frameassembly 1.1.1

//! PostgreSQL v3.0 Wire Protocol Layer 7 database frontend/backend field parser.
//!
//! This module implements the `winnow` parser combinator for `POSTGRES` startup packets, simple
//! query messages, authentication responses, and backend status frames in FrameAssembly `.fasm`
//! specifications. It recognizes the `POSTGRES` protocol keyword, message type flags (`STARTUP`,
//! `QUERY`, `READY_FOR_QUERY`, `COMMAND_COMPLETE`, `ERROR_RESPONSE`, `AUTH_OK`), SQL query strings
//! (`SQL`), database role usernames (`USER`), and target database names (`DB`).

use winnow::ModalResult as PResult;
use winnow::combinator::{alt, cut_err};
use winnow::prelude::*;

use crate::ast::*;
use crate::lexer::Token;
use crate::parser::{parse_str_val, tag, ParsedField, Stream};

/// Parses a PostgreSQL protocol declaration or frontend/backend message field.
pub(crate) fn parse_postgres_field<'i, 'a>(
    input: &mut Stream<'i, 'a>,
) -> PResult<ParsedField<'a>> {
    alt((
        alt((
            tag(Token::Postgres)
                .map(|(_, s)| ParsedField::Protocol(Protocol::Postgres, (s.start, s.len()))),
            tag(Token::Startup).map(|(_, s)| ParsedField::L7Flag("STARTUP", (s.start, s.len()))),
            tag(Token::Query).map(|(_, s)| ParsedField::L7Flag("QUERY", (s.start, s.len()))),
            (tag(Token::Sql), cut_err(parse_str_val))
                .map(|((_, s), v)| ParsedField::L7StringField("SQL", v, (s.start, s.end - s.start))),
            tag(Token::ReadyForQuery)
                .map(|(_, s)| ParsedField::L7Flag("READY_FOR_QUERY", (s.start, s.len()))),
        )),
        alt((
            tag(Token::CommandComplete)
                .map(|(_, s)| ParsedField::L7Flag("COMMAND_COMPLETE", (s.start, s.len()))),
            tag(Token::ErrorResponse)
                .map(|(_, s)| ParsedField::L7Flag("ERROR_RESPONSE", (s.start, s.len()))),
            tag(Token::AuthOk).map(|(_, s)| ParsedField::L7Flag("AUTH_OK", (s.start, s.len()))),
            (tag(Token::User), parse_str_val)
                .map(|((_, s), v)| ParsedField::User(v, (s.start, s.end - s.start))),
            (tag(Token::Db), cut_err(parse_str_val))
                .map(|((_, s), v)| ParsedField::L7StringField("DB", v, (s.start, s.end - s.start))),
        )),
    ))
    .parse_next(input)
}