From 43eadce3407aa63829633b5dc903db79f4cdf29e Mon Sep 17 00:00:00 2001 From: Justin Tobler Date: Thu, 2 Apr 2026 16:32:17 -0500 Subject: [PATCH] object-file: remove flags from transaction packfile writes The `index_blob_packfile_transaction()` function handles streaming a blob from an fd to compute its object ID and conditionally writes the object directly to a packfile if the INDEX_WRITE_OBJECT flag is set. A subsequent commit will make these packfile object writes part of the transaction interface. Consequently, having the object write be conditional on this flag is a bit awkward. In preparation for this change, introduce a dedicated `hash_blob_stream()` helper that only computes the OID from a `struct odb_write_stream`. This is invoked by `index_fd()` instead when the INDEX_WRITE_OBJECT is not set. The object write performed via `index_blob_packfile_transaction()` is made unconditional accordingly. Signed-off-by: Justin Tobler Signed-off-by: Junio C Hamano --- object-file.c | 128 +++++++++++++++++++++++++++++------------------- odb/streaming.c | 46 +++++++++++++++++ odb/streaming.h | 12 +++++ 3 files changed, 136 insertions(+), 50 deletions(-) diff --git a/object-file.c b/object-file.c index 0ae36314aa..382d14c8c0 100644 --- a/object-file.c +++ b/object-file.c @@ -1396,11 +1396,10 @@ static int already_written(struct odb_transaction_files *transaction, } /* Lazily create backing packfile for the state */ -static void prepare_packfile_transaction(struct odb_transaction_files *transaction, - unsigned flags) +static void prepare_packfile_transaction(struct odb_transaction_files *transaction) { struct transaction_packfile *state = &transaction->packfile; - if (!(flags & INDEX_WRITE_OBJECT) || state->f) + if (state->f) return; state->f = create_tmp_packfile(transaction->base.source->odb->repo, @@ -1413,6 +1412,39 @@ static void prepare_packfile_transaction(struct odb_transaction_files *transacti die_errno("unable to write pack header"); } +static int hash_blob_stream(struct odb_write_stream *stream, + const struct git_hash_algo *hash_algo, + struct object_id *result_oid, size_t size) +{ + unsigned char buf[16384]; + struct git_hash_ctx ctx; + unsigned header_len; + size_t bytes_hashed = 0; + + header_len = format_object_header((char *)buf, sizeof(buf), + OBJ_BLOB, size); + hash_algo->init_fn(&ctx); + git_hash_update(&ctx, buf, header_len); + + while (!stream->is_finished) { + ssize_t read_result = odb_write_stream_read(stream, buf, + sizeof(buf)); + + if (read_result < 0) + return -1; + + git_hash_update(&ctx, buf, read_result); + bytes_hashed += read_result; + } + + if (bytes_hashed != size) + return -1; + + git_hash_final_oid(result_oid, &ctx); + + return 0; +} + /* * Read the contents from fd for size bytes, streaming it to the * packfile in state while updating the hash in ctx. Signal a failure @@ -1430,15 +1462,13 @@ static void prepare_packfile_transaction(struct odb_transaction_files *transacti */ static int stream_blob_to_pack(struct transaction_packfile *state, struct git_hash_ctx *ctx, off_t *already_hashed_to, - int fd, size_t size, const char *path, - unsigned flags) + int fd, size_t size, const char *path) { git_zstream s; unsigned char ibuf[16384]; unsigned char obuf[16384]; unsigned hdrlen; int status = Z_OK; - int write_object = (flags & INDEX_WRITE_OBJECT); off_t offset = 0; git_deflate_init(&s, pack_compression_level); @@ -1473,20 +1503,18 @@ static int stream_blob_to_pack(struct transaction_packfile *state, status = git_deflate(&s, size ? 0 : Z_FINISH); if (!s.avail_out || status == Z_STREAM_END) { - if (write_object) { - size_t written = s.next_out - obuf; + size_t written = s.next_out - obuf; - /* would we bust the size limit? */ - if (state->nr_written && - pack_size_limit_cfg && - pack_size_limit_cfg < state->offset + written) { - git_deflate_abort(&s); - return -1; - } - - hashwrite(state->f, obuf, written); - state->offset += written; + /* would we bust the size limit? */ + if (state->nr_written && + pack_size_limit_cfg && + pack_size_limit_cfg < state->offset + written) { + git_deflate_abort(&s); + return -1; } + + hashwrite(state->f, obuf, written); + state->offset += written; s.next_out = obuf; s.avail_out = sizeof(obuf); } @@ -1574,8 +1602,7 @@ clear_exit: */ static int index_blob_packfile_transaction(struct odb_transaction_files *transaction, struct object_id *result_oid, int fd, - size_t size, const char *path, - unsigned flags) + size_t size, const char *path) { struct transaction_packfile *state = &transaction->packfile; off_t seekback, already_hashed_to; @@ -1583,7 +1610,7 @@ static int index_blob_packfile_transaction(struct odb_transaction_files *transac unsigned char obuf[16384]; unsigned header_len; struct hashfile_checkpoint checkpoint; - struct pack_idx_entry *idx = NULL; + struct pack_idx_entry *idx; seekback = lseek(fd, 0, SEEK_CUR); if (seekback == (off_t)-1) @@ -1594,33 +1621,26 @@ static int index_blob_packfile_transaction(struct odb_transaction_files *transac transaction->base.source->odb->repo->hash_algo->init_fn(&ctx); git_hash_update(&ctx, obuf, header_len); - /* Note: