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| 1 // Copyright 2014 Google Inc. | |
| 2 // | |
| 3 // Licensed under the Apache License, Version 2.0 (the "License"); | |
| 4 // you may not use this file except in compliance with the License. | |
| 5 // You may obtain a copy of the License at | |
| 6 // | |
| 7 // http://www.apache.org/licenses/LICENSE-2.0 | |
| 8 // | |
| 9 // Unless required by applicable law or agreed to in writing, software | |
| 10 // distributed under the License is distributed on an "AS IS" BASIS, | |
| 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| 12 // See the License for the specific language governing permissions and | |
| 13 // limitations under the License. | |
| 14 | |
| 15 /** | |
| 16 * @fileoverview Low-level DOM traversal utility functions to find the | |
| 17 * next (or previous) character, word, sentence, line, or paragraph, | |
| 18 * in a completely stateless manner without actually manipulating the | |
| 19 * selection. | |
| 20 */ | |
| 21 | |
| 22 /** | |
| 23 * A class to represent a cursor location in the document, | |
| 24 * like the start position or end position of a selection range. | |
| 25 * | |
| 26 * Later this may be extended to support "virtual text" for an object, | |
| 27 * like the ALT text for an image. | |
| 28 * | |
| 29 * Note: we cache the text of a particular node at the time we | |
| 30 * traverse into it. Later we should add support for dynamically | |
| 31 * reloading it. | |
| 32 * @param {Node} node The DOM node. | |
| 33 * @param {number} index The index of the character within the node. | |
| 34 * @param {string} text The cached text contents of the node. | |
| 35 * @constructor | |
| 36 */ | |
| 37 Cursor = function(node, index, text) { | |
| 38 this.node = node; | |
| 39 this.index = index; | |
| 40 this.text = text; | |
| 41 }; | |
| 42 | |
| 43 /** | |
| 44 * @return {Cursor} A new cursor pointing to the same location. | |
| 45 */ | |
| 46 Cursor.prototype.clone = function() { | |
| 47 return new Cursor(this.node, this.index, this.text); | |
| 48 }; | |
| 49 | |
| 50 /** | |
| 51 * Modify this cursor to point to the location that another cursor points to. | |
| 52 * @param {Cursor} otherCursor The cursor to copy from. | |
| 53 */ | |
| 54 Cursor.prototype.copyFrom = function(otherCursor) { | |
| 55 this.node = otherCursor.node; | |
| 56 this.index = otherCursor.index; | |
| 57 this.text = otherCursor.text; | |
| 58 }; | |
| 59 | |
| 60 /** | |
| 61 * Utility functions for stateless DOM traversal. | |
| 62 * @constructor | |
| 63 */ | |
| 64 TraverseUtil = function() {}; | |
| 65 | |
| 66 /** | |
| 67 * Gets the text representation of a node. This allows us to substitute | |
| 68 * alt text, names, or titles for html elements that provide them. | |
| 69 * @param {Node} node A DOM node. | |
| 70 * @return {string} A text string representation of the node. | |
| 71 */ | |
| 72 TraverseUtil.getNodeText = function(node) { | |
| 73 if (node.constructor == Text) { | |
| 74 return node.data; | |
| 75 } else { | |
| 76 return ''; | |
| 77 } | |
| 78 }; | |
| 79 | |
| 80 /** | |
| 81 * Return true if a node should be treated as a leaf node, because | |
| 82 * its children are properties of the object that shouldn't be traversed. | |
| 83 * | |
| 84 * TODO(dmazzoni): replace this with a predicate that detects nodes with | |
| 85 * ARIA roles and other objects that have their own description. | |
| 86 * For now we just detect a couple of common cases. | |
| 87 * | |
| 88 * @param {Node} node A DOM node. | |
| 89 * @return {boolean} True if the node should be treated as a leaf node. | |
| 90 */ | |
| 91 TraverseUtil.treatAsLeafNode = function(node) { | |
| 92 return node.childNodes.length == 0 || | |
| 93 node.nodeName == 'SELECT' || | |
| 94 node.nodeName == 'OBJECT'; | |
| 95 }; | |
| 96 | |
| 97 /** | |
| 98 * Return true only if a single character is whitespace. | |
| 99 * From https://developer.mozilla.org/en/Whitespace_in_the_DOM, | |
| 100 * whitespace is defined as one of the characters | |
| 101 * "\t" TAB \u0009 | |
| 102 * "\n" LF \u000A | |
| 103 * "\r" CR \u000D | |
| 104 * " " SPC \u0020. | |
| 105 * | |
| 106 * @param {string} c A string containing a single character. | |
| 107 * @return {boolean} True if the character is whitespace, otherwise false. | |
| 108 */ | |
| 109 TraverseUtil.isWhitespace = function(c) { | |
| 110 return (c == ' ' || c == '\n' || c == '\r' || c == '\t'); | |
| 111 }; | |
| 112 | |
| 113 /** | |
| 114 * Set the selection to the range between the given start and end cursors. | |
| 115 * @param {Cursor} start The desired start of the selection. | |
