551 lines
14 KiB
Go
551 lines
14 KiB
Go
package pgx
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import (
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"context"
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"database/sql"
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"fmt"
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"reflect"
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"time"
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"github.com/pkg/errors"
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"github.com/jackc/pgx/internal/sanitize"
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"github.com/jackc/pgx/pgproto3"
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"github.com/jackc/pgx/pgtype"
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)
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// Row is a convenience wrapper over Rows that is returned by QueryRow.
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type Row Rows
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// Scan works the same as (*Rows Scan) with the following exceptions. If no
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// rows were found it returns ErrNoRows. If multiple rows are returned it
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// ignores all but the first.
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func (r *Row) Scan(dest ...interface{}) (err error) {
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rows := (*Rows)(r)
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if rows.Err() != nil {
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return rows.Err()
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}
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if !rows.Next() {
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if rows.Err() == nil {
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return ErrNoRows
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}
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return rows.Err()
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}
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rows.Scan(dest...)
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rows.Close()
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return rows.Err()
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}
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// Rows is the result set returned from *Conn.Query. Rows must be closed before
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// the *Conn can be used again. Rows are closed by explicitly calling Close(),
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// calling Next() until it returns false, or when a fatal error occurs.
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type Rows struct {
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conn *Conn
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connPool *ConnPool
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batch *Batch
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values [][]byte
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fields []FieldDescription
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rowCount int
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columnIdx int
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err error
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startTime time.Time
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sql string
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args []interface{}
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unlockConn bool
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closed bool
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}
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func (rows *Rows) FieldDescriptions() []FieldDescription {
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return rows.fields
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}
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// Close closes the rows, making the connection ready for use again. It is safe
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// to call Close after rows is already closed.
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func (rows *Rows) Close() {
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if rows.closed {
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return
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}
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if rows.unlockConn {
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rows.conn.unlock()
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rows.unlockConn = false
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}
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rows.closed = true
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rows.err = rows.conn.termContext(rows.err)
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if rows.err == nil {
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if rows.conn.shouldLog(LogLevelInfo) {
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endTime := time.Now()
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rows.conn.log(LogLevelInfo, "Query", map[string]interface{}{"sql": rows.sql, "args": logQueryArgs(rows.args), "time": endTime.Sub(rows.startTime), "rowCount": rows.rowCount})
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}
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} else if rows.conn.shouldLog(LogLevelError) {
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rows.conn.log(LogLevelError, "Query", map[string]interface{}{"sql": rows.sql, "args": logQueryArgs(rows.args)})
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}
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if rows.batch != nil && rows.err != nil {
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rows.batch.die(rows.err)
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}
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if rows.connPool != nil {
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rows.connPool.Release(rows.conn)
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}
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}
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func (rows *Rows) Err() error {
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return rows.err
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}
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// fatal signals an error occurred after the query was sent to the server. It
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// closes the rows automatically.
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func (rows *Rows) fatal(err error) {
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if rows.err != nil {
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return
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}
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rows.err = err
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rows.Close()
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}
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// Next prepares the next row for reading. It returns true if there is another
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// row and false if no more rows are available. It automatically closes rows
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// when all rows are read.
