consul/vendor/github.com/SAP/go-hdb/internal/protocol/result.go

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2018-06-21 14:49:35 +00:00
/*
Copyright 2014 SAP SE
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 protocol
import (
"fmt"
"github.com/SAP/go-hdb/internal/bufio"
)
const (
resultsetIDSize = 8
)
type columnOptions int8
const (
coMandatory columnOptions = 0x01
coOptional columnOptions = 0x02
)
var columnOptionsText = map[columnOptions]string{
coMandatory: "mandatory",
coOptional: "optional",
}
func (k columnOptions) String() string {
t := make([]string, 0, len(columnOptionsText))
for option, text := range columnOptionsText {
if (k & option) != 0 {
t = append(t, text)
}
}
return fmt.Sprintf("%v", t)
}
//resultset id
type resultsetID struct {
id *uint64
}
func (id *resultsetID) kind() partKind {
return pkResultsetID
}
func (id *resultsetID) size() (int, error) {
return resultsetIDSize, nil
}
func (id *resultsetID) numArg() int {
return 1
}
func (id *resultsetID) setNumArg(int) {
//ignore - always 1
}
func (id *resultsetID) read(rd *bufio.Reader) error {
_id := rd.ReadUint64()
*id.id = _id
if trace {
outLogger.Printf("resultset id: %d", *id.id)
}
return rd.GetError()
}
func (id *resultsetID) write(wr *bufio.Writer) error {
wr.WriteUint64(*id.id)
if trace {
outLogger.Printf("resultset id: %d", *id.id)
}
return nil
}
// ResultFieldSet contains database field metadata for result fields.
type ResultFieldSet struct {
fields []*ResultField
names fieldNames
}
func newResultFieldSet(size int) *ResultFieldSet {
return &ResultFieldSet{
fields: make([]*ResultField, size),
names: newFieldNames(),
}
}
// String implements the Stringer interface.
func (f *ResultFieldSet) String() string {
a := make([]string, len(f.fields))
for i, f := range f.fields {
a[i] = f.String()
}
return fmt.Sprintf("%v", a)
}
func (f *ResultFieldSet) read(rd *bufio.Reader) {
for i := 0; i < len(f.fields); i++ {
field := newResultField(f.names)
field.read(rd)
f.fields[i] = field
}
pos := uint32(0)
for _, offset := range f.names.sortOffsets() {
if diff := int(offset - pos); diff > 0 {
rd.Skip(diff)
}
b, size := readShortUtf8(rd)
f.names.setName(offset, string(b))
pos += uint32(1 + size)
}
}
// NumField returns the number of fields of a query.
func (f *ResultFieldSet) NumField() int {
return len(f.fields)
}
// Field returns the field at index idx.
func (f *ResultFieldSet) Field(idx int) *ResultField {
return f.fields[idx]
}
const (
tableName = iota
schemaName
columnName
columnDisplayName
maxNames
)
// ResultField contains database field attributes for result fields.
type ResultField struct {
fieldNames fieldNames
columnOptions columnOptions
tc TypeCode
fraction int16
length int16
offsets [maxNames]uint32
}
func newResultField(fieldNames fieldNames) *ResultField {
return &ResultField{fieldNames: fieldNames}
}
// String implements the Stringer interface.
func (f *ResultField) String() string {
return fmt.Sprintf("columnsOptions %s typeCode %s fraction %d length %d tablename %s schemaname %s columnname %s columnDisplayname %s",
f.columnOptions,
f.tc,
f.fraction,
f.length,
f.fieldNames.name(f.offsets[tableName]),
f.fieldNames.name(f.offsets[schemaName]),
f.fieldNames.name(f.offsets[columnName]),
f.fieldNames.name(f.offsets[columnDisplayName]),
)
}
// TypeCode returns the type code of the field.
func (f *ResultField) TypeCode() TypeCode {
return f.tc
}
// TypeLength returns the type length of the field.
// see https://golang.org/pkg/database/sql/driver/#RowsColumnTypeLength
func (f *ResultField) TypeLength() (int64, bool) {
if f.tc.isVariableLength() {
return int64(f.length), true
}
return 0, false
}
// TypePrecisionScale returns the type precision and scale (decimal types) of the field.
// see https://golang.org/pkg/database/sql/driver/#RowsColumnTypePrecisionScale
func (f *ResultField) TypePrecisionScale() (int64, int64, bool) {
if f.tc.isDecimalType() {
return int64(f.length), int64(f.fraction), true
}
return 0, 0, false
}
// Nullable returns true if the field may be null, false otherwise.
// see https://golang.org/pkg/database/sql/driver/#RowsColumnTypeNullable
func (f *ResultField) Nullable() bool {
return f.columnOptions == coOptional
}
// Name returns the result field name.
func (f *ResultField) Name() string {
return f.fieldNames.name(f.offsets[columnDisplayName])
}
func (f *ResultField) read(rd *bufio.Reader) {
f.columnOptions = columnOptions(rd.ReadInt8())
f.tc = TypeCode(rd.ReadInt8())
f.fraction = rd.ReadInt16()
f.length = rd.ReadInt16()
rd.Skip(2) //filler
for i := 0; i < maxNames; i++ {
offset := rd.ReadUint32()
f.offsets[i] = offset
f.fieldNames.addOffset(offset)
}
}
//resultset metadata
type resultMetadata struct {
resultFieldSet *ResultFieldSet
numArg int
}
func (r *resultMetadata) String() string {
return fmt.Sprintf("result metadata: %s", r.resultFieldSet.fields)
}
func (r *resultMetadata) kind() partKind {
return pkResultMetadata
}
func (r *resultMetadata) setNumArg(numArg int) {
r.numArg = numArg
}
func (r *resultMetadata) read(rd *bufio.Reader) error {
r.resultFieldSet.read(rd)
if trace {
outLogger.Printf("read %s", r)
}
return rd.GetError()
}
//resultset
type resultset struct {
numArg int
s *Session
resultFieldSet *ResultFieldSet
fieldValues *FieldValues
}
func (r *resultset) String() string {
return fmt.Sprintf("resultset: %s", r.fieldValues)
}
func (r *resultset) kind() partKind {
return pkResultset
}
func (r *resultset) setNumArg(numArg int) {
r.numArg = numArg
}
func (r *resultset) read(rd *bufio.Reader) error {
cols := len(r.resultFieldSet.fields)
r.fieldValues.resize(r.numArg, cols)
for i := 0; i < r.numArg; i++ {
for j, field := range r.resultFieldSet.fields {
var err error
if r.fieldValues.values[i*cols+j], err = readField(r.s, rd, field.TypeCode()); err != nil {
return err
}
}
}
if trace {
outLogger.Printf("read %s", r)
}
return rd.GetError()
}