odb: introduce `odb_write_object()`

We do not have a backend-agnostic way to write objects into an object
database. While there is `write_object_file()`, this function is rather
specific to the loose object format.

Introduce `odb_write_object()` to plug this gap. For now, this function
is a simple wrapper around `write_object_file()` and doesn't even use
the passed-in object database yet. This will change in subsequent
commits, where `write_object_file()` is converted so that it works on
top of an `odb_source`. `odb_write_object()` will then become
responsible for deciding which source an object shall be written to.

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

apply.c

@@ -3621,7 +3621,7 @@ static int try_threeway(struct apply_state *state,
 
 	/* Preimage the patch was prepared for */
 	if (patch->is_new)
-		write_object_file("", 0, OBJ_BLOB, &pre_oid);
+		odb_write_object(the_repository->objects, "", 0, OBJ_BLOB, &pre_oid);
 	else if (repo_get_oid(the_repository, patch->old_oid_prefix, &pre_oid) ||
 		 read_blob_object(&buf, &pre_oid, patch->old_mode))
 		return error(_("repository lacks the necessary blob to perform 3-way merge."));
@@ -3637,7 +3637,8 @@ static int try_threeway(struct apply_state *state,
 		return -1;
 	}
 	/* post_oid is theirs */
-	write_object_file(tmp_image.buf.buf, tmp_image.buf.len, OBJ_BLOB, &post_oid);
+	odb_write_object(the_repository->objects, tmp_image.buf.buf,
+			 tmp_image.buf.len, OBJ_BLOB, &post_oid);
 	image_clear(&tmp_image);
 
 	/* our_oid is ours */
@@ -3650,7 +3651,8 @@ static int try_threeway(struct apply_state *state,
 			return error(_("cannot read the current contents of '%s'"),
 				     patch->old_name);
 	}
-	write_object_file(tmp_image.buf.buf, tmp_image.buf.len, OBJ_BLOB, &our_oid);
+	odb_write_object(the_repository->objects, tmp_image.buf.buf,
+			 tmp_image.buf.len, OBJ_BLOB, &our_oid);
 	image_clear(&tmp_image);
 
 	/* in-core three-way merge between post and our using pre as base */
@@ -4360,7 +4362,8 @@ static int add_index_file(struct apply_state *state,
 			}
 			fill_stat_cache_info(state->repo->index, ce, &st);
 		}
-		if (write_object_file(buf, size, OBJ_BLOB, &ce->oid) < 0) {
+		if (odb_write_object(the_repository->objects, buf, size,
+				     OBJ_BLOB, &ce->oid) < 0) {
 			discard_cache_entry(ce);
 			return error(_("unable to create backing store "
 				       "for newly created file %s"), path);

builtin/checkout.c

@@ -320,7 +320,7 @@ static int checkout_merged(int pos, const struct checkout *state,
 	 * (it also writes the merge result to the object database even
 	 * when it may contain conflicts).
 	 */
-	if (write_object_file(result_buf.ptr, result_buf.size, OBJ_BLOB, &oid))
+	if (odb_write_object(the_repository->objects, result_buf.ptr, result_buf.size, OBJ_BLOB, &oid))
 		die(_("Unable to add merge result for '%s'"), path);
 	free(result_buf.ptr);
 	ce = make_transient_cache_entry(mode, &oid, path, 2, ce_mem_pool);

builtin/merge-file.c

@@ -155,7 +155,8 @@ int cmd_merge_file(int argc,
 		if (object_id && !to_stdout) {
 			struct object_id oid;
 			if (result.size) {
-				if (write_object_file(result.ptr, result.size, OBJ_BLOB, &oid) < 0)
+				if (odb_write_object(the_repository->objects, result.ptr,
+						     result.size, OBJ_BLOB, &oid) < 0)
 					ret = error(_("Could not write object file"));
 			} else {
 				oidcpy(&oid, the_hash_algo->empty_blob);

builtin/mktag.c

@@ -106,7 +106,7 @@ int cmd_mktag(int argc,
 	if (verify_object_in_tag(&tagged_oid, &tagged_type) < 0)
 		die(_("tag on stdin did not refer to a valid object"));
 
