The Tor Browser: browser/base/content/newtab/dropPreview.js@6474c204b198 (annotated)

browser/base/content/newtab/dropPreview.js@6474c204b198 (annotated)

browser/base/content/newtab/dropPreview.js

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 #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 the ability to re-arrange the current grid to
  * indicate the transformation that results from dropping a cell at a certain
  * position.
  */
 let gDropPreview = {
   /**
    * Rearranges the sites currently contained in the grid when a site would be
    * dropped onto the given cell.
    * @param aCell The drop target cell.
    * @return The re-arranged array of sites.
    */
   rearrange: function DropPreview_rearrange(aCell) {
     let sites = gGrid.sites;
     // Insert the dragged site into the current grid.
     this._insertDraggedSite(sites, aCell);
     // After the new site has been inserted we need to correct the positions
     // of all pinned tabs that have been moved around.
     this._repositionPinnedSites(sites, aCell);
     return sites;
   },
   /**
    * Inserts the currently dragged site into the given array of sites.
    * @param aSites The array of sites to insert into.
    * @param aCell The drop target cell.
    */
   _insertDraggedSite: function DropPreview_insertDraggedSite(aSites, aCell) {
     let dropIndex = aCell.index;
     let draggedSite = gDrag.draggedSite;
     // We're currently dragging a site.
     if (draggedSite) {
       let dragCell = draggedSite.cell;
       let dragIndex = dragCell.index;
       // Move the dragged site into its new position.
       if (dragIndex != dropIndex) {
         aSites.splice(dragIndex, 1);
         aSites.splice(dropIndex, 0, draggedSite);
       }
     // We're handling an external drag item.
     } else {
       aSites.splice(dropIndex, 0, null);
     }
   },
   /**
    * Correct the position of all pinned sites that might have been moved to
    * different positions after the dragged site has been inserted.
    * @param aSites The array of sites containing the dragged site.
    * @param aCell The drop target cell.
    */
   _repositionPinnedSites:
     function DropPreview_repositionPinnedSites(aSites, aCell) {
     // Collect all pinned sites.
     let pinnedSites = this._filterPinnedSites(aSites, aCell);
     // Correct pinned site positions.
     pinnedSites.forEach(function (aSite) {
       aSites[aSites.indexOf(aSite)] = aSites[aSite.cell.index];
       aSites[aSite.cell.index] = aSite;
     }, this);
     // There might be a pinned cell that got pushed out of the grid, try to
     // sneak it in by removing a lower-priority cell.
     if (this._hasOverflowedPinnedSite(aSites, aCell))
       this._repositionOverflowedPinnedSite(aSites, aCell);
   },
   /**
    * Filter pinned sites out of the grid that are still on their old positions
    * and have not moved.
    * @param aSites The array of sites to filter.
    * @param aCell The drop target cell.
    * @return The filtered array of sites.
    */
   _filterPinnedSites: function DropPreview_filterPinnedSites(aSites, aCell) {
     let draggedSite = gDrag.draggedSite;
     // When dropping on a cell that contains a pinned site make sure that all
     // pinned cells surrounding the drop target are moved as well.
     let range = this._getPinnedRange(aCell);
     return aSites.filter(function (aSite, aIndex) {
       // The site must be valid, pinned and not the dragged site.
       if (!aSite || aSite == draggedSite || !aSite.isPinned())
         return false;
       let index = aSite.cell.index;
       // If it's not in the 'pinned range' it's a valid pinned site.
       return (index > range.end || index < range.start);
     });
   },
   /**
    * Determines the range of pinned sites surrounding the drop target cell.
    * @param aCell The drop target cell.
    * @return The range of pinned cells.
    */
   _getPinnedRange: function DropPreview_getPinnedRange(aCell) {
     let dropIndex = aCell.index;
     let range = {start: dropIndex, end: dropIndex};
     // We need a pinned range only when dropping on a pinned site.
     if (aCell.containsPinnedSite()) {
       let links = gPinnedLinks.links;
       // Find all previous siblings of the drop target that are pinned as well.
       while (range.start && links[range.start - 1])
         range.start--;
       let maxEnd = links.length - 1;
       // Find all next siblings of the drop target that are pinned as well.
       while (range.end < maxEnd && links[range.end + 1])
         range.end++;
     }
     return range;
   },
   /**
    * Checks if the given array of sites contains a pinned site that has
    * been pushed out of the grid.
    * @param aSites The array of sites to check.
    * @param aCell The drop target cell.
    * @return Whether there is an overflowed pinned cell.
    */
   _hasOverflowedPinnedSite:
     function DropPreview_hasOverflowedPinnedSite(aSites, aCell) {
     // If the drop target isn't pinned there's no way a pinned site has been
     // pushed out of the grid so we can just exit here.
     if (!aCell.containsPinnedSite())
       return false;
     let cells = gGrid.cells;
     // No cells have been pushed out of the grid, nothing to do here.
     if (aSites.length <= cells.length)
       return false;
     let overflowedSite = aSites[cells.length];
     // Nothing to do if the site that got pushed out of the grid is not pinned.
     return (overflowedSite && overflowedSite.isPinned());
   },
   /**
    * We have a overflowed pinned site that we need to re-position so that it's
    * visible again. We try to find a lower-priority cell (empty or containing
    * an unpinned site) that we can move it to.
    * @param aSites The array of sites.
    * @param aCell The drop target cell.
    */
   _repositionOverflowedPinnedSite:
     function DropPreview_repositionOverflowedPinnedSite(aSites, aCell) {
     // Try to find a lower-priority cell (empty or containing an unpinned site).
     let index = this._indexOfLowerPrioritySite(aSites, aCell);
     if (index > -1) {
       let cells = gGrid.cells;
       let dropIndex = aCell.index;
       // Move all pinned cells to their new positions to let the overflowed
       // site fit into the grid.
       for (let i = index + 1, lastPosition = index; i < aSites.length; i++) {
         if (i != dropIndex) {
           aSites[lastPosition] = aSites[i];
           lastPosition = i;
         }
       }
       // Finally, remove the overflowed site from its previous position.
       aSites.splice(cells.length, 1);
     }
   },
   /**
    * Finds the index of the last cell that is empty or contains an unpinned
    * site. These are considered to be of a lower priority.
    * @param aSites The array of sites.
    * @param aCell The drop target cell.
    * @return The cell's index.
    */
   _indexOfLowerPrioritySite:
     function DropPreview_indexOfLowerPrioritySite(aSites, aCell) {
     let cells = gGrid.cells;
     let dropIndex = aCell.index;
     // Search (beginning with the last site in the grid) for a site that is
     // empty or unpinned (an thus lower-priority) and can be pushed out of the
     // grid instead of the pinned site.
     for (let i = cells.length - 1; i >= 0; i--) {
       // The cell that is our drop target is not a good choice.
       if (i == dropIndex)
         continue;
       let site = aSites[i];
       // We can use the cell only if it's empty or the site is un-pinned.
       if (!site || !site.isPinned())
         return i;
     }
     return -1;
   }
 };