Re: [PATCH 05/10] odb: provide infrastructure for pluggable fsck checks

The on-disk consistency checks in git-fsck(1) are conceptually
backend-specific: while connectivity checks and object-level parsing
checks are generic, verifying the physical integrity of packfiles and
loose objects is meaningful only to backends that use these formats:
Having these checks live in "builtin/fsck.c" violates that layering,
because it forces the command to reach directly into format-specific
internals.

Provide new infrastructure to make these format-specific checks
pluggable and implement stubs for the different source types we already
have. In subsequent commits we'll move functionality over piece by
piece.

Signed-off-by: Patrick Steinhardt <redacted>
---
 builtin/fsck.c        | 16 +++++++++++-----
 odb.c                 |  9 +++++++++
 odb.h                 | 23 +++++++++++++++++++++++
 odb/source-files.c    | 13 +++++++++++++
 odb/source-inmemory.c |  8 ++++++++
 odb/source-loose.c    |  7 +++++++
 odb/source-packed.c   |  8 ++++++++
 odb/source.h          | 21 +++++++++++++++++++++
 8 files changed, 100 insertions(+), 5 deletions(-)

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 3f6056535f..adbe192e56 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c

@@ -965,7 +965,9 @@ int cmd_fsck(int argc,
 	     const char *prefix,
 	     struct repository *repo)
 {
-	int check_full = 1;
+	struct odb_fsck_options odb_fsck_opts = {
+		.flags = ODB_FSCK_FULL,
+	};
 	int keep_cache_objects = 0;
 	int name_objects = 0;
 	int check_references = 1;

@@ -977,7 +979,8 @@ int cmd_fsck(int argc,
 		OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
 		OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
 		OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
-		OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),

+		OPT_BIT(0, "full", &odb_fsck_opts.flags,
+			N_("also consider packs and alternate objects"), ODB_FSCK_FULL),
 		OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
 		OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
 		OPT_BOOL(0, "lost-found", &write_lost_and_found,

@@ -1018,7 +1021,7 @@ int cmd_fsck(int argc,
 		show_progress = 0;

 	if (write_lost_and_found) {
-		check_full = 1;
+		odb_fsck_opts.flags |= ODB_FSCK_FULL;
 		include_reflogs = 0;
 	}

@@ -1047,10 +1050,13 @@ int cmd_fsck(int argc,
 				    mark_object_for_connectivity, repo, 0);
 	} else {
 		for (source = repo->objects->sources; source; source = source->next)
-			if (check_full || source->local)
+			if ((odb_fsck_opts.flags & ODB_FSCK_FULL) || source->local)
 				fsck_source(repo, source);

-		if (check_full) {
+		if (odb_fsck(repo->objects, &odb_fsck_opts) < 0)
+			errors_found |= ERROR_OBJECT;
+

+		if (odb_fsck_opts.flags & ODB_FSCK_FULL) {
 			struct packed_git *p;
 			uint32_t total = 0, count = 0;
 			struct progress *progress = NULL;

diff --git a/odb.c b/odb.c
index 1fe20808eb..766043b685 100644
--- a/odb.c
+++ b/odb.c

@@ -1177,3 +1177,12 @@ void odb_reprepare(struct object_database *o)
 {
 	odb_prepare(o, ODB_PREPARE_FLUSH_CACHES);
 }
+
+int odb_fsck(struct object_database *odb, struct odb_fsck_options *options)
+{
+	int ret = 0;
+	for (struct odb_source *source = odb->sources; source; source = source->next)
+		if ((options->flags & ODB_FSCK_FULL) || source->local)
+			ret |= odb_source_fsck(source, options);
+	return ret;
+}