package pgproto3 import ( "encoding/binary" "github.com/jackc/pgio" ) type FunctionCall struct { Function uint32 ArgFormatCodes []uint16 Arguments [][]byte ResultFormatCode uint16 } // Frontend identifies this message as sendable by a PostgreSQL frontend. func (*FunctionCall) Frontend() {} // Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message // type identifier and 4 byte message length. func (dst *FunctionCall) Decode(src []byte) error { *dst = FunctionCall{} rp := 0 // Specifies the object ID of the function to call. dst.Function = binary.BigEndian.Uint32(src[rp:]) rp += 4 // The number of argument format codes that follow (denoted C below). // This can be zero to indicate that there are no arguments or that the arguments all use the default format (text); // or one, in which case the specified format code is applied to all arguments; // or it can equal the actual number of arguments. nArgumentCodes := int(binary.BigEndian.Uint16(src[rp:])) rp += 2 argumentCodes := make([]uint16, nArgumentCodes) for i := 0; i < nArgumentCodes; i++ { // The argument format codes. Each must presently be zero (text) or one (binary). ac := binary.BigEndian.Uint16(src[rp:]) if ac != 0 && ac != 1 { return &invalidMessageFormatErr{messageType: "FunctionCall"} } argumentCodes[i] = ac rp += 2 } dst.ArgFormatCodes = argumentCodes // Specifies the number of arguments being supplied to the function. nArguments := int(binary.BigEndian.Uint16(src[rp:])) rp += 2 arguments := make([][]byte, nArguments) for i := 0; i < nArguments; i++ { // The length of the argument value, in bytes (this count does not include itself). Can be zero. // As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case. argumentLength := int(binary.BigEndian.Uint32(src[rp:])) rp += 4 if argumentLength == -1 { arguments[i] = nil } else { // The value of the argument, in the format indicated by the associated format code. n is the above length. argumentValue := src[rp : rp+argumentLength] rp += argumentLength arguments[i] = argumentValue } } dst.Arguments = arguments // The format code for the function result. Must presently be zero (text) or one (binary). resultFormatCode := binary.BigEndian.Uint16(src[rp:]) if resultFormatCode != 0 && resultFormatCode != 1 { return &invalidMessageFormatErr{messageType: "FunctionCall"} } dst.ResultFormatCode = resultFormatCode return nil } // Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length. func (src *FunctionCall) Encode(dst []byte) []byte { dst = append(dst, 'F') sp := len(dst) dst = pgio.AppendUint32(dst, 0) // Unknown length, set it at the end dst = pgio.AppendUint32(dst, src.Function) dst = pgio.AppendUint16(dst, uint16(len(src.ArgFormatCodes))) for _, argFormatCode := range src.ArgFormatCodes { dst = pgio.AppendUint16(dst, argFormatCode) } dst = pgio.AppendUint16(dst, uint16(len(src.Arguments))) for _, argument := range src.Arguments { if argument == nil { dst = pgio.AppendInt32(dst, -1) } else { dst = pgio.AppendInt32(dst, int32(len(argument))) dst = append(dst, argument...) } } dst = pgio.AppendUint16(dst, src.ResultFormatCode) pgio.SetInt32(dst[sp:], int32(len(dst[sp:]))) return dst }