Move chrome\third_party\jstemplate to third_party\jstemplate since it's used from ui\.

chrome/third_party/jstemplate/jsevalcontext.js

-// 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 <mesch@google.com>
- *
- * @fileoverview This class is used to evaluate expressions in a local
- * context. Used by JstProcessor.
- */
-
-
-/**
- * Names of special variables defined by the jstemplate evaluation
- * context. These can be used in js expression in jstemplate
- * attributes.
- */
-var VAR_index = '$index';
-var VAR_count = '$count';
-var VAR_this = '$this';
-var VAR_context = '$context';
-var VAR_top = '$top';
-
-
-/**
- * The name of the global variable which holds the value to be returned if
- * context evaluation results in an error. 
- * Use JsEvalContext.setGlobal(GLOB_default, value) to set this.
- */
-var GLOB_default = '$default';
-
-
-/**
- * Un-inlined literals, to avoid object creation in IE6. TODO(mesch):
- * So far, these are only used here, but we could use them thoughout
- * the code and thus move them to constants.js.
- */
-var CHAR_colon = ':';
-var REGEXP_semicolon = /\s*;\s*/;
-
-
-/**
- * See constructor_()
- * @param {Object|null} opt_data
- * @param {Object} opt_parent
- * @constructor
- */
-function JsEvalContext(opt_data, opt_parent) {
-  this.constructor_.apply(this, arguments);
-}
-
-/**
- * Context for processing a jstemplate. The context contains a context
- * object, whose properties can be referred to in jstemplate
- * expressions, and it holds the locally defined variables.
- *
- * @param {Object|null} opt_data The context object. Null if no context.
- *
- * @param {Object} opt_parent The parent context, from which local
- * variables are inherited. Normally the context object of the parent
- * context is the object whose property the parent object is. Null for the
- * context of the root object.
- */
-JsEvalContext.prototype.constructor_ = function(opt_data, opt_parent) {
-  var me = this;
-
-  /**
-   * The context for variable definitions in which the jstemplate
-   * expressions are evaluated. Other than for the local context,
-   * which replaces the parent context, variable definitions of the
-   * parent are inherited. The special variable $this points to data_.
-   *
-   * If this instance is recycled from the cache, then the property is
-   * already initialized.
-   *
-   * @type {Object}
-   */
-  if (!me.vars_) {
-    me.vars_ = {};
-  }
-  if (opt_parent) {
-    // If there is a parent node, inherit local variables from the
-    // parent.
-    copyProperties(me.vars_, opt_parent.vars_);
-  } else {
-    // If a root node, inherit global symbols. Since every parent
-    // chain has a root with no parent, global variables will be
-    // present in the case above too. This means that globals can be
-    // overridden by locals, as it should be.
-    copyProperties(me.vars_, JsEvalContext.globals_);
-  }
-
-  /**
-   * The current context object is assigned to the special variable
-   * $this so it is possible to use it in expressions.
-   * @type Object
-   */
-  me.vars_[VAR_this] = opt_data;
-
-  /**
-   * The entire context structure is exposed as a variable so it can be
-   * passed to javascript invocations through jseval.
-   */
-  me.vars_[VAR_context] = me;
-
-  /**
-   * The local context of the input data in which the jstemplate
-   * expressions are evaluated. Notice that this is usually an Object,
-   * but it can also be a scalar value (and then still the expression
-   * $this can be used to refer to it). Notice this can even be value,
-   * undefined or null. Hence, we have to protect jsexec() from using
-   * undefined or null, yet we want $this to reflect the true value of
-   * the current context. Thus we assign the original value to $this,
-   * above, but for the expression context we replace null and
-   * undefined by the empty string.
-   *
-   * @type {Object|null}
-   */
-  me.data_ = getDefaultObject(opt_data, STRING_empty);
-
-  if (!opt_parent) {
-    // If this is a top-level context, create a variable reference to the data
-    // to allow for  accessing top-level properties of the original context
-    // data from child contexts.
-    me.vars_[VAR_top] = me.data_;
-  }
-};
-
-
-/**
- * A map of globally defined symbols. Every instance of JsExprContext
- * inherits them in its vars_.
