[Workspace] Move PinsStore to use SimplePersistence

Sources/Utility/SimplePersistence.swift

@@ -36,14 +36,19 @@ public final class SimplePersistence {
     /// The path at which we persist the state.
     private let statePath: AbsolutePath
 
+    /// Writes the state files with pretty print JSON.
+    private let prettyPrint: Bool
+
     public init(
         fileSystem: FileSystem,
         schemaVersion: Int,
-        statePath: AbsolutePath
+        statePath: AbsolutePath,
+        prettyPrint: Bool = false
     ) {
         self.fileSystem = fileSystem
         self.schemaVersion = schemaVersion
         self.statePath = statePath
+        self.prettyPrint = prettyPrint
     }
 
     public func restoreState(_ object: SimplePersistanceProtocol) throws -> Bool {
@@ -69,6 +74,7 @@ public final class SimplePersistence {
             "object": object
         ])
         // FIXME: This should write atomically.
-        try fileSystem.writeFileContents(statePath, bytes: data.toBytes())
+        try fileSystem.writeFileContents(
+            statePath, bytes: data.toBytes(prettyPrint: self.prettyPrint))
     }
 }

Sources/Workspace/PinsStore.swift

@@ -9,7 +9,7 @@
 */
 
 import Basic
-import struct Utility.Version
+import Utility
 import SourceControl
 import typealias PackageGraph.RepositoryPackageConstraint
 
@@ -18,7 +18,7 @@ public enum PinOperationError: Swift.Error {
     case autoPinEnabled
 }
 
-public struct PinsStore {
+public final class PinsStore {
     public struct Pin {
         /// The package name of the pinned dependency.
         public let package: String
@@ -62,6 +62,8 @@ public struct PinsStore {
         return AnySequence<Pin>(pinsMap.values)
     }
 
+    fileprivate let persistence: SimplePersistence
+
     /// Create a new pins store.
     ///
     /// - Parameters:
@@ -70,13 +72,18 @@ public struct PinsStore {
     public init(pinsFile: AbsolutePath, fileSystem: FileSystem) throws {
         self.pinsFile = pinsFile
         self.fileSystem = fileSystem
+        self.persistence = SimplePersistence(
+            fileSystem: fileSystem,
+            schemaVersion: 1,
+            statePath: pinsFile,
+            prettyPrint: true)
         pinsMap = [:]
         autoPin = true
-        try restoreState()
+        _ = try self.persistence.restoreState(self)
     }
 
     /// Update the autopin setting. Writes the setting to pins file.
-    public mutating func setAutoPin(on value: Bool) throws {
+    public func setAutoPin(on value: Bool) throws {
         autoPin = value
         try saveState()
     }
@@ -90,7 +97,7 @@ public struct PinsStore {
     ///   - state: The state to pin at.
     ///   - reason: The reason for pinning.
     /// - Throws: PinOperationError
-    public mutating func pin(
+    public func pin(
         package: String,
         repository: RepositorySpecifier,
         state: CheckoutState,
@@ -113,7 +120,7 @@ public struct PinsStore {
     /// - Returns: The pin which was removed.
     /// - Throws: PinOperationError
     @discardableResult
-    public mutating func unpin(package: String) throws -> Pin {
+    public func unpin(package: String) throws -> Pin {
         // Ensure autopin is not on.
         guard !autoPin else {
             throw PinOperationError.autoPinEnabled
@@ -127,7 +134,7 @@ public struct PinsStore {
     }
 
     /// Unpin all of the currently pinnned dependencies.
-    public mutating func unpinAll() throws {
+    public func unpinAll() throws {
         // Reset the pins map.
         pinsMap = [:]
         // Save the state.
@@ -144,45 +151,23 @@ public struct PinsStore {
 }
 
 /// Persistence.
-extension PinsStore {
-    // FIXME: A lot of the persistence mechanism here is copied from
-    // `RepositoryManager`. It would be nice to get actual infrastructure around
-    // persistence to handle the boilerplate parts.
-
-    private enum PersistenceError: Swift.Error {
-        /// There was a missing or malformed key.
-        case unexpectedData
-    }
+extension PinsStore: SimplePersistanceProtocol {
 
-    /// The current schema version for the persisted information.
-    private static let currentSchemaVersion = 1
+    fileprivate func saveState() throws {
+        try self.persistence.saveState(self)
+    }
 
-    fileprivate mutating func restoreState() throws {
-        if !fileSystem.exists(pinsFile) {
-            return
-        }
-        // Load the state.
-        let json = try JSON(bytes: try fileSystem.readFileContents(pinsFile))
-
-        // Load the state from JSON.
-        // FIXME: We will need migration support when we update pins schema.
-        guard try json.get("version") == PinsStore.currentSchemaVersion else {
-            fatalError("Migration not supported yet")
-        }
-        // Load the pins.
+    public func restore(from json: JSON) throws {
         self.autoPin = try json.get("autoPin")
         self.pinsMap = try Dictionary(items: json.get("pins").map{($0.package, $0)})
     }
 
     /// Saves the current state of pins.
-    fileprivate mutating func saveState() throws {
-        let data = JSON([
-            "version": PinsStore.currentSchemaVersion,
+    public func toJSON() -> JSON {
+        return JSON([
             "pins": pins.sorted{$0.package < $1.package}.toJSON(),
             "autoPin": autoPin,
         ])
-        // FIXME: This should write atomically.
-        try fileSystem.writeFileContents(pinsFile, bytes: data.toBytes(prettyPrint: true))
     }
 }
 

Tests/CommandsTests/PackageToolTests.swift

@@ -18,7 +18,7 @@ import SourceControl
 import TestSupport
 import Utility
 import Workspace
-@testable import struct Workspace.PinsStore
+@testable import class Workspace.PinsStore
 
 final class PackageToolTests: XCTestCase {
     private func execute(_ args: [String], chdir: AbsolutePath? = nil) throws -> String {

Tests/WorkspaceTests/PinsStoreTests.swift

@@ -11,7 +11,7 @@
 import XCTest
 
 import Basic
-import struct Utility.Version
+import Utility
 import TestSupport
 import SourceControl
 @testable import Workspace
@@ -34,7 +34,7 @@ final class PinsStoreTests: XCTestCase {
 
         let fs = InMemoryFileSystem()
         let pinsFile = AbsolutePath("/pinsfile.txt")
-        var store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
+        let store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
         // Pins file should not be created right now.
         XCTAssert(!fs.exists(pinsFile))
         XCTAssert(store.pins.map{$0}.isEmpty)
@@ -45,13 +45,13 @@ final class PinsStoreTests: XCTestCase {
 
         // Test autopin toggle and persistence.
         do {
-            var store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
+            let store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
             XCTAssert(store.autoPin)
             try store.setAutoPin(on: false)
             XCTAssertFalse(store.autoPin)
         }
         do {
-            var store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
+            let store = try PinsStore(pinsFile: pinsFile, fileSystem: fs)
             XCTAssertFalse(store.autoPin)
             try store.setAutoPin(on: true)
             XCTAssert(store.autoPin)