', -1);
+       free(data);
        return 0;
 }
 
@@ -910,6 +901,9 @@ int combine_notes_cat_sort_uniq(unsigned char *cur_sha1,
                goto out;
        if (string_list_add_note_lines(&sort_uniq_list, new_sha1))
                goto out;
+       string_list_remove_empty_items(&sort_uniq_list, 0);
+       sort_string_list(&sort_uniq_list);
+       string_list_remove_duplicates(&sort_uniq_list, 0);
 
        /* create a new blob object from sort_uniq_list */
        if (for_each_string_list(&sort_uniq_list,