package pq import ( "database/sql/driver" "encoding/binary" "errors" "fmt" "sync" ) var ( errCopyInClosed = errors.New("pq: copyin statement has already been closed") errBinaryCopyNotSupported = errors.New("pq: only text format supported for COPY") errCopyToNotSupported = errors.New("pq: COPY TO is not supported") errCopyNotSupportedOutsideTxn = errors.New("pq: COPY is only allowed inside a transaction") ) // CopyIn creates a COPY FROM statement which can be prepared with // Tx.Prepare(). The target table should be visible in search_path. func CopyIn(table string, columns ...string) string { stmt := "COPY " + QuoteIdentifier(table) + " (" for i, col := range columns { if i != 0 { stmt += ", " } stmt += QuoteIdentifier(col) } stmt += ") FROM STDIN" return stmt } // CopyInSchema creates a COPY FROM statement which can be prepared with // Tx.Prepare(). func CopyInSchema(schema, table string, columns ...string) string { stmt := "COPY " + QuoteIdentifier(schema) + "." + QuoteIdentifier(table) + " (" for i, col := range columns { if i != 0 { stmt += ", " } stmt += QuoteIdentifier(col) } stmt += ") FROM STDIN" return stmt } type copyin struct { cn *conn buffer []byte rowData chan []byte done chan bool closed bool sync.Mutex // guards err err error } const ciBufferSize = 64 * 1024 // flush buffer before the buffer is filled up and needs reallocation const ciBufferFlushSize = 63 * 1024 func (cn *conn) prepareCopyIn(q string) (_ driver.Stmt, err error) { if !cn.isInTransaction() { return nil, errCopyNotSupportedOutsideTxn } ci := ©in{ cn: cn, buffer: make([]byte, 0, ciBufferSize), rowData: make(chan []byte), done: make(chan bool, 1), } // add CopyData identifier + 4 bytes for message length ci.buffer = append(ci.buffer, 'd', 0, 0, 0, 0) b := cn.writeBuf('Q') b.string(q) cn.send(b) awaitCopyInResponse: for { t, r := cn.recv1() switch t { case 'G': if r.byte() != 0 { err = errBinaryCopyNotSupported break awaitCopyInResponse } go ci.resploop() return ci, nil case 'H': err = errCopyToNotSupported break awaitCopyInResponse case 'E': err = parseError(r) case 'Z': if err == nil { cn.bad = true errorf("unexpected ReadyForQuery in response to COPY") } cn.processReadyForQuery(r) return nil, err default: cn.bad = true errorf("unknown response for copy query: %q", t) } } // something went wrong, abort COPY before we return b = cn.writeBuf('f') b.string(err.Error()) cn.send(b) for { t, r := cn.recv1() switch t { case 'c', 'C', 'E': case 'Z': // correctly aborted, we're done cn.processReadyForQuery(r) return nil, err default: cn.bad = true errorf("unknown response for CopyFail: %q", t) } } } func (ci *copyin) flush(buf []byte) { // set message length (without message identifier) binary.BigEndian.PutUint32(buf[1:], uint32(len(buf)-1)) _, err := ci.cn.c.Write(buf) if err != nil { panic(err) } } func (ci *copyin) resploop() { for { var r readBuf t, err := ci.cn.recvMessage(&r) if err != nil { ci.cn.bad = true ci.setError(err) ci.done <- true return } switch t { case 'C': // complete case 'N': // NoticeResponse case 'Z': ci.cn.processReadyForQuery(&r) ci.done <- true return case 'E': err := parseError(&r) ci.setError(err) default: ci.cn.bad = true ci.setError(fmt.Errorf("unknown response during CopyIn: %q", t)) ci.done <- true return } } } func (ci *copyin) isErrorSet() bool { ci.Lock() isSet := (ci.err != nil) ci.Unlock() return isSet } // setError() sets ci.err if one has not been set already. Caller must not be // holding ci.Mutex. func (ci *copyin) setError(err error) { ci.Lock() if ci.err == nil { ci.err = err } ci.Unlock() } func (ci *copyin) NumInput() int { return -1 } func (ci *copyin) Query(v []driver.Value) (r driver.Rows, err error) { return nil, ErrNotSupported } // Exec inserts values into the COPY stream. The insert is asynchronous // and Exec can return errors from previous Exec calls to the same // COPY stmt. // // You need to call Exec(nil) to sync the COPY stream and to get any // errors from pending data, since Stmt.Close() doesn't return errors // to the user. func (ci *copyin) Exec(v []driver.Value) (r driver.Result, err error) { if ci.closed { return nil, errCopyInClosed } if ci.cn.bad { return nil, driver.ErrBadConn } defer ci.cn.errRecover(&err) if ci.isErrorSet() { return nil, ci.err } if len(v) == 0 { err = ci.Close() ci.closed = true return nil, err } numValues := len(v) for i, value := range v { ci.buffer = appendEncodedText(&ci.cn.parameterStatus, ci.buffer, value) if i < numValues-1 { ci.buffer = append(ci.buffer, '\t') } } ci.buffer = append(ci.buffer, '\n') if len(ci.buffer) > ciBufferFlushSize { ci.flush(ci.buffer) // reset buffer, keep bytes for message identifier and length ci.buffer = ci.buffer[:5] } return driver.RowsAffected(0), nil } func (ci *copyin) Close() (err error) { if ci.closed { return errCopyInClosed } if ci.cn.bad { return driver.ErrBadConn } defer ci.cn.errRecover(&err) if len(ci.buffer) > 0 { ci.flush(ci.buffer) } // Avoid touching the scratch buffer as resploop could be using it. err = ci.cn.sendSimpleMessage('c') if err != nil { return err } <-ci.done if ci.isErrorSet() { err = ci.err return err } return nil }