| 116 * @param {Cursor} end The desired end of the selection. | |
| 117 * @return {Selection} the selection object. | |
| 118 */ | |
| 119 TraverseUtil.setSelection = function(start, end) { | |
| 120 var sel = window.getSelection(); | |
| 121 sel.removeAllRanges(); | |
| 122 var range = document.createRange(); | |
| 123 range.setStart(start.node, start.index); | |
| 124 range.setEnd(end.node, end.index); | |
| 125 sel.addRange(range); | |
| 126 | |
| 127 return sel; | |
| 128 }; | |
| 129 | |
| 130 /** | |
| 131 * Use the computed CSS style to figure out if this DOM node is currently | |
| 132 * visible. | |
| 133 * @param {Node} node A HTML DOM node. | |
| 134 * @return {boolean} Whether or not the html node is visible. | |
| 135 */ | |
| 136 TraverseUtil.isVisible = function(node) { | |
| 137 if (!node.style) | |
| 138 return true; | |
| 139 var style = window.getComputedStyle(/** @type {Element} */(node), null); | |
| 140 return (!!style && style.display != 'none' && style.visibility != 'hidden'); | |
| 141 }; | |
| 142 | |
| 143 /** | |
| 144 * Use the class name to figure out if this DOM node should be traversed. | |
| 145 * @param {Node} node A HTML DOM node. | |
| 146 * @return {boolean} Whether or not the html node should be traversed. | |
| 147 */ | |
| 148 TraverseUtil.isSkipped = function(node) { | |
| 149 if (node.constructor == Text) | |
| 150 node = node.parentElement; | |
| 151 if (node.className == 'CaretBrowsing_Caret' || | |
| 152 node.className == 'CaretBrowsing_AnimateCaret') { | |
| 153 return true; | |
| 154 } | |
| 155 return false; | |
| 156 }; | |
| 157 | |
| 158 /** | |
| 159 * Moves the cursor forwards until it has crossed exactly one character. | |
| 160 * @param {Cursor} cursor The cursor location where the search should start. | |
| 161 * On exit, the cursor will be immediately to the right of the | |
| 162 * character returned. | |
| 163 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 164 * initial and final cursor position will be pushed onto this array. | |
| 165 * @return {?string} The character found, or null if the bottom of the | |
| 166 * document has been reached. | |
| 167 */ | |
| 168 TraverseUtil.forwardsChar = function(cursor, nodesCrossed) { | |
| 169 while (true) { | |
| 170 // Move down until we get to a leaf node. | |
| 171 var childNode = null; | |
| 172 if (!TraverseUtil.treatAsLeafNode(cursor.node)) { | |
| 173 for (var i = cursor.index; i < cursor.node.childNodes.length; i++) { | |
| 174 var node = cursor.node.childNodes[i]; | |
| 175 if (TraverseUtil.isSkipped(node)) { | |
| 176 nodesCrossed.push(node); | |
| 177 continue; | |
| 178 } | |
| 179 if (TraverseUtil.isVisible(node)) { | |
| 180 childNode = node; | |
| 181 break; | |
| 182 } | |
| 183 } | |
| 184 } | |
| 185 if (childNode) { | |
| 186 cursor.node = childNode; | |
| 187 cursor.index = 0; | |
| 188 cursor.text = TraverseUtil.getNodeText(cursor.node); | |
| 189 if (cursor.node.constructor != Text) { | |
| 190 nodesCrossed.push(cursor.node); | |
| 191 } | |
| 192 continue; | |
| 193 } | |
| 194 | |
| 195 // Return the next character from this leaf node. | |
| 196 if (cursor.index < cursor.text.length) | |
| 197 return cursor.text[cursor.index++]; | |
| 198 | |
| 199 // Move to the next sibling, going up the tree as necessary. | |
| 200 while (cursor.node != null) { | |
| 201 // Try to move to the next sibling. | |
| 202 var siblingNode = null; | |
| 203 for (var node = cursor.node.nextSibling; | |
| 204 node != null; | |
| 205 node = node.nextSibling) { | |
| 206 if (TraverseUtil.isSkipped(node)) { | |
| 207 nodesCrossed.push(node); | |
| 208 continue; | |
| 209 } | |
| 210 if (TraverseUtil.isVisible(node)) { | |
| 211 siblingNode = node; | |
| 212 break; | |
| 213 } | |
| 214 } | |
| 215 if (siblingNode) { | |
| 216 cursor.node = siblingNode; | |
| 217 cursor.text = TraverseUtil.getNodeText(siblingNode); | |
| 218 cursor.index = 0; | |
| 219 | |
| 220 if (cursor.node.constructor != Text) { | |
| 221 nodesCrossed.push(cursor.node); | |
| 222 } | |
| 223 | |
| 224 break; | |
| 225 } | |
| 226 | |
| 227 // Otherwise, move to the parent. | |
| 228 if (cursor.node.parentNode && | |
| 229 cursor.node.parentNode.constructor != HTMLBodyElement) { | |
| 230 cursor.node = cursor.node.parentNode; | |
| 231 cursor.text = null; | |
| 232 cursor.index = 0; | |
| 233 } else { | |
| 234 return null; | |
| 235 } | |
| 236 } | |
| 237 } | |
| 238 }; | |
| 239 | |
| 240 /** | |
| 241 * Moves the cursor backwards until it has crossed exactly one character. | |
| 242 * @param {Cursor} cursor The cursor location where the search should start. | |
| 243 * On exit, the cursor will be immediately to the left of the | |
