OLD | NEW |
(Empty) | |
| 1 // Copyright 2006 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 |
| 12 // implied. See the License for the specific language governing |
| 13 // permissions and limitations under the License. |
| 14 /** |
| 15 * Author: Steffen Meschkat <mesch@google.com> |
| 16 * |
| 17 * @fileoverview A simple formatter to project JavaScript data into |
| 18 * HTML templates. The template is edited in place. I.e. in order to |
| 19 * instantiate a template, clone it from the DOM first, and then |
| 20 * process the cloned template. This allows for updating of templates: |
| 21 * If the templates is processed again, changed values are merely |
| 22 * updated. |
| 23 * |
| 24 * NOTE(mesch): IE DOM doesn't have importNode(). |
| 25 * |
| 26 * NOTE(mesch): The property name "length" must not be used in input |
| 27 * data, see comment in jstSelect_(). |
| 28 */ |
| 29 |
| 30 |
| 31 /** |
| 32 * Names of jstemplate attributes. These attributes are attached to |
| 33 * normal HTML elements and bind expression context data to the HTML |
| 34 * fragment that is used as template. |
| 35 */ |
| 36 var ATT_select = 'jsselect'; |
| 37 var ATT_instance = 'jsinstance'; |
| 38 var ATT_display = 'jsdisplay'; |
| 39 var ATT_values = 'jsvalues'; |
| 40 var ATT_vars = 'jsvars'; |
| 41 var ATT_eval = 'jseval'; |
| 42 var ATT_transclude = 'transclude'; |
| 43 var ATT_content = 'jscontent'; |
| 44 var ATT_skip = 'jsskip'; |
| 45 |
| 46 |
| 47 /** |
| 48 * Name of the attribute that caches a reference to the parsed |
| 49 * template processing attribute values on a template node. |
| 50 */ |
| 51 var ATT_jstcache = 'jstcache'; |
| 52 |
| 53 |
| 54 /** |
| 55 * Name of the property that caches the parsed template processing |
| 56 * attribute values on a template node. |
| 57 */ |
| 58 var PROP_jstcache = '__jstcache'; |
| 59 |
| 60 |
| 61 /** |
| 62 * ID of the element that contains dynamically loaded jstemplates. |
| 63 */ |
| 64 var STRING_jsts = 'jsts'; |
| 65 |
| 66 |
| 67 /** |
| 68 * Un-inlined string literals, to avoid object creation in |
| 69 * IE6. |
| 70 */ |
| 71 var CHAR_asterisk = '*'; |
| 72 var CHAR_dollar = '$'; |
| 73 var CHAR_period = '.'; |
| 74 var CHAR_ampersand = '&'; |
| 75 var STRING_div = 'div'; |
| 76 var STRING_id = 'id'; |
| 77 var STRING_asteriskzero = '*0'; |
| 78 var STRING_zero = '0'; |
| 79 |
| 80 |
| 81 /** |
| 82 * HTML template processor. Data values are bound to HTML templates |
| 83 * using the attributes transclude, jsselect, jsdisplay, jscontent, |
| 84 * jsvalues. The template is modifed in place. The values of those |
| 85 * attributes are JavaScript expressions that are evaluated in the |
| 86 * context of the data object fragment. |
| 87 * |
| 88 * @param {JsEvalContext} context Context created from the input data |
| 89 * object. |
| 90 * |
| 91 * @param {Element} template DOM node of the template. This will be |
| 92 * processed in place. After processing, it will still be a valid |
| 93 * template that, if processed again with the same data, will remain |
| 94 * unchanged. |
| 95 * |
| 96 * @param {boolean} opt_debugging Optional flag to collect debugging |
| 97 * information while processing the template. Only takes effect |
| 98 * in MAPS_DEBUG. |
| 99 */ |
| 100 function jstProcess(context, template, opt_debugging) { |
| 101 var processor = new JstProcessor; |
| 102 if (MAPS_DEBUG && opt_debugging) { |
| 103 processor.setDebugging(opt_debugging); |
| 104 } |
| 105 JstProcessor.prepareTemplate_(template); |
| 106 |
| 107 /** |
| 108 * Caches the document of the template node, so we don't have to |
| 109 * access it through ownerDocument. |
| 110 * @type Document |
| 111 */ |
| 112 processor.document_ = ownerDocument(template); |
| 113 |
| 114 processor.run_(bindFully(processor, processor.jstProcessOuter_, |
| 115 context, template)); |
| 116 if (MAPS_DEBUG && opt_debugging) { |
| 117 log('jstProcess:' + '\n' + processor.getLogs().join('\n')); |
| 118 } |
| 119 } |
| 120 |
| 121 |
| 122 /** |
| 123 * Internal class used by jstemplates to maintain context. This is |
| 124 * necessary to process deep templates in Safari which has a |
| 125 * relatively shallow maximum recursion depth of 100. |
| 126 * @class |
| 127 * @constructor |
| 128 */ |
| 129 function JstProcessor() { |
| 130 if (MAPS_DEBUG) { |
| 131 /** |
| 132 * An array of logging messages. These are collected during processing |
| 133 * and dumped to the console at the end. |
| 134 * @type Array.<string> |
| 135 */ |
| 136 this.logs_ = []; |
| 137 } |
| 138 } |
| 139 |
| 140 |
| 141 /** |
| 142 * Counter to generate node ids. These ids will be stored in |
| 143 * ATT_jstcache and be used to lookup the preprocessed js attributes |
| 144 * from the jstcache_. The id is stored in an attribute so it |
| 145 * suvives cloneNode() and thus cloned template nodes can share the |
