1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/browser/base/content/newtab/dropPreview.js Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,222 @@
1.4 +#ifdef 0
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.7 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +#endif
1.9 +
1.10 +/**
1.11 + * This singleton provides the ability to re-arrange the current grid to
1.12 + * indicate the transformation that results from dropping a cell at a certain
1.13 + * position.
1.14 + */
1.15 +let gDropPreview = {
1.16 + /**
1.17 + * Rearranges the sites currently contained in the grid when a site would be
1.18 + * dropped onto the given cell.
1.19 + * @param aCell The drop target cell.
1.20 + * @return The re-arranged array of sites.
1.21 + */
1.22 + rearrange: function DropPreview_rearrange(aCell) {
1.23 + let sites = gGrid.sites;
1.24 +
1.25 + // Insert the dragged site into the current grid.
1.26 + this._insertDraggedSite(sites, aCell);
1.27 +
1.28 + // After the new site has been inserted we need to correct the positions
1.29 + // of all pinned tabs that have been moved around.
1.30 + this._repositionPinnedSites(sites, aCell);
1.31 +
1.32 + return sites;
1.33 + },
1.34 +
1.35 + /**
1.36 + * Inserts the currently dragged site into the given array of sites.
1.37 + * @param aSites The array of sites to insert into.
1.38 + * @param aCell The drop target cell.
1.39 + */
1.40 + _insertDraggedSite: function DropPreview_insertDraggedSite(aSites, aCell) {
1.41 + let dropIndex = aCell.index;
1.42 + let draggedSite = gDrag.draggedSite;
1.43 +
1.44 + // We're currently dragging a site.
1.45 + if (draggedSite) {
1.46 + let dragCell = draggedSite.cell;
1.47 + let dragIndex = dragCell.index;
1.48 +
1.49 + // Move the dragged site into its new position.
1.50 + if (dragIndex != dropIndex) {
1.51 + aSites.splice(dragIndex, 1);
1.52 + aSites.splice(dropIndex, 0, draggedSite);
1.53 + }
1.54 + // We're handling an external drag item.
1.55 + } else {
1.56 + aSites.splice(dropIndex, 0, null);
1.57 + }
1.58 + },
1.59 +
1.60 + /**
1.61 + * Correct the position of all pinned sites that might have been moved to
1.62 + * different positions after the dragged site has been inserted.
1.63 + * @param aSites The array of sites containing the dragged site.
1.64 + * @param aCell The drop target cell.
1.65 + */
1.66 + _repositionPinnedSites:
1.67 + function DropPreview_repositionPinnedSites(aSites, aCell) {
1.68 +
1.69 + // Collect all pinned sites.
1.70 + let pinnedSites = this._filterPinnedSites(aSites, aCell);
1.71 +
1.72 + // Correct pinned site positions.
1.73 + pinnedSites.forEach(function (aSite) {
1.74 + aSites[aSites.indexOf(aSite)] = aSites[aSite.cell.index];
1.75 + aSites[aSite.cell.index] = aSite;
1.76 + }, this);
1.77 +
1.78 + // There might be a pinned cell that got pushed out of the grid, try to
1.79 + // sneak it in by removing a lower-priority cell.
1.80 + if (this._hasOverflowedPinnedSite(aSites, aCell))
1.81 + this._repositionOverflowedPinnedSite(aSites, aCell);
1.82 + },
1.83 +
1.84 + /**
1.85 + * Filter pinned sites out of the grid that are still on their old positions
1.86 + * and have not moved.
1.87 + * @param aSites The array of sites to filter.
1.88 + * @param aCell The drop target cell.
1.89 + * @return The filtered array of sites.
1.90 + */
1.91 + _filterPinnedSites: function DropPreview_filterPinnedSites(aSites, aCell) {
1.92 + let draggedSite = gDrag.draggedSite;
1.93 +
1.94 + // When dropping on a cell that contains a pinned site make sure that all
1.95 + // pinned cells surrounding the drop target are moved as well.
1.96 + let range = this._getPinnedRange(aCell);
1.97 +
1.98 + return aSites.filter(function (aSite, aIndex) {
1.99 + // The site must be valid, pinned and not the dragged site.
1.100 + if (!aSite || aSite == draggedSite || !aSite.isPinned())
1.101 + return false;
1.102 +
1.103 + let index = aSite.cell.index;
1.104 +
1.105 + // If it's not in the 'pinned range' it's a valid pinned site.
1.106 + return (index > range.end || index < range.start);
1.107 + });
1.108 + },
1.109 +
1.110 + /**
1.111 + * Determines the range of pinned sites surrounding the drop target cell.
1.112 + * @param aCell The drop target cell.
1.113 + * @return The range of pinned cells.
