From eb0a4c96264854d3e603eb90536c25104244a6ad Mon Sep 17 00:00:00 2001
From: Jack Christensen <jack@jackchristensen.com>
Date: Sat, 22 Jan 2022 11:21:12 -0600
Subject: [PATCH] Replace some old database/sql compatibility

---
 pgtype/builtin_wrappers.go |  2 ++
 pgtype/database_sql.go     | 41 ----------------------------
 pgtype/pgtype.go           | 56 ++++++++++----------------------------
 3 files changed, 16 insertions(+), 83 deletions(-)
 delete mode 100644 pgtype/database_sql.go

diff --git a/pgtype/builtin_wrappers.go b/pgtype/builtin_wrappers.go
index abf21b82..9df28f55 100644
--- a/pgtype/builtin_wrappers.go
+++ b/pgtype/builtin_wrappers.go
@@ -461,6 +461,8 @@ func (w timeWrapper) TimeValue() (Time, error) {
 
 type durationWrapper time.Duration
 
+func (w durationWrapper) SkipUnderlyingTypePlan() {}
+
 func (w *durationWrapper) ScanInterval(v Interval) error {
 	if !v.Valid {
 		return fmt.Errorf("cannot scan NULL into *time.Interval")
diff --git a/pgtype/database_sql.go b/pgtype/database_sql.go
deleted file mode 100644
index 9d1cf822..00000000
--- a/pgtype/database_sql.go
+++ /dev/null
@@ -1,41 +0,0 @@
-package pgtype
-
-import (
-	"database/sql/driver"
-	"errors"
-)
-
-func DatabaseSQLValue(ci *ConnInfo, src Value) (interface{}, error) {
-	if valuer, ok := src.(driver.Valuer); ok {
-		return valuer.Value()
-	}
-
-	if textEncoder, ok := src.(TextEncoder); ok {
-		buf, err := textEncoder.EncodeText(ci, nil)
-		if err != nil {
-			return nil, err
-		}
-		return string(buf), nil
-	}
-
-	if binaryEncoder, ok := src.(BinaryEncoder); ok {
-		buf, err := binaryEncoder.EncodeBinary(ci, nil)
-		if err != nil {
-			return nil, err
-		}
-		return buf, nil
-	}
-
-	return nil, errors.New("cannot convert to database/sql compatible value")
-}
-
-func EncodeValueText(src TextEncoder) (interface{}, error) {
-	buf, err := src.EncodeText(nil, make([]byte, 0, 32))
-	if err != nil {
-		return nil, err
-	}
-	if buf == nil {
-		return nil, nil
-	}
-	return string(buf), err
-}
diff --git a/pgtype/pgtype.go b/pgtype/pgtype.go
index 481c58be..ee2730ee 100644
--- a/pgtype/pgtype.go
+++ b/pgtype/pgtype.go
@@ -520,41 +520,6 @@ func (plan scanPlanDstTextDecoder) Scan(ci *ConnInfo, oid uint32, formatCode int
 	return newPlan.Scan(ci, oid, formatCode, src, dst)
 }
 
-type scanPlanDataTypeSQLScanner DataType
-
-func (plan *scanPlanDataTypeSQLScanner) Scan(ci *ConnInfo, oid uint32, formatCode int16, src []byte, dst interface{}) error {
-	scanner, ok := dst.(sql.Scanner)
-	if !ok {
-		newPlan := ci.PlanScan(oid, formatCode, dst)
-		return newPlan.Scan(ci, oid, formatCode, src, dst)
-	}
-
-	dt := (*DataType)(plan)
-	if dt.Codec != nil {
-		sqlValue, err := dt.Codec.DecodeDatabaseSQLValue(ci, oid, formatCode, src)
-		if err != nil {
-			return err
-		}
-		return scanner.Scan(sqlValue)
-	}
-	var err error
-	switch formatCode {
-	case BinaryFormatCode:
-		err = dt.binaryDecoder.DecodeBinary(ci, src)
-	case TextFormatCode:
-		err = dt.textDecoder.DecodeText(ci, src)
-	}
-	if err != nil {
-		return err
-	}
-
-	sqlSrc, err := DatabaseSQLValue(ci, dt.Value)
-	if err != nil {
-		return err
-	}
-	return scanner.Scan(sqlSrc)
-}
-
 type scanPlanDataTypeAssignTo DataType
 
 func (plan *scanPlanDataTypeAssignTo) Scan(ci *ConnInfo, oid uint32, formatCode int16, src []byte, dst interface{}) error {
@@ -596,6 +561,18 @@ func (plan *scanPlanDataTypeAssignTo) Scan(ci *ConnInfo, oid uint32, formatCode
 	return assignToErr
 }
 
+type scanPlanCodecSQLScanner struct{ c Codec }
+
+func (plan *scanPlanCodecSQLScanner) Scan(ci *ConnInfo, oid uint32, formatCode int16, src []byte, dst interface{}) error {
+	value, err := plan.c.DecodeDatabaseSQLValue(ci, oid, formatCode, src)
+	if err != nil {
+		return err
+	}
+
+	scanner := dst.(sql.Scanner)
+	return scanner.Scan(value)
+}
+
 type scanPlanSQLScanner struct{}
 
 func (scanPlanSQLScanner) Scan(ci *ConnInfo, oid uint32, formatCode int16, src []byte, dst interface{}) error {
@@ -1176,7 +1153,7 @@ func (ci *ConnInfo) PlanScan(oid uint32, formatCode int16, dst interface{}) Scan
 		for _, f := range tryWrappers {
 			if wrapperPlan, nextDst, ok := f(dst); ok {
 				if nextPlan := ci.PlanScan(oid, formatCode, nextDst); nextPlan != nil {
-					if _, ok := nextPlan.(*scanPlanDataTypeAssignTo); !ok { // avoid fallthrough -- this will go away when old system removed.
+					if _, ok := nextPlan.(scanPlanReflection); !ok { // avoid fallthrough -- this will go away when old system removed.
 						wrapperPlan.SetNext(nextPlan)
 						return wrapperPlan
 					}
@@ -1187,15 +1164,10 @@ func (ci *ConnInfo) PlanScan(oid uint32, formatCode int16, dst interface{}) Scan
 		if _, ok := dst.(*interface{}); ok {
 			return &pointerEmptyInterfaceScanPlan{codec: dt.Codec}
 		}
-	}
 
-	if dt != nil {
 		if _, ok := dst.(sql.Scanner); ok {
-			if _, found := ci.preferAssignToOverSQLScannerTypes[reflect.TypeOf(dst)]; !found {
-				return (*scanPlanDataTypeSQLScanner)(dt)
-			}
+			return &scanPlanCodecSQLScanner{c: dt.Codec}
 		}
-		return (*scanPlanDataTypeAssignTo)(dt)
 	}
 
 	if _, ok := dst.(sql.Scanner); ok {