Validate incoming JS Message Headers: test message parser

mojo/public/js/bindings/tests/validation_test_input_parser.js

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Support for parsing binary sequences encoded as readable strings
+// or ".data" files. The input format is described here:
+// mojo/public/cpp/bindings/tests/validation_test_input_parser.h
+
+define([
+    "mojo/public/js/bindings/buffer"
+  ], function(buffer) {
+
+  // Files and Lines represent the raw text from an input string
+  // or ".data" file.
+
+  function InputError(message, line) {
+    this.message = message;
+    this.line = line;
+  }
+
+  InputError.prototype.toString = function() {
+    var s = 'Error: ' + this.message;
+    if (this.line)
+      s += ', at line ' +
+           (this.line.number + 1) + ': "' + this.line.contents + '"';
+    return s;
+  }
+
+  function File(contents) {
+    this.contents = contents;
+    this.index = 0;
+    this.lineNumber = 0;
+  }
+
+  File.prototype.endReached = function() {
+    return this.index >= this.contents.length;
+  }
+
+  File.prototype.nextLine = function() {
+    if (this.endReached())
+      return null;
+    var start = this.index;
+    var end = this.contents.indexOf('\n', start);
+    if (end == -1)
+      end = this.contents.length;
+    this.index = end + 1;
+    return new Line(this.contents.substring(start, end), this.lineNumber++);
+  }
+
+  function Line(contents, number) {
+    var i = contents.indexOf('//');
+    var s = (i == -1) ? contents.trim() : contents.substring(0, i).trim();
+    this.contents = contents;
+    this.items = (s.length > 0) ? s.split(/\s+/) : [];
+    this.index = 0;
+    this.number = number;
+  }
+
+  Line.prototype.endReached = function() {
+    return this.index >= this.items.length;
+  }
+
+  var ITEM_TYPE_SIZES = {
+    u1: 1, u2: 2, u4: 4, u8: 8, s1: 1, s2: 2, s4: 4, s8: 8, b: 1, f: 4, d: 8,
+    dist4: 4, dist8: 8, anchr: 0, handles: 0
+  };
+
+  function isValidItemType(type) {
+    return ITEM_TYPE_SIZES[type] !== undefined;
+  }
+
+  Line.prototype.nextItem = function() {
+    if (this.endReached())
+      return null;
+
+    var itemString = this.items[this.index++];
+    var type = 'u1';
+    var value = itemString;
+
+    if (itemString.charAt(0) == '[') {
+      var i = itemString.indexOf(']');
+      if (i != -1 && i + 1 < itemString.length) {
+        type = itemString.substring(1, i);
+        value = itemString.substring(i + 1);
+      } else {
+        throw new InputError('invalid item', this);
+      }
+    }
+    if (!isValidItemType(type))
+      throw new InputError('invalid item type', this);
+
+    return new Item(this, type, value);
+  }
+
+  // The text for each whitespace delimited binary data "item"

[yzshen1, 2014/07/24 01:15:10]

nit: please fill the line as close to 80 chars as possible.

