Merge pull request #1316 from pacu/custom-checkpoint-provisioning

Create a Dependency that can load checkpoints from bundle

Sources/ZcashLightClientKit/Checkpoint/BundleCheckpointSource.swift

@@ -0,0 +1,38 @@
+//
+//  BundleCheckpointSource.swift
+//
+//
+//  Created by Francisco Gindre on 2023-10-30.
+//
+
+import Foundation
+
+struct BundleCheckpointSource: CheckpointSource {
+    var network: NetworkType
+
+    var saplingActivation: Checkpoint
+
+    init(network: NetworkType) {
+        self.network = network
+        self.saplingActivation = switch network {
+        case .mainnet:
+            Checkpoint.mainnetMin
+        case .testnet:
+            Checkpoint.testnetMin
+        }
+    }
+
+    func latestKnownCheckpoint() -> Checkpoint {
+        Checkpoint.birthday(
+            with: .max,
+            checkpointDirectory: BundleCheckpointURLProvider.default.url(self.network)
+        ) ?? saplingActivation
+    }
+
+    func birthday(for height: BlockHeight) -> Checkpoint {
+        Checkpoint.birthday(
+            with: height, 
+            checkpointDirectory: BundleCheckpointURLProvider.default.url(self.network)
+        ) ?? saplingActivation
+    }
+}

Sources/ZcashLightClientKit/Checkpoint/BundleCheckpointURLProvider.swift

@@ -0,0 +1,59 @@
+//
+//  BundleCheckpointURLProvider.swift
+//  
+//
+//  Created by Francisco Gindre on 2023-10-30.
+//
+
+import Foundation
+
+struct BundleCheckpointURLProvider {
+    var url: (NetworkType) -> URL
+}
+
+extension BundleCheckpointURLProvider {
+    /// Attempts to resolve the platform. `#if os(macOS)` implies that the build is for a macOS
+    /// target, otherwise we assume the build is for an iOS target.
+    static let `default` = BundleCheckpointURLProvider { networkType in
+        #if os(macOS)
+        Self.macOS.url(networkType)
+        #else
+        Self.iOS.url(networkType)
+        #endif
+    }
+
+    static let iOS = BundleCheckpointURLProvider(url: { networkType in
+        switch networkType {
+        case .mainnet:
+            return Checkpoint.mainnetCheckpointDirectory
+        case .testnet:
+            return Checkpoint.testnetCheckpointDirectory
+        }
+    })
+
+    /// This variant attempts to retrieve the saplingActivation checkpoint for the given network
+    /// type using `Bundle.module.url(forResource:withExtension:subdirectory:localization)`.
+    /// If not found it will return `WalletBirthday.mainnetCheckpointDirectory` or
+    /// `WalletBirthday.testnetCheckpointDirectory`. This responds to tests failing on a macOS
+    /// target because the checkpoint resources would not be found.
+    static let macOS = BundleCheckpointURLProvider(url: { networkType in
+        switch networkType {
+        case .mainnet:
+            return Bundle.module.url(
+                forResource: "419200",
+                withExtension: "json",
+                subdirectory: "checkpoints/mainnet/",
+                localization: nil
+            )?
+            .deletingLastPathComponent() ?? Checkpoint.mainnetCheckpointDirectory
+        case .testnet:
+            return Bundle.module.url(
+                forResource: "280000",
+                withExtension: "json",
+                subdirectory: "checkpoints/testnet/",
+                localization: nil
+            )?
+            .deletingLastPathComponent() ?? Checkpoint.testnetCheckpointDirectory
+        }
+    })
+}

Sources/ZcashLightClientKit/Constants/Checkpoint+Constants.swift → Sources/ZcashLightClientKit/Checkpoint/Checkpoint+helpers.swift

@@ -1,5 +1,5 @@
 //
-//  WalletBirthday+Constants.swift
+//  Checkpoint+helpers.swift
 //  ZcashLightClientKit
 //
 //  Created by Francisco Gindre on 7/28/21.
@@ -64,54 +64,3 @@ extension Checkpoint {
         }
     }
 }
-
-struct BundleCheckpointURLProvider {
-    var url: (NetworkType) -> URL
-}
-
-extension BundleCheckpointURLProvider {
-    /// Attempts to resolve the platform by checking `#if os(macOS)` build corresponds to a MacOS target
-    /// `#else` branch of that condition will assume iOS is the target platform
-    static let `default` = BundleCheckpointURLProvider { networkType in
-        #if os(macOS)
-        Self.macOS.url(networkType)
-        #else
-        Self.iOS.url(networkType)
-        #endif
-    }
-
-    static let iOS = BundleCheckpointURLProvider(url: { networkType in
-        switch networkType {
-        case .mainnet:
-            return Checkpoint.mainnetCheckpointDirectory
-        case .testnet:
-            return Checkpoint.testnetCheckpointDirectory
-        }
-    })
-
-    /// This variant attempts to retrieve the saplingActivation checkpoint for the given network type
-    /// using `Bundle.module.url(forResource:withExtension:subdirectory:localization)`
-    /// if not found it will return `WalletBirthday.mainnetCheckpointDirectory` or
-    /// `WalletBirthday.testnetCheckpointDirectory`. This responds to tests
-    /// failing on MacOS target because the checkpoint resources would fail.
-    static let macOS = BundleCheckpointURLProvider(url: { networkType in
-        switch networkType {
-        case .mainnet:
-            return Bundle.module.url(
-                forResource: "419200",
-                withExtension: "json",
-                subdirectory: "checkpoints/mainnet/",
-                localization: nil
-            )?
-            .deletingLastPathComponent() ?? Checkpoint.mainnetCheckpointDirectory
-        case .testnet:
-            return Bundle.module.url(
-                forResource: "280000",
-                withExtension: "json",
-                subdirectory: "checkpoints/testnet/",
-                localization: nil
-            )?
-            .deletingLastPathComponent() ?? Checkpoint.testnetCheckpointDirectory
-        }
-    })
-}

