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

@@ -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 () {

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 () {

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`
+  }
 }