-
-
Notifications
You must be signed in to change notification settings - Fork 3.7k
/
treewalker.js
413 lines (359 loc) · 14.7 KB
/
treewalker.js
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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
/**
* @license Copyright (c) 2003-2022, CKSource Holding sp. z o.o. All rights reserved.
* For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
*/
/**
* @module engine/model/treewalker
*/
import Text from './text';
import TextProxy from './textproxy';
import Element from './element';
import {
default as Position,
getTextNodeAtPosition,
getNodeAfterPosition,
getNodeBeforePosition
} from './position';
import CKEditorError from '@ckeditor/ckeditor5-utils/src/ckeditorerror';
/**
* Position iterator class. It allows to iterate forward and backward over the document.
*/
export default class TreeWalker {
/**
* Creates a range iterator. All parameters are optional, but you have to specify either `boundaries` or `startPosition`.
*
* @constructor
* @param {Object} [options={}] Object with configuration.
* @param {'forward'|'backward'} [options.direction='forward'] Walking direction.
* @param {module:engine/model/range~Range} [options.boundaries=null] Range to define boundaries of the iterator.
* @param {module:engine/model/position~Position} [options.startPosition] Starting position.
* @param {Boolean} [options.singleCharacters=false] Flag indicating whether all consecutive characters with the same attributes
* should be returned one by one as multiple {@link module:engine/model/textproxy~TextProxy} (`true`) objects or as one
* {@link module:engine/model/textproxy~TextProxy} (`false`).
* @param {Boolean} [options.shallow=false] Flag indicating whether iterator should enter elements or not. If the
* iterator is shallow child nodes of any iterated node will not be returned along with `elementEnd` tag.
* @param {Boolean} [options.ignoreElementEnd=false] Flag indicating whether iterator should ignore `elementEnd`
* tags. If the option is true walker will not return a parent node of start position. If this option is `true`
* each {@link module:engine/model/element~Element} will be returned once, while if the option is `false` they might be returned
* twice: for `'elementStart'` and `'elementEnd'`.
*/
constructor( options = {} ) {
if ( !options.boundaries && !options.startPosition ) {
/**
* Neither boundaries nor starting position of a `TreeWalker` have been defined.
*
* @error model-tree-walker-no-start-position
*/
throw new CKEditorError(
'model-tree-walker-no-start-position',
null
);
}
const direction = options.direction || 'forward';
if ( direction != 'forward' && direction != 'backward' ) {
/**
* Only `backward` and `forward` direction allowed.
*
* @error model-tree-walker-unknown-direction
*/
throw new CKEditorError( 'model-tree-walker-unknown-direction', options, { direction } );
}
/**
* Walking direction. Defaults `'forward'`.
*
* @readonly
* @member {'backward'|'forward'} module:engine/model/treewalker~TreeWalker#direction
*/
this.direction = direction;
/**
* Iterator boundaries.
*
* When the iterator is walking `'forward'` on the end of boundary or is walking `'backward'`
* on the start of boundary, then `{ done: true }` is returned.
*
* If boundaries are not defined they are set before first and after last child of the root node.
*
* @readonly
* @member {module:engine/model/range~Range} module:engine/model/treewalker~TreeWalker#boundaries
*/
this.boundaries = options.boundaries || null;
/**
* Iterator position. This is always static position, even if the initial position was a
* {@link module:engine/model/liveposition~LivePosition live position}. If start position is not defined then position depends
* on {@link #direction}. If direction is `'forward'` position starts form the beginning, when direction
* is `'backward'` position starts from the end.
*
* @readonly
* @member {module:engine/model/position~Position} module:engine/model/treewalker~TreeWalker#position
*/
if ( options.startPosition ) {
this.position = options.startPosition.clone();
} else {
this.position = Position._createAt( this.boundaries[ this.direction == 'backward' ? 'end' : 'start' ] );
}
// Reset position stickiness in case it was set to other value, as the stickiness is kept after cloning.
this.position.stickiness = 'toNone';
/**
* Flag indicating whether all consecutive characters with the same attributes should be
* returned as one {@link module:engine/model/textproxy~TextProxy} (`true`) or one by one (`false`).
*
* @readonly
* @member {Boolean} module:engine/model/treewalker~TreeWalker#singleCharacters
*/
this.singleCharacters = !!options.singleCharacters;
/**
* Flag indicating whether iterator should enter elements or not. If the iterator is shallow child nodes of any
* iterated node will not be returned along with `elementEnd` tag.
