chrome/browser/resources/local_ntp/most_visited_single.js

/* Copyright 2015 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. */

 // Single iframe for NTP tiles.
(function() {
'use strict';


/**
 * The different types of events that are logged from the NTP.  This enum is
 * used to transfer information from the NTP JavaScript to the renderer and is
 * not used as a UMA enum histogram's logged value.
 * Note: Keep in sync with common/ntp_logging_events.h
 * @enum {number}
 * @const
 */
var LOG_TYPE = {
  // All NTP Tiles have finished loading (successfully or failing).
  NTP_ALL_TILES_LOADED: 11,
};


/**
 * The different sources that an NTP tile can have.
 * Note: Keep in sync with common/ntp_logging_events.h
 * @enum {number}
 * @const
 */
var NTPLoggingTileSource = {
  CLIENT: 0,
  SERVER: 1,
};


/**
 * Total number of tiles to show at any time. If the host page doesn't send
 * enough tiles, we fill them blank.
 * @const {number}
 */
var NUMBER_OF_TILES = 8;


/**
 * Whether to use icons instead of thumbnails.
 * @type {boolean}
 */
var USE_ICONS = false;


/**
 * Number of lines to display in titles.
 * @type {number}
 */
var NUM_TITLE_LINES = 1;


/**
 * The origin of this request.
 * @const {string}
 */
var DOMAIN_ORIGIN = '{{ORIGIN}}';


/**
 * Counter for DOM elements that we are waiting to finish loading.
 * @type {number}
 */
var loadedCounter = 1;


/**
 * DOM element containing the tiles we are going to present next.
 * Works as a double-buffer that is shown when we receive a "show" postMessage.
 * @type {Element}
 */
var tiles = null;


/**
 * List of parameters passed by query args.
 * @type {Object}
 */
var queryArgs = {};

/**
 * Url to ping when suggestions have been shown.
 */
var impressionUrl = null;


/**
 * Log an event on the NTP.
 * @param {number} eventType Event from LOG_TYPE.
 */
var logEvent = function(eventType) {
  chrome.embeddedSearch.newTabPage.logEvent(eventType);
};

/**
 * Log impression of an NTP tile.
 * @param {number} tileIndex Position of the tile, >= 0 and < NUMBER_OF_TILES.
 * @param {number} tileSource The source from NTPLoggingTileSource.
 */
function logMostVisitedImpression(tileIndex, tileSource) {
  chrome.embeddedSearch.newTabPage.logMostVisitedImpression(tileIndex,
                                                            tileSource);
}

/**
 * Log click on an NTP tile.
 * @param {number} tileIndex Position of the tile, >= 0 and < NUMBER_OF_TILES.
 * @param {number} tileSource The source from NTPLoggingTileSource.
 */
function logMostVisitedNavigation(tileIndex, tileSource) {
  chrome.embeddedSearch.newTabPage.logMostVisitedNavigation(tileIndex,
                                                            tileSource);
}

/**
 * Down counts the DOM elements that we are waiting for the page to load.
 * When we get to 0, we send a message to the parent window.
 * This is usually used as an EventListener of onload/onerror.
 */
var countLoad = function() {
  loadedCounter -= 1;
  if (loadedCounter <= 0) {
    showTiles();
    logEvent(LOG_TYPE.NTP_ALL_TILES_LOADED);
    window.parent.postMessage({cmd: 'loaded'}, DOMAIN_ORIGIN);
    loadedCounter = 1;
  }
};


/**
 * Handles postMessages coming from the host page to the iframe.
 * Mostly, it dispatches every command to handleCommand.
 */
var handlePostMessage = function(event) {
  if (event.data instanceof Array) {
    for (var i = 0; i < event.data.length; ++i) {
      handleCommand(event.data[i]);
    }
  } else {
    handleCommand(event.data);
  }
};


/**
 * Handles a single command coming from the host page to the iframe.
 * We try to keep the logic here to a minimum and just dispatch to the relevant
 * functions.
 */
var handleCommand = function(data) {
  var cmd = data.cmd;

  if (cmd == 'tile') {
    addTile(data);
  } else if (cmd == 'show') {
    countLoad();
    hideOverflowTiles(data);
  } else if (cmd == 'updateTheme') {
    updateTheme(data);
  } else if (cmd == 'tilesVisible') {
    hideOverflowTiles(data);
  } else {
    console.error('Unknown command: ' + JSON.stringify(data));
  }
};


var updateTheme = function(info) {
  var themeStyle = [];