1.114 + */
1.115 + _getPinnedRange: function DropPreview_getPinnedRange(aCell) {
1.116 + let dropIndex = aCell.index;
1.117 + let range = {start: dropIndex, end: dropIndex};
1.118 +
1.119 + // We need a pinned range only when dropping on a pinned site.
1.120 + if (aCell.containsPinnedSite()) {
1.121 + let links = gPinnedLinks.links;
1.122 +
1.123 + // Find all previous siblings of the drop target that are pinned as well.
1.124 + while (range.start && links[range.start - 1])
1.125 + range.start--;
1.126 +
1.127 + let maxEnd = links.length - 1;
1.128 +
1.129 + // Find all next siblings of the drop target that are pinned as well.
1.130 + while (range.end < maxEnd && links[range.end + 1])
1.131 + range.end++;
1.132 + }
1.133 +
1.134 + return range;
1.135 + },
1.136 +
1.137 + /**
1.138 + * Checks if the given array of sites contains a pinned site that has
1.139 + * been pushed out of the grid.
1.140 + * @param aSites The array of sites to check.
1.141 + * @param aCell The drop target cell.
1.142 + * @return Whether there is an overflowed pinned cell.
1.143 + */
1.144 + _hasOverflowedPinnedSite:
1.145 + function DropPreview_hasOverflowedPinnedSite(aSites, aCell) {
1.146 +
1.147 + // If the drop target isn't pinned there's no way a pinned site has been
1.148 + // pushed out of the grid so we can just exit here.
1.149 + if (!aCell.containsPinnedSite())
1.150 + return false;
1.151 +
1.152 + let cells = gGrid.cells;
1.153 +
1.154 + // No cells have been pushed out of the grid, nothing to do here.
1.155 + if (aSites.length <= cells.length)
1.156 + return false;
1.157 +
1.158 + let overflowedSite = aSites[cells.length];
1.159 +
1.160 + // Nothing to do if the site that got pushed out of the grid is not pinned.
1.161 + return (overflowedSite && overflowedSite.isPinned());
1.162 + },
1.163 +
1.164 + /**
1.165 + * We have a overflowed pinned site that we need to re-position so that it's
1.166 + * visible again. We try to find a lower-priority cell (empty or containing
1.167 + * an unpinned site) that we can move it to.
1.168 + * @param aSites The array of sites.
1.169 + * @param aCell The drop target cell.
1.170 + */
1.171 + _repositionOverflowedPinnedSite:
1.172 + function DropPreview_repositionOverflowedPinnedSite(aSites, aCell) {
1.173 +
1.174 + // Try to find a lower-priority cell (empty or containing an unpinned site).
1.175 + let index = this._indexOfLowerPrioritySite(aSites, aCell);
1.176 +
1.177 + if (index > -1) {
1.178 + let cells = gGrid.cells;
1.179 + let dropIndex = aCell.index;
1.180 +
1.181 + // Move all pinned cells to their new positions to let the overflowed
1.182 + // site fit into the grid.
1.183 + for (let i = index + 1, lastPosition = index; i < aSites.length; i++) {
1.184 + if (i != dropIndex) {
1.185 + aSites[lastPosition] = aSites[i];
1.186 + lastPosition = i;
1.187 + }
1.188 + }
1.189 +
1.190 + // Finally, remove the overflowed site from its previous position.
1.191 + aSites.splice(cells.length, 1);
1.192 + }
1.193 + },
1.194 +
1.195 + /**
1.196 + * Finds the index of the last cell that is empty or contains an unpinned
1.197 + * site. These are considered to be of a lower priority.
1.198 + * @param aSites The array of sites.
1.199 + * @param aCell The drop target cell.
1.200 + * @return The cell's index.
1.201 + */
1.202 + _indexOfLowerPrioritySite:
1.203 + function DropPreview_indexOfLowerPrioritySite(aSites, aCell) {
1.204 +
1.205 + let cells = gGrid.cells;
1.206 + let dropIndex = aCell.index;
1.207 +
1.208 + // Search (beginning with the last site in the grid) for a site that is
1.209 + // empty or unpinned (an thus lower-priority) and can be pushed out of the
1.210 + // grid instead of the pinned site.
1.211 + for (let i = cells.length - 1; i >= 0; i--) {
1.212 + // The cell that is our drop target is not a good choice.
1.213 + if (i == dropIndex)
1.214 + continue;
1.215 +
1.216 + let site = aSites[i];
1.217 +
1.218 + // We can use the cell only if it's empty or the site is un-pinned.
1.219 + if (!site || !site.isPinned())
1.220 + return i;
1.221 + }
1.222 +
1.223 + return -1;
1.224 + }
1.225 +};
