change empty tree to [undefined, undfeind]

Signed-off-by: wanderer <mjbecze@gmail.com>

Author: wanderer

index.js

@@ -5,11 +5,6 @@ const TextEncoder = require('text-encoding').TextEncoder
 
 const encoder = new TextEncoder('utf-8')
 
-const LBRANCH = 0
-const RBRANCH = 1
-const EXTENSION = 2
-const VALUE = 3
-
 const RadixTree = module.exports = class RadixTree {
  /**
  * @param opts
@@ -18,10 +13,17 @@ const RadixTree = module.exports = class RadixTree {
  * @param opts.dag {object} an instance if [ipfs.dag](https://github.com/ipfs/js-ipfs#dag). If there is no `opts.graph` this will be used to create a new graph instance.
  */
  constructor (opts) {
- this.root = opts.root || {'/': undefined}
+ this.root = opts.root || {'/': RadixTree.emptyTreeState}
  this.graph = opts.graph || new Graph(opts.dag)
  }
 
+ /**
+ * returns the state of an empty tree
+ */
+ static get emptyTreeState () {
+ return [undefined, undefined]
+ }
+
  /**
  * returns an Uint1Array constructir which is used to repersent keys
  * @returns {object}
@@ -43,13 +45,14 @@ const RadixTree = module.exports = class RadixTree {
  let index = 0
  let root = this.root
  let parent
+
  while (1) {
  // load the root
  const exNode = await this.graph.get(root, EXTENSION, true)
  if (exNode) {
  let extensionIndex = 0
- const extensionLen = getExLength(root)
  const extension = getExtension(root)
+ const extensionLen = extension.length
  let subKey
  subKey = key.slice(index, index + extensionLen)
 
@@ -127,40 +130,35 @@ const RadixTree = module.exports = class RadixTree {
  value = {'/': value}
  }
 
- // initial set
- if (this.root['/'] === undefined) {
- this.root['/'] = createNode(key, [], value)['/']
+ const result = await this._get(key)
+ let root = result.root
+
+ if (result.value) {
+ setValue(root, value)
  } else {
- const result = await this._get(key)
- let root = result.root
+ if (result.extensionIndex !== undefined) {
+ // split the extension node in two
+ let extension = getExtension(root)
+ const extensionKey = extension[result.extensionIndex]
+ const remExtension = extension.subarray(result.extensionIndex + 1)
+ extension = extension.subarray(0, result.extensionIndex)
+
+ setExtension(root, remExtension)
+ const branch = []
+ branch[extensionKey] = {'/': root['/']}
+ root['/'] = createNode(extension, branch)['/']
+ }
 
- if (result.value) {
- setValue(root, value)
+ // if there are remaning key segments create an extension node
+ if (result.index < key.length) {
+ const keySegment = key[result.index]
+ const extension = key.subarray(result.index + 1, key.length)
+ const newNode = createNode(extension, [], value)
+ const rootBranch = getBranch(root)
+ rootBranch[keySegment] = newNode
+ setBranch(root, rootBranch)
  } else {
- if (result.extensionIndex !== undefined) {
- // split the extension node in two
- let extension = getExtension(root)
- const extensionKey = extension[result.extensionIndex]
- const remExtension = extension.subarray(result.extensionIndex + 1)
- extension = extension.subarray(0, result.extensionIndex)
-
- setExtension(root, remExtension)
- const branch = []
- branch[extensionKey] = {'/': root['/']}
- root['/'] = createNode(extension, branch)['/']
- }
-
- // if there are remaning key segments create an extension node
- if (result.index < key.length) {
- const keySegment = key[result.index]
- const extension = key.subarray(result.index + 1, key.length)
- const newNode = createNode(extension, [], value)
- const rootBranch = getBranch(root)
- rootBranch[keySegment] = newNode
- setBranch(root, rootBranch)
- } else {
- setValue(root, value)
- }
+ setValue(root, value)
  }
  }
  }
@@ -184,7 +182,7 @@ const RadixTree = module.exports = class RadixTree {
  joinNodes(root)
  } else {
  if (!parent) {
- root['/'] = undefined
+ root['/'] = RadixTree.emptyTreeState
  } else {
  let branch = getBranch(parent)
  branch = branch.map(node => node === root ? undefined : node)
@@ -257,6 +255,11 @@ function createNode (ex, branch, value) {
 }
 
 // helper functions for nodes
+const LBRANCH = 0
+const RBRANCH = 1
+const EXTENSION = 2
+const VALUE = 3
+
 function setBranch (node, branch) {
  node['/'][LBRANCH] = branch[0]
  node['/'][RBRANCH] = branch[1]
@@ -276,16 +279,13 @@ function deleteValue (node) {
 
 function getExtension (node) {
  if (node['/'][EXTENSION]) {
- return RadixTree.toTypedArray(node['/'][EXTENSION][1]).subarray(0, getExLength(node))
+ const len = node['/'][EXTENSION][0]
+ return RadixTree.toTypedArray(node['/'][EXTENSION][1]).subarray(0, len)
  } else {
  return []
  }
 }
 
-function getExLength (node) {
- return node['/'][EXTENSION][0]
-}
-
 function setExtension (node, ex) {
  if (ex && ex.length) {
  node['/'][EXTENSION] = [ex.length, Buffer.from(ex.buffer)]

tests/index.js

@@ -92,7 +92,7 @@ node.on('ready', () => {
  await tree.delete('te')
  await tree.delete('test')
  await tree.delete('ter')
- t.equals(tree.root['/'], undefined)
+ t.deepEquals(tree.root['/'], [undefined, undefined])
 
  // tests delete midle branchs
  await tree.set('test', 'cat')
@@ -107,7 +107,7 @@ node.on('ready', () => {
  await tree.delete('ter')
  await tree.delete('te')
  await tree.delete('test')
- t.equals(tree.root['/'], undefined)
+ t.deepEquals(tree.root['/'], [undefined, undefined])
  } catch (e) {
  console.log(e)
  }
@@ -146,7 +146,7 @@ node.on('ready', () => {
  await tree.delete(key)
  }
 
- t.equals(tree.root['/'], undefined)
+ t.deepEquals(tree.root['/'], [undefined, undefined])
 
  t.end()
  })