MB-51413: Move ReadVBStateStatus to KVStoreIface

We'll use it in getPersistedVBucketState in a future patch to
differentiate between NotFound and Success.

Change-Id: I8432208e0ae12959ab9c8a55848f90a3b81d0d01
Reviewed-on: https://review.couchbase.org/c/kv_engine/+/172254
Reviewed-by: James H <[email protected]>
Tested-by: Build Bot <[email protected]>

Author: BenHuddleston

engines/ep/src/kvstore/couch-kvstore/couch-kvstore.cc

@@ -198,22 +198,6 @@ static std::string getDBFileName(const std::string& dbname,
            std::to_string(rev);
 }
 
-std::string to_string(CouchKVStore::ReadVBStateStatus status) {
-    switch (status) {
-    case CouchKVStore::ReadVBStateStatus::Success:
-        return "Success";
-    case CouchKVStore::ReadVBStateStatus::NotFound:
-        return "NotFound";
-    case CouchKVStore::ReadVBStateStatus::JsonInvalid:
-        return "JsonInvalid";
-    case CouchKVStore::ReadVBStateStatus::CorruptSnapshot:
-        return "CorruptSnapshot";
-    case CouchKVStore::ReadVBStateStatus::CouchstoreError:
-        return "CouchstoreError";
-    }
-    folly::assume_unreachable();
-}
-
 /// @returns the document ID used to store cid
 std::string CouchKVStore::getCollectionStatsLocalDocId(CollectionID cid) {
     return fmt::format("|{:#x}|", uint32_t(cid));
@@ -3309,7 +3293,7 @@ CouchKVStore::ReadVBStateResult CouchKVStore::readVBState(Db* db,
                 " error:{}, {}",
                 couchstore_strerror(couchStoreStatus),
                 vbId);
-        return {ReadVBStateStatus::CouchstoreError, {}};
+        return {ReadVBStateStatus::Error, {}};
     }
 
     // Proceed to read/parse the vbstate

engines/ep/src/kvstore/couch-kvstore/couch-kvstore.h

@@ -150,14 +150,6 @@ class CouchKVStore : public KVStore
     using PendingRequestQueue = std::deque<CouchRequest>;
     using PendingLocalDocRequestQueue = std::deque<CouchLocalDocRequest>;
 
-    enum class ReadVBStateStatus : uint8_t {
-        Success = 0,
-        NotFound,
-        JsonInvalid,
-        CorruptSnapshot,
-        CouchstoreError
-    };
-
     /**
      * Constructor - creates a read/write CouchKVStore
      *
@@ -827,16 +819,6 @@ class CouchKVStore : public KVStore
         concurrentCompactionPreLockHook = std::move(hook);
     }
 
-    /**
-     * Result of the readVBState function
-     */
-    struct ReadVBStateResult {
-        ReadVBStateStatus status{ReadVBStateStatus::Success};
-
-        // Only valid if status == ReadVBStateStatus::Success
-        vbucket_state state;
-    };
-
     /**
      * Read the vbucket_state from disk.
      */
@@ -1065,5 +1047,3 @@ struct CouchKVStoreTransactionContext : public TransactionContext {
      */
     CouchKVStore::PendingLocalDocRequestQueue pendingLocalReqsQ;
 };
-
-std::string to_string(CouchKVStore::ReadVBStateStatus status);

engines/ep/src/kvstore/kvstore.cc

@@ -688,4 +688,20 @@ std::ostream& operator<<(std::ostream& os, ScanStatus status) {
         return os << "ScanStatus::Failed";
     }
     folly::assume_unreachable();
+}
+
+std::string to_string(KVStoreIface::ReadVBStateStatus status) {
+    switch (status) {
+    case KVStoreIface::ReadVBStateStatus::Success:
+        return "Success";
+    case KVStoreIface::ReadVBStateStatus::NotFound:
+        return "NotFound";
+    case KVStoreIface::ReadVBStateStatus::JsonInvalid:
+        return "JsonInvalid";
+    case KVStoreIface::ReadVBStateStatus::CorruptSnapshot:
+        return "CorruptSnapshot";
+    case KVStoreIface::ReadVBStateStatus::Error:
+        return "Error";
+    }
+    folly::assume_unreachable();
 }

engines/ep/src/kvstore/kvstore_iface.h

@@ -15,6 +15,7 @@
 #include "collections/kvstore.h"
 #include "ep_types.h"
 #include "persistence_callback.h"
+#include "vbucket_state.h"
 
 #include <memcached/engine_common.h>
 #include <memcached/thread_pool_config.h>
@@ -37,7 +38,6 @@ struct CompactionConfig;
 struct CompactionContext;
 struct DBFileInfo;
 struct TransactionContext;
-struct vbucket_state;
 
 namespace Collections::VB {
 struct PersistedStats;
@@ -332,6 +332,24 @@ class KVStoreIface {
      */
     virtual vbucket_state* getCachedVBucketState(Vbid vbid) = 0;
 
+    enum class ReadVBStateStatus : uint8_t {
+        Success = 0,
+        NotFound,
+        JsonInvalid,
+        CorruptSnapshot,
+        Error,
+    };
+
+    /**
+     * Result of the readVBState function
+     */
+    struct ReadVBStateResult {
+        ReadVBStateStatus status{ReadVBStateStatus::Success};
+
+        // Only valid if status == ReadVBStateStatus::Success
+        vbucket_state state;
+    };
+
     /**
      * Return the vbucket_state stored on disk for the given vBucket. Does NOT
      * update the cachedVBState.
@@ -739,3 +757,5 @@ class KVStoreIface {
      */
     virtual void prepareToCreateImpl(Vbid vbid) = 0;
 };
+
+std::string to_string(KVStoreIface::ReadVBStateStatus status);