From 37ffdd59462a5201a346bdf23852fa4532c5e15d Mon Sep 17 00:00:00 2001
From: Volker Mische <volker.mische@gmail.com>
Date: Wed, 17 Jul 2019 17:59:02 +0200
Subject: [PATCH] perf: remove manual enumerability modifications

Instead of changing the enumerability of certain fields, just generate
the appropriate output of the `tree()` call. This is possible in dag-pb
as there are no user-defined dynamic fields that we might be able to
resolve into.

Closes #152.
---
 src/dag-link/dagLink.js |  5 ----
 src/dag-node/dagNode.js |  5 ----
 src/resolver.js         | 23 +++++++-----------
 src/visibility.js       | 53 -----------------------------------------
 4 files changed, 9 insertions(+), 77 deletions(-)
 delete mode 100644 src/visibility.js

diff --git a/src/dag-link/dagLink.js b/src/dag-link/dagLink.js
index f10d82c..82f4ef0 100644
--- a/src/dag-link/dagLink.js
+++ b/src/dag-link/dagLink.js
@@ -2,7 +2,6 @@
 
 const CID = require('cids')
 const assert = require('assert')
-const visibility = require('../visibility')
 const withIs = require('class-is')
 
 // Link represents an IPFS Merkle DAG Link between Nodes.
@@ -17,10 +16,6 @@ class DAGLink {
     this._nameBuf = null
     this._size = size
     this._cid = new CID(cid)
-
-    // Make sure we have a nice public API that can be used by an IPLD resolver
-    visibility.hidePrivateFields(this)
-    visibility.addEnumerableGetters(this, ['Hash', 'Name', 'Tsize'])
   }
 
   toString () {
diff --git a/src/dag-node/dagNode.js b/src/dag-node/dagNode.js
index 36d59cd..b8e7092 100644
--- a/src/dag-node/dagNode.js
+++ b/src/dag-node/dagNode.js
@@ -2,7 +2,6 @@
 
 const withIs = require('class-is')
 const sortLinks = require('./sortLinks')
-const visibility = require('../visibility')
 const DAGLink = require('../dag-link/dagLink')
 const { serializeDAGNode } = require('../serialize.js')
 const toDAGLink = require('./toDagLink')
@@ -38,10 +37,6 @@ class DAGNode {
     this._data = data
     this._links = links
     this._serializedSize = serializedSize
-
-    // Make sure we have a nice public API that can be used by an IPLD resolver
-    visibility.hidePrivateFields(this)
-    visibility.addEnumerableGetters(this, ['Data', 'Links'])
   }
 
   toJSON () {
diff --git a/src/resolver.js b/src/resolver.js
index a1888fb..d5ebed3 100644
--- a/src/resolver.js
+++ b/src/resolver.js
@@ -54,19 +54,6 @@ exports.resolve = (binaryBlob, path) => {
   }
 }
 
-const traverse = function * (node, path) {
-  // Traverse only objects and arrays
-  if (Buffer.isBuffer(node) || CID.isCID(node) || typeof node === 'string' ||
-      node === null) {
-    return
-  }
-  for (const item of Object.keys(node)) {
-    const nextpath = path === undefined ? item : path + '/' + item
-    yield nextpath
-    yield * traverse(node[item], nextpath)
-  }
-}
-
 /**
  * Return all available paths of a block.
  *
@@ -77,5 +64,13 @@ const traverse = function * (node, path) {
 exports.tree = function * (binaryBlob) {
   const node = util.deserialize(binaryBlob)
 
-  yield * traverse(node)
+  // There is always a `Data` and `Links` property
+  yield 'Data'
+  yield 'Links'
+  for (let ii = 0; ii < node.Links.length; ii++) {
+    yield `Links/${ii}`
+    yield `Links/${ii}/Name`
+    yield `Links/${ii}/Tsize`
+    yield `Links/${ii}/Hash`
+  }
 }
diff --git a/src/visibility.js b/src/visibility.js
deleted file mode 100644
index 02b1280..0000000
--- a/src/visibility.js
+++ /dev/null
@@ -1,53 +0,0 @@
-'use strict'
-
-/**
- * Make certain getters enumnerable
- *
- * This can be used to add additional getters that are enumerable and hence
- * show up on an `Object.keys()` call.
- *
- * @param {Object} object - The object it should be applied to
- * @param {Array.<String>} fields - The fields that should be made enumnerable
- */
-const addEnumerableGetters = (object, fields) => {
-  for (const field of fields) {
-    let prop
-    let proto = object
-    // Walk up the proottype chain until a property with the given name is
-    // found
-    while (prop === undefined) {
-      proto = Object.getPrototypeOf(proto)
-      if (proto === null) {
-        throw new Error(`no getter named '${field}' found`)
-      }
-      prop = Object.getOwnPropertyDescriptor(proto, field)
-    }
-
-    // There is a property with the correct name, but it's not a getter
-    if (prop.get === undefined) {
-      throw new Error(`no getter named '${field}' found`)
-    }
-    Object.defineProperty(object, field, {
-      enumerable: true,
-      get: prop.get
-    })
-  }
-}
-
-/**
- * Makes all properties with a leading underscore non-enumerable.
- *
- * @param {Object} object - The object it should be applied to
- */
-const hidePrivateFields = (object) => {
-  for (const key in object) {
-    if (key[0] === '_') {
-      Object.defineProperty(object, key, { enumerable: false })
-    }
-  }
-}
-
-module.exports = {
-  addEnumerableGetters,
-  hidePrivateFields
-}