Re: [PATCH 05/17] odb/source: introduce source type for robustness
Patrick Steinhardt <ps@pks.im> writes:
Show 9 quoted lines
> When a caller holds a `struct odb_source`, they have no way of telling
> what type the source is. This doesn't really cause any problems in the
> current status quo as we only have a single type anyway, "files". But
> going forward we expect to add more types, and if so it will become
> necessary to tell the sources apart.
>
> Introduce a new enum to cover this use case and assert that the given
> source actually matches the target source when performing the downcast.
>
So this is what I was talking about in a previous commit, nice to see.
Show 62 quoted lines
> Signed-off-by: Patrick Steinhardt <ps@pks.im>
> ---
> odb/source-files.c | 2 +-
> odb/source-files.h | 2 ++
> odb/source.c | 2 ++
> odb/source.h | 16 ++++++++++++++++
> 4 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/odb/source-files.c b/odb/source-files.c
> index df0ea9ee62..7496e1d9f8 100644
> --- a/odb/source-files.c
> +++ b/odb/source-files.c
> @@ -36,7 +36,7 @@ struct odb_source_files *odb_source_files_new(struct object_database *odb,
> struct odb_source_files *files;
>
> CALLOC_ARRAY(files, 1);
> - odb_source_init(&files->base, odb, path, local);
> + odb_source_init(&files->base, odb, ODB_SOURCE_FILES, path, local);
> files->loose = odb_source_loose_new(&files->base);
> files->packed = packfile_store_new(&files->base);
>
> diff --git a/odb/source-files.h b/odb/source-files.h
> index 58753d40de..803fa995fb 100644
> --- a/odb/source-files.h
> +++ b/odb/source-files.h
> @@ -30,6 +30,8 @@ void odb_source_files_free(struct odb_source_files *files);
> */
> static inline struct odb_source_files *odb_source_files_downcast(struct odb_source *source)
> {
> + if (source->type != ODB_SOURCE_FILES)
> + BUG("trying to downcast source of type '%d' to files", source->type);
> return container_of(source, struct odb_source_files, base);
> }
>
> diff --git a/odb/source.c b/odb/source.c
> index d8b2176a94..c7dcc528f6 100644
> --- a/odb/source.c
> +++ b/odb/source.c
> @@ -13,10 +13,12 @@ struct odb_source *odb_source_new(struct object_database *odb,
>
> void odb_source_init(struct odb_source *source,
> struct object_database *odb,
> + enum odb_source_type type,
> const char *path,
> bool local)
> {
> source->odb = odb;
> + source->type = type;
> source->local = local;
> source->path = xstrdup(path);
> }
> diff --git a/odb/source.h b/odb/source.h
> index e6698b73a3..a1f2f8fdb1 100644
> --- a/odb/source.h
> +++ b/odb/source.h
> @@ -1,6 +1,18 @@
> #ifndef ODB_SOURCE_H
> #define ODB_SOURCE_H
>
> +enum odb_source_type {
> + /*
> + * The "unknown" type, which should never be in use. This is typeShow 33 quoted lines
> + * mostly exists to catch cases where the type field remains zeroed
> + * out.
> + */
> + ODB_SOURCE_UNKNOWN,
> +
> + /* The "files" backend that uses loose objects and packfiles. */
> + ODB_SOURCE_FILES,
> +};
> +
> /*
> * The source is the part of the object database that stores the actual
> * objects. It thus encapsulates the logic to read and write the specific
> @@ -19,6 +31,9 @@ struct odb_source {
> /* Object database that owns this object source. */
> struct object_database *odb;
>
> + /* The type used by this source. */
> + enum odb_source_type type;
> +
> /*
> * Figure out whether this is the local source of the owning
> * repository, which would typically be its ".git/objects" directory.
> @@ -58,6 +73,7 @@ struct odb_source *odb_source_new(struct object_database *odb,
> */
> void odb_source_init(struct odb_source *source,
> struct object_database *odb,
> + enum odb_source_type type,
> const char *path,
> bool local);
>
>
> --
> 2.53.0.536.g309c995771.dirtyKarthik Nayak <karthik.188@gmail.com>