Allow create/top up with cw20 tokens

contracts/cw20-escrow/examples/schema.rs

@@ -3,7 +3,7 @@ use std::fs::create_dir_all;
 
 use cosmwasm_schema::{export_schema, remove_schemas, schema_for};
 
-use cw20_escrow::msg::{DetailsResponse, HandleMsg, InitMsg, ListResponse, QueryMsg};
+use cw20_escrow::msg::{DetailsResponse, HandleMsg, InitMsg, ListResponse, QueryMsg, ReceiveMsg};
 
 fn main() {
     let mut out_dir = current_dir().unwrap();
@@ -14,6 +14,7 @@ fn main() {
     export_schema(&schema_for!(InitMsg), &out_dir);
     export_schema(&schema_for!(HandleMsg), &out_dir);
     export_schema(&schema_for!(QueryMsg), &out_dir);
+    export_schema(&schema_for!(ReceiveMsg), &out_dir);
     export_schema(&schema_for!(DetailsResponse), &out_dir);
     export_schema(&schema_for!(ListResponse), &out_dir);
 }

contracts/cw20-escrow/schema/handle_msg.json

@@ -13,6 +13,26 @@
         }
       }
     },
+    {
+      "description": "Adds all sent native tokens to the contract",
+      "type": "object",
+      "required": [
+        "top_up"
+      ],
+      "properties": {
+        "top_up": {
+          "type": "object",
+          "required": [
+            "id"
+          ],
+          "properties": {
+            "id": {
+              "type": "string"
+            }
+          }
+        }
+      }
+    },
     {
       "description": "Approve sends all tokens to the recipient. Only the arbiter can do this",
       "type": "object",
@@ -54,9 +74,25 @@
           }
         }
       }
+    },
+    {
+      "description": "This accepts a properly-encoded ReceiveMsg from a cw20 contract",
+      "type": "object",
+      "required": [
+        "receive"
+      ],
+      "properties": {
+        "receive": {
+          "$ref": "#/definitions/Cw20ReceiveMsg"
+        }
+      }
     }
   ],
   "definitions": {
+    "Binary": {
+      "description": "Binary is a wrapper around Vec<u8> to add base64 de/serialization with serde. It also adds some helper methods to help encode inline.\n\nThis is only needed as serde-json-{core,wasm} has a horrible encoding for Vec<u8>",
+      "type": "string"
+    },
     "CreateMsg": {
       "type": "object",
       "required": [
@@ -105,8 +141,37 @@
         }
       }
     },
+    "Cw20ReceiveMsg": {
+      "description": "Cw20ReceiveMsg should be de/serialized under `Receive()` variant in a HandleMsg",
+      "type": "object",
+      "required": [
+        "amount",
+        "sender"
+      ],
+      "properties": {
+        "amount": {
+          "$ref": "#/definitions/Uint128"
+        },
+        "msg": {
+          "anyOf": [
+            {
+              "$ref": "#/definitions/Binary"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
+        "sender": {
+          "$ref": "#/definitions/HumanAddr"
+        }
+      }
+    },
     "HumanAddr": {
       "type": "string"
+    },
+    "Uint128": {
+      "type": "string"
     }
   }
 }

