The Tor Browser / file revision

 #ifdef 0

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this file,

  * You can obtain one at http://mozilla.org/MPL/2.0/. */

 #endif

 /**

  * This singleton provides functionality to update the current grid to a new

  * set of pinned and blocked sites. It adds, moves and removes sites.

  */

 let gUpdater = {

   /**

    * Updates the current grid according to its pinned and blocked sites.

    * This removes old, moves existing and creates new sites to fill gaps.

    * @param aCallback The callback to call when finished.

    */

   updateGrid: function Updater_updateGrid(aCallback) {

     let links = gLinks.getLinks().slice(0, gGrid.cells.length);

     // Find all sites that remain in the grid.

     let sites = this._findRemainingSites(links);

     let self = this;

     // Remove sites that are no longer in the grid.

     this._removeLegacySites(sites, function () {

       // Freeze all site positions so that we can move their DOM nodes around

       // without any visual impact.

       self._freezeSitePositions(sites);

       // Move the sites' DOM nodes to their new position in the DOM. This will

       // have no visual effect as all the sites have been frozen and will

       // remain in their current position.

       self._moveSiteNodes(sites);

       // Now it's time to animate the sites actually moving to their new

       // positions.

       self._rearrangeSites(sites, function () {

         // Try to fill empty cells and finish.

         self._fillEmptyCells(links, aCallback);

         // Update other pages that might be open to keep them synced.

         gAllPages.update(gPage);

       });

     });

   },

   /**

    * Takes an array of links and tries to correlate them to sites contained in

    * the current grid. If no corresponding site can be found (i.e. the link is

    * new and a site will be created) then just set it to null.

    * @param aLinks The array of links to find sites for.

    * @return Array of sites mapped to the given links (can contain null values).

    */

   _findRemainingSites: function Updater_findRemainingSites(aLinks) {

     let map = {};

     // Create a map to easily retrieve the site for a given URL.

     gGrid.sites.forEach(function (aSite) {

       if (aSite)

         map[aSite.url] = aSite;

     });

     // Map each link to its corresponding site, if any.

     return aLinks.map(function (aLink) {

       return aLink && (aLink.url in map) && map[aLink.url];

     });

   },

   /**

    * Freezes the given sites' positions.

    * @param aSites The array of sites to freeze.

    */

   _freezeSitePositions: function Updater_freezeSitePositions(aSites) {

     aSites.forEach(function (aSite) {

       if (aSite)

         gTransformation.freezeSitePosition(aSite);

     });

   },

   /**

    * Moves the given sites' DOM nodes to their new positions.

    * @param aSites The array of sites to move.

    */

   _moveSiteNodes: function Updater_moveSiteNodes(aSites) {

     let cells = gGrid.cells;

     // Truncate the given array of sites to not have more sites than cells.

     // This can happen when the user drags a bookmark (or any other new kind

     // of link) onto the grid.

     let sites = aSites.slice(0, cells.length);

     sites.forEach(function (aSite, aIndex) {

       let cell = cells[aIndex];

       let cellSite = cell.site;

       // The site's position didn't change.

       if (!aSite || cellSite != aSite) {

         let cellNode = cell.node;

         // Empty the cell if necessary.

         if (cellSite)

           cellNode.removeChild(cellSite.node);

         // Put the new site in place, if any.

         if (aSite)

           cellNode.appendChild(aSite.node);

       }

     }, this);

   },

   /**

    * Rearranges the given sites and slides them to their new positions.

    * @param aSites The array of sites to re-arrange.

    * @param aCallback The callback to call when finished.

    */

   _rearrangeSites: function Updater_rearrangeSites(aSites, aCallback) {

     let options = {callback: aCallback, unfreeze: true};

     gTransformation.rearrangeSites(aSites, options);

   },

   /**

    * Removes all sites from the grid that are not in the given links array or

    * exceed the grid.

    * @param aSites The array of sites remaining in the grid.

    * @param aCallback The callback to call when finished.

    */

   _removeLegacySites: function Updater_removeLegacySites(aSites, aCallback) {

     let batch = [];

     // Delete sites that were removed from the grid.

     gGrid.sites.forEach(function (aSite) {

       // The site must be valid and not in the current grid.

       if (!aSite || aSites.indexOf(aSite) != -1)

         return;

       let deferred = Promise.defer();

       batch.push(deferred.promise);

       // Fade out the to-be-removed site.

       gTransformation.hideSite(aSite, function () {

         let node = aSite.node;

         // Remove the site from the DOM.

         node.parentNode.removeChild(node);

         deferred.resolve();

       });

     });

     Promise.all(batch).then(aCallback);

   },

   /**

    * Tries to fill empty cells with new links if available.

    * @param aLinks The array of links.

    * @param aCallback The callback to call when finished.

    */

   _fillEmptyCells: function Updater_fillEmptyCells(aLinks, aCallback) {

     let {cells, sites} = gGrid;

     let batch = [];

     // Find empty cells and fill them.

     sites.forEach(function (aSite, aIndex) {

       if (aSite || !aLinks[aIndex])

         return;

       let deferred = Promise.defer();

       batch.push(deferred.promise);

       // Create the new site and fade it in.

       let site = gGrid.createSite(aLinks[aIndex], cells[aIndex]);

       // Set the site's initial opacity to zero.

       site.node.style.opacity = 0;

       // Flush all style changes for the dynamically inserted site to make

       // the fade-in transition work.

       window.getComputedStyle(site.node).opacity;

       gTransformation.showSite(site, function () deferred.resolve());

     });

     Promise.all(batch).then(aCallback);

   }

 };