shortlog: optimize out useless string list

If we are in "--summary" mode, then we do not care about the
actual list of subject onelines associated with each author.
We care only about the number. So rather than store a
string-list for each author full of "<none>", let's just
keep a count.

This drops my best-of-five for "git shortlog -ns HEAD" on
linux.git from:

real    0m5.194s
user    0m5.028s
sys     0m0.168s

to:

real    0m5.057s
user    0m4.916s
sys     0m0.144s

That's about 2.5%.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/shortlog.c b/builtin/shortlog.c
index a7708c3a333d2266fab5bdeec3b2b04baa3003af..adbf1fd99150a1e18dd1d2ad142279c455b5cc80 100644 (file)
--- a/builtin/shortlog.c
+++ b/builtin/shortlog.c
@@ -14,7 +14,26 @@ static char const * const shortlog_usage[] = {
        NULL
 };
 
        NULL
 };
 

-static int compare_by_number(const void *a1, const void *a2)
+/*
+ * The util field of our string_list_items will contain one of two things:
+ *
+ *   - if --summary is not in use, it will point to a string list of the
+ *     oneline subjects assigned to this author
+ *
+ *   - if --summary is in use, we don't need that list; we only need to know
+ *     its size. So we abuse the pointer slot to store our integer counter.
+ *
+ *  This macro accesses the latter.
+ */
+#define UTIL_TO_INT(x) ((intptr_t)(x)->util)
+
+static int compare_by_counter(const void *a1, const void *a2)
+{
+       const struct string_list_item *i1 = a1, *i2 = a2;
+       return UTIL_TO_INT(i2) - UTIL_TO_INT(i1);
+}
+
+static int compare_by_list(const void *a1, const void *a2)

 {
        const struct string_list_item *i1 = a1, *i2 = a2;
        const struct string_list *l1 = i1->util, *l2 = i2->util;
 {
        const struct string_list_item *i1 = a1, *i2 = a2;
        const struct string_list *l1 = i1->util, *l2 = i2->util;


@@ -52,11 +71,9 @@ static void insert_one_record(struct shortlog *log,
                strbuf_addf(&namemailbuf, " <%.*s>", (int)maillen, mailbuf);
 
        item = string_list_insert(&log->list, namemailbuf.buf);
                strbuf_addf(&namemailbuf, " <%.*s>", (int)maillen, mailbuf);
 
        item = string_list_insert(&log->list, namemailbuf.buf);

-       if (item->util == NULL)
-               item->util = xcalloc(1, sizeof(struct string_list));

 
        if (log->summary)
 
        if (log->summary)

-               string_list_append(item->util, xstrdup(""));
+               item->util = (void *)(UTIL_TO_INT(item) + 1);

        else {
                const char *dot3 = log->common_repo_prefix;
                char *buffer, *p;
        else {
                const char *dot3 = log->common_repo_prefix;
                char *buffer, *p;


@@ -90,6 +107,8 @@ static void insert_one_record(struct shortlog *log,
                        }
                }
 
                        }
                }
 

+               if (item->util == NULL)
+                       item->util = xcalloc(1, sizeof(struct string_list));

                string_list_append(item->util, buffer);
        }
 }
                string_list_append(item->util, buffer);
        }
 }


@@ -295,14 +314,14 @@ void shortlog_output(struct shortlog *log)
 
        if (log->sort_by_number)
                qsort(log->list.items, log->list.nr, sizeof(struct string_list_item),
 
        if (log->sort_by_number)
                qsort(log->list.items, log->list.nr, sizeof(struct string_list_item),

-                       compare_by_number);
+                     log->summary ? compare_by_counter : compare_by_list);

        for (i = 0; i < log->list.nr; i++) {
        for (i = 0; i < log->list.nr; i++) {

-               struct string_list *onelines = log->list.items[i].util;
-
+               const struct string_list_item *item = &log->list.items[i];

                if (log->summary) {
                if (log->summary) {

-                       printf("%6d\t%s\n", onelines->nr, log->list.items[i].string);
+                       printf("%6d\t%s\n", (int)UTIL_TO_INT(item), item->string);

                } else {
                } else {

-                       printf("%s (%d):\n", log->list.items[i].string, onelines->nr);
+                       struct string_list *onelines = item->util;
+                       printf("%s (%d):\n", item->string, onelines->nr);

                        for (j = onelines->nr - 1; j >= 0; j--) {
                                const char *msg = onelines->items[j].string;
 
                        for (j = onelines->nr - 1; j >= 0; j--) {
                                const char *msg = onelines->items[j].string;
 


@@ -315,11 +334,11 @@ void shortlog_output(struct shortlog *log)
                                        printf("      %s\n", msg);
                        }
                        putchar('\n');
                                        printf("      %s\n", msg);
                        }
                        putchar('\n');

+                       onelines->strdup_strings = 1;
+                       string_list_clear(onelines, 0);
+                       free(onelines);

                }
 
                }
 

-               onelines->strdup_strings = 1;
-               string_list_clear(onelines, 0);
-               free(onelines);

                log->list.items[i].util = NULL;
        }
 
                log->list.items[i].util = NULL;
        }