-	if (write_object_file(buf.buf, buf.len, OBJ_TAG, &result) < 0)
+	if (odb_write_object(the_repository->objects, buf.buf, buf.len, OBJ_TAG, &result) < 0)
 		die(_("unable to write tag file"));
 
 	strbuf_release(&buf);

builtin/mktree.c

@@ -63,7 +63,7 @@ static void write_tree(struct object_id *oid)
 		strbuf_add(&buf, ent->oid.hash, the_hash_algo->rawsz);
 	}
 
-	write_object_file(buf.buf, buf.len, OBJ_TREE, oid);
+	odb_write_object(the_repository->objects, buf.buf, buf.len, OBJ_TREE, oid);
 	strbuf_release(&buf);
 }
 

builtin/notes.c

@@ -229,7 +229,8 @@ static void prepare_note_data(const struct object_id *object, struct note_data *
 
 static void write_note_data(struct note_data *d, struct object_id *oid)
 {
-	if (write_object_file(d->buf.buf, d->buf.len, OBJ_BLOB, oid)) {
+	if (odb_write_object(the_repository->objects, d->buf.buf,
+			     d->buf.len, OBJ_BLOB, oid)) {
 		int status = die_message(_("unable to write note object"));
 
 		if (d->edit_path)

builtin/receive-pack.c

@@ -760,8 +760,8 @@ static void prepare_push_cert_sha1(struct child_process *proc)
 		int bogs /* beginning_of_gpg_sig */;
 
 		already_done = 1;
-		if (write_object_file(push_cert.buf, push_cert.len, OBJ_BLOB,
-				      &push_cert_oid))
+		if (odb_write_object(the_repository->objects, push_cert.buf,
+				     push_cert.len, OBJ_BLOB, &push_cert_oid))
 			oidclr(&push_cert_oid, the_repository->hash_algo);
 
 		memset(&sigcheck, '\0', sizeof(sigcheck));

builtin/replace.c

@@ -488,7 +488,8 @@ static int create_graft(int argc, const char **argv, int force, int gentle)
 		return -1;
 	}
 
-	if (write_object_file(buf.buf, buf.len, OBJ_COMMIT, &new_oid)) {
+	if (odb_write_object(the_repository->objects, buf.buf,
+			     buf.len, OBJ_COMMIT, &new_oid)) {
 		strbuf_release(&buf);
 		return error(_("could not write replacement commit for: '%s'"),
 			     old_ref);

builtin/tag.c

@@ -271,8 +271,8 @@ static int build_tag_object(struct strbuf *buf, int sign, struct object_id *resu
 	struct object_id *compat_oid = NULL, compat_oid_buf;
 	if (sign && do_sign(buf, &compat_oid, &compat_oid_buf) < 0)
 		return error(_("unable to sign the tag"));
-	if (write_object_file_flags(buf->buf, buf->len, OBJ_TAG, result,
-				    compat_oid, 0) < 0)
+	if (odb_write_object_ext(the_repository->objects, buf->buf,
+				 buf->len, OBJ_TAG, result, compat_oid, 0) < 0)
 		return error(_("unable to write tag file"));
 	return 0;
 }

builtin/unpack-objects.c

@@ -204,7 +204,7 @@ static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
 {
 	struct object_id oid;
 
-	if (write_object_file(obj_buf->buffer, obj_buf->size,
+	if (odb_write_object(the_repository->objects, obj_buf->buffer, obj_buf->size,
 			     obj->type, &oid) < 0)
 		die("failed to write object %s", oid_to_hex(&obj->oid));
 	obj->flags |= FLAG_WRITTEN;
@@ -272,7 +272,7 @@ static void write_object(unsigned nr, enum object_type type,
 			 void *buf, unsigned long size)
 {
 	if (!strict) {
-		if (write_object_file(buf, size, type,
+		if (odb_write_object(the_repository->objects, buf, size, type,
 				     &obj_list[nr].oid) < 0)
 			die("failed to write object");
 		added_object(nr, type, buf, size);
@@ -280,7 +280,7 @@ static void write_object(unsigned nr, enum object_type type,
 		obj_list[nr].obj = NULL;
 	} else if (type == OBJ_BLOB) {
 		struct blob *blob;
-		if (write_object_file(buf, size, type,
+		if (odb_write_object(the_repository->objects, buf, size, type,
 				     &obj_list[nr].oid) < 0)
 			die("failed to write object");
 		added_object(nr, type, buf, size);

