start refactoring

lib/NamedEventHandler.js

@@ -0,0 +1,113 @@
+
+/**
+ * Handles named events.
+ */
+export default class NamedEventHandler {
+  constructor () {
+    this._eventListener = new Map()
+    this._stateListener = new Map()
+  }
+
+  /**
+   * @private
+   * Returns all listeners that listen to a specified name.
+   *
+   * @param {String} name The query event name.
+   */
+  _getListener (name) {
+    let listeners = this._eventListener.get(name)
+    if (listeners === undefined) {
+      listeners = {
+        once: new Set(),
+        on: new Set()
+      }
+      this._eventListener.set(name, listeners)
+    }
+    return listeners
+  }
+
+  /**
+   * Adds a named event listener. The listener is removed after it has been
+   * called once.
+   *
+   * @param {String} name The event name to listen to.
+   * @param {Function} f The function that is executed when the event is fired.
+   */
+  once (name, f) {
+    let listeners = this._getListener(name)
+    listeners.once.add(f)
+  }
+
+  /**
+   * Adds a named event listener.
+   *
+   * @param {String} name The event name to listen to.
+   * @param {Function} f The function that is executed when the event is fired.
+   */
+  on (name, f) {
+    let listeners = this._getListener(name)
+    listeners.on.add(f)
+  }
+
+  /**
+   * @private
+   * Init the saved state for an event name.
+   */
+  _initStateListener (name) {
+    let state = this._stateListener.get(name)
+    if (state === undefined) {
+      state = {}
+      state.promise = new Promise(function (resolve) {
+        state.resolve = resolve
+      })
+      this._stateListener.set(name, state)
+    }
+    return state
+  }
+
+  /**
+   * Returns a Promise that is resolved when the event name is called.
+   * The Promise is immediately resolved when the event name was called in the
+   * past.
+   */
+  when (name) {
+    return this._initStateListener(name).promise
+  }
+
+  /**
+   * Remove an event listener that was registered with either
+   * {@link EventHandler#on} or {@link EventHandler#once}.
+   */
+  off (name, f) {
+    if (name == null || f == null) {
+      throw new Error('You must specify event name and function!')
+    }
+    const listener = this._eventListener.get(name)
+    if (listener !== undefined) {
+      listener.on.delete(f)
+      listener.once.delete(f)
+    }
+  }
+
+  /**
+   * Emit a named event. All registered event listeners that listen to the
+   * specified name will receive the event.
+   *
+   * @param {String} name The event name.
+   * @param {Array} args The arguments that are applied to the event listener.
+   */
+  emit (name, ...args) {
+    this._initStateListener(name).resolve()
+    const listener = this._eventListener.get(name)
+    if (listener !== undefined) {
+      listener.on.forEach(f => f.apply(null, args))
+      listener.once.forEach(f => f.apply(null, args))
+      listener.once = new Set()
+    } else if (name === 'error') {
+      console.error(args[0])
+    }
+  }
+  destroy () {
+    this._eventListener = null
+  }
+}