| 244 * character returned. | |
| 245 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 246 * initial and final cursor position will be pushed onto this array. | |
| 247 * @return {?string} The previous character, or null if the top of the | |
| 248 * document has been reached. | |
| 249 */ | |
| 250 TraverseUtil.backwardsChar = function(cursor, nodesCrossed) { | |
| 251 while (true) { | |
| 252 // Move down until we get to a leaf node. | |
| 253 var childNode = null; | |
| 254 if (!TraverseUtil.treatAsLeafNode(cursor.node)) { | |
| 255 for (var i = cursor.index - 1; i >= 0; i--) { | |
| 256 var node = cursor.node.childNodes[i]; | |
| 257 if (TraverseUtil.isSkipped(node)) { | |
| 258 nodesCrossed.push(node); | |
| 259 continue; | |
| 260 } | |
| 261 if (TraverseUtil.isVisible(node)) { | |
| 262 childNode = node; | |
| 263 break; | |
| 264 } | |
| 265 } | |
| 266 } | |
| 267 if (childNode) { | |
| 268 cursor.node = childNode; | |
| 269 cursor.text = TraverseUtil.getNodeText(cursor.node); | |
| 270 if (cursor.text.length) | |
| 271 cursor.index = cursor.text.length; | |
| 272 else | |
| 273 cursor.index = cursor.node.childNodes.length; | |
| 274 if (cursor.node.constructor != Text) | |
| 275 nodesCrossed.push(cursor.node); | |
| 276 continue; | |
| 277 } | |
| 278 | |
| 279 // Return the previous character from this leaf node. | |
| 280 if (cursor.text.length > 0 && cursor.index > 0) { | |
| 281 return cursor.text[--cursor.index]; | |
| 282 } | |
| 283 | |
| 284 // Move to the previous sibling, going up the tree as necessary. | |
| 285 while (true) { | |
| 286 // Try to move to the previous sibling. | |
| 287 var siblingNode = null; | |
| 288 for (var node = cursor.node.previousSibling; | |
| 289 node != null; | |
| 290 node = node.previousSibling) { | |
| 291 if (TraverseUtil.isSkipped(node)) { | |
| 292 nodesCrossed.push(node); | |
| 293 continue; | |
| 294 } | |
| 295 if (TraverseUtil.isVisible(node)) { | |
| 296 siblingNode = node; | |
| 297 break; | |
| 298 } | |
| 299 } | |
| 300 if (siblingNode) { | |
| 301 cursor.node = siblingNode; | |
| 302 cursor.text = TraverseUtil.getNodeText(siblingNode); | |
| 303 if (cursor.text.length) | |
| 304 cursor.index = cursor.text.length; | |
| 305 else | |
| 306 cursor.index = cursor.node.childNodes.length; | |
| 307 if (cursor.node.constructor != Text) | |
| 308 nodesCrossed.push(cursor.node); | |
| 309 break; | |
| 310 } | |
| 311 | |
| 312 // Otherwise, move to the parent. | |
| 313 if (cursor.node.parentNode && | |
| 314 cursor.node.parentNode.constructor != HTMLBodyElement) { | |
| 315 cursor.node = cursor.node.parentNode; | |
| 316 cursor.text = null; | |
| 317 cursor.index = 0; | |
| 318 } else { | |
| 319 return null; | |
| 320 } | |
| 321 } | |
| 322 } | |
| 323 }; | |
| 324 | |
| 325 /** | |
| 326 * Finds the next character, starting from endCursor. Upon exit, startCursor | |
| 327 * and endCursor will surround the next character. If skipWhitespace is | |
| 328 * true, will skip until a real character is found. Otherwise, it will | |
| 329 * attempt to select all of the whitespace between the initial position | |
| 330 * of endCursor and the next non-whitespace character. | |
| 331 * @param {Cursor} startCursor On exit, points to the position before | |
| 332 * the char. | |
| 333 * @param {Cursor} endCursor The position to start searching for the next | |
| 334 * char. On exit, will point to the position past the char. | |
| 335 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 336 * initial and final cursor position will be pushed onto this array. | |
| 337 * @param {boolean} skipWhitespace If true, will keep scanning until a | |
| 338 * non-whitespace character is found. | |
| 339 * @return {?string} The next char, or null if the bottom of the | |
| 340 * document has been reached. | |
| 341 */ | |
| 342 TraverseUtil.getNextChar = function( | |
| 343 startCursor, endCursor, nodesCrossed, skipWhitespace) { | |
| 344 | |
| 345 // Save the starting position and get the first character. | |
| 346 startCursor.copyFrom(endCursor); | |
| 347 var c = TraverseUtil.forwardsChar(endCursor, nodesCrossed); | |
| 348 if (c == null) | |
| 349 return null; | |
| 350 | |
| 351 // Keep track of whether the first character was whitespace. | |
| 352 var initialWhitespace = TraverseUtil.isWhitespace(c); | |
| 353 | |
| 354 // Keep scanning until we find a non-whitespace or non-skipped character. | |
| 355 while ((TraverseUtil.isWhitespace(c)) || | |
| 356 (TraverseUtil.isSkipped(endCursor.node))) { | |
| 357 c = TraverseUtil.forwardsChar(endCursor, nodesCrossed); | |
| 358 if (c == null) | |
| 359 return null; | |
| 360 } | |
| 361 if (skipWhitespace || !initialWhitespace) { | |