| 146 * same cache entry. |
| 147 * @type number |
| 148 */ |
| 149 JstProcessor.jstid_ = 0; |
| 150 |
| 151 |
| 152 /** |
| 153 * Map from jstid to processed js attributes. |
| 154 * @type Object |
| 155 */ |
| 156 JstProcessor.jstcache_ = {}; |
| 157 |
| 158 /** |
| 159 * The neutral cache entry. Used for all nodes that don't have any |
| 160 * jst attributes. We still set the jsid attribute on those nodes so |
| 161 * we can avoid to look again for all the other jst attributes that |
| 162 * aren't there. Remember: not only the processing of the js |
| 163 * attribute values is expensive and we thus want to cache it. The |
| 164 * access to the attributes on the Node in the first place is |
| 165 * expensive too. |
| 166 */ |
| 167 JstProcessor.jstcache_[0] = {}; |
| 168 |
| 169 |
| 170 /** |
| 171 * Map from concatenated attribute string to jstid. |
| 172 * The key is the concatenation of all jst atributes found on a node |
| 173 * formatted as "name1=value1&name2=value2&...", in the order defined by |
| 174 * JST_ATTRIBUTES. The value is the id of the jstcache_ entry that can |
| 175 * be used for this node. This allows the reuse of cache entries in cases |
| 176 * when a cached entry already exists for a given combination of attribute |
| 177 * values. (For example when two different nodes in a template share the same |
| 178 * JST attributes.) |
| 179 * @type Object |
| 180 */ |
| 181 JstProcessor.jstcacheattributes_ = {}; |
| 182 |
| 183 |
| 184 /** |
| 185 * Map for storing temporary attribute values in prepareNode_() so they don't |
| 186 * have to be retrieved twice. (IE6 perf) |
| 187 * @type Object |
| 188 */ |
| 189 JstProcessor.attributeValues_ = {}; |
| 190 |
| 191 |
| 192 /** |
| 193 * A list for storing non-empty attributes found on a node in prepareNode_(). |
| 194 * The array is global since it can be reused - this way there is no need to |
| 195 * construct a new array object for each invocation. (IE6 perf) |
| 196 * @type Array |
| 197 */ |
| 198 JstProcessor.attributeList_ = []; |
| 199 |
| 200 |
| 201 /** |
| 202 * Prepares the template: preprocesses all jstemplate attributes. |
| 203 * |
| 204 * @param {Element} template |
| 205 */ |
| 206 JstProcessor.prepareTemplate_ = function(template) { |
| 207 if (!template[PROP_jstcache]) { |
| 208 domTraverseElements(template, function(node) { |
| 209 JstProcessor.prepareNode_(node); |
| 210 }); |
| 211 } |
| 212 }; |
| 213 |
| 214 |
| 215 /** |
| 216 * A list of attributes we use to specify jst processing instructions, |
| 217 * and the functions used to parse their values. |
| 218 * |
| 219 * @type Array.<Array> |
| 220 */ |
| 221 var JST_ATTRIBUTES = [ |
| 222 [ ATT_select, jsEvalToFunction ], |
| 223 [ ATT_display, jsEvalToFunction ], |
| 224 [ ATT_values, jsEvalToValues ], |
| 225 [ ATT_vars, jsEvalToValues ], |
| 226 [ ATT_eval, jsEvalToExpressions ], |
| 227 [ ATT_transclude, jsEvalToSelf ], |
| 228 [ ATT_content, jsEvalToFunction ], |
| 229 [ ATT_skip, jsEvalToFunction ] |
| 230 ]; |
| 231 |
| 232 |
| 233 /** |
| 234 * Prepares a single node: preprocesses all template attributes of the |
| 235 * node, and if there are any, assigns a jsid attribute and stores the |
| 236 * preprocessed attributes under the jsid in the jstcache. |
| 237 * |
| 238 * @param {Element} node |
| 239 * |
| 240 * @return {Object} The jstcache entry. The processed jst attributes |
| 241 * are properties of this object. If the node has no jst attributes, |
| 242 * returns an object with no properties (the jscache_[0] entry). |
| 243 */ |
| 244 JstProcessor.prepareNode_ = function(node) { |
| 245 // If the node already has a cache property, return it. |
| 246 if (node[PROP_jstcache]) { |
| 247 return node[PROP_jstcache]; |
| 248 } |
| 249 |
| 250 // If it is not found, we always set the PROP_jstcache property on the node. |
| 251 // Accessing the property is faster than executing getAttribute(). If we |
| 252 // don't find the property on a node that was cloned in jstSelect_(), we |
| 253 // will fall back to check for the attribute and set the property |
| 254 // from cache. |
| 255 |
| 256 // If the node has an attribute indexing a cache object, set it as a property |
| 257 // and return it. |
| 258 var jstid = domGetAttribute(node, ATT_jstcache); |
| 259 if (jstid != null) { |
| 260 return node[PROP_jstcache] = JstProcessor.jstcache_[jstid]; |
| 261 } |
| 262 |
| 263 var attributeValues = JstProcessor.attributeValues_; |
| 264 var attributeList = JstProcessor.attributeList_; |
| 265 attributeList.length = 0; |
| 266 |
| 267 // Look for interesting attributes. |
| 268 for (var i = 0, I = jsLength(JST_ATTRIBUTES); i < I; ++i) { |
| 269 var name = JST_ATTRIBUTES[i][0]; |
| 270 var value = domGetAttribute(node, name); |
| 271 attributeValues[name] = value; |
| 272 if (value != null) { |
