// Copyright 2006 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
/**
* Author: Steffen Meschkat <[email protected]>
*
* @fileoverview A simple formatter to project JavaScript data into
* HTML templates. The template is edited in place. I.e. in order to
* instantiate a template, clone it from the DOM first, and then
* process the cloned template. This allows for updating of templates:
* If the templates is processed again, changed values are merely
* updated.
*
* NOTE(mesch): IE DOM doesn't have importNode().
*
* NOTE(mesch): The property name "length" must not be used in input
* data, see comment in jstSelect_().
*/
/**
* Names of jstemplate attributes. These attributes are attached to
* normal HTML elements and bind expression context data to the HTML
* fragment that is used as template.
*/
var ATT_select = 'jsselect';
var ATT_instance = 'jsinstance';
var ATT_display = 'jsdisplay';
var ATT_values = 'jsvalues';
var ATT_vars = 'jsvars';
var ATT_eval = 'jseval';
var ATT_transclude = 'transclude';
var ATT_content = 'jscontent';
var ATT_skip = 'jsskip';
/**
* Name of the attribute that caches a reference to the parsed
* template processing attribute values on a template node.
*/
var ATT_jstcache = 'jstcache';
/**
* Name of the property that caches the parsed template processing
* attribute values on a template node.
*/
var PROP_jstcache = '__jstcache';
/**
* ID of the element that contains dynamically loaded jstemplates.
*/
var STRING_jsts = 'jsts';
/**
* Un-inlined string literals, to avoid object creation in
* IE6.
*/
var CHAR_asterisk = '*';
var CHAR_dollar = '$';
var CHAR_period = '.';
var CHAR_ampersand = '&';
var STRING_div = 'div';
var STRING_id = 'id';
var STRING_asteriskzero = '*0';
var STRING_zero = '0';
/**
* HTML template processor. Data values are bound to HTML templates
* using the attributes transclude, jsselect, jsdisplay, jscontent,
* jsvalues. The template is modifed in place. The values of those
* attributes are JavaScript expressions that are evaluated in the
* context of the data object fragment.
*
* @param {JsEvalContext} context Context created from the input data
* object.
*
* @param {Element} template DOM node of the template. This will be
* processed in place. After processing, it will still be a valid
* template that, if processed again with the same data, will remain
* unchanged.
*
* @param {boolean=} opt_debugging Optional flag to collect debugging
* information while processing the template. Only takes effect
* in MAPS_DEBUG.
*/
function jstProcess(context, template, opt_debugging) {
var processor = new JstProcessor;
JstProcessor.prepareTemplate_(template);
/**
* Caches the document of the template node, so we don't have to
* access it through ownerDocument.
* @type Document
*/
processor.document_ = ownerDocument(template);
processor.run_(bindFully(processor, processor.jstProcessOuter_,
context, template));
}
/**
* Internal class used by jstemplates to maintain context. This is
* necessary to process deep templates in Safari which has a
* relatively shallow maximum recursion depth of 100.
* @class
* @constructor
*/
function JstProcessor() {
}
/**
* Counter to generate node ids. These ids will be stored in
* ATT_jstcache and be used to lookup the preprocessed js attributes
* from the jstcache_. The id is stored in an attribute so it
* suvives cloneNode() and thus cloned template nodes can share the
* same cache entry.
* @type number
*/
JstProcessor.jstid_ = 0;
/**
* Map from jstid to processed js attributes.
* @type Object
*/
JstProcessor.jstcache_ = {};
/**
* The neutral cache entry. Used for all nodes that don't have any
* jst attributes. We still set the jsid attribute on those nodes so
* we can avoid to look again for all the other jst attributes that
* aren't there. Remember: not only the processing of the js
* attribute values is expensive and we thus want to cache it. The
* access to the attributes on the Node in the first place is
* expensive too.
*/
JstProcessor.jstcache_[0] = {};
/**
* Map from concatenated attribute string to jstid.
