fix: Add endpoints to VirtualFS

packages/cspell-io/src/VirtualFS.ts

@@ -4,15 +4,15 @@ import type { DirEntry, Disposable, FileReference, FileResource, Stats } from '.
 
 type UrlOrReference = URL | FileReference;
 
-type NextProvider = (url: URL) => FileSystem | undefined;
+type NextProvider = (url: URL) => ProviderFileSystem | undefined;
 
 export interface VirtualFS extends Disposable {
     registerFileSystemProvider(provider: FileSystemProvider): Disposable;
 
     /**
      * Get the fs for a given url.
      */
-    getFS(url: URL): FileSystem | undefined;
+    getFS(url: URL): FileSystem;
 
     /**
      * The file system. All requests will first use getFileSystem to get the file system before making the request.
@@ -25,29 +25,73 @@ export interface VirtualFS extends Disposable {
     reset(): void;
 }
 
-export interface FileSystem extends Disposable {
+export enum FSCapabilityFlags {
+    None = 0,
+    Stat = 1 << 0,
+    Read = 1 << 1,
+    Write = 1 << 2,
+    ReadWrite = Read | Write,
+    ReadDir = 1 << 3,
+    WriteDir = 1 << 4,
+    ReadWriteDir = ReadDir | WriteDir,
+}
+
+interface FileSystemProviderInfo {
+    name: string;
+}
+
+interface FileSystemBase {
     stat(url: UrlOrReference): Stats | Promise<Stats>;
     readFile(url: UrlOrReference): Promise<FileResource>;
-    readDirectory?(url: URL): Promise<DirEntry[]>;
+    readDirectory(url: URL): Promise<DirEntry[]>;
+    writeFile(file: FileResource): Promise<FileReference>;
+    /**
+     * Information about the provider.
+     * It is up to the provider to define what information is available.
+     */
+    providerInfo: FileSystemProviderInfo;
+}
+
+export interface FileSystem extends FileSystemBase {
+    getCapabilities(url: URL): FSCapabilities;
+    hasProvider: boolean;
+}
+
+export interface ProviderFileSystem extends FileSystemBase, Disposable {
+    /**
+     * These are the general capabilities for the provider's file system.
+     * It is possible for a provider to support more capabilities for a given url by providing a getCapabilities function.
+     */
+    capabilities: FSCapabilityFlags;
+
+    /**
+     * Get the capabilities for a URL. Make it possible for a provider to support more capabilities for a given url.
+     * These capabilities should be more restrictive than the general capabilities.
+     * @param url - the url to try
+     * @returns the capabilities for the url.
+     */
+    getCapabilities?: (url: URL) => FSCapabilities;
 }
 
 export interface FileSystemProvider extends Partial<Disposable> {
+    /** Name of the Provider */
+    name: string;
     /**
      * Get the file system for a given url. The provider is cached based upon the protocol and hostname.
      * @param url - the url to get the file system for.
      * @param next - call this function to get the next provider to try. This is useful for chaining providers that operate on the same protocol.
      */
-    getFileSystem(url: URL, next: NextProvider): FileSystem | undefined;
+    getFileSystem(url: URL, next: NextProvider): ProviderFileSystem | undefined;
 }
 
 class CVirtualFS implements VirtualFS {
     private readonly providers = new Set<FileSystemProvider>();
-    private cachedFs = new Map<string, FileSystem | undefined>();
+    private cachedFs = new Map<string, WrappedProviderFs>();
     private revCacheFs = new Map<FileSystemProvider, Set<string>>();
     readonly fs: Required<FileSystem>;
 
     constructor() {
-        this.fs = fsPassThrough((url) => this.getFS(url));
+        this.fs = fsPassThrough((url) => this._getFS(url));
     }
 
     registerFileSystemProvider(provider: FileSystemProvider): Disposable {
@@ -63,11 +107,16 @@ class CVirtualFS implements VirtualFS {
         };
     }
 
-    getFS(url: URL): FileSystem | undefined {
+    getFS(url: URL): FileSystem {
+        return this._getFS(url);
+    }
+
+    private _getFS(url: URL): WrappedProviderFs {
         const key = `${url.protocol}${url.hostname}`;
 