| 273 attributeList.push(name + "=" + value); |
| 274 } |
| 275 } |
| 276 |
| 277 // If none found, mark this node to prevent further inspection, and return |
| 278 // an empty cache object. |
| 279 if (attributeList.length == 0) { |
| 280 domSetAttribute(node, ATT_jstcache, STRING_zero); |
| 281 return node[PROP_jstcache] = JstProcessor.jstcache_[0]; |
| 282 } |
| 283 |
| 284 // If we already have a cache object corresponding to these attributes, |
| 285 // annotate the node with it, and return it. |
| 286 var attstring = attributeList.join(CHAR_ampersand); |
| 287 if (jstid = JstProcessor.jstcacheattributes_[attstring]) { |
| 288 domSetAttribute(node, ATT_jstcache, jstid); |
| 289 return node[PROP_jstcache] = JstProcessor.jstcache_[jstid]; |
| 290 } |
| 291 |
| 292 // Otherwise, build a new cache object. |
| 293 var jstcache = {}; |
| 294 for (var i = 0, I = jsLength(JST_ATTRIBUTES); i < I; ++i) { |
| 295 var att = JST_ATTRIBUTES[i]; |
| 296 var name = att[0]; |
| 297 var parse = att[1]; |
| 298 var value = attributeValues[name]; |
| 299 if (value != null) { |
| 300 jstcache[name] = parse(value); |
| 301 if (MAPS_DEBUG) { |
| 302 jstcache.jstAttributeValues = jstcache.jstAttributeValues || {}; |
| 303 jstcache.jstAttributeValues[name] = value; |
| 304 } |
| 305 } |
| 306 } |
| 307 |
| 308 jstid = STRING_empty + ++JstProcessor.jstid_; |
| 309 domSetAttribute(node, ATT_jstcache, jstid); |
| 310 JstProcessor.jstcache_[jstid] = jstcache; |
| 311 JstProcessor.jstcacheattributes_[attstring] = jstid; |
| 312 |
| 313 return node[PROP_jstcache] = jstcache; |
| 314 }; |
| 315 |
| 316 |
| 317 /** |
| 318 * Runs the given function in our state machine. |
| 319 * |
| 320 * It's informative to view the set of all function calls as a tree: |
| 321 * - nodes are states |
| 322 * - edges are state transitions, implemented as calls to the pending |
| 323 * functions in the stack. |
| 324 * - pre-order function calls are downward edges (recursion into call). |
| 325 * - post-order function calls are upward edges (return from call). |
| 326 * - leaves are nodes which do not recurse. |
| 327 * We represent the call tree as an array of array of calls, indexed as |
| 328 * stack[depth][index]. Here [depth] indexes into the call stack, and |
| 329 * [index] indexes into the call queue at that depth. We require a call |
| 330 * queue so that a node may branch to more than one child |
| 331 * (which will be called serially), typically due to a loop structure. |
| 332 * |
| 333 * @param {Function} f The first function to run. |
| 334 */ |
| 335 JstProcessor.prototype.run_ = function(f) { |
| 336 var me = this; |
| 337 |
| 338 /** |
| 339 * A stack of queues of pre-order calls. |
| 340 * The inner arrays (constituent queues) are structured as |
| 341 * [ arg2, arg1, method, arg2, arg1, method, ...] |
| 342 * ie. a flattened array of methods with 2 arguments, in reverse order |
| 343 * for efficient push/pop. |
| 344 * |
| 345 * The outer array is a stack of such queues. |
| 346 * |
| 347 * @type Array.<Array> |
| 348 */ |
| 349 var calls = me.calls_ = []; |
| 350 |
| 351 /** |
| 352 * The index into the queue for each depth. NOTE: Alternative would |
| 353 * be to maintain the queues in reverse order (popping off of the |
| 354 * end) but the repeated calls to .pop() consumed 90% of this |
| 355 * function's execution time. |
| 356 * @type Array.<number> |
| 357 */ |
| 358 var queueIndices = me.queueIndices_ = []; |
| 359 |
| 360 /** |
| 361 * A pool of empty arrays. Minimizes object allocation for IE6's benefit. |
| 362 * @type Array.<Array> |
| 363 */ |
| 364 var arrayPool = me.arrayPool_ = []; |
| 365 |
| 366 f(); |
| 367 var queue, queueIndex; |
| 368 var method, arg1, arg2; |
| 369 var temp; |
| 370 while (calls.length) { |
| 371 queue = calls[calls.length - 1]; |
| 372 queueIndex = queueIndices[queueIndices.length - 1]; |
| 373 if (queueIndex >= queue.length) { |
| 374 me.recycleArray_(calls.pop()); |
| 375 queueIndices.pop(); |
| 376 continue; |
| 377 } |
| 378 |
| 379 // Run the first function in the queue. |
| 380 method = queue[queueIndex++]; |
| 381 arg1 = queue[queueIndex++]; |
| 382 arg2 = queue[queueIndex++]; |
| 383 queueIndices[queueIndices.length - 1] = queueIndex; |
| 384 method.call(me, arg1, arg2); |
| 385 } |
| 386 }; |
| 387 |
| 388 |
| 389 /** |
| 390 * Pushes one or more functions onto the stack. These will be run in sequence, |
| 391 * interspersed with any recursive calls that they make. |
| 392 * |
| 393 * This method takes ownership of the given array! |
| 394 * |
| 395 * @param {Array} args Array of method calls structured as |
| 396 * [ method, arg1, arg2, method, arg1, arg2, ... ] |
| 397 */ |
| 398 JstProcessor.prototype.push_ = function(args) { |
| 399 this.calls_.push(args); |
| 400 this.queueIndices_.push(0); |
| 401 }; |
| 402 |
| 403 |