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func (rows *Rows) Next() bool {
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if rows.closed {
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return false
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}
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rows.rowCount++
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rows.columnIdx = 0
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for {
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msg, err := rows.conn.rxMsg()
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if err != nil {
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rows.fatal(err)
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return false
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}
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switch msg := msg.(type) {
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case *pgproto3.RowDescription:
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rows.fields = rows.conn.rxRowDescription(msg)
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for i := range rows.fields {
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if dt, ok := rows.conn.ConnInfo.DataTypeForOID(rows.fields[i].DataType); ok {
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rows.fields[i].DataTypeName = dt.Name
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rows.fields[i].FormatCode = TextFormatCode
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} else {
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rows.fatal(errors.Errorf("unknown oid: %d", rows.fields[i].DataType))
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return false
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}
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}
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case *pgproto3.DataRow:
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if len(msg.Values) != len(rows.fields) {
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rows.fatal(ProtocolError(fmt.Sprintf("Row description field count (%v) and data row field count (%v) do not match", len(rows.fields), len(msg.Values))))
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return false
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}
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rows.values = msg.Values
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return true
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case *pgproto3.CommandComplete:
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if rows.batch != nil {
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rows.batch.pendingCommandComplete = false
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}
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rows.Close()
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return false
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default:
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err = rows.conn.processContextFreeMsg(msg)
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if err != nil {
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rows.fatal(err)
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return false
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}
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}
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}
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}
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func (rows *Rows) nextColumn() ([]byte, *FieldDescription, bool) {
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if rows.closed {
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return nil, nil, false
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}
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if len(rows.fields) <= rows.columnIdx {
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rows.fatal(ProtocolError("No next column available"))
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return nil, nil, false
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}
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buf := rows.values[rows.columnIdx]
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fd := &rows.fields[rows.columnIdx]
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rows.columnIdx++
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return buf, fd, true
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}
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type scanArgError struct {
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col int
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err error
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}
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func (e scanArgError) Error() string {
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return fmt.Sprintf("can't scan into dest[%d]: %v", e.col, e.err)
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}
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// Scan reads the values from the current row into dest values positionally.
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// dest can include pointers to core types, values implementing the Scanner
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// interface, []byte, and nil. []byte will skip the decoding process and directly
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// copy the raw bytes received from PostgreSQL. nil will skip the value entirely.
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func (rows *Rows) Scan(dest ...interface{}) (err error) {
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if len(rows.fields) != len(dest) {
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err = errors.Errorf("Scan received wrong number of arguments, got %d but expected %d", len(dest), len(rows.fields))
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rows.fatal(err)
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return err
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}
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for i, d := range dest {
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buf, fd, _ := rows.nextColumn()
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if d == nil {
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continue
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}
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if s, ok := d.(pgtype.BinaryDecoder); ok && fd.FormatCode == BinaryFormatCode {
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err = s.DecodeBinary(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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} else if s, ok := d.(pgtype.TextDecoder); ok && fd.FormatCode == TextFormatCode {
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err = s.DecodeText(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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} else {
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if dt, ok := rows.conn.ConnInfo.DataTypeForOID(fd.DataType); ok {
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value := dt.Value
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switch fd.FormatCode {
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case TextFormatCode:
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if textDecoder, ok := value.(pgtype.TextDecoder); ok {
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err = textDecoder.DecodeText(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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} else {
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rows.fatal(scanArgError{col: i, err: errors.Errorf("%T is not a pgtype.TextDecoder", value)})
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}
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case BinaryFormatCode:
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if binaryDecoder, ok := value.(pgtype.BinaryDecoder); ok {
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err = binaryDecoder.DecodeBinary(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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} else {
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rows.fatal(scanArgError{col: i, err: errors.Errorf("%T is not a pgtype.BinaryDecoder", value)})
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}
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default:
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rows.fatal(scanArgError{col: i, err: errors.Errorf("unknown format code: %v", fd.FormatCode)})
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}
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if rows.Err() == nil {
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if scanner, ok := d.(sql.Scanner); ok {
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sqlSrc, err := pgtype.DatabaseSQLValue(rows.conn.ConnInfo, value)
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if err != nil {
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rows.fatal(err)
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}
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err = scanner.Scan(sqlSrc)
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if err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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} else if err := value.AssignTo(d); err != nil {
