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541 lines (458 loc) · 13.6 KB
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package pgx
import (
"context"
"database/sql"
"fmt"
"time"
"github.com/pkg/errors"
"github.com/jackc/pgx/internal/sanitize"
"github.com/jackc/pgx/pgproto3"
"github.com/jackc/pgx/pgtype"
)
// Row is a convenience wrapper over Rows that is returned by QueryRow.
type Row Rows
// Scan works the same as (*Rows Scan) with the following exceptions. If no
// rows were found it returns ErrNoRows. If multiple rows are returned it
// ignores all but the first.
func (r *Row) Scan(dest ...interface{}) (err error) {
rows := (*Rows)(r)
if rows.Err() != nil {
return rows.Err()
}
if !rows.Next() {
if rows.Err() == nil {
return ErrNoRows
}
return rows.Err()
}
rows.Scan(dest...)
rows.Close()
return rows.Err()
}
// Rows is the result set returned from *Conn.Query. Rows must be closed before
// the *Conn can be used again. Rows are closed by explicitly calling Close(),
// calling Next() until it returns false, or when a fatal error occurs.
type Rows struct {
conn *Conn
connPool *ConnPool
batch *Batch
values [][]byte
fields []FieldDescription
rowCount int
columnIdx int
err error
startTime time.Time
sql string
args []interface{}
unlockConn bool
closed bool
}
func (rows *Rows) FieldDescriptions() []FieldDescription {
return rows.fields
}
// Close closes the rows, making the connection ready for use again. It is safe
// to call Close after rows is already closed.
func (rows *Rows) Close() {
if rows.closed {
return
}
if rows.unlockConn {
rows.conn.unlock()
rows.unlockConn = false
}
rows.closed = true
rows.err = rows.conn.termContext(rows.err)
if rows.err == nil {
if rows.conn.shouldLog(LogLevelInfo) {
endTime := time.Now()
rows.conn.log(LogLevelInfo, "Query", map[string]interface{}{"sql": rows.sql, "args": logQueryArgs(rows.args), "time": endTime.Sub(rows.startTime), "rowCount": rows.rowCount})
}
} else if rows.conn.shouldLog(LogLevelError) {
rows.conn.log(LogLevelError, "Query", map[string]interface{}{"sql": rows.sql, "args": logQueryArgs(rows.args)})
}
if rows.batch != nil && rows.err != nil {
rows.batch.die(rows.err)
}
if rows.connPool != nil {
rows.connPool.Release(rows.conn)
}
}
func (rows *Rows) Err() error {
return rows.err
}
// fatal signals an error occurred after the query was sent to the server. It
// closes the rows automatically.
func (rows *Rows) fatal(err error) {
if rows.err != nil {
return
}
rows.err = err
rows.Close()
}
// Next prepares the next row for reading. It returns true if there is another
// row and false if no more rows are available. It automatically closes rows
// when all rows are read.
func (rows *Rows) Next() bool {
if rows.closed {
return false
}
rows.rowCount++
rows.columnIdx = 0
for {
msg, err := rows.conn.rxMsg()
if err != nil {
rows.fatal(err)
return false
}
switch msg := msg.(type) {
case *pgproto3.RowDescription:
rows.fields = rows.conn.rxRowDescription(msg)
for i := range rows.fields {
if dt, ok := rows.conn.ConnInfo.DataTypeForOID(rows.fields[i].DataType); ok {
rows.fields[i].DataTypeName = dt.Name
rows.fields[i].FormatCode = TextFormatCode
} else {
rows.fatal(errors.Errorf("unknown oid: %d", rows.fields[i].DataType))
return false
}
}
case *pgproto3.DataRow:
if len(msg.Values) != len(rows.fields) {
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))))
return false
}
rows.values = msg.Values
return true
case *pgproto3.CommandComplete:
rows.Close()
return false
default:
err = rows.conn.processContextFreeMsg(msg)
if err != nil {
rows.fatal(err)
return false
}
}
}
}
func (rows *Rows) nextColumn() ([]byte, *FieldDescription, bool) {
if rows.closed {
return nil, nil, false
}
if len(rows.fields) <= rows.columnIdx {
rows.fatal(ProtocolError("No next column available"))
return nil, nil, false
}
buf := rows.values[rows.columnIdx]
fd := &rows.fields[rows.columnIdx]
rows.columnIdx++
return buf, fd, true
}
type scanArgError struct {
col int
err error
}
func (e scanArgError) Error() string {
return fmt.Sprintf("can't scan into dest[%d]: %v", e.col, e.err)
}
// Scan reads the values from the current row into dest values positionally.
