Implement renameAt.

lib/wasi-virt.js

@@ -149,7 +149,7 @@ class Directory {
     return Object.keys(this.files).length;
   }
 
-  traverse(path, flags = { create: false, remove: false }) {
+  traverse(path, { create = null, remove = false } = {}) {
     let entry = this;
     let separatorAt = -1;
     do {
@@ -158,18 +158,20 @@ class Directory {
       const files = entry.files;
       separatorAt = path.indexOf('/');
       const segment = separatorAt === -1 ? path : path.substring(0, separatorAt);
-      if (separatorAt === -1 && flags.remove)
+      if (separatorAt === -1 && remove)
         delete files[segment];
       else if (segment === '' || segment === '.')
         /* disregard */;
       else if (segment === '..')
         /* hack to make scandir() work */;
       else if (Object.hasOwn(files, segment))
         entry = files[segment];
-      else if (flags.create === 'directory' || flags.create === 'file' && separatorAt !== -1)
+      else if (create === 'directory' || (create !== null && separatorAt !== -1))
         entry = files[segment] = new Directory({});
-      else if (flags.create === 'file')
+      else if (create === 'file')
         entry = files[segment] = new File(new Uint8Array());
+      else if (create instanceof File || create instanceof Directory)
+        entry = files[segment] = create;
       else
         throw 'no-entry';
       path = path.substring(separatorAt + 1);
@@ -262,7 +264,7 @@ class Descriptor {
   openAt(_pathFlags, path, openFlags, _descriptorFlags) {
     if (!(this.entry instanceof Directory))
       throw 'invalid';
-    const openEntry = this.entry.traverse(path, { create: openFlags.create ? 'file' : false });
+    const openEntry = this.entry.traverse(path, openFlags.create ? { create: 'file' } : {});
     if (openFlags.directory) {
       if (!(openEntry instanceof Directory))
         throw 'not-directory';
@@ -323,6 +325,16 @@ class Descriptor {
     const _pathEntry = this.entry.traverse(path);
     throw 'invalid';
   }
+
+  renameAt(oldPath, newDescriptor, newPath) {
+    if (!(this.entry instanceof Directory))
+      throw 'not-directory';
+    if (!(newDescriptor.entry instanceof Directory))
+      throw 'not-directory';
+    const oldEntry = this.entry.traverse(oldPath);
+    this.entry.traverse(newPath, { create: oldEntry });
+    this.entry.traverse(oldPath, { remove: true });
+  }
 }
 
 class DirectoryEntryStream {