huskies/crates/bft-json-crdt/src/json_crdt/mod.rs

//! JSON CRDT public interface: core traits, re-exports, and integration tests.
// TODO: serde's json object serialization and deserialization (correctly) do not define anything
// object field order in JSON objects. However, the hash check impl in bft-json-bft-crdt does take order
// into account. This is going to cause problems later for non-Rust implementations, BFT hash checking
// currently depends on JSON serialization/deserialization object order. This shouldn't be the case
// but I've hacked in an IndexMap for the moment to get the PoC working. To see the problem, replace this with
// a std HashMap, everything will screw up (annoyingly, only *most* of the time).

use crate::debug::debug_op_on_primitive;
use crate::keypair::AuthorId;
use crate::op::{Hashable, Op, PathSegment};

pub use bft_crdt_derive::*;

mod base;
mod signed_op;
mod value;

pub use base::BaseCrdt;
pub use signed_op::{OpState, SignedOp, CAUSAL_QUEUE_MAX};
pub use value::JsonValue;

/// Anything that can be nested in a JSON CRDT
pub trait CrdtNode: CrdtNodeFromValue + Hashable + Clone {
    /// Create a new CRDT of this type
    fn new(id: AuthorId, path: Vec<PathSegment>) -> Self;
    /// Apply an operation to this CRDT, forwarding if necessary
    fn apply(&mut self, op: Op<JsonValue>) -> OpState;
    /// Get a JSON representation of the value in this node
    fn view(&self) -> JsonValue;
}

/// The following types can be used as a 'terminal' type in CRDTs
pub trait MarkPrimitive: Into<JsonValue> + Default {}
impl MarkPrimitive for bool {}
impl MarkPrimitive for i32 {}
impl MarkPrimitive for i64 {}
impl MarkPrimitive for f64 {}
impl MarkPrimitive for char {}
impl MarkPrimitive for String {}
impl MarkPrimitive for JsonValue {}

/// Implement CrdtNode for non-CRDTs
/// This is a stub implementation so most functions don't do anything/log an error
impl<T> CrdtNode for T
where
    T: CrdtNodeFromValue + MarkPrimitive + Hashable + Clone,
{
    fn apply(&mut self, _op: Op<JsonValue>) -> OpState {
        OpState::ErrApplyOnPrimitive
    }

    fn view(&self) -> JsonValue {
        self.to_owned().into()
    }

    fn new(_id: AuthorId, _path: Vec<PathSegment>) -> Self {
        debug_op_on_primitive(_path);
        Default::default()
    }
}

/// Fallibly create a CRDT Node from a JSON Value
pub trait CrdtNodeFromValue: Sized {
    fn node_from(value: JsonValue, id: AuthorId, path: Vec<PathSegment>) -> Result<Self, String>;
}

/// Fallibly cast a JSON Value into a CRDT Node
pub trait IntoCrdtNode<T>: Sized {
    fn into_node(self, id: AuthorId, path: Vec<PathSegment>) -> Result<T, String>;
}

/// [`CrdtNodeFromValue`] implies [`IntoCrdtNode<T>`]
impl<T> IntoCrdtNode<T> for JsonValue
where
    T: CrdtNodeFromValue,
{
    fn into_node(self, id: AuthorId, path: Vec<PathSegment>) -> Result<T, String> {
        T::node_from(self, id, path)
    }
}

/// Trivial conversion from [`JsonValue`] to [`JsonValue`] as [`CrdtNodeFromValue`]
impl CrdtNodeFromValue for JsonValue {
    fn node_from(value: JsonValue, _id: AuthorId, _path: Vec<PathSegment>) -> Result<Self, String> {
        Ok(value)
    }
}

#[cfg(test)]
mod test {
    use serde_json::json;

    use crate::{
        json_crdt::{add_crdt_fields, BaseCrdt, CrdtNode, IntoCrdtNode, JsonValue, OpState},
        keypair::make_keypair,
        list_crdt::ListCrdt,
        lww_crdt::LwwRegisterCrdt,
        op::{print_path, ROOT_ID},
    };

    #[test]
    fn test_derive_basic() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Player {
            x: LwwRegisterCrdt<f64>,
            y: LwwRegisterCrdt<f64>,
        }

        let keypair = make_keypair();
        let crdt = BaseCrdt::<Player>::new(&keypair);
        assert_eq!(print_path(crdt.doc.x.path), "x");
        assert_eq!(print_path(crdt.doc.y.path), "y");
    }

