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openzeppelin-contracts | OpenZeppelin Contracts is a library for secure smart | Blockchain library

 by   OpenZeppelin JavaScript Version: v4.6.0-rc.0 License: MIT

 by   OpenZeppelin JavaScript Version: v4.6.0-rc.0 License: MIT

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kandi X-RAY | openzeppelin-contracts Summary

openzeppelin-contracts is a JavaScript library typically used in Blockchain, Ethereum applications. openzeppelin-contracts has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can install using 'npm i openzeppelin-solidity' or download it from GitHub, npm.
A library for secure smart contract development. Build on a solid foundation of community-vetted code. :mage: Not sure how to get started? Check out Contracts Wizard — an interactive smart contract generator.
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kandi-support Support

  • openzeppelin-contracts has a medium active ecosystem.
  • It has 17136 star(s) with 8672 fork(s). There are 609 watchers for this library.
  • There were 1 major release(s) in the last 6 months.
  • There are 102 open issues and 1220 have been closed. On average issues are closed in 17 days. There are 31 open pull requests and 0 closed requests.
  • It has a neutral sentiment in the developer community.
  • The latest version of openzeppelin-contracts is v4.6.0-rc.0
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This Library - Support
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quality kandi Quality

  • openzeppelin-contracts has 0 bugs and 0 code smells.
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Best in #Blockchain
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This Library - Quality
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securitySecurity

  • openzeppelin-contracts has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
  • openzeppelin-contracts code analysis shows 0 unresolved vulnerabilities.
  • There are 0 security hotspots that need review.
This Library - Security
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This Library - Security
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license License

  • openzeppelin-contracts is licensed under the MIT License. This license is Permissive.
  • Permissive licenses have the least restrictions, and you can use them in most projects.
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buildReuse

  • openzeppelin-contracts releases are available to install and integrate.
  • Deployable package is available in npm.
  • Installation instructions, examples and code snippets are available.
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Top functions reviewed by kandi - BETA

kandi has reviewed openzeppelin-contracts and discovered the below as its top functions. This is intended to give you an instant insight into openzeppelin-contracts implemented functionality, and help decide if they suit your requirements.

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openzeppelin-contracts Key Features

Implementations of standards like ERC20 and ERC721.

Flexible role-based permissioning scheme.

Reusable Solidity components to build custom contracts and complex decentralized systems.

Installation

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$ npm install @openzeppelin/contracts

Usage

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pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";

contract MyCollectible is ERC721 {
    constructor() ERC721("MyCollectible", "MCO") {
    }
}

I'm trying to implement openzeppelin's minimal proxy clone contract on TRON blockchain

copy iconCopydownload iconDownload
keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))
(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN
    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }
-----------------------
keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))
(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN
    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }
-----------------------
keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))
(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN
    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }
-----------------------
keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))
(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN
    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }
-----------------------
keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))
0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))
(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN
    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }

What are the rules (syntax) for importing from Github repo to Solidity Contract

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import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol";

ParserError: Source file requires different compiler version

copy iconCopydownload iconDownload
pragma solidity >=0.4.22 <0.9.0;
 pragma solidity >=0.4.22 <0.8.0;
-----------------------
pragma solidity >=0.4.22 <0.9.0;
 pragma solidity >=0.4.22 <0.8.0;
-----------------------
function FulfillRandomness(bytes32 _requestId, uint256 _randomness)
        internal
        override
-----------------------
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.9.0;

Is it possible to call a ERC20 function inside a ERC721 contract?

copy iconCopydownload iconDownload
// Inside the nfts contract
ERC20 token = ERC20("your token address here");
token.transferFrom("args");
-----------------------
// Inside the nfts contract
ERC20 token = ERC20("your token address here");
token.transferFrom("args");
-----------------------
import "../interfaces/IERC20.sol";
function stakeTokens(uint256 _amount,address _token) public{
    // add require staments
    // IERC20(_token) this will initialize the contract
    IERC20(_token).transferFrom(msg.sender,address(this),_amount);
 }
-----------------------
import "../interfaces/IERC20.sol";
function stakeTokens(uint256 _amount,address _token) public{
    // add require staments
    // IERC20(_token) this will initialize the contract
    IERC20(_token).transferFrom(msg.sender,address(this),_amount);
 }

Sending ERC20 tokens using the transfer function

copy iconCopydownload iconDownload
constructor() {
      // payable allows payment of ether with a call.
      owner = payable(msg.sender);
  }
  require(msg.sender == owner, "Only owner can withdraw funds"); 
  require(amount <= balance, "Insufficient funds");
-----------------------
constructor() {
      // payable allows payment of ether with a call.
      owner = payable(msg.sender);
  }
  require(msg.sender == owner, "Only owner can withdraw funds"); 
  require(amount <= balance, "Insufficient funds");

How to add tokenomics to a ERC20 token?

