Ben Murdoch | 61f157c | 2016-09-16 13:49:30 +0100 | [diff] [blame] | 1 | // Copyright 2015 the V8 project authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
| 4 | |
| 5 | var Selection = function(handler) { |
| 6 | this.handler = handler; |
| 7 | this.selectionBase = null; |
| 8 | this.lastSelection = null; |
| 9 | this.selection = new Set(); |
| 10 | } |
| 11 | |
| 12 | |
| 13 | Selection.prototype.isEmpty = function() { |
| 14 | return this.selection.size == 0; |
| 15 | } |
| 16 | |
| 17 | |
| 18 | Selection.prototype.clear = function() { |
| 19 | var handler = this.handler; |
| 20 | this.selectionBase = null; |
| 21 | this.lastSelection = null; |
| 22 | handler.select(this.selection, false); |
| 23 | handler.clear(); |
| 24 | this.selection = new Set(); |
| 25 | } |
| 26 | |
| 27 | |
| 28 | count = 0; |
| 29 | |
| 30 | Selection.prototype.select = function(s, isSelected) { |
| 31 | var handler = this.handler; |
| 32 | if (!(Symbol.iterator in Object(s))) { s = [s]; } |
| 33 | if (isSelected) { |
| 34 | let first = true; |
| 35 | for (let i of s) { |
| 36 | if (first) { |
| 37 | this.selectionBase = i; |
| 38 | this.lastSelection = i; |
| 39 | first = false; |
| 40 | } |
| 41 | this.selection.add(i); |
| 42 | } |
| 43 | } else { |
| 44 | let unselectSet = new Set(); |
| 45 | for (let i of s) { |
| 46 | if (this.selection.has(i)) { |
| 47 | unselectSet.add(i); |
| 48 | this.selection.delete(i); |
| 49 | } |
| 50 | } |
| 51 | } |
| 52 | handler.select(this.selection, isSelected); |
| 53 | } |
| 54 | |
| 55 | |
| 56 | Selection.prototype.extendTo = function(pos) { |
| 57 | if (pos == this.lastSelection || this.lastSelection === null) return; |
| 58 | |
| 59 | var handler = this.handler; |
| 60 | var pos_diff = handler.selectionDifference(pos, true, this.lastSelection, false); |
| 61 | var unselect_diff = []; |
| 62 | if (pos_diff.length == 0) { |
| 63 | pos_diff = handler.selectionDifference(this.selectionBase, false, pos, true); |
| 64 | if (pos_diff.length != 0) { |
| 65 | unselect_diff = handler.selectionDifference(this.lastSelection, true, this.selectionBase, false); |
| 66 | this.selection = new Set(); |
| 67 | this.selection.add(this.selectionBase); |
| 68 | for (var d of pos_diff) { |
| 69 | this.selection.add(d); |
| 70 | } |
| 71 | } else { |
| 72 | unselect_diff = handler.selectionDifference(this.lastSelection, true, pos, false); |
| 73 | for (var d of unselect_diff) { |
| 74 | this.selection.delete(d); |
| 75 | } |
| 76 | } |
| 77 | } else { |
| 78 | unselect_diff = handler.selectionDifference(this.selectionBase, false, this.lastSelection, true); |
| 79 | if (unselect_diff != 0) { |
| 80 | pos_diff = handler.selectionDifference(pos, true, this.selectionBase, false); |
| 81 | if (pos_diff.length == 0) { |
| 82 | unselect_diff = handler.selectionDifference(pos, false, this.lastSelection, true); |
| 83 | } |
| 84 | for (var d of unselect_diff) { |
| 85 | this.selection.delete(d); |
| 86 | } |
| 87 | } |
| 88 | if (pos_diff.length != 0) { |
| 89 | for (var d of pos_diff) { |
| 90 | this.selection.add(d); |
| 91 | } |
| 92 | } |
| 93 | } |
| 94 | handler.select(unselect_diff, false); |
| 95 | handler.select(pos_diff, true); |
| 96 | this.lastSelection = pos; |
| 97 | } |
| 98 | |
| 99 | |
| 100 | Selection.prototype.detachSelection = function() { |
| 101 | var result = new Set(); |
| 102 | for (var i of this.selection) { |
| 103 | result.add(i); |
| 104 | } |
| 105 | this.clear(); |
| 106 | return result; |
| 107 | } |