Fix contract detection (of name, symbol, decimals, balance) to handle ERC721 not having name and symbol. Also refactoring
Hwee-Boon Yar
3 years ago
parent
7f3a158c4f
commit
a540450678
@ -0,0 +1,171 @@ |
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// Copyright © 2021 Stormbird PTE. LTD. |
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import Foundation |
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import Alamofire |
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import PromiseKit |
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enum ContractData { |
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case name(String) |
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case symbol(String) |
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case balance(balance: [String], tokenType: TokenType) |
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case decimals(UInt8) |
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case nonFungibleTokenComplete(name: String, symbol: String, balance: [String], tokenType: TokenType) |
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case fungibleTokenComplete(name: String, symbol: String, decimals: UInt8) |
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case delegateTokenComplete |
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case failed(networkReachable: Bool?) |
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} |
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class ContractDataDetector { |
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private let address: AlphaWallet.Address |
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private let storage: TokensDataStore |
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private let assetDefinitionStore: AssetDefinitionStore |
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private let namePromise: Promise<String> |
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private let symbolPromise: Promise<String> |
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private let tokenTypePromise: Promise<TokenType> |
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private let (nonFungibleBalancePromise, nonFungibleBalanceSeal) = Promise<[String]>.pending() |
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private let (decimalsPromise, decimalsSeal) = Promise<UInt8>.pending() |
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private var failed = false |
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private var completion: ((ContractData) -> Void)? |
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init(address: AlphaWallet.Address, storage: TokensDataStore, assetDefinitionStore: AssetDefinitionStore) { |
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self.address = address |
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self.storage = storage |
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self.assetDefinitionStore = assetDefinitionStore |
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namePromise = storage.getContractName(for: address) |
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symbolPromise = storage.getContractSymbol(for: address) |
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tokenTypePromise = storage.getTokenType(for: address) |
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} |
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/// Failure to obtain contract data may be due to no-connectivity. So we should check .failed(networkReachable: Bool) |
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//Have to use strong self in promises below, otherwise `self` will be destroyed before fetching completes |
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func fetch(completion: @escaping (ContractData) -> Void) { |
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self.completion = completion |
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assetDefinitionStore.fetchXML(forContract: address) |
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firstly { |
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namePromise |
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}.done { name in |
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self.completionOfPartialData(.name(name)) |
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}.catch { error in |
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self.callCompletionFailed() |
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//We consider name and symbol and empty string because NFTs (ERC721 and ERC1155) don't have to implement `name` and `symbol`. Eg. ENS/721 (0x57f1887a8BF19b14fC0dF6Fd9B2acc9Af147eA85) and Enjin/1155 (0xfaafdc07907ff5120a76b34b731b278c38d6043c) |
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self.completionOfPartialData(.name("")) |
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} |
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firstly { |
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symbolPromise |
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}.done { symbol in |
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self.completionOfPartialData(.symbol(symbol)) |
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}.catch { error in |
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self.callCompletionFailed() |
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//We consider name and symbol and empty string because NFTs (ERC721 and ERC1155) don't have to implement `name` and `symbol`. Eg. ENS/721 (0x57f1887a8BF19b14fC0dF6Fd9B2acc9Af147eA85) and Enjin/1155 (0xfaafdc07907ff5120a76b34b731b278c38d6043c) |
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self.completionOfPartialData(.symbol("")) |
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} |
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firstly { |
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tokenTypePromise |
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}.done { tokenType in |
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switch tokenType { |
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case .erc875: |
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self.storage.getERC875Balance(for: self.address) { result in |
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switch result { |
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case .success(let balance): |
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self.nonFungibleBalanceSeal.fulfill(balance) |
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self.completionOfPartialData(.balance(balance: balance, tokenType: .erc875)) |
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case .failure(let error): |
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self.nonFungibleBalanceSeal.reject(error) |
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self.callCompletionFailed() |
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} |
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} |
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case .erc721: |
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self.storage.getERC721Balance(for: self.address) { result in |
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switch result { |
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case .success(let balance): |
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self.nonFungibleBalanceSeal.fulfill(balance) |
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self.completionOfPartialData(.balance(balance: balance, tokenType: .erc721)) |
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case .failure(let error): |
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self.nonFungibleBalanceSeal.reject(error) |
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self.callCompletionFailed() |
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} |
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} |
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case .erc721ForTickets: |
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self.storage.getERC721ForTicketsBalance(for: self.address) { result in |
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switch result { |
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case .success(let balance): |
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self.nonFungibleBalanceSeal.fulfill(balance) |
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self.completionOfPartialData(.balance(balance: balance, tokenType: .erc721ForTickets)) |
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case .failure(let error): |
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self.nonFungibleBalanceSeal.reject(error) |
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self.callCompletionFailed() |
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} |
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} |
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case .erc20: |
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self.storage.getDecimals(for: self.address) { result in |
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switch result { |
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case .success(let decimal): |
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self.decimalsSeal.fulfill(decimal) |
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self.completionOfPartialData(.decimals(decimal)) |
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case .failure(let error): |
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self.decimalsSeal.reject(error) |
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self.callCompletionFailed() |
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} |
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} |
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case .nativeCryptocurrency: |
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break |
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} |
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}.cauterize() |
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} |
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private func completionOfPartialData(_ data: ContractData) -> Void { |
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completion?(data) |
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callCompletionOnAllData() |
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} |
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private func callCompletionFailed() { |
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guard !failed else { |
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return |
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} |
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failed = true |
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//TODO maybe better to share an instance of the reachability manager |
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completion?(.failed(networkReachable: NetworkReachabilityManager()?.isReachable)) |
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} |
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private func callCompletionAsDelegateTokenOrNot() { |
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assert(symbolPromise.value != nil && symbolPromise.value?.isEmpty == true) |
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//Must check because we also get an empty symbol (and name) if there's no connectivity |
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//TODO maybe better to share an instance of the reachability manager |
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if let reachabilityManager = NetworkReachabilityManager(), reachabilityManager.isReachable { |
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completion?(.delegateTokenComplete) |
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} else { |
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callCompletionFailed() |
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} |
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} |
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private func callCompletionOnAllData() { |
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if namePromise.isResolved, symbolPromise.isResolved, let tokenType = tokenTypePromise.value { |
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switch tokenType { |
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case .erc875, .erc721, .erc721ForTickets: |
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if let nonFungibleBalance = nonFungibleBalancePromise.value { |
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let name = namePromise.value |
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let symbol = symbolPromise.value |
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completion?(.nonFungibleTokenComplete(name: name ?? "", symbol: symbol ?? "", balance: nonFungibleBalance, tokenType: tokenType)) |
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} |
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case .nativeCryptocurrency, .erc20: |
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if let name = namePromise.value, let symbol = symbolPromise.value, let decimals = decimalsPromise.value { |
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if symbol.isEmpty { |
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callCompletionAsDelegateTokenOrNot() |
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} else { |
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completion?(.fungibleTokenComplete(name: name, symbol: symbol, decimals: decimals)) |
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} |
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} |
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} |
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} else if let name = namePromise.value, let symbol = symbolPromise.value, let decimals = decimalsPromise.value { |
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if symbol.isEmpty { |
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callCompletionAsDelegateTokenOrNot() |
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} else { |
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completion?(.fungibleTokenComplete(name: name, symbol: symbol, decimals: decimals)) |
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} |
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} |
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} |
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} |
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