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function _transfer(address sender, address recipient, uint256 amount) private {
    require(sender != address(0), "BEP20: transfer from the zero address");
    require(balanceOf(sender) >= amount, "BEP2': not enough balance");
    
    uint256 tokensToBurn = amount.mul(burningFee).div(100);
    amount = amount.sub(tokensToBurn);

    balances[sender] = balances[sender].sub(amount);

    _burn(sender, tokensToBurn);
    balances[recipient] = balances[recipient].add(amount);
    
}

Member &quot;transfer&quot; not found or not visible

copy iconCopydownload iconDownload
firstContract._admin.transfer(value);
address payable public _admin;
firstContract._admin().transfer(value);
constructor(address _address) payable {
-----------------------
firstContract._admin.transfer(value);
address payable public _admin;
firstContract._admin().transfer(value);
constructor(address _address) payable {
-----------------------
firstContract._admin.transfer(value);
address payable public _admin;
firstContract._admin().transfer(value);
constructor(address _address) payable {
-----------------------
firstContract._admin.transfer(value);
address payable public _admin;
firstContract._admin().transfer(value);
constructor(address _address) payable {

SOLIDITY: Trying to get working Mapping/Struct for giving a &quot;player&quot; multiple &quot;tickets&quot;, problem(s) with array

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picket.ticket = [1,2,3,4,5];
picket.ticket = [uint256(1), 2, 3, 4, 5, 0];
-----------------------
picket.ticket = [1,2,3,4,5];
picket.ticket = [uint256(1), 2, 3, 4, 5, 0];

Solidity BEP20 : transferFrom not (or not yet) declared or visible at this point

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function transferFrom(address sender, address recipient, uint256 amount) external returns (bool) {
                                                                       //^ external functions are 
//called just from outside the contract (even another contract inherits it, can not use this function)

I'm getting an error, a declaration error but its pointing to something in quotes which i don't understand

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pragma solidity ^0.8.6;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/access/Ownable.sol";

contract Allowance is Ownable {
    mapping(address => uint256) public allowance;

    // This will fix compile error, or, need use inheritance to prevent duplicate code.
    function isOwner() internal view returns (bool) {
        return owner() == msg.sender;
    }

    function addAllowance(address _who, uint256 _amount) public onlyOwner {
        allowance[_who] = _amount;
    }

    modifier ownerOrAllowed(uint256 _amount) {
        require(
            isOwner() || allowance[msg.sender] >= _amount,
            "You are not allowed!"
        );
        _;
    }

    function reduceAllowance(address _who, uint256 _amount)
        internal
        ownerOrAllowed(_amount)
    {
        allowance[_who] -= _amount;
    }
}

contract SharedWallet is Allowance {
    uint256 public balanceReceived;

    function sendEther() public payable {
        balanceReceived += msg.value;
    }

    function isOwner() internal view returns (bool) {
        return owner() == msg.sender;
    }

    function withdrawMoney(address payable _to, uint256 _amount)
        public
        ownerOrAllowed(_amount)
    {
        require(
            _amount <= address(this).balance,
            "not enough funds in contract"
        );
        if (!isOwner()) {
            reduceAllowance(msg.sender, _amount);
        }
        _to.transfer(_amount);
    }

    fallback() external payable {}
}

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QUESTION

I'm trying to implement openzeppelin's minimal proxy clone contract on TRON blockchain

Asked 2022-Mar-23 at 03:33

The openzeppelin minimal proxy contract here has this function predictDeterministicAddress() that hashes values like the sender's address, a salt... to generate a contract address that the create2 function will also generate, when its passed the same values as dictated in this EIP.

This EIP states that an arbitrary value 0xff when hashed with a salt, senders address and the contract bytecode will always generate the same address.

Im trying to implement the predictDeterministicAddress() function on TRON blockchain but the TRON docs specify a different arbitrary value, 0x41 for implementing this same feature.
I tried to just replace the values but i can't see where the openzeppelin team used the value 0xff in their function.

Below is the openzeppelin hashing function:

    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf3ff00000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }

Also due to my limited knowledge of assembly i cant fully grasp how their hashing function works exactly.