| 404 /** |
| 405 * Enable/disable debugging. |
| 406 * @param {boolean} debugging New state |
| 407 */ |
| 408 JstProcessor.prototype.setDebugging = function(debugging) { |
| 409 if (MAPS_DEBUG) { |
| 410 this.debugging_ = debugging; |
| 411 } |
| 412 }; |
| 413 |
| 414 |
| 415 JstProcessor.prototype.createArray_ = function() { |
| 416 if (this.arrayPool_.length) { |
| 417 return this.arrayPool_.pop(); |
| 418 } else { |
| 419 return []; |
| 420 } |
| 421 }; |
| 422 |
| 423 |
| 424 JstProcessor.prototype.recycleArray_ = function(array) { |
| 425 arrayClear(array); |
| 426 this.arrayPool_.push(array); |
| 427 }; |
| 428 |
| 429 /** |
| 430 * Implements internals of jstProcess. This processes the two |
| 431 * attributes transclude and jsselect, which replace or multiply |
| 432 * elements, hence the name "outer". The remainder of the attributes |
| 433 * is processed in jstProcessInner_(), below. That function |
| 434 * jsProcessInner_() only processes attributes that affect an existing |
| 435 * node, but doesn't create or destroy nodes, hence the name |
| 436 * "inner". jstProcessInner_() is called through jstSelect_() if there |
| 437 * is a jsselect attribute (possibly for newly created clones of the |
| 438 * current template node), or directly from here if there is none. |
| 439 * |
| 440 * @param {JsEvalContext} context |
| 441 * |
| 442 * @param {Element} template |
| 443 */ |
| 444 JstProcessor.prototype.jstProcessOuter_ = function(context, template) { |
| 445 var me = this; |
| 446 |
| 447 var jstAttributes = me.jstAttributes_(template); |
| 448 if (MAPS_DEBUG && me.debugging_) { |
| 449 me.logState_('Outer', template, jstAttributes.jstAttributeValues); |
| 450 } |
| 451 |
| 452 var transclude = jstAttributes[ATT_transclude]; |
| 453 if (transclude) { |
| 454 var tr = jstGetTemplate(transclude); |
| 455 if (tr) { |
| 456 domReplaceChild(tr, template); |
| 457 var call = me.createArray_(); |
| 458 call.push(me.jstProcessOuter_, context, tr); |
| 459 me.push_(call); |
| 460 } else { |
| 461 domRemoveNode(template); |
| 462 } |
| 463 return; |
| 464 } |
| 465 |
| 466 var select = jstAttributes[ATT_select]; |
| 467 if (select) { |
| 468 me.jstSelect_(context, template, select); |
| 469 } else { |
| 470 me.jstProcessInner_(context, template); |
| 471 } |
| 472 }; |
| 473 |
| 474 |
| 475 /** |
| 476 * Implements internals of jstProcess. This processes all attributes |
| 477 * except transclude and jsselect. It is called either from |
| 478 * jstSelect_() for nodes that have a jsselect attribute so that the |
| 479 * jsselect attribute will not be processed again, or else directly |
| 480 * from jstProcessOuter_(). See the comment on jstProcessOuter_() for |
| 481 * an explanation of the name. |
| 482 * |
| 483 * @param {JsEvalContext} context |
| 484 * |
| 485 * @param {Element} template |
| 486 */ |
| 487 JstProcessor.prototype.jstProcessInner_ = function(context, template) { |
| 488 var me = this; |
| 489 |
| 490 var jstAttributes = me.jstAttributes_(template); |
| 491 if (MAPS_DEBUG && me.debugging_) { |
| 492 me.logState_('Inner', template, jstAttributes.jstAttributeValues); |
| 493 } |
| 494 |
| 495 // NOTE(mesch): See NOTE on ATT_content why this is a separate |
| 496 // attribute, and not a special value in ATT_values. |
| 497 var display = jstAttributes[ATT_display]; |
| 498 if (display) { |
| 499 var shouldDisplay = context.jsexec(display, template); |
| 500 if (MAPS_DEBUG && me.debugging_) { |
| 501 me.logs_.push(ATT_display + ': ' + shouldDisplay + '<br/>'); |
| 502 } |
| 503 if (!shouldDisplay) { |
| 504 displayNone(template); |
| 505 return; |
| 506 } |
| 507 displayDefault(template); |
| 508 } |
| 509 |
| 510 // NOTE(mesch): jsvars is evaluated before jsvalues, because it's |
| 511 // more useful to be able to use var values in attribute value |
| 512 // expressions than vice versa. |
| 513 var values = jstAttributes[ATT_vars]; |
| 514 if (values) { |
| 515 me.jstVars_(context, template, values); |
| 516 } |
| 517 |
| 518 values = jstAttributes[ATT_values]; |
| 519 if (values) { |
| 520 me.jstValues_(context, template, values); |
| 521 } |
| 522 |
| 523 // Evaluate expressions immediately. Useful for hooking callbacks |
| 524 // into jstemplates. |
| 525 // |
| 526 // NOTE(mesch): Evaluation order is sometimes significant, e.g. when |
| 527 // the expression evaluated in jseval relies on the values set in |
| 528 // jsvalues, so it needs to be evaluated *after* |
| 529 // jsvalues. TODO(mesch): This is quite arbitrary, it would be |
| 530 // better if this would have more necessity to it. |
| 531 var expressions = jstAttributes[ATT_eval]; |
| 532 if (expressions) { |
| 533 for (var i = 0, I = jsLength(expressions); i < I; ++i) { |
| 534 context.jsexec(expressions[i], template); |
| 535 } |
| 536 } |
| 537 |
| 538 var skip = jstAttributes[ATT_skip]; |