lib/Tree.js

@@ -0,0 +1,465 @@
+
+function rotate (tree, parent, newParent, n) {
+  if (parent === null) {
+    tree.root = newParent
+    newParent._parent = null
+  } else if (parent.left === n) {
+    parent.left = newParent
+  } else if (parent.right === n) {
+    parent.right = newParent
+  } else {
+    throw new Error('The elements are wrongly connected!')
+  }
+}
+
+class N {
+  // A created node is always red!
+  constructor (val) {
+    this.val = val
+    this.color = true
+    this._left = null
+    this._right = null
+    this._parent = null
+  }
+  isRed () { return this.color }
+  isBlack () { return !this.color }
+  redden () { this.color = true; return this }
+  blacken () { this.color = false; return this }
+  get grandparent () {
+    return this.parent.parent
+  }
+  get parent () {
+    return this._parent
+  }
+  get sibling () {
+    return (this === this.parent.left)
+      ? this.parent.right : this.parent.left
+  }
+  get left () {
+    return this._left
+  }
+  get right () {
+    return this._right
+  }
+  set left (n) {
+    if (n !== null) {
+      n._parent = this
+    }
+    this._left = n
+  }
+  set right (n) {
+    if (n !== null) {
+      n._parent = this
+    }
+    this._right = n
+  }
+  rotateLeft (tree) {
+    const parent = this.parent
+    const newParent = this.right
+    const newRight = this.right.left
+    newParent.left = this
+    this.right = newRight
+    rotate(tree, parent, newParent, this)
+  }
+  next () {
+    if (this.right !== null) {
+      // search the most left node in the right tree
+      var o = this.right
+      while (o.left !== null) {
+        o = o.left
+      }
+      return o
+    } else {
+      var p = this
+      while (p.parent !== null && p !== p.parent.left) {
+        p = p.parent
+      }
+      return p.parent
+    }
+  }
+  prev () {
+    if (this.left !== null) {
+      // search the most right node in the left tree
+      var o = this.left
+      while (o.right !== null) {
+        o = o.right
+      }
+      return o
+    } else {
+      var p = this
+      while (p.parent !== null && p !== p.parent.right) {
+        p = p.parent
+      }
+      return p.parent
+    }
+  }
+  rotateRight (tree) {
+    const parent = this.parent
+    const newParent = this.left
+    const newLeft = this.left.right
+    newParent.right = this
+    this.left = newLeft
+    rotate(tree, parent, newParent, this)
+  }
+  getUncle () {
+    // we can assume that grandparent exists when this is called!
+    if (this.parent === this.parent.parent.left) {
+      return this.parent.parent.right
+    } else {
+      return this.parent.parent.left
+    }
+  }
+}
+
+/*
+ * This is a Red Black Tree implementation
+ */
+export default class Tree {
+  constructor () {
+    this.root = null
+    this.length = 0
+  }
+  findNext (id) {
+    var nextID = id.clone()
+    nextID.clock += 1
+    return this.findWithLowerBound(nextID)
+  }
+  findPrev (id) {
+    let prevID = id.clone()
+    prevID.clock -= 1
+    return this.findWithUpperBound(prevID)
+  }
+  findNodeWithLowerBound (from) {
+    var o = this.root
+    if (o === null) {
+      return null
+    } else {
+      while (true) {
+        if (from === null || (from.lessThan(o.val._id) && o.left !== null)) {
+          // o is included in the bound
+          // try to find an element that is closer to the bound
+          o = o.left
+        } else if (from !== null && o.val._id.lessThan(from)) {
+          // o is not within the bound, maybe one of the right elements is..
+          if (o.right !== null) {
+            o = o.right
+          } else {
+            // there is no right element. Search for the next bigger element,
+            // this should be within the bounds
+            return o.next()
+          }
+        } else {
+          return o
+        }
+      }
+    }
+  }
+  findNodeWithUpperBound (to) {
+    if (to === void 0) {
+      throw new Error('You must define from!')
+    }
+    var o = this.root
+    if (o === null) {
+      return null
+    } else {
+      while (true) {
+        if ((to === null || o.val._id.lessThan(to)) && o.right !== null) {
+          // o is included in the bound
+          // try to find an element that is closer to the bound
+          o = o.right
+        } else if (to !== null && to.lessThan(o.val._id)) {
+          // o is not within the bound, maybe one of the left elements is..
+          if (o.left !== null) {
+            o = o.left
+          } else {
+            // there is no left element. Search for the prev smaller element,
+            // this should be within the bounds
+            return o.prev()
+          }
+        } else {
+          return o
+        }
+      }
+    }
+  }
+  findSmallestNode () {
+    var o = this.root
+    while (o != null && o.left != null) {
+      o = o.left
+    }
+    return o
+  }
+  findWithLowerBound (from) {
+    var n = this.findNodeWithLowerBound(from)
+    return n == null ? null : n.val
+  }
+  findWithUpperBound (to) {
+    var n = this.findNodeWithUpperBound(to)
+    return n == null ? null : n.val
+  }
+  iterate (from, to, f) {
+    var o
+    if (from === null) {
+      o = this.findSmallestNode()
+    } else {
+      o = this.findNodeWithLowerBound(from)
+    }
+    while (
+      o !== null &&
+      (
+        to === null || // eslint-disable-line no-unmodified-loop-condition
+        o.val._id.lessThan(to) ||
+        o.val._id.equals(to)
+      )
+    ) {
+      f(o.val)
+      o = o.next()
+    }
+  }
+  find (id) {
+    let n = this.findNode(id)
+    if (n !== null) {
+      return n.val
+    } else {
+      return null
+    }
+  }
+  findNode (id) {
+    var o = this.root
+    if (o === null) {
+      return null
+    } else {
+      while (true) {
+        if (o === null) {
+          return null
+        }
+        if (id.lessThan(o.val._id)) {
+          o = o.left
+        } else if (o.val._id.lessThan(id)) {
+          o = o.right
+        } else {
+          return o