  if (info.tileBorderColor) {
    themeStyle.push('.thumb-ntp .mv-tile {' +
        'border: 1px solid ' + info.tileBorderColor + '; }');
  }
  if (info.tileHoverBorderColor) {
    themeStyle.push('.thumb-ntp .mv-tile:hover {' +
        'border-color: ' + info.tileHoverBorderColor + '; }');
  }
  if (info.isThemeDark) {
    themeStyle.push('.thumb-ntp .mv-tile, .thumb-ntp .mv-empty-tile { ' +
        'background: rgb(51,51,51); }');
    themeStyle.push('.thumb-ntp .mv-thumb.failed-img { ' +
        'background-color: #555; }');
    themeStyle.push('.thumb-ntp .mv-thumb.failed-img::after { ' +
        'border-color: #333; }');
    themeStyle.push('.thumb-ntp .mv-x { ' +
        'background: linear-gradient(to left, ' +
        'rgb(51,51,51) 60%, transparent); }');
    themeStyle.push('html[dir=rtl] .thumb-ntp .mv-x { ' +
        'background: linear-gradient(to right, ' +
        'rgb(51,51,51) 60%, transparent); }');
    themeStyle.push('.thumb-ntp .mv-x::after { ' +
        'background-color: rgba(255,255,255,0.7); }');
    themeStyle.push('.thumb-ntp .mv-x:hover::after { ' +
        'background-color: #fff; }');
    themeStyle.push('.thumb-ntp .mv-x:active::after { ' +
        'background-color: rgba(255,255,255,0.5); }');
    themeStyle.push('.icon-ntp .mv-tile:focus { ' +
        'background: rgba(255,255,255,0.2); }');
  }
  if (info.tileTitleColor) {
    themeStyle.push('body { color: ' + info.tileTitleColor + '; }');
  }

  document.querySelector('#custom-theme').textContent = themeStyle.join('\n');
};


/**
 * Hides extra tiles that don't fit on screen.
 */
var hideOverflowTiles = function(data) {
  var tileAndEmptyTileList = document.querySelectorAll(
      '#mv-tiles .mv-tile,#mv-tiles .mv-empty-tile');
  for (var i = 0; i < tileAndEmptyTileList.length; ++i) {
    tileAndEmptyTileList[i].classList.toggle('hidden', i >= data.maxVisible);
  }
};


/**
 * Removes all old instances of #mv-tiles that are pending for deletion.
 */
var removeAllOldTiles = function() {
  var parent = document.querySelector('#most-visited');
  var oldList = parent.querySelectorAll('.mv-tiles-old');
  for (var i = 0; i < oldList.length; ++i) {
    parent.removeChild(oldList[i]);
  }
};


/**
 * Called when the host page has finished sending us tile information and
 * we are ready to show the new tiles and drop the old ones.
 */
var showTiles = function() {
  // Store the tiles on the current closure.
  var cur = tiles;

  // Create empty tiles until we have NUMBER_OF_TILES.
  while (cur.childNodes.length < NUMBER_OF_TILES) {
    addTile({});
  }

  var parent = document.querySelector('#most-visited');

  // Only fade in the new tiles if there were tiles before.
  var fadeIn = false;
  var old = parent.querySelector('#mv-tiles');
  if (old) {
    fadeIn = true;
    // Mark old tile DIV for removal after the transition animation is done.
    old.removeAttribute('id');
    old.classList.add('mv-tiles-old');
    old.style.opacity = 0.0;
    cur.addEventListener('webkitTransitionEnd', function(ev) {
      if (ev.target === cur) {
        removeAllOldTiles();
      }
    });
  }

  // Add new tileset.
  cur.id = 'mv-tiles';
  parent.appendChild(cur);
  // getComputedStyle causes the initial style (opacity 0) to be applied, so
  // that when we then set it to 1, that triggers the CSS transition.
  if (fadeIn) {
    window.getComputedStyle(cur).opacity;
  }
  cur.style.opacity = 1.0;

  // Make sure the tiles variable contain the next tileset we may use.
  tiles = document.createElement('div');

  if (impressionUrl) {
    navigator.sendBeacon(impressionUrl);
    impressionUrl = null;
  }
};


/**
 * Called when the host page wants to add a suggestion tile.
 * For Most Visited, it grabs the data from Chrome and pass on.
 * For host page generated it just passes the data.
 * @param {object} args Data for the tile to be rendered.
 */
var addTile = function(args) {
  if (isFinite(args.rid)) {
    // If a valid number passed in |args.rid|: a local chrome suggestion.
    var data = chrome.embeddedSearch.searchBox.getMostVisitedItemData(args.rid);
    if (!data)
      return;

    data.tid = data.rid;
    data.tileSource = NTPLoggingTileSource.CLIENT;
    if (!data.faviconUrl) {
      data.faviconUrl = 'chrome-search://favicon/size/16@' +
          window.devicePixelRatio + 'x/' + data.renderViewId + '/' + data.tid;
    }
    tiles.appendChild(renderTile(data));
  } else if (args.url) {
    // If a URL is passed: a server-side suggestion.
    args.tileSource = NTPLoggingTileSource.SERVER;
    // check sanity of the arguments
    if (/^javascript:/i.test(args.url) ||
        /^javascript:/i.test(args.thumbnailUrl))
      return;
    tiles.appendChild(renderTile(args));
  } else {  // an empty tile
    tiles.appendChild(renderTile(null));
  }
};

