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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
'use strict';
//Const
var NOAH_ARK_CAPACITY = 3;
//List of formatting elements
var FormattingElementList = module.exports = function (treeAdapter) {
this.length = 0;
this.entries = [];
this.treeAdapter = treeAdapter;
this.bookmark = null;
};
//Entry types
FormattingElementList.MARKER_ENTRY = 'MARKER_ENTRY';
FormattingElementList.ELEMENT_ENTRY = 'ELEMENT_ENTRY';
//Noah Ark's condition
//OPTIMIZATION: at first we try to find possible candidates for exclusion using
//lightweight heuristics without thorough attributes check.
FormattingElementList.prototype._getNoahArkConditionCandidates = function (newElement) {
var candidates = [];
if (this.length >= NOAH_ARK_CAPACITY) {
var neAttrsLength = this.treeAdapter.getAttrList(newElement).length,
neTagName = this.treeAdapter.getTagName(newElement),
neNamespaceURI = this.treeAdapter.getNamespaceURI(newElement);
for (var i = this.length - 1; i >= 0; i--) {
var entry = this.entries[i];
if (entry.type === FormattingElementList.MARKER_ENTRY)
break;
var element = entry.element,
elementAttrs = this.treeAdapter.getAttrList(element),
isCandidate = this.treeAdapter.getTagName(element) === neTagName &&
this.treeAdapter.getNamespaceURI(element) === neNamespaceURI &&
elementAttrs.length === neAttrsLength;
if (isCandidate)
candidates.push({idx: i, attrs: elementAttrs});
}
}
return candidates.length < NOAH_ARK_CAPACITY ? [] : candidates;
};
FormattingElementList.prototype._ensureNoahArkCondition = function (newElement) {
var candidates = this._getNoahArkConditionCandidates(newElement),
cLength = candidates.length;
if (cLength) {
var neAttrs = this.treeAdapter.getAttrList(newElement),
neAttrsLength = neAttrs.length,
neAttrsMap = Object.create(null);
//NOTE: build attrs map for the new element so we can perform fast lookups
for (var i = 0; i < neAttrsLength; i++) {
var neAttr = neAttrs[i];
neAttrsMap[neAttr.name] = neAttr.value;
}
for (i = 0; i < neAttrsLength; i++) {
for (var j = 0; j < cLength; j++) {
var cAttr = candidates[j].attrs[i];
if (neAttrsMap[cAttr.name] !== cAttr.value) {
candidates.splice(j, 1);
cLength--;
}
if (candidates.length < NOAH_ARK_CAPACITY)
return;
}
}
//NOTE: remove bottommost candidates until Noah's Ark condition will not be met
for (i = cLength - 1; i >= NOAH_ARK_CAPACITY - 1; i--) {
this.entries.splice(candidates[i].idx, 1);
this.length--;
}
}
};
//Mutations
FormattingElementList.prototype.insertMarker = function () {
this.entries.push({type: FormattingElementList.MARKER_ENTRY});
this.length++;
};
FormattingElementList.prototype.pushElement = function (element, token) {
this._ensureNoahArkCondition(element);
this.entries.push({
type: FormattingElementList.ELEMENT_ENTRY,
element: element,
token: token
});
this.length++;
};
FormattingElementList.prototype.insertElementAfterBookmark = function (element, token) {
var bookmarkIdx = this.length - 1;
for (; bookmarkIdx >= 0; bookmarkIdx--) {
if (this.entries[bookmarkIdx] === this.bookmark)
break;
}
this.entries.splice(bookmarkIdx + 1, 0, {
type: FormattingElementList.ELEMENT_ENTRY,
element: element,
token: token
});
this.length++;
};
FormattingElementList.prototype.removeEntry = function (entry) {
for (var i = this.length - 1; i >= 0; i--) {
if (this.entries[i] === entry) {
this.entries.splice(i, 1);
this.length--;
break;
}
}
};
FormattingElementList.prototype.clearToLastMarker = function () {
while (this.length) {
var entry = this.entries.pop();
this.length--;
if (entry.type === FormattingElementList.MARKER_ENTRY)
break;
}
};
//Search
FormattingElementList.prototype.getElementEntryInScopeWithTagName = function (tagName) {
for (var i = this.length - 1; i >= 0; i--) {
var entry = this.entries[i];
if (entry.type === FormattingElementList.MARKER_ENTRY)
return null;
if (this.treeAdapter.getTagName(entry.element) === tagName)
return entry;
}
return null;
};
FormattingElementList.prototype.getElementEntry = function (element) {
for (var i = this.length - 1; i >= 0; i--) {
var entry = this.entries[i];
if (entry.type === FormattingElementList.ELEMENT_ENTRY && entry.element === element)
return entry;
}
return null;
};
|
