Add third_party/google-input-tools: Take 2

third_party/google_input_tools/src/chrome/os/keyboard/model.js

+// Copyright 2014 The ChromeOS IME Authors. All Rights Reserved.
+// limitations under the License.
+// See the License for the specific language governing permissions and
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// distributed under the License is distributed on an "AS-IS" BASIS,
+// Unless required by applicable law or agreed to in writing, software
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// You may obtain a copy of the License at
+// you may not use this file except in compliance with the License.
+// Licensed under the Apache License, Version 2.0 (the "License");
+//
+// Copyright 2013 The ChromeOS VK Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS-IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+/**
+ * @fileoverview Definition of Model class.
+ *     It is responsible for dynamically loading the layout JS files. It
+ *     interprets the layout info and provides the function of getting
+ *     transformed chars and recording history states to Model.
+ *     It notifies View via events when layout info changes.
+ *     This is the Model of MVC pattern.
+ */
+
+goog.provide('i18n.input.chrome.vk.Model');
+
+goog.require('goog.events.EventTarget');
+goog.require('goog.net.jsloader');
+goog.require('goog.object');
+goog.require('goog.string');
+goog.require('i18n.input.chrome.vk.EventType');
+goog.require('i18n.input.chrome.vk.LayoutEvent');
+goog.require('i18n.input.chrome.vk.ParsedLayout');
+
+
+
+/**
+ * Creates the Model object.
+ *
+ * @constructor
+ * @extends {goog.events.EventTarget}
+ */
+i18n.input.chrome.vk.Model = function() {
+  goog.base(this);
+
+  /**
+   * The registered layouts object.
+   * Its format is {<layout code>: <parsed layout obj>}.
+   *
+   * @type {!Object.<!i18n.input.chrome.vk.ParsedLayout|boolean>}
+   * @private
+   */
+  this.layouts_ = {};
+
+  /**
+   * The active layout code.
+   *
+   * @type {string}
+   * @private
+   */
+  this.activeLayout_ = '';
+
+  /**
+   * The layout code of which the layout is "being activated" when the layout
+   * hasn't been loaded yet.
+   *
+   * @type {string}
+   * @private
+   */
+  this.delayActiveLayout_ = '';
+
+  /**
+   * History state used for ambiguous transforms.
+   *
+   * @type {!Object}
+   * @private
+   */
+  this.historyState_ = {
+    previous: {text: '', transat: -1},
+    ambi: '',
+    current: {text: '', transat: -1}
+  };
+
+  // Exponses the onLayoutLoaded so that the layout JS can call it back.
+  goog.exportSymbol('cros_vk_loadme', goog.bind(this.onLayoutLoaded_, this));
+};
+goog.inherits(i18n.input.chrome.vk.Model, goog.events.EventTarget);
+
+
+/**
+ * Loads the layout in the background.
+ *
+ * @param {string} layoutCode The layout will be loaded.
+ */
+i18n.input.chrome.vk.Model.prototype.loadLayout = function(layoutCode) {
+  if (!layoutCode) return;
+
+  var parsedLayout = this.layouts_[layoutCode];
+  // The layout is undefined means not loaded, false means loading.
+  if (parsedLayout == undefined) {
+    this.layouts_[layoutCode] = false;
+    i18n.input.chrome.vk.Model.loadLayoutScript_(layoutCode);
+  } else if (parsedLayout) {
+    this.dispatchEvent(new i18n.input.chrome.vk.LayoutEvent(
+        i18n.input.chrome.vk.EventType.LAYOUT_LOADED,
+        /** @type {!Object} */ (parsedLayout)));
+  }
+};
+
+
+/**
+ * Activate layout by setting the current layout.
+ *
+ * @param {string} layoutCode The layout will be set as current layout.
+ */
+i18n.input.chrome.vk.Model.prototype.activateLayout = function(
+    layoutCode) {
+  if (!layoutCode) return;
+
+  if (this.activeLayout_ != layoutCode) {
+    var parsedLayout = this.layouts_[layoutCode];
+    if (parsedLayout) {
+      this.activeLayout_ = layoutCode;
+      this.delayActiveLayout_ = '';
+      this.clearHistory();
+    } else if (parsedLayout == false) { // Layout being loaded?
+      this.delayActiveLayout_ = layoutCode;
+    }
+  }
+};
+
+
+/**
+ * Gets the current layout.
+ *
+ * @return {string} The current layout code.
+ */
+i18n.input.chrome.vk.Model.prototype.getCurrentLayout = function() {
+  return this.activeLayout_;
+};
+
+
+/**
+ * Predicts whether there would be future transforms for the history text.
