Editor Restoration (#2078)

### Description

Implements editor restoration, helping ease the user experience for longer editing tasks spanning multiple files. Users expect opened tabs to retain the scroll position, cursors, and undo stack. To facilitate this, we receive a stream of state updates from the editor and save them to a SQLite DB. When a file is opened again, the state is restored from that DB.

Ideally this is transparent to the user. However, there is one very slight UX flaw that this doesn't address: highlighting. When a user restores an editor there can be a flash as the highlighter works to do syntax highlighting on the newly opened editor. Some potential future directions:
- The text storage object that outlives editors does retain color information, if we could avoid wiping that color information when an editor is loaded we could avoid that slight delay.
- To do that, we need to store that state with the storage object somehow. Either through a custom text attribute (could be finicky) or maybe by subclassing NSTextStorage and adding a flag.

> [!NOTE]
> This includes a mechanism for sharing undo stacks for editors during a workspace's lifetime. As @austincondiff mentioned on discord, it should add a undo frame when a file is updated externally. This PR notably does not include that change. I'll be adding it in #2075 

### Related Issues

* closes #2057 

### Checklist

- [x] I read and understood the [contributing guide](https://github.com/CodeEditApp/CodeEdit/blob/main/CONTRIBUTING.md) as well as the [code of conduct](https://github.com/CodeEditApp/CodeEdit/blob/main/CODE_OF_CONDUCT.md)
- [x] The issues this PR addresses are related to each other
- [x] My changes generate no new warnings
- [x] My code builds and runs on my machine
- [x] My changes are all related to the related issue above
- [x] I documented my code