contracts/cw20-escrow/schema/receive_msg.json

@@ -0,0 +1,90 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "title": "ReceiveMsg",
+  "anyOf": [
+    {
+      "type": "object",
+      "required": [
+        "create"
+      ],
+      "properties": {
+        "create": {
+          "$ref": "#/definitions/CreateMsg"
+        }
+      }
+    },
+    {
+      "description": "Adds all sent native tokens to the contract",
+      "type": "object",
+      "required": [
+        "top_up"
+      ],
+      "properties": {
+        "top_up": {
+          "type": "object",
+          "required": [
+            "id"
+          ],
+          "properties": {
+            "id": {
+              "type": "string"
+            }
+          }
+        }
+      }
+    }
+  ],
+  "definitions": {
+    "CreateMsg": {
+      "type": "object",
+      "required": [
+        "arbiter",
+        "id",
+        "recipient"
+      ],
+      "properties": {
+        "arbiter": {
+          "description": "arbiter can decide to approve or refund the escrow",
+          "allOf": [
+            {
+              "$ref": "#/definitions/HumanAddr"
+            }
+          ]
+        },
+        "end_height": {
+          "description": "When end height set and block height exceeds this value, the escrow is expired. Once an escrow is expired, it can be returned to the original funder (via \"refund\").",
+          "type": [
+            "integer",
+            "null"
+          ],
+          "format": "uint64",
+          "minimum": 0.0
+        },
+        "end_time": {
+          "description": "When end time (in seconds since epoch 00:00:00 UTC on 1 January 1970) is set and block time exceeds this value, the escrow is expired. Once an escrow is expired, it can be returned to the original funder (via \"refund\").",
+          "type": [
+            "integer",
+            "null"
+          ],
+          "format": "uint64",
+          "minimum": 0.0
+        },
+        "id": {
+          "description": "id is a human-readable name for the escrow to use later 3-20 bytes of utf-8 text",
+          "type": "string"
+        },
+        "recipient": {
+          "description": "if approved, funds go to the recipient",
+          "allOf": [
+            {
+              "$ref": "#/definitions/HumanAddr"
+            }
+          ]
+        }
+      }
+    },
+    "HumanAddr": {
+      "type": "string"
+    }
+  }
+}

contracts/cw20-escrow/src/contract.rs

@@ -1,11 +1,12 @@
 use cosmwasm_std::{
-    log, to_binary, Api, BankMsg, Binary, Coin, CosmosMsg, Env, Extern, HandleResponse, HumanAddr,
-    InitResponse, Querier, StdError, StdResult, Storage, WasmMsg,
+    from_binary, log, to_binary, Api, BankMsg, Binary, Coin, CosmosMsg, Env, Extern,
+    HandleResponse, HumanAddr, InitResponse, Querier, StdError, StdResult, Storage, WasmMsg,
 };
-use cw20::Cw20HandleMsg;
+use cw20::{Cw20HandleMsg, Cw20ReceiveMsg};
 
 use crate::msg::{
     CreateMsg, Cw20CoinHuman, DetailsResponse, HandleMsg, InitMsg, ListResponse, QueryMsg,
+    ReceiveMsg,
 };
 use crate::state::{all_escrow_ids, escrows, escrows_read, Cw20Coin, Escrow, PREFIX_ESCROW};
 use cosmwasm_storage::prefixed;
@@ -29,6 +30,27 @@ pub fn handle<S: Storage, A: Api, Q: Querier>(
         HandleMsg::Approve { id } => try_approve(deps, env, id),
         HandleMsg::TopUp { id } => try_top_up(deps, env, id),
         HandleMsg::Refund { id } => try_refund(deps, env, id),
+        HandleMsg::Receive(msg) => try_receive(deps, env, msg),
+    }
+}
+
+pub fn try_receive<S: Storage, A: Api, Q: Querier>(
+    deps: &mut Extern<S, A, Q>,
+    env: Env,
+    wrapper: Cw20ReceiveMsg,
+) -> StdResult<HandleResponse> {
+    let msg: ReceiveMsg = match wrapper.msg {
+        Some(bin) => from_binary(&bin),
+        None => Err(StdError::parse_err("ReceiveMsg", "no data")),
+    }?;
+    // TODO: assert the sending token address is valid (contract not external account)
+    let token = Cw20Coin {
+        address: env.message.sender,
+        amount: wrapper.amount,
+    };
+    match msg {
+        ReceiveMsg::Create(create) => try_cw20_create(deps, wrapper.sender, token, create),
+        ReceiveMsg::TopUp { id } => try_cw20_top_up(deps, wrapper.sender, token, id),
     }
 }
 
