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Copy pathquery.go
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494 lines (438 loc) · 11.8 KB
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package pgx
import (
"database/sql"
"errors"
"fmt"
"time"
)
// 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
mr *msgReader
fields []FieldDescription
vr ValueReader
rowCount int
columnIdx int
err error
startTime time.Time
sql string
args []interface{}
afterClose func(*Rows)
unlockConn bool
closed bool
}
func (rows *Rows) FieldDescriptions() []FieldDescription {
return rows.fields
}
func (rows *Rows) close() {
if rows.closed {
return
}
if rows.unlockConn {
rows.conn.unlock()
rows.unlockConn = false
}
rows.closed = true
if rows.err == nil {
if rows.conn.shouldLog(LogLevelInfo) {
endTime := time.Now()
rows.conn.log(LogLevelInfo, "Query", "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", "sql", rows.sql, "args", logQueryArgs(rows.args))
}
if rows.afterClose != nil {
rows.afterClose(rows)
}
}
func (rows *Rows) readUntilReadyForQuery() {
for {
t, r, err := rows.conn.rxMsg()
if err != nil {
rows.close()
return
}
switch t {
case readyForQuery:
rows.conn.rxReadyForQuery(r)
rows.close()
return
case rowDescription:
case dataRow:
case commandComplete:
case bindComplete:
case errorResponse:
err = rows.conn.rxErrorResponse(r)
if rows.err == nil {
rows.err = err
}
default:
err = rows.conn.processContextFreeMsg(t, r)
if err != nil {
rows.close()
return
}
}
}
}
// 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
}
rows.readUntilReadyForQuery()
rows.close()
}
func (rows *Rows) Err() error {
return rows.err
}
// abort signals that the query was not successfully sent to the server.
// This differs from Fatal in that it is not necessary to readUntilReadyForQuery
func (rows *Rows) abort(err error) {
if rows.err != nil {
return
}
rows.err = err
rows.close()
}
// 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
rows.vr = ValueReader{}
for {
t, r, err := rows.conn.rxMsg()
if err != nil {
rows.Fatal(err)
return false
}
switch t {
case readyForQuery:
rows.conn.rxReadyForQuery(r)
rows.close()
return false
case dataRow:
fieldCount := r.readInt16()
if int(fieldCount) != 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), fieldCount)))
return false
}
rows.mr = r
return true
case commandComplete:
case bindComplete:
default:
err = rows.conn.processContextFreeMsg(t, r)
if err != nil {
rows.Fatal(err)
return false
}
}
}
}
// Conn returns the *Conn this *Rows is using.
func (rows *Rows) Conn() *Conn {
return rows.conn
}
func (rows *Rows) nextColumn() (*ValueReader, bool) {
if rows.closed {
return nil, false
}
if len(rows.fields) <= rows.columnIdx {
rows.Fatal(ProtocolError("No next column available"))
return nil, false
}
if rows.vr.Len() > 0 {
rows.mr.readBytes(rows.vr.Len())
}
fd := &rows.fields[rows.columnIdx]
rows.columnIdx++
size := rows.mr.readInt32()
rows.vr = ValueReader{mr: rows.mr, fd: fd, valueBytesRemaining: size}
return &rows.vr, 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 = fmt.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 {
vr, _ := rows.nextColumn()
if d == nil {
continue
}
// Check for []byte first as we allow sidestepping the decoding process and retrieving the raw bytes
if b, ok := d.(*[]byte); ok {
// If it actually is a bytea then pass it through decodeBytea (so it can be decoded if it is in text format)
// Otherwise read the bytes directly regardless of what the actual type is.
if vr.Type().DataType == ByteaOid {
*b = decodeBytea(vr)
} else {
if vr.Len() != -1 {
*b = vr.ReadBytes(vr.Len())
} else {
*b = nil
}
}
} else if s, ok := d.(Scanner); ok {
err = s.Scan(vr)
if err != nil {
rows.Fatal(scanArgError{col: i, err: err})
}
} else if s, ok := d.(PgxScanner); ok {
err = s.ScanPgx(vr)
if err != nil {
rows.Fatal(scanArgError{col: i, err: err})
}
} else if s, ok := d.(sql.Scanner); ok {
var val interface{}
if 0 <= vr.Len() {
switch vr.Type().DataType {
case BoolOid:
val = decodeBool(vr)
case Int8Oid:
val = int64(decodeInt8(vr))
case Int2Oid:
val = int64(decodeInt2(vr))
case Int4Oid:
val = int64(decodeInt4(vr))
case TextOid, VarcharOid:
val = decodeText(vr)
case OidOid:
val = int64(decodeOid(vr))
case Float4Oid:
val = float64(decodeFloat4(vr))
case Float8Oid:
val = decodeFloat8(vr)
case DateOid:
val = decodeDate(vr)
case TimestampOid:
val = decodeTimestamp(vr)
case TimestampTzOid:
val = decodeTimestampTz(vr)
default:
val = vr.ReadBytes(vr.Len())
}
}
err = s.Scan(val)
if err != nil {
rows.Fatal(scanArgError{col: i, err: err})
}
} else if vr.Type().DataType == JsonOid {
// Because the argument passed to decodeJSON will escape the heap.
