object-file: refactor writing objects via a stream

We have two different ways to write an object into the database: - We either provide the full buffer and write the object all at once. - Or we provide an input stream that has a `read()` function so that we can chunk the object. The latter is especially used for large objects, where it may be too expensive to hold the complete object in memory all at once. While we already have `odb_write_object()` at the ODB-layer, we don't have an equivalent for streaming an object. Introduce a new function `odb_write_object_stream()` to address this gap so that callers don't have to be aware of the inner workings of how to stream an object to disk with a specific object source. Rename `stream_loose_object()` to `odb_source_loose_write_stream()` to clarify its scope. This matches our modern best practices around how to name functions. Signed-off-by: Patrick Steinhardt <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

builtin/unpack-objects.c

@@ -363,7 +363,7 @@ struct input_zstream_data{
 intstatus;
 };
 
-staticconstvoid*feed_input_zstream(structinput_stream*in_stream,
+staticconstvoid*feed_input_zstream(structodb_write_stream*in_stream,
 unsigned long*readlen)
 {
 structinput_zstream_data*data=in_stream->data;
@@ -393,7 +393,7 @@ static void stream_blob(unsigned long size, unsigned nr)
 {
 git_zstreamzstream={0 };
 structinput_zstream_datadata={0 };
-structinput_streamin_stream={
+structodb_write_streamin_stream={
  .read=feed_input_zstream,
  .data=&data,
  };
@@ -402,8 +402,7 @@ static void stream_blob(unsigned long size, unsigned nr)
 data.zstream=&zstream;
 git_inflate_init(&zstream);
 
-if (stream_loose_object(the_repository->objects->sources,
-&in_stream, size, &info->oid))
+if (odb_write_object_stream(the_repository->objects, &in_stream, size, &info->oid))
 die(_("failed to write object in stream"));
 
 if (data.status!=Z_STREAM_END)

object-file.c

@@ -974,9 +974,9 @@ int odb_source_loose_freshen_object(struct odb_source *source,
 return !!check_and_freshen_source(source, oid, 1);
 }
 
-intstream_loose_object(structodb_source*source,
-structinput_stream*in_stream, size_tlen,
-structobject_id*oid)
+intodb_source_loose_write_stream(structodb_source*source,
+structodb_write_stream*in_stream, size_tlen,
+structobject_id*oid)
 {
 conststructgit_hash_algo*compat=source->odb->repo->compat_hash_algo;
 structobject_idcompat_oid;

object-file.h

@@ -67,6 +67,10 @@ int odb_source_loose_write_object(struct odb_source *source,
 enumobject_typetype, structobject_id*oid,
 structobject_id*compat_oid_in, unsignedflags);
 
+intodb_source_loose_write_stream(structodb_source*source,
+structodb_write_stream*stream, size_tlen,
+structobject_id*oid);
+
 /*
  * Populate and return the loose object cache array corresponding to the
  * given object ID.
@@ -173,16 +177,6 @@ enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
 structobject_info;
 intparse_loose_header(constchar*hdr, structobject_info*oi);
 
-structinput_stream{
-constvoid*(*read)(structinput_stream*, unsigned long*len);
-void*data;
-intis_finished;
-};
-
-intstream_loose_object(structodb_source*source,
-structinput_stream*in_stream, size_tlen,
-structobject_id*oid);
-
 intforce_object_loose(structodb_source*source,
 conststructobject_id*oid, time_tmtime);
 

odb.c

@@ -1025,6 +1025,13 @@ int odb_write_object_ext(struct object_database *odb,
 oid, compat_oid, flags);
 }
 
+intodb_write_object_stream(structobject_database*odb,
+structodb_write_stream*stream, size_tlen,
+structobject_id*oid)
+{
+returnodb_source_loose_write_stream(odb->sources, stream, len, oid);
+}
+
 structobject_database*odb_new(structrepository*repo)
 {
 structobject_database*o=xmalloc(sizeof(*o));

odb.h

@@ -492,4 +492,14 @@ static inline int odb_write_object(struct object_database *odb,
 returnodb_write_object_ext(odb, buf, len, type, oid, NULL, 0);
 }
 
+structodb_write_stream{
+constvoid*(*read)(structodb_write_stream*, unsigned long*len);
+void*data;
+intis_finished;
+};
+
+intodb_write_object_stream(structobject_database*odb,
+structodb_write_stream*stream, size_tlen,
+structobject_id*oid);
+
 #endif/* ODB_H */