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phab/webroot/rsrc/js/core/DraggableList.js
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DraggableList.js
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/**
* @provides phabricator-draggable-list
* @requires javelin-install
* javelin-dom
* javelin-stratcom
* javelin-util
* javelin-vector
* javelin-magical-init
* @javelin
*/
JX.install('DraggableList', {
construct : function(sigil, root) {
this._sigil = sigil;
this._root = root || document.body;
this._group = [this];
// NOTE: Javelin does not dispatch mousemove by default.
JX.enableDispatch(document.body, 'mousemove');
JX.DOM.listen(this._root, 'mousedown', sigil, JX.bind(this, this._ondrag));
JX.Stratcom.listen('mousemove', null, JX.bind(this, this._onmove));
JX.Stratcom.listen('scroll', null, JX.bind(this, this._onmove));
JX.Stratcom.listen('mouseup', null, JX.bind(this, this._ondrop));
},
events : [
'didLock',
'didUnlock',
'shouldBeginDrag',
'didBeginDrag',
'didCancelDrag',
'didEndDrag',
'didDrop',
'didSend',
'didReceive'],
properties : {
findItemsHandler : null
},
members : {
_root : null,
_dragging : null,
_locked : 0,
_origin : null,
_originScroll : null,
_target : null,
_targets : null,
_ghostHandler : null,
_ghostNode : null,
_group : null,
_lastMousePosition: null,
_lastAdjust: null,
getRootNode : function() {
return this._root;
},
setGhostHandler : function(handler) {
this._ghostHandler = handler;
return this;
},
getGhostHandler : function() {
return this._ghostHandler || JX.bind(this, this._defaultGhostHandler);
},
getGhostNode : function() {
if (!this._ghostNode) {
this._ghostNode = JX.$N('li', {className: 'drag-ghost'});
}
return this._ghostNode;
},
setGhostNode : function(node) {
this._ghostNode = node;
return this;
},
setGroup : function(lists) {
var result = [];
var need_self = true;
for (var ii = 0; ii < lists.length; ii++) {
if (lists[ii] == this) {
need_self = false;
}
result.push(lists[ii]);
}
if (need_self) {
result.push(this);
}
this._group = result;
return this;
},
_canDragX : function() {
return this._hasGroup();
},
_hasGroup : function() {
return (this._group.length > 1);
},
_defaultGhostHandler : function(ghost, target) {
var parent;
if (!this._hasGroup()) {
parent = this._dragging.parentNode;
} else {
parent = this.getRootNode();
}
if (target && target.nextSibling) {
parent.insertBefore(ghost, target.nextSibling);
} else if (!target && parent.firstChild) {
parent.insertBefore(ghost, parent.firstChild);
} else {
parent.appendChild(ghost);
}
},
findItems : function() {
var handler = this.getFindItemsHandler();
if (__DEV__) {
if (!handler) {
JX.$E('JX.Draggable.findItems(): No findItemsHandler set!');
}
}
return handler();
},
_ondrag : function(e) {
if (this._dragging) {
// Don't start dragging if we're already dragging something.
return;
}
if (this._locked) {
// Don't start drag operations while locked.
return;
}
if (!e.isNormalMouseEvent()) {
// Don't start dragging for shift click, right click, etc.
return;
}
if (this.invoke('shouldBeginDrag', e).getPrevented()) {
return;
}
if (e.getNode('tag:a')) {
// Never start a drag if we're somewhere inside an <a> tag. This makes
// links unclickable in Firefox.
return;
}
if (JX.Stratcom.pass()) {
// Let other handlers deal with this event before we do.
return;
}
e.kill();
this._dragging = e.getNode(this._sigil);
this._origin = JX.$V(e);
this._originScroll = JX.Vector.getAggregateScrollForNode(this._dragging);
for (var ii = 0; ii < this._group.length; ii++) {
this._group[ii]._clearTarget();
}
if (!this.invoke('didBeginDrag', this._dragging).getPrevented()) {
// Set the height of all the ghosts in the group. In the normal case,
// this just sets this list's ghost height.
