Make hashcodes produced by TDirectObjectIdHash truely 64 bit

2de4b05f986a03156d6a56a6e660777764fcc52f

4 files changed, 29 insertions, 30 deletions

diff --git a/yt/yt/client/chaos_client/helpers.cpp b/yt/yt/client/chaos_client/helpers.cpp
index 377011c913..8f7a289c34 100644
--- a/yt/yt/client/chaos_client/helpers.cpp
+++ b/yt/yt/client/chaos_client/helpers.cpp
@@ -18,7 +18,7 @@ TReplicationCardId MakeReplicationCardId(TObjectId randomId)
         EObjectType::ReplicationCard,
         CellTagFromId(randomId),
         CounterFromId(randomId),
-        HashFromId(randomId) & 0xffff0000);
+        EntropyFromId(randomId) & 0xffff0000);
 }
 
 TReplicaId MakeReplicaId(TReplicationCardId replicationCardId, TReplicaIdIndex index)
@@ -27,7 +27,7 @@ TReplicaId MakeReplicaId(TReplicationCardId replicationCardId, TReplicaIdIndex i
         EObjectType::ChaosTableReplica,
         CellTagFromId(replicationCardId),
         CounterFromId(replicationCardId),
-        HashFromId(replicationCardId) | index);
+        EntropyFromId(replicationCardId) | index);
 }
 
 TReplicationCardId ReplicationCardIdFromReplicaId(TReplicaId replicaId)
@@ -36,7 +36,7 @@ TReplicationCardId ReplicationCardIdFromReplicaId(TReplicaId replicaId)
         EObjectType::ReplicationCard,
         CellTagFromId(replicaId),
         CounterFromId(replicaId),
-        HashFromId(replicaId) & 0xffff0000);
+        EntropyFromId(replicaId) & 0xffff0000);
 }
 
 TReplicationCardId ReplicationCardIdFromUpstreamReplicaIdOrNull(TReplicaId upstreamReplicaId)
@@ -52,7 +52,7 @@ TReplicationCardId MakeReplicationCardCollocationId(TObjectId randomId)
         EObjectType::ReplicationCardCollocation,
         CellTagFromId(randomId),
         CounterFromId(randomId),
-        HashFromId(randomId) & 0xffff0000);
+        EntropyFromId(randomId) & 0xffff0000);
 }
 
 TCellTag GetSiblingChaosCellTag(TCellTag cellTag)
diff --git a/yt/yt/client/object_client/helpers-inl.h b/yt/yt/client/object_client/helpers-inl.h
index 9297fec91d..1aaa08b251 100644
--- a/yt/yt/client/object_client/helpers-inl.h
+++ b/yt/yt/client/object_client/helpers-inl.h
@@ -29,7 +29,7 @@ inline ui64 CounterFromId(TObjectId id)
     return result;
 }
 
-inline ui32 HashFromId(TObjectId id)
+inline ui32 EntropyFromId(TObjectId id)
 {
     return id.Parts32[0];
 }
@@ -62,10 +62,10 @@ inline TObjectId MakeId(
     EObjectType type,
     TCellTag cellTag,
     ui64 counter,
-    ui32 hash)
+    ui32 entropy)
 {
     return TObjectId(
-        hash,
+        entropy,
         (static_cast<ui32>(cellTag.Underlying()) << 16) | static_cast<ui32>(type),
         counter & 0xffffffff,
         counter >> 32);
@@ -97,10 +97,10 @@ inline TObjectId MakeRegularId(
     EObjectType type,
     TCellTag cellTag,
     NHydra::TVersion version,
-    ui32 hash)
+    ui32 entropy)
 {
     return TObjectId(
-        hash,
+        entropy,
         (static_cast<ui32>(cellTag.Underlying()) << 16) | static_cast<ui32>(type),
         version.RecordId,
         version.SegmentId);
@@ -110,14 +110,14 @@ inline TObjectId MakeSequoiaId(
     EObjectType type,
     TCellTag cellTag,
     NTransactionClient::TTimestamp timestamp,
-    ui32 hash)
+    ui32 entropy)
 {
     YT_ASSERT(!(timestamp & SequoiaCounterMask));
     return MakeId(
         type,
         cellTag,
         timestamp | SequoiaCounterMask,
-        hash);
+        entropy);
 }
 