+ *
+ * @return {number} The matched position. Returns -1 for no match.
+ */
+i18n.input.chrome.vk.Model.prototype.predictHistory = function() {
+  if (!this.activeLayout_ || !this.layouts_[this.activeLayout_]) {
+    return -1;
+  }
+  var parsedLayout = this.layouts_[this.activeLayout_];
+  var history = this.historyState_;
+  var text, transat;
+  if (history.ambi) {
+    text = history.previous.text;
+    transat = history.previous.transat;
+    // Tries to predict transform for previous history.
+    if (transat > 0) {
+      text = text.slice(0, transat) + '\u001d' + text.slice(transat) +
+          history.ambi;
+    } else {
+      text += history.ambi;
+    }
+    if (parsedLayout.predictTransform(text) >= 0) {
+      // If matched previous history, always return 0 because outside will use
+      // this to keep the composition text.
+      return 0;
+    }
+  }
+  // Tries to predict transform for current history.
+  text = history.current.text;
+  transat = history.current.transat;
+  if (transat >= 0) {
+    text = text.slice(0, transat) + '\u001d' + text.slice(transat);
+  }
+  var pos = parsedLayout.predictTransform(text);
+  if (transat >= 0 && pos > transat) {
+    // Adjusts the pos for removing the temporary \u001d character.
+    pos--;
+  }
+  return pos;
+};
+
+
+/**
+ * Translates the key code into the chars to put into the active input box.
+ *
+ * @param {string} chars The key commit chars.
+ * @param {string} charsBeforeCaret The chars before the caret in the active
+ *     input box. This will be used to compare with the history states.
+ * @return {Object} The replace chars object whose 'back' means delete how many
+ *     chars back from the caret, and 'chars' means the string insert after the
+ *     deletion. Returns null if no result.
+ */
+i18n.input.chrome.vk.Model.prototype.translate = function(
+    chars, charsBeforeCaret) {
+  if (!this.activeLayout_ || !chars) {
+    return null;
+  }
+  var parsedLayout = this.layouts_[this.activeLayout_];
+  if (!parsedLayout) {
+    return null;
+  }
+
+  this.matchHistory_(charsBeforeCaret);
+  var result, history = this.historyState_;
+  if (history.ambi) {
+    // If ambi is not empty, it means some ambi chars has been typed
+    // before. e.g. ka->k, kaa->K, typed 'ka', and now typing 'a':
+    //   history.previous == 'k',1
+    //   history.current == 'k',1
+    //   history.ambi == 'a'
+    // So now we should get transform of 'k\u001d' + 'aa'.
+    result = parsedLayout.transform(
+        history.previous.text, history.previous.transat,
+        history.ambi + chars);
+    // Note: result.back could be negative number. In such case, we should give
+    // up the transform result. This is to be compatible the old vk behaviors.
+    if (result && result.back < 0) {
+      result = null;
+    }
+  }
+  if (result) {
+    // Because the result is related to previous history, adjust the result so
+    // that it is related to current history.
+    var prev = history.previous.text;
+    prev = prev.slice(0, prev.length - result.back);
+    prev += result.chars;
+    result.back = history.current.text.length;
+    result.chars = prev;
+  } else {
+    // If no ambi chars or no transforms for ambi chars, try to match the
+    // regular transforms. In above case, if now typing 'b', we should get
+    // transform of 'k\u001d' + 'b'.
+    result = parsedLayout.transform(
+        history.current.text, history.current.transat, chars);
+  }
+  // Updates the history state.
+  if (parsedLayout.isAmbiChars(history.ambi + chars)) {
+    if (!history.ambi) {
+      // Empty ambi means chars should be the first ambi chars.
+      // So now we should set the previous.
+      history.previous = goog.object.clone(history.current);
+    }
+    history.ambi += chars;
+  } else if (parsedLayout.isAmbiChars(chars)) {
+    // chars could match ambi regex when ambi+chars cannot.
+    // In this case, record the current history to previous, and set ambi as
+    // chars.
+    history.previous = goog.object.clone(history.current);
+    history.ambi = chars;
+  } else {
+    history.previous.text = '';
+    history.previous.transat = -1;
+    history.ambi = '';
+  }
+  // Updates the history text per transform result.
+  var text = history.current.text;
+  var transat = history.current.transat;
+  if (result) {
+    text = text.slice(0, text.length - result.back);
+    text += result.chars;
+    transat = text.length;
+  } else {
+    text += chars;
+    // This function doesn't return null. So if result is null, fill it.
+    result = {back: 0, chars: chars};
+  }
+  // The history text cannot cannot contain SPACE!
