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// use core::ops::Try;

use crate::{
    codec_err::DecodeError, DecodeErrorHandler, DefaultErrorHandler, NestedDecodeInput, TypeInfo,
};

/// Trait that allows zero-copy read of value-references from slices in LE format.
pub trait NestedDecode: Sized {
    // !INTERNAL USE ONLY!
    // This const helps dharitri-wasm to optimize the encoding/decoding by doing fake specialization.
    #[doc(hidden)]
    const TYPE_INFO: TypeInfo = TypeInfo::Unknown;

    /// Attempt to deserialise the value from input,
    /// using the format of an object nested inside another structure.
    /// In case of success returns the deserialized value and the number of bytes consumed during the operation.
    fn dep_decode<I: NestedDecodeInput>(input: &mut I) -> Result<Self, DecodeError> {
        Self::dep_decode_or_handle_err(input, DefaultErrorHandler)
    }

    /// Version of `dep_decode` that can handle errors as soon as they occur.
    /// For instance in can exit immediately and make sure that if it returns, it is a success.
    /// By not deferring error handling, this can lead to somewhat smaller bytecode.
    fn dep_decode_or_handle_err<I, H>(input: &mut I, h: H) -> Result<Self, H::HandledErr>
    where
        I: NestedDecodeInput,
        H: DecodeErrorHandler,
    {
        match Self::dep_decode(input) {
            Ok(v) => Ok(v),
            Err(e) => Err(h.handle_error(e)),
        }
    }
}