// Smoldot

// Copyright (C) 2019-2022  Parity Technologies (UK) Ltd.

// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

// This program 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 General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with this program.  If not, see <http://www.gnu.org/licenses/>.

//! Serializing/deserializing a [`chain_information::ChainInformation`].

//!

//! This module contains the [`encode_chain_storage`] and [`decode_chain`] functions that can turn

//! a [`chain_information::ChainInformation`] into a string and back, with optionally the state of

//! the finalized block.

//! With no finalized block storage, the string is expected to be in the order of magnitude of a

//! few dozens kilobytes.

//!

//! The string format designed to be stable even if the structure of

//! [`chain_information::ChainInformation`] is later modified.

//!

//! This feature is expected to be used for example by light clients in order to easily (but

//! inefficiently) store the state of the finalized chain somewhere and later reload it.

use crate::chain::chain_information;

use alloc::{string::String, vec::Vec};

use core::iter;

use hashbrown::HashMap;

mod defs;

/// Serializes the given chain information as a JSON string.

///

/// This is a shortcut for [`encode_chain_storage`] with no `finalized_storage`.

pub fn encode_chain<'a>(

    information: impl Into<chain_information::ValidChainInformationRef<'a>>,

    block_number_bytes: usize,

) -> String {

    encode_chain_storage(

        information,

        block_number_bytes,

        None::<iter::Empty<(Vec<u8>, Vec<u8>)>>,

    )

}

Unexecuted instantiation: _RINvNtNtCsN16ciHI6Qf_7smoldot8database19finalized_serialize12encode_chainpEB6_

Unexecuted instantiation: _RINvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize12encode_chainRNtNtNtB6_5chain17chain_information21ValidChainInformationECsDDUKWWCHAU_18smoldot_light_wasm

Unexecuted instantiation: _RINvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize12encode_chainpEB6_

/// Serializes the given chain information and finalized block storage as a string.

pub fn encode_chain_storage<'a>(

    information: impl Into<chain_information::ValidChainInformationRef<'a>>,

    block_number_bytes: usize,

    finalized_storage: Option<impl Iterator<Item = (impl AsRef<[u8]>, impl AsRef<[u8]>)>>,

) -> String {

    let information = information.into();

    let decoded = defs::SerializedChainInformation::V1(defs::SerializedChainInformationV1::new(

        information.as_ref(),

        block_number_bytes,

        finalized_storage,

    ));

    serde_json::to_string(&decoded).unwrap()

}

Unexecuted instantiation: _RINvNtNtCsN16ciHI6Qf_7smoldot8database19finalized_serialize20encode_chain_storageppppEB6_

Unexecuted instantiation: _RINvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize20encode_chain_storageRNtNtNtB6_5chain17chain_information21ValidChainInformationINtNtCsdZExvAaxgia_5alloc3vec3VechEB2e_INtNtNtNtCsaYZPK01V26L_4core4iter7sources5empty5EmptyTB2e_B2e_EEECsDDUKWWCHAU_18smoldot_light_wasm

Unexecuted instantiation: _RINvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize20encode_chain_storageppppEB6_

/// Deserializes the information about the chain.

///

/// This is the invert operation of [`encode_chain_storage`].

pub fn decode_chain(encoded: &str, block_number_bytes: usize) -> Result<Decoded, CorruptedError> {

    let encoded: defs::SerializedChainInformation =

        serde_json::from_str(encoded).map_err(|e| CorruptedError(CorruptedErrorInner::Serde(e)))?;

Unexecuted instantiation: _RNCNvNtNtCsN16ciHI6Qf_7smoldot8database19finalized_serialize12decode_chain0B7_

Unexecuted instantiation: _RNCNvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize12decode_chain0B7_

    let defs::Decoded {

        chain_information,

        storage,

    } = encoded

        .decode(block_number_bytes)

        .map_err(|err| CorruptedError(CorruptedErrorInner::Deserialize(err)))?;

Unexecuted instantiation: _RNCNvNtNtCsN16ciHI6Qf_7smoldot8database19finalized_serialize12decode_chains_0B7_

Unexecuted instantiation: _RNCNvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize12decode_chains_0B7_

    let chain_information = chain_information::ValidChainInformation::try_from(chain_information)

        .map_err(CorruptedErrorInner::InvalidChain)

        .map_err(CorruptedError)?;

    Ok(Decoded {

        chain_information,

        storage,

    })

}

Unexecuted instantiation: _RNvNtNtCsN16ciHI6Qf_7smoldot8database19finalized_serialize12decode_chain

Unexecuted instantiation: _RNvNtNtCseuYC0Zibziv_7smoldot8database19finalized_serialize12decode_chain

/// Outcome of [`decode_chain`].

pub struct Decoded {

    /// Decoded chain information.

    pub chain_information: chain_information::ValidChainInformation,

    /// All the keys and values found in the database. `None` if no information was found.

    pub storage: Option<HashMap<Vec<u8>, Vec<u8>, fnv::FnvBuildHasher>>,

}

/// Opaque error indicating a corruption in the data stored in the local storage.

#[derive(Debug, derive_more::Display)]

Unexecuted instantiation: _RNvXs_NtNtCsN16ciHI6Qf_7smoldot8database19finalized_serializeNtB4_14CorruptedErrorNtNtCsaYZPK01V26L_4core3fmt7Display3fmt

Unexecuted instantiation: _RNvXs_NtNtCseuYC0Zibziv_7smoldot8database19finalized_serializeNtB4_14CorruptedErrorNtNtCsaYZPK01V26L_4core3fmt7Display3fmt

#[display(fmt = "{_0}")]

pub struct CorruptedError(CorruptedErrorInner);

#[derive(Debug, derive_more::Display)]

Unexecuted instantiation: _RNvXs1_NtNtCsN16ciHI6Qf_7smoldot8database19finalized_serializeNtB5_19CorruptedErrorInnerNtNtCsaYZPK01V26L_4core3fmt7Display3fmt

Unexecuted instantiation: _RNvXs1_NtNtCseuYC0Zibziv_7smoldot8database19finalized_serializeNtB5_19CorruptedErrorInnerNtNtCsaYZPK01V26L_4core3fmt7Display3fmt

enum CorruptedErrorInner {

    #[display(fmt = "{_0}")]

    Serde(serde_json::Error),

    #[display(fmt = "{_0}")]

    Deserialize(defs::DeserializeError),

    #[display(fmt = "Invalid chain information: {_0}")]

    InvalidChain(chain_information::ValidityError),

}