| 362 // If skipWhitepace is true, or if the first character we encountered | |
| 363 // was not whitespace, return that non-whitespace character. | |
| 364 startCursor.copyFrom(endCursor); | |
| 365 startCursor.index--; | |
| 366 return c; | |
| 367 } | |
| 368 else { | |
| 369 for (var i = 0; i < nodesCrossed.length; i++) { | |
| 370 if (TraverseUtil.isSkipped(nodesCrossed[i])) { | |
| 371 // We need to make sure that startCursor and endCursor aren't | |
| 372 // surrounding a skippable node. | |
| 373 endCursor.index--; | |
| 374 startCursor.copyFrom(endCursor); | |
| 375 startCursor.index--; | |
| 376 return ' '; | |
| 377 } | |
| 378 } | |
| 379 // Otherwise, return all of the whitespace before that last character. | |
| 380 endCursor.index--; | |
| 381 return ' '; | |
| 382 } | |
| 383 }; | |
| 384 | |
| 385 /** | |
| 386 * Finds the previous character, starting from startCursor. Upon exit, | |
| 387 * startCursor and endCursor will surround the previous character. | |
| 388 * If skipWhitespace is true, will skip until a real character is found. | |
| 389 * Otherwise, it will attempt to select all of the whitespace between | |
| 390 * the initial position of endCursor and the next non-whitespace character. | |
| 391 * @param {Cursor} startCursor The position to start searching for the | |
| 392 * char. On exit, will point to the position before the char. | |
| 393 * @param {Cursor} endCursor The position to start searching for the next | |
| 394 * char. On exit, will point to the position past the char. | |
| 395 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 396 * initial and final cursor position will be pushed onto this array. | |
| 397 * @param {boolean} skipWhitespace If true, will keep scanning until a | |
| 398 * non-whitespace character is found. | |
| 399 * @return {?string} The previous char, or null if the top of the | |
| 400 * document has been reached. | |
| 401 */ | |
| 402 TraverseUtil.getPreviousChar = function( | |
| 403 startCursor, endCursor, nodesCrossed, skipWhitespace) { | |
| 404 | |
| 405 // Save the starting position and get the first character. | |
| 406 endCursor.copyFrom(startCursor); | |
| 407 var c = TraverseUtil.backwardsChar(startCursor, nodesCrossed); | |
| 408 if (c == null) | |
| 409 return null; | |
| 410 | |
| 411 // Keep track of whether the first character was whitespace. | |
| 412 var initialWhitespace = TraverseUtil.isWhitespace(c); | |
| 413 | |
| 414 // Keep scanning until we find a non-whitespace or non-skipped character. | |
| 415 while ((TraverseUtil.isWhitespace(c)) || | |
| 416 (TraverseUtil.isSkipped(startCursor.node))) { | |
| 417 c = TraverseUtil.backwardsChar(startCursor, nodesCrossed); | |
| 418 if (c == null) | |
| 419 return null; | |
| 420 } | |
| 421 if (skipWhitespace || !initialWhitespace) { | |
| 422 // If skipWhitepace is true, or if the first character we encountered | |
| 423 // was not whitespace, return that non-whitespace character. | |
| 424 endCursor.copyFrom(startCursor); | |
| 425 endCursor.index++; | |
| 426 return c; | |
| 427 } else { | |
| 428 for (var i = 0; i < nodesCrossed.length; i++) { | |
| 429 if (TraverseUtil.isSkipped(nodesCrossed[i])) { | |
| 430 startCursor.index++; | |
| 431 endCursor.copyFrom(startCursor); | |
| 432 endCursor.index++; | |
| 433 return ' '; | |
| 434 } | |
| 435 } | |
| 436 // Otherwise, return all of the whitespace before that last character. | |
| 437 startCursor.index++; | |
| 438 return ' '; | |
| 439 } | |
| 440 }; | |
| 441 | |
| 442 /** | |
| 443 * Finds the next word, starting from endCursor. Upon exit, startCursor | |
| 444 * and endCursor will surround the next word. A word is defined to be | |
| 445 * a string of 1 or more non-whitespace characters in the same DOM node. | |
| 446 * @param {Cursor} startCursor On exit, will point to the beginning of the | |
| 447 * word returned. | |
| 448 * @param {Cursor} endCursor The position to start searching for the next | |
| 449 * word. On exit, will point to the end of the word returned. | |
| 450 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 451 * initial and final cursor position will be pushed onto this array. | |
| 452 * @return {?string} The next word, or null if the bottom of the | |
| 453 * document has been reached. | |
| 454 */ | |
| 455 TraverseUtil.getNextWord = function(startCursor, endCursor, | |
| 456 nodesCrossed) { | |
| 457 | |
| 458 // Find the first non-whitespace or non-skipped character. | |
| 459 var cursor = endCursor.clone(); | |
| 460 var c = TraverseUtil.forwardsChar(cursor, nodesCrossed); | |
| 461 if (c == null) | |
| 462 return null; | |
