add option to specify default constant value for scale storage

novasamatech · Mar 1, 2022 · e561cf4 · e561cf4
1 parent caf3e00
commit e561cf4
Show file tree

Hide file tree

Showing 3 changed files with 72 additions and 12 deletions.
diff --git a/novawallet/Common/Operation/StorageDecodingOperation.swift b/novawallet/Common/Operation/StorageDecodingOperation.swift
@@ -235,8 +235,11 @@ final class StorageConstantOperation<T: Decodable>: BaseOperation<T>, ConstantDe
 
     let path: ConstantCodingPath
 
-    init(path: ConstantCodingPath) {
+    let fallbackValue: T?
+
+    init(path: ConstantCodingPath, fallbackValue: T? = nil) {
         self.path = path
+        self.fallbackValue = fallbackValue
 
         super.init()
     }
@@ -260,7 +263,14 @@ final class StorageConstantOperation<T: Decodable>: BaseOperation<T>, ConstantDe
             let item: T = try decode(at: path, codingFactory: factory).map(to: T.self)
             result = .success(item)
         } catch {
-            result = .failure(error)
+            if
+                let storageError = error as? StorageDecodingOperationError,
+                storageError == .invalidStoragePath,
+                let fallbackValue = fallbackValue {
+                result = .success(fallbackValue)
+            } else {
+                result = .failure(error)
+            }
         }
     }
 }
@@ -270,8 +280,11 @@ final class PrimitiveConstantOperation<T: LosslessStringConvertible & Equatable>
 
     let path: ConstantCodingPath
 
-    init(path: ConstantCodingPath) {
+    let fallbackValue: T?
+
+    init(path: ConstantCodingPath, fallbackValue: T? = nil) {
         self.path = path
+        self.fallbackValue = fallbackValue
 
         super.init()
     }
@@ -296,7 +309,14 @@ final class PrimitiveConstantOperation<T: LosslessStringConvertible & Equatable>
                 .map(to: StringScaleMapper<T>.self)
             result = .success(item.value)
         } catch {
-            result = .failure(error)
+            if
+                let storageError = error as? StorageDecodingOperationError,
+                storageError == .invalidStoragePath,
+                let fallbackValue = fallbackValue {
+                result = .success(fallbackValue)
+            } else {
+                result = .failure(error)
+            }
         }
     }
 }
diff --git a/novawallet/Common/Protocols/RuntimeConstantFetching.swift b/novawallet/Common/Protocols/RuntimeConstantFetching.swift
@@ -6,13 +6,15 @@ protocol RuntimeConstantFetching {
         for path: ConstantCodingPath,
         runtimeCodingService: RuntimeCodingServiceProtocol,
         operationManager: OperationManagerProtocol,
+        fallbackValue: T?,
         closure: @escaping (Result<T, Error>) -> Void
     ) -> CancellableCall
 
     func fetchCompoundConstant<T: Decodable>(
         for path: ConstantCodingPath,
         runtimeCodingService: RuntimeCodingServiceProtocol,
         operationManager: OperationManagerProtocol,
+        fallbackValue: T?,
         closure: @escaping (Result<T, Error>) -> Void
     ) -> CancellableCall
 }
@@ -24,9 +26,42 @@ extension RuntimeConstantFetching {
         runtimeCodingService: RuntimeCodingServiceProtocol,
         operationManager: OperationManagerProtocol,
         closure: @escaping (Result<T, Error>) -> Void
+    ) -> CancellableCall {
+        fetchConstant(
+            for: path,
+            runtimeCodingService: runtimeCodingService,
+            operationManager: operationManager,
+            fallbackValue: nil,
+            closure: closure
+        )
+    }
+
+    @discardableResult
+    func fetchCompoundConstant<T: Decodable>(
+        for path: ConstantCodingPath,
+        runtimeCodingService: RuntimeCodingServiceProtocol,
+        operationManager: OperationManagerProtocol,
+        closure: @escaping (Result<T, Error>) -> Void
+    ) -> CancellableCall {
+        fetchCompoundConstant(
+            for: path,
+            runtimeCodingService: runtimeCodingService,
+            operationManager: operationManager,
+            fallbackValue: nil,
+            closure: closure
+        )
+    }
+
+    @discardableResult
+    func fetchConstant<T: LosslessStringConvertible & Equatable>(
+        for path: ConstantCodingPath,
+        runtimeCodingService: RuntimeCodingServiceProtocol,
+        operationManager: OperationManagerProtocol,
+        fallbackValue: T?,
+        closure: @escaping (Result<T, Error>) -> Void
     ) -> CancellableCall {
         let codingFactoryOperation = runtimeCodingService.fetchCoderFactoryOperation()
-        let constOperation = PrimitiveConstantOperation<T>(path: path)
+        let constOperation = PrimitiveConstantOperation<T>(path: path, fallbackValue: fallbackValue)
         constOperation.configurationBlock = {
             do {
                 constOperation.codingFactory = try codingFactoryOperation.extractNoCancellableResultData()
@@ -57,10 +92,11 @@ extension RuntimeConstantFetching {
         for path: ConstantCodingPath,
         runtimeCodingService: RuntimeCodingServiceProtocol,
         operationManager: OperationManagerProtocol,
+        fallbackValue: T?,
         closure: @escaping (Result<T, Error>) -> Void
     ) -> CancellableCall {
         let codingFactoryOperation = runtimeCodingService.fetchCoderFactoryOperation()
-        let constOperation = StorageConstantOperation<T>(path: path)
+        let constOperation = StorageConstantOperation<T>(path: path, fallbackValue: fallbackValue)
         constOperation.configurationBlock = {
             do {
                 constOperation.codingFactory = try codingFactoryOperation.extractNoCancellableResultData()

diff --git a/.../Staking/SelectValidatorsFlow/SelectValidatorsStart/SelectValidatorsStartInteractor.swift b/.../Staking/SelectValidatorsFlow/SelectValidatorsStart/SelectValidatorsStartInteractor.swift
@@ -36,18 +36,22 @@ final class SelectValidatorsStartInteractor: RuntimeConstantFetching {
 
         operationManager.enqueue(operations: wrapper.allOperations, in: .transient)
     }
-}
-
-extension SelectValidatorsStartInteractor: SelectValidatorsStartInteractorInputProtocol {
-    func setup() {
-        prepareRecommendedValidatorList()
 
+    private func provideMaxNominations() {
         fetchConstant(
             for: .maxNominations,
             runtimeCodingService: runtimeService,
-            operationManager: operationManager
+            operationManager: operationManager,
+            fallbackValue: SubstrateConstants.maxNominations
         ) { [weak self] (result: Result<Int, Error>) in
             self?.presenter.didReceiveMaxNominations(result: result)
         }
     }
 }
+
+extension SelectValidatorsStartInteractor: SelectValidatorsStartInteractorInputProtocol {
+    func setup() {
+        prepareRecommendedValidatorList()
+        provideMaxNominations()
+    }
+}