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package pgproto3
import (
"encoding/binary"
"github.com/jackc/pgx/v5/internal/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
}
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