* The key is the concatenation of all jst atributes found on a node
* formatted as "name1=value1&name2=value2&...", in the order defined by
* JST_ATTRIBUTES. The value is the id of the jstcache_ entry that can
* be used for this node. This allows the reuse of cache entries in cases
* when a cached entry already exists for a given combination of attribute
* values. (For example when two different nodes in a template share the same
* JST attributes.)
* @type Object
*/
JstProcessor.jstcacheattributes_ = {};
/**
* Map for storing temporary attribute values in prepareNode_() so they don't
* have to be retrieved twice. (IE6 perf)
* @type Object
*/
JstProcessor.attributeValues_ = {};
/**
* A list for storing non-empty attributes found on a node in prepareNode_().
* The array is global since it can be reused - this way there is no need to
* construct a new array object for each invocation. (IE6 perf)
* @type Array
*/
JstProcessor.attributeList_ = [];
/**
* Prepares the template: preprocesses all jstemplate attributes.
*
* @param {Element} template
*/
JstProcessor.prepareTemplate_ = function(template) {
if (!template[PROP_jstcache]) {
domTraverseElements(template, function(node) {
JstProcessor.prepareNode_(node);
});
}
};
/**
* A list of attributes we use to specify jst processing instructions,
* and the functions used to parse their values.
*
* @type Array.<Array>
*/
var JST_ATTRIBUTES = [
[ ATT_select, jsEvalToFunction ],
[ ATT_display, jsEvalToFunction ],
[ ATT_values, jsEvalToValues ],
[ ATT_vars, jsEvalToValues ],
[ ATT_eval, jsEvalToExpressions ],
[ ATT_transclude, jsEvalToSelf ],
[ ATT_content, jsEvalToFunction ],
[ ATT_skip, jsEvalToFunction ]
];
/**
* Prepares a single node: preprocesses all template attributes of the
* node, and if there are any, assigns a jsid attribute and stores the
* preprocessed attributes under the jsid in the jstcache.
*
* @param {Element} node
*
* @return {Object} The jstcache entry. The processed jst attributes
* are properties of this object. If the node has no jst attributes,
* returns an object with no properties (the jscache_[0] entry).
*/
JstProcessor.prepareNode_ = function(node) {
// If the node already has a cache property, return it.
if (node[PROP_jstcache]) {
return node[PROP_jstcache];
}
// If it is not found, we always set the PROP_jstcache property on the node.
// Accessing the property is faster than executing getAttribute(). If we
// don't find the property on a node that was cloned in jstSelect_(), we
// will fall back to check for the attribute and set the property
// from cache.
// If the node has an attribute indexing a cache object, set it as a property
// and return it.
var jstid = domGetAttribute(node, ATT_jstcache);
if (jstid != null) {
return node[PROP_jstcache] = JstProcessor.jstcache_[jstid];
}
var attributeValues = JstProcessor.attributeValues_;
var attributeList = JstProcessor.attributeList_;
attributeList.length = 0;
// Look for interesting attributes.
for (var i = 0, I = jsLength(JST_ATTRIBUTES); i < I; ++i) {
var name = JST_ATTRIBUTES[i][0];
var value = domGetAttribute(node, name);
attributeValues[name] = value;
if (value != null) {
attributeList.push(name + "=" + value);
}
}
// If none found, mark this node to prevent further inspection, and return
// an empty cache object.
if (attributeList.length == 0) {
domSetAttribute(node, ATT_jstcache, STRING_zero);
return node[PROP_jstcache] = JstProcessor.jstcache_[0];
}
// If we already have a cache object corresponding to these attributes,
// annotate the node with it, and return it.
var attstring = attributeList.join(CHAR_ampersand);
if (jstid = JstProcessor.jstcacheattributes_[attstring]) {
domSetAttribute(node, ATT_jstcache, jstid);
return node[PROP_jstcache] = JstProcessor.jstcache_[jstid];
}
// Otherwise, build a new cache object.
var jstcache = {};
for (var i = 0, I = jsLength(JST_ATTRIBUTES); i < I; ++i) {
var att = JST_ATTRIBUTES[i];
var name = att[0];
var parse = att[1];
var value = attributeValues[name];
if (value != null) {
jstcache[name] = parse(value);
}
}
jstid = STRING_empty + ++JstProcessor.jstid_;
domSetAttribute(node, ATT_jstcache, jstid);
JstProcessor.jstcache_[jstid] = jstcache;
JstProcessor.jstcacheattributes_[attstring] = jstid;
return node[PROP_jstcache] = jstcache;
};
/**
* Runs the given function in our state machine.
