add javascript example

example/provider/javascript/js/filesystem.js

@@ -0,0 +1,104 @@
+
+import { BaseFileSystem, ERRNO, Mode, AccessMode, OpenFlags } from "./webfuse/webfuse.js"
+
+class FileSystem extends BaseFileSystem {
+
+    constructor(tokenProvider, stateListener, files) {
+        super();
+
+        this.tokenProvider = tokenProvider;
+        this.stateListener = stateListener
+        this.files = new Map();
+        for(const file of files) {
+            this.files.set("/" + file.name, file);
+        }
+    }
+
+    access(path, mode) {
+        // we do not allow write or execute
+        if ((mode & AccessMode.W_OK) || (mode & AccessMode.X_OK)) {
+            return ERRNO.EACCES;
+        }
+
+        if ((path = "/") || (this.files.has(path))) {
+            return 0;
+        }
+
+        return ERRNO.ENOENT;
+    }
+
+    getattr(path) {
+        if (path == "/") {
+            return {
+                nlink: 2,
+                mode: Mode.DIR | 0o555
+            };
+        }
+        else if (this.files.has(path)) {
+            const file = this.files.get(path);
+            const contents = file.contents();
+            return {
+                nlink: 1,
+                mode: Mode.REG | 0o444,
+                size: contents.length
+            };
+        }
+
+        return ERRNO.ENOENT;
+    }
+
+    readdir(path) {
+        if (path == "/") {
+            const list = [];
+            for(const file of this.files.values()) {
+                list.push(file.name);
+            }
+            return list;
+        }
+        
+        return ERRNO.ENOENT;
+    }
+
+    open(path, flags) {
+        if (this.files.has(path)) {
+            const accessMode = flags & OpenFlags.ACCESS_MODE;
+            if (accessMode == OpenFlags.RDONLY) {
+                return [0, 0];
+            }
+            else {
+                return [ERRNO.EPERM, 0];
+            }
+        }
+
+        return [ERRNO.ENOENT, 0];
+    }
+
+    read(path, size, offset, fd) {
+        if (this.files.has(path)) {
+            const file = this.files.get(path);
+            const contents = file.contents();
+            if (offset < contents.length) {
+                const available = contents.length - offset;
+                const length = (size < available) ? size : available;
+                const data = contents.slice(offset, offset + length);
+                return data;
+            }
+
+            return [];
+        }
+        else {
+            return ERRNO.EBADF;
+        }
+    }
+
+    getcreds() {
+        const token = this.tokenProvider();
+        return token;
+    }
+
+    connectionstatechanged(state) {
+        this.stateListener(state);
+    }    
+}
+
+export { FileSystem }