Can anyone explain to me, or help me understand how that function can be implemented on the TRON blockchain to the desired effect?

Basically i want to be able to pass the same values to create2 and also to this function on the TRON blockchain, and generate the same contract address.

ANSWER

Answered 2022-Mar-23 at 03:33

According to solidity's official documentation (https://docs.soliditylang.org/en/latest/control-structures.html?highlight=create2#salted-contract-creations-create2), the algorithm for calculating create2 addresses should be as follows:

keccak256(bytes1(0xff) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))

But on TRON, the algorithm should be as follows:

keccak256(bytes1(0x41) ++ address(factory_contract) 
    ++ bytes32(salt) ++ keccak256(bytes(creation_code) ++ bytes(arg...)))

The difference is that the first byte given to the outer keccak256 function. EVM in ethereum is 0xff, TVM in TRON is 0x41.

Before calculating the predicted address( predicted := keccak256(add(ptr, 0x37), 0x55) ), starting from (ptr), memory data:

0x00 ~ 0x13 3d602d80600a3d3981f3363d3d373d3d3d363d73 
0x14 ~ 0x27 (implementation address)
0x28 ~ 0x37 5af43d82803e903d91602b57fd5bf3 ff (This byte is the key, should be replaced by 0x41 on TRON)
0x38 ~ 0x4b (deployer address)
0x4c ~ 0x6b (salt bytes32)
0x6c ~ 0x8b (keccak256(0x00 ~ 0x37)) (This part hash is keccak256(bytes(creation_code) ++ bytes(arg...)))

This means that creation code for proxy contract will be 0x3d602d80600a3d3981f3363d3d373d3d3d363d73(impl)5af43d82803e903d91602b57fd5bf3. We can decompile this code on (https://ethervm.io/decompile), the results are as follows:

(implementation address is replaced by 0xea674fdde714fd979de3edf0f56aa9716b898ec8)

label_0000:
    // Inputs[3]
    // {
    //     @0000  returndata.length
    //     @0006  returndata.length
    //     @0009  memory[returndata.length:returndata.length + 0x2d]
    // }
    0000    3D  RETURNDATASIZE
    0001    60  PUSH1 0x2d
    0003    80  DUP1
    0004    60  PUSH1 0x0a
    0006    3D  RETURNDATASIZE
    0007    39  CODECOPY
    0008    81  DUP2
    0009    F3  *RETURN
    // Stack delta = +1
    // Outputs[3]
    // {
    //     @0000  stack[0] = returndata.length
    //     @0007  memory[returndata.length:returndata.length + 0x2d] = code[0x0a:0x37]
    //     @0009  return memory[returndata.length:returndata.length + 0x2d];
    // }
    // Block terminates

    000A    36    CALLDATASIZE
    000B    3D    RETURNDATASIZE
    000C    3D    RETURNDATASIZE
    000D    37    CALLDATACOPY
    000E    3D    RETURNDATASIZE
    000F    3D    RETURNDATASIZE
    0010    3D    RETURNDATASIZE
    0011    36    CALLDATASIZE
    0012    3D    RETURNDATASIZE
    0013    73    PUSH20 0xea674fdde714fd979de3edf0f56aa9716b898ec8
    0028    5A    GAS
    0029    F4    DELEGATECALL
    002A    3D    RETURNDATASIZE
    002B    82    DUP3
    002C    80    DUP1
    002D    3E    RETURNDATACOPY
    002E    90    SWAP1
    002F    3D    RETURNDATASIZE
    0030    91    SWAP2
    0031    60    PUSH1 0x2b
    0033    57    *JUMPI
    0034    FD    *REVERT
    0035    5B    JUMPDEST
    0036    F3    *RETURN

The openzeppelin hashing function should be adjusted on TRON as follows:

    /**
     * @dev Computes the address of a clone deployed using {Clones-cloneDeterministic}.
     */
    function predictDeterministicAddress(
        address implementation,
        bytes32 salt,
        address deployer
    ) internal pure returns (address predicted) {
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(ptr, 0x14), shl(0x60, implementation))
            mstore(add(ptr, 0x28), 0x5af43d82803e903d91602b57fd5bf34100000000000000000000000000000000)
            mstore(add(ptr, 0x38), shl(0x60, deployer))
            mstore(add(ptr, 0x4c), salt)
            mstore(add(ptr, 0x6c), keccak256(ptr, 0x37))
            predicted := keccak256(add(ptr, 0x37), 0x55)
        }
    }

Source https://stackoverflow.com/questions/71573083

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