@@ -65,6 +87,34 @@ pub fn try_create<S: Storage, A: Api, Q: Querier>(
     Ok(res)
 }
 
+pub fn try_cw20_create<S: Storage, A: Api, Q: Querier>(
+    deps: &mut Extern<S, A, Q>,
+    sender: HumanAddr,
+    token: Cw20Coin,
+    msg: CreateMsg,
+) -> StdResult<HandleResponse> {
+    let escrow = Escrow {
+        arbiter: deps.api.canonical_address(&msg.arbiter)?,
+        recipient: deps.api.canonical_address(&msg.recipient)?,
+        source: deps.api.canonical_address(&sender)?,
+        end_height: msg.end_height,
+        end_time: msg.end_time,
+        // there are native coins sent with the message
+        native_balance: vec![],
+        cw20_balance: vec![token],
+    };
+
+    // try to store it, fail if the id was already in use
+    escrows(&mut deps.storage).update(msg.id.as_bytes(), |existing| match existing {
+        None => Ok(escrow),
+        Some(_) => Err(StdError::generic_err("escrow id already in use")),
+    })?;
+
+    let mut res = HandleResponse::default();
+    res.log = vec![log("action", "create"), log("id", msg.id)];
+    Ok(res)
+}
+
 pub fn try_top_up<S: Storage, A: Api, Q: Querier>(
     deps: &mut Extern<S, A, Q>,
     env: Env,
@@ -75,6 +125,27 @@ pub fn try_top_up<S: Storage, A: Api, Q: Querier>(
 
     // combine these two
     add_tokens(&mut escrow.native_balance, env.message.sent_funds);
+    // and save
+    escrows(&mut deps.storage).save(id.as_bytes(), &escrow)?;
+
+    let mut res = HandleResponse::default();
+    res.log = vec![log("action", "top_up"), log("id", id)];
+    Ok(res)
+}
+
+pub fn try_cw20_top_up<S: Storage, A: Api, Q: Querier>(
+    deps: &mut Extern<S, A, Q>,
+    _sender: HumanAddr,
+    token: Cw20Coin,
+    id: String,
+) -> StdResult<HandleResponse> {
+    // this fails is no escrow there
+    let mut escrow = escrows_read(&deps.storage).load(id.as_bytes())?;
+
+    // combine these two
+    add_cw20_token(&mut escrow.cw20_balance, token);
+    // and save
+    escrows(&mut deps.storage).save(id.as_bytes(), &escrow)?;
 
     let mut res = HandleResponse::default();
     res.log = vec![log("action", "top_up"), log("id", id)];
@@ -97,6 +168,20 @@ fn add_tokens(store: &mut Vec<Coin>, add: Vec<Coin>) {
     }
 }
 
+fn add_cw20_token(store: &mut Vec<Cw20Coin>, token: Cw20Coin) {
+    let index = store.iter().enumerate().find_map(|(i, exist)| {
+        if exist.address == token.address {
+            Some(i)
+        } else {
+            None
+        }
+    });
+    match index {
+        Some(idx) => store[idx].amount += token.amount,
+        None => store.push(token),
+    }
+}
+
 pub fn try_approve<S: Storage, A: Api, Q: Querier>(
     deps: &mut Extern<S, A, Q>,
     env: Env,

contracts/cw20-escrow/src/msg.rs

@@ -1,4 +1,5 @@
 use cosmwasm_std::{Coin, HumanAddr, Uint128};
+use cw20::Cw20ReceiveMsg;
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
@@ -25,6 +26,18 @@ pub enum HandleMsg {
         /// id is a human-readable name for the escrow from create
         id: String,
     },
+    /// This accepts a properly-encoded ReceiveMsg from a cw20 contract
+    Receive(Cw20ReceiveMsg),
+}
+
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+#[serde(rename_all = "snake_case")]
+pub enum ReceiveMsg {
+    Create(CreateMsg),
+    /// Adds all sent native tokens to the contract
+    TopUp {
+        id: String,
+    },
 }
 
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]