Refactor Node to support layout changes with backwad compatibility

src/filesystem/implementation.js

@@ -201,7 +201,7 @@ function find_node(context, path, callback) {
     } else if(!rootDirectoryNode) {
       callback(new Errors.ENOENT());
     } else {
-      callback(null, rootDirectoryNode);
+      Node.create(rootDirectoryNode, callback);
     }
   }
 
@@ -227,11 +227,18 @@ function find_node(context, path, callback) {
         callback(new Errors.ENOENT(null, path));
       } else {
         var nodeId = parentDirectoryData[name].id;
-        context.getObject(nodeId, is_symbolic_link);
+        context.getObject(nodeId, create_node);
       }
     }
   }
 
+  function create_node(error, data) {
+    if(error) {
+      return callback(error);
+    }
+    Node.create(data, is_symbolic_link);
+  }
+
   function is_symbolic_link(error, node) {
     if(error) {
       callback(error);
@@ -664,7 +671,7 @@ function open_file(context, path, flags, mode, callback) {
       fileNode = result;
       fileNode.nlinks += 1;
       if(mode){
-        Node.setMode(mode, fileNode);
+        fileNode.mode = mode;
       }
       context.putObject(fileNode.id, fileNode, write_file_data);
     });
@@ -2006,7 +2013,7 @@ function chmod_file(context, path, mode, callback) {
     if (error) {
       callback(error);
     } else {
-      Node.setMode(mode, node);
+      node.mode = mode;
       update_node_times(context, path, node, { mtime: Date.now() }, callback);
     }
   }

src/node.js

@@ -1,34 +1,60 @@
-var Constants = require('./constants.js');
-var NODE_TYPE_FILE = Constants.NODE_TYPE_FILE;
-var NODE_TYPE_DIRECTORY = Constants.NODE_TYPE_DIRECTORY;
-var NODE_TYPE_SYMBOLIC_LINK = Constants.NODE_TYPE_SYMBOLIC_LINK;
+const {
+  NODE_TYPE_FILE,
+  NODE_TYPE_DIRECTORY,
+  NODE_TYPE_SYMBOLIC_LINK,
+  DEFAULT_FILE_PERMISSIONS,
+  DEFAULT_DIR_PERMISSIONS
+} = require('./constants');
+const {
+  S_IFREG,
+  S_IFDIR,
+  S_IFLNK
+} = require('./constants').fsConstants;
 
-var S_IFREG = Constants.fsConstants.S_IFREG;
-var S_IFDIR = Constants.fsConstants.S_IFDIR;
-var S_IFLNK = Constants.fsConstants.S_IFLNK;
+/**
+ * Make sure the options object has an id on property,
+ * either from caller or one we generate using supplied guid fn.
+ */
+function ensureID(options, prop, callback) {
+  if(options[prop]) {
+    return callback();
+  }
 
-var DEFAULT_FILE_PERMISSIONS = Constants.DEFAULT_FILE_PERMISSIONS;
-var DEFAULT_DIR_PERMISSIONS = Constants.DEFAULT_DIR_PERMISSIONS;
+  options.guid(function(err, id) {
+    if(err) {
+      return callback(err);
+    }
+    options[prop] = id;
+    callback();
+  });
+}
 
-function getMode(type, mode) {
-  switch(type) {
+/**
+ * Generate a POSIX mode (integer) for the node type and permissions.
+ * Use default permissions if we aren't passed any.
+ */
+function generateMode(nodeType, modePermissions) {
+  switch(nodeType) {
   case NODE_TYPE_DIRECTORY:
-    return (mode || DEFAULT_DIR_PERMISSIONS) | S_IFDIR;
+    return (modePermissions || DEFAULT_DIR_PERMISSIONS) | S_IFDIR;
   case NODE_TYPE_SYMBOLIC_LINK:
-    return (mode || DEFAULT_FILE_PERMISSIONS) | S_IFLNK;
-    /* jshint -W086 */
+    return (modePermissions || DEFAULT_FILE_PERMISSIONS) | S_IFLNK;
   case NODE_TYPE_FILE:
     // falls through
   default:
-    return (mode || DEFAULT_FILE_PERMISSIONS) | S_IFREG;
+    return (modePermissions || DEFAULT_FILE_PERMISSIONS) | S_IFREG;
   }
 }
 