*
* It's informative to view the set of all function calls as a tree:
* - nodes are states
* - edges are state transitions, implemented as calls to the pending
* functions in the stack.
* - pre-order function calls are downward edges (recursion into call).
* - post-order function calls are upward edges (return from call).
* - leaves are nodes which do not recurse.
* We represent the call tree as an array of array of calls, indexed as
* stack[depth][index]. Here [depth] indexes into the call stack, and
* [index] indexes into the call queue at that depth. We require a call
* queue so that a node may branch to more than one child
* (which will be called serially), typically due to a loop structure.
*
* @param {Function} f The first function to run.
*/
JstProcessor.prototype.run_ = function(f) {
var me = this;
/**
* A stack of queues of pre-order calls.
* The inner arrays (constituent queues) are structured as
* [ arg2, arg1, method, arg2, arg1, method, ...]
* ie. a flattened array of methods with 2 arguments, in reverse order
* for efficient push/pop.
*
* The outer array is a stack of such queues.
*
* @type Array.<Array>
*/
var calls = me.calls_ = [];
/**
* The index into the queue for each depth. NOTE: Alternative would
* be to maintain the queues in reverse order (popping off of the
* end) but the repeated calls to .pop() consumed 90% of this
* function's execution time.
* @type Array.<number>
*/
var queueIndices = me.queueIndices_ = [];
/**
* A pool of empty arrays. Minimizes object allocation for IE6's benefit.
* @type Array.<Array>
*/
var arrayPool = me.arrayPool_ = [];
f();
var queue, queueIndex;
var method, arg1, arg2;
var temp;
while (calls.length) {
queue = calls[calls.length - 1];
queueIndex = queueIndices[queueIndices.length - 1];
if (queueIndex >= queue.length) {
me.recycleArray_(calls.pop());
queueIndices.pop();
continue;
}
// Run the first function in the queue.
method = queue[queueIndex++];
arg1 = queue[queueIndex++];
arg2 = queue[queueIndex++];
queueIndices[queueIndices.length - 1] = queueIndex;
method.call(me, arg1, arg2);
}
};
/**
* Pushes one or more functions onto the stack. These will be run in sequence,
* interspersed with any recursive calls that they make.
*
* This method takes ownership of the given array!
*
* @param {Array} args Array of method calls structured as
* [ method, arg1, arg2, method, arg1, arg2, ... ]
*/
JstProcessor.prototype.push_ = function(args) {
this.calls_.push(args);
this.queueIndices_.push(0);
};
/**
* Enable/disable debugging.
* @param {boolean} debugging New state
*/
JstProcessor.prototype.setDebugging = function(debugging) {
};
JstProcessor.prototype.createArray_ = function() {
if (this.arrayPool_.length) {
return this.arrayPool_.pop();
} else {
return [];
}
};
JstProcessor.prototype.recycleArray_ = function(array) {
arrayClear(array);
this.arrayPool_.push(array);
};
/**
* Implements internals of jstProcess. This processes the two
* attributes transclude and jsselect, which replace or multiply
* elements, hence the name "outer". The remainder of the attributes
* is processed in jstProcessInner_(), below. That function
* jsProcessInner_() only processes attributes that affect an existing
* node, but doesn't create or destroy nodes, hence the name
* "inner". jstProcessInner_() is called through jstSelect_() if there
* is a jsselect attribute (possibly for newly created clones of the
* current template node), or directly from here if there is none.