### Screenshots


https://github.com/user-attachments/assets/6a9ff5ea-743e-4183-83c9-b774915b0c35

Author: thecoolwinter

CodeEdit.xcodeproj/project.pbxproj

@@ -21,12 +21,14 @@
 		6C0617D62BDB4432008C9C42 /* LogStream in Frameworks */ = {isa = PBXBuildFile; productRef = 6C0617D52BDB4432008C9C42 /* LogStream */; };
 		6C0824A12C5C0C9700A0751E /* SwiftTerm in Frameworks */ = {isa = PBXBuildFile; productRef = 6C0824A02C5C0C9700A0751E /* SwiftTerm */; };
 		6C147C4529A329350089B630 /* OrderedCollections in Frameworks */ = {isa = PBXBuildFile; productRef = 6C147C4429A329350089B630 /* OrderedCollections */; };
+		6C315FC82E05E33D0011BFC5 /* CodeEditSourceEditor in Frameworks */ = {isa = PBXBuildFile; productRef = 6C315FC72E05E33D0011BFC5 /* CodeEditSourceEditor */; };
 		6C4E37FC2C73E00700AEE7B5 /* SwiftTerm in Frameworks */ = {isa = PBXBuildFile; productRef = 6C4E37FB2C73E00700AEE7B5 /* SwiftTerm */; };
 		6C66C31329D05CDC00DE9ED2 /* GRDB in Frameworks */ = {isa = PBXBuildFile; productRef = 6C66C31229D05CDC00DE9ED2 /* GRDB */; };
 		6C6BD6F429CD142C00235D17 /* CollectionConcurrencyKit in Frameworks */ = {isa = PBXBuildFile; productRef = 6C6BD6F329CD142C00235D17 /* CollectionConcurrencyKit */; };
 		6C6BD6F829CD14D100235D17 /* CodeEditKit in Frameworks */ = {isa = PBXBuildFile; productRef = 6C6BD6F729CD14D100235D17 /* CodeEditKit */; };
 		6C6BD6F929CD14D100235D17 /* CodeEditKit in Embed Frameworks */ = {isa = PBXBuildFile; productRef = 6C6BD6F729CD14D100235D17 /* CodeEditKit */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 		6C73A6D32D4F1E550012D95C /* CodeEditSourceEditor in Frameworks */ = {isa = PBXBuildFile; productRef = 6C73A6D22D4F1E550012D95C /* CodeEditSourceEditor */; };
+		6C76D6D42E15B91E00EF52C3 /* CodeEditSourceEditor in Frameworks */ = {isa = PBXBuildFile; productRef = 6C76D6D32E15B91E00EF52C3 /* CodeEditSourceEditor */; };
 		6C81916B29B41DD300B75C92 /* DequeModule in Frameworks */ = {isa = PBXBuildFile; productRef = 6C81916A29B41DD300B75C92 /* DequeModule */; };
 		6C85BB402C2105ED00EB5DEF /* CodeEditKit in Frameworks */ = {isa = PBXBuildFile; productRef = 6C85BB3F2C2105ED00EB5DEF /* CodeEditKit */; };
 		6C85BB442C210EFD00EB5DEF /* SwiftUIIntrospect in Frameworks */ = {isa = PBXBuildFile; productRef = 6C85BB432C210EFD00EB5DEF /* SwiftUIIntrospect */; };
@@ -170,6 +172,8 @@
 				58F2EB1E292FB954004A9BDE /* Sparkle in Frameworks */,
 				6C147C4529A329350089B630 /* OrderedCollections in Frameworks */,
 				6CE21E872C650D2C0031B056 /* SwiftTerm in Frameworks */,
+				6C76D6D42E15B91E00EF52C3 /* CodeEditSourceEditor in Frameworks */,
+				6C315FC82E05E33D0011BFC5 /* CodeEditSourceEditor in Frameworks */,
 				6CC00A8B2CBEF150004E8134 /* CodeEditSourceEditor in Frameworks */,
 				6CD3CA552C8B508200D83DCD /* CodeEditSourceEditor in Frameworks */,
 				6C0617D62BDB4432008C9C42 /* LogStream in Frameworks */,
@@ -323,6 +327,8 @@
 				6C73A6D22D4F1E550012D95C /* CodeEditSourceEditor */,
 				5EACE6212DF4BF08005E08B8 /* WelcomeWindow */,
 				5E4485602DF600D9008BBE69 /* AboutWindow */,
+				6C315FC72E05E33D0011BFC5 /* CodeEditSourceEditor */,
+				6C76D6D32E15B91E00EF52C3 /* CodeEditSourceEditor */,
 			);
 			productName = CodeEdit;
 			productReference = B658FB2C27DA9E0F00EA4DBD /* CodeEdit.app */;
@@ -425,9 +431,9 @@
 				303E88462C276FD600EEA8D9 /* XCRemoteSwiftPackageReference "LanguageServerProtocol" */,
 				6C4E37FA2C73E00700AEE7B5 /* XCRemoteSwiftPackageReference "SwiftTerm" */,
 				6CB94D012CA1205100E8651C /* XCRemoteSwiftPackageReference "swift-async-algorithms" */,
-				6CF368562DBBD274006A77FD /* XCRemoteSwiftPackageReference "CodeEditSourceEditor" */,
 				5EACE6202DF4BF08005E08B8 /* XCRemoteSwiftPackageReference "WelcomeWindow" */,
 				5E44855F2DF600D9008BBE69 /* XCRemoteSwiftPackageReference "AboutWindow" */,
+				6C76D6D22E15B91E00EF52C3 /* XCRemoteSwiftPackageReference "CodeEditSourceEditor" */,
 			);
 			preferredProjectObjectVersion = 55;
 			productRefGroup = B658FB2D27DA9E0F00EA4DBD /* Products */;
@@ -1755,6 +1761,14 @@
 				minimumVersion = 0.2.0;
 			};
 		};
+		6C76D6D22E15B91E00EF52C3 /* XCRemoteSwiftPackageReference "CodeEditSourceEditor" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/CodeEditApp/CodeEditSourceEditor";
+			requirement = {
+				kind = exactVersion;
+				version = 0.14.1;
+			};
+		};
 		6C85BB3E2C2105ED00EB5DEF /* XCRemoteSwiftPackageReference "CodeEditKit" */ = {
 			isa = XCRemoteSwiftPackageReference;
 			repositoryURL = "https://github.com/CodeEditApp/CodeEditKit";
@@ -1779,14 +1793,6 @@
 				version = 1.0.1;
 			};
 		};
-		6CF368562DBBD274006A77FD /* XCRemoteSwiftPackageReference "CodeEditSourceEditor" */ = {
-			isa = XCRemoteSwiftPackageReference;
-			repositoryURL = "https://github.com/CodeEditApp/CodeEditSourceEditor";
-			requirement = {
-				kind = exactVersion;
-				version = 0.14.1;
-			};
-		};
 /* End XCRemoteSwiftPackageReference section */
 
