Merge pull request #1015 from aciidb0mb3r/reloadable-result

[Workspace] Make managed dependencies reloadable

Author: aciidgh

Sources/Workspace/Workspace.swift

@@ -229,7 +229,7 @@ public class Workspace {
     private let containerProvider: RepositoryPackageContainerProvider
 
     /// The current state of managed dependencies.
-    let managedDependencies: ManagedDependencies
+    let managedDependencies: ReloadableResult<ManagedDependencies, AnyError>
 
     /// Enable prefetching containers in resolver.
     let enableResolverPrefetching: Bool
@@ -278,7 +278,9 @@ public class Workspace {
         self.fileSystem = fileSystem
 
         self.pinsStore = try PinsStore(pinsFile: pinsFile, fileSystem: self.fileSystem)
-        self.managedDependencies = try ManagedDependencies(dataPath: dataPath, fileSystem: fileSystem)
+        self.managedDependencies = ReloadableResult{
+            try ManagedDependencies(dataPath: dataPath, fileSystem: fileSystem)
+        }
 
         // Ensure the cache path exists.
         try createCacheDirectories()
@@ -314,7 +316,7 @@ public class Workspace {
         let protectedAssets = Set<String>([
             repositoryManager.path,
             checkoutsPath,
-            managedDependencies.statePath,
+            try managedDependencies.dematerialize().statePath,
         ].map { path in
             // Assert that these are present inside data directory.
             assert(path.parentDirectory == dataPath)
@@ -332,7 +334,7 @@ public class Workspace {
 
     /// Resets the entire workspace by removing the data directory.
     public func reset() throws {
-        managedDependencies.reset()
+        try managedDependencies.dematerialize().reset()
         repositoryManager.reset()
         fileSystem.removeFileTree(dataPath)
         try createCacheDirectories()
@@ -433,6 +435,7 @@ public class Workspace {
                     relative: false)
         }
 
+        let managedDependencies = try self.managedDependencies.dematerialize()
         // Change its stated to edited.
         managedDependencies[dependency.repository] = dependency.makingEditable(
             subpath: RelativePath(packageName), state: state)
@@ -484,6 +487,7 @@ public class Workspace {
         if fileSystem.exists(editablesPath), try fileSystem.getDirectoryContents(editablesPath).isEmpty {
             fileSystem.removeFileTree(editablesPath)
         }
+        let managedDependencies = try self.managedDependencies.dematerialize()
         // Restore the dependency state.
         managedDependencies[dependency.repository] = dependency.basedOn
         // Save the state.
@@ -545,6 +549,7 @@ public class Workspace {
         try updateCheckouts(with: results)
 
         // Get the updated dependency.
+        let managedDependencies = try self.managedDependencies.dematerialize()
         let newDependency = managedDependencies[dependency.repository]!
 
         // Assert that the dependency is at the pinned checkout state now.
@@ -615,6 +620,7 @@ public class Workspace {
     /// - Returns: The path of the local repository.
     /// - Throws: If the operation could not be satisfied.
     private func fetch(repository: RepositorySpecifier) throws -> AbsolutePath {
+        let managedDependencies = try self.managedDependencies.dematerialize()
         // If we already have it, fetch to update the repo from its remote.
         if let dependency = managedDependencies[repository] {
             let path = checkoutsPath.appending(dependency.subpath)
@@ -666,6 +672,7 @@ public class Workspace {
         try workingRepo.checkout(revision: checkoutState.revision)
 
         // Write the state record.
+        let managedDependencies = try self.managedDependencies.dematerialize()
         managedDependencies[repository] = ManagedDependency(
                 repository: repository, subpath: path.relative(to: checkoutsPath),
                 checkoutState: checkoutState)
@@ -757,6 +764,7 @@ public class Workspace {
             return try pinAll(reset: true)
         }
 
+        let managedDependencies = try self.managedDependencies.dematerialize()
         // Otherwise, we need to repin only the previous pins.
         for pin in pinsStore.pins {
             // Check if this is a stray pin.
@@ -810,6 +818,7 @@ public class Workspace {
         updateBranches: Bool
     ) throws -> [RepositorySpecifier: PackageStateChange] {
         var packageStateChanges = [RepositorySpecifier: PackageStateChange]()
+        let managedDependencies = try self.managedDependencies.dematerialize()
         // Set the states from resolved dependencies results.
         for (specifier, binding) in resolvedDependencies {
             switch binding {
@@ -895,7 +904,10 @@ public class Workspace {
     /// This will load the manifests for the root package as well as all the
     /// current dependencies from the working checkouts.
     public func loadDependencyManifests(_ rootManifests: [Manifest]) -> DependencyManifests {
-
+        guard let managedDependencies = try? self.managedDependencies.dematerialize() else {
+            // We need to capture the error here and continue.
+            fatalError("unimplemented.")
+        }
         // Compute the transitive closure of available dependencies.
         let dependencies = transitiveClosure(rootManifests.map{ KeyedPair($0, key: $0.url) }) { node in
             return node.item.package.dependencies.flatMap{ dependency in
@@ -950,6 +962,7 @@ public class Workspace {
     /// If some edited dependency is removed from the file system, mark it as unedited and
     /// fallback on the original checkout.
     private func validateEditedPackages() throws {
+        let managedDependencies = try self.managedDependencies.dematerialize()
         for dependency in managedDependencies.values {
 
