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