init commit for onechain dex

CMakeLists.txt

@@ -0,0 +1,8 @@
+file(GLOB ABI_FILES "*.abi")
+configure_file("${ABI_FILES}" "${CMAKE_CURRENT_BINARY_DIR}" COPYONLY)
+
+add_wast_executable(TARGET exchange
+        INCLUDE_FOLDERS "${STANDARD_INCLUDE_FOLDERS}"
+        LIBRARIES libc libc++ eosiolib
+        DESTINATION_FOLDER ${CMAKE_CURRENT_BINARY_DIR}
+        )

exchange.abi

@@ -0,0 +1,77 @@
+{
+  "____comment": "This file was generated by eosio-abigen. DO NOT EDIT - 2018-09-25T10:15:30",
+  "version": "eosio::abi/1.0",
+  "types": [],
+  "structs": [{
+      "name": "orders",
+      "base": "",
+      "fields": [{
+          "name": "id",
+          "type": "uint64"
+        },{
+          "name": "price",
+          "type": "uint64"
+        },{
+          "name": "quantity",
+          "type": "asset"
+        },{
+          "name": "maker",
+          "type": "name"
+        }
+      ]
+    },{
+      "name": "bid",
+      "base": "",
+      "fields": [{
+          "name": "maker",
+          "type": "name"
+        },{
+          "name": "quantity",
+          "type": "asset"
+        },{
+          "name": "price",
+          "type": "uint64"
+        }
+      ]
+    },{
+      "name": "ask",
+      "base": "",
+      "fields": [{
+          "name": "maker",
+          "type": "name"
+        },{
+          "name": "quantity",
+          "type": "asset"
+        },{
+          "name": "price",
+          "type": "uint64"
+        }
+      ]
+    }
+  ],
+  "actions": [{
+      "name": "bid",
+      "type": "bid",
+      "ricardian_contract": ""
+    },{
+      "name": "ask",
+      "type": "ask",
+      "ricardian_contract": ""
+    }
+  ],
+  "tables": [{
+      "name": "orders",
+      "index_type": "i64",
+      "key_names": [
+        "id"
+      ],
+      "key_types": [
+        "uint64"
+      ],
+      "type": "orders"
+    }
+  ],
+  "ricardian_clauses": [],
+  "error_messages": [],
+  "abi_extensions": []
+}