*
* @param {JsEvalContext} context
*
* @param {Element} template
*/
JstProcessor.prototype.jstProcessOuter_ = function(context, template) {
var me = this;
var jstAttributes = me.jstAttributes_(template);
var transclude = jstAttributes[ATT_transclude];
if (transclude) {
var tr = jstGetTemplate(transclude);
if (tr) {
domReplaceChild(tr, template);
var call = me.createArray_();
call.push(me.jstProcessOuter_, context, tr);
me.push_(call);
} else {
domRemoveNode(template);
}
return;
}
var select = jstAttributes[ATT_select];
if (select) {
me.jstSelect_(context, template, select);
} else {
me.jstProcessInner_(context, template);
}
};
/**
* Implements internals of jstProcess. This processes all attributes
* except transclude and jsselect. It is called either from
* jstSelect_() for nodes that have a jsselect attribute so that the
* jsselect attribute will not be processed again, or else directly
* from jstProcessOuter_(). See the comment on jstProcessOuter_() for
* an explanation of the name.
*
* @param {JsEvalContext} context
*
* @param {Element} template
*/
JstProcessor.prototype.jstProcessInner_ = function(context, template) {
var me = this;
var jstAttributes = me.jstAttributes_(template);
// NOTE(mesch): See NOTE on ATT_content why this is a separate
// attribute, and not a special value in ATT_values.
var display = jstAttributes[ATT_display];
if (display) {
var shouldDisplay = context.jsexec(display, template);
if (!shouldDisplay) {
displayNone(template);
return;
}
displayDefault(template);
}
// NOTE(mesch): jsvars is evaluated before jsvalues, because it's
// more useful to be able to use var values in attribute value
// expressions than vice versa.
var values = jstAttributes[ATT_vars];
if (values) {
me.jstVars_(context, template, values);
}
values = jstAttributes[ATT_values];
if (values) {
me.jstValues_(context, template, values);
}
// Evaluate expressions immediately. Useful for hooking callbacks
// into jstemplates.
//
// NOTE(mesch): Evaluation order is sometimes significant, e.g. when
// the expression evaluated in jseval relies on the values set in
// jsvalues, so it needs to be evaluated *after*
// jsvalues. TODO(mesch): This is quite arbitrary, it would be
// better if this would have more necessity to it.
var expressions = jstAttributes[ATT_eval];
if (expressions) {
for (var i = 0, I = jsLength(expressions); i < I; ++i) {
context.jsexec(expressions[i], template);
}
}
var skip = jstAttributes[ATT_skip];
if (skip) {
var shouldSkip = context.jsexec(skip, template);
if (shouldSkip) return;
}
// NOTE(mesch): content is a separate attribute, instead of just a
// special value mentioned in values, for two reasons: (1) it is
// fairly common to have only mapped content, and writing
// content="expr" is shorter than writing values="content:expr", and
// (2) the presence of content actually terminates traversal, and we
// need to check for that. Display is a separate attribute for a
// reason similar to the second, in that its presence *may*
// terminate traversal.
var content = jstAttributes[ATT_content];
if (content) {
me.jstContent_(context, template, content);
} else {
// Newly generated children should be ignored, so we explicitly
// store the children to be processed.
var queue = me.createArray_();
for (var c = template.firstChild; c; c = c.nextSibling) {
if (c.nodeType == DOM_ELEMENT_NODE) {
queue.push(me.jstProcessOuter_, context, c);
}
}
if (queue.length) me.push_(queue);
}
};
/**
* Implements the jsselect attribute: evalutes the value of the
* jsselect attribute in the current context, with the current
* variable bindings (see JsEvalContext.jseval()). If the value is an
* array, the current template node is multiplied once for every
* element in the array, with the array element being the context
* object. If the array is empty, or the value is undefined, then the
* current template node is dropped. If the value is not an array,
* then it is just made the context object.
*
* @param {JsEvalContext} context The current evaluation context.
*
* @param {Element} template The currently processed node of the template.
*
* @param {Function} select The javascript expression to evaluate.
