objstorage_checker: Use check method from object storage interface

Instead of reinventing the wheel, prefer to use the check method from the
object storage interface for verifying content presence and integrity.

Related to #4694.

requirements-swh.txt

@@ -4,3 +4,4 @@ swh.loader.git >= 1.4.0
 swh.model >= 5.0.0
 swh.storage >= 2.0.0
 swh.journal >= 1.3.0
+swh.objstorage >= 2.9.2

swh/scrubber/objstorage_checker.py

@@ -12,7 +12,7 @@ from swh.journal.client import get_journal_client
 from swh.journal.serializers import kafka_to_value, value_to_kafka
 from swh.model.model import Content
 from swh.model.swhids import ObjectType
-from swh.objstorage.exc import ObjNotFoundError
+from swh.objstorage.exc import ObjCorruptedError, ObjNotFoundError
 from swh.objstorage.interface import ObjStorageInterface, objid_from_dict
 from swh.storage.interface import StorageInterface
 
@@ -55,25 +55,21 @@ class ContentCheckerMixin(ObjectStorageCheckerProtocol):
 
         content_hashes = objid_from_dict(content.hashes())
         try:
-            content_bytes = self.objstorage.get(content_hashes)
+            self.objstorage.check(content_hashes)
         except ObjNotFoundError:
             if self.config.check_references:
                 self.statsd.increment("missing_object_total")
                 self.db.missing_object_add(
                     id=content.swhid(), reference_ids={}, config=self.config
                 )
-        else:
+        except ObjCorruptedError:
             if self.config.check_hashes:
-                recomputed_hashes = objid_from_dict(
-                    Content.from_data(content_bytes).hashes()
+                self.statsd.increment("hash_mismatch_total")
+                self.db.corrupt_object_add(
+                    id=content.swhid(),
+                    config=self.config,
+                    serialized_object=value_to_kafka(content.to_dict()),
                 )
-                if content_hashes != recomputed_hashes:
-                    self.statsd.increment("hash_mismatch_total")
-                    self.db.corrupt_object_add(
-                        id=content.swhid(),
-                        config=self.config,
-                        serialized_object=value_to_kafka(content.to_dict()),
-                    )
 
 
 class ObjectStorageCheckerFromStoragePartition(