for (var jj = 0; jj < this._group.length; jj++) {
var ghost = this._group[jj].getGhostNode();
ghost.style.height = JX.Vector.getDim(this._dragging).y + 'px';
}
JX.DOM.alterClass(this._dragging, 'drag-dragging', true);
}
},
_getTargets : function() {
if (this._targets === null) {
var targets = [];
var items = this.findItems();
for (var ii = 0; ii < items.length; ii++) {
var item = items[ii];
var ipos = JX.$V(item);
if (item == this._dragging) {
// If the item we're measuring is also the item we're dragging,
// we need to measure its position as though it was still in the
// list, not its current position in the document (which is
// under the cursor). To do this, adjust the measured position by
// removing the offsets we added to put the item underneath the
// cursor.
if (this._lastAdjust) {
ipos.x -= this._lastAdjust.x;
ipos.y -= this._lastAdjust.y;
}
}
targets.push({
item: items[ii],
y: ipos.y + (JX.Vector.getDim(items[ii]).y / 2)
});
}
targets.sort(function(u, v) { return v.y - u.y; });
this._targets = targets;
}
return this._targets;
},
_dirtyTargetCache: function() {
if (this._hasGroup()) {
var group = this._group;
for (var ii = 0; ii < group.length; ii++) {
group[ii]._targets = null;
}
} else {
this._targets = null;
}
return this;
},
_getTargetList : function(p) {
var target_list;
if (this._hasGroup()) {
var group = this._group;
for (var ii = 0; ii < group.length; ii++) {
var root = group[ii].getRootNode();
var rp = JX.$V(root);
var rd = JX.Vector.getDim(root);
var is_target = false;
if (p.x >= rp.x && p.y >= rp.y) {
if (p.x <= (rp.x + rd.x) && p.y <= (rp.y + rd.y)) {
is_target = true;
target_list = group[ii];
}
}
JX.DOM.alterClass(root, 'drag-target-list', is_target);
}
} else {
target_list = this;
}
return target_list;
},
_setTarget : function(cur_target) {
var ghost = this.getGhostNode();
var target = this._target;
if (cur_target !== target) {
this._clearTarget();
if (cur_target !== false) {
var ok = this.getGhostHandler()(ghost, cur_target);
// If the handler returns explicit `false`, prevent the drag.
if (ok === false) {
cur_target = false;
}
}
this._target = cur_target;
}
return this;
},
_clearTarget : function() {
var target = this._target;
var ghost = this.getGhostNode();
if (target !== false) {
JX.DOM.remove(ghost);
}
this._target = false;
// Clear the target position cache, since adding or removing ghosts
// changes element positions.
this._dirtyTargetCache();
return this;
},
_getCurrentTarget : function(p) {
var ghost = this.getGhostNode();
var targets = this._getTargets();
var dragging = this._dragging;
// Find the node we're dragging the object underneath. This is the first
// node in the list that's above the cursor. If that node is the node
// we're dragging or its predecessor, don't select a target, because the
// operation would be a no-op.
// NOTE: When we're dragging into the first position in the list, we
// use the target `null`. When we don't have a valid target, we use
// the target `false`. Spooky! Magic! Anyway, `null` and `false` mean
// completely different things.
var cur_target = null;
var trigger;
for (var ii = 0; ii < targets.length; ii++) {
trigger = targets[ii].y;
// If the cursor is above this target, we aren't dropping underneath it.
if (trigger >= p.y) {
continue;
}
// Don't choose the dragged row or its predecessor as targets.
cur_target = targets[ii].item;
if (!dragging) {
// If the item on the cursor isn't from this list, it can't be
// dropped onto itself or its predecessor in this list.