*/
JstProcessor.prototype.jstSelect_ = function(context, template, select) {
var me = this;
var value = context.jsexec(select, template);
// Enable reprocessing: if this template is reprocessed, then only
// fill the section instance here. Otherwise do the cardinal
// processing of a new template.
var instance = domGetAttribute(template, ATT_instance);
var instanceLast = false;
if (instance) {
if (instance.charAt(0) == CHAR_asterisk) {
instance = parseInt10(instance.substr(1));
instanceLast = true;
} else {
instance = parseInt10(/** @type string */(instance));
}
}
// The expression value instanceof Array is occasionally false for
// arrays, seen in Firefox. Thus we recognize an array as an object
// which is not null that has a length property. Notice that this
// also matches input data with a length property, so this property
// name should be avoided in input data.
var multiple = isArray(value);
var count = multiple ? jsLength(value) : 1;
var multipleEmpty = (multiple && count == 0);
if (multiple) {
value = /** @type Array */(value);
if (multipleEmpty) {
// For an empty array, keep the first template instance and mark
// it last. Remove all other template instances.
if (!instance) {
domSetAttribute(template, ATT_instance, STRING_asteriskzero);
displayNone(template);
} else {
domRemoveNode(template);
}
} else {
displayDefault(template);
// For a non empty array, create as many template instances as
// are needed. If the template is first processed, as many
// template instances are needed as there are values in the
// array. If the template is reprocessed, new template instances
// are only needed if there are more array values than template
// instances. Those additional instances are created by
// replicating the last template instance.
//
// When the template is first processed, there is no jsinstance
// attribute. This is indicated by instance === null, except in
// opera it is instance === "". Notice also that the === is
// essential, because 0 == "", presumably via type coercion to
// boolean.
if (instance === null || instance === STRING_empty ||
(instanceLast && instance < count - 1)) {
// A queue of calls to push.
var queue = me.createArray_();
var instancesStart = /** @type {number} */(instance || 0);
var i, I, clone;
for (i = instancesStart, I = count - 1; i < I; ++i) {
var node = domCloneNode(template);
domInsertBefore(node, template);
jstSetInstance(/** @type Element */(node), value, i);
clone = context.clone(value[i], i, count);
queue.push(me.jstProcessInner_, clone, node,
JsEvalContext.recycle, clone, null);
}
// Push the originally present template instance last to keep
// the order aligned with the DOM order, because the newly
// created template instances are inserted *before* the
// original instance.
jstSetInstance(template, value, i);
clone = context.clone(value[i], i, count);
queue.push(me.jstProcessInner_, clone, template,
JsEvalContext.recycle, clone, null);
me.push_(queue);
} else if (instance < count) {
var v = value[/** @type {number} */(instance)];
jstSetInstance(template, value, instance);
var clone = context.clone(v, instance, count);
var queue = me.createArray_();
queue.push(me.jstProcessInner_, clone, template,
JsEvalContext.recycle, clone, null);
me.push_(queue);
} else {
domRemoveNode(template);
}
}
} else {
if (value == null) {
displayNone(template);
} else {
displayDefault(template);
var clone = context.clone(value, 0, 1);
var queue = me.createArray_();
queue.push(me.jstProcessInner_, clone, template,
JsEvalContext.recycle, clone, null);
me.push_(queue);
}
}
};
/**
* Implements the jsvars attribute: evaluates each of the values and
* assigns them to variables in the current context. Similar to
* jsvalues, except that all values are treated as vars, independent
* of their names.
*
* @param {JsEvalContext} context Current evaluation context.
*
* @param {Element} template Currently processed template node.
*
* @param {Array} values Processed value of the jsvalues attribute: a
* flattened array of pairs. The second element in the pair is a
* function that can be passed to jsexec() for evaluation in the
* current jscontext, and the first element is the variable name that
* the value returned by jsexec is assigned to.
*/
JstProcessor.prototype.jstVars_ = function(context, template, values) {
for (var i = 0, I = jsLength(values); i < I; i += 2) {
var label = values[i];
var value = context.jsexec(values[i+1], template);
context.setVariable(label, value);
}
};
/**
* Implements the jsvalues attribute: evaluates each of the values and
* assigns them to variables in the current context (if the name
* starts with '$', javascript properties of the current template node
* (if the name starts with '.'), or DOM attributes of the current
* template node (otherwise). Since DOM attribute values are always
* strings, the value is coerced to string in the latter case,
* otherwise it's the uncoerced javascript value.