cache-tree.c

@@ -456,9 +456,8 @@ static int update_one(struct cache_tree *it,
 	} else if (dryrun) {
 		hash_object_file(the_hash_algo, buffer.buf, buffer.len,
 				 OBJ_TREE, &it->oid);
-	} else if (write_object_file_flags(buffer.buf, buffer.len, OBJ_TREE,
-					   &it->oid, NULL, flags & WRITE_TREE_SILENT
-					   ? WRITE_OBJECT_FILE_SILENT : 0)) {
+	} else if (odb_write_object_ext(the_repository->objects, buffer.buf, buffer.len, OBJ_TREE,
+					&it->oid, NULL, flags & WRITE_TREE_SILENT ? WRITE_OBJECT_SILENT : 0)) {
 		strbuf_release(&buffer);
 		return -1;
 	}

commit.c

@@ -1797,8 +1797,8 @@ int commit_tree_extended(const char *msg, size_t msg_len,
 		compat_oid = &compat_oid_buf;
 	}
 
-	result = write_object_file_flags(buffer.buf, buffer.len, OBJ_COMMIT,
-					 ret, compat_oid, 0);
+	result = odb_write_object_ext(the_repository->objects, buffer.buf, buffer.len,
+				      OBJ_COMMIT, ret, compat_oid, 0);
 out:
 	free(parent_buf);
 	strbuf_release(&buffer);

match-trees.c

@@ -246,7 +246,7 @@ static int splice_tree(struct repository *r,
 		rewrite_with = oid2;
 	}
 	hashcpy(rewrite_here, rewrite_with->hash, r->hash_algo);
-	status = write_object_file(buf, sz, OBJ_TREE, result);
+	status = odb_write_object(r->objects, buf, sz, OBJ_TREE, result);
 	free(buf);
 	return status;
 }

merge-ort.c

@@ -2216,7 +2216,7 @@ static int handle_content_merge(struct merge_options *opt,
 		}
 
 		if (!ret && record_object &&
-		    write_object_file(result_buf.ptr, result_buf.size,
+		    odb_write_object(the_repository->objects, result_buf.ptr, result_buf.size,
 				     OBJ_BLOB, &result->oid)) {
 			path_msg(opt, ERROR_OBJECT_WRITE_FAILED, 0,
 				 pathnames[0], pathnames[1], pathnames[2], NULL,
@@ -3772,7 +3772,8 @@ static int write_tree(struct object_id *result_oid,
 	}
 
 	/* Write this object file out, and record in result_oid */
-	if (write_object_file(buf.buf, buf.len, OBJ_TREE, result_oid))
+	if (odb_write_object(the_repository->objects, buf.buf,
+			     buf.len, OBJ_TREE, result_oid))
 		ret = -1;
 	strbuf_release(&buf);
 	return ret;

notes-cache.c

@@ -98,7 +98,8 @@ int notes_cache_put(struct notes_cache *c, struct object_id *key_oid,
 {
 	struct object_id value_oid;
 
-	if (write_object_file(data, size, OBJ_BLOB, &value_oid) < 0)
+	if (odb_write_object(the_repository->objects, data,
+			     size, OBJ_BLOB, &value_oid) < 0)
 		return -1;
 	return add_note(&c->tree, key_oid, &value_oid, NULL);
 }

notes.c

@@ -682,7 +682,8 @@ static int tree_write_stack_finish_subtree(struct tree_write_stack *tws)
 		ret = tree_write_stack_finish_subtree(n);
 		if (ret)
 			return ret;
-		ret = write_object_file(n->buf.buf, n->buf.len, OBJ_TREE, &s);
+		ret = odb_write_object(the_repository->objects, n->buf.buf,
+				       n->buf.len, OBJ_TREE, &s);
 		if (ret)
 			return ret;
 		strbuf_release(&n->buf);
@@ -847,7 +848,8 @@ int combine_notes_concatenate(struct object_id *cur_oid,
 	free(new_msg);
 