exchange.cpp

@@ -0,0 +1,172 @@
+/**
+ * simple decentralized exchange
+ * smart contract on eos
+ *
+ */
+
+#include "exchange.hpp"
+
+using namespace eosio;
+
+void exchange::add_order(uint64_t scope, account_name maker, asset quantity, uint64_t price) {
+    order_index orders(_self, scope);
+    print("add order, maker: ", name{maker}, " quantity: ", quantity, " price: ", asset(price, settlement_token_symbol),
+          "\n");
+    if (quantity.amount > 0) {
+        orders.emplace(maker, [&](auto &r) {
+            r.id = orders.available_primary_key();
+            r.price = price;
+            r.quantity = quantity;
+            r.maker = maker;
+        });
+    }
+}
+
+void exchange::deposit(account_name contract, account_name user, asset quantity) {
+    print(name{user}, " deposit ", quantity, "\n");
+    if (quantity.amount == 0) {
+        print("amoutn equals to 0 abord\n");
+        return;
+    }
+    action(
+            permission_level{user, N(active)},
+            contract, N(transfer),
+            std::make_tuple(user, _self, quantity, std::string("deposit"))
+    ).send();
+}
+
+void exchange::transfer(account_name contract, account_name from, account_name to, asset quantity) {
+    print(name{from}, " transfer ", quantity, " to ", name{to}, "\n");
+    action(
+            permission_level{from, N(active)},
+            contract, N(transfer),
+            std::make_tuple(from, to, quantity, std::string("transfer"))
+    ).send();
+}
+
+void exchange::withdraw(account_name contract, account_name user, asset quantity) {
+    print(name{user}, " withdraw ", quantity, "\n");
+    if (quantity.amount == 0) {
+        print("amoutn equals to 0 abord\n");
+        return;
+    }
+    action(
+            permission_level{_self, N(active)},
+            contract, N(transfer),
+            std::make_tuple(_self, user, quantity, std::string("withdraw"))
+    ).send();
+}
+
+asset exchange::to_settlement_token(asset quantity, uint64_t price, bool floor) {
+    //this is a simple logic, need to add more rules
+    uint64_t amt = quantity.amount * price;
+
+    int64_t p = (int64_t) quantity.symbol.precision();
+    int64_t p10 = 1;
+
+    while (p > 0) {
+        p10 *= 10;
+        --p;
+    }
+    // this arithmetician work for eos rule like eos.amount*10000
+    uint64_t res = amt / p10;
+
+    if (!floor && res * p10 != amt)
+        res++;
+    return asset(res, settlement_token_symbol);
+}
+
+asset exchange::asset_min(asset a, asset b) {
+    if (a > b) return b;
+    else return a;
+}
+
+//sell
+void exchange::ask(account_name maker, asset quantity, uint64_t price) {
+    //充值其他代币，卖
+    //deposit(exchange_token_contract, maker, quantity);
+
+    //查找所有的买单
+    order_index bid_orders(_self, N(bid));
+    //查找所有买价高于price的买方按照价格时间排序
+    auto bid_orders_by_price = bid_orders.get_index<N(byprice)>();
+    //买单不存在的表示
+    auto bid_it = bid_orders_by_price.end();
+    //获取符合条件的买单的迭代器
+    auto bid_end = bid_orders_by_price.lower_bound(price);
+
+    auto left = quantity;
+    asset maker_receive(0, settlement_token_symbol);
+
+    while (left.amount > 0 && bid_it != bid_end) {
+        bid_it--;
+        print("bid order id: ", bid_it->id, " price: ", bid_it->price, "\n");
+
+        auto exchange_quantity = asset_min(bid_it->quantity, left);
+
+        auto settlement_token_quantity = to_settlement_token(exchange_quantity, price, true);
+
+        maker_receive += settlement_token_quantity;
+        //withdraw(exchange_token_contract, bid_it->maker, exchange_quantity);
+        transfer(exchange_token_contract, maker, bid_it->maker, exchange_quantity);
+
+        left -= exchange_quantity;
+
+        if (bid_it->quantity == exchange_quantity) {
+            bid_it = bid_orders_by_price.erase(bid_it);
+        } else {
+            bid_orders_by_price.modify(bid_it, maker, [&](auto &r) {
+                r.quantity -= exchange_quantity;
+            });
+        }
+    }
+    deposit(exchange_token_contract, maker, left);
+    add_order(N(ask), maker, left, price);
+
+    withdraw(settlement_token_contract, maker, maker_receive);
+}
+
+//buy
+void exchange::bid(account_name maker, asset quantity, uint64_t price) {
+    //充值eos
+    //deposit(settlement_token_contract, maker, to_settlement_token(quantity, price, false));
+
+    //查找对手
+    order_index ask_orders(_self, N(ask));
+    //查找所有卖价低于price的卖方按照价格时间排序
+    auto ask_orders_by_price = ask_orders.get_index<N(byprice)>();
+    auto ask_it = ask_orders_by_price.begin();
+    auto ask_end = ask_orders_by_price.upper_bound(price);
+
+    auto left = quantity;
+    asset maker_receive(0, exchange_token_symbol);
+
+    while (left.amount > 0 && ask_it != ask_end) {
+        print("ask order id: ", ask_it->id, " price: ", ask_it->price, "\n");
+
+        auto exchange_quantity = asset_min(ask_it->quantity, left);
+
+        auto settlement_token_quantity = to_settlement_token(exchange_quantity, ask_it->price, false);
+
+        maker_receive += exchange_quantity;
+        //withdraw(settlement_token_contract, ask_it->maker, settlement_token_quantity);
+        transfer(settlement_token_contract, maker, ask_it->maker, settlement_token_quantity);
+
+        left -= exchange_quantity;
+
+        if (ask_it->quantity == exchange_quantity) {
+            ask_it = ask_orders_by_price.erase(ask_it);
+        } else {
+            ask_orders_by_price.modify(ask_it, maker, [&](auto &r) {
+                r.quantity -= exchange_quantity;
+            });
+            ask_it++;
+        }
+    }
+    deposit(settlement_token_contract, maker, to_settlement_token(left, price, false));
+    add_order(N(bid), maker, left, price);
+
+    withdraw(exchange_token_contract, maker, maker_receive);
+}
+
+EOSIO_ABI(exchange, (bid)(ask))

src/exchange.hpp → exchange.hpp

@@ -23,10 +23,12 @@ class exchange : public contract {
     void ask(account_name maker, asset quantity, uint64_t price);
 
     //token contract is not eosio.token it is the op
-    account_name settlement_token_contract = N(eosio.token);
+//    account_name settlement_token_contract = N(eosio.token);
+    account_name settlement_token_contract = N(onedexchange);
     symbol_type settlement_token_symbol = S(4, EOS);
 
-    account_name exchange_token_contract = N(eosio.token);
+    account_name exchange_token_contract = N(onedechange);
+//    account_name exchange_token_contract = N(eosio.token);
     symbol_type exchange_token_symbol = S(3, SYS);
 
   private:
@@ -54,3 +56,4 @@ class exchange : public contract {
     asset to_settlement_token(asset quantity, uint64_t price, bool floor);
     asset asset_min(asset a, asset b);
 };
+