A future commit will want to implement a very similar routine as in
`stream_blob_to_pack()` with two notable changes:
- Instead of streaming just OBJ_BLOBs, this new function may want to
stream objects of arbitrary type.
- Instead of streaming the object's contents from an open
file-descriptor, this new function may want to "stream" its contents
from memory.
To avoid duplicating a significant chunk of code between the existing
`stream_blob_to_pack()`, extract an abstract `bulk_checkin_source`. This
concept currently is a thin layer of `lseek()` and `read_in_full()`, but
will grow to understand how to perform analogous operations when writing
out an object's contents from memory.
Suggested-by: Junio C Hamano <gitster@xxxxxxxxx>
Signed-off-by: Taylor Blau <me@xxxxxxxxxxxx>
---
bulk-checkin.c | 65 +++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 57 insertions(+), 8 deletions(-)
diff --git a/bulk-checkin.c b/bulk-checkin.c
index 6ce62999e5..174a6c24e4 100644
--- a/bulk-checkin.c
+++ b/bulk-checkin.c
@@ -140,8 +140,49 @@ static int already_written(struct bulk_checkin_packfile *state, struct object_id
return 0;
}
+struct bulk_checkin_source {
+ off_t (*read)(struct bulk_checkin_source *, void *, size_t);
+ off_t (*seek)(struct bulk_checkin_source *, off_t);
+
+ union {
+ struct {
+ int fd;
+ } from_fd;
+ } data;
+
+ size_t size;
+ const char *path;
+};
+
+static off_t bulk_checkin_source_read_from_fd(struct bulk_checkin_source *source,
+ void *buf, size_t nr)
+{
+ return read_in_full(source->data.from_fd.fd, buf, nr);
+}
+
+static off_t bulk_checkin_source_seek_from_fd(struct bulk_checkin_source *source,
+ off_t offset)
+{
+ return lseek(source->data.from_fd.fd, offset, SEEK_SET);
+}
+
+static void init_bulk_checkin_source_from_fd(struct bulk_checkin_source *source,
+ int fd, size_t size,
+ const char *path)
+{
+ memset(source, 0, sizeof(struct bulk_checkin_source));
+
+ source->read = bulk_checkin_source_read_from_fd;
+ source->seek = bulk_checkin_source_seek_from_fd;
+
+ source->data.from_fd.fd = fd;
+
+ source->size = size;
+ source->path = path;
+}
+
/*
- * Read the contents from fd for size bytes, streaming it to the
+ * Read the contents from 'source' for 'size' bytes, streaming it to the
* packfile in state while updating the hash in ctx. Signal a failure
* by returning a negative value when the resulting pack would exceed
* the pack size limit and this is not the first object in the pack,
@@ -157,7 +198,7 @@ static int already_written(struct bulk_checkin_packfile *state, struct object_id
*/
static int stream_blob_to_pack(struct bulk_checkin_packfile *state,
git_hash_ctx *ctx, off_t *already_hashed_to,
- int fd, size_t size, const char *path,
+ struct bulk_checkin_source *source,
unsigned flags)
{
git_zstream s;
@@ -167,22 +208,27 @@ static int stream_blob_to_pack(struct bulk_checkin_packfile *state,
int status = Z_OK;
int write_object = (flags & HASH_WRITE_OBJECT);
off_t offset = 0;
+ size_t size = source->size;
git_deflate_init(&s, pack_compression_level);
- hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), OBJ_BLOB, size);
+ hdrlen = encode_in_pack_object_header(obuf, sizeof(obuf), OBJ_BLOB,
+ size);
s.next_out = obuf + hdrlen;
s.avail_out = sizeof(obuf) - hdrlen;
while (status != Z_STREAM_END) {
if (size && !s.avail_in) {
ssize_t rsize = size < sizeof(ibuf) ? size : sizeof(ibuf);
- ssize_t read_result = read_in_full(fd, ibuf, rsize);
+ ssize_t read_result;
+
+ read_result = source->read(source, ibuf, rsize);
if (read_result < 0)
- die_errno("failed to read from '%s'", path);
+ die_errno("failed to read from '%s'",
+ source->path);
if (read_result != rsize)
die("failed to read %d bytes from '%s'",
- (int)rsize, path);
+ (int)rsize, source->path);
offset += rsize;
if (*already_hashed_to < offset) {
size_t hsize = offset - *already_hashed_to;
@@ -258,6 +304,9 @@ static int deflate_blob_to_pack(struct bulk_checkin_packfile *state,
unsigned header_len;
struct hashfile_checkpoint checkpoint = {0};
struct pack_idx_entry *idx = NULL;
+ struct bulk_checkin_source source;
+
+ init_bulk_checkin_source_from_fd(&source, fd, size, path);
seekback = lseek(fd, 0, SEEK_CUR);
if (seekback == (off_t) -1)
@@ -283,7 +332,7 @@ static int deflate_blob_to_pack(struct bulk_checkin_packfile *state,
crc32_begin(state->f);
}
if (!stream_blob_to_pack(state, &ctx, &already_hashed_to,
- fd, size, path, flags))
+ &source, flags))
break;
/*
* Writing this object to the current pack will make
@@ -295,7 +344,7 @@ static int deflate_blob_to_pack(struct bulk_checkin_packfile *state,
hashfile_truncate(state->f, &checkpoint);
state->offset = checkpoint.offset;
flush_bulk_checkin_packfile(state);
- if (lseek(fd, seekback, SEEK_SET) == (off_t) -1)
+ if (source.seek(&source, seekback) == (off_t)-1)
return error("cannot seek back");
}
the_hash_algo->final_oid_fn(result_oid, &ctx);
--
2.42.0.425.g963d08ddb3.dirty