+        }
+      }
+    }
+  }
+  delete (id) {
+    var d = this.findNode(id)
+    if (d == null) {
+      // throw new Error('Element does not exist!')
+      return
+    }
+    this.length--
+    if (d.left !== null && d.right !== null) {
+      // switch d with the greates element in the left subtree.
+      // o should have at most one child.
+      var o = d.left
+      // find
+      while (o.right !== null) {
+        o = o.right
+      }
+      // switch
+      d.val = o.val
+      d = o
+    }
+    // d has at most one child
+    // let n be the node that replaces d
+    var isFakeChild
+    var child = d.left || d.right
+    if (child === null) {
+      isFakeChild = true
+      child = new N(null)
+      child.blacken()
+      d.right = child
+    } else {
+      isFakeChild = false
+    }
+
+    if (d.parent === null) {
+      if (!isFakeChild) {
+        this.root = child
+        child.blacken()
+        child._parent = null
+      } else {
+        this.root = null
+      }
+      return
+    } else if (d.parent.left === d) {
+      d.parent.left = child
+    } else if (d.parent.right === d) {
+      d.parent.right = child
+    } else {
+      throw new Error('Impossible!')
+    }
+    if (d.isBlack()) {
+      if (child.isRed()) {
+        child.blacken()
+      } else {
+        this._fixDelete(child)
+      }
+    }
+    this.root.blacken()
+    if (isFakeChild) {
+      if (child.parent.left === child) {
+        child.parent.left = null
+      } else if (child.parent.right === child) {
+        child.parent.right = null
+      } else {
+        throw new Error('Impossible #3')
+      }
+    }
+  }
+  _fixDelete (n) {
+    function isBlack (node) {
+      return node !== null ? node.isBlack() : true
+    }
+    function isRed (node) {
+      return node !== null ? node.isRed() : false
+    }
+    if (n.parent === null) {
+      // this can only be called after the first iteration of fixDelete.
+      return
+    }
+    // d was already replaced by the child
+    // d is not the root
+    // d and child are black
+    var sibling = n.sibling
+    if (isRed(sibling)) {
+      // make sibling the grandfather
+      n.parent.redden()
+      sibling.blacken()
+      if (n === n.parent.left) {
+        n.parent.rotateLeft(this)
+      } else if (n === n.parent.right) {
+        n.parent.rotateRight(this)
+      } else {
+        throw new Error('Impossible #2')
+      }
+      sibling = n.sibling
+    }
+    // parent, sibling, and children of n are black
+    if (n.parent.isBlack() &&
+      sibling.isBlack() &&
+      isBlack(sibling.left) &&
+      isBlack(sibling.right)
+    ) {
+      sibling.redden()
+      this._fixDelete(n.parent)
+    } else if (n.parent.isRed() &&
+      sibling.isBlack() &&
+      isBlack(sibling.left) &&
+      isBlack(sibling.right)
+    ) {
+      sibling.redden()
+      n.parent.blacken()
+    } else {
+      if (n === n.parent.left &&
+        sibling.isBlack() &&
+        isRed(sibling.left) &&
+        isBlack(sibling.right)
+      ) {
+        sibling.redden()
+        sibling.left.blacken()
+        sibling.rotateRight(this)
+        sibling = n.sibling
+      } else if (n === n.parent.right &&
+        sibling.isBlack() &&
+        isRed(sibling.right) &&
+        isBlack(sibling.left)
+      ) {
+        sibling.redden()
+        sibling.right.blacken()
+        sibling.rotateLeft(this)
+        sibling = n.sibling
+      }
+      sibling.color = n.parent.color
+      n.parent.blacken()
+      if (n === n.parent.left) {
+        sibling.right.blacken()
+        n.parent.rotateLeft(this)
+      } else {
+        sibling.left.blacken()
+        n.parent.rotateRight(this)
+      }
+    }
+  }
+  put (v) {
+    var node = new N(v)
+    if (this.root !== null) {
+      var p = this.root // p abbrev. parent
+      while (true) {
+        if (node.val._id.lessThan(p.val._id)) {
+          if (p.left === null) {
+            p.left = node
+            break
+          } else {
+            p = p.left
+          }
+        } else if (p.val._id.lessThan(node.val._id)) {
+          if (p.right === null) {
+            p.right = node
+            break
+          } else {
+            p = p.right
+          }
+        } else {
+          p.val = node.val
+          return p
+        }
+      }
+      this._fixInsert(node)
+    } else {
+      this.root = node
+    }
+    this.length++
+    this.root.blacken()
+    return node
+  }
+  _fixInsert (n) {
+    if (n.parent === null) {
+      n.blacken()
+      return
+    } else if (n.parent.isBlack()) {
+      return
+    }
+    var uncle = n.getUncle()
+    if (uncle !== null && uncle.isRed()) {
+      // Note: parent: red, uncle: red
+      n.parent.blacken()
+      uncle.blacken()
+      n.grandparent.redden()
+      this._fixInsert(n.grandparent)
+    } else {
+      // Note: parent: red, uncle: black or null
+      // Now we transform the tree in such a way that
+      // either of these holds:
+      //   1) grandparent.left.isRed
+      //     and grandparent.left.left.isRed
+      //   2) grandparent.right.isRed
+      //     and grandparent.right.right.isRed
+      if (n === n.parent.right && n.parent === n.grandparent.left) {
+        n.parent.rotateLeft(this)
+        // Since we rotated and want to use the previous
+        // cases, we need to set n in such a way that
+        // n.parent.isRed again
+        n = n.left
+      } else if (n === n.parent.left && n.parent === n.grandparent.right) {
+        n.parent.rotateRight(this)
+        // see above
+        n = n.right
+      }
+      // Case 1) or 2) hold from here on.
+      // Now traverse grandparent, make parent a black node
+      // on the highest level which holds two red nodes.
+      n.parent.blacken()
+      n.grandparent.redden()
+      if (n === n.parent.left) {
+        // Case 1
+        n.grandparent.rotateRight(this)
+      } else {
+        // Case 2
+        n.grandparent.rotateLeft(this)
+      }
+    }
+  }
+}