+  // is represented by an Item.
+
+  function Item(line, type, value) {
+    this.line = line;
+    this.type = type;
+    this.value = value;
+    this.size = ITEM_TYPE_SIZES[type];
+  }
+
+  Item.prototype.isFloat = function() {
+    return this.type == 'f' || this.type == 'd';
+  }
+
+  Item.prototype.isInteger = function() {
+    return ['u1', 'u2', 'u4', 'u8',
+            's1', 's2', 's4', 's8'].indexOf(this.type) != -1;
+  }
+
+  Item.prototype.isNumber = function() {
+    return this.isFloat() || this.isInteger();
+  }
+
+  Item.prototype.isByte = function() {
+    return this.type == 'b';
+  }
+
+  Item.prototype.isDistance = function() {
+    return this.type == 'dist4' || this.type == 'dist8';
+  }
+
+  Item.prototype.isAnchor = function() {
+    return this.type == 'anchr';
+  }
+
+  Item.prototype.isHandles = function() {
+    return this.type == 'handles';
+  }
+
+  // A TestMessage represents the complete binary message loaded from
+  // an input string or ".data" file. The parseTestMessage() function
+  // below constructs a TestMessage from a File.
+
+  function TestMessage(byteLength) {
+    this.index = 0;
+    this.buffer = new buffer.Buffer(byteLength);
+    this.distances = {};
+    this.handleCount = 0;
+  }
+
+  function checkItemNumberValue(item, n, min, max) {
+    if (n < min || n > max)
+      throw new InputError('invalid item value', item.line);
+  }
+
+  TestMessage.prototype.addNumber = function(item) {
+    var n = item.isInteger() ? parseInt(item.value) : parseFloat(item.value);
+    if (Number.isNaN(n))
+      throw new InputError("can't parse item value", item.line);
+
+    switch(item.type) {
+      case 'u1':
+        checkItemNumberValue(item, n, 0, 0xFF);
+        this.buffer.setUint8(this.index, n);
+        break;
+      case 'u2':
+        checkItemNumberValue(item, n, 0, 0xFFFF);
+        this.buffer.setUint16(this.index, n);
+        break;
+      case 'u4':
+        checkItemNumberValue(item, n, 0, 0xFFFFFFFF);
+        this.buffer.setUint32(this.index, n);
+        break;
+      case 'u8':
+        checkItemNumberValue(item, n, 0, Number.MAX_SAFE_INTEGER);
+        this.buffer.setUint64(this.index, n);
+        break;
+      case 's1':
+        checkItemNumberValue(item, n, -128, 127);
+        this.buffer.setInt8(this.index, n);
+        break;
+      case 's2':
+        checkItemNumberValue(item, n, -32768, 32767);
+        this.buffer.setInt16(this.index, n);
+        break;
+      case 's4':
+        checkItemNumberValue(item, n, -2147483648, 2147483647);
+        this.buffer.setInt32(this.index, n);
+        break;
+      case 's8':
+        checkItemNumberValue(item, n,
+                             Number.MIN_SAFE_INTEGER,
+                             Number.MAX_SAFE_INTEGER);
+        this.buffer.setInt64(this.index, n);
+        break;
+      case 'f':
+        this.buffer.setFloat32(this.index, n);
+        break;
+      case 'd':
+        this.buffer.setFloat64(this.index, n);
+        break;
+
+      default:
+        throw new InputError('unrecognized item type', item.line);
+      }
+  }
+
+  TestMessage.prototype.addByte = function(item) {
+    if (!/^[01]{8}$/.test(item.value))
+      throw new InputError('invalid byte item value', item.line);
+    function b(i) {
+      return (item.value.charAt(7 - i) == '1') ? 1 << i : 0;
+    }
+    var n = b(0) | b(1) | b(2) | b(3) | b(4) | b(5) | b(6) | b(7);
+    this.buffer.setUint8(this.index, n);
+  }
+
+  TestMessage.prototype.addDistance = function(item) {
+    if (this.distances[item.value])
+      throw new InputError('duplicate distance item', item.line);
+    this.distances[item.value] = {index: this.index, item: item};
+  }
+
+  TestMessage.prototype.addAnchor = function(item) {
+    var dist = this.distances[item.value];
+    if (!dist)
+      throw new InputError('unmatched anchor item', item.line);
+    delete this.distances[item.value];
+
+    var n = this.index - dist.index;
+    // TODO(hansmuller): validate n
+
+    if (dist.item.type == 'dist4')
+      this.buffer.setUint32(dist.index, n);
+    else if (dist.item.type == 'dist8')
+      this.buffer.setUint64(dist.index, n);
+    else
+      throw new InputError('unrecognzed distance item type', dist.item.line);
+  }
+
+  TestMessage.prototype.addHandles = function(item) {
+    this.handleCount = parseInt(item.value);
+    if (Number.isNaN(this.handleCount))
+      throw new InputError("can't parse handleCount", item.line);
+  }
+
+  TestMessage.prototype.addItem = function(item) {
+    if (item.isNumber())
+      this.addNumber(item);
+    else if (item.isByte())
+      this.addByte(item);
+    else if (item.isDistance())
+      this.addDistance(item);
+    else if (item.isAnchor())
+      this.addAnchor(item);
+    else if (item.isHandles())
+      this.addHandles(item);
+    else
+      throw new InputError('unrecognized item type', item.line);
+
+    this.index += item.size;
+  }
+
+  TestMessage.prototype.unanchoredDistances = function() {
+    var names = null;
+    for (var name in this.distances) {
+      if (this.distances.hasOwnProperty(name))
+        names = (names === null) ? name : names + ' ' + name;
+    }
+    return names;
+  }
+
+  function parseTestMessage(text) {
+    var file = new File(text);
+    var items = [];
+    var messageLength = 0;
+    while(!file.endReached()) {
+      var line = file.nextLine();
+      while (!line.endReached()) {
+        var item = line.nextItem();
+        if (item.isHandles() && items.length > 0)
+          throw new InputError('handles item is not first');
+        messageLength += item.size;
+        items.push(item);
+      }
+    }
+
+    var msg = new TestMessage(messageLength);
+    for (var i = 0; i < items.length; i++)
+      msg.addItem(items[i]);
+
+    if (messageLength != msg.index)
+      throw new InputError('failed to compute message length');
+    var names = msg.unanchoredDistances();
+    if (names)
+      throw new InputError('no anchors for ' + names, 0);
+
+    return msg;
+  }
+
+  var exports = {};
+  exports.parseTestMessage = parseTestMessage;
+  exports.InputError = InputError;
+  return exports;
+});