feat: .zoid-meta virtual file

packages/fuse-client/syscalls/flush.ts

@@ -6,6 +6,10 @@ export const flush: (backend: SQLiteBackend) => MountOptions["flush"] = (
 ) => {
   return async (path, fd, cb) => {
     console.info("flush(%s, %d)", path, fd);
+    if (backend.isVirtualFile(path)) {
+      cb(0);
+      return;
+    }
     await backend.flush(path);
     cb(0);
   };

packages/fuse-client/syscalls/getattr.ts

@@ -7,6 +7,13 @@ export const getattr: (backend: SQLiteBackend) => MountOptions["getattr"] = (
 ) => {
   return async (path, cb) => {
     console.info("getattr(%s)", path);
+
+    if (backend.isVirtualFile(path)) {
+      const virtualFile = backend.getVirtualFile(path);
+      cb(0, virtualFile.getAttr());
+      return;
+    }
+
     const r = await backend.getFile(path);
     await match(r)
       .with({ status: "ok" }, async (r) => {

packages/fuse-client/syscalls/open.ts

@@ -7,8 +7,14 @@ export const open: (backend: SQLiteBackend) => MountOptions["open"] = (
 ) => {
   return async (path, flags, cb) => {
     console.info("open(%s, %d)", path, flags);
-    const r = await backend.getFile(path);
 
+    if (backend.isVirtualFile(path)) {
+      const virtualFile = backend.getVirtualFile(path);
+      cb(0, virtualFile.fileId);
+      return;
+    }
+
+    const r = await backend.getFile(path);
     match(r)
       .with({ status: "ok" }, (r) => {
         cb(0, r.file.id);

packages/fuse-client/syscalls/read.ts

@@ -7,6 +7,15 @@ export const read: (backend: SQLiteBackend) => MountOptions["read"] = (
 ) => {
   return async (path, fd, buf, len, pos, cb) => {
     console.info("read(%s, %d, %d, %d)", path, fd, len, pos);
+
+    if (backend.isVirtualFile(path)) {
+      const virtualFile = backend.getVirtualFile(path);
+      const bufChunk = virtualFile.getBuffer();
+      buf.write(bufChunk.toString("binary"), "binary");
+      cb(Buffer.byteLength(bufChunk));
+      return;
+    }
+
     const r = await backend.getFileChunks(fd, pos, len);
     await match(r)
       .with({ status: "ok" }, async (r) => {

packages/fuse-client/syscalls/readdir.ts

@@ -7,11 +7,13 @@ export const readdir: (backend: SQLiteBackend) => MountOptions["readdir"] = (
   return async (path, cb) => {
     console.info("readdir(%s)", path);
 
-    // TODO: figure out how are these directories in output of ls -la
     const dotDirs = [".", ".."];
-
+    const metaFiles: string[] = backend.getVirtualFilePaths(path);
     const links = await backend.getLinks(path);
-    const fileNames = dotDirs.concat(links.map((link) => link.name));
+    const fileNames = dotDirs
+      // Note: trim the first / of /.zoid-meta returning .zoid-meta
+      .concat(metaFiles.map((metaFile) => metaFile.slice(1)))
+      .concat(links.map((link) => link.name));
 
     return cb(0, fileNames);
   };

packages/sqlite-backend/SQLiteBackend.ts

@@ -6,6 +6,8 @@ import { rawCreateMany } from "./prismaRawUtil";
 import { WriteBuffer } from "./WriteBuffer";
 import mmmagic, { Magic } from "mmmagic";
 import { promisify } from "util";
+import { VirtualFiles } from "./VirtualFiles";
+import { VirtualFile } from "./VirtualFile";
 
 export type ContentChunk = {
   content: Buffer;
@@ -19,6 +21,7 @@ export class SQLiteBackend implements Backend {
   private readonly writeBuffers: Map<string, WriteBuffer<ContentChunk>> =
     new Map();
   private readonly prisma: PrismaClient;
+  private readonly virtualFiles: VirtualFiles;
   constructor(prismaOrDbUrl?: PrismaClient | string) {
     if (prismaOrDbUrl instanceof PrismaClient) {
       this.prisma = prismaOrDbUrl;
@@ -35,6 +38,33 @@ export class SQLiteBackend implements Backend {
 
       this.prisma.$connect();
     }
+
+    const virtualFile = new VirtualFile(
+      999,
+      "/.zoid-meta",
+      JSON.stringify(
+        {
+          databaseUrl: process.env.DATABASE_URL,
+        },
+        null,
+        2
+      ) + "\n"
+    );
+    const virtualFileMap = new Map();
+    virtualFileMap.set(virtualFile.path, virtualFile);
+    this.virtualFiles = new VirtualFiles(virtualFileMap);
+  }
+
+  isVirtualFile(filepath: string) {
+    return this.virtualFiles.isVirtualFile(filepath);
+  }
+
+  getVirtualFile(filepath: string) {
+    return this.virtualFiles.getVirtualFile(filepath)!;
+  }
+
+  getVirtualFilePaths(filepath: string) {
+    return this.virtualFiles.filePaths(filepath);
   }
 
   async write(filepath: string, chunk: ContentChunk) {

packages/sqlite-backend/VirtualFile.ts

@@ -0,0 +1,39 @@
+export class VirtualFile {
+  private _date = new Date();
+  constructor(
+    private _fileId: number,
+    private _path: string,
+    private _content: string
+  ) {}
+
+  get path() {
+    return this._path;
+  }
+
+  get fileId() {
+    return this._fileId;
+  }
+
+  getBuffer() {
+    return Buffer.from(this._content);
+  }
+
+  getSize() {
+    return Buffer.byteLength(this.getBuffer());
+  }
+
+  getAttr() {
+    return {
+      mtime: this._date,
+      atime: this._date,
+      ctime: this._date,
+      blocks: 1,
+      ino: this.fileId,
+      nlink: 1,
+      size: this.getSize(),
+      mode: 33188,
+      uid: process.getuid ? process.getuid() : 0,
+      gid: process.getgid ? process.getgid() : 0,
+    };
+  }
+}

packages/sqlite-backend/VirtualFiles.ts

@@ -0,0 +1,21 @@
+import { VirtualFile } from "./VirtualFile";
+
+export class VirtualFiles {
+  constructor(private _files: Map<string, VirtualFile>) {}
+
+  filePaths(path: string) {
+    if (path === "/") {
+      return Array.from(this._files.keys());
+    }
+    return [];
+  }
+
+  isVirtualFile(path: string) {
+    // TODO: find correct directory
+    return this._files.has(path);
+  }
+
+  getVirtualFile(path: string) {
+    return this._files.get(path);
+  }
+}