*
* @param {JsEvalContext} context Current evaluation context.
*
* @param {Element} template Currently processed template node.
*
* @param {Array} values Processed value of the jsvalues attribute: a
* flattened array of pairs. The second element in the pair is a
* function that can be passed to jsexec() for evaluation in the
* current jscontext, and the first element is the label that
* determines where the value returned by jsexec is assigned to.
*/
JstProcessor.prototype.jstValues_ = function(context, template, values) {
for (var i = 0, I = jsLength(values); i < I; i += 2) {
var label = values[i];
var value = context.jsexec(values[i+1], template);
if (label.charAt(0) == CHAR_dollar) {
// A jsvalues entry whose name starts with $ sets a local
// variable.
context.setVariable(label, value);
} else if (label.charAt(0) == CHAR_period) {
// A jsvalues entry whose name starts with . sets a property of
// the current template node. The name may have further dot
// separated components, which are translated into namespace
// objects. This specifically allows to set properties on .style
// using jsvalues. NOTE(mesch): Setting the style attribute has
// no effect in IE and hence should not be done anyway.
var nameSpaceLabel = label.substr(1).split(CHAR_period);
var nameSpaceObject = template;
var nameSpaceDepth = jsLength(nameSpaceLabel);
for (var j = 0, J = nameSpaceDepth - 1; j < J; ++j) {
var jLabel = nameSpaceLabel[j];
if (!nameSpaceObject[jLabel]) {
nameSpaceObject[jLabel] = {};
}
nameSpaceObject = nameSpaceObject[jLabel];
}
nameSpaceObject[nameSpaceLabel[nameSpaceDepth - 1]] = value;
} else if (label) {
// Any other jsvalues entry sets an attribute of the current
// template node.
if (typeof value == TYPE_boolean) {
// Handle boolean values that are set as attributes specially,
// according to the XML/HTML convention.
if (value) {
domSetAttribute(template, label, label);
} else {
domRemoveAttribute(template, label);
}
} else {
domSetAttribute(template, label, STRING_empty + value);
}
}
}
};
/**
* Implements the jscontent attribute. Evalutes the expression in
* jscontent in the current context and with the current variables,
* and assigns its string value to the content of the current template
* node.
*
* @param {JsEvalContext} context Current evaluation context.
*
* @param {Element} template Currently processed template node.
*
* @param {Function} content Processed value of the jscontent
* attribute.
*/
JstProcessor.prototype.jstContent_ = function(context, template, content) {
// NOTE(mesch): Profiling shows that this method costs significant
// time. In jstemplate_perf.html, it's about 50%. I tried to replace
// by HTML escaping and assignment to innerHTML, but that was even
// slower.
var value = STRING_empty + context.jsexec(content, template);
// Prevent flicker when refreshing a template and the value doesn't
// change.
if (template.innerHTML == value) {
return;
}
while (template.firstChild) {
domRemoveNode(template.firstChild);
}
var t = domCreateTextNode(this.document_, value);
domAppendChild(template, t);
};
/**
* Caches access to and parsing of template processing attributes. If
* domGetAttribute() is called every time a template attribute value
* is used, it takes more than 10% of the time.
*
* @param {Element} template A DOM element node of the template.
*
* @return {Object} A javascript object that has all js template
* processing attribute values of the node as properties.
*/
JstProcessor.prototype.jstAttributes_ = function(template) {
if (template[PROP_jstcache]) {
return template[PROP_jstcache];
}
var jstid = domGetAttribute(template, ATT_jstcache);
if (jstid) {
return template[PROP_jstcache] = JstProcessor.jstcache_[jstid];
}
return JstProcessor.prepareNode_(template);
};
/**
* Helps to implement the transclude attribute, and is the initial
* call to get hold of a template from its ID.
*
* If the ID is not present in the DOM, and opt_loadHtmlFn is specified, this
* function will call that function and add the result to the DOM, before
* returning the template.
*
* @param {string} name The ID of the HTML element used as template.