Sources/ZcashLightClientKit/Checkpoint/CheckpointSource.swift

@@ -0,0 +1,34 @@
+//
+//  CheckpointSource.swift
+//
+//
+//  Created by Francisco Gindre on 2023-10-30.
+//
+
+import Foundation
+
+/// A protocol that abstracts the requirements around obtaining wallet checkpoints
+/// (also known as TreeStates).
+protocol CheckpointSource {
+    /// `NetworkType` of this Checkpoint source
+    var network: NetworkType { get }
+
+    /// The `Checkpoint` that represents the block in which Sapling was activated
+    var saplingActivation: Checkpoint { get }
+
+    /// Obtain the latest `Checkpoint` in terms of block height known by
+    /// this `CheckpointSource`. It is possible that the returned checkpoint
+    /// is not the latest checkpoint that exists in the blockchain.
+    /// - Returns a `Checkpoint` with the highest height known by this source
+    func latestKnownCheckpoint() -> Checkpoint
+
+    /// Obtain a `Checkpoint` in terms of a "wallet birthday". Wallet birthday
+    /// is estimated to be the latest height of the Zcash blockchain at the moment when the wallet was
+    /// created.
+    /// - Parameter height: Estimated or effective height known for the wallet birthday
+    /// - Returns: a `Checkpoint` that will allow the wallet to manage funds from the given `height`
+    /// onwards.
+    /// - Note: When the user knows the exact height of the first received funds for a wallet,
+    /// the effective birthday of that wallet is `transaction.height - 1`.
+    func birthday(for height: BlockHeight) -> Checkpoint
+}

Sources/ZcashLightClientKit/Checkpoint/CheckpointSourceFactory.swift

@@ -0,0 +1,14 @@
+//
+//  CheckpointSourceFactory.swift
+//
+//
+//  Created by Francisco Gindre on 2023-10-30.
+//
+
+import Foundation
+
+struct CheckpointSourceFactory {
+    static func fromBundle(for network: NetworkType) -> CheckpointSource {
+        BundleCheckpointSource(network: network)
+    }
+}

Sources/ZcashLightClientKit/Initializer.swift

@@ -281,7 +281,7 @@ public class Initializer {
         self.storage = container.resolve(CompactBlockRepository.self)
         self.blockDownloaderService = container.resolve(BlockDownloaderService.self)
         self.network = network
-        self.walletBirthday = Checkpoint.birthday(with: 0, network: network).height
+        self.walletBirthday = container.resolve(CheckpointSource.self).saplingActivation.height
         self.urlsParsingError = urlsParsingError
         self.logger = container.resolve(Logger.self)
     }
@@ -416,7 +416,9 @@ public class Initializer {
             return .seedRequired
         }
 
-        let checkpoint = Checkpoint.birthday(with: walletBirthday, network: network)
+        let checkpointSource = container.resolve(CheckpointSource.self)
+
+        let checkpoint = checkpointSource.birthday(for: walletBirthday)
 
         self.walletBirthday = checkpoint.height
 

Sources/ZcashLightClientKit/Synchronizer/Dependencies.swift

@@ -17,6 +17,10 @@ enum Dependencies {
         loggingPolicy: Initializer.LoggingPolicy = .default(.debug),
         enableBackendTracing: Bool = false
     ) {
+        container.register(type: CheckpointSource.self, isSingleton: true) { _ in
+            return CheckpointSourceFactory.fromBundle(for: networkType)
+        }
+
         container.register(type: Logger.self, isSingleton: true) { _ in
             let logger: Logger
             switch loggingPolicy {

Tests/DarksideTests/ReOrgTests.swift

@@ -97,8 +97,9 @@ class ReOrgTests: ZcashTestCase {
         let mockLatestHeight = BlockHeight(663200)
         let targetLatestHeight = BlockHeight(663202)
         let reOrgHeight = BlockHeight(663195)
-        let walletBirthday = Checkpoint.birthday(with: 663150, network: network).height
-
+        let checkpointSource = CheckpointSourceFactory.fromBundle(for: network.networkType)
+        let walletBirthday = checkpointSource.birthday(for: 663150).height
+
         try await basicReOrgTest(
             baseDataset: .beforeReOrg,
             reorgDataset: .afterSmallReorg,
@@ -113,8 +114,9 @@ class ReOrgTests: ZcashTestCase {
         let mockLatestHeight = BlockHeight(663200)
         let targetLatestHeight = BlockHeight(663250)
         let reOrgHeight = BlockHeight(663180)
-        let walletBirthday = Checkpoint.birthday(with: BlockHeight(663150), network: network).height
-
+        let checkpointSource = CheckpointSourceFactory.fromBundle(for: network.networkType)
+        let walletBirthday = checkpointSource.birthday(for: 663150).height
+
         try await basicReOrgTest(
             baseDataset: .beforeReOrg,
             reorgDataset: .afterLargeReorg,

Tests/DarksideTests/TransactionEnhancementTests.swift

@@ -52,7 +52,8 @@ class TransactionEnhancementTests: ZcashTestCase {
 
         waitExpectation = XCTestExpectation(description: "\(self.description) waitExpectation")
 
-        let birthday = Checkpoint.birthday(with: walletBirthday, network: network)
+        let checkpointSource = CheckpointSourceFactory.fromBundle(for: network.networkType)
+        let birthday = checkpointSource.birthday(for: walletBirthday)
 
         let pathProvider = DefaultResourceProvider(network: network)
         processorConfig = CompactBlockProcessor.Configuration(