| 463 while ((TraverseUtil.isWhitespace(c)) || | |
| 464 (TraverseUtil.isSkipped(cursor.node))) { | |
| 465 c = TraverseUtil.forwardsChar(cursor, nodesCrossed); | |
| 466 if (c == null) | |
| 467 return null; | |
| 468 } | |
| 469 | |
| 470 // Set startCursor to the position immediately before the first | |
| 471 // character in our word. It's safe to decrement |index| because | |
| 472 // forwardsChar guarantees that the cursor will be immediately to the | |
| 473 // right of the returned character on exit. | |
| 474 startCursor.copyFrom(cursor); | |
| 475 startCursor.index--; | |
| 476 | |
| 477 // Keep building up our word until we reach a whitespace character or | |
| 478 // would cross a tag. Don't actually return any tags crossed, because this | |
| 479 // word goes up until the tag boundary but not past it. | |
| 480 endCursor.copyFrom(cursor); | |
| 481 var word = c; | |
| 482 var newNodesCrossed = []; | |
| 483 c = TraverseUtil.forwardsChar(cursor, newNodesCrossed); | |
| 484 if (c == null) { | |
| 485 return word; | |
| 486 } | |
| 487 while (!TraverseUtil.isWhitespace(c) && | |
| 488 newNodesCrossed.length == 0) { | |
| 489 word += c; | |
| 490 endCursor.copyFrom(cursor); | |
| 491 c = TraverseUtil.forwardsChar(cursor, newNodesCrossed); | |
| 492 if (c == null) { | |
| 493 return word; | |
| 494 } | |
| 495 } | |
| 496 return word; | |
| 497 }; | |
| 498 | |
| 499 /** | |
| 500 * Finds the previous word, starting from startCursor. Upon exit, startCursor | |
| 501 * and endCursor will surround the previous word. A word is defined to be | |
| 502 * a string of 1 or more non-whitespace characters in the same DOM node. | |
| 503 * @param {Cursor} startCursor The position to start searching for the | |
| 504 * previous word. On exit, will point to the beginning of the | |
| 505 * word returned. | |
| 506 * @param {Cursor} endCursor On exit, will point to the end of the | |
| 507 * word returned. | |
| 508 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 509 * initial and final cursor position will be pushed onto this array. | |
| 510 * @return {?string} The previous word, or null if the bottom of the | |
| 511 * document has been reached. | |
| 512 */ | |
| 513 TraverseUtil.getPreviousWord = function(startCursor, endCursor, | |
| 514 nodesCrossed) { | |
| 515 // Find the first non-whitespace or non-skipped character. | |
| 516 var cursor = startCursor.clone(); | |
| 517 var c = TraverseUtil.backwardsChar(cursor, nodesCrossed); | |
| 518 if (c == null) | |
| 519 return null; | |
| 520 while ((TraverseUtil.isWhitespace(c) || | |
| 521 (TraverseUtil.isSkipped(cursor.node)))) { | |
| 522 c = TraverseUtil.backwardsChar(cursor, nodesCrossed); | |
| 523 if (c == null) | |
| 524 return null; | |
| 525 } | |
| 526 | |
| 527 // Set endCursor to the position immediately after the first | |
| 528 // character we've found (the last character of the word, since we're | |
| 529 // searching backwards). | |
| 530 endCursor.copyFrom(cursor); | |
| 531 endCursor.index++; | |
| 532 | |
| 533 // Keep building up our word until we reach a whitespace character or | |
| 534 // would cross a tag. Don't actually return any tags crossed, because this | |
| 535 // word goes up until the tag boundary but not past it. | |
| 536 startCursor.copyFrom(cursor); | |
| 537 var word = c; | |
| 538 var newNodesCrossed = []; | |
| 539 c = TraverseUtil.backwardsChar(cursor, newNodesCrossed); | |
| 540 if (c == null) | |
| 541 return word; | |
| 542 while (!TraverseUtil.isWhitespace(c) && | |
| 543 newNodesCrossed.length == 0) { | |
| 544 word = c + word; | |
| 545 startCursor.copyFrom(cursor); | |
| 546 c = TraverseUtil.backwardsChar(cursor, newNodesCrossed); | |
| 547 if (c == null) | |
| 548 return word; | |
| 549 } | |
| 550 | |
| 551 return word; | |
| 552 }; | |
| 553 | |
| 554 /** | |
| 555 * Finds the next sentence, starting from endCursor. Upon exit, | |
| 556 * startCursor and endCursor will surround the next sentence. | |
| 557 * | |
| 558 * @param {Cursor} startCursor On exit, marks the beginning of the sentence. | |
| 559 * @param {Cursor} endCursor The position to start searching for the next | |
| 560 * sentence. On exit, will point to the end of the returned string. | |
| 561 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 562 * initial and final cursor position will be pushed onto this array. | |
| 563 * @param {Object} breakTags Associative array of tags that should break | |
| 564 * the sentence. | |
| 565 * @return {?string} The next sentence, or null if the bottom of the | |
| 566 * document has been reached. | |
| 567 */ | |
| 568 TraverseUtil.getNextSentence = function( | |
| 569 startCursor, endCursor, nodesCrossed, breakTags) { | |