/**
 * Called when the user decided to add a tile to the blacklist.
 * It sets of the animation for the blacklist and sends the blacklisted id
 * to the host page.
 * @param {Element} tile DOM node of the tile we want to remove.
 */
var blacklistTile = function(tile) {
  tile.classList.add('blacklisted');
  tile.addEventListener('webkitTransitionEnd', function(ev) {
    if (ev.propertyName != 'width') return;

    window.parent.postMessage({cmd: 'tileBlacklisted',
                               tid: Number(tile.getAttribute('data-tid'))},
                              DOMAIN_ORIGIN);
  });
};


/**
 * Returns whether the given URL has a known, safe scheme.
 * @param {string} url URL to check.
 */
var isSchemeAllowed = function(url) {
  return url.startsWith('http://') || url.startsWith('https://') ||
         url.startsWith('ftp://') || url.startsWith('file://') ||
         url.startsWith('chrome-extension://');
};


/**
 * Renders a MostVisited tile to the DOM.
 * @param {object} data Object containing rid, url, title, favicon, thumbnail.
 *     data is null if you want to construct an empty tile.
 */
var renderTile = function(data) {
  var tile = document.createElement('a');

  if (data == null) {
    tile.className = 'mv-empty-tile';
    return tile;
  }

  // The tile will be appended to tiles.
  var position = tiles.children.length;
  logMostVisitedImpression(position, data.tileSource);

  tile.className = 'mv-tile';
  tile.setAttribute('data-tid', data.tid);
  var html = [];
  if (!USE_ICONS) {
    html.push('<div class="mv-favicon"></div>');
  }
  html.push('<div class="mv-title"></div><div class="mv-thumb"></div>');
  html.push('<div class="mv-x" role="button"></div>');
  tile.innerHTML = html.join('');
  tile.lastElementChild.title = queryArgs['removeTooltip'] || '';

  if (isSchemeAllowed(data.url)) {
    tile.href = data.url;
  }
  tile.setAttribute('aria-label', data.title);
  tile.title = data.title;
  if (data.impressionUrl) {
    impressionUrl = data.impressionUrl;
  }
  if (data.pingUrl) {
    tile.addEventListener('click', function(ev) {
      navigator.sendBeacon(data.pingUrl);
    });
  }

  tile.addEventListener('click', function(ev) {
    logMostVisitedNavigation(position, data.tileSource);
  });

  tile.addEventListener('keydown', function(event) {
    if (event.keyCode == 46 /* DELETE */ ||
        event.keyCode == 8 /* BACKSPACE */) {
      event.preventDefault();
      event.stopPropagation();
      blacklistTile(this);
    } else if (event.keyCode == 13 /* ENTER */ ||
               event.keyCode == 32 /* SPACE */) {
      event.preventDefault();
      this.click();
    } else if (event.keyCode >= 37 && event.keyCode <= 40 /* ARROWS */) {
      // specify the direction of movement
      var inArrowDirection = function(origin, target) {
        return (event.keyCode == 37 /* LEFT */ &&
                origin.offsetTop == target.offsetTop &&
                origin.offsetLeft > target.offsetLeft) ||
                (event.keyCode == 38 /* UP */ &&
                origin.offsetTop > target.offsetTop &&
                origin.offsetLeft == target.offsetLeft) ||
                (event.keyCode == 39 /* RIGHT */ &&
                origin.offsetTop == target.offsetTop &&
                origin.offsetLeft < target.offsetLeft) ||
                (event.keyCode == 40 /* DOWN */ &&
                origin.offsetTop < target.offsetTop &&
                origin.offsetLeft == target.offsetLeft);
      };

      var nonEmptyTiles = document.querySelectorAll('#mv-tiles .mv-tile');
      var nextTile = null;
      // Find the closest tile in the appropriate direction.
      for (var i = 0; i < nonEmptyTiles.length; i++) {
        if (inArrowDirection(this, nonEmptyTiles[i]) &&
            (!nextTile || inArrowDirection(nonEmptyTiles[i], nextTile))) {
          nextTile = nonEmptyTiles[i];
        }
      }
      if (nextTile) {
        nextTile.focus();
      }
    }
  });

  var title = tile.querySelector('.mv-title');
  title.innerText = data.title;
  title.style.direction = data.direction || 'ltr';
  if (NUM_TITLE_LINES > 1) {
    title.classList.add('multiline');
  }