 /* Begin XCSwiftPackageProductDependency section */
@@ -1839,6 +1845,10 @@
 			package = 6C147C4329A329350089B630 /* XCRemoteSwiftPackageReference "swift-collections" */;
 			productName = OrderedCollections;
 		};
+		6C315FC72E05E33D0011BFC5 /* CodeEditSourceEditor */ = {
+			isa = XCSwiftPackageProductDependency;
+			productName = CodeEditSourceEditor;
+		};
 		6C4E37FB2C73E00700AEE7B5 /* SwiftTerm */ = {
 			isa = XCSwiftPackageProductDependency;
 			package = 6C4E37FA2C73E00700AEE7B5 /* XCRemoteSwiftPackageReference "SwiftTerm" */;
@@ -1862,6 +1872,11 @@
 			isa = XCSwiftPackageProductDependency;
 			productName = CodeEditSourceEditor;
 		};
+		6C76D6D32E15B91E00EF52C3 /* CodeEditSourceEditor */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = 6C76D6D22E15B91E00EF52C3 /* XCRemoteSwiftPackageReference "CodeEditSourceEditor" */;
+			productName = CodeEditSourceEditor;
+		};
 		6C7B1C752A1D57CE005CBBFC /* SwiftLint */ = {
 			isa = XCSwiftPackageProductDependency;
 			package = 287136B1292A407E00E9F5F4 /* XCRemoteSwiftPackageReference "SwiftLintPlugin" */;

CodeEdit.xcodeproj/project.xcworkspace/xcshareddata/swiftpm/Package.resolved

@@ -76,6 +76,7 @@ final class CodeEditSplitViewController: NSSplitViewController {
                     .environmentObject(statusBarViewModel)
                     .environmentObject(utilityAreaModel)
                     .environmentObject(taskManager)
+                    .environmentObject(workspace.undoRegistration)
             }
         }
 

CodeEdit/Features/Documents/Controllers/CodeEditSplitViewController.swift

@@ -29,6 +29,7 @@ extension WorkspaceDocument {
         @Published var searchResultsCount: Int = 0
         /// Stores the user's input, shown when no files are found, and persists across navigation items.
         @Published var searchQuery: String = ""
+        @Published var replaceText: String = ""
 
         @Published var indexStatus: IndexStatus = .none
 

CodeEdit/Features/Documents/WorkspaceDocument/WorkspaceDocument+SearchState.swift

@@ -45,6 +45,8 @@ final class WorkspaceDocument: NSDocument, ObservableObject, NSToolbarDelegate {
     var workspaceSettingsManager: CEWorkspaceSettings?
     var taskNotificationHandler: TaskNotificationHandler = TaskNotificationHandler()
 
+    var undoRegistration: UndoManagerRegistration = UndoManagerRegistration()
+
     @Published var notificationPanel = NotificationPanelViewModel()
     private var cancellables = Set<AnyCancellable>()
 

CodeEdit/Features/Documents/WorkspaceDocument/WorkspaceDocument.swift

@@ -55,34 +55,40 @@ final class Editor: ObservableObject, Identifiable {
     var id = UUID()
 
     weak var parent: SplitViewData?
+    weak var workspace: WorkspaceDocument?
 
