summaryrefslogtreecommitdiffstats
path: root/components/newtab/drop.js
blob: 748652455c86d9f0c969d334d633d1bdfc7e5708 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
#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

// A little delay that prevents the grid from being too sensitive when dragging
// sites around.
const DELAY_REARRANGE_MS = 100;

/**
 * This singleton implements site dropping functionality.
 */
var gDrop = {
  /**
   * The last drop target.
   */
  _lastDropTarget: null,

  /**
   * Handles the 'dragenter' event.
   * @param aCell The drop target cell.
   */
  enter: function Drop_enter(aCell) {
    this._delayedRearrange(aCell);
  },

  /**
   * Handles the 'dragexit' event.
   * @param aCell The drop target cell.
   * @param aEvent The 'dragexit' event.
   */
  exit: function Drop_exit(aCell, aEvent) {
    if (aEvent.dataTransfer && !aEvent.dataTransfer.mozUserCancelled) {
      this._delayedRearrange();
    } else {
      // The drag operation has been cancelled.
      this._cancelDelayedArrange();
      this._rearrange();
    }
  },

  /**
   * Handles the 'drop' event.
   * @param aCell The drop target cell.
   * @param aEvent The 'dragexit' event.
   */
  drop: function Drop_drop(aCell, aEvent) {
    // The cell that is the drop target could contain a pinned site. We need
    // to find out where that site has gone and re-pin it there.
    if (aCell.containsPinnedSite())
      this._repinSitesAfterDrop(aCell);

    // Pin the dragged or insert the new site.
    this._pinDraggedSite(aCell, aEvent);

    this._cancelDelayedArrange();

    // Update the grid and move all sites to their new places.
    gUpdater.updateGrid();
  },

  /**
   * Re-pins all pinned sites in their (new) positions.
   * @param aCell The drop target cell.
   */
  _repinSitesAfterDrop: function Drop_repinSitesAfterDrop(aCell) {
    let sites = gDropPreview.rearrange(aCell);

    // Filter out pinned sites.
    let pinnedSites = sites.filter(function (aSite) {
      return aSite && aSite.isPinned();
    });

    // Re-pin all shifted pinned cells.
    pinnedSites.forEach(aSite => aSite.pin(sites.indexOf(aSite)));
  },

  /**
   * Pins the dragged site in its new place.
   * @param aCell The drop target cell.
   * @param aEvent The 'dragexit' event.
   */
  _pinDraggedSite: function Drop_pinDraggedSite(aCell, aEvent) {
    let index = aCell.index;
    let draggedSite = gDrag.draggedSite;

    if (draggedSite) {
      // Pin the dragged site at its new place.
      if (aCell != draggedSite.cell)
        draggedSite.pin(index);
    } else {
      let link = gDragDataHelper.getLinkFromDragEvent(aEvent);
      if (link) {
        // A new link was dragged onto the grid. Create it by pinning its URL.
        gPinnedLinks.pin(link, index);

        // Make sure the newly added link is not blocked.
        gBlockedLinks.unblock(link);
      }
    }
  },

  /**
   * Time a rearrange with a little delay.
   * @param aCell The drop target cell.
   */
  _delayedRearrange: function Drop_delayedRearrange(aCell) {
    // The last drop target didn't change so there's no need to re-arrange.
    if (this._lastDropTarget == aCell)
      return;

    let self = this;

    function callback() {
      self._rearrangeTimeout = null;
      self._rearrange(aCell);
    }

    this._cancelDelayedArrange();
    this._rearrangeTimeout = setTimeout(callback, DELAY_REARRANGE_MS);

    // Store the last drop target.
    this._lastDropTarget = aCell;
  },

  /**
   * Cancels a timed rearrange, if any.
   */
  _cancelDelayedArrange: function Drop_cancelDelayedArrange() {
    if (this._rearrangeTimeout) {
      clearTimeout(this._rearrangeTimeout);
      this._rearrangeTimeout = null;
    }
  },

  /**
   * Rearrange all sites in the grid depending on the current drop target.
   * @param aCell The drop target cell.
   */
  _rearrange: function Drop_rearrange(aCell) {
    let sites = gGrid.sites;

    // We need to rearrange the grid only if there's a current drop target.
    if (aCell)
      sites = gDropPreview.rearrange(aCell);

    gTransformation.rearrangeSites(sites, {unfreeze: !aCell});
  }
};