  if (USE_ICONS) {
    var thumb = tile.querySelector('.mv-thumb');
    if (data.largeIconUrl) {
      var img = document.createElement('img');
      img.title = data.title;
      img.src = data.largeIconUrl;
      img.classList.add('large-icon');
      loadedCounter += 1;
      img.addEventListener('load', countLoad);
      img.addEventListener('load', function(ev) {
        thumb.classList.add('large-icon-outer');
      });
      img.addEventListener('error', countLoad);
      img.addEventListener('error', function(ev) {
        thumb.classList.add('failed-img');
        thumb.removeChild(img);
      });
      thumb.appendChild(img);
    } else {
      thumb.classList.add('failed-img');
    }
  } else { // THUMBNAILS
    // We keep track of the outcome of loading possible thumbnails for this
    // tile. Possible values:
    //   - null: waiting for load/error
    //   - false: error
    //   - a string: URL that loaded correctly.
    // This is populated by acceptImage/rejectImage and loadBestImage
    // decides the best one to load.
    var results = [];
    var thumb = tile.querySelector('.mv-thumb');
    var img = document.createElement('img');
    var loaded = false;

    var loadBestImage = function() {
      if (loaded) {
        return;
      }
      for (var i = 0; i < results.length; ++i) {
        if (results[i] === null) {
          return;
        }
        if (results[i] != false) {
          img.src = results[i];
          loaded = true;
          return;
        }
      }
      thumb.classList.add('failed-img');
      thumb.removeChild(img);
      countLoad();
    };

    var acceptImage = function(idx, url) {
      return function(ev) {
        results[idx] = url;
        loadBestImage();
      };
    };

    var rejectImage = function(idx) {
      return function(ev) {
        results[idx] = false;
        loadBestImage();
      };
    };

    img.title = data.title;
    img.classList.add('thumbnail');
    loadedCounter += 1;
    img.addEventListener('load', countLoad);
    img.addEventListener('error', countLoad);
    img.addEventListener('error', function(ev) {
      thumb.classList.add('failed-img');
      thumb.removeChild(img);
    });
    thumb.appendChild(img);

    if (data.thumbnailUrl) {
      img.src = data.thumbnailUrl;
    } else {
      // Get all thumbnailUrls for the tile.
      // They are ordered from best one to be used to worst.
      for (var i = 0; i < data.thumbnailUrls.length; ++i) {
        results.push(null);
      }
      for (var i = 0; i < data.thumbnailUrls.length; ++i) {
        if (data.thumbnailUrls[i]) {
          var image = new Image();
          image.src = data.thumbnailUrls[i];
          image.onload = acceptImage(i, data.thumbnailUrls[i]);
          image.onerror = rejectImage(i);
        } else {
          rejectImage(i)(null);
        }
      }
    }

    var favicon = tile.querySelector('.mv-favicon');
    if (data.faviconUrl) {
      var fi = document.createElement('img');
      fi.src = data.faviconUrl;
      // Set the title to empty so screen readers won't say the image name.
      fi.title = '';
      loadedCounter += 1;
      fi.addEventListener('load', countLoad);
      fi.addEventListener('error', countLoad);
      fi.addEventListener('error', function(ev) {
        favicon.classList.add('failed-favicon');
      });
      favicon.appendChild(fi);
    } else {
      favicon.classList.add('failed-favicon');
    }
  }

  var mvx = tile.querySelector('.mv-x');
  mvx.addEventListener('click', function(ev) {
    removeAllOldTiles();
    blacklistTile(tile);
    ev.preventDefault();
    ev.stopPropagation();
  });

  return tile;
};


/**
 * Do some initialization and parses the query arguments passed to the iframe.
 */
var init = function() {
  // Creates a new DOM element to hold the tiles.
  tiles = document.createElement('div');

  // Parse query arguments.
  var query = window.location.search.substring(1).split('&');
  queryArgs = {};
  for (var i = 0; i < query.length; ++i) {
    var val = query[i].split('=');
    if (val[0] == '') continue;
    queryArgs[decodeURIComponent(val[0])] = decodeURIComponent(val[1]);
  }

  // Apply class for icon NTP, if specified.
  USE_ICONS = queryArgs['icons'] == '1';
  if ('ntl' in queryArgs) {
    var ntl = parseInt(queryArgs['ntl'], 10);
    if (isFinite(ntl))
      NUM_TITLE_LINES = ntl;
  }

  // Duplicating NTP_DESIGN.mainClass.
  document.querySelector('#most-visited').classList.add(
      USE_ICONS ? 'icon-ntp' : 'thumb-ntp');

  // Enable RTL.
  if (queryArgs['rtl'] == '1') {
    var html = document.querySelector('html');
    html.dir = 'rtl';
  }

  window.addEventListener('message', handlePostMessage);
};


window.addEventListener('DOMContentLoaded', init);
})();