lint

FerretDB · AlekSi · Oct 9, 2023 · Sep 29, 2023 · Sep 29, 2023 · Sep 29, 2023
commit 2dd28582961ff03c4b5a338e812c757ba85e57aa
@@ -58,7 +58,7 @@
 
 	if p == nil {
 		return &backends.QueryResult{
-			Iter: newQueryIterator(ctx, nil, nil),
+			Iter: newQueryIterator(ctx, &iteratorParams{}),
 		}, nil
 	}
 
@@ -69,7 +69,7 @@
 
 	if meta == nil {
 		return &backends.QueryResult{
-			Iter: newQueryIterator(ctx, nil, nil),
+			Iter: newQueryIterator(ctx, &iteratorParams{}),
 		}, nil
 	}
 
@@ -86,7 +86,9 @@
 	}
 
 	return &backends.QueryResult{
-		Iter: newQueryIterator(ctx, rows, nil),
+		Iter: newQueryIterator(ctx, &iteratorParams{
+			rows: rows,
+		}),
 	}, nil
 }
 
@@ -246,49 +248,53 @@

 // Explain implements backends.Collection interface.
 func (c *collection) Explain(ctx context.Context, params *backends.ExplainParams) (*backends.ExplainResult, error) {
 	p, err := c.r.DatabaseGetExisting(ctx, c.dbName)
 	if err != nil {
 		return nil, lazyerrors.Error(err)
 	}

 	if p == nil {
 		return &backends.ExplainResult{}, nil
 	}

 	meta, err := c.r.CollectionGet(ctx, c.dbName, c.name)
 	if err != nil {
 		return nil, lazyerrors.Error(err)
 	}

 	if meta == nil {
 		return &backends.ExplainResult{
 			QueryPlanner: must.NotFail(types.NewDocument()),
 		}, nil
 	}

 	// TODO https://github.com/FerretDB/FerretDB/issues/3414
 	q := fmt.Sprintf(
 		`EXPLAIN (VERBOSE true, FORMAT JSON) SELECT %s FROM %s`,
 		metadata.DefaultColumn,
 		pgx.Identifier{c.dbName, meta.TableName}.Sanitize(),
 	)

 	rows, err := p.Query(ctx, q)
 	if err != nil {
 		return nil, lazyerrors.Error(err)
 	}
 
-	iter := newQueryIterator(ctx, rows, unmarshalExplain)
+	iter := newQueryIterator(ctx, &iteratorParams{
+		rows:      rows,
+		unmarshal: unmarshalExplain,
+	})
+
 	defer iter.Close()
 
 	_, queryPlan, err := iter.Next()
 	if err != nil {
 		return nil, lazyerrors.Error(err)
 	}

 	return &backends.ExplainResult{
 		QueryPlanner: must.NotFail(types.NewDocument("Plan", queryPlan)),
 	}, nil
 }

 // Stats implements backends.Collection interface.

diff --git a/internal/backends/postgresql/query_iterator.go b/internal/backends/postgresql/query_iterator.go
@@ -40,6 +40,12 @@
 	m     sync.Mutex
 }
 
+// iteratorParams contains parameters for building an iterator.
+type iteratorParams struct {
+	rows      pgx.Rows
+	unmarshal func(b []byte) (*types.Document, error) // if set, iterator uses unmarshal to convert row to *types.Document.
+}
+
 // newQueryIterator returns a new queryIterator for the given Rows.
 //
 // Iterator's Close method closes rows.
@@ -49,16 +55,16 @@
 //
 // Nil rows are possible and return already done iterator.
 // It still should be Close'd.
-func newQueryIterator(ctx context.Context, rows pgx.Rows, unmarshal func(b []byte) (*types.Document, error)) types.DocumentsIterator {
-	if unmarshal == nil {
-		unmarshal = sjson.Unmarshal
+func newQueryIterator(ctx context.Context, params *iteratorParams) types.DocumentsIterator {
+	if params.unmarshal == nil {
+		params.unmarshal = sjson.Unmarshal
 	}
 
 	iter := &queryIterator{
 		ctx:       ctx,
-		rows:      rows,
+		rows:      params.rows,
 		token:     resource.NewToken(),
-		unmarshal: unmarshal,
+		unmarshal: params.unmarshal,
 	}
 	resource.Track(iter, iter.token)
 
@@ -102,7 +108,7 @@
 		return unused, nil, lazyerrors.Error(err)
 	}

 	doc, err := iter.unmarshal(b)
 	if err != nil {
 		iter.close()
 		return unused, nil, lazyerrors.Error(err)