| 539 if (skip) { |
| 540 var shouldSkip = context.jsexec(skip, template); |
| 541 if (MAPS_DEBUG && me.debugging_) { |
| 542 me.logs_.push(ATT_skip + ': ' + shouldSkip + '<br/>'); |
| 543 } |
| 544 if (shouldSkip) return; |
| 545 } |
| 546 |
| 547 // NOTE(mesch): content is a separate attribute, instead of just a |
| 548 // special value mentioned in values, for two reasons: (1) it is |
| 549 // fairly common to have only mapped content, and writing |
| 550 // content="expr" is shorter than writing values="content:expr", and |
| 551 // (2) the presence of content actually terminates traversal, and we |
| 552 // need to check for that. Display is a separate attribute for a |
| 553 // reason similar to the second, in that its presence *may* |
| 554 // terminate traversal. |
| 555 var content = jstAttributes[ATT_content]; |
| 556 if (content) { |
| 557 me.jstContent_(context, template, content); |
| 558 |
| 559 } else { |
| 560 // Newly generated children should be ignored, so we explicitly |
| 561 // store the children to be processed. |
| 562 var queue = me.createArray_(); |
| 563 for (var c = template.firstChild; c; c = c.nextSibling) { |
| 564 if (c.nodeType == DOM_ELEMENT_NODE) { |
| 565 queue.push(me.jstProcessOuter_, context, c); |
| 566 } |
| 567 } |
| 568 if (queue.length) me.push_(queue); |
| 569 } |
| 570 }; |
| 571 |
| 572 |
| 573 /** |
| 574 * Implements the jsselect attribute: evalutes the value of the |
| 575 * jsselect attribute in the current context, with the current |
| 576 * variable bindings (see JsEvalContext.jseval()). If the value is an |
| 577 * array, the current template node is multiplied once for every |
| 578 * element in the array, with the array element being the context |
| 579 * object. If the array is empty, or the value is undefined, then the |
| 580 * current template node is dropped. If the value is not an array, |
| 581 * then it is just made the context object. |
| 582 * |
| 583 * @param {JsEvalContext} context The current evaluation context. |
| 584 * |
| 585 * @param {Element} template The currently processed node of the template. |
| 586 * |
| 587 * @param {Function} select The javascript expression to evaluate. |
| 588 * |
| 589 * @notypecheck FIXME(hmitchell): See OCL6434950. instance and value need |
| 590 * type checks. |
| 591 */ |
| 592 JstProcessor.prototype.jstSelect_ = function(context, template, select) { |
| 593 var me = this; |
| 594 |
| 595 var value = context.jsexec(select, template); |
| 596 |
| 597 // Enable reprocessing: if this template is reprocessed, then only |
| 598 // fill the section instance here. Otherwise do the cardinal |
| 599 // processing of a new template. |
| 600 var instance = domGetAttribute(template, ATT_instance); |
| 601 |
| 602 var instanceLast = false; |
| 603 if (instance) { |
| 604 if (instance.charAt(0) == CHAR_asterisk) { |
| 605 instance = parseInt10(instance.substr(1)); |
| 606 instanceLast = true; |
| 607 } else { |
| 608 instance = parseInt10(/** @type string */(instance)); |
| 609 } |
| 610 } |
| 611 |
| 612 // The expression value instanceof Array is occasionally false for |
| 613 // arrays, seen in Firefox. Thus we recognize an array as an object |
| 614 // which is not null that has a length property. Notice that this |
| 615 // also matches input data with a length property, so this property |
| 616 // name should be avoided in input data. |
| 617 var multiple = isArray(value); |
| 618 var count = multiple ? jsLength(value) : 1; |
| 619 var multipleEmpty = (multiple && count == 0); |
| 620 |
| 621 if (multiple) { |
| 622 if (multipleEmpty) { |
| 623 // For an empty array, keep the first template instance and mark |
| 624 // it last. Remove all other template instances. |
| 625 if (!instance) { |
| 626 domSetAttribute(template, ATT_instance, STRING_asteriskzero); |
| 627 displayNone(template); |
| 628 } else { |
| 629 domRemoveNode(template); |
| 630 } |
| 631 |
| 632 } else { |
| 633 displayDefault(template); |
| 634 // For a non empty array, create as many template instances as |
| 635 // are needed. If the template is first processed, as many |
| 636 // template instances are needed as there are values in the |
| 637 // array. If the template is reprocessed, new template instances |
| 638 // are only needed if there are more array values than template |
| 639 // instances. Those additional instances are created by |
| 640 // replicating the last template instance. |
| 641 // |
| 642 // When the template is first processed, there is no jsinstance |
| 643 // attribute. This is indicated by instance === null, except in |
| 644 // opera it is instance === "". Notice also that the === is |
| 645 // essential, because 0 == "", presumably via type coercion to |
| 646 // boolean. |
| 647 if (instance === null || instance === STRING_empty || |
