diff options
Diffstat (limited to 'vendor/github.com/jackc/pgx/v5/pgproto3/frontend.go')
| -rw-r--r-- | vendor/github.com/jackc/pgx/v5/pgproto3/frontend.go | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/vendor/github.com/jackc/pgx/v5/pgproto3/frontend.go b/vendor/github.com/jackc/pgx/v5/pgproto3/frontend.go new file mode 100644 index 0000000..b41abbe --- /dev/null +++ b/vendor/github.com/jackc/pgx/v5/pgproto3/frontend.go @@ -0,0 +1,454 @@ +package pgproto3 + +import ( + "bytes" + "encoding/binary" + "errors" + "fmt" + "io" +) + +// Frontend acts as a client for the PostgreSQL wire protocol version 3. +type Frontend struct { + cr *chunkReader + w io.Writer + + // tracer is used to trace messages when Send or Receive is called. This means an outbound message is traced + // before it is actually transmitted (i.e. before Flush). It is safe to change this variable when the Frontend is + // idle. Setting and unsetting tracer provides equivalent functionality to PQtrace and PQuntrace in libpq. + tracer *tracer + + wbuf []byte + encodeError error + + // Backend message flyweights + authenticationOk AuthenticationOk + authenticationCleartextPassword AuthenticationCleartextPassword + authenticationMD5Password AuthenticationMD5Password + authenticationGSS AuthenticationGSS + authenticationGSSContinue AuthenticationGSSContinue + authenticationSASL AuthenticationSASL + authenticationSASLContinue AuthenticationSASLContinue + authenticationSASLFinal AuthenticationSASLFinal + backendKeyData BackendKeyData + bindComplete BindComplete + closeComplete CloseComplete + commandComplete CommandComplete + copyBothResponse CopyBothResponse + copyData CopyData + copyInResponse CopyInResponse + copyOutResponse CopyOutResponse + copyDone CopyDone + dataRow DataRow + emptyQueryResponse EmptyQueryResponse + errorResponse ErrorResponse + functionCallResponse FunctionCallResponse + noData NoData + noticeResponse NoticeResponse + notificationResponse NotificationResponse + parameterDescription ParameterDescription + parameterStatus ParameterStatus + parseComplete ParseComplete + readyForQuery ReadyForQuery + rowDescription RowDescription + portalSuspended PortalSuspended + + bodyLen int + msgType byte + partialMsg bool + authType uint32 +} + +// NewFrontend creates a new Frontend. +func NewFrontend(r io.Reader, w io.Writer) *Frontend { + cr := newChunkReader(r, 0) + return &Frontend{cr: cr, w: w} +} + +// Send sends a message to the backend (i.e. the server). The message is buffered until Flush is called. Any error +// encountered will be returned from Flush. +// +// Send can work with any FrontendMessage. Some commonly used message types such as Bind have specialized send methods +// such as SendBind. These methods should be preferred when the type of message is known up front (e.g. when building an +// extended query protocol query) as they may be faster due to knowing the type of msg rather than it being hidden +// behind an interface. +func (f *Frontend) Send(msg FrontendMessage) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceMessage('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// Flush writes any pending messages to the backend (i.e. the server). +func (f *Frontend) Flush() error { + if err := f.encodeError; err != nil { + f.encodeError = nil + f.wbuf = f.wbuf[:0] + return &writeError{err: err, safeToRetry: true} + } + + if len(f.wbuf) == 0 { + return nil + } + + n, err := f.w.Write(f.wbuf) + + const maxLen = 1024 + if len(f.wbuf) > maxLen { + f.wbuf = make([]byte, 0, maxLen) + } else { + f.wbuf = f.wbuf[:0] + } + + if err != nil { + return &writeError{err: err, safeToRetry: n == 0} + } + + return nil +} + +// Trace starts tracing the message traffic to w. It writes in a similar format to that produced by the libpq function +// PQtrace. +func (f *Frontend) Trace(w io.Writer, options TracerOptions) { + f.tracer = &tracer{ + w: w, + buf: &bytes.Buffer{}, + TracerOptions: options, + } +} + +// Untrace stops tracing. +func (f *Frontend) Untrace() { + f.tracer = nil +} + +// SendBind sends a Bind message to the backend (i.e. the server). The message is buffered until Flush is called. Any +// error encountered will be returned from Flush. +func (f *Frontend) SendBind(msg *Bind) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceBind('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendParse sends a Parse message to the backend (i.e. the server). The message is buffered until Flush is called. Any +// error encountered will be returned from Flush. +func (f *Frontend) SendParse(msg *Parse) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceParse('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendClose sends a Close message to the backend (i.e. the server). The message is buffered until Flush is called. Any +// error encountered will be returned from Flush. +func (f *Frontend) SendClose(msg *Close) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceClose('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendDescribe sends a Describe message to the backend (i.e. the server). The message is buffered until Flush is +// called. Any error encountered will be returned from Flush. +func (f *Frontend) SendDescribe(msg *Describe) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceDescribe('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendExecute sends an Execute message to the backend (i.e. the server). The message