 inline TObjectId MakeWellKnownId(
@@ -163,22 +163,21 @@ inline TObjectId ReplaceCellTagInId(
 template <int ShardCount>
 inline int GetShardIndex(TObjectId id)
 {
-    static_assert(IsPowerOf2(ShardCount), "Number of shards must be a power of 2");
-    return TDirectObjectIdHash()(id) & (ShardCount - 1);
+    return EntropyFromId(id) % static_cast<ui32>(ShardCount);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
-Y_FORCE_INLINE size_t TDirectObjectIdHash::operator()(TObjectId id) const
+Y_FORCE_INLINE size_t TObjectIdEntropyHash::operator()(TObjectId id) const
 {
-    return id.Parts32[0];
+    return (static_cast<size_t>(id.Parts32[0]) | (static_cast<size_t>(id.Parts32[0]) << 32)) ^ id.Parts64[1];
 }
 
-Y_FORCE_INLINE size_t TDirectVersionedObjectIdHash::operator()(const TVersionedObjectId& id) const
+Y_FORCE_INLINE size_t TVersionedObjectIdEntropyHash::operator()(const TVersionedObjectId& id) const
 {
     return
-        TDirectObjectIdHash()(id.TransactionId) * 497 +
-        TDirectObjectIdHash()(id.ObjectId);
+        TObjectIdEntropyHash()(id.TransactionId) * 497 +
+        TObjectIdEntropyHash()(id.ObjectId);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/yt/yt/client/object_client/helpers.h b/yt/yt/client/object_client/helpers.h
index a258269afe..d172d8b45c 100644
--- a/yt/yt/client/object_client/helpers.h
+++ b/yt/yt/client/object_client/helpers.h
@@ -84,8 +84,8 @@ TCellTag CellTagFromId(TObjectId id);
 //! Extracts the counter component from #id.
 ui64 CounterFromId(TObjectId id);
 
-//! Extracts the hash component from #id.
-ui32 HashFromId(TObjectId id);
+//! Extracts the entropy component from #id.
+ui32 EntropyFromId(TObjectId id);
 
 //! Extracts Hydra revision from #id for non-Sequoia objects.
 NHydra::TVersion VersionFromId(TObjectId id);
@@ -110,7 +110,7 @@ TObjectId MakeId(
     EObjectType type,
     TCellTag cellTag,
     ui64 counter,
-    ui32 hash);
+    ui32 entropy);
 
 //! Creates a random id with given type and cell tag.
 TObjectId MakeRandomId(
@@ -134,14 +134,14 @@ TObjectId MakeRegularId(
     EObjectType type,
     TCellTag cellTag,
     NHydra::TVersion version,
-    ui32 hash);
+    ui32 entropy);
 
 //! Constructs the id for a regular Sequoia object.
 TObjectId MakeSequoiaId(
     EObjectType type,
     TCellTag cellTag,
     NTransactionClient::TTimestamp timestamp,
-    ui32 hash);
+    ui32 entropy);
 
 //! Constructs the id corresponding to well-known (usually singleton) entities.
 /*
@@ -178,15 +178,15 @@ bool IsGlobalCellId(TCellId cellId);
 
 ////////////////////////////////////////////////////////////////////////////////
 
-//! Relies on first 32 bits of object id to be pseudo-random,
-//! cf. TObjectManager::GenerateId.
-struct TDirectObjectIdHash
+//! Relies on first 32 bits of object id ("entropy") to be pseudo-random,
+//! cf. MakeRegularId.
+struct TObjectIdEntropyHash
 {
     size_t operator()(TObjectId id) const;
 };
 
-//! Cf. TDirectObjectIdHash
-struct TDirectVersionedObjectIdHash
+//! Cf. TObjectIdEntropyHash
+struct TVersionedObjectIdEntropyHash
 {
     size_t operator()(const TVersionedObjectId& id) const;
 };
diff --git a/yt/yt/client/object_client/public.h b/yt/yt/client/object_client/public.h
index 28536c9516..bdb18fa02d 100644
--- a/yt/yt/client/object_client/public.h
+++ b/yt/yt/client/object_client/public.h
@@ -409,8 +409,8 @@ bool operator <  (const TVersionedObjectId& lhs, const TVersionedObjectId& rhs);
 
 class TObjectServiceProxy;
 
-struct TDirectObjectIdHash;
-struct TDirectVersionedObjectIdHash;
+struct TObjectIdEntropyHash;
+struct TVersionedObjectIdEntropyHash;
 
 ////////////////////////////////////////////////////////////////////////////////