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// This file is part of ctap, a Rust implementation of the FIDO2 protocol.
// Copyright (c) Ariën Holthuizen <contact@ardaxi.com>
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// http://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 cbor_codec::{EncodeError, DecodeError};

use std::fmt;
use std::fmt::Display;
use failure::{Context, Backtrace, Fail};

pub type FidoResult<T> = Result<T, FidoError>;

#[derive(Debug)]
pub struct FidoError(Context<FidoErrorKind>);

#[derive(Copy, Clone, Eq, PartialEq, Debug, Fail)]
pub enum FidoErrorKind {
    #[fail(display = "Read/write error with device.")]
    Io,
    #[fail(display = "Error while reading packet from device.")]
    ReadPacket,
    #[fail(display = "Error while writing packet to device.")]
    WritePacket,
    #[fail(display = "Error while parsing CTAP from device.")]
    ParseCtap,
    #[fail(display = "Error while encoding CBOR for device.")]
    CborEncode,
    #[fail(display = "Error while decoding CBOR from device.")]
    CborDecode,
    #[fail(display = "Packets received from device in the wrong order.")]
    InvalidSequence,
    #[fail(display = "Failed to generate private keypair.")]
    GenerateKey,
    #[fail(display = "Failed to generate shared secret.")]
    GenerateSecret,
    #[fail(display = "Failed to parse public key.")]
    ParsePublic,
    #[fail(display = "Failed to encrypt PIN.")]
    EncryptPin,
    #[fail(display = "Failed to decrypt PIN.")]
    DecryptPin,
    #[fail(display = "Supplied key has incorrect type.")]
    KeyType,
    #[fail(display = "Device returned error: 0x{:x}", _0)]
    CborError(u8),
    #[fail(display = "Device does not support FIDO2")]
    DeviceUnsupported,
    #[fail(display = "This operating requires a PIN but none was provided.")]
    PinRequired,
}

impl Fail for FidoError {
    fn cause(&self) -> Option<&Fail> {
        self.0.cause()
    }

    fn backtrace(&self) -> Option<&Backtrace> {
        self.0.backtrace()
    }
}

impl Display for FidoError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        Display::fmt(&self.0, f)
    }
}

impl FidoError {
    pub fn kind(&self) -> FidoErrorKind {
        *self.0.get_context()
    }
}

impl From<FidoErrorKind> for FidoError {
    #[inline(always)]
    fn from(kind: FidoErrorKind) -> FidoError {
        FidoError(Context::new(kind))
    }
}

impl From<Context<FidoErrorKind>> for FidoError {
    fn from(inner: Context<FidoErrorKind>) -> FidoError {
        FidoError(inner)
    }
}

impl From<EncodeError> for FidoError {
    #[inline(always)]
    fn from(err: EncodeError) -> FidoError {
        FidoError(err.context(FidoErrorKind::CborEncode))
    }
}

impl From<DecodeError> for FidoError {
    #[inline(always)]
    fn from(err: DecodeError) -> FidoError {
        FidoError(err.context(FidoErrorKind::CborDecode))
    }
}