// dest can include pointers to core types, values implementing the Scanner
// interface, []byte, and nil. []byte will skip the decoding process and directly
// copy the raw bytes received from PostgreSQL. nil will skip the value entirely.
func (rows *Rows) Scan(dest ...interface{}) (err error) {
if len(rows.fields) != len(dest) {
err = errors.Errorf("Scan received wrong number of arguments, got %d but expected %d", len(dest), len(rows.fields))
rows.fatal(err)
return err
}
for i, d := range dest {
buf, fd, _ := rows.nextColumn()
if d == nil {
continue
}
if s, ok := d.(pgtype.BinaryDecoder); ok && fd.FormatCode == BinaryFormatCode {
err = s.DecodeBinary(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
} else if s, ok := d.(pgtype.TextDecoder); ok && fd.FormatCode == TextFormatCode {
err = s.DecodeText(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
} else {
if dt, ok := rows.conn.ConnInfo.DataTypeForOID(fd.DataType); ok {
value := dt.Value
switch fd.FormatCode {
case TextFormatCode:
if textDecoder, ok := value.(pgtype.TextDecoder); ok {
err = textDecoder.DecodeText(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
} else {
rows.fatal(scanArgError{col: i, err: errors.Errorf("%T is not a pgtype.TextDecoder", value)})
}
case BinaryFormatCode:
if binaryDecoder, ok := value.(pgtype.BinaryDecoder); ok {
err = binaryDecoder.DecodeBinary(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
} else {
rows.fatal(scanArgError{col: i, err: errors.Errorf("%T is not a pgtype.BinaryDecoder", value)})
}
default:
rows.fatal(scanArgError{col: i, err: errors.Errorf("unknown format code: %v", fd.FormatCode)})
}
if rows.Err() == nil {
if scanner, ok := d.(sql.Scanner); ok {
sqlSrc, err := pgtype.DatabaseSQLValue(rows.conn.ConnInfo, value)
if err != nil {
rows.fatal(err)
}
err = scanner.Scan(sqlSrc)
if err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
} else if err := value.AssignTo(d); err != nil {
rows.fatal(scanArgError{col: i, err: err})
}
}
} else {
rows.fatal(scanArgError{col: i, err: errors.Errorf("unknown oid: %v", fd.DataType)})
}
}
if rows.Err() != nil {
return rows.Err()
}
}
return nil
}
// Values returns an array of the row values
func (rows *Rows) Values() ([]interface{}, error) {
if rows.closed {
return nil, errors.New("rows is closed")
}
values := make([]interface{}, 0, len(rows.fields))
for range rows.fields {
buf, fd, _ := rows.nextColumn()
if buf == nil {
values = append(values, nil)
continue
}
if dt, ok := rows.conn.ConnInfo.DataTypeForOID(fd.DataType); ok {
value := dt.Value
switch fd.FormatCode {
case TextFormatCode:
decoder := value.(pgtype.TextDecoder)
if decoder == nil {
decoder = &pgtype.GenericText{}
}
err := decoder.DecodeText(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(err)
}
values = append(values, decoder.(pgtype.Value).Get())
case BinaryFormatCode:
decoder := value.(pgtype.BinaryDecoder)
if decoder == nil {
decoder = &pgtype.GenericBinary{}
}
err := decoder.DecodeBinary(rows.conn.ConnInfo, buf)
if err != nil {
rows.fatal(err)
}
values = append(values, value.Get())
default:
rows.fatal(errors.New("Unknown format code"))
}
} else {
rows.fatal(errors.New("Unknown type"))
}
if rows.Err() != nil {
return nil, rows.Err()
}
}
return values, rows.Err()
}
// Query executes sql with args. If there is an error the returned *Rows will
// be returned in an error state. So it is allowed to ignore the error returned
// from Query and handle it in *Rows.
func (c *Conn) Query(sql string, args ...interface{}) (*Rows, error) {
return c.QueryEx(context.Background(), sql, nil, args...)
}
func (c *Conn) getRows(sql string, args []interface{}) *Rows {
if len(c.preallocatedRows) == 0 {
c.preallocatedRows = make([]Rows, 64)
}
r := &c.preallocatedRows[len(c.preallocatedRows)-1]
c.preallocatedRows = c.preallocatedRows[0 : len(c.preallocatedRows)-1]
r.conn = c
r.startTime = c.lastActivityTime
r.sql = sql
r.args = args
return r
}
// QueryRow is a convenience wrapper over Query. Any error that occurs while
// querying is deferred until calling Scan on the returned *Row. That *Row will
// error with ErrNoRows if no rows are returned.
func (c *Conn) QueryRow(sql string, args ...interface{}) *Row {
rows, _ := c.Query(sql, args...)
return (*Row)(rows)
}
type QueryExOptions struct {
// When ParameterOIDs are present and the query is not a prepared statement,
// then ParameterOIDs and ResultFormatCodes will be used to avoid an extra
// network round-trip.
