farcaster_core 0.6.4

// Copyright 2021-2022 Farcaster Devs
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA

use std::fmt;

use serde::de::{self, Unexpected, Visitor};

/// A visitor that deserializes a long string - a string containing at least
/// some minimum number of bytes.
pub(crate) struct HashString;

impl<'de> Visitor<'de> for HashString {
    type Value = String;

    fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        write!(
            formatter,
            "a string representing a hash in hex value prefixed with 0x"
        )
    }

    fn visit_str<E>(self, s: &str) -> Result<Self::Value, E>
    where
        E: de::Error,
    {
        if s.len() == 66 {
            Ok(s.to_string())
        } else {
            Err(de::Error::invalid_value(Unexpected::Str(s), &self))
        }
    }
}