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// Copyright 2018 Serde Developers
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

use serde::{de, ser};
use std::fmt::{self, Display};

pub type Result<T> = std::result::Result<T, Error>;

// This is a bare-bones implementation. A real library would provide additional
// information in its error type, for example the line and column at which the
// error occurred, the byte offset into the input, or the current key being
// processed.
#[derive(Clone, Debug, PartialEq)]
pub enum Error {
    // One or more variants that can be created by data structures through the
    // `ser::Error` and `de::Error` traits. For example the Serialize impl for
    // Mutex<T> might return an error because the mutex is poisoned, or the
    // Deserialize impl for a struct may return an error because a required
    // field is missing.
    Message(String),

    // Zero or more variants that can be created directly by the Serializer and
    // Deserializer without going through `ser::Error` and `de::Error`. These
    // are specific to the format, in this case JSON.
    Eof,
    Syntax,
    ExpectedBoolean,
    ExpectedInteger,
    ExpectedString,
    ExpectedNull,
    ExpectedArray,
    ExpectedArrayComma,
    ExpectedArrayEnd,
    ExpectedMap,
    ExpectedMapColon,
    ExpectedMapComma,
    ExpectedMapEnd,
    ExpectedEnum,
    TrailingCharacters,
}

impl ser::Error for Error {
    fn custom<T: Display>(msg: T) -> Self {
        Error::Message(msg.to_string())
    }
}

impl de::Error for Error {
    fn custom<T: Display>(msg: T) -> Self {
        Error::Message(msg.to_string())
    }
}

impl Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Error::Message(msg) => write!(f, "{}", msg),
            Error::Eof => f.write_str("unexpected end of input"),
            /* and so forth */
            _ => unimplemented!(),
        }
    }
}

impl std::error::Error for Error {}