pack-objects: parameterize pack-reuse routines over a single pack

The routines pack-objects uses to perform verbatim pack-reuse are:

  - write_reused_pack_one()
  - write_reused_pack_verbatim()
  - write_reused_pack()

, all of which assume that there is exactly one packfile being reused:
the global constant `reuse_packfile`.

Prepare for reusing objects from multiple packs by making reuse packfile
a parameter of each of the above functions in preparation for calling
these functions in a loop with multiple packfiles.

Note that we still have the global "reuse_packfile", but pass it through
each of the above function's parameter lists, eliminating all but one
direct access (the top-level caller in `write_pack_file()`). Even after
this series, we will still have a global, but it will hold the array of
reusable packfiles, and we'll pass them one at a time to these functions
in a loop.

Note also that we will eventually need to pass a `bitmapped_pack`
instead of a `packed_git` in order to hold onto additional information
required for reuse (such as the bit position of the first object
belonging to that pack). But that change will be made in a future commit
so as to minimize the noise below as much as possible.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 87e16636a8035941bdcaf3b03c76343abe6ba4e3..102fe9a4f86f7939e48f8e66bfdb917c3be1a843 100644 (file)
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -1013,7 +1013,8 @@ static off_t find_reused_offset(off_t where)
        return reused_chunks[lo-1].difference;
 }
 
-static void write_reused_pack_one(size_t pos, struct hashfile *out,
+static void write_reused_pack_one(struct packed_git *reuse_packfile,
+                                 size_t pos, struct hashfile *out,
                                  struct pack_window **w_curs)
 {
        off_t offset, next, cur;
@@ -1091,7 +1092,8 @@ static void write_reused_pack_one(size_t pos, struct hashfile *out,
        copy_pack_data(out, reuse_packfile, w_curs, offset, next - offset);
 }
 
-static size_t write_reused_pack_verbatim(struct hashfile *out,
+static size_t write_reused_pack_verbatim(struct packed_git *reuse_packfile,
+                                        struct hashfile *out,
                                         struct pack_window **w_curs)
 {
        size_t pos = 0;
@@ -1118,14 +1120,15 @@ static size_t write_reused_pack_verbatim(struct hashfile *out,
        return pos;
 }
 
-static void write_reused_pack(struct hashfile *f)
+static void write_reused_pack(struct packed_git *reuse_packfile,
+                             struct hashfile *f)
 {
        size_t i = 0;
        uint32_t offset;
        struct pack_window *w_curs = NULL;
 
        if (allow_ofs_delta)
-               i = write_reused_pack_verbatim(f, &w_curs);
+               i = write_reused_pack_verbatim(reuse_packfile, f, &w_curs);
 
        for (; i < reuse_packfile_bitmap->word_alloc; ++i) {
                eword_t word = reuse_packfile_bitmap->words[i];
@@ -1141,7 +1144,8 @@ static void write_reused_pack(struct hashfile *f)
                         * bitmaps. See comment in try_partial_reuse()
                         * for why.
                         */
-                       write_reused_pack_one(pos + offset, f, &w_curs);
+                       write_reused_pack_one(reuse_packfile, pos + offset, f,
+                                             &w_curs);
                        display_progress(progress_state, ++written);
                }
        }
@@ -1199,7 +1203,7 @@ static void write_pack_file(void)
 
                if (reuse_packfile) {
                        assert(pack_to_stdout);
-                       write_reused_pack(f);
+                       write_reused_pack(reuse_packfile, f);
                        offset = hashfile_total(f);
                }