| 648 (instanceLast && instance < count - 1)) { |
| 649 // A queue of calls to push. |
| 650 var queue = me.createArray_(); |
| 651 |
| 652 var instancesStart = instance || 0; |
| 653 var i, I, clone; |
| 654 for (i = instancesStart, I = count - 1; i < I; ++i) { |
| 655 var node = domCloneNode(template); |
| 656 domInsertBefore(node, template); |
| 657 |
| 658 jstSetInstance(/** @type Element */(node), value, i); |
| 659 clone = context.clone(value[i], i, count); |
| 660 |
| 661 queue.push(me.jstProcessInner_, clone, node, |
| 662 JsEvalContext.recycle, clone, null); |
| 663 |
| 664 } |
| 665 // Push the originally present template instance last to keep |
| 666 // the order aligned with the DOM order, because the newly |
| 667 // created template instances are inserted *before* the |
| 668 // original instance. |
| 669 jstSetInstance(template, value, i); |
| 670 clone = context.clone(value[i], i, count); |
| 671 queue.push(me.jstProcessInner_, clone, template, |
| 672 JsEvalContext.recycle, clone, null); |
| 673 me.push_(queue); |
| 674 } else if (instance < count) { |
| 675 var v = value[instance]; |
| 676 |
| 677 jstSetInstance(template, value, instance); |
| 678 var clone = context.clone(v, instance, count); |
| 679 var queue = me.createArray_(); |
| 680 queue.push(me.jstProcessInner_, clone, template, |
| 681 JsEvalContext.recycle, clone, null); |
| 682 me.push_(queue); |
| 683 } else { |
| 684 domRemoveNode(template); |
| 685 } |
| 686 } |
| 687 } else { |
| 688 if (value == null) { |
| 689 displayNone(template); |
| 690 } else { |
| 691 displayDefault(template); |
| 692 var clone = context.clone(value, 0, 1); |
| 693 var queue = me.createArray_(); |
| 694 queue.push(me.jstProcessInner_, clone, template, |
| 695 JsEvalContext.recycle, clone, null); |
| 696 me.push_(queue); |
| 697 } |
| 698 } |
| 699 }; |
| 700 |
| 701 |
| 702 /** |
| 703 * Implements the jsvars attribute: evaluates each of the values and |
| 704 * assigns them to variables in the current context. Similar to |
| 705 * jsvalues, except that all values are treated as vars, independent |
| 706 * of their names. |
| 707 * |
| 708 * @param {JsEvalContext} context Current evaluation context. |
| 709 * |
| 710 * @param {Element} template Currently processed template node. |
| 711 * |
| 712 * @param {Array} values Processed value of the jsvalues attribute: a |
| 713 * flattened array of pairs. The second element in the pair is a |
| 714 * function that can be passed to jsexec() for evaluation in the |
| 715 * current jscontext, and the first element is the variable name that |
| 716 * the value returned by jsexec is assigned to. |
| 717 */ |
| 718 JstProcessor.prototype.jstVars_ = function(context, template, values) { |
| 719 for (var i = 0, I = jsLength(values); i < I; i += 2) { |
| 720 var label = values[i]; |
| 721 var value = context.jsexec(values[i+1], template); |
| 722 context.setVariable(label, value); |
| 723 } |
| 724 }; |
| 725 |
| 726 |
| 727 /** |
| 728 * Implements the jsvalues attribute: evaluates each of the values and |
| 729 * assigns them to variables in the current context (if the name |
| 730 * starts with '$', javascript properties of the current template node |
| 731 * (if the name starts with '.'), or DOM attributes of the current |
| 732 * template node (otherwise). Since DOM attribute values are always |
| 733 * strings, the value is coerced to string in the latter case, |
| 734 * otherwise it's the uncoerced javascript value. |
| 735 * |
| 736 * @param {JsEvalContext} context Current evaluation context. |
| 737 * |
| 738 * @param {Element} template Currently processed template node. |
| 739 * |
| 740 * @param {Array} values Processed value of the jsvalues attribute: a |
| 741 * flattened array of pairs. The second element in the pair is a |
| 742 * function that can be passed to jsexec() for evaluation in the |
| 743 * current jscontext, and the first element is the label that |
| 744 * determines where the value returned by jsexec is assigned to. |
| 745 */ |
| 746 JstProcessor.prototype.jstValues_ = function(context, template, values) { |
| 747 for (var i = 0, I = jsLength(values); i < I; i += 2) { |
| 748 var label = values[i]; |
| 749 var value = context.jsexec(values[i+1], template); |
| 750 |
| 751 if (label.charAt(0) == CHAR_dollar) { |
| 752 // A jsvalues entry whose name starts with $ sets a local |
| 753 // variable. |
| 754 context.setVariable(label, value); |
| 755 |
| 756 } else if (label.charAt(0) == CHAR_period) { |
| 757 // A jsvalues entry whose name starts with . sets a property of |
| 758 // the current template node. The name may have further dot |
| 759 // separated components, which are translated into namespace |
| 760 // objects. This specifically allows to set properties on .style |
| 761 // using jsvalues. NOTE(mesch): Setting the style attribute has |