| 570 return TraverseUtil.getNextString( | |
| 571 startCursor, endCursor, nodesCrossed, | |
| 572 function(str, word, nodes) { | |
| 573 if (str.substr(-1) == '.') | |
| 574 return true; | |
| 575 for (var i = 0; i < nodes.length; i++) { | |
| 576 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 577 return true; | |
| 578 } | |
| 579 var style = window.getComputedStyle(nodes[i], null); | |
| 580 if (style && (style.display != 'inline' || | |
| 581 breakTags[nodes[i].tagName])) { | |
| 582 return true; | |
| 583 } | |
| 584 } | |
| 585 return false; | |
| 586 }); | |
| 587 }; | |
| 588 | |
| 589 /** | |
| 590 * Finds the previous sentence, starting from startCursor. Upon exit, | |
| 591 * startCursor and endCursor will surround the previous sentence. | |
| 592 * | |
| 593 * @param {Cursor} startCursor The position to start searching for the next | |
| 594 * sentence. On exit, will point to the start of the returned string. | |
| 595 * @param {Cursor} endCursor On exit, the end of the returned string. | |
| 596 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 597 * initial and final cursor position will be pushed onto this array. | |
| 598 * @param {Object} breakTags Associative array of tags that should break | |
| 599 * the sentence. | |
| 600 * @return {?string} The previous sentence, or null if the bottom of the | |
| 601 * document has been reached. | |
| 602 */ | |
| 603 TraverseUtil.getPreviousSentence = function( | |
| 604 startCursor, endCursor, nodesCrossed, breakTags) { | |
| 605 return TraverseUtil.getPreviousString( | |
| 606 startCursor, endCursor, nodesCrossed, | |
| 607 function(str, word, nodes) { | |
| 608 if (word.substr(-1) == '.') | |
| 609 return true; | |
| 610 for (var i = 0; i < nodes.length; i++) { | |
| 611 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 612 return true; | |
| 613 } | |
| 614 var style = window.getComputedStyle(nodes[i], null); | |
| 615 if (style && (style.display != 'inline' || | |
| 616 breakTags[nodes[i].tagName])) { | |
| 617 return true; | |
| 618 } | |
| 619 } | |
| 620 return false; | |
| 621 }); | |
| 622 }; | |
| 623 | |
| 624 /** | |
| 625 * Finds the next line, starting from endCursor. Upon exit, | |
| 626 * startCursor and endCursor will surround the next line. | |
| 627 * | |
| 628 * @param {Cursor} startCursor On exit, marks the beginning of the line. | |
| 629 * @param {Cursor} endCursor The position to start searching for the next | |
| 630 * line. On exit, will point to the end of the returned string. | |
| 631 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 632 * initial and final cursor position will be pushed onto this array. | |
| 633 * @param {number} lineLength The maximum number of characters in a line. | |
| 634 * @param {Object} breakTags Associative array of tags that should break | |
| 635 * the line. | |
| 636 * @return {?string} The next line, or null if the bottom of the | |
| 637 * document has been reached. | |
| 638 */ | |
| 639 TraverseUtil.getNextLine = function( | |
| 640 startCursor, endCursor, nodesCrossed, lineLength, breakTags) { | |
| 641 return TraverseUtil.getNextString( | |
| 642 startCursor, endCursor, nodesCrossed, | |
| 643 function(str, word, nodes) { | |
| 644 if (str.length + word.length + 1 > lineLength) | |
| 645 return true; | |
| 646 for (var i = 0; i < nodes.length; i++) { | |
| 647 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 648 return true; | |
| 649 } | |
| 650 var style = window.getComputedStyle(nodes[i], null); | |
| 651 if (style && (style.display != 'inline' || | |
| 652 breakTags[nodes[i].tagName])) { | |
| 653 return true; | |
| 654 } | |
| 655 } | |
| 656 return false; | |
| 657 }); | |
| 658 }; | |
| 659 | |
| 660 /** | |
| 661 * Finds the previous line, starting from startCursor. Upon exit, | |
| 662 * startCursor and endCursor will surround the previous line. | |
| 663 * | |
| 664 * @param {Cursor} startCursor The position to start searching for the next | |
| 665 * line. On exit, will point to the start of the returned string. | |
| 666 * @param {Cursor} endCursor On exit, the end of the returned string. | |
| 667 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 668 * initial and final cursor position will be pushed onto this array. | |
| 669 * @param {number} lineLength The maximum number of characters in a line. | |
| 670 * @param {Object} breakTags Associative array of tags that should break | |
| 671 * the sentence. | |
| 672 * @return {?string} The previous line, or null if the bottom of the | |
| 673 * document has been reached. | |
| 674 */ | |
| 675 TraverseUtil.getPreviousLine = function( | |