             let dependencyPath: AbsolutePath
@@ -1055,6 +1068,7 @@ public class Workspace {
 
     /// Removes the clone and checkout of the provided specifier.
     func remove(specifier: RepositorySpecifier) throws {
+        let managedDependencies = try self.managedDependencies.dematerialize()
         guard var dependency = managedDependencies[specifier] else {
             fatalError("This should never happen, trying to remove \(specifier) which isn't in workspace")
         }
@@ -1152,3 +1166,30 @@ extension Collection {
         return (result, errors)
     }
 }
+
+/// A result which can be reloaded.
+///
+/// It is useful for objects that holds a state on disk and needs to be
+/// reloaded frequently.
+final class ReloadableResult<Value, ErrorType: Swift.Error> {
+
+    /// The constructor closure for the value.
+    private let construct: () throws -> Value
+
+    /// Create a reloadable result.
+    init(_ construct: @escaping () throws -> Value) {
+        self.construct = construct
+    }
+
+    /// Load and return the result.
+    func result() -> Result<Value, ErrorType> {
+        return try! Result {
+            try self.construct()
+        }
+    }
+
+    /// Load and return the value.
+    func dematerialize() throws -> Value {
+        return try result().dematerialize()
+    }
+}

Tests/WorkspaceTests/WorkspaceTests.swift

@@ -89,7 +89,7 @@ extension Workspace {
     }
 
     func getDependency(for url: AbsolutePath) -> ManagedDependency {
-        return managedDependencies[url.asString]!
+        return try! managedDependencies.dematerialize()[url.asString]!
     }
 }
 
@@ -125,7 +125,7 @@ final class WorkspaceTests: XCTestCase {
             // Create the initial workspace.
             do {
                 let workspace = try Workspace.createWith(rootPackage: path)
-                XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository.url }, [])
+                XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository.url }, [])
 
                 // Do a low-level clone.
                 let state = CheckoutState(revision: currentRevision)
@@ -136,8 +136,8 @@ final class WorkspaceTests: XCTestCase {
             // Re-open the workspace, and check we know the checkout version.
             do {
                 let workspace = try Workspace.createWith(rootPackage: path)
-                XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository }, [testRepoSpec])
-                if let dependency = workspace.managedDependencies.values.first(where: { _ in true }) {
+                XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository }, [testRepoSpec])
+                if let dependency = try workspace.managedDependencies.dematerialize().values.first(where: { _ in true }) {
                     XCTAssertEqual(dependency.repository, testRepoSpec)
                     XCTAssertEqual(dependency.checkoutState?.revision, currentRevision)
                 }
@@ -152,9 +152,9 @@ final class WorkspaceTests: XCTestCase {
             let statePath: AbsolutePath
             do {
                 let workspace = try Workspace.createWith(rootPackage: path)
-                statePath = workspace.managedDependencies.statePath
-                XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository }, [testRepoSpec])
-                if let dependency = workspace.managedDependencies.values.first(where: { _ in true }) {
+                statePath = try workspace.managedDependencies.dematerialize().statePath
+                XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository }, [testRepoSpec])
+                if let dependency = try workspace.managedDependencies.dematerialize().values.first(where: { _ in true }) {
                     XCTAssertEqual(dependency.repository, testRepoSpec)
                     XCTAssertEqual(dependency.checkoutState?.revision, initialRevision)
                 }
@@ -164,10 +164,10 @@ final class WorkspaceTests: XCTestCase {
             try removeFileTree(statePath)
             do {
                 let workspace = try Workspace.createWith(rootPackage: path)
-                XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository.url }, [])
+                XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository.url }, [])
                 let state = CheckoutState(revision: currentRevision)
                 _ = try workspace.clone(repository: testRepoSpec, at: state)
-                XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository }, [testRepoSpec])
+                XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository }, [testRepoSpec])
             }
         }
     }
@@ -430,7 +430,7 @@ final class WorkspaceTests: XCTestCase {
             let workspace = try Workspace.createWith(rootPackage: path)
             let state = CheckoutState(revision: Revision(identifier: "initial"))
             let checkoutPath = try workspace.clone(repository: testRepoSpec, at: state)
-            XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository }, [testRepoSpec])
+            XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository }, [testRepoSpec])
 
             // Drop a build artifact in data directory.
             let buildArtifact = workspace.dataPath.appending(component: "test.o")
@@ -442,7 +442,7 @@ final class WorkspaceTests: XCTestCase {
 
             try workspace.clean()
 