| 762 // no effect in IE and hence should not be done anyway. |
| 763 var nameSpaceLabel = label.substr(1).split(CHAR_period); |
| 764 var nameSpaceObject = template; |
| 765 var nameSpaceDepth = jsLength(nameSpaceLabel); |
| 766 for (var j = 0, J = nameSpaceDepth - 1; j < J; ++j) { |
| 767 var jLabel = nameSpaceLabel[j]; |
| 768 if (!nameSpaceObject[jLabel]) { |
| 769 nameSpaceObject[jLabel] = {}; |
| 770 } |
| 771 nameSpaceObject = nameSpaceObject[jLabel]; |
| 772 } |
| 773 nameSpaceObject[nameSpaceLabel[nameSpaceDepth - 1]] = value; |
| 774 |
| 775 } else if (label) { |
| 776 // Any other jsvalues entry sets an attribute of the current |
| 777 // template node. |
| 778 if (typeof value == TYPE_boolean) { |
| 779 // Handle boolean values that are set as attributes specially, |
| 780 // according to the XML/HTML convention. |
| 781 if (value) { |
| 782 domSetAttribute(template, label, label); |
| 783 } else { |
| 784 domRemoveAttribute(template, label); |
| 785 } |
| 786 } else { |
| 787 domSetAttribute(template, label, STRING_empty + value); |
| 788 } |
| 789 } |
| 790 } |
| 791 }; |
| 792 |
| 793 |
| 794 /** |
| 795 * Implements the jscontent attribute. Evalutes the expression in |
| 796 * jscontent in the current context and with the current variables, |
| 797 * and assigns its string value to the content of the current template |
| 798 * node. |
| 799 * |
| 800 * @param {JsEvalContext} context Current evaluation context. |
| 801 * |
| 802 * @param {Element} template Currently processed template node. |
| 803 * |
| 804 * @param {Function} content Processed value of the jscontent |
| 805 * attribute. |
| 806 */ |
| 807 JstProcessor.prototype.jstContent_ = function(context, template, content) { |
| 808 // NOTE(mesch): Profiling shows that this method costs significant |
| 809 // time. In jstemplate_perf.html, it's about 50%. I tried to replace |
| 810 // by HTML escaping and assignment to innerHTML, but that was even |
| 811 // slower. |
| 812 var value = STRING_empty + context.jsexec(content, template); |
| 813 // Prevent flicker when refreshing a template and the value doesn't |
| 814 // change. |
| 815 if (template.innerHTML == value) { |
| 816 return; |
| 817 } |
| 818 while (template.firstChild) { |
| 819 domRemoveNode(template.firstChild); |
| 820 } |
| 821 var t = domCreateTextNode(this.document_, value); |
| 822 domAppendChild(template, t); |
| 823 }; |
| 824 |
| 825 |
| 826 /** |
| 827 * Caches access to and parsing of template processing attributes. If |
| 828 * domGetAttribute() is called every time a template attribute value |
| 829 * is used, it takes more than 10% of the time. |
| 830 * |
| 831 * @param {Element} template A DOM element node of the template. |
| 832 * |
| 833 * @return {Object} A javascript object that has all js template |
| 834 * processing attribute values of the node as properties. |
| 835 */ |
| 836 JstProcessor.prototype.jstAttributes_ = function(template) { |
| 837 if (template[PROP_jstcache]) { |
| 838 return template[PROP_jstcache]; |
| 839 } |
| 840 |
| 841 var jstid = domGetAttribute(template, ATT_jstcache); |
| 842 if (jstid) { |
| 843 return template[PROP_jstcache] = JstProcessor.jstcache_[jstid]; |
| 844 } |
| 845 |
| 846 return JstProcessor.prepareNode_(template); |
| 847 }; |
| 848 |
| 849 |
| 850 /** |
| 851 * Helps to implement the transclude attribute, and is the initial |
| 852 * call to get hold of a template from its ID. |
| 853 * |
| 854 * If the ID is not present in the DOM, and opt_loadHtmlFn is specified, this |
| 855 * function will call that function and add the result to the DOM, before |
| 856 * returning the template. |
| 857 * |
| 858 * @param {string} name The ID of the HTML element used as template. |
| 859 * @param {Function} opt_loadHtmlFn A function which, when called, will return |
| 860 * HTML that contains an element whose ID is 'name'. |
| 861 * |
| 862 * @return {Element|null} The DOM node of the template. (Only element nodes |
| 863 * can be found by ID, hence it's a Element.) |
| 864 */ |
| 865 function jstGetTemplate(name, opt_loadHtmlFn) { |
| 866 var doc = document; |
| 867 var section; |
| 868 if (opt_loadHtmlFn) { |
| 869 section = jstLoadTemplateIfNotPresent(doc, name, opt_loadHtmlFn); |
| 870 } else { |
| 871 section = domGetElementById(doc, name); |
| 872 } |
| 873 if (section) { |
| 874 JstProcessor.prepareTemplate_(section); |
| 875 var ret = domCloneElement(section); |
| 876 domRemoveAttribute(ret, STRING_id); |
| 877 return ret; |
| 878 } else { |
| 879 return null; |
| 880 } |
| 881 } |
| 882 |
| 883 /** |
| 884 * This function is the same as 'jstGetTemplate' but, if the template |
| 885 * does not exist, throw an exception. |
| 886 * |
| 887 * @param {string} name The ID of the HTML element used as template. |
| 888 * @param {Function} opt_loadHtmlFn A function which, when called, will return |
