use de::read::SliceReader;

use {ErrorKind, Result};

/// A trait for erroring deserialization if not all bytes were read.

pub trait TrailingBytes {

    /// Checks a given slice reader to determine if deserialization used all bytes in the slice.

    fn check_end(reader: &SliceReader) -> Result<()>;

}

/// A TrailingBytes config that will allow trailing bytes in slices after deserialization.

#[derive(Copy, Clone)]

pub struct AllowTrailing;

/// A TrailingBytes config that will cause bincode to produce an error if bytes are left over in the slice when deserialization is complete.

#[derive(Copy, Clone)]

pub struct RejectTrailing;

impl TrailingBytes for AllowTrailing {

    #[inline(always)]

    fn check_end(_reader: &SliceReader) -> Result<()> {

        Ok(())

    }

}

impl TrailingBytes for RejectTrailing {

    #[inline(always)]

    fn check_end(reader: &SliceReader) -> Result<()> {

        if reader.is_finished() {

            Ok(())

        } else {

            Err(Box::new(ErrorKind::Custom(

                "Slice had bytes remaining after deserialization".to_string(),

            )))

        }

    }

}