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dodo-contractV2/contracts/DODOVendingMachine/impl/DVMFunding.sol
2020-11-29 23:47:39 +08:00

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/*
Copyright 2020 DODO ZOO.
SPDX-License-Identifier: Apache-2.0
*/
pragma solidity 0.6.9;
pragma experimental ABIEncoderV2;
import {DVMVault} from "./DVMVault.sol";
import {DecimalMath} from "../../lib/DecimalMath.sol";
import {IDODOCallee} from "../../intf/IDODOCallee.sol";
contract DVMFunding is DVMVault {
// ============ Events ============
event BuyShares(address indexed user, uint256 increaseShares, uint256 totalShares);
event SellShares(address indexed user, uint256 decreaseShares, uint256 totalShares);
// ============ Buy & Sell Shares ============
// buy shares [round down]
function buyShares(address to)
external
preventReentrant
returns (
uint256 shares,
uint256 baseInput,
uint256 quoteInput
)
{
uint256 baseBalance = _BASE_TOKEN_.balanceOf(address(this));
uint256 quoteBalance = _QUOTE_TOKEN_.balanceOf(address(this));
uint256 baseReserve = _BASE_RESERVE_;
uint256 quoteReserve = _QUOTE_RESERVE_;
baseInput = baseBalance.sub(baseReserve);
quoteInput = quoteBalance.sub(quoteReserve);
require(baseInput > 0, "NO_BASE_INPUT");
// case 1. initial supply
// 包含了 baseReserve == 0 && quoteReserve == 0 的情况
// 在提币的时候向下取整。因此永远不会出现balance为0但totalsupply不为0的情况
// 但有可能出现reserve>0但totalSupply=0的场景
if (totalSupply == 0) {
shares = baseBalance; // 以免出现balance很大但shares很小的情况
} else if (baseReserve > 0 && quoteReserve == 0) {
// case 2. supply when quote reserve is 0
shares = baseInput.mul(totalSupply).div(baseReserve);
} else if (baseReserve > 0 && quoteReserve > 0) {
// case 3. normal case
uint256 baseInputRatio = DecimalMath.divFloor(baseInput, baseReserve);
uint256 quoteInputRatio = DecimalMath.divFloor(quoteInput, quoteReserve);
uint256 mintRatio = quoteInputRatio < baseInputRatio ? quoteInputRatio : baseInputRatio;
shares = DecimalMath.mulFloor(totalSupply, mintRatio);
}
_mint(to, shares);
_sync();
emit BuyShares(to, shares, _SHARES_[to]);
}
// sell shares [round down]
function sellShares(
uint256 shareAmount,
address to,
uint256 baseMinAmount,
uint256 quoteMinAmount,
bytes calldata data,
uint256 deadline
) external preventReentrant returns (uint256 baseAmount, uint256 quoteAmount) {
require(deadline >= block.timestamp, 'DODOV2 DVMFUNDING: EXPIRED');
require(shareAmount <= _SHARES_[msg.sender], "DLP_NOT_ENOUGH");
uint256 baseBalance = _BASE_TOKEN_.balanceOf(address(this));
uint256 quoteBalance = _QUOTE_TOKEN_.balanceOf(address(this));
uint256 totalShares = totalSupply;
baseAmount = baseBalance.mul(shareAmount).div(totalShares);
quoteAmount = quoteBalance.mul(shareAmount).div(totalShares);
require(
baseAmount >= baseMinAmount && quoteAmount >= quoteMinAmount,
"WITHDRAW_NOT_ENOUGH"
);
_burn(msg.sender, shareAmount);
_transferBaseOut(to, baseAmount);
_transferQuoteOut(to, quoteAmount);
if (data.length > 0) {
IDODOCallee(to).DVMSellShareCall(
msg.sender,
shareAmount,
baseAmount,
quoteAmount,
data
);
}
_sync();
}
}