| 889 * HTML that contains an element whose ID is 'name'. |
| 890 * |
| 891 * @return {Element} The DOM node of the template. (Only element nodes |
| 892 * can be found by ID, hence it's a Element.) |
| 893 */ |
| 894 function jstGetTemplateOrDie(name, opt_loadHtmlFn) { |
| 895 var x = jstGetTemplate(name, opt_loadHtmlFn); |
| 896 check(x !== null); |
| 897 return /** @type Element */(x); |
| 898 } |
| 899 |
| 900 |
| 901 /** |
| 902 * If an element with id 'name' is not present in the document, call loadHtmlFn |
| 903 * and insert the result into the DOM. |
| 904 * |
| 905 * @param {Document} doc |
| 906 * @param {string} name |
| 907 * @param {Function} loadHtmlFn A function that returns HTML to be inserted |
| 908 * into the DOM. |
| 909 * @param {string} opt_target The id of a DOM object under which to attach the |
| 910 * HTML once it's inserted. An object with this id is created if it does not |
| 911 * exist. |
| 912 * @return {Element} The node whose id is 'name' |
| 913 */ |
| 914 function jstLoadTemplateIfNotPresent(doc, name, loadHtmlFn, opt_target) { |
| 915 var section = domGetElementById(doc, name); |
| 916 if (section) { |
| 917 return section; |
| 918 } |
| 919 // Load any necessary HTML and try again. |
| 920 jstLoadTemplate_(doc, loadHtmlFn(), opt_target || STRING_jsts); |
| 921 var section = domGetElementById(doc, name); |
| 922 if (!section) { |
| 923 log("Error: jstGetTemplate was provided with opt_loadHtmlFn, " + |
| 924 "but that function did not provide the id '" + name + "'."); |
| 925 } |
| 926 return /** @type Element */(section); |
| 927 } |
| 928 |
| 929 |
| 930 /** |
| 931 * Loads the given HTML text into the given document, so that |
| 932 * jstGetTemplate can find it. |
| 933 * |
| 934 * We append it to the element identified by targetId, which is hidden. |
| 935 * If it doesn't exist, it is created. |
| 936 * |
| 937 * @param {Document} doc The document to create the template in. |
| 938 * |
| 939 * @param {string} html HTML text to be inserted into the document. |
| 940 * |
| 941 * @param {string} targetId The id of a DOM object under which to attach the |
| 942 * HTML once it's inserted. An object with this id is created if it does not |
| 943 * exist. |
| 944 */ |
| 945 function jstLoadTemplate_(doc, html, targetId) { |
| 946 var existing_target = domGetElementById(doc, targetId); |
| 947 var target; |
| 948 if (!existing_target) { |
| 949 target = domCreateElement(doc, STRING_div); |
| 950 target.id = targetId; |
| 951 displayNone(target); |
| 952 positionAbsolute(target); |
| 953 domAppendChild(doc.body, target); |
| 954 } else { |
| 955 target = existing_target; |
| 956 } |
| 957 var div = domCreateElement(doc, STRING_div); |
| 958 target.appendChild(div); |
| 959 div.innerHTML = html; |
| 960 } |
| 961 |
| 962 |
| 963 /** |
| 964 * Sets the jsinstance attribute on a node according to its context. |
| 965 * |
| 966 * @param {Element} template The template DOM node to set the instance |
| 967 * attribute on. |
| 968 * |
| 969 * @param {Array} values The current input context, the array of |
| 970 * values of which the template node will render one instance. |
| 971 * |
| 972 * @param {number} index The index of this template node in values. |
| 973 */ |
| 974 function jstSetInstance(template, values, index) { |
| 975 if (index == jsLength(values) - 1) { |
| 976 domSetAttribute(template, ATT_instance, CHAR_asterisk + index); |
| 977 } else { |
| 978 domSetAttribute(template, ATT_instance, STRING_empty + index); |
| 979 } |
| 980 } |
| 981 |
| 982 |
| 983 /** |
| 984 * Log the current state. |
| 985 * @param {string} caller An identifier for the caller of .log_. |
| 986 * @param {Element} template The template node being processed. |
| 987 * @param {Object} jstAttributeValues The jst attributes of the template node. |
| 988 */ |
| 989 JstProcessor.prototype.logState_ = function( |
| 990 caller, template, jstAttributeValues) { |
| 991 if (MAPS_DEBUG) { |
| 992 var msg = '<table>'; |
| 993 msg += '<caption>' + caller + '</caption>'; |
| 994 msg += '<tbody>'; |
| 995 if (template.id) { |
| 996 msg += '<tr><td>' + 'id:' + '</td><td>' + template.id + '</td></tr>'; |
| 997 } |
| 998 if (template.name) { |
| 999 msg += '<tr><td>' + 'name:' + '</td><td>' + template.name + '</td></tr>'; |
| 1000 } |
| 1001 if (jstAttributeValues) { |
| 1002 msg += '<tr><td>' + 'attr:' + |
| 1003 '</td><td>' + jsToSource(jstAttributeValues) + '</td></tr>'; |
| 1004 } |
| 1005 msg += '</tbody></table><br/>'; |
| 1006 this.logs_.push(msg); |
| 1007 } |
| 1008 }; |
| 1009 |
| 1010 |
| 1011 /** |
| 1012 * Retrieve the processing logs. |
| 1013 * @return {Array.<string>} The processing logs. |
| 1014 */ |
| 1015 JstProcessor.prototype.getLogs = function() { |
| 1016 return this.logs_; |
| 1017 }; |
| 1018 |
OLD | NEW |