 	/* create a new blob object from buf */
-	ret = write_object_file(buf, buf_len, OBJ_BLOB, cur_oid);
+	ret = odb_write_object(the_repository->objects, buf,
+			       buf_len, OBJ_BLOB, cur_oid);
 	free(buf);
 	return ret;
 }
@@ -927,7 +929,8 @@ int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
 				 string_list_join_lines_helper, &buf))
 		goto out;
 
-	ret = write_object_file(buf.buf, buf.len, OBJ_BLOB, cur_oid);
+	ret = odb_write_object(the_repository->objects, buf.buf,
+			       buf.len, OBJ_BLOB, cur_oid);
 
 out:
 	strbuf_release(&buf);
@@ -1215,7 +1218,8 @@ int write_notes_tree(struct notes_tree *t, struct object_id *result)
 	ret = for_each_note(t, flags, write_each_note, &cb_data) ||
 	      write_each_non_note_until(NULL, &cb_data) ||
 	      tree_write_stack_finish_subtree(&root) ||
-	      write_object_file(root.buf.buf, root.buf.len, OBJ_TREE, result);
+	      odb_write_object(the_repository->objects, root.buf.buf,
+			       root.buf.len, OBJ_TREE, result);
 	strbuf_release(&root.buf);
 	return ret;
 }

object-file.c

@@ -755,7 +755,7 @@ static int start_loose_object_common(struct strbuf *tmp_file,
 
 	fd = create_tmpfile(tmp_file, filename);
 	if (fd < 0) {
-		if (flags & WRITE_OBJECT_FILE_SILENT)
+		if (flags & WRITE_OBJECT_SILENT)
 			return -1;
 		else if (errno == EACCES)
 			return error(_("insufficient permission for adding "
@@ -887,7 +887,7 @@ static int write_loose_object(const struct object_id *oid, char *hdr,
 		utb.actime = mtime;
 		utb.modtime = mtime;
 		if (utime(tmp_file.buf, &utb) < 0 &&
-		    !(flags & WRITE_OBJECT_FILE_SILENT))
+		    !(flags & WRITE_OBJECT_SILENT))
 			warning_errno(_("failed utime() on %s"), tmp_file.buf);
 	}
 
@@ -1032,7 +1032,7 @@ cleanup:
 	return err;
 }
 
-int write_object_file_flags(const void *buf, unsigned long len,
+int write_object_file(const void *buf, unsigned long len,
 		      enum object_type type, struct object_id *oid,
 		      struct object_id *compat_oid_in, unsigned flags)
 {
@@ -1159,7 +1159,7 @@ static int index_mem(struct index_state *istate,
 	}
 
 	if (write_object)
-		ret = write_object_file(buf, size, type, oid);
+		ret = odb_write_object(istate->repo->objects, buf, size, type, oid);
 	else
 		hash_object_file(istate->repo->hash_algo, buf, size, type, oid);
 
@@ -1184,7 +1184,7 @@ static int index_stream_convert_blob(struct index_state *istate,
 				 get_conv_flags(flags));
 
 	if (write_object)
-		ret = write_object_file(sbuf.buf, sbuf.len, OBJ_BLOB,
+		ret = odb_write_object(istate->repo->objects, sbuf.buf, sbuf.len, OBJ_BLOB,
 				       oid);
 	else
 		hash_object_file(istate->repo->hash_algo, sbuf.buf, sbuf.len, OBJ_BLOB,
@@ -1287,7 +1287,7 @@ int index_path(struct index_state *istate, struct object_id *oid,
 		if (!(flags & INDEX_WRITE_OBJECT))
 			hash_object_file(istate->repo->hash_algo, sb.buf, sb.len,
 					 OBJ_BLOB, oid);
-		else if (write_object_file(sb.buf, sb.len, OBJ_BLOB, oid))
+		else if (odb_write_object(the_repository->objects, sb.buf, sb.len, OBJ_BLOB, oid))
 			rc = error(_("%s: failed to insert into database"), path);
 		strbuf_release(&sb);
 		break;

object-file.h

@@ -157,29 +157,9 @@ enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
 struct object_info;
 int parse_loose_header(const char *hdr, struct object_info *oi);
 
