Added contract query to check if given address owns a mixnode/gateway (#544)

* Added contract query to check if given address owns a mixnode/gateway

* Fixed merge conflict

common/mixnet-contract/src/gateway.rs

@@ -109,3 +109,9 @@ impl PagedGatewayResponse {
         }
     }
 }
+
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
+pub struct GatewayOwnershipResponse {
+    pub address: HumanAddr,
+    pub has_gateway: bool,
+}

common/mixnet-contract/src/lib.rs

@@ -2,5 +2,5 @@ mod gateway;
 mod mixnode;
 
 pub use cosmwasm_std::{Coin, HumanAddr};
-pub use gateway::{Gateway, GatewayBond, PagedGatewayResponse};
-pub use mixnode::{MixNode, MixNodeBond, PagedResponse};
+pub use gateway::{Gateway, GatewayBond, GatewayOwnershipResponse, PagedGatewayResponse};
+pub use mixnode::{MixNode, MixNodeBond, MixOwnershipResponse, PagedResponse};

common/mixnet-contract/src/mixnode.rs

@@ -105,3 +105,9 @@ impl PagedResponse {
         }
     }
 }
+
+#[derive(Clone, Debug, Deserialize, PartialEq, Serialize, JsonSchema)]
+pub struct MixOwnershipResponse {
+    pub address: HumanAddr,
+    pub has_node: bool,
+}

contracts/mixnet/src/contract.rs

@@ -1,5 +1,7 @@
 use crate::msg::{HandleMsg, InitMsg, QueryMsg};
-use crate::queries::{query_gateways_paged, query_mixnodes_paged};
+use crate::queries::{
+    query_gateways_paged, query_mixnodes_paged, query_owns_gateway, query_owns_mixnode,
+};
 use crate::state::{config, gateways, gateways_read, State};
 use crate::{error::ContractError, state::mixnodes, state::mixnodes_read};
 use cosmwasm_std::{
@@ -200,6 +202,8 @@ pub fn query(deps: Deps, _env: Env, msg: QueryMsg) -> StdResult<Binary> {
         QueryMsg::GetGateways { limit, start_after } => {
             to_binary(&query_gateways_paged(deps, start_after, limit)?)
         }
+        QueryMsg::OwnsMixnode { address } => to_binary(&query_owns_mixnode(deps, address)?),
+        QueryMsg::OwnsGateway { address } => to_binary(&query_owns_gateway(deps, address)?),
     }
 }
 

contracts/mixnet/src/msg.rs

@@ -26,4 +26,10 @@ pub enum QueryMsg {
         start_after: Option<HumanAddr>,
         limit: Option<u32>,
     },
+    OwnsMixnode {
+        address: HumanAddr,
+    },
+    OwnsGateway {
+        address: HumanAddr,
+    },
 }

contracts/mixnet/src/queries.rs

@@ -1,11 +1,14 @@
 // settings for pagination
-use crate::state::{gateways_read, PREFIX_MIXNODES};
+use crate::state::{gateways_read, mixnodes_read, PREFIX_MIXNODES};
 use cosmwasm_std::Deps;
 use cosmwasm_std::HumanAddr;
 use cosmwasm_std::Order;
 use cosmwasm_std::StdResult;
 use cosmwasm_storage::bucket_read;
-use mixnet_contract::{GatewayBond, MixNodeBond, PagedGatewayResponse, PagedResponse};
+use mixnet_contract::{
+    GatewayBond, GatewayOwnershipResponse, MixNodeBond, MixOwnershipResponse, PagedGatewayResponse,
+    PagedResponse,
+};
 
 const MAX_LIMIT: u32 = 30;
 const DEFAULT_LIMIT: u32 = 10;
@@ -52,6 +55,29 @@ pub(crate) fn query_gateways_paged(
     Ok(PagedGatewayResponse::new(nodes, limit, start_next_after))
 }
 
+pub(crate) fn query_owns_mixnode(
+    deps: Deps,
+    address: HumanAddr,
+) -> StdResult<MixOwnershipResponse> {
+    let has_node = mixnodes_read(deps.storage)
+        .may_load(address.as_ref())?
+        .is_some();
+    Ok(MixOwnershipResponse { address, has_node })
+}
+
+pub(crate) fn query_owns_gateway(
+    deps: Deps,
+    address: HumanAddr,
+) -> StdResult<GatewayOwnershipResponse> {
+    let has_gateway = gateways_read(deps.storage)
+        .may_load(address.as_ref())?
+        .is_some();
+    Ok(GatewayOwnershipResponse {
+        address,
+        has_gateway,
+    })
+}
+
 /// Adds a 0 byte to terminate the `start_after` value given. This allows CosmWasm
 /// to get the succeeding key as the start of the next page.
 fn calculate_start_value(
@@ -306,4 +332,68 @@ mod tests {
         // now we have 2 pages, with 2 results on the second page
         assert_eq!(2, page2.nodes.len());
     }
+
+    #[test]
+    fn query_for_mixnode_owner_works() {
+        let mut deps = helpers::init_contract();
+
+        // "fred" does not own a mixnode if there are no mixnodes
+        let res = query_owns_mixnode(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_node);
+
+        // mixnode was added to "bob", "fred" still does not own one
+        let node = helpers::mixnode_bond_fixture();
+        mixnodes(&mut deps.storage)
+            .save("bob".as_bytes(), &node)
+            .unwrap();
+
+        let res = query_owns_mixnode(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_node);
+
+        // "fred" now owns a mixnode!
+        let node2 = helpers::mixnode_bond_fixture();
+        mixnodes(&mut deps.storage)
+            .save("fred".as_bytes(), &node2)
+            .unwrap();
+
+        let res = query_owns_mixnode(deps.as_ref(), "fred".into()).unwrap();
+        assert!(res.has_node);
+
+        // but after unbonding it, he doesn't own one anymore
+        mixnodes(&mut deps.storage).remove("fred".as_bytes());
+        let res = query_owns_mixnode(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_node);
+    }
+
+    #[test]
+    fn query_for_gateway_owner_works() {
+        let mut deps = helpers::init_contract();
+
+        // "fred" does not own a mixnode if there are no mixnodes
+        let res = query_owns_gateway(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_gateway);
+
+        // mixnode was added to "bob", "fred" still does not own one
+        let node = helpers::gateway_bond_fixture();
+        gateways(&mut deps.storage)
+            .save("bob".as_bytes(), &node)
+            .unwrap();
+
+        let res = query_owns_gateway(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_gateway);
+
+        // "fred" now owns a mixnode!
+        let node2 = helpers::gateway_bond_fixture();
+        gateways(&mut deps.storage)
+            .save("fred".as_bytes(), &node2)
+            .unwrap();
+
+        let res = query_owns_gateway(deps.as_ref(), "fred".into()).unwrap();
+        assert!(res.has_gateway);
+
+        // but after unbonding it, he doesn't own one anymore
+        gateways(&mut deps.storage).remove("fred".as_bytes());
+        let res = query_owns_gateway(deps.as_ref(), "fred".into()).unwrap();
+        assert!(!res.has_gateway);
+    }
 }