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rows.fatal(scanArgError{col: i, err: err})
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}
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}
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} else {
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rows.fatal(scanArgError{col: i, err: errors.Errorf("unknown oid: %v", fd.DataType)})
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}
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}
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if rows.Err() != nil {
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return rows.Err()
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}
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}
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return nil
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}
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// Values returns an array of the row values
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func (rows *Rows) Values() ([]interface{}, error) {
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if rows.closed {
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return nil, errors.New("rows is closed")
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}
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values := make([]interface{}, 0, len(rows.fields))
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for range rows.fields {
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buf, fd, _ := rows.nextColumn()
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if buf == nil {
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values = append(values, nil)
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continue
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}
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if dt, ok := rows.conn.ConnInfo.DataTypeForOID(fd.DataType); ok {
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value := reflect.New(reflect.ValueOf(dt.Value).Elem().Type()).Interface().(pgtype.Value)
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switch fd.FormatCode {
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case TextFormatCode:
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decoder := value.(pgtype.TextDecoder)
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if decoder == nil {
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decoder = &pgtype.GenericText{}
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}
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err := decoder.DecodeText(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(err)
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}
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values = append(values, decoder.(pgtype.Value).Get())
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case BinaryFormatCode:
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decoder := value.(pgtype.BinaryDecoder)
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if decoder == nil {
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decoder = &pgtype.GenericBinary{}
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}
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err := decoder.DecodeBinary(rows.conn.ConnInfo, buf)
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if err != nil {
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rows.fatal(err)
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}
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values = append(values, value.Get())
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default:
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rows.fatal(errors.New("Unknown format code"))
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}
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} else {
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rows.fatal(errors.New("Unknown type"))
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}
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if rows.Err() != nil {
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return nil, rows.Err()
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}
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}
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return values, rows.Err()
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}
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// Query executes sql with args. If there is an error the returned *Rows will
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// be returned in an error state. So it is allowed to ignore the error returned
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// from Query and handle it in *Rows.
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func (c *Conn) Query(sql string, args ...interface{}) (*Rows, error) {
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return c.QueryEx(context.Background(), sql, nil, args...)
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}
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func (c *Conn) getRows(sql string, args []interface{}) *Rows {
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if len(c.preallocatedRows) == 0 {
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c.preallocatedRows = make([]Rows, 64)
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}
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r := &c.preallocatedRows[len(c.preallocatedRows)-1]
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c.preallocatedRows = c.preallocatedRows[0 : len(c.preallocatedRows)-1]
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r.conn = c
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r.startTime = c.lastActivityTime
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r.sql = sql
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r.args = args
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return r
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}
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// QueryRow is a convenience wrapper over Query. Any error that occurs while
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// querying is deferred until calling Scan on the returned *Row. That *Row will
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// error with ErrNoRows if no rows are returned.
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func (c *Conn) QueryRow(sql string, args ...interface{}) *Row {
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rows, _ := c.Query(sql, args...)
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return (*Row)(rows)
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}
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type QueryExOptions struct {
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// When ParameterOIDs are present and the query is not a prepared statement,
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// then ParameterOIDs and ResultFormatCodes will be used to avoid an extra
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// network round-trip.
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ParameterOIDs []pgtype.OID
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ResultFormatCodes []int16
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SimpleProtocol bool
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}
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func (c *Conn) QueryEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) (rows *Rows, err error) {
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c.lastStmtSent = false
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c.lastActivityTime = time.Now()
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rows = c.getRows(sql, args)
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err = c.waitForPreviousCancelQuery(ctx)
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if err != nil {
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rows.fatal(err)
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return rows, err
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}
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if err := c.ensureConnectionReadyForQuery(); err != nil {
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rows.fatal(err)
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return rows, err
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}
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if err := c.lock(); err != nil {
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rows.fatal(err)
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return rows, err
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}
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rows.unlockConn = true
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err = c.initContext(ctx)
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if err != nil {
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rows.fatal(err)
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return rows, rows.err
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}
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if (options == nil && c.config.PreferSimpleProtocol) || (options != nil && options.SimpleProtocol) {
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c.lastStmtSent = true
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err = c.sanitizeAndSendSimpleQuery(sql, args...)
