streaming: create structure for in-core 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 in-core 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 a2c2d887387c575d3375aeab0a4ad2e24e365fc9..35307d72295988f15c604bd1b8694c156defac3c 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 {
-                       char *buf; /* from odb_read_object_info_extended() */
-                       unsigned long read_ptr;
-               } incore;
-
                struct {
                        void *mapped;
                        unsigned long mapsize;
@@ -401,22 +396,30 @@ static int open_istream_pack_non_delta(struct odb_read_stream **out,
  *
  *****************************************************************/
 
-static int close_istream_incore(struct odb_read_stream *st)
+struct odb_incore_read_stream {
+       struct odb_read_stream base;
+       char *buf; /* from odb_read_object_info_extended() */
+       unsigned long read_ptr;
+};
+
+static int close_istream_incore(struct odb_read_stream *_st)
 {
-       free(st->u.incore.buf);
+       struct odb_incore_read_stream *st = (struct odb_incore_read_stream *)_st;
+       free(st->buf);
        return 0;
 }
 
-static ssize_t read_istream_incore(struct odb_read_stream *st, char *buf, size_t sz)
+static ssize_t read_istream_incore(struct odb_read_stream *_st, char *buf, size_t sz)
 {
+       struct odb_incore_read_stream *st = (struct odb_incore_read_stream *)_st;
        size_t read_size = sz;
-       size_t remainder = st->size - st->u.incore.read_ptr;
+       size_t remainder = st->base.size - st->read_ptr;
 
        if (remainder <= read_size)
                read_size = remainder;
        if (read_size) {
-               memcpy(buf, st->u.incore.buf + st->u.incore.read_ptr, read_size);
-               st->u.incore.read_ptr += read_size;
+               memcpy(buf, st->buf + st->read_ptr, read_size);
+               st->read_ptr += read_size;
        }
        return read_size;
 }
@@ -426,22 +429,25 @@ static int open_istream_incore(struct odb_read_stream **out,
                               const struct object_id *oid)
 {
        struct object_info oi = OBJECT_INFO_INIT;
-       struct odb_read_stream stream = {
-               .close = close_istream_incore,
-               .read = read_istream_incore,
+       struct odb_incore_read_stream stream = {
+               .base.close = close_istream_incore,
+               .base.read = read_istream_incore,
        };
+       struct odb_incore_read_stream *st;
        int ret;
 
-       oi.typep = &stream.type;
-       oi.sizep = &stream.size;
-       oi.contentp = (void **)&stream.u.incore.buf;
+       oi.typep = &stream.base.type;
+       oi.sizep = &stream.base.size;
+       oi.contentp = (void **)&stream.buf;
        ret = odb_read_object_info_extended(r->objects, oid, &oi,
                                            OBJECT_INFO_DIE_IF_CORRUPT);
        if (ret)
                return ret;
 
-       CALLOC_ARRAY(*out, 1);
-       **out = stream;
+       CALLOC_ARRAY(st, 1);
+       *st = stream;
+       *out = &st->base;
+
        return 0;
 }