| 676 startCursor, endCursor, nodesCrossed, lineLength, breakTags) { | |
| 677 return TraverseUtil.getPreviousString( | |
| 678 startCursor, endCursor, nodesCrossed, | |
| 679 function(str, word, nodes) { | |
| 680 if (str.length + word.length + 1 > lineLength) | |
| 681 return true; | |
| 682 for (var i = 0; i < nodes.length; i++) { | |
| 683 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 684 return true; | |
| 685 } | |
| 686 var style = window.getComputedStyle(nodes[i], null); | |
| 687 if (style && (style.display != 'inline' || | |
| 688 breakTags[nodes[i].tagName])) { | |
| 689 return true; | |
| 690 } | |
| 691 } | |
| 692 return false; | |
| 693 }); | |
| 694 }; | |
| 695 | |
| 696 /** | |
| 697 * Finds the next paragraph, starting from endCursor. Upon exit, | |
| 698 * startCursor and endCursor will surround the next paragraph. | |
| 699 * | |
| 700 * @param {Cursor} startCursor On exit, marks the beginning of the paragraph. | |
| 701 * @param {Cursor} endCursor The position to start searching for the next | |
| 702 * paragraph. On exit, will point to the end of the returned string. | |
| 703 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 704 * initial and final cursor position will be pushed onto this array. | |
| 705 * @return {?string} The next paragraph, or null if the bottom of the | |
| 706 * document has been reached. | |
| 707 */ | |
| 708 TraverseUtil.getNextParagraph = function(startCursor, endCursor, | |
| 709 nodesCrossed) { | |
| 710 return TraverseUtil.getNextString( | |
| 711 startCursor, endCursor, nodesCrossed, | |
| 712 function(str, word, nodes) { | |
| 713 for (var i = 0; i < nodes.length; i++) { | |
| 714 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 715 return true; | |
| 716 } | |
| 717 var style = window.getComputedStyle(nodes[i], null); | |
| 718 if (style && style.display != 'inline') { | |
| 719 return true; | |
| 720 } | |
| 721 } | |
| 722 return false; | |
| 723 }); | |
| 724 }; | |
| 725 | |
| 726 /** | |
| 727 * Finds the previous paragraph, starting from startCursor. Upon exit, | |
| 728 * startCursor and endCursor will surround the previous paragraph. | |
| 729 * | |
| 730 * @param {Cursor} startCursor The position to start searching for the next | |
| 731 * paragraph. On exit, will point to the start of the returned string. | |
| 732 * @param {Cursor} endCursor On exit, the end of the returned string. | |
| 733 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 734 * initial and final cursor position will be pushed onto this array. | |
| 735 * @return {?string} The previous paragraph, or null if the bottom of the | |
| 736 * document has been reached. | |
| 737 */ | |
| 738 TraverseUtil.getPreviousParagraph = function( | |
| 739 startCursor, endCursor, nodesCrossed) { | |
| 740 return TraverseUtil.getPreviousString( | |
| 741 startCursor, endCursor, nodesCrossed, | |
| 742 function(str, word, nodes) { | |
| 743 for (var i = 0; i < nodes.length; i++) { | |
| 744 if (TraverseUtil.isSkipped(nodes[i])) { | |
| 745 return true; | |
| 746 } | |
| 747 var style = window.getComputedStyle(nodes[i], null); | |
| 748 if (style && style.display != 'inline') { | |
| 749 return true; | |
| 750 } | |
| 751 } | |
| 752 return false; | |
| 753 }); | |
| 754 }; | |
| 755 | |
| 756 /** | |
| 757 * Customizable function to return the next string of words in the DOM, based | |
| 758 * on provided functions to decide when to break one string and start | |
| 759 * the next. This can be used to get the next sentence, line, paragraph, | |
| 760 * or potentially other granularities. | |
| 761 * | |
| 762 * Finds the next contiguous string, starting from endCursor. Upon exit, | |
| 763 * startCursor and endCursor will surround the next string. | |
| 764 * | |
| 765 * The breakBefore function takes three parameters, and | |
| 766 * should return true if the string should be broken before the proposed | |
| 767 * next word: | |
| 768 * str The string so far. | |
| 769 * word The next word to be added. | |
| 770 * nodesCrossed The nodes crossed in reaching this next word. | |
| 771 * | |
| 772 * @param {Cursor} startCursor On exit, will point to the beginning of the | |
| 773 * next string. | |
| 774 * @param {Cursor} endCursor The position to start searching for the next | |
| 775 * string. On exit, will point to the end of the returned string. | |
| 776 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 777 * initial and final cursor position will be pushed onto this array. | |
| 778 * @param {function(string, string, Array.<string>)} breakBefore | |
| 779 * Function that takes the string so far, next word to be added, and | |