-function Node(options) {
+/**
+ * Common properties for the layout of a Node
+ */
+class Node {
+  constructor(options) {
     var now = Date.now();
 
     this.id = options.id;
-  this.type = options.type || NODE_TYPE_FILE;  // node type (file, directory, etc)
+    this.data = options.data; // id for data object
     this.size = options.size || 0; // size (bytes for files, entries for directories)
     this.atime = options.atime || now; // access time (will mirror ctime after creation)
     this.ctime = options.ctime || now; // creation/change time
@@ -36,50 +62,74 @@ function Node(options) {
     this.flags = options.flags || []; // file flags
     this.xattrs = options.xattrs || {}; // extended attributes
     this.nlinks = options.nlinks || 0; // links count
-  this.data = options.data; // id for data object
-  this.version = options.version || 1;
 
-  // permissions and flags
-  this.mode = options.mode || (getMode(this.type));
+    // Historically, Filer's node layout has referred to the
+    // node type as `mode`, and done so using a String.  In
+    // a POSIX filesystem, the mode is a number that combines
+    // both node type and permission bits. Internal we use `type`,
+    // but store it in the database as `mode` for backward
+    // compatibility.
+    if(typeof options.type === 'string') {
+      this.type = options.type;
+    } else if(typeof options.mode === 'string') {
+      this.type = options.mode;
+    } else {
+      this.type = NODE_TYPE_FILE;
+    }
+
+    // Extra mode permissions and ownership info
+    this.permissions = options.permissions || generateMode(this.type);
     this.uid = options.uid || 0x0; // owner name
     this.gid = options.gid || 0x0; // group name
-}
+  }
 
-// Make sure the options object has an id on property,
-// either from caller or one we generate using supplied guid fn.
-function ensureID(options, prop, callback) {
-  if(options[prop]) {
-    callback(null);
-  } else {
-    options.guid(function(err, id) {
-      options[prop] = id;
-      callback(err);
-    });
+  /**
+   * Serialize a Node to JSON.  Everything is as expected except
+   * that we use `mode` for `type` to maintain backward compatibility.
+   */
+  toJSON() {
+    return {
+      id: this.id,
+      data: this.data,
+      size: this.size,
+      atime: this.atime,
+      ctime: this.ctime,
+      mtime: this.ctime,
+      flags: this.flags,
+      xattrs: this.xattrs,
+      nlinks: this.nlinks,
+      // Use `mode` for `type` to keep backward compatibility
+      mode: this.type,
+      permissions: this.permissions,
+      uid: this.uid,
+      gid: this.gid
+    };
+  }
+
+  // Return complete POSIX `mode` for node type + permissions. See:
+  // http://man7.org/linux/man-pages/man2/chmod.2.html
+  get mode() {
+    return generateMode(this.type, this.permissions);
+  }
+  // When setting the `mode` we assume permissions bits only (not changing type)
+  set mode(value) {
+    this.permissions = value;
   }
 }
 
-Node.create = function(options, callback) {
+module.exports.create = function create(options, callback) {
   // We expect both options.id and options.data to be provided/generated.
   ensureID(options, 'id', function(err) {
     if(err) {
-      callback(err);
-      return;
+      return callback(err);
     }
 
     ensureID(options, 'data', function(err) {
       if(err) {
-        callback(err);
-        return;
+        return callback(err);
       }
 
       callback(null, new Node(options));
     });
   });
 };
-
-// Update the node's mode (permissions), taking file type bits into account.
-Node.setMode = function(mode, node) {
-  node.mode = getMode(node.type, mode);
-};
-
-module.exports = Node;

src/open-file-description.js

@@ -1,4 +1,5 @@
-var Errors = require('./errors.js');
+const Errors = require('./errors.js');
+const Node = require('./node');
 
 function OpenFileDescription(path, id, flags, position) {
   this.path = path;
@@ -22,7 +23,7 @@ OpenFileDescription.prototype.getNode = function(context, callback) {
       return callback(new Errors.EBADF('file descriptor refers to unknown node', path));
     }
 
-    callback(null, node);
+    Node.create(node, callback);
   }
 
   context.getObject(id, check_if_node_exists);