Simplify syncing logic

frontend/sync-client/src/utils/debugging/in-memory-file-system.ts

@@ -0,0 +1,69 @@
+import type { RelativePath } from "../../persistence/database";
+import type { TextWithCursors } from "reconcile-text";
+import type { FileSystemOperations } from "../../file-operations/filesystem-operations";
+
+export class InMemoryFileSystem implements FileSystemOperations {
+    protected readonly files = new Map<string, Uint8Array>();
+
+    public async listFilesRecursively(
+        _root: RelativePath | undefined = undefined // we don't use multi-level paths during tests
+    ): Promise<RelativePath[]> {
+        return Array.from(this.files.keys());
+    }
+
+    public async read(path: RelativePath): Promise<Uint8Array> {
+        const file = this.files.get(path);
+        if (!file) {
+            throw new Error(`File ${path} does not exist`);
+        }
+        return file;
+    }
+
+    public async write(path: RelativePath, content: Uint8Array): Promise<void> {
+        this.files.set(path, content);
+    }
+
+    public async atomicUpdateText(
+        path: RelativePath,
+        updater: (current: TextWithCursors) => TextWithCursors
+    ): Promise<string> {
+        const file = this.files.get(path);
+        if (!file) {
+            throw new Error(`File ${path} does not exist`);
+        }
+        const currentContent = new TextDecoder().decode(file);
+        const newContent = updater({ text: currentContent, cursors: [] }).text;
+        this.files.set(path, new TextEncoder().encode(newContent));
+        return newContent;
+    }
+
+    public async getFileSize(path: RelativePath): Promise<number> {
+        return (await this.read(path)).length;
+    }
+
+    public async exists(path: RelativePath): Promise<boolean> {
+        return this.files.has(path);
+    }
+
+    public async createDirectory(_path: RelativePath): Promise<void> {
+        // This doesn't mean anything in our virtual FS representation
+    }
+
+    public async delete(path: RelativePath): Promise<void> {
+        this.files.delete(path);
+    }
+
+    public async rename(
+        oldPath: RelativePath,
+        newPath: RelativePath
+    ): Promise<void> {
+        const file = this.files.get(oldPath);
+        if (!file) {
+            throw new Error(`File ${oldPath} does not exist`);
+        }
+        this.files.set(newPath, file);
+        if (oldPath !== newPath) {
+            this.files.delete(oldPath);
+        }
+    }
+}