lib/decoding.js

@@ -0,0 +1,188 @@
+
+/* global Buffer */
+
+import * as globals from './globals.js'
+
+/**
+ * A Decoder handles the decoding of an ArrayBuffer.
+ */
+class Decoder {
+  /**
+   * @param {ArrayBuffer} buffer Binary data to decode
+   */
+  constructor (buffer) {
+    this.arr = new Uint8Array(buffer)
+    this.pos = 0
+  }
+}
+
+/**
+ * @param {ArrayBuffer} buffer
+ * @return {Decoder}
+ */
+export const createDecoder = buffer => new Decoder(buffer)
+
+export const hasContent = decoder => decoder.pos !== decoder.arr.length
+
+/**
+ * Clone a decoder instance.
+ * Optionally set a new position parameter.
+ * @param {Decoder} decoder The decoder instance
+ * @return {Decoder} A clone of `decoder`
+ */
+export const clone = (decoder, newPos = decoder.pos) => {
+  let _decoder = createDecoder(decoder.arr.buffer)
+  _decoder.pos = newPos
+  return _decoder
+}
+
+/**
+ * Read `len` bytes as an ArrayBuffer.
+ * @param {Decoder} decoder The decoder instance
+ * @param {number} len The length of bytes to read
+ * @return {ArrayBuffer}
+ */
+export const readArrayBuffer = (decoder, len) => {
+  const arrayBuffer = globals.createUint8ArrayFromLen(len)
+  const view = globals.createUint8ArrayFromBuffer(decoder.arr.buffer, decoder.pos, len)
+  arrayBuffer.set(view)
+  decoder.pos += len
+  return arrayBuffer.buffer
+}
+
+/**
+ * Read variable length payload as ArrayBuffer
+ * @param {Decoder} decoder
+ * @return {ArrayBuffer}
+ */
+export const readPayload = decoder => readArrayBuffer(decoder, readVarUint(decoder))
+
+/**
+ * Read the rest of the content as an ArrayBuffer
+ * @param {Decoder} decoder
+ * @return {ArrayBuffer}
+ */
+export const readTail = decoder => readArrayBuffer(decoder, decoder.arr.length - decoder.pos)
+
+/**
+ * Skip one byte, jump to the next position.
+ * @param {Decoder} decoder The decoder instance
+ * @return {number} The next position
+ */
+export const skip8 = decoder => decoder.pos++
+
+/**
+ * Read one byte as unsigned integer.
+ * @param {Decoder} decoder The decoder instance
+ * @return {number} Unsigned 8-bit integer
+ */
+export const readUint8 = decoder => decoder.arr[decoder.pos++]
+
+/**
+ * Read 4 bytes as unsigned integer.
+ *
+ * @param {Decoder} decoder
+ * @return {number} An unsigned integer.
+ */
+export const readUint32 = decoder => {
+  let uint =
+    decoder.arr[decoder.pos] +
+    (decoder.arr[decoder.pos + 1] << 8) +
+    (decoder.arr[decoder.pos + 2] << 16) +
+    (decoder.arr[decoder.pos + 3] << 24)
+  decoder.pos += 4
+  return uint
+}
+
+/**
+ * Look ahead without incrementing position.
+ * to the next byte and read it as unsigned integer.
+ *
+ * @param {Decoder} decoder
+ * @return {number} An unsigned integer.
+ */
+export const peekUint8 = decoder => decoder.arr[decoder.pos]
+
+/**
+ * Read unsigned integer (32bit) with variable length.
+ * 1/8th of the storage is used as encoding overhead.
+ *  * numbers < 2^7 is stored in one bytlength
+ *  * numbers < 2^14 is stored in two bylength
+ *
+ * @param {Decoder} decoder
+ * @return {number} An unsigned integer.length
+ */
+export const readVarUint = decoder => {
+  let num = 0
+  let len = 0
+  while (true) {
+    let r = decoder.arr[decoder.pos++]
+    num = num | ((r & 0b1111111) << len)
+    len += 7
+    if (r < 1 << 7) {
+      return num >>> 0 // return unsigned number!
+    }
+    if (len > 35) {
+      throw new Error('Integer out of range!')
+    }
+  }
+}
+
+/**
+ * Read string of variable length
+ * * varUint is used to store the length of the string
+ *
+ * Transforming utf8 to a string is pretty expensive. The code performs 10x better
+ * when String.fromCodePoint is fed with all characters as arguments.
+ * But most environments have a maximum number of arguments per functions.
+ * For effiency reasons we apply a maximum of 10000 characters at once.
+ *
+ * @param {Decoder} decoder
+ * @return {String} The read String.
+ */
+export const readVarString = decoder => {
+  let remainingLen = readVarUint(decoder)
+  let encodedString = ''
+  while (remainingLen > 0) {
+    const nextLen = remainingLen < 10000 ? remainingLen : 10000
+    const bytes = new Array(nextLen)
+    for (let i = 0; i < nextLen; i++) {
+      bytes[i] = decoder.arr[decoder.pos++]
+    }
+    encodedString += String.fromCodePoint.apply(null, bytes)
+    remainingLen -= nextLen
+  }
+  return decodeURIComponent(escape(encodedString))
+}
+
+/**
+ * Look ahead and read varString without incrementing position
+ * @param {Decoder} decoder
+ * @return {string}
+ */
+export const peekVarString = decoder => {
+  let pos = decoder.pos
+  let s = readVarString(decoder)
+  decoder.pos = pos
+  return s
+}
+
+/**
+ * Read ID.
+ * * If first varUint read is 0xFFFFFF a RootID is returned.
+ * * Otherwise an ID is returned
+ *
+ * @param {Decoder} decoder
+ * @return {ID}
+ *
+export const readID = decoder => {
+  let user = decoder.readVarUint()
+  if (user === RootFakeUserID) {
+    // read property name and type id
+    const rid = new RootID(decoder.readVarString(), null)
+    rid.type = decoder.readVarUint()
+    return rid
+  }
+  return new ID(user, decoder.readVarUint())
+}
+*/