} else {
if (cur_target === dragging) {
cur_target = false;
}
if (targets[ii - 1] && (targets[ii - 1].item === dragging)) {
cur_target = false;
}
}
break;
}
// If the dragged row is the first row, don't allow it to be dragged
// into the first position, since this operation doesn't make sense.
if (dragging && cur_target === null) {
var first_item = targets[targets.length - 1].item;
if (dragging === first_item) {
cur_target = false;
}
}
return cur_target;
},
_onmove : function(e) {
// We'll get a callback here for "mousemove" (and can determine the
// location of the cursor) and also for "scroll" (and can not). If this
// is a move, save the mouse position, so if we get a scroll next we can
// reuse the known position.
if (e.getType() == 'mousemove') {
this._lastMousePosition = JX.$V(e);
}
if (!this._dragging) {
return;
}
if (!this._lastMousePosition) {
return;
}
if (e.getType() == 'scroll') {
// If this is a scroll event, the positions of drag targets may have
// changed.
this._dirtyTargetCache();
}
var p = JX.$V(this._lastMousePosition.x, this._lastMousePosition.y);
var group = this._group;
var target_list = this._getTargetList(p);
// Compute the size and position of the drop target indicator, because we
// need to update our static position computations to account for it.
var cur_target = false;
if (target_list) {
cur_target = target_list._getCurrentTarget(p);
}
// If we've selected a new target, update the UI to show where we're
// going to drop the row.
for (var ii = 0; ii < group.length; ii++) {
if (group[ii] == target_list) {
group[ii]._setTarget(cur_target);
} else {
group[ii]._clearTarget();
}
}
// If the drop target indicator is above the cursor in the document,
// adjust the cursor position for the change in node document position.
// Do this before choosing a new target to avoid a flash of nonsense.
var scroll = JX.Vector.getAggregateScrollForNode(this._dragging);
var origin = {
x: this._origin.x + (this._originScroll.x - scroll.x),
y: this._origin.y + (this._originScroll.y - scroll.y)
};
var adjust_h = 0;
var adjust_y = 0;
if (this._target !== false) {
var ghost = this.getGhostNode();
adjust_h = JX.Vector.getDim(ghost).y;
adjust_y = JX.$V(ghost).y;
if (adjust_y <= origin.y) {
p.y -= adjust_h;
}
}
if (this._canDragX()) {
p.x -= origin.x;
} else {
p.x = 0;
}
p.y -= origin.y;
this._lastAdjust = new JX.Vector(p.x, p.y);
p.setPos(this._dragging);
e.kill();
},
_ondrop : function(e) {
if (!this._dragging) {
return;
}
var p = JX.$V(e);
var dragging = this._dragging;
this._dragging = null;
var target = false;
var ghost = false;
var target_list = this._getTargetList(p);
if (target_list) {
target = target_list._target;
ghost = target_list.getGhostNode();
}
JX.$V(0, 0).setPos(dragging);
if (target !== false) {
JX.DOM.remove(dragging);
JX.DOM.replace(ghost, dragging);
this.invoke('didSend', dragging, target_list);
target_list.invoke('didReceive', dragging, this);
target_list.invoke('didDrop', dragging, target, this);
} else {
this.invoke('didCancelDrag', dragging);
}
var group = this._group;
for (var ii = 0; ii < group.length; ii++) {
JX.DOM.alterClass(group[ii].getRootNode(), 'drag-target-list', false);
group[ii]._clearTarget();
group[ii]._lastAdjust = null;
}
if (!this.invoke('didEndDrag', dragging).getPrevented()) {
JX.DOM.alterClass(dragging, 'drag-dragging', false);
}
e.kill();
},
lock : function() {
for (var ii = 0; ii < this._group.length; ii++) {
this._group[ii]._lock();
}
return this;
},
_lock : function() {
this._locked++;
if (this._locked === 1) {
this.invoke('didLock');
}
return this;
},
unlock: function() {
for (var ii = 0; ii < this._group.length; ii++) {
this._group[ii]._unlock();
}
return this;
},
_unlock : function() {
if (__DEV__) {
if (!this._locked) {
JX.$E('JX.Draggable.unlock(): Draggable is not locked!');
}
}
this._locked--;
if (!this._locked) {
this.invoke('didUnlock');
}
return this;
}
}
});
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