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if err != nil {
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rows.fatal(err)
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return rows, err
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}
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return rows, nil
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}
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if options != nil && len(options.ParameterOIDs) > 0 {
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buf, err := c.buildOneRoundTripQueryEx(c.wbuf, sql, options, args)
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if err != nil {
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rows.fatal(err)
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return rows, err
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}
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buf = appendSync(buf)
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c.lastStmtSent = true
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n, err := c.conn.Write(buf)
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if err != nil && fatalWriteErr(n, err) {
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rows.fatal(err)
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c.die(err)
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return rows, err
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}
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c.pendingReadyForQueryCount++
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fieldDescriptions, err := c.readUntilRowDescription()
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if err != nil {
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rows.fatal(err)
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return rows, err
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}
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if len(options.ResultFormatCodes) == 0 {
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for i := range fieldDescriptions {
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fieldDescriptions[i].FormatCode = TextFormatCode
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}
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} else if len(options.ResultFormatCodes) == 1 {
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fc := options.ResultFormatCodes[0]
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for i := range fieldDescriptions {
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fieldDescriptions[i].FormatCode = fc
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}
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} else {
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for i := range options.ResultFormatCodes {
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fieldDescriptions[i].FormatCode = options.ResultFormatCodes[i]
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}
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}
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rows.sql = sql
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rows.fields = fieldDescriptions
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return rows, nil
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}
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ps, ok := c.preparedStatements[sql]
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if !ok {
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var err error
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ps, err = c.prepareEx("", sql, nil)
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if err != nil {
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rows.fatal(err)
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return rows, rows.err
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}
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}
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rows.sql = ps.SQL
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rows.fields = ps.FieldDescriptions
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c.lastStmtSent = true
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err = c.sendPreparedQuery(ps, args...)
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if err != nil {
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rows.fatal(err)
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}
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return rows, rows.err
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}
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func (c *Conn) buildOneRoundTripQueryEx(buf []byte, sql string, options *QueryExOptions, arguments []interface{}) ([]byte, error) {
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if len(arguments) != len(options.ParameterOIDs) {
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return nil, errors.Errorf("mismatched number of arguments (%d) and options.ParameterOIDs (%d)", len(arguments), len(options.ParameterOIDs))
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}
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if len(options.ParameterOIDs) > 65535 {
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return nil, errors.Errorf("Number of QueryExOptions ParameterOIDs must be between 0 and 65535, received %d", len(options.ParameterOIDs))
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}
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buf = appendParse(buf, "", sql, options.ParameterOIDs)
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buf = appendDescribe(buf, 'S', "")
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buf, err := appendBind(buf, "", "", c.ConnInfo, options.ParameterOIDs, arguments, options.ResultFormatCodes)
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if err != nil {
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return nil, err
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}
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buf = appendExecute(buf, "", 0)
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return buf, nil
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}
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func (c *Conn) readUntilRowDescription() ([]FieldDescription, error) {
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for {
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msg, err := c.rxMsg()
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if err != nil {
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return nil, err
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}
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switch msg := msg.(type) {
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case *pgproto3.ParameterDescription:
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case *pgproto3.RowDescription:
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fieldDescriptions := c.rxRowDescription(msg)
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for i := range fieldDescriptions {
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if dt, ok := c.ConnInfo.DataTypeForOID(fieldDescriptions[i].DataType); ok {
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fieldDescriptions[i].DataTypeName = dt.Name
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} else {
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return nil, errors.Errorf("unknown oid: %d", fieldDescriptions[i].DataType)
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}
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}
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return fieldDescriptions, nil
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default:
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if err := c.processContextFreeMsg(msg); err != nil {
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return nil, err
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}
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}
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}
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}
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func (c *Conn) sanitizeAndSendSimpleQuery(sql string, args ...interface{}) (err error) {
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if c.RuntimeParams["standard_conforming_strings"] != "on" {
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return errors.New("simple protocol queries must be run with standard_conforming_strings=on")
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}
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if c.RuntimeParams["client_encoding"] != "UTF8" {
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return errors.New("simple protocol queries must be run with client_encoding=UTF8")
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}
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valueArgs := make([]interface{}, len(args))
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for i, a := range args {
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valueArgs[i], err = convertSimpleArgument(c.ConnInfo, a)
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if err != nil {
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return err
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}
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}
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sql, err = sanitize.SanitizeSQL(sql, valueArgs...)
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if err != nil {
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return err
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}
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return c.sendSimpleQuery(sql)
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}
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func (c *Conn) QueryRowEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) *Row {
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rows, _ := c.QueryEx(ctx, sql, options, args...)
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return (*Row)(rows)
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}
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