Added a generic text array codec that supports the delimiter value, k…

…nown to pgcatalog, when parsing the text representation of an array

spi/pgtypes/enhanced_array_text_codec.go

@@ -0,0 +1,153 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 pgtypes
+
+import (
+ "database/sql/driver"
+ "github.com/jackc/pgx/v5/pgtype"
+ "strings"
+)
+
+func EnhancedArrayTextCodecFactory[V any](
+ typeMap *pgtype.Map, typ PgType,
+) pgtype.Codec {
+
+ if pt, present := typeMap.TypeForOID(typ.OidElement()); present {
+ scanPlan := typeMap.PlanScan(typ.OidElement(), pgtype.TextFormatCode, new(V))
+ return &EnhancedArrayTextCodec[V]{
+ PgxArrayCodec: &pgtype.ArrayCodec{ElementType: pt},
+ oid: typ.Oid(),
+ oidElem: typ.OidElement(),
+ delimiter: typ.Delimiter(),
+ cachedScanPlan: scanPlan,
+ planValueType: *new(V),
+ }
+ }
+ return nil
+}
+
+// EnhancedArrayTextCodec is an enhanced array codec utilizing the
+// typdelim field from pg_type as a separator of the text value
+// representing the array in the PG wire protocol. The pgx internal
+// implementation always expects the delimiter to be a comma (,)
+// which isn't true for all types, such as box, and PostGIS types.
+//
+// This special version only implements text format, binary is
+// forwarded to the original array codec, as it doesn't have the
+// same issue, since it's a text parsing issue only.
+type EnhancedArrayTextCodec[V any] struct {
+ PgxArrayCodec *pgtype.ArrayCodec
+ oid uint32
+ oidElem uint32
+ delimiter string
+ cachedScanPlan pgtype.ScanPlan
+ planValueType V
+}
+
+func (c *EnhancedArrayTextCodec[V]) FormatSupported(
+ format int16,
+) bool {
+
+ if format == pgtype.TextFormatCode {
+ return true
+ }
+ return c.PgxArrayCodec.FormatSupported(format)
+}
+
+func (c *EnhancedArrayTextCodec[V]) PreferredFormat() int16 {
+ return c.PgxArrayCodec.PreferredFormat()
+}
+
+func (c *EnhancedArrayTextCodec[V]) PlanEncode(
+ m *pgtype.Map, oid uint32, format int16, value any,
+) pgtype.EncodePlan {
+
+ return c.PgxArrayCodec.PlanEncode(m, oid, format, value)
+}
+
+func (c *EnhancedArrayTextCodec[V]) PlanScan(
+ m *pgtype.Map, oid uint32, format int16, target any,
+) pgtype.ScanPlan {
+
+ if oid == c.oid && format == pgtype.TextFormatCode {
+ return &scanPlanEnhancedArrayTextCodec[V]{
+ typeMap: m,
+ oidElem: c.oidElem,
+ delimiter: c.delimiter,
+ planValueType: c.planValueType,
+ cachedScanPlan: c.cachedScanPlan,
+ }
+ }
+
+ return c.PgxArrayCodec.PlanScan(m, oid, format, target)
+}
+
+func (c *EnhancedArrayTextCodec[V]) DecodeDatabaseSQLValue(
+ m *pgtype.Map, oid uint32, format int16, src []byte,
+) (driver.Value, error) {
+
+ return c.PgxArrayCodec.DecodeDatabaseSQLValue(m, oid, format, src)
+}
+
+func (c *EnhancedArrayTextCodec[V]) DecodeValue(
+ m *pgtype.Map, oid uint32, format int16, src []byte,
+) (any, error) {
+
+ if src == nil {
+ return nil, nil
+ }
+
+ if format == pgtype.TextFormatCode {
+ var slice []V
+ err := m.PlanScan(oid, format, &slice).Scan(src, &slice)
+ return slice, err
+ }
+
+ return c.PgxArrayCodec.DecodeValue(m, oid, format, src)
+}
+
+type scanPlanEnhancedArrayTextCodec[V any] struct {
+ cachedScanPlan pgtype.ScanPlan
+ typeMap *pgtype.Map
+ oidElem uint32
+ delimiter string
+ planValueType V
+}
+
+func (spbac *scanPlanEnhancedArrayTextCodec[V]) Scan(
+ src []byte, dst any,
+) error {
+
+ array := dst.(*[]V)
+
+ scanPlan := spbac.cachedScanPlan
+ if scanPlan == nil {
+ scanPlan = spbac.typeMap.PlanScan(spbac.oidElem, pgtype.TextFormatCode, &spbac.planValueType)
+ }
+
+ // Semicolon seems to be the separator here
+ elements := strings.Split(string(src[1:len(src)-1]), spbac.delimiter)
+ for _, element := range elements {
+ item := new(V)
+ if err := scanPlan.Scan([]byte(element), item); err != nil {
+ return err
+ }
+ *array = append(*array, *item)
+ }
+ return nil
+}