streaming.c: move {open,close,read} from vtable to "struct git_istream"

Move the definition of the structure around the open/close/read
functions introduced in 46bf043807 (streaming: a new API to read from
the object store, 2011-05-11) to instead populate "close" and "read"
members in the "struct git_istream".

This gets us rid of an extra pointer deference, and I think makes more
sense. The "close" and "read" functions are the primary interface to
the stream itself.

Let's also populate a "open" callback in the same struct. That's now
used by open_istream() after istream_source() decides what "open"
function should be used. This isn't needed to get rid of the
"stream_vtbl" variables, but makes sense for consistency.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Ævar Arnfjörð Bjarmason 2021-05-05 14:33:32 +02:00 committed by Junio C Hamano
parent de94c0eace
commit d4e2d15a8b

View File

@ -15,11 +15,6 @@ typedef int (*open_istream_fn)(struct git_istream *,
typedef int (*close_istream_fn)(struct git_istream *);
typedef ssize_t (*read_istream_fn)(struct git_istream *, char *, size_t);
struct stream_vtbl {
close_istream_fn close;
read_istream_fn read;
};
#define FILTER_BUFFER (1024*16)
struct filtered_istream {
@ -33,7 +28,10 @@ struct filtered_istream {
};
struct git_istream {
const struct stream_vtbl *vtbl;
open_istream_fn open;
close_istream_fn close;
read_istream_fn read;
unsigned long size; /* inflated size of full object */
git_zstream z;
enum { z_unused, z_used, z_done, z_error } z_state;
@ -146,18 +144,14 @@ static ssize_t read_istream_filtered(struct git_istream *st, char *buf,
return filled;
}
static struct stream_vtbl filtered_vtbl = {
close_istream_filtered,
read_istream_filtered,
};
static struct git_istream *attach_stream_filter(struct git_istream *st,
struct stream_filter *filter)
{
struct git_istream *ifs = xmalloc(sizeof(*ifs));
struct filtered_istream *fs = &(ifs->u.filtered);
ifs->vtbl = &filtered_vtbl;
ifs->close = close_istream_filtered;
ifs->read = read_istream_filtered;
fs->upstream = st;
fs->filter = filter;
fs->i_end = fs->i_ptr = 0;
@ -225,11 +219,6 @@ static int close_istream_loose(struct git_istream *st)
return 0;
}
static struct stream_vtbl loose_vtbl = {
close_istream_loose,
read_istream_loose,
};
static int open_istream_loose(struct git_istream *st, struct repository *r,
const struct object_id *oid,
enum object_type *type)
@ -251,8 +240,9 @@ static int open_istream_loose(struct git_istream *st, struct repository *r,
st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
st->u.loose.hdr_avail = st->z.total_out;
st->z_state = z_used;
st->close = close_istream_loose;
st->read = read_istream_loose;
st->vtbl = &loose_vtbl;
return 0;
}
@ -328,11 +318,6 @@ static int close_istream_pack_non_delta(struct git_istream *st)
return 0;
}
static struct stream_vtbl pack_non_delta_vtbl = {
close_istream_pack_non_delta,
read_istream_pack_non_delta,
};
static int open_istream_pack_non_delta(struct git_istream *st,
struct repository *r,
const struct object_id *oid,
@ -358,7 +343,9 @@ static int open_istream_pack_non_delta(struct git_istream *st,
break;
}
st->z_state = z_unused;
st->vtbl = &pack_non_delta_vtbl;
st->close = close_istream_pack_non_delta;
st->read = read_istream_pack_non_delta;
return 0;
}
@ -389,17 +376,13 @@ static ssize_t read_istream_incore(struct git_istream *st, char *buf, size_t sz)
return read_size;
}
static struct stream_vtbl incore_vtbl = {
close_istream_incore,
read_istream_incore,
};
static int open_istream_incore(struct git_istream *st, struct repository *r,
const struct object_id *oid, enum object_type *type)
{
st->u.incore.buf = read_object_file_extended(r, oid, type, &st->size, 0);
st->u.incore.read_ptr = 0;
st->vtbl = &incore_vtbl;
st->close = close_istream_incore;
st->read = read_istream_incore;
return st->u.incore.buf ? 0 : -1;
}
@ -408,10 +391,10 @@ static int open_istream_incore(struct git_istream *st, struct repository *r,
* static helpers variables and functions for users of streaming interface
*****************************************************************************/
static open_istream_fn istream_source(struct git_istream *st,
struct repository *r,
const struct object_id *oid,
enum object_type *type)
static int istream_source(struct git_istream *st,
struct repository *r,
const struct object_id *oid,
enum object_type *type)
{
unsigned long size;
int status;
@ -421,20 +404,23 @@ static open_istream_fn istream_source(struct git_istream *st,
oi.sizep = &size;
status = oid_object_info_extended(r, oid, &oi, 0);
if (status < 0)
return NULL;
return status;
switch (oi.whence) {
case OI_LOOSE:
return open_istream_loose;
st->open = open_istream_loose;
return 0;
case OI_PACKED:
if (!oi.u.packed.is_delta && big_file_threshold < size) {
st->u.in_pack.pack = oi.u.packed.pack;
st->u.in_pack.pos = oi.u.packed.offset;
return open_istream_pack_non_delta;
st->open = open_istream_pack_non_delta;
return 0;
}
/* fallthru */
default:
return open_istream_incore;
st->open = open_istream_incore;
return 0;
}
}
@ -444,14 +430,14 @@ static open_istream_fn istream_source(struct git_istream *st,
int close_istream(struct git_istream *st)
{
int r = st->vtbl->close(st);
int r = st->close(st);
free(st);
return r;
}
ssize_t read_istream(struct git_istream *st, void *buf, size_t sz)
{
return st->vtbl->read(st, buf, sz);
return st->read(st, buf, sz);
}
struct git_istream *open_istream(struct repository *r,
@ -462,14 +448,14 @@ struct git_istream *open_istream(struct repository *r,
{
struct git_istream *st = xmalloc(sizeof(*st));
const struct object_id *real = lookup_replace_object(r, oid);
open_istream_fn open_fn = istream_source(st, r, real, type);
int ret = istream_source(st, r, real, type);
if (!open_fn) {
if (ret) {
free(st);
return NULL;
}
if (open_fn(st, r, real, type)) {
if (st->open(st, r, real, type)) {
if (open_istream_incore(st, r, real, type)) {
free(st);
return NULL;