lib/encoding.js

@@ -0,0 +1,234 @@
+
+import * as globals from './globals.js'
+
+const bits7 = 0b1111111
+const bits8 = 0b11111111
+
+/**
+ * A BinaryEncoder handles the encoding to an ArrayBuffer.
+ */
+class Encoder {
+  constructor () {
+    this.cpos = 0
+    this.cbuf = globals.createUint8ArrayFromLen(1000)
+    this.bufs = []
+  }
+}
+
+export const createEncoder = () => new Encoder()
+
+/**
+ * The current length of the encoded data.
+ */
+export const length = encoder => {
+  let len = 0
+  for (let i = 0; i < encoder.bufs.length; i++) {
+    len += encoder.bufs[i].length
+  }
+  len += encoder.cpos
+  return len
+}
+
+/**
+ * Transform to ArrayBuffer.
+ * @param {Encoder} encoder
+ * @return {ArrayBuffer} The created ArrayBuffer.
+ */
+export const toBuffer = encoder => {
+  const uint8arr = globals.createUint8ArrayFromLen(length(encoder))
+  let curPos = 0
+  for (let i = 0; i < encoder.bufs.length; i++) {
+    let d = encoder.bufs[i]
+    uint8arr.set(d, curPos)
+    curPos += d.length
+  }
+  uint8arr.set(globals.createUint8ArrayFromBuffer(encoder.cbuf.buffer, 0, encoder.cpos), curPos)
+  return uint8arr.buffer
+}
+
+/**
+ * Write one byte to the encoder.
+ *
+ * @param {Encoder} encoder
+ * @param {number} num The byte that is to be encoded.
+ */
+export const write = (encoder, num) => {
+  if (encoder.cpos === encoder.cbuf.length) {
+    encoder.bufs.push(encoder.cbuf)
+    encoder.cbuf = globals.createUint8ArrayFromLen(encoder.cbuf.length * 2)
+    encoder.cpos = 0
+  }
+  encoder.cbuf[encoder.cpos++] = num
+}
+
+/**
+ * Write one byte at a specific position.
+ * Position must already be written (i.e. encoder.length > pos)
+ *
+ * @param {Encoder} encoder
+ * @param {number} pos Position to which to write data
+ * @param {number} num Unsigned 8-bit integer
+ */
+export const set = (encoder, pos, num) => {
+  let buffer = null
+  // iterate all buffers and adjust position
+  for (let i = 0; i < encoder.bufs.length && buffer === null; i++) {
+    const b = encoder.bufs[i]
+    if (pos < b.length) {
+      buffer = b // found buffer
+    } else {
+      pos -= b.length
+    }
+  }
+  if (buffer === null) {
+    // use current buffer
+    buffer = encoder.cbuf
+  }
+  buffer[pos] = num
+}
+
+/**
+ * Write one byte as an unsigned integer.
+ *
+ * @param {Encoder} encoder
+ * @param {number} num The number that is to be encoded.
+ */
+export const writeUint8 = (encoder, num) => write(encoder, num & bits8)
+
+/**
+ * Write one byte as an unsigned Integer at a specific location.
+ *
+ * @param {Encoder} encoder
+ * @param {number} pos The location where the data will be written.
+ * @param {number} num The number that is to be encoded.
+ */
+export const setUint8 = (encoder, pos, num) => set(encoder, pos, num & bits8)
+
+/**
+ * Write two bytes as an unsigned integer.
+ *
+ * @param {Encoder} encoder
+ * @param {number} num The number that is to be encoded.
+ */
+export const writeUint16 = (encoder, num) => {
+  write(encoder, num & bits8)
+  write(encoder, (num >>> 8) & bits8)
+}
+/**
+ * Write two bytes as an unsigned integer at a specific location.
+ *
+ * @param {Encoder} encoder
+ * @param {number} pos The location where the data will be written.
+ * @param {number} num The number that is to be encoded.
+ */
+export const setUint16 = (encoder, pos, num) => {
+  set(encoder, pos, num & bits8)
+  set(encoder, pos + 1, (num >>> 8) & bits8)
+}
+
+/**
+ * Write two bytes as an unsigned integer
+ *
+ * @param {Encoder} encoder
+ * @param {number} num The number that is to be encoded.
+ */
+export const writeUint32 = (encoder, num) => {
+  for (let i = 0; i < 4; i++) {
+    write(encoder, num & bits8)
+    num >>>= 8
+  }
+}
+
+/**
+ * Write two bytes as an unsigned integer at a specific location.
+ *
+ * @param {Encoder} encoder
+ * @param {number} pos The location where the data will be written.
+ * @param {number} num The number that is to be encoded.
+ */
+export const setUint32 = (encoder, pos, num) => {
+  for (let i = 0; i < 4; i++) {
+    set(encoder, pos + i, num & bits8)
+    num >>>= 8
+  }
+}
+
+/**
+ * Write a variable length unsigned integer.
+ *
+ * Encodes integers in the range from [0, 4294967295] / [0, 0xffffffff]. (max 32 bit unsigned integer)
+ *
+ * @param {Encoder} encoder
+ * @param {number} num The number that is to be encoded.
+ */
+export const writeVarUint = (encoder, num) => {
+  while (num >= 0b10000000) {
+    write(encoder, 0b10000000 | (bits7 & num))
+    num >>>= 7
+  }
+  write(encoder, bits7 & num)
+}
+
+/**
+ * Write a variable length string.
+ *
+ * @param {Encoder} encoder
+ * @param {String} str The string that is to be encoded.
+ */
+export const writeVarString = (encoder, str) => {
+  const encodedString = unescape(encodeURIComponent(str))
+  const len = encodedString.length
+  writeVarUint(encoder, len)
+  for (let i = 0; i < len; i++) {
+    write(encoder, encodedString.codePointAt(i))
+  }
+}
+
+/**
+ * Write the content of another biUint8Arr
+ *
+ * @param {Encoder} encoder The enUint8Arr
+ * @param encoderToAppend The BinaryEncoder to be written.
+ */
+export const writeBinaryEncoder = (encoder, encoderToAppend) => writeArrayBuffer(encoder, toBuffer(encoder))
+
+/**
+ * Append an arrayBuffer to the encoder.
+ *
+ * @param {Encoder} encoder
+ * @param {ArrayBuffer} arrayBuffer
+ */
+export const writeArrayBuffer = (encoder, arrayBuffer) => {
+  const prevBufferLen = encoder.cbuf.length
+  // TODO: Append to cbuf if possible
+  encoder.bufs.push(globals.createUint8ArrayFromBuffer(encoder.cbuf.buffer, 0, encoder.cpos))
+  encoder.bufs.push(globals.createUint8ArrayFromArrayBuffer(arrayBuffer))
+  encoder.cbuf = globals.createUint8ArrayFromLen(prevBufferLen)
+  encoder.cpos = 0
+}
+
+/**
+ * @param {Encoder} encoder
+ * @param {ArrayBuffer} arrayBuffer
+ */
+export const writePayload = (encoder, arrayBuffer) => {
+  writeVarUint(encoder, arrayBuffer.byteLength)
+  writeArrayBuffer(encoder, arrayBuffer)
+}
+
+/**
+ * Write an ID at the current position.
+ *
+ * @param {ID} id The ID that is to be written.
+ *
+export const writeID = (encoder, id) => {
+  const user = id.user
+  writeVarUint(encoder, user)
+  if (user !== RootFakeUserID) {
+    writeVarUint(encoder, id.clock)
+  } else {
+    writeVarString(encoder, id.name)
+    writeVarUint(encoder, id.type)
+  }
+}
+*/

