streaming: create structure for packed object streams

As explained in a preceding commit, we want to get rid of the union of
stream-type specific data in `struct odb_read_stream`. Create a new
structure for packed object streams to move towards this design.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/streaming.c b/streaming.c
index ac7b3026f5a6049f67cb96b0b1923d38506ba151..788f04e83ef6c8da14796a56f94ec8f6d0d95ec7 100644 (file)
--- a/streaming.c
+++ b/streaming.c
@@ -39,11 +39,6 @@ struct odb_read_stream {
        enum { z_unused, z_used, z_done, z_error } z_state;
 
        union {
-               struct {
-                       struct packed_git *pack;
-                       off_t pos;
-               } in_pack;
-
                struct filtered_istream filtered;
        } u;
 };
@@ -287,16 +282,23 @@ error:
  *
  *****************************************************************/
 
-static ssize_t read_istream_pack_non_delta(struct odb_read_stream *st, char *buf,
+struct odb_packed_read_stream {
+       struct odb_read_stream base;
+       struct packed_git *pack;
+       off_t pos;
+};
+
+static ssize_t read_istream_pack_non_delta(struct odb_read_stream *_st, char *buf,
                                           size_t sz)
 {
+       struct odb_packed_read_stream *st = (struct odb_packed_read_stream *)_st;
        size_t total_read = 0;
 
-       switch (st->z_state) {
+       switch (st->base.z_state) {
        case z_unused:
-               memset(&st->z, 0, sizeof(st->z));
-               git_inflate_init(&st->z);
-               st->z_state = z_used;
+               memset(&st->base.z, 0, sizeof(st->base.z));
+               git_inflate_init(&st->base.z);
+               st->base.z_state = z_used;
                break;
        case z_done:
                return 0;
@@ -311,21 +313,21 @@ static ssize_t read_istream_pack_non_delta(struct odb_read_stream *st, char *buf
                struct pack_window *window = NULL;
                unsigned char *mapped;
 
-               mapped = use_pack(st->u.in_pack.pack, &window,
-                                 st->u.in_pack.pos, &st->z.avail_in);
+               mapped = use_pack(st->pack, &window,
+                                 st->pos, &st->base.z.avail_in);
 
-               st->z.next_out = (unsigned char *)buf + total_read;
-               st->z.avail_out = sz - total_read;
-               st->z.next_in = mapped;
-               status = git_inflate(&st->z, Z_FINISH);
+               st->base.z.next_out = (unsigned char *)buf + total_read;
+               st->base.z.avail_out = sz - total_read;
+               st->base.z.next_in = mapped;
+               status = git_inflate(&st->base.z, Z_FINISH);
 
-               st->u.in_pack.pos += st->z.next_in - mapped;
-               total_read = st->z.next_out - (unsigned char *)buf;
+               st->pos += st->base.z.next_in - mapped;
+               total_read = st->base.z.next_out - (unsigned char *)buf;
                unuse_pack(&window);
 
                if (status == Z_STREAM_END) {
-                       git_inflate_end(&st->z);
-                       st->z_state = z_done;
+                       git_inflate_end(&st->base.z);
+                       st->base.z_state = z_done;
                        break;
                }
 
@@ -338,17 +340,18 @@ static ssize_t read_istream_pack_non_delta(struct odb_read_stream *st, char *buf
                 * or truncated), then use_pack() catches that and will die().
                 */
                if (status != Z_OK && status != Z_BUF_ERROR) {
-                       git_inflate_end(&st->z);
-                       st->z_state = z_error;
+                       git_inflate_end(&st->base.z);
+                       st->base.z_state = z_error;
                        return -1;
                }
        }
        return total_read;
 }
 
-static int close_istream_pack_non_delta(struct odb_read_stream *st)
+static int close_istream_pack_non_delta(struct odb_read_stream *_st)
 {
-       close_deflated_stream(st);
+       struct odb_packed_read_stream *st = (struct odb_packed_read_stream *)_st;
+       close_deflated_stream(&st->base);
        return 0;
 }
 
@@ -358,19 +361,17 @@ static int open_istream_pack_non_delta(struct odb_read_stream **out,
                                       struct packed_git *pack,
                                       off_t offset)
 {
-       struct odb_read_stream stream = {
-               .close = close_istream_pack_non_delta,
-               .read = read_istream_pack_non_delta,
-       };
+       struct odb_packed_read_stream *stream;
        struct pack_window *window;
        enum object_type in_pack_type;
+       size_t size;
 
        window = NULL;
 
        in_pack_type = unpack_object_header(pack,
                                            &window,
                                            &offset,
-                                           &stream.size);
+                                           &size);
        unuse_pack(&window);
        switch (in_pack_type) {
        default:
@@ -381,13 +382,17 @@ static int open_istream_pack_non_delta(struct odb_read_stream **out,
        case OBJ_TAG:
                break;
        }
-       stream.type = in_pack_type;
-       stream.z_state = z_unused;
-       stream.u.in_pack.pack = pack;
-       stream.u.in_pack.pos = offset;
 
-       CALLOC_ARRAY(*out, 1);
-       **out = stream;
+       CALLOC_ARRAY(stream, 1);
+       stream->base.close = close_istream_pack_non_delta;
+       stream->base.read = read_istream_pack_non_delta;
+       stream->base.type = in_pack_type;
+       stream->base.size = size;
+       stream->base.z_state = z_unused;
+       stream->pack = pack;
+       stream->pos = offset;
+
+       *out = &stream->base;
 
        return 0;
 }