+  var spacePos = text.lastIndexOf(' ');
+  if (spacePos >= 0) {
+    text = text.slice(spacePos + 1);
+    if (transat > spacePos) {
+      transat -= spacePos + 1;
+    } else {
+      transat = -1;
+    }
+  }
+  history.current.text = text;
+  history.current.transat = transat;
+
+  return result;
+};
+
+
+/**
+ * Wether the active layout has transforms defined.
+ *
+ * @return {boolean} True if transforms defined, false otherwise.
+ */
+i18n.input.chrome.vk.Model.prototype.hasTransforms = function() {
+  var parsedLayout = this.layouts_[this.activeLayout_];
+  return !!parsedLayout && !!parsedLayout.transforms;
+};
+
+
+/**
+ * Processes the backspace key. It affects the history state.
+ *
+ * @param {string} charsBeforeCaret The chars before the caret in the active
+ *     input box. This will be used to compare with the history states.
+ */
+i18n.input.chrome.vk.Model.prototype.processBackspace = function(
+    charsBeforeCaret) {
+  this.matchHistory_(charsBeforeCaret);
+
+  var history = this.historyState_;
+  // Reverts the current history. If the backspace across over the transat pos,
+  // clean it up.
+  var text = history.current.text;
+  if (text) {
+    text = text.slice(0, text.length - 1);
+    history.current.text = text;
+    if (history.current.transat > text.length) {
+      history.current.transat = text.length;
+    }
+
+    text = history.ambi;
+    if (text) { // If there is ambi text, remove the last char in ambi.
+      history.ambi = text.slice(0, text.length - 1);
+    }
+    // Prev history only exists when ambi is not empty.
+    if (!history.ambi) {
+      history.previous = {text: '', transat: -1};
+    }
+  } else {
+    // Cleans up the previous history.
+    history.previous = {text: '', transat: -1};
+    history.ambi = '';
+    // Cleans up the current history.
+    history.current = goog.object.clone(history.previous);
+  }
+};
+
+
+/**
+ * Callback when layout loaded.
+ *
+ * @param {!Object} layout The layout object passed from the layout JS's loadme
+ *     callback.
+ * @private
+ */
+i18n.input.chrome.vk.Model.prototype.onLayoutLoaded_ = function(layout) {
+  var parsedLayout = new i18n.input.chrome.vk.ParsedLayout(layout);
+  if (parsedLayout.id) {
+    this.layouts_[parsedLayout.id] = parsedLayout;
+  }
+  if (this.delayActiveLayout_ == layout.id) {
+    this.activateLayout(this.delayActiveLayout_);
+    this.delayActiveLayout_ = '';
+  }
+  this.dispatchEvent(new i18n.input.chrome.vk.LayoutEvent(
+      i18n.input.chrome.vk.EventType.LAYOUT_LOADED, parsedLayout));
+};
+
+
+/**
+ * Matches the given text to the last transformed text. Clears history if they
+ * are not matched.
+ *
+ * @param {string} text The text to be matched.
+ * @private
+ */
+i18n.input.chrome.vk.Model.prototype.matchHistory_ = function(text) {
+  var hisText = this.historyState_.current.text;
+  if (!hisText || !text || !(goog.string.endsWith(text, hisText) ||
+      goog.string.endsWith(hisText, text))) {
+    this.clearHistory();
+  }
+};
+
+
+/**
+ * Clears the history state.
+ */
+i18n.input.chrome.vk.Model.prototype.clearHistory = function() {
+  this.historyState_.ambi = '';
+  this.historyState_.previous = {text: '', transat: -1};
+  this.historyState_.current = goog.object.clone(this.historyState_.previous);
+};
+
+
+/**
+ * Prunes the history state to remove a number of chars at beginning.
+ *
+ * @param {number} count The count of chars to be removed.
+ */
+i18n.input.chrome.vk.Model.prototype.pruneHistory = function(count) {
+  var pruneFunc = function(his) {
+    his.text = his.text.slice(count);
+    if (his.transat > 0) {
+      his.transat -= count;
+      if (his.transat <= 0) {
+        his.transat = -1;
+      }
+    }
+  };
+  pruneFunc(this.historyState_.previous);
+  pruneFunc(this.historyState_.current);
+};
+
+
+/**
+ * Loads the script for a layout.
+ *
+ * @param {string} layoutCode The layout code.
+ * @private
+ */
+i18n.input.chrome.vk.Model.loadLayoutScript_ = function(layoutCode) {
+  goog.net.jsloader.load('layouts/' + layoutCode + '.js');
+};