    #[test]
    fn test_derive_nested() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Position {
            x: LwwRegisterCrdt<f64>,
            y: LwwRegisterCrdt<f64>,
        }

        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Player {
            pos: Position,
            balance: LwwRegisterCrdt<f64>,
            messages: ListCrdt<String>,
        }

        let keypair = make_keypair();
        let crdt = BaseCrdt::<Player>::new(&keypair);
        assert_eq!(print_path(crdt.doc.pos.x.path), "pos.x");
        assert_eq!(print_path(crdt.doc.pos.y.path), "pos.y");
        assert_eq!(print_path(crdt.doc.balance.path), "balance");
        assert_eq!(print_path(crdt.doc.messages.path), "messages");
    }

    #[test]
    fn test_lww_ops() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Test {
            a: LwwRegisterCrdt<f64>,
            b: LwwRegisterCrdt<bool>,
            c: LwwRegisterCrdt<String>,
        }

        let kp1 = make_keypair();
        let kp2 = make_keypair();
        let mut base1 = BaseCrdt::<Test>::new(&kp1);
        let mut base2 = BaseCrdt::<Test>::new(&kp2);

        let _1_a_1 = base1.doc.a.set(3.0).sign(&kp1);
        let _1_b_1 = base1.doc.b.set(true).sign(&kp1);
        let _2_a_1 = base2.doc.a.set(1.5).sign(&kp2);
        let _2_a_2 = base2.doc.a.set(2.13).sign(&kp2);
        let _2_c_1 = base2.doc.c.set("abc".to_string()).sign(&kp2);

        assert_eq!(base1.doc.a.view(), json!(3.0).into());
        assert_eq!(base2.doc.a.view(), json!(2.13).into());
        assert_eq!(base1.doc.b.view(), json!(true).into());
        assert_eq!(base2.doc.c.view(), json!("abc").into());

        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "a": 3.0,
                "b": true,
                "c": null,
            })
        );
        assert_eq!(
            base2.doc.view().into_json(),
            json!({
                "a": 2.13,
                "b": null,
                "c": "abc",
            })
        );

        assert_eq!(base2.apply(_1_a_1), OpState::Ok);
        assert_eq!(base2.apply(_1_b_1), OpState::Ok);
        assert_eq!(base1.apply(_2_a_1), OpState::Ok);
        assert_eq!(base1.apply(_2_a_2), OpState::Ok);
        assert_eq!(base1.apply(_2_c_1), OpState::Ok);

        assert_eq!(base1.doc.view().into_json(), base2.doc.view().into_json());
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "a": 2.13,
                "b": true,
                "c": "abc"
            })
        )
    }

    #[test]
    fn test_vec_and_map_ops() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Test {
            a: ListCrdt<String>,
        }

        let kp1 = make_keypair();
        let kp2 = make_keypair();
        let mut base1 = BaseCrdt::<Test>::new(&kp1);
        let mut base2 = BaseCrdt::<Test>::new(&kp2);

        let _1a = base1.doc.a.insert(ROOT_ID, "a".to_string()).sign(&kp1);
        let _1b = base1.doc.a.insert(_1a.id(), "b".to_string()).sign(&kp1);
        let _2c = base2.doc.a.insert(ROOT_ID, "c".to_string()).sign(&kp2);
        let _2d = base2.doc.a.insert(_1b.id(), "d".to_string()).sign(&kp2);

        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "a": ["a", "b"],
            })
        );

        // as _1b hasn't been delivered to base2 yet
        assert_eq!(
            base2.doc.view().into_json(),
            json!({
                "a": ["c"],
            })
        );

        assert_eq!(base2.apply(_1b), OpState::MissingCausalDependencies);
        assert_eq!(base2.apply(_1a), OpState::Ok);
        assert_eq!(base1.apply(_2d), OpState::Ok);
        assert_eq!(base1.apply(_2c), OpState::Ok);
        assert_eq!(base1.doc.view().into_json(), base2.doc.view().into_json());
    }

    #[test]
    fn test_causal_field_dependency() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Item {
            name: LwwRegisterCrdt<String>,
            soulbound: LwwRegisterCrdt<bool>,
        }

        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Player {
            inventory: ListCrdt<Item>,
            balance: LwwRegisterCrdt<f64>,
        }

        let kp1 = make_keypair();
        let kp2 = make_keypair();
        let mut base1 = BaseCrdt::<Player>::new(&kp1);
        let mut base2 = BaseCrdt::<Player>::new(&kp2);

