chore: import upstream snapshot with attribution

server/tables/virtual_table.go

@@ -0,0 +1,117 @@
+// Copyright 2024 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package tables
+
+import (
+	"github.com/cockroachdb/errors"
+	"github.com/dolthub/go-mysql-server/sql"
+)
+
+// VirtualTable represents a table that does not enforce any particular storage of its data.
+type VirtualTable struct {
+	handler     Handler
+	schema      sql.DatabaseSchema
+	indexLookup sql.IndexLookup
+}
+
+var _ sql.DebugStringer = (*VirtualTable)(nil)
+var _ sql.PrimaryKeyTable = (*VirtualTable)(nil)
+var _ sql.Table = (*VirtualTable)(nil)
+var _ sql.DatabaseSchemaTable = (*VirtualTable)(nil)
+var _ sql.IndexAddressableTable = (*VirtualTable)(nil)
+var _ sql.IndexedTable = (*VirtualTable)(nil)
+
+// NewVirtualTable creates a new *VirtualTable from the given Handler.
+func NewVirtualTable(handler Handler, schema sql.DatabaseSchema) *VirtualTable {
+	return &VirtualTable{
+		handler: handler,
+		schema:  schema,
+	}
+}
+
+// Collation implements the interface sql.Table.
+func (tbl *VirtualTable) Collation() sql.CollationID {
+	return sql.Collation_Default
+}
+
+// DebugString implements the interface sql.DebugStringer.
+func (tbl *VirtualTable) DebugString(ctx *sql.Context) string {
+	return "virt_table_" + tbl.String()
+}
+
+// Name implements the interface sql.Table.
+func (tbl *VirtualTable) Name() string {
+	return tbl.handler.Name()
+}
+
+// PartitionRows implements the interface sql.Table.
+func (tbl *VirtualTable) PartitionRows(ctx *sql.Context, partition sql.Partition) (sql.RowIter, error) {
+	return tbl.handler.RowIter(ctx, partition)
+}
+
+// Partitions implements the interface sql.Table.
+func (tbl *VirtualTable) Partitions(ctx *sql.Context) (sql.PartitionIter, error) {
+	return &partitionIter{
+		used: false,
+	}, nil
+}
+
+// PrimaryKeySchema implements the interface sql.PrimaryKeyTable.
+func (tbl *VirtualTable) PrimaryKeySchema(ctx *sql.Context) sql.PrimaryKeySchema {
+	return tbl.handler.PkSchema()
+}
+
+// Schema implements the interface sql.Table.
+func (tbl *VirtualTable) Schema(ctx *sql.Context) sql.Schema {
+	return tbl.PrimaryKeySchema(ctx).Schema
+}
+
+// String implements the interface sql.Table.
+func (tbl *VirtualTable) String() string {
+	return tbl.Name()
+}
+
+func (tbl *VirtualTable) DatabaseSchema() sql.DatabaseSchema {
+	return tbl.schema
+}
+
+// IndexedAccess implements the interface sql.IndexAddressableTable.
+func (tbl *VirtualTable) IndexedAccess(ctx *sql.Context, lookup sql.IndexLookup) sql.IndexedTable {
+	ntbl := *tbl
+	ntbl.indexLookup = lookup
+	return &ntbl
+}
+
+// GetIndexes implements the interface sql.IndexedTable.
+func (tbl *VirtualTable) GetIndexes(ctx *sql.Context) ([]sql.Index, error) {
+	if itbl, ok := tbl.handler.(IndexedTableHandler); ok {
+		return itbl.Indexes()
+	}
+	return nil, nil
+}
+
+// GetIndexLookup implements the interface sql.IndexAddressableTable.
+func (tbl *VirtualTable) PreciseMatch() bool {
+	// TODO: make this configurable per table
+	return true
+}
+
+// LookupPartitions implements the interface sql.IndexedTable.
+func (tbl *VirtualTable) LookupPartitions(ctx *sql.Context, lookup sql.IndexLookup) (sql.PartitionIter, error) {
+	if itbl, ok := tbl.handler.(IndexedTableHandler); ok {
+		return itbl.LookupPartitions(ctx, lookup)
+	}
+	return nil, errors.Errorf("cannot lookup partitions for virtual table %s", tbl.Name())
+}