ParameterOIDs []pgtype.OID
ResultFormatCodes []int16
SimpleProtocol bool
}
func (c *Conn) QueryEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) (rows *Rows, err error) {
err = c.waitForPreviousCancelQuery(ctx)
if err != nil {
return nil, err
}
if err := c.ensureConnectionReadyForQuery(); err != nil {
return nil, err
}
c.lastActivityTime = time.Now()
rows = c.getRows(sql, args)
if err := c.lock(); err != nil {
rows.fatal(err)
return rows, err
}
rows.unlockConn = true
err = c.initContext(ctx)
if err != nil {
rows.fatal(err)
return rows, rows.err
}
if options != nil && options.SimpleProtocol {
err = c.sanitizeAndSendSimpleQuery(sql, args...)
if err != nil {
rows.fatal(err)
return rows, err
}
return rows, nil
}
if options != nil && len(options.ParameterOIDs) > 0 {
buf, err := c.buildOneRoundTripQueryEx(c.wbuf, sql, options, args)
if err != nil {
rows.fatal(err)
return rows, err
}
buf = appendSync(buf)
n, err := c.conn.Write(buf)
if err != nil && fatalWriteErr(n, err) {
rows.fatal(err)
c.die(err)
return nil, err
}
c.pendingReadyForQueryCount++
fieldDescriptions, err := c.readUntilRowDescription()
if err != nil {
rows.fatal(err)
return nil, err
}
if len(options.ResultFormatCodes) == 0 {
for i := range fieldDescriptions {
fieldDescriptions[i].FormatCode = TextFormatCode
}
} else if len(options.ResultFormatCodes) == 1 {
fc := options.ResultFormatCodes[0]
for i := range fieldDescriptions {
fieldDescriptions[i].FormatCode = fc
}
} else {
for i := range options.ResultFormatCodes {
fieldDescriptions[i].FormatCode = options.ResultFormatCodes[i]
}
}
rows.sql = sql
rows.fields = fieldDescriptions
return rows, nil
}
ps, ok := c.preparedStatements[sql]
if !ok {
var err error
ps, err = c.prepareEx("", sql, nil)
if err != nil {
rows.fatal(err)
return rows, rows.err
}
}
rows.sql = ps.SQL
rows.fields = ps.FieldDescriptions
err = c.sendPreparedQuery(ps, args...)
if err != nil {
rows.fatal(err)
}
return rows, rows.err
}
func (c *Conn) buildOneRoundTripQueryEx(buf []byte, sql string, options *QueryExOptions, arguments []interface{}) ([]byte, error) {
if len(arguments) != len(options.ParameterOIDs) {
return nil, errors.Errorf("mismatched number of arguments (%d) and options.ParameterOIDs (%d)", len(arguments), len(options.ParameterOIDs))
}
if len(options.ParameterOIDs) > 65535 {
return nil, errors.Errorf("Number of QueryExOptions ParameterOIDs must be between 0 and 65535, received %d", len(options.ParameterOIDs))
}
buf = appendParse(buf, "", sql, options.ParameterOIDs)
buf = appendDescribe(buf, 'S', "")
buf, err := appendBind(buf, "", "", c.ConnInfo, options.ParameterOIDs, arguments, options.ResultFormatCodes)
if err != nil {
return nil, err
}
buf = appendExecute(buf, "", 0)
return buf, nil
}
func (c *Conn) readUntilRowDescription() ([]FieldDescription, error) {
for {
msg, err := c.rxMsg()
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *pgproto3.ParameterDescription:
case *pgproto3.RowDescription:
fieldDescriptions := c.rxRowDescription(msg)
for i := range fieldDescriptions {
if dt, ok := c.ConnInfo.DataTypeForOID(fieldDescriptions[i].DataType); ok {
fieldDescriptions[i].DataTypeName = dt.Name
} else {
return nil, errors.Errorf("unknown oid: %d", fieldDescriptions[i].DataType)
}
}
return fieldDescriptions, nil
default:
if err := c.processContextFreeMsg(msg); err != nil {
return nil, err
}
}
}
}
func (c *Conn) sanitizeAndSendSimpleQuery(sql string, args ...interface{}) (err error) {
if c.RuntimeParams["standard_conforming_strings"] != "on" {
return errors.New("simple protocol queries must be run with standard_conforming_strings=on")
}
if c.RuntimeParams["client_encoding"] != "UTF8" {
return errors.New("simple protocol queries must be run with client_encoding=UTF8")
}
valueArgs := make([]interface{}, len(args))
for i, a := range args {
valueArgs[i], err = convertSimpleArgument(c.ConnInfo, a)
if err != nil {
return err
}
}
sql, err = sanitize.SanitizeSQL(sql, valueArgs...)
if err != nil {
return err
}
return c.sendSimpleQuery(sql)
}
func (c *Conn) QueryRowEx(ctx context.Context, sql string, options *QueryExOptions, args ...interface{}) *Row {
rows, _ := c.QueryEx(ctx, sql, options, args...)
return (*Row)(rows)
}