| 780 * nodes crossed, and returns true if the string should be ended before | |
| 781 * adding this word. | |
| 782 * @return {?string} The next string, or null if the bottom of the | |
| 783 * document has been reached. | |
| 784 */ | |
| 785 TraverseUtil.getNextString = function( | |
| 786 startCursor, endCursor, nodesCrossed, breakBefore) { | |
| 787 // Get the first word and set the start cursor to the start of the | |
| 788 // first word. | |
| 789 var wordStartCursor = endCursor.clone(); | |
| 790 var wordEndCursor = endCursor.clone(); | |
| 791 var newNodesCrossed = []; | |
| 792 var str = ''; | |
| 793 var word = TraverseUtil.getNextWord( | |
| 794 wordStartCursor, wordEndCursor, newNodesCrossed); | |
| 795 if (word == null) | |
| 796 return null; | |
| 797 startCursor.copyFrom(wordStartCursor); | |
| 798 | |
| 799 // Always add the first word when the string is empty, and then keep | |
| 800 // adding more words as long as breakBefore returns false | |
| 801 while (!str || !breakBefore(str, word, newNodesCrossed)) { | |
| 802 // Append this word, set the end cursor to the end of this word, and | |
| 803 // update the returned list of nodes crossed to include ones we crossed | |
| 804 // in reaching this word. | |
| 805 if (str) | |
| 806 str += ' '; | |
| 807 str += word; | |
| 808 nodesCrossed = nodesCrossed.concat(newNodesCrossed); | |
| 809 endCursor.copyFrom(wordEndCursor); | |
| 810 | |
| 811 // Get the next word and go back to the top of the loop. | |
| 812 newNodesCrossed = []; | |
| 813 word = TraverseUtil.getNextWord( | |
| 814 wordStartCursor, wordEndCursor, newNodesCrossed); | |
| 815 if (word == null) | |
| 816 return str; | |
| 817 } | |
| 818 | |
| 819 return str; | |
| 820 }; | |
| 821 | |
| 822 /** | |
| 823 * Customizable function to return the previous string of words in the DOM, | |
| 824 * based on provided functions to decide when to break one string and start | |
| 825 * the next. See getNextString, above, for more details. | |
| 826 * | |
| 827 * Finds the previous contiguous string, starting from startCursor. Upon exit, | |
| 828 * startCursor and endCursor will surround the next string. | |
| 829 * | |
| 830 * @param {Cursor} startCursor The position to start searching for the | |
| 831 * previous string. On exit, will point to the beginning of the | |
| 832 * string returned. | |
| 833 * @param {Cursor} endCursor On exit, will point to the end of the | |
| 834 * string returned. | |
| 835 * @param {Array.<Node>} nodesCrossed Any HTML nodes crossed between the | |
| 836 * initial and final cursor position will be pushed onto this array. | |
| 837 * @param {function(string, string, Array.<string>)} breakBefore | |
| 838 * Function that takes the string so far, the word to be added, and | |
| 839 * nodes crossed, and returns true if the string should be ended before | |
| 840 * adding this word. | |
| 841 * @return {?string} The next string, or null if the top of the | |
| 842 * document has been reached. | |
| 843 */ | |
| 844 TraverseUtil.getPreviousString = function( | |
| 845 startCursor, endCursor, nodesCrossed, breakBefore) { | |
| 846 // Get the first word and set the end cursor to the end of the | |
| 847 // first word. | |
| 848 var wordStartCursor = startCursor.clone(); | |
| 849 var wordEndCursor = startCursor.clone(); | |
| 850 var newNodesCrossed = []; | |
| 851 var str = ''; | |
| 852 var word = TraverseUtil.getPreviousWord( | |
| 853 wordStartCursor, wordEndCursor, newNodesCrossed); | |
| 854 if (word == null) | |
| 855 return null; | |
| 856 endCursor.copyFrom(wordEndCursor); | |
| 857 | |
| 858 // Always add the first word when the string is empty, and then keep | |
| 859 // adding more words as long as breakBefore returns false | |
| 860 while (!str || !breakBefore(str, word, newNodesCrossed)) { | |
| 861 // Prepend this word, set the start cursor to the start of this word, and | |
| 862 // update the returned list of nodes crossed to include ones we crossed | |
| 863 // in reaching this word. | |
| 864 if (str) | |
| 865 str = ' ' + str; | |
| 866 str = word + str; | |
| 867 nodesCrossed = nodesCrossed.concat(newNodesCrossed); | |
| 868 startCursor.copyFrom(wordStartCursor); | |
| 869 v | |
| 870 // Get the previous word and go back to the top of the loop. | |
| 871 newNodesCrossed = []; | |
| 872 word = TraverseUtil.getPreviousWord( | |
| 873 wordStartCursor, wordEndCursor, newNodesCrossed); | |
| 874 if (word == null) | |
| 875 return str; | |
| 876 } | |
| 877 | |
| 878 return str; | |
| 879 }; | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 606653005:
Revert "Initial checkin of accessibility extensions." (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master