*
* @readonly
* @member {Boolean} module:engine/model/treewalker~TreeWalker#shallow
*/
this.shallow = !!options.shallow;
/**
* Flag indicating whether iterator should ignore `elementEnd` tags. If the option is true walker will not
* return a parent node of the start position. If this option is `true` each {@link module:engine/model/element~Element} will
* be returned once, while if the option is `false` they might be returned twice:
* for `'elementStart'` and `'elementEnd'`.
*
* @readonly
* @member {Boolean} module:engine/model/treewalker~TreeWalker#ignoreElementEnd
*/
this.ignoreElementEnd = !!options.ignoreElementEnd;
/**
* Start boundary cached for optimization purposes.
*
* @private
* @member {module:engine/model/element~Element} module:engine/model/treewalker~TreeWalker#_boundaryStartParent
*/
this._boundaryStartParent = this.boundaries ? this.boundaries.start.parent : null;
/**
* End boundary cached for optimization purposes.
*
* @private
* @member {module:engine/model/element~Element} module:engine/model/treewalker~TreeWalker#_boundaryEndParent
*/
this._boundaryEndParent = this.boundaries ? this.boundaries.end.parent : null;
/**
* Parent of the most recently visited node. Cached for optimization purposes.
*
* @private
* @member {module:engine/model/element~Element|module:engine/model/documentfragment~DocumentFragment}
* module:engine/model/treewalker~TreeWalker#_visitedParent
*/
this._visitedParent = this.position.parent;
}
/**
* Iterable interface.
*
* @returns {Iterable.<module:engine/model/treewalker~TreeWalkerValue>}
*/
[ Symbol.iterator ]() {
return this;
}
/**
* Moves {@link #position} in the {@link #direction} skipping values as long as the callback function returns `true`.
*
* For example:
*
* walker.skip( value => value.type == 'text' ); // <paragraph>[]foo</paragraph> -> <paragraph>foo[]</paragraph>
* walker.skip( () => true ); // Move the position to the end: <paragraph>[]foo</paragraph> -> <paragraph>foo</paragraph>[]
* walker.skip( () => false ); // Do not move the position.
*
* @param {Function} skip Callback function. Gets {@link module:engine/model/treewalker~TreeWalkerValue} and should
* return `true` if the value should be skipped or `false` if not.
*/
skip( skip ) {
let done, value, prevPosition, prevVisitedParent;
do {
prevPosition = this.position;
prevVisitedParent = this._visitedParent;
( { done, value } = this.next() );
} while ( !done && skip( value ) );
if ( !done ) {
this.position = prevPosition;
this._visitedParent = prevVisitedParent;
}
}
/**
* Gets the next tree walker's value.
*
* @returns {module:engine/model/treewalker~TreeWalkerValue} Next tree walker's value.
*/
next() {
if ( this.direction == 'forward' ) {
return this._next();
} else {
return this._previous();
}
}
/**
* Makes a step forward in model. Moves the {@link #position} to the next position and returns the encountered value.
*
* @private
* @returns {Object}
* @returns {Boolean} return.done True if iterator is done.
* @returns {module:engine/model/treewalker~TreeWalkerValue} return.value Information about taken step.
*/
_next() {
const previousPosition = this.position;
const position = this.position.clone();
const parent = this._visitedParent;
// We are at the end of the root.
if ( parent.parent === null && position.offset === parent.maxOffset ) {
return { done: true };
}
// We reached the walker boundary.
if ( parent === this._boundaryEndParent && position.offset == this.boundaries.end.offset ) {
return { done: true };
}
// Get node just after the current position.
// Use a highly optimized version instead of checking the text node first and then getting the node after. See #6582.
const textNodeAtPosition = getTextNodeAtPosition( position, parent );
const node = textNodeAtPosition ? textNodeAtPosition : getNodeAfterPosition( position, parent, textNodeAtPosition );
if ( node instanceof Element ) {
if ( !this.shallow ) {
// Manual operations on path internals for optimization purposes. Here and in the rest of the method.
position.path.push( 0 );
this._visitedParent = node;
} else {
position.offset++;
}
this.position = position;
return formatReturnValue( 'elementStart', node, previousPosition, position, 1 );
} else if ( node instanceof Text ) {
let charactersCount;
if ( this.singleCharacters ) {
charactersCount = 1;
} else {
let offset = node.endOffset;
if ( this._boundaryEndParent == parent && this.boundaries.end.offset < offset ) {
offset = this.boundaries.end.offset;
}
charactersCount = offset - position.offset;
}
const offsetInTextNode = position.offset - node.startOffset;
const item = new TextProxy( node, offsetInTextNode, charactersCount );
position.offset += charactersCount;
this.position = position;
return formatReturnValue( 'text', item, previousPosition, position, charactersCount );
} else {
// `node` is not set, we reached the end of current `parent`.
position.path.pop();
position.offset++;
this.position = position;
this._visitedParent = parent.parent;
if ( this.ignoreElementEnd ) {
return this._next();
} else {
return formatReturnValue( 'elementEnd', parent, previousPosition, position );
}
}
}
/**
* Makes a step backward in model. Moves the {@link #position} to the previous position and returns the encountered value.