idx is non-NULL when we are writing */ - if ((flags & INDEX_WRITE_OBJECT) != 0) { - CALLOC_ARRAY(idx, 1); - - prepare_packfile_transaction(transaction, flags); - hashfile_checkpoint_init(state->f, &checkpoint); - } + CALLOC_ARRAY(idx, 1); + prepare_packfile_transaction(transaction); + hashfile_checkpoint_init(state->f, &checkpoint); already_hashed_to = 0; while (1) { - prepare_packfile_transaction(transaction, flags); - if (idx) { - hashfile_checkpoint(state->f, &checkpoint); - idx->offset = state->offset; - crc32_begin(state->f); - } + prepare_packfile_transaction(transaction); + hashfile_checkpoint(state->f, &checkpoint); + idx->offset = state->offset; + crc32_begin(state->f); + if (!stream_blob_to_pack(state, &ctx, &already_hashed_to, - fd, size, path, flags)) + fd, size, path)) break; /* * Writing this object to the current pack will make * it too big; we need to truncate it, start a new * pack, and write into it. */ - if (!idx) - BUG("should not happen"); hashfile_truncate(state->f, &checkpoint); state->offset = checkpoint.offset; flush_packfile_transaction(transaction); @@ -1628,8 +1648,6 @@ static int index_blob_packfile_transaction(struct odb_transaction_files *transac return error("cannot seek back"); } git_hash_final_oid(result_oid, &ctx); - if (!idx) - return 0; idx->crc32 = crc32_end(state->f); if (already_written(transaction, result_oid)) { @@ -1667,18 +1685,28 @@ int index_fd(struct index_state *istate, struct object_id *oid, ret = index_core(istate, oid, fd, xsize_t(st->st_size), type, path, flags); } else { - struct object_database *odb = the_repository->objects; - struct odb_transaction_files *files_transaction; - struct odb_transaction *transaction; + struct odb_write_stream stream; + odb_write_stream_from_fd(&stream, fd, xsize_t(st->st_size)); - transaction = odb_transaction_begin(odb); - files_transaction = container_of(odb->transaction, - struct odb_transaction_files, - base); - ret = index_blob_packfile_transaction(files_transaction, oid, fd, - xsize_t(st->st_size), - path, flags); - odb_transaction_commit(transaction); + if (flags & INDEX_WRITE_OBJECT) { + struct object_database *odb = the_repository->objects; + struct odb_transaction_files *files_transaction; + struct odb_transaction *transaction; + + transaction = odb_transaction_begin(odb); + files_transaction = container_of(odb->transaction, + struct odb_transaction_files, + base); + ret = index_blob_packfile_transaction(files_transaction, oid, fd, + xsize_t(st->st_size), path); + odb_transaction_commit(transaction); + } else { + ret = hash_blob_stream(&stream, + the_repository->hash_algo, oid, + xsize_t(st->st_size)); + } + + odb_write_stream_release(&stream); } close(fd); diff --git a/odb/streaming.c b/odb/streaming.c index a68dd2cbe3..20531e864c 100644 --- a/odb/streaming.c +++ b/odb/streaming.c @@ -237,6 +237,11 @@ ssize_t odb_write_stream_read(struct odb_write_stream *st, void *buf, size_t sz) return st->read(st, buf, sz); } +void odb_write_stream_release(struct odb_write_stream *st) +{ + free(st->data); +} + int odb_stream_blob_to_fd(struct object_database *odb, int fd, const struct object_id *oid, @@ -292,3 +297,44 @@ int odb_stream_blob_to_fd(struct object_database *odb, odb_read_stream_close(st); return result; } + +struct read_object_fd_data { + int fd; + size_t remaining; +}; + +static ssize_t read_object_fd(struct odb_write_stream *stream, + unsigned char *buf, size_t len) +{ + struct read_object_fd_data *data = stream->data; + ssize_t read_result; + size_t count; + + if (stream->is_finished) + return 0; + + count = data->remaining < len ? data->remaining : len; + read_result = read_in_full(data->fd, buf, count); + if (read_result < 0 || (size_t)read_result != count) + return -1; + + data->remaining -= count; + if (!data->remaining) + stream->is_finished = 1; + + return read_result; +} + +void odb_write_stream_from_fd(struct odb_write_stream *stream, int fd, + size_t size) +{ + struct read_object_fd_data *data; + + CALLOC_ARRAY(data, 1); + data->fd = fd; + data->remaining = size; + + stream->data = data; + stream->read = read_object_fd; + stream->is_finished = 0; +} diff --git a/odb/streaming.h b/odb/streaming.h index 65ced911fe..2a8cac19a4 100644 --- a/odb/streaming.h +++ b/odb/streaming.h @@ -5,6 +5,7 @@ #define STREAMING_H 1 #include "object.h" +#include "odb.h" struct object_database; struct odb_read_stream; @@ -65,6 +66,11 @@ struct odb_write_stream { ssize_t odb_write_stream_read(struct odb_write_stream *stream, void *buf, size_t len); +/* + * Releases memory allocated for underlying stream data. + */ +void odb_write_stream_release(struct odb_write_stream *stream); + /* * Look up the object by its ID and write the full contents to the file * descriptor. The object must be a blob, or the function will fail. When @@ -82,4 +88,10 @@ int odb_stream_blob_to_fd(struct object_database *odb, struct stream_filter *filter, int can_seek); +/* + * Sets up an ODB write stream that reads from an fd. + */ +void odb_write_stream_from_fd(struct odb_write_stream *stream, int fd, + size_t size); + #endif /* STREAMING_H */