github.com/iotexproject/iotex-core@v1.14.1-rc1/action/protocol/execution/testdata-istanbul/write-protection-004.sol (about)

     1  // SPDX-License-Identifier: MIT
     2  pragma solidity ^0.6.6;
     3  
     4  // NOTE: Deploy this contract first
     5  contract B {
     6      // NOTE: storage layout must be the same as contract A
     7      uint public num;
     8      address public sender;
     9      uint public value;
    10      mapping(uint => uint) private _a;
    11      event Done();
    12  
    13      constructor() public {
    14          _a[1] = 1;
    15          _a[2] = 2;
    16          _a[3] = 3;
    17      }
    18  
    19      function setVars(uint _num) public payable {
    20          if (_num == 0) {
    21              delete _a[1];
    22              delete _a[2];
    23          }
    24          num = _num;
    25          sender = msg.sender;
    26          value = msg.value;
    27          emit Done();
    28      }
    29  }
    30  
    31  contract A {
    32      uint public num;
    33      address public sender;
    34      uint public value;
    35      address private c;
    36      mapping(uint => uint) private _a;
    37      event Success(bool);
    38  
    39      function make() public {
    40          c = address(new B());
    41          _a[1] = 1;
    42          _a[2] = 2;
    43          _a[3] = 3;
    44      }
    45  
    46      function callStatic(address _contract,uint _num) public {
    47          if (_num == 0) {
    48              _contract.call(
    49                  abi.encodeWithSignature("notfund()")
    50              );
    51              delete _a[1];
    52              delete _a[2];
    53          }
    54          if (_num == 1) {
    55              delete _a[3];
    56          }
    57          (bool success, bytes memory _) = _contract.staticcall(
    58              abi.encodeWithSignature("setVars(uint256)", _num)
    59          );
    60          emit Success(success);
    61          if (_num == 0) {
    62              revert();
    63          }
    64          if (_num == 1) {
    65              selfdestruct(address(0));
    66          }
    67          // 0x0000000000000000000000000000000000000000.call(
    68          //     abi.encodeWithSignature("notfund()")
    69          // );
    70      }
    71  
    72      function setVars(address _contract, uint _num) public returns (uint256) {
    73          if (_contract == address(0)) {
    74              _contract = c;
    75          }
    76          try this.callStatic(_contract,0) {
    77          } catch {
    78              this.callStatic(_contract,1);
    79          }
    80  
    81          return 1;
    82      }
    83  }