     init() {
         self.tabs = []
         self.temporaryTab = nil
         self.parent = nil
+        self.workspace = nil
     }
 
     init(
         files: OrderedSet<CEWorkspaceFile> = [],
         selectedTab: Tab? = nil,
         temporaryTab: Tab? = nil,
-        parent: SplitViewData? = nil
+        parent: SplitViewData? = nil,
+        workspace: WorkspaceDocument? = nil,
     ) {
         self.tabs = []
         self.parent = parent
+        self.workspace = workspace
         files.forEach { openTab(file: $0) }
-        self.selectedTab = selectedTab ?? (files.isEmpty ? nil : Tab(file: files.first!))
+        self.selectedTab = selectedTab ?? (files.isEmpty ? nil : Tab(workspace: workspace, file: files.first!))
         self.temporaryTab = temporaryTab
     }
 
     init(
         files: OrderedSet<Tab> = [],
         selectedTab: Tab? = nil,
         temporaryTab: Tab? = nil,
-        parent: SplitViewData? = nil
+        parent: SplitViewData? = nil,
+        workspace: WorkspaceDocument? = nil
     ) {
         self.tabs = []
         self.parent = parent
+        self.workspace = workspace
         files.forEach { openTab(file: $0.file) }
         self.selectedTab = selectedTab ?? tabs.first
         self.temporaryTab = temporaryTab
@@ -135,7 +141,7 @@ final class Editor: ObservableObject, Identifiable {
             clearFuture()
         }
         if file != selectedTab?.file {
-            addToHistory(EditorInstance(file: file))
+            addToHistory(EditorInstance(workspace: workspace, file: file))
         }
         removeTab(file)
         if let selectedTab {
@@ -165,7 +171,7 @@ final class Editor: ObservableObject, Identifiable {
     ///   - file: the file to open.
     ///   - asTemporary: indicates whether the tab should be opened as a temporary tab or a permanent tab.
     func openTab(file: CEWorkspaceFile, asTemporary: Bool) {
-        let item = EditorInstance(file: file)
+        let item = EditorInstance(workspace: workspace, file: file)
         // Item is already opened in a tab.
         guard !tabs.contains(item) || !asTemporary else {
             selectedTab = item
@@ -207,7 +213,7 @@ final class Editor: ObservableObject, Identifiable {
     ///   - index: Index where the tab needs to be added. If nil, it is added to the back.
     ///   - fromHistory: Indicates whether the tab has been opened from going back in history.
     func openTab(file: CEWorkspaceFile, at index: Int? = nil, fromHistory: Bool = false) {
-        let item = Tab(file: file)
+        let item = Tab(workspace: workspace, file: file)
         if let index {
             tabs.insert(item, at: index)
         } else {

CodeEdit/Features/Editor/Models/Editor+History.swift renamed to CodeEdit/Features/Editor/Models/Editor/Editor+History.swift

@@ -13,33 +13,105 @@ import CodeEditSourceEditor
 
 /// A single instance of an editor in a group with a published ``EditorInstance/cursorPositions`` variable to publish
 /// the user's current location in a file.
-class EditorInstance: Hashable {
-    // Public
-
+class EditorInstance: ObservableObject, Hashable {
     /// The file presented in this editor instance.
     let file: CEWorkspaceFile
 
     /// A publisher for the user's current location in a file.
-    var cursorPositions: AnyPublisher<[CursorPosition], Never> {
-        cursorSubject.eraseToAnyPublisher()
-    }
+    @Published var cursorPositions: [CursorPosition]
+    @Published var scrollPosition: CGPoint?
 
-    // Public TextViewCoordinator APIs
+    @Published var findText: String?
+    var findTextSubject: PassthroughSubject<String?, Never>
 
-    var rangeTranslator: RangeTranslator?
+    @Published var replaceText: String?
+    var replaceTextSubject: PassthroughSubject<String?, Never>
 
-    // Internal Combine subjects
+    var rangeTranslator: RangeTranslator = RangeTranslator()
 
-    private let cursorSubject = CurrentValueSubject<[CursorPosition], Never>([])
+    private var cancellables: Set<AnyCancellable> = []
 
