repack: convert "names" util bitfield to array

We keep a string_list "names" containing the hashes of packs generated
on our behalf by pack-objects. The util field of each item is treated as
a bitfield that tells us which extensions (.pack, .idx, .rev, etc) are
present for each name.

Let's switch this to allocating a real array. That will give us room in
a future patch to store more data than just a single bit per extension.
And it makes the code a little easier to read, as we avoid casting back
and forth between uintptr_t and a void pointer.

Since the only thing we're storing is an array, we could just allocate
it directly. But instead I've put it into a named struct here. That
further increases readability around the casts, and in particular helps
differentiate us from other string_lists in the same file which use
their util field differently. E.g., the existing_*_packs lists still do
bit-twiddling, but their bits have different meaning than the ones in
"names". This makes it hard to grep around the code to see how the util
fields are used; now you can look for "generated_pack_data".

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

diff --git a/builtin/repack.c b/builtin/repack.c
index a5bacc7797435696cd6e23e73f847fc00d39bb7f..8e71230bf7d6bf785de452911e6b74567f3b7833 100644 (file)
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -247,11 +247,15 @@ static struct {
        {".idx"},
 };
 
-static unsigned populate_pack_exts(char *name)
+struct generated_pack_data {
+       char exts[ARRAY_SIZE(exts)];
+};
+
+static struct generated_pack_data *populate_pack_exts(const char *name)
 {
        struct stat statbuf;
        struct strbuf path = STRBUF_INIT;
-       unsigned ret = 0;
+       struct generated_pack_data *data = xcalloc(1, sizeof(*data));
        int i;
 
        for (i = 0; i < ARRAY_SIZE(exts); i++) {
@@ -261,11 +265,11 @@ static unsigned populate_pack_exts(char *name)
                if (stat(path.buf, &statbuf))
                        continue;
 
-               ret |= (1 << i);
+               data->exts[i] = 1;
        }
 
        strbuf_release(&path);
-       return ret;
+       return data;
 }
 
 static void repack_promisor_objects(const struct pack_objects_args *args,
@@ -320,7 +324,7 @@ static void repack_promisor_objects(const struct pack_objects_args *args,
                                          line.buf);
                write_promisor_file(promisor_name, NULL, 0);
 
-               item->util = (void *)(uintptr_t)populate_pack_exts(item->string);
+               item->util = populate_pack_exts(item->string);
 
                free(promisor_name);
        }
@@ -994,7 +998,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
        string_list_sort(&names);
 
        for_each_string_list_item(item, &names) {
-               item->util = (void *)(uintptr_t)populate_pack_exts(item->string);
+               item->util = populate_pack_exts(item->string);
        }
 
        close_object_store(the_repository->objects);
@@ -1003,6 +1007,8 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
         * Ok we have prepared all new packfiles.
         */
        for_each_string_list_item(item, &names) {
+               struct generated_pack_data *data = item->util;
+
                for (ext = 0; ext < ARRAY_SIZE(exts); ext++) {
                        char *fname, *fname_old;
 
@@ -1011,7 +1017,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
                        fname_old = mkpathdup("%s-%s%s",
                                        packtmp, item->string, exts[ext].name);
 
-                       if (((uintptr_t)item->util) & ((uintptr_t)1 << ext)) {
+                       if (data->exts[ext]) {
                                struct stat statbuffer;
                                if (!stat(fname_old, &statbuffer)) {
                                        statbuffer.st_mode &= ~(S_IWUSR | S_IWGRP | S_IWOTH);
@@ -1115,7 +1121,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
                write_midx_file(get_object_directory(), NULL, NULL, flags);
        }
 
-       string_list_clear(&names, 0);
+       string_list_clear(&names, 1);
        string_list_clear(&existing_nonkept_packs, 0);
        string_list_clear(&existing_kept_packs, 0);
        clear_pack_geometry(geometry);