lib/encoding.test.js

@@ -0,0 +1,49 @@
+import * as encoding from './encoding.js'
+
+/**
+ * Check if binary encoding is compatible with golang binary encoding - binary.PutVarUint.
+ *
+ * Result: is compatible up to 32 bit: [0, 4294967295] / [0, 0xffffffff]. (max 32 bit unsigned integer)
+ */
+let err = null
+try {
+  const tests = [
+    { in: 0, out: [0] },
+    { in: 1, out: [1] },
+    { in: 128, out: [128, 1] },
+    { in: 200, out: [200, 1] },
+    { in: 32, out: [32] },
+    { in: 500, out: [244, 3] },
+    { in: 256, out: [128, 2] },
+    { in: 700, out: [188, 5] },
+    { in: 1024, out: [128, 8] },
+    { in: 1025, out: [129, 8] },
+    { in: 4048, out: [208, 31] },
+    { in: 5050, out: [186, 39] },
+    { in: 1000000, out: [192, 132, 61] },
+    { in: 34951959, out: [151, 166, 213, 16] },
+    { in: 2147483646, out: [254, 255, 255, 255, 7] },
+    { in: 2147483647, out: [255, 255, 255, 255, 7] },
+    { in: 2147483648, out: [128, 128, 128, 128, 8] },
+    { in: 2147483700, out: [180, 128, 128, 128, 8] },
+    { in: 4294967294, out: [254, 255, 255, 255, 15] },
+    { in: 4294967295, out: [255, 255, 255, 255, 15] }
+  ]
+  tests.forEach(test => {
+    const encoder = encoding.createEncoder()
+    encoding.writeVarUint(encoder, test.in)
+    const buffer = new Uint8Array(encoding.toBuffer(encoder))
+    if (buffer.byteLength !== test.out.length) {
+      throw new Error('Length don\'t match!')
+    }
+    for (let j = 0; j < buffer.length; j++) {
+      if (buffer[j] !== test[1][j]) {
+        throw new Error('values don\'t match!')
+      }
+    }
+  })
+} catch (error) {
+  err = error
+} finally {
+  console.log('YDB Client: Encoding varUint compatiblity test: ', err || 'success!')
+}

lib/globals.js

@@ -0,0 +1,59 @@
+/* eslint-env browser */
+
+export const Uint8Array_ = Uint8Array
+
+/**
+ * @param {Array<number>} arr
+ * @return {ArrayBuffer}
+ */
+export const createArrayBufferFromArray = arr => new Uint8Array_(arr).buffer
+
+export const createUint8ArrayFromLen = len => new Uint8Array_(len)
+
+/**
+ * Create Uint8Array with initial content from buffer
+ */
+export const createUint8ArrayFromBuffer = (buffer, byteOffset, length) => new Uint8Array_(buffer, byteOffset, length)
+
+/**
+ * Create Uint8Array with initial content from buffer
+ */
+export const createUint8ArrayFromArrayBuffer = arraybuffer => new Uint8Array_(arraybuffer)
+export const createArrayFromArrayBuffer = arraybuffer => Array.from(createUint8ArrayFromArrayBuffer(arraybuffer))
+
+export const createPromise = f => new Promise(f)
+/**
+ * `Promise.all` wait for all promises in the array to resolve and return the result
+ * @param {Array<Promise<any>>} arrp
+ * @return {any}
+ */
+export const pall = arrp => Promise.all(arrp)
+export const preject = reason => Promise.reject(reason)
+export const presolve = res => Promise.resolve(res)
+
+export const until = (timeout, check) => createPromise((resolve, reject) => {
+  const hasTimeout = timeout > 0
+  const untilInterval = () => {
+    if (check()) {
+      clearInterval(intervalHandle)
+      resolve()
+    } else if (hasTimeout) {
+      timeout -= 10
+      if (timeout < 0) {
+        clearInterval(intervalHandle)
+        reject(error('Timeout'))
+      }
+    }
+  }
+  const intervalHandle = setInterval(untilInterval, 10)
+})
+
+export const error = description => new Error(description)
+
+export const max = (a, b) => a > b ? a : b
+
+/**
+ * @param {number} t Time to wait
+ * @return {Promise} Promise that is resolved after t ms
+ */
+export const wait = t => createPromise(r => setTimeout(r, t))

