gtsocial-umbx

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function_call.go (3421B)

      1 package pgproto3
      2 
      3 import (
      4 	"encoding/binary"
      5 	"github.com/jackc/pgio"
      6 )
      7 
      8 type FunctionCall struct {
      9 	Function         uint32
     10 	ArgFormatCodes   []uint16
     11 	Arguments        [][]byte
     12 	ResultFormatCode uint16
     13 }
     14 
     15 // Frontend identifies this message as sendable by a PostgreSQL frontend.
     16 func (*FunctionCall) Frontend() {}
     17 
     18 // Decode decodes src into dst. src must contain the complete message with the exception of the initial 1 byte message
     19 // type identifier and 4 byte message length.
     20 func (dst *FunctionCall) Decode(src []byte) error {
     21 	*dst = FunctionCall{}
     22 	rp := 0
     23 	// Specifies the object ID of the function to call.
     24 	dst.Function = binary.BigEndian.Uint32(src[rp:])
     25 	rp += 4
     26 	// The number of argument format codes that follow (denoted C below).
     27 	// This can be zero to indicate that there are no arguments or that the arguments all use the default format (text);
     28 	// or one, in which case the specified format code is applied to all arguments;
     29 	// or it can equal the actual number of arguments.
     30 	nArgumentCodes := int(binary.BigEndian.Uint16(src[rp:]))
     31 	rp += 2
     32 	argumentCodes := make([]uint16, nArgumentCodes)
     33 	for i := 0; i < nArgumentCodes; i++ {
     34 		// The argument format codes. Each must presently be zero (text) or one (binary).
     35 		ac := binary.BigEndian.Uint16(src[rp:])
     36 		if ac != 0 && ac != 1 {
     37 			return &invalidMessageFormatErr{messageType: "FunctionCall"}
     38 		}
     39 		argumentCodes[i] = ac
     40 		rp += 2
     41 	}
     42 	dst.ArgFormatCodes = argumentCodes
     43 
     44 	// Specifies the number of arguments being supplied to the function.
     45 	nArguments := int(binary.BigEndian.Uint16(src[rp:]))
     46 	rp += 2
     47 	arguments := make([][]byte, nArguments)
     48 	for i := 0; i < nArguments; i++ {
     49 		// The length of the argument value, in bytes (this count does not include itself). Can be zero.
     50 		// As a special case, -1 indicates a NULL argument value. No value bytes follow in the NULL case.
     51 		argumentLength := int(binary.BigEndian.Uint32(src[rp:]))
     52 		rp += 4
     53 		if argumentLength == -1 {
     54 			arguments[i] = nil
     55 		} else {
     56 			// The value of the argument, in the format indicated by the associated format code. n is the above length.
     57 			argumentValue := src[rp : rp+argumentLength]
     58 			rp += argumentLength
     59 			arguments[i] = argumentValue
     60 		}
     61 	}
     62 	dst.Arguments = arguments
     63 	// The format code for the function result. Must presently be zero (text) or one (binary).
     64 	resultFormatCode := binary.BigEndian.Uint16(src[rp:])
     65 	if resultFormatCode != 0 && resultFormatCode != 1 {
     66 		return &invalidMessageFormatErr{messageType: "FunctionCall"}
     67 	}
     68 	dst.ResultFormatCode = resultFormatCode
     69 	return nil
     70 }
     71 
     72 // Encode encodes src into dst. dst will include the 1 byte message type identifier and the 4 byte message length.
     73 func (src *FunctionCall) Encode(dst []byte) []byte {
     74 	dst = append(dst, 'F')
     75 	sp := len(dst)
     76 	dst = pgio.AppendUint32(dst, 0) // Unknown length, set it at the end
     77 	dst = pgio.AppendUint32(dst, src.Function)
     78 	dst = pgio.AppendUint16(dst, uint16(len(src.ArgFormatCodes)))
     79 	for _, argFormatCode := range src.ArgFormatCodes {
     80 		dst = pgio.AppendUint16(dst, argFormatCode)
     81 	}
     82 	dst = pgio.AppendUint16(dst, uint16(len(src.Arguments)))
     83 	for _, argument := range src.Arguments {
     84 		if argument == nil {
     85 			dst = pgio.AppendInt32(dst, -1)
     86 		} else {
     87 			dst = pgio.AppendInt32(dst, int32(len(argument)))
     88 			dst = append(dst, argument...)
     89 		}
     90 	}
     91 	dst = pgio.AppendUint16(dst, src.ResultFormatCode)
     92 	pgio.SetInt32(dst[sp:], int32(len(dst[sp:])))
     93 	return dst
     94 }