*
* @private
* @returns {Object}
* @returns {Boolean} return.done True if iterator is done.
* @returns {module:engine/model/treewalker~TreeWalkerValue} return.value Information about taken step.
*/
_previous() {
const previousPosition = this.position;
const position = this.position.clone();
const parent = this._visitedParent;
// We are at the beginning of the root.
if ( parent.parent === null && position.offset === 0 ) {
return { done: true };
}
// We reached the walker boundary.
if ( parent == this._boundaryStartParent && position.offset == this.boundaries.start.offset ) {
return { done: true };
}
// Get node just before the current position.
// Use a highly optimized version instead of checking the text node first and then getting the node before. See #6582.
const positionParent = position.parent;
const textNodeAtPosition = getTextNodeAtPosition( position, positionParent );
const node = textNodeAtPosition ? textNodeAtPosition : getNodeBeforePosition( position, positionParent, textNodeAtPosition );
if ( node instanceof Element ) {
position.offset--;
if ( !this.shallow ) {
position.path.push( node.maxOffset );
this.position = position;
this._visitedParent = node;
if ( this.ignoreElementEnd ) {
return this._previous();
} else {
return formatReturnValue( 'elementEnd', node, previousPosition, position );
}
} else {
this.position = position;
return formatReturnValue( 'elementStart', node, previousPosition, position, 1 );
}
} else if ( node instanceof Text ) {
let charactersCount;
if ( this.singleCharacters ) {
charactersCount = 1;
} else {
let offset = node.startOffset;
if ( this._boundaryStartParent == parent && this.boundaries.start.offset > offset ) {
offset = this.boundaries.start.offset;
}
charactersCount = position.offset - offset;
}
const offsetInTextNode = position.offset - node.startOffset;
const item = new TextProxy( node, offsetInTextNode - charactersCount, charactersCount );
position.offset -= charactersCount;
this.position = position;
return formatReturnValue( 'text', item, previousPosition, position, charactersCount );
} else {
// `node` is not set, we reached the beginning of current `parent`.
position.path.pop();
this.position = position;
this._visitedParent = parent.parent;
return formatReturnValue( 'elementStart', parent, previousPosition, position, 1 );
}
}
}
function formatReturnValue( type, item, previousPosition, nextPosition, length ) {
return {
done: false,
value: {
type,
item,
previousPosition,
nextPosition,
length
}
};
}
/**
* Type of the step made by {@link module:engine/model/treewalker~TreeWalker}.
* Possible values: `'elementStart'` if walker is at the beginning of a node, `'elementEnd'` if walker is at the end of node,
* or `'text'` if walker traversed over text.
*
* @typedef {'elementStart'|'elementEnd'|'text'} module:engine/model/treewalker~TreeWalkerValueType
*/
/**
* Object returned by {@link module:engine/model/treewalker~TreeWalker} when traversing tree model.
*
* @typedef {Object} module:engine/model/treewalker~TreeWalkerValue
* @property {module:engine/model/treewalker~TreeWalkerValueType} type
* @property {module:engine/model/item~Item} item Item between old and new positions of {@link module:engine/model/treewalker~TreeWalker}.
* @property {module:engine/model/position~Position} previousPosition Previous position of the iterator.
* * Forward iteration: For `'elementEnd'` it is the last position inside the element. For all other types it is the
* position before the item.
* * Backward iteration: For `'elementStart'` it is the first position inside the element. For all other types it is
* the position after item.
* @property {module:engine/model/position~Position} nextPosition Next position of the iterator.
* * Forward iteration: For `'elementStart'` it is the first position inside the element. For all other types it is
* the position after the item.
* * Backward iteration: For `'elementEnd'` it is last position inside element. For all other types it is the position
* before the item.
* @property {Number} [length] Length of the item. For `'elementStart'` it is 1. For `'text'` it is
* the length of the text. For `'elementEnd'` it is `undefined`.
*/
/**
* Tree walking directions.
*
* @typedef {'forward'|'backward'} module:engine/model/treewalker~TreeWalkerDirection
*/