Make sure to use the checked possibly-nil pointer in memdb

Signed-off-by: Joseph Schorr <josephschorr@users.noreply.github.com>
authzed · Oct 14, 2021 · df88351 · df88351
1 parent d926ca4
commit df88351
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Showing 4 changed files with 39 additions and 20 deletions.
diff --git a/internal/datastore/memdb/namespace.go b/internal/datastore/memdb/namespace.go
@@ -19,11 +19,12 @@ const (
 )
 
 func (mds *memdbDatastore) WriteNamespace(ctx context.Context, newConfig *v0.NamespaceDefinition) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(true)
+	txn := db.Txn(true)
 	defer txn.Abort()
 
 	time.Sleep(mds.simulatedLatency)
@@ -79,11 +80,12 @@ func (mds *memdbDatastore) WriteNamespace(ctx context.Context, newConfig *v0.Nam
 
 // ReadNamespace reads a namespace definition and version and returns it if found.
 func (mds *memdbDatastore) ReadNamespace(ctx context.Context, nsName string) (*v0.NamespaceDefinition, datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return nil, datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(false)
+	txn := db.Txn(false)
 	defer txn.Abort()
 
 	time.Sleep(mds.simulatedLatency)
@@ -107,11 +109,12 @@ func (mds *memdbDatastore) ReadNamespace(ctx context.Context, nsName string) (*v
 }
 
 func (mds *memdbDatastore) DeleteNamespace(ctx context.Context, nsName string) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(true)
+	txn := db.Txn(true)
 	defer txn.Abort()
 
 	time.Sleep(mds.simulatedLatency)
@@ -165,13 +168,14 @@ func (mds *memdbDatastore) DeleteNamespace(ctx context.Context, nsName string) (
 }
 
 func (mds *memdbDatastore) ListNamespaces(ctx context.Context) ([]*v0.NamespaceDefinition, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return nil, fmt.Errorf("memdb closed")
 	}
 
 	var nsDefs []*v0.NamespaceDefinition
 
-	txn := mds.db.Txn(false)
+	txn := db.Txn(false)
 	defer txn.Abort()
 
 	it, err := txn.Get(tableNamespaceConfig, indexID)

diff --git a/internal/datastore/memdb/query.go b/internal/datastore/memdb/query.go
@@ -95,11 +95,12 @@ func iteratorForFilter(txn *memdb.Txn, filter *v1.RelationshipFilter) (memdb.Res
 }
 
 func (mtq memdbTupleQuery) Execute(ctx context.Context) (datastore.TupleIterator, error) {
-	if mtq.db == nil {
+	db := mtq.db
+	if db == nil {
 		return nil, fmt.Errorf("memdb closed")
 	}
 
-	txn := mtq.db.Txn(false)
+	txn := db.Txn(false)
 
 	time.Sleep(mtq.simulatedLatency)
 

diff --git a/internal/datastore/memdb/reverse_query.go b/internal/datastore/memdb/reverse_query.go
@@ -39,7 +39,12 @@ func (mtq memdbReverseTupleQuery) WithObjectRelation(namespaceName string, relat
 }
 
 func (mtq memdbReverseTupleQuery) Execute(ctx context.Context) (datastore.TupleIterator, error) {
-	txn := mtq.db.Txn(false)
+	db := mtq.db
+	if db == nil {
+		return nil, fmt.Errorf("memdb closed")
+	}
+
+	txn := db.Txn(false)
 
 	time.Sleep(mtq.simulatedLatency)
 

diff --git a/internal/datastore/memdb/tuple.go b/internal/datastore/memdb/tuple.go
@@ -50,11 +50,12 @@ func (mds *memdbDatastore) checkPrecondition(txn *memdb.Txn, preconditions []*v1
 }
 
 func (mds *memdbDatastore) WriteTuples(ctx context.Context, preconditions []*v1.Precondition, mutations []*v1.RelationshipUpdate) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(true)
+	txn := db.Txn(true)
 	defer txn.Abort()
 
 	if err := mds.checkPrecondition(txn, preconditions); err != nil {
@@ -137,11 +138,12 @@ func (mds *memdbDatastore) write(ctx context.Context, txn *memdb.Txn, mutations
 }
 
 func (mds *memdbDatastore) DeleteRelationships(ctx context.Context, preconditions []*v1.Precondition, filter *v1.RelationshipFilter) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(true)
+	txn := db.Txn(true)
 	defer txn.Abort()
 
 	if err := mds.checkPrecondition(txn, preconditions); err != nil {
@@ -221,12 +223,13 @@ func (mds *memdbDatastore) ReverseQueryTuplesFromSubjectNamespace(subjectNamespa
 }
 
 func (mds *memdbDatastore) SyncRevision(ctx context.Context) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
 	// Compute the current revision
-	txn := mds.db.Txn(false)
+	txn := db.Txn(false)
 	defer txn.Abort()
 
 	lastRaw, err := txn.Last(tableChangelog, indexID)
@@ -240,11 +243,12 @@ func (mds *memdbDatastore) SyncRevision(ctx context.Context) (datastore.Revision
 }
 
 func (mds *memdbDatastore) Revision(ctx context.Context) (datastore.Revision, error) {
-	if mds.db == nil {
+	db := mds.db
+	if db == nil {
 		return datastore.NoRevision, fmt.Errorf("memdb closed")
 	}
 
-	txn := mds.db.Txn(false)
+	txn := db.Txn(false)
 	defer txn.Abort()
 
 	lowerBound := uint64(time.Now().Add(-1 * mds.revisionFuzzingTimedelta).UnixNano())
@@ -267,7 +271,12 @@ func (mds *memdbDatastore) Revision(ctx context.Context) (datastore.Revision, er
 }
 
 func (mds *memdbDatastore) CheckRevision(ctx context.Context, revision datastore.Revision) error {
-	txn := mds.db.Txn(false)
+	db := mds.db
+	if db == nil {
+		return fmt.Errorf("memdb closed")
+	}
+
+	txn := db.Txn(false)
 	defer txn.Abort()
 
 	// We need to know the highest possible revision