// This allows d to be stack allocated and only copied to the heap when
// we actually are decoding JSON. This saves one memory allocation per
// row.
d2 := d
decodeJSON(vr, &d2)
} else if vr.Type().DataType == JsonbOid {
// Same trick as above for getting stack allocation
d2 := d
decodeJSONB(vr, &d2)
} else {
if err := Decode(vr, d); err != nil {
rows.Fatal(scanArgError{col: i, err: err})
}
}
if vr.Err() != nil {
rows.Fatal(scanArgError{col: i, err: vr.Err()})
}
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 {
vr, _ := rows.nextColumn()
if vr.Len() == -1 {
values = append(values, nil)
continue
}
switch vr.Type().FormatCode {
// All intrinsic types (except string) are encoded with binary
// encoding so anything else should be treated as a string
case TextFormatCode:
values = append(values, vr.ReadString(vr.Len()))
case BinaryFormatCode:
switch vr.Type().DataType {
case TextOid, VarcharOid:
values = append(values, decodeText(vr))
case BoolOid:
values = append(values, decodeBool(vr))
case ByteaOid:
values = append(values, decodeBytea(vr))
case Int8Oid:
values = append(values, decodeInt8(vr))
case Int2Oid:
values = append(values, decodeInt2(vr))
case Int4Oid:
values = append(values, decodeInt4(vr))
case OidOid:
values = append(values, decodeOid(vr))
case Float4Oid:
values = append(values, decodeFloat4(vr))
case Float8Oid:
values = append(values, decodeFloat8(vr))
case BoolArrayOid:
values = append(values, decodeBoolArray(vr))
case Int2ArrayOid:
values = append(values, decodeInt2Array(vr))
case Int4ArrayOid:
values = append(values, decodeInt4Array(vr))
case Int8ArrayOid:
values = append(values, decodeInt8Array(vr))
case Float4ArrayOid:
values = append(values, decodeFloat4Array(vr))
case Float8ArrayOid:
values = append(values, decodeFloat8Array(vr))
case TextArrayOid, VarcharArrayOid:
values = append(values, decodeTextArray(vr))
case TimestampArrayOid, TimestampTzArrayOid:
values = append(values, decodeTimestampArray(vr))
case DateOid:
values = append(values, decodeDate(vr))
case TimestampTzOid:
values = append(values, decodeTimestampTz(vr))
case TimestampOid:
values = append(values, decodeTimestamp(vr))
case InetOid, CidrOid:
values = append(values, decodeInet(vr))
case JsonOid:
var d interface{}
decodeJSON(vr, &d)
values = append(values, d)
case JsonbOid:
var d interface{}
decodeJSONB(vr, &d)
values = append(values, d)
default:
rows.Fatal(errors.New("Values cannot handle binary format non-intrinsic types"))
}
default:
rows.Fatal(errors.New("Unknown format code"))
}
if vr.Err() != nil {
rows.Fatal(vr.Err())
}
if rows.Err() != nil {
return nil, rows.Err()
}
}
return values, rows.Err()
}
// AfterClose adds f to a LILO queue of functions that will be called when
// rows is closed.
func (rows *Rows) AfterClose(f func(*Rows)) {
if rows.afterClose == nil {
rows.afterClose = f
} else {
prevFn := rows.afterClose
rows.afterClose = func(rows *Rows) {
f(rows)
prevFn(rows)
}
}
}
// 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) {
c.lastActivityTime = time.Now()
rows := c.getRows(sql, args)
if err := c.lock(); err != nil {
rows.abort(err)
return rows, err
}
rows.unlockConn = true
ps, ok := c.preparedStatements[sql]
if !ok {
var err error
ps, err = c.Prepare("", sql)
if err != nil {
rows.abort(err)
return rows, rows.err
}
}
rows.sql = ps.SQL
rows.fields = ps.FieldDescriptions
err := c.sendPreparedQuery(ps, args...)
if err != nil {
rows.abort(err)
}
return rows, rows.err
}
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)
}