-        if (this.cachedFs.has(key)) {
-            return this.cachedFs.get(key);
+        const cached = this.cachedFs.get(key);
+        if (cached) {
+            return cached;
         }
 
         const fnNext = (provider: FileSystemProvider, next: NextProvider) => {
@@ -96,7 +145,7 @@ class CVirtualFS implements VirtualFS {
             next = fnNext(provider, next);
         }
 
-        const fs = next(url);
+        const fs = new WrappedProviderFs(next(url));
         this.cachedFs.set(key, fs);
         return fs;
     }
@@ -110,7 +159,7 @@ class CVirtualFS implements VirtualFS {
     private disposeOfCachedFs(): void {
         for (const [key, fs] of [...this.cachedFs].reverse()) {
             try {
-                fs?.dispose?.();
+                WrappedProviderFs.disposeOf(fs);
             } catch (e) {
                 // continue - we are cleaning up.
             }
@@ -132,26 +181,26 @@ class CVirtualFS implements VirtualFS {
     }
 }
 
-function fsPassThrough(fs: (url: URL) => FileSystem | undefined): Required<FileSystem> {
+function fsPassThrough(fs: (url: URL) => WrappedProviderFs): Required<FileSystem> {
     function gfs(ur: UrlOrReference, name: string): FileSystem {
         const url = urlOrReferenceToUrl(ur);
         const f = fs(url);
-        if (!f)
-            throw new VFSErrorUnhandledRequest(
+        if (!f.hasProvider)
+            throw new VFSErrorUnsupportedRequest(
                 name,
                 url,
                 ur instanceof URL ? undefined : { url: ur.url.toString(), encoding: ur.encoding },
             );
         return f;
     }
     return {
+        providerInfo: { name: 'default' },
+        hasProvider: true,
         stat: async (url) => gfs(url, 'stat').stat(url),
         readFile: async (url) => gfs(url, 'readFile').readFile(url),
-        readDirectory: async (url) => {
-            const fs = gfs(url, 'readDirectory');
-            return fs.readDirectory ? fs.readDirectory(url) : Promise.resolve([]);
-        },
-        dispose: () => undefined,
+        writeFile: async (file) => gfs(file, 'writeFile').writeFile(file),
+        readDirectory: async (url) => gfs(url, 'readDirectory').readDirectory(url),
+        getCapabilities: (url) => gfs(url, 'getCapabilities').getCapabilities(url),
     };
 }
 
@@ -167,15 +216,20 @@ export function createVirtualFS(cspellIO?: CSpellIO): VirtualFS {
 }
 
 function cspellIOToFsProvider(cspellIO: CSpellIO): FileSystemProvider {
+    const name = 'CSpellIO';
     const supportedProtocols = new Set(['file:', 'http:', 'https:']);
-    const fs: FileSystem = {
+    const fs: ProviderFileSystem = {
+        providerInfo: { name },
         stat: (url) => cspellIO.getStat(url),
         readFile: (url) => cspellIO.readFile(url),
         readDirectory: (url) => cspellIO.readDirectory(url),
+        writeFile: (file) => cspellIO.writeFile(file.url, file.content),
         dispose: () => undefined,
+        capabilities: FSCapabilityFlags.Stat | FSCapabilityFlags.ReadWrite | FSCapabilityFlags.ReadDir,
     };
 
     return {
+        name,
         getFileSystem: (url, _next) => {
             return supportedProtocols.has(url.protocol) ? fs : undefined;
         },
@@ -191,21 +245,147 @@ export function getDefaultVirtualFs(): VirtualFS {
     return defaultVirtualFs;
 }
 
+function wrapError(e: unknown): unknown {
+    if (e instanceof VFSError) return e;
+    // return new VFSError(e instanceof Error ? e.message : String(e), { cause: e });
+    return e;
+}
+
 export class VFSError extends Error {
-    constructor(message: string, options?: { cause?: Error }) {
+    constructor(message: string, options?: { cause?: unknown }) {
         super(message, options);
     }
 }
 
