[PATCH] sha1_file: use llist_mergesort() for sorting packs

[René Scharfe]

Sort the linked list of packs directly using llist_mergesort() instead
of building an array, calling qsort(3) and fixing up the list pointers.
This is shorter and less complicated.

Signed-off-by: Rene Scharfe <l....@web.de>
---
Peff: Or do you have other plans, e.g. to replace packed_git with
packed_git_mru completely?

 sha1_file.c | 39 +++++++++++++++------------------------
 1 file changed, 15 insertions(+), 24 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index 472ccb2..66dccaa 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -25,6 +25,7 @@
 #include "dir.h"
 #include "mru.h"
 #include "list.h"
+#include "mergesort.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -1380,10 +1381,20 @@ static void prepare_packed_git_one(char *objdir, int 
local)
        strbuf_release(&path);
 }
 
+static void *get_next_packed_git(const void *p)
+{
+       return ((const struct packed_git *)p)->next;
+}
+
+static void set_next_packed_git(void *p, void *next)
+{
+       ((struct packed_git *)p)->next = next;
+}
+
 static int sort_pack(const void *a_, const void *b_)
 {
-       struct packed_git *a = *((struct packed_git **)a_);
-       struct packed_git *b = *((struct packed_git **)b_);
+       const struct packed_git *a = a_;
+       const struct packed_git *b = b_;
        int st;
 
        /*
@@ -1410,28 +1421,8 @@ static int sort_pack(const void *a_, const void *b_)
 
 static void rearrange_packed_git(void)
 {
-       struct packed_git **ary, *p;
-       int i, n;
-
-       for (n = 0, p = packed_git; p; p = p->next)
-               n++;
-       if (n < 2)
-               return;
-
-       /* prepare an array of packed_git for easier sorting */
-       ary = xcalloc(n, sizeof(struct packed_git *));
-       for (n = 0, p = packed_git; p; p = p->next)
-               ary[n++] = p;
-
-       qsort(ary, n, sizeof(struct packed_git *), sort_pack);
-
-       /* link them back again */
-       for (i = 0; i < n - 1; i++)
-               ary[i]->next = ary[i + 1];
-       ary[n - 1]->next = NULL;
-       packed_git = ary[0];
-
-       free(ary);
+       packed_git = llist_mergesort(packed_git, get_next_packed_git,
+                                    set_next_packed_git, sort_pack);
 }
 
 static void prepare_packed_git_mru(void)
-- 
2.10.0