-            XCTAssertEqual(workspace.managedDependencies.values.map{ $0.repository }, [testRepoSpec])
+            XCTAssertEqual(try workspace.managedDependencies.dematerialize().values.map{ $0.repository }, [testRepoSpec])
             XCTAssert(localFileSystem.exists(workspace.dataPath))
             // The checkout should be safe.
             XCTAssert(localFileSystem.exists(checkoutPath))
@@ -458,7 +458,7 @@ final class WorkspaceTests: XCTestCase {
             XCTAssertFalse(localFileSystem.exists(buildArtifact))
             XCTAssertFalse(localFileSystem.exists(checkoutPath))
             XCTAssertTrue(localFileSystem.exists(workspace.dataPath))
-            XCTAssertTrue(workspace.managedDependencies.values.map{$0}.isEmpty)
+            XCTAssertTrue(try workspace.managedDependencies.dematerialize().values.map{$0}.isEmpty)
         }
     }
 
@@ -488,7 +488,7 @@ final class WorkspaceTests: XCTestCase {
             }
 
             func getDependency(_ manifest: Manifest) -> ManagedDependency {
-                return workspace.managedDependencies[manifest.url]!
+                return try! workspace.managedDependencies.dematerialize()[manifest.url]!
             }
 
             // Get the dependency for package A.
@@ -525,7 +525,7 @@ final class WorkspaceTests: XCTestCase {
             do {
                 // Reopen workspace and check if we maintained the state.
                 let workspace = try Workspace.createWith(rootPackage: path, manifestLoader: manifestGraph.manifestLoader, delegate: TestWorkspaceDelegate())
-                let dependency = workspace.managedDependencies[RepositorySpecifier(url: aManifest.url)]!
+                let dependency = try workspace.managedDependencies.dematerialize()[RepositorySpecifier(url: aManifest.url)]!
                 XCTAssert(dependency.state == .edited)
             }
 
@@ -558,7 +558,7 @@ final class WorkspaceTests: XCTestCase {
                 return XCTFail("Expected manifest for package A not found")
             }
             func getDependency(_ manifest: Manifest) -> ManagedDependency {
-                return workspace.managedDependencies[manifest.url]!
+                return try! workspace.managedDependencies.dematerialize()[manifest.url]!
             }
             // Get the dependency for package A.
             let dependency = getDependency(aManifest)
@@ -614,7 +614,7 @@ final class WorkspaceTests: XCTestCase {
                 return XCTFail("Expected manifest for package A not found")
             }
             func getDependency(_ manifest: Manifest) -> ManagedDependency {
-                return workspace.managedDependencies[manifest.url]!
+                return try! workspace.managedDependencies.dematerialize()[manifest.url]!
             }
             let dependency = getDependency(aManifest)
             // Put the dependency in edit mode.
@@ -1163,7 +1163,7 @@ final class WorkspaceTests: XCTestCase {
             XCTAssertTrue(g.errors.isEmpty)
             XCTAssert(g.lookup("A").version == "1.0.1")
             // FIXME: We also cloned B because it has a pin.
-            XCTAssertNotNil(workspace.managedDependencies[manifestGraph.repo("B")])
+            XCTAssertNotNil(try workspace.managedDependencies.dematerialize()[manifestGraph.repo("B")])
         }
 
         do {
@@ -1175,7 +1175,7 @@ final class WorkspaceTests: XCTestCase {
             XCTAssertTrue(g.errors.isEmpty)
             XCTAssert(g.lookup("A").version == "1.0.1")
             // This dependency should be removed on updating dependencies because it is not referenced anywhere.
-            XCTAssertNil(workspace.managedDependencies[manifestGraph.repo("B")])
+            XCTAssertNil(try workspace.managedDependencies.dematerialize()[manifestGraph.repo("B")])
         }
     }
 
@@ -1483,7 +1483,7 @@ final class WorkspaceTests: XCTestCase {
 
             // Put A in edit mode.
             let aManifest = try workspace.loadDependencyManifests().lookup(manifest: "A")!
-            let dependency = workspace.managedDependencies[RepositorySpecifier(url: aManifest.url)]!
+            let dependency = try workspace.managedDependencies.dematerialize()[RepositorySpecifier(url: aManifest.url)]!
             try workspace.edit(dependency: dependency, packageName: aManifest.name, revision: dependency.checkoutState!.revision)
 
             // We should retain the original pin for a package which is in edit mode.
@@ -1674,7 +1674,7 @@ final class WorkspaceTests: XCTestCase {
                 rootPackage: path, manifestLoader: manifestGraph.manifestLoader, delegate: TestWorkspaceDelegate())
 
             func getDependency(_ manifest: Manifest) -> ManagedDependency {
-                return workspace.managedDependencies[manifest.url]!
+                return try! workspace.managedDependencies.dematerialize()[manifest.url]!
             }
 
             // Load the package graph.