-export class VFSErrorUnhandledRequest extends VFSError {
+export class VFSErrorUnsupportedRequest extends VFSError {
     public readonly url?: string | undefined;
 
     constructor(
         public readonly request: string,
         url?: URL | string,
         public readonly parameters?: unknown,
     ) {
-        super(`Unhandled request: ${request}`);
+        super(`Unsupported request: ${request}`);
         this.url = url?.toString();
     }
 }
+
+export interface FSCapabilities {
+    readonly flags: FSCapabilityFlags;
+    readonly readFile: boolean;
+    readonly writeFile: boolean;
+    readonly readDirectory: boolean;
+    readonly writeDirectory: boolean;
+    readonly stat: boolean;
+}
+
+class CFsCapabilities {
+    constructor(readonly flags: FSCapabilityFlags) {}
+
+    get readFile(): boolean {
+        return !!(this.flags & FSCapabilityFlags.Read);
+    }
+
+    get writeFile(): boolean {
+        return !!(this.flags & FSCapabilityFlags.Write);
+    }
+
+    get readDirectory(): boolean {
+        return !!(this.flags & FSCapabilityFlags.ReadDir);
+    }
+
+    get writeDirectory(): boolean {
+        return !!(this.flags & FSCapabilityFlags.WriteDir);
+    }
+
+    get stat(): boolean {
+        return !!(this.flags & FSCapabilityFlags.Stat);
+    }
+}
+
+export function fsCapabilities(flags: FSCapabilityFlags): FSCapabilities {
+    return new CFsCapabilities(flags);
+}
+
+class WrappedProviderFs implements FileSystem {
+    readonly hasProvider: boolean;
+    readonly capabilities: FSCapabilityFlags;
+    readonly providerInfo: FileSystemProviderInfo;
+    private _capabilities: FSCapabilities;
+    constructor(private readonly fs: ProviderFileSystem | undefined) {
+        this.hasProvider = !!fs;
+        this.capabilities = fs?.capabilities || FSCapabilityFlags.None;
+        this._capabilities = fsCapabilities(this.capabilities);
+        this.providerInfo = fs?.providerInfo || { name: 'unknown' };
+    }
+
+    getCapabilities(url: URL): FSCapabilities {
+        if (this.fs?.getCapabilities) return this.fs.getCapabilities(url);
+
+        return this._capabilities;
+    }
+
+    async stat(url: UrlOrReference): Promise<Stats> {
+        try {
+            checkCapabilityOrThrow(
+                this.fs,
+                this.capabilities,
+                FSCapabilityFlags.Stat,
+                'stat',
+                urlOrReferenceToUrl(url),
+            );
+            return await this.fs.stat(url);
+        } catch (e) {
+            throw wrapError(e);
+        }
+    }
+
+    async readFile(url: UrlOrReference): Promise<FileResource> {
+        try {
+            checkCapabilityOrThrow(
+                this.fs,
+                this.capabilities,
+                FSCapabilityFlags.Read,
+                'readFile',
+                urlOrReferenceToUrl(url),
+            );
+            return await this.fs.readFile(url);
+        } catch (e) {
+            throw wrapError(e);
+        }
+    }
+
+    async readDirectory(url: URL): Promise<DirEntry[]> {
+        try {
+            checkCapabilityOrThrow(this.fs, this.capabilities, FSCapabilityFlags.ReadDir, 'readDirectory', url);
+            return await this.fs.readDirectory(url);
+        } catch (e) {
+            throw wrapError(e);
+        }
+    }
+
+    async writeFile(file: FileResource): Promise<FileReference> {
+        try {
+            checkCapabilityOrThrow(this.fs, this.capabilities, FSCapabilityFlags.Write, 'writeFile', file.url);
+            return await this.fs.writeFile(file);
+        } catch (e) {
+            throw wrapError(e);
+        }
+    }
+
+    static disposeOf(fs: FileSystem): void {
+        fs instanceof WrappedProviderFs && fs.fs?.dispose();
+    }
+}
+
+function checkCapabilityOrThrow(
+    fs: ProviderFileSystem | undefined,
+    capabilities: FSCapabilityFlags,
+    flag: FSCapabilityFlags,
+    name: string,
+    url: URL,
+): asserts fs is ProviderFileSystem {
+    if (!(capabilities & flag)) {
+        throw new VFSErrorUnsupportedRequest(name, url);
+    }
+}