-    // MARK: - Init, Hashable, Equatable
+    // MARK: - Init
 
-    init(file: CEWorkspaceFile, cursorPositions: [CursorPosition] = []) {
+    init(workspace: WorkspaceDocument?, file: CEWorkspaceFile, cursorPositions: [CursorPosition]? = nil) {
         self.file = file
-        self.cursorSubject.send(cursorPositions)
-        self.rangeTranslator = RangeTranslator(cursorSubject: cursorSubject)
+        let url = file.url
+        let editorState = EditorStateRestoration.shared?.restorationState(for: url)
+
+        findText = workspace?.searchState?.searchQuery
+        findTextSubject = PassthroughSubject()
+        replaceText = workspace?.searchState?.replaceText
+        replaceTextSubject = PassthroughSubject()
+
+        self.cursorPositions = (
+            cursorPositions ?? editorState?.editorCursorPositions ?? [CursorPosition(line: 1, column: 1)]
+        )
+        self.scrollPosition = editorState?.scrollPosition
+
+        // Setup listeners
+
+        Publishers.CombineLatest(
+            $cursorPositions.removeDuplicates(),
+            $scrollPosition
+                .debounce(for: .seconds(0.1), scheduler: RunLoop.main) // This can trigger *very* often
+                .removeDuplicates()
+        )
+        .sink { (cursorPositions, scrollPosition) in
+            EditorStateRestoration.shared?.updateRestorationState(
+                for: url,
+                data: .init(cursorPositions: cursorPositions, scrollPosition: scrollPosition ?? .zero)
+            )
+        }
+        .store(in: &cancellables)
+
+        listenToFindText(workspace: workspace)
+        listenToReplaceText(workspace: workspace)
+    }
+
+    // MARK: - Find/Replace Listeners
+
+    func listenToFindText(workspace: WorkspaceDocument?) {
+        workspace?.searchState?.$searchQuery
+            .receive(on: RunLoop.main)
+            .sink { [weak self] newQuery in
+                if self?.findText != newQuery {
+                    self?.findText = newQuery
+                }
+            }
+            .store(in: &cancellables)
+        findTextSubject
+            .receive(on: RunLoop.main)
+            .sink { [weak workspace, weak self] newFindText in
+                if let newFindText, workspace?.searchState?.searchQuery != newFindText {
+                    workspace?.searchState?.searchQuery = newFindText
+                }
+                self?.findText = workspace?.searchState?.searchQuery
+            }
+            .store(in: &cancellables)
+    }
+
+    func listenToReplaceText(workspace: WorkspaceDocument?) {
+        workspace?.searchState?.$replaceText
+            .receive(on: RunLoop.main)
+            .sink { [weak self] newText in
+                if self?.replaceText != newText {
+                    self?.replaceText = newText
+                }
+            }
+            .store(in: &cancellables)
+        replaceTextSubject
+            .receive(on: RunLoop.main)
+            .sink { [weak workspace, weak self] newReplaceText in
+                if let newReplaceText, workspace?.searchState?.replaceText != newReplaceText {
+                    workspace?.searchState?.replaceText = newReplaceText
+                }
+                self?.replaceText = workspace?.searchState?.replaceText
+            }
+            .store(in: &cancellables)
     }
 
+    // MARK: - Hashable, Equatable
+
     func hash(into hasher: inout Hasher) {
         hasher.combine(file)
     }
@@ -53,19 +125,17 @@ class EditorInstance: Hashable {
     /// Translates ranges (eg: from a cursor position) to other information like the number of lines in a range.
     class RangeTranslator: TextViewCoordinator {
         private weak var textViewController: TextViewController?
-        private var cursorSubject: CurrentValueSubject<[CursorPosition], Never>
-
-        init(cursorSubject: CurrentValueSubject<[CursorPosition], Never>) {
-            self.cursorSubject = cursorSubject
-        }
 
-        func textViewDidChangeSelection(controller: TextViewController, newPositions: [CursorPosition]) {
-            self.cursorSubject.send(controller.cursorPositions)
-        }
+        init() { }
 
         func prepareCoordinator(controller: TextViewController) {
             self.textViewController = controller
-            self.cursorSubject.send(controller.cursorPositions)
+        }
+
+        func controllerDidAppear(controller: TextViewController) {
+            if controller.isEditable && controller.isSelectable {
+                controller.view.window?.makeFirstResponder(controller.textView)
+            }
         }
 
         func destroy() {