lib/idb.js

@@ -0,0 +1,144 @@
+/* eslint-env browser */
+
+import * as globals from './globals.js'
+
+/*
+ * IDB Request to Promise transformer
+ */
+export const rtop = request => globals.createPromise((resolve, reject) => {
+  request.onerror = event => reject(new Error(event.target.error))
+  request.onblocked = () => location.reload()
+  request.onsuccess = event => resolve(event.target.result)
+})
+
+/**
+ * @return {Promise<IDBDatabase>}
+ */
+export const openDB = (name, initDB) => globals.createPromise((resolve, reject) => {
+  let request = indexedDB.open(name)
+  /**
+   * @param {any} event
+   */
+  request.onupgradeneeded = event => initDB(event.target.result)
+  /**
+   * @param {any} event
+   */
+  request.onerror = event => reject(new Error(event.target.error))
+  request.onblocked = () => location.reload()
+  /**
+   * @param {any} event
+   */
+  request.onsuccess = event => {
+    const db = event.target.result
+    db.onversionchange = () => { db.close() }
+    addEventListener('unload', () => db.close())
+    resolve(db)
+  }
+})
+
+export const deleteDB = name => rtop(indexedDB.deleteDatabase(name))
+
+export const createStores = (db, definitions) => definitions.forEach(d =>
+  db.createObjectStore.apply(db, d)
+)
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {String | number | ArrayBuffer | Date | Array } key
+ * @return {Promise<ArrayBuffer>}
+ */
+export const get = (store, key) =>
+  rtop(store.get(key))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {String | number | ArrayBuffer | Date | IDBKeyRange | Array } key
+ */
+export const del = (store, key) =>
+  rtop(store.delete(key))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {String | number | ArrayBuffer | Date | boolean} item
+ * @param {String | number | ArrayBuffer | Date | Array} [key]
+ */
+export const put = (store, item, key) =>
+  rtop(store.put(item, key))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {String | number | ArrayBuffer | Date | boolean}  item
+ * @param {String | number | ArrayBuffer | Date | Array}  [key]
+ * @return {Promise<ArrayBuffer>}
+ */
+export const add = (store, item, key) =>
+  rtop(store.add(item, key))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {String | number | ArrayBuffer | Date}  item
+ * @return {Promise<number>}
+ */
+export const addAutoKey = (store, item) =>
+  rtop(store.add(item))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {IDBKeyRange} [range]
+ */
+export const getAll = (store, range) =>
+  rtop(store.getAll(range))
+
+/**
+ * @param {IDBObjectStore} store
+ * @param {IDBKeyRange} [range]
+ */
+export const getAllKeys = (store, range) =>
+  rtop(store.getAllKeys(range))
+
+/**
+ * Iterate on keys and values
+ * @param {IDBObjectStore} store
+ * @param {IDBKeyRange?} keyrange
+ * @param {function(any, any)} f Return true in order to continue the cursor
+ */
+export const iterate = (store, keyrange, f) => globals.createPromise((resolve, reject) => {
+  const request = store.openCursor(keyrange)
+  request.onerror = reject
+  /**
+   * @param {any} event
+   */
+  request.onsuccess = event => {
+    const cursor = event.target.result
+    if (cursor === null) {
+      return resolve()
+    }
+    f(cursor.value, cursor.key)
+    cursor.continue()
+  }
+})
+
+/**
+ * Iterate on the keys (no values)
+ * @param {IDBObjectStore} store
+ * @param {IDBKeyRange} keyrange
+ * @param {function(IDBCursor)} f Call `idbcursor.continue()` to iterate further
+ */
+export const iterateKeys = (store, keyrange, f) => {
+  /**
+   * @param {any} event
+   */
+  store.openKeyCursor(keyrange).onsuccess = event => f(event.target.result)
+}
+
+/**
+ * Open store from transaction
+ * @param {IDBTransaction} t
+ * @param {String} store
+ * @returns {IDBObjectStore}
+ */
+export const getStore = (t, store) => t.objectStore(store)
+
+export const createIDBKeyRangeBound = (lower, upper, lowerOpen, upperOpen) => IDBKeyRange.bound(lower, upper, lowerOpen, upperOpen)
+export const createIDBKeyRangeUpperBound = (upper, upperOpen) => IDBKeyRange.upperBound(upper, upperOpen)
+export const createIDBKeyRangeLowerBound = (lower, lowerOpen) => IDBKeyRange.lowerBound(lower, lowerOpen)