        // require balance update to happen before inventory update
        let _add_money = base1.doc.balance.set(5000.0).sign(&kp1);
        let _spend_money = base1
            .doc
            .balance
            .set(3000.0)
            .sign_with_dependencies(&kp1, vec![&_add_money]);

        let sword: JsonValue = json!({
            "name": "Sword",
            "soulbound": true,
        })
        .into();
        let _new_inventory_item = base1
            .doc
            .inventory
            .insert_idx(0, sword)
            .sign_with_dependencies(&kp1, vec![&_spend_money]);

        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "balance": 3000.0,
                "inventory": [
                    {
                        "name": "Sword",
                        "soulbound": true
                    }
                ]
            })
        );

        // do it completely out of order
        assert_eq!(
            base2.apply(_new_inventory_item),
            OpState::MissingCausalDependencies
        );
        assert_eq!(
            base2.apply(_spend_money),
            OpState::MissingCausalDependencies
        );
        assert_eq!(base2.apply(_add_money), OpState::Ok);
        assert_eq!(base1.doc.view().into_json(), base2.doc.view().into_json());
    }

    #[test]
    fn test_2d_grid() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Game {
            grid: ListCrdt<ListCrdt<LwwRegisterCrdt<bool>>>,
        }

        let kp1 = make_keypair();
        let kp2 = make_keypair();
        let mut base1 = BaseCrdt::<Game>::new(&kp1);
        let mut base2 = BaseCrdt::<Game>::new(&kp2);

        // init a 2d grid
        let row0: JsonValue = json!([true, false]).into();
        let row1: JsonValue = json!([false, true]).into();
        let construct1 = base1.doc.grid.insert_idx(0, row0).sign(&kp1);
        let construct2 = base1.doc.grid.insert_idx(1, row1).sign(&kp1);

        assert_eq!(base2.apply(construct1), OpState::Ok);
        assert_eq!(base2.apply(construct2.clone()), OpState::Ok);

        assert_eq!(base1.doc.view().into_json(), base2.doc.view().into_json());
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "grid": [[true, false], [false, true]]
            })
        );

        let set1 = base1.doc.grid[0][0].set(false).sign(&kp1);
        let set2 = base2.doc.grid[1][1].set(false).sign(&kp2);
        assert_eq!(base1.apply(set2), OpState::Ok);
        assert_eq!(base2.apply(set1), OpState::Ok);

        assert_eq!(base1.doc.view().into_json(), base2.doc.view().into_json());
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "grid": [[false, false], [false, false]]
            })
        );

        let topright = base1.doc.grid[0].id_at(1).unwrap();
        base1.doc.grid[0].delete(topright);
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "grid": [[false], [false, false]]
            })
        );

        base1.doc.grid.delete(construct2.id());
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "grid": [[false]]
            })
        );
    }

    #[test]
    fn test_arb_json() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Test {
            reg: LwwRegisterCrdt<JsonValue>,
        }

        let kp1 = make_keypair();
        let mut base1 = BaseCrdt::<Test>::new(&kp1);

        let base_val: JsonValue = json!({
            "a": true,
            "b": "asdf",
            "c": {
                "d": [],
                "e": [ false ]
            }
        })
        .into();
        base1.doc.reg.set(base_val).sign(&kp1);
        assert_eq!(
            base1.doc.view().into_json(),
            json!({
                "reg": {
                    "a": true,
                    "b": "asdf",
                    "c": {
                        "d": [],
                        "e": [ false ]
                    }
                }
            })
        );
    }

    #[test]
    fn test_wrong_json_types() {
        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Nested {
            list: ListCrdt<f64>,
        }

        #[add_crdt_fields]
        #[derive(Clone, CrdtNode, Debug)]
        struct Test {
            reg: LwwRegisterCrdt<bool>,
            strct: ListCrdt<Nested>,
        }

        let key = make_keypair();
        let mut crdt = BaseCrdt::<Test>::new(&key);

        // wrong type should not go through
        crdt.doc.reg.set(32);
        assert_eq!(crdt.doc.reg.view(), json!(null).into());
        crdt.doc.reg.set(true);
        assert_eq!(crdt.doc.reg.view(), json!(true).into());

        // set nested
        let mut list_view: JsonValue = crdt.doc.strct.view().into();
        assert_eq!(list_view, json!([]).into());

        // only keeps actual numbers
        let list: JsonValue = json!({"list": [0, 123, -0.45, "char", []]}).into();
        crdt.doc.strct.insert_idx(0, list);
        list_view = crdt.doc.strct.view().into();
        assert_eq!(list_view, json!([{ "list": [0, 123, -0.45]}]).into());
    }
}