* @param {Function=} opt_loadHtmlFn A function which, when called, will return
* HTML that contains an element whose ID is 'name'.
*
* @return {Element|null} The DOM node of the template. (Only element nodes
* can be found by ID, hence it's a Element.)
*/
function jstGetTemplate(name, opt_loadHtmlFn) {
var doc = document;
var section;
if (opt_loadHtmlFn) {
section = jstLoadTemplateIfNotPresent(doc, name, opt_loadHtmlFn);
} else {
section = domGetElementById(doc, name);
}
if (section) {
JstProcessor.prepareTemplate_(section);
var ret = domCloneElement(section);
domRemoveAttribute(ret, STRING_id);
return ret;
} else {
return null;
}
}
/**
* This function is the same as 'jstGetTemplate' but, if the template
* does not exist, throw an exception.
*
* @param {string} name The ID of the HTML element used as template.
* @param {Function} opt_loadHtmlFn A function which, when called, will return
* HTML that contains an element whose ID is 'name'.
*
* @return {Element} The DOM node of the template. (Only element nodes
* can be found by ID, hence it's a Element.)
*/
function jstGetTemplateOrDie(name, opt_loadHtmlFn) {
var x = jstGetTemplate(name, opt_loadHtmlFn);
if (x === null) {
throw new Error('jstGetTemplate() returned null');
}
return /** @type {Element} */(x);
}
/**
* If an element with id 'name' is not present in the document, call loadHtmlFn
* and insert the result into the DOM.
*
* @param {Document} doc
* @param {string} name
* @param {Function} loadHtmlFn A function that returns HTML to be inserted
* into the DOM.
* @param {string=} opt_target The id of a DOM object under which to attach the
* HTML once it's inserted. An object with this id is created if it does not
* exist.
* @return {Element} The node whose id is 'name'
*/
function jstLoadTemplateIfNotPresent(doc, name, loadHtmlFn, opt_target) {
var section = domGetElementById(doc, name);
if (section) {
return section;
}
// Load any necessary HTML and try again.
jstLoadTemplate_(doc, loadHtmlFn(), opt_target || STRING_jsts);
var section = domGetElementById(doc, name);
if (!section) {
log("Error: jstGetTemplate was provided with opt_loadHtmlFn, " +
"but that function did not provide the id '" + name + "'.");
}
return /** @type Element */(section);
}
/**
* Loads the given HTML text into the given document, so that
* jstGetTemplate can find it.
*
* We append it to the element identified by targetId, which is hidden.
* If it doesn't exist, it is created.
*
* @param {Document} doc The document to create the template in.
*
* @param {string} html HTML text to be inserted into the document.
*
* @param {string} targetId The id of a DOM object under which to attach the
* HTML once it's inserted. An object with this id is created if it does not
* exist.
*/
function jstLoadTemplate_(doc, html, targetId) {
var existing_target = domGetElementById(doc, targetId);
var target;
if (!existing_target) {
target = domCreateElement(doc, STRING_div);
target.id = targetId;
displayNone(target);
positionAbsolute(target);
domAppendChild(doc.body, target);
} else {
target = existing_target;
}
var div = domCreateElement(doc, STRING_div);
target.appendChild(div);
div.innerHTML = html;
}
/**
* Sets the jsinstance attribute on a node according to its context.
*
* @param {Element} template The template DOM node to set the instance
* attribute on.
*
* @param {Array} values The current input context, the array of
* values of which the template node will render one instance.
*
* @param {number|string} index The index of this template node in values.
*/
function jstSetInstance(template, values, index) {
if (index == jsLength(values) - 1) {
domSetAttribute(template, ATT_instance, CHAR_asterisk + index);
} else {
domSetAttribute(template, ATT_instance, STRING_empty + index);
}
}
/**
* Log the current state.
* @param {string} caller An identifier for the caller of .log_.
* @param {Element} template The template node being processed.
* @param {Object} jstAttributeValues The jst attributes of the template node.
*/
JstProcessor.prototype.logState_ = function(
caller, template, jstAttributeValues) {
};
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