is buffered until Flush is called. +// Any error encountered will be returned from Flush. +func (f *Frontend) SendExecute(msg *Execute) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.TraceQueryute('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendSync sends a Sync message to the backend (i.e. the server). The message is buffered until Flush is called. Any +// error encountered will be returned from Flush. +func (f *Frontend) SendSync(msg *Sync) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceSync('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendQuery sends a Query message to the backend (i.e. the server). The message is buffered until Flush is called. Any +// error encountered will be returned from Flush. +func (f *Frontend) SendQuery(msg *Query) { + if f.encodeError != nil { + return + } + + prevLen := len(f.wbuf) + newBuf, err := msg.Encode(f.wbuf) + if err != nil { + f.encodeError = err + return + } + f.wbuf = newBuf + + if f.tracer != nil { + f.tracer.traceQuery('F', int32(len(f.wbuf)-prevLen), msg) + } +} + +// SendUnbufferedEncodedCopyData immediately sends an encoded CopyData message to the backend (i.e. the server). This method +// is more efficient than sending a CopyData message with Send as the message data is not copied to the internal buffer +// before being written out. The internal buffer is flushed before the message is sent. +func (f *Frontend) SendUnbufferedEncodedCopyData(msg []byte) error { + err := f.Flush() + if err != nil { + return err + } + + n, err := f.w.Write(msg) + if err != nil { + return &writeError{err: err, safeToRetry: n == 0} + } + + if f.tracer != nil { + f.tracer.traceCopyData('F', int32(len(msg)-1), &CopyData{}) + } + + return nil +} + +func translateEOFtoErrUnexpectedEOF(err error) error { + if err == io.EOF { + return io.ErrUnexpectedEOF + } + return err +} + +// Receive receives a message from the backend. The returned message is only valid until the next call to Receive. +func (f *Frontend) Receive() (BackendMessage, error) { + if !f.partialMsg { + header, err := f.cr.Next(5) + if err != nil { + return nil, translateEOFtoErrUnexpectedEOF(err) + } + + f.msgType = header[0] + + msgLength := int(binary.BigEndian.Uint32(header[1:])) + if msgLength < 4 { + return nil, fmt.Errorf("invalid message length: %d", msgLength) + } + + f.bodyLen = msgLength - 4 + f.partialMsg = true + } + + msgBody, err := f.cr.Next(f.bodyLen) + if err != nil { + return nil, translateEOFtoErrUnexpectedEOF(err) + } + + f.partialMsg = false + + var msg BackendMessage + switch f.msgType { + case '1': + msg = &f.parseComplete + case '2': + msg = &f.bindComplete + case '3': + msg = &f.closeComplete + case 'A': + msg = &f.notificationResponse + case 'c': + msg = &f.copyDone + case 'C': + msg = &f.commandComplete + case 'd': + msg = &f.copyData + case 'D': + msg = &f.dataRow + case 'E': + msg = &f.errorResponse + case 'G': + msg = &f.copyInResponse + case 'H': + msg = &f.copyOutResponse + case 'I': + msg = &f.emptyQueryResponse + case 'K': + msg = &f.backendKeyData + case 'n': + msg = &f.noData + case 'N': + msg = &f.noticeResponse + case 'R': + var err error + msg, err = f.findAuthenticationMessageType(msgBody) + if err != nil { + return nil, err + } + case 's': + msg = &f.portalSuspended + case 'S': + msg = &f.parameterStatus + case 't': + msg = &f.parameterDescription + case 'T': + msg = &f.rowDescription + case 'V': + msg = &f.functionCallResponse + case 'W': + msg = &f.copyBothResponse + case 'Z': + msg = &f.readyForQuery + default: + return nil, fmt.Errorf("unknown message type: %c", f.msgType) + } + + err = msg.Decode(msgBody) + if err != nil { + return nil, err + } + + if f.tracer != nil { + f.tracer.traceMessage('B', int32(5+len(msgBody)), msg) + } + + return msg, nil +} + +// Authentication message type constants. +// See src/include/libpq/pqcomm.h for all +// constants. +const ( + AuthTypeOk = 0 + AuthTypeCleartextPassword = 3 + AuthTypeMD5Password = 5 + AuthTypeSCMCreds = 6 + AuthTypeGSS = 7 + AuthTypeGSSCont = 8 + AuthTypeSSPI = 9 + AuthTypeSASL = 10 + AuthTypeSASLContinue = 11 + AuthTypeSASLFinal = 12 +) + +func (f *Frontend) findAuthenticationMessageType(src []byte) (BackendMessage, error) { + if len(src) < 4 { + return nil, errors.New("authentication message too short") + } + f.authType = binary.BigEndian.Uint32(src[:4]) + + switch f.authType { + case AuthTypeOk: + return &f.authenticationOk, nil + case AuthTypeCleartextPassword: + return &f.authenticationCleartextPassword, nil + case AuthTypeMD5Password: + return &f.authenticationMD5Password, nil + case AuthTypeSCMCreds: + return nil, errors.New("AuthTypeSCMCreds is unimplemented") + case AuthTypeGSS: + return &f.authenticationGSS, nil + case AuthTypeGSSCont: + return &f.authenticationGSSContinue, nil + case AuthTypeSSPI: + return nil, errors.New("AuthTypeSSPI is unimplemented") + case AuthTypeSASL: + return &f.authenticationSASL, nil + case AuthTypeSASLContinue: + return &f.authenticationSASLContinue, nil + case AuthTypeSASLFinal: + return &f.authenticationSASLFinal, nil + default: + return nil, fmt.Errorf("unknown authentication type: %d", f.authType) + } +} + +// GetAuthType returns the authType used in the current state of the frontend. +// See SetAuthType for more information. +func (f *Frontend) GetAuthType() uint32 { + return f.authType +} + +func (f *Frontend) ReadBufferLen() int { + return f.cr.wp - f.cr.rp +} |