lib/idb.test.js

@@ -0,0 +1,34 @@
+import * as test from './test.js'
+import * as idb from './idb.js'
+import * as logging from './logging.js'
+
+const initTestDB = db => idb.createStores(db, [['test']])
+const testDBName = 'idb-test'
+
+const createTransaction = db => db.transaction(['test'], 'readwrite')
+/**
+ * @param {IDBTransaction} t
+ * @return {IDBObjectStore}
+ */
+const getStore = t => idb.getStore(t, 'test')
+
+idb.deleteDB(testDBName).then(() => idb.openDB(testDBName, initTestDB)).then(db => {
+  test.run('idb iteration', async testname => {
+    const t = createTransaction(db)
+    await idb.put(getStore(t), 0, ['t', 0])
+    await idb.put(getStore(t), 1, ['t', 1])
+    const valsGetAll = await idb.getAll(getStore(t))
+    if (valsGetAll.length !== 2) {
+      logging.fail('getAll does not return two values')
+    }
+    const valsIterate = []
+    const keyrange = idb.createIDBKeyRangeBound(['t', 0], ['t', 1], false, false)
+    await idb.put(getStore(t), 2, ['t', 2])
+    await idb.iterate(getStore(t), keyrange, (val, key) => {
+      valsIterate.push(val)
+    })
+    if (valsIterate.length !== 2) {
+      logging.fail('iterate does not return two values')
+    }
+  })
+})

lib/logging.js

@@ -0,0 +1,23 @@
+
+import * as globals from './globals.js'
+
+let date = new Date().getTime()
+
+const writeDate = () => {
+  const oldDate = date
+  date = new Date().getTime()
+  return date - oldDate
+}
+
+export const print = (...args) => console.log(...args)
+export const log = m => print(`%cydb-client: %c${m} %c+${writeDate()}ms`, 'color: blue;', '', 'color: blue')
+
+export const fail = m => {
+  throw new Error(m)
+}
+
+/**
+ * @param {ArrayBuffer} buffer
+ * @return {string}
+ */
+export const arrayBufferToString = buffer => JSON.stringify(Array.from(globals.createUint8ArrayFromBuffer(buffer)))

lib/mutualExclude.js

@@ -0,0 +1,34 @@
+// TODO: rename mutex
+
+/**
+ * Creates a mutual exclude function with the following property:
+ *
+ * @example
+ * const mutualExclude = createMutualExclude()
+ * mutualExclude(function () {
+ *   // This function is immediately executed
+ *   mutualExclude(function () {
+ *     // This function is never executed, as it is called with the same
+ *     // mutualExclude
+ *   })
+ * })
+ *
+ * @return {Function} A mutual exclude function
+ * @public
+ */
+export function createMutualExclude () {
+  var token = true
+  return function mutualExclude (f, g) {
+    if (token) {
+      token = false
+      try {
+        f()
+      } catch (e) {
+        console.error(e)
+      }
+      token = true
+    } else if (g !== undefined) {
+      g()
+    }
+  }
+}

lib/simpleDiff.js

@@ -0,0 +1,47 @@
+
+/**
+ * A SimpleDiff describes a change on a String.
+ *
+ * @example
+ * console.log(a) // the old value
+ * console.log(b) // the updated value
+ * // Apply changes of diff (pseudocode)
+ * a.remove(diff.pos, diff.remove) // Remove `diff.remove` characters
+ * a.insert(diff.pos, diff.insert) // Insert `diff.insert`
+ * a === b // values match
+ *
+ * @typedef {Object} SimpleDiff
+ * @property {Number} pos The index where changes were applied
+ * @property {Number} remove The number of characters to delete starting
+ *                                  at `index`.
+ * @property {String} insert The new text to insert at `index` after applying
+ *                           `delete`
+ */
+
+/**
+ * Create a diff between two strings. This diff implementation is highly
+ * efficient, but not very sophisticated.
+ *
+ * @public
+ * @param {String} a The old version of the string
+ * @param {String} b The updated version of the string
+ * @return {SimpleDiff} The diff description.
+ */
+export default function simpleDiff (a, b) {
+  let left = 0 // number of same characters counting from left
+  let right = 0 // number of same characters counting from right
+  while (left < a.length && left < b.length && a[left] === b[left]) {
+    left++
+  }
+  if (left !== a.length || left !== b.length) {
+    // Only check right if a !== b
+    while (right + left < a.length && right + left < b.length && a[a.length - right - 1] === b[b.length - right - 1]) {
+      right++
+    }
+  }
+  return {
+    pos: left, // TODO: rename to index (also in type above)
+    remove: a.length - left - right,
+    insert: b.slice(left, b.length - right)
+  }
+}

lib/test.js

@@ -0,0 +1,33 @@
+import * as logging from './logging.js'
+import simpleDiff from './simpleDiff.js'
+
+export const run = async (name, f) => {
+  console.log(`%cStart:%c   ${name}`, 'color:blue;', '')
+  const start = new Date()
+  try {
+    await f(name)
+  } catch (e) {
+    logging.print(`%cFailure:%c ${name} in %c${new Date().getTime() - start.getTime()}ms`, 'color:red;font-weight:bold', '', 'color:grey')
+    throw e
+  }
+  logging.print(`%cSuccess:%c ${name} in %c${new Date().getTime() - start.getTime()}ms`, 'color:green;font-weight:bold', '', 'color:grey')
+}
+
+export const compareArrays = (as, bs) => {
+  if (as.length !== bs.length) {
+    return false
+  }
+  for (let i = 0; i < as.length; i++) {
+    if (as[i] !== bs[i]) {
+      return false
+    }
+  }
+  return true
+}
+
+export const compareStrings = (a, b) => {
+  if (a !== b) {
+    const diff = simpleDiff(a, b)
+    logging.print(`%c${a.slice(0, diff.pos)}%c${a.slice(diff.pos, diff.remove)}%c${diff.insert}%c${a.slice(diff.pos + diff.remove)}`, 'color:grey', 'color:red', 'color:green', 'color:grey')
+  }
+}