-enum {
-	/*
-	 * By default, `write_object_file()` does not actually write
-	 * anything into the object store, but only computes the object ID.
-	 * This flag changes that so that the object will be written as a loose
-	 * object and persisted.
-	 */
-	WRITE_OBJECT_FILE_PERSIST = (1 << 0),
-
-	/*
-	 * Do not print an error in case something gose wrong.
-	 */
-	WRITE_OBJECT_FILE_SILENT = (1 << 1),
-};
-
-int write_object_file_flags(const void *buf, unsigned long len,
+int write_object_file(const void *buf, unsigned long len,
 		      enum object_type type, struct object_id *oid,
 		      struct object_id *compat_oid_in, unsigned flags);
-static inline int write_object_file(const void *buf, unsigned long len,
-				    enum object_type type, struct object_id *oid)
-{
-	return write_object_file_flags(buf, len, type, oid, NULL, 0);
-}
 
 struct input_stream {
 	const void *(*read)(struct input_stream *, unsigned long *len);

odb.c

@@ -980,6 +980,16 @@ void odb_assert_oid_type(struct object_database *odb,
 		    type_name(expect));
 }
 
+int odb_write_object_ext(struct object_database *odb UNUSED,
+			 const void *buf, unsigned long len,
+			 enum object_type type,
+			 struct object_id *oid,
+			 struct object_id *compat_oid,
+			 unsigned flags)
+{
+	return write_object_file(buf, len, type, oid, compat_oid, flags);
+}
+
 struct object_database *odb_new(struct repository *repo)
 {
 	struct object_database *o = xmalloc(sizeof(*o));

odb.h

@@ -437,6 +437,44 @@ enum for_each_object_flags {
 	FOR_EACH_OBJECT_SKIP_ON_DISK_KEPT_PACKS = (1<<4),
 };
 
+enum {
+	/*
+	 * By default, `odb_write_object()` does not actually write anything
+	 * into the object store, but only computes the object ID. This flag
+	 * changes that so that the object will be written as a loose object
+	 * and persisted.
+	 */
+	WRITE_OBJECT_PERSIST = (1 << 0),
+
+	/*
+	 * Do not print an error in case something goes wrong.
+	 */
+	WRITE_OBJECT_SILENT = (1 << 1),
+};
+
+/*
+ * Write an object into the object database. The object is being written into
+ * the local alternate of the repository. If provided, the converted object ID
+ * as well as the compatibility object ID are written to the respective
+ * pointers.
+ *
+ * Returns 0 on success, a negative error code otherwise.
+ */
+int odb_write_object_ext(struct object_database *odb,
+			 const void *buf, unsigned long len,
+			 enum object_type type,
+			 struct object_id *oid,
+			 struct object_id *compat_oid,
+			 unsigned flags);
+
+static inline int odb_write_object(struct object_database *odb,
+				   const void *buf, unsigned long len,
+				   enum object_type type,
+				   struct object_id *oid)
+{
+	return odb_write_object_ext(odb, buf, len, type, oid, NULL, 0);
+}
+
 /* Compatibility wrappers, to be removed once Git 2.51 has been released. */
 #include "repository.h"
 

read-cache.c

@@ -690,7 +690,7 @@ static struct cache_entry *create_alias_ce(struct index_state *istate,
 void set_object_name_for_intent_to_add_entry(struct cache_entry *ce)
 {
 	struct object_id oid;
-	if (write_object_file("", 0, OBJ_BLOB, &oid))
+	if (odb_write_object(the_repository->objects, "", 0, OBJ_BLOB, &oid))
 		die(_("cannot create an empty blob in the object database"));
 	oidcpy(&ce->oid, &oid);
 }