- * @type Object
- */
-JsEvalContext.globals_ = {}
-
-
-/**
- * Sets a global symbol. It will be available like a variable in every
- * JsEvalContext instance. This is intended mainly to register
- * immutable global objects, such as functions, at load time, and not
- * to add global data at runtime. I.e. the same objections as to
- * global variables in general apply also here. (Hence the name
- * "global", and not "global var".)
- * @param {string} name
- * @param {Object|null} value
- */
-JsEvalContext.setGlobal = function(name, value) {
-  JsEvalContext.globals_[name] = value;
-};
-
-
-/**
- * Set the default value to be returned if context evaluation results in an 
- * error. (This can occur if a non-existent value was requested). 
- */
-JsEvalContext.setGlobal(GLOB_default, null);
-
-
-/**
- * A cache to reuse JsEvalContext instances. (IE6 perf)
- *
- * @type Array.<JsEvalContext>
- */
-JsEvalContext.recycledInstances_ = [];
-
-
-/**
- * A factory to create a JsEvalContext instance, possibly reusing
- * one from recycledInstances_. (IE6 perf)
- *
- * @param {Object} opt_data
- * @param {JsEvalContext} opt_parent
- * @return {JsEvalContext}
- */
-JsEvalContext.create = function(opt_data, opt_parent) {
-  if (jsLength(JsEvalContext.recycledInstances_) > 0) {
-    var instance = JsEvalContext.recycledInstances_.pop();
-    JsEvalContext.call(instance, opt_data, opt_parent);
-    return instance;
-  } else {
-    return new JsEvalContext(opt_data, opt_parent);
-  }
-};
-
-
-/**
- * Recycle a used JsEvalContext instance, so we can avoid creating one
- * the next time we need one. (IE6 perf)
- *
- * @param {JsEvalContext} instance
- */
-JsEvalContext.recycle = function(instance) {
-  for (var i in instance.vars_) {
-    // NOTE(mesch): We avoid object creation here. (IE6 perf)
-    delete instance.vars_[i];
-  }
-  instance.data_ = null;
-  JsEvalContext.recycledInstances_.push(instance);
-};
-
-
-/**
- * Executes a function created using jsEvalToFunction() in the context
- * of vars, data, and template.
- *
- * @param {Function} exprFunction A javascript function created from
- * a jstemplate attribute value.
- *
- * @param {Element} template DOM node of the template.
- *
- * @return {Object|null} The value of the expression from which
- * exprFunction was created in the current js expression context and
- * the context of template.
- */
-JsEvalContext.prototype.jsexec = function(exprFunction, template) {
-  try {
-    return exprFunction.call(template, this.vars_, this.data_);
-  } catch (e) {
-    log('jsexec EXCEPTION: ' + e + ' at ' + template +
-        ' with ' + exprFunction);
-    return JsEvalContext.globals_[GLOB_default];
-  }
-};
-
-
-/**
- * Clones the current context for a new context object. The cloned
- * context has the data object as its context object and the current
- * context as its parent context. It also sets the $index variable to
- * the given value. This value usually is the position of the data
- * object in a list for which a template is instantiated multiply.
- *
- * @param {Object} data The new context object.
- *
- * @param {number} index Position of the new context when multiply
- * instantiated. (See implementation of jstSelect().)
- * 
- * @param {number} count The total number of contexts that were multiply
- * instantiated. (See implementation of jstSelect().)
- *
- * @return {JsEvalContext}
- */
-JsEvalContext.prototype.clone = function(data, index, count) {
-  var ret = JsEvalContext.create(data, this);
-  ret.setVariable(VAR_index, index);
-  ret.setVariable(VAR_count, count);
-  return ret;
-};
-
-
-/**
- * Binds a local variable to the given value. If set from jstemplate
- * jsvalue expressions, variable names must start with $, but in the
- * API they only have to be valid javascript identifier.
- *
- * @param {string} name
- *
- * @param {Object?} value
- */
-JsEvalContext.prototype.setVariable = function(name, value) {
-  this.vars_[name] = value;
-};
-
-
-/**
- * Returns the value bound to the local variable of the given name, or
- * undefined if it wasn't set. There is no way to distinguish a
- * variable that wasn't set from a variable that was set to
- * undefined. Used mostly for testing.
- *
- * @param {string} name
- *
- * @return {Object?} value
- */
-JsEvalContext.prototype.getVariable = function(name) {
-  return this.vars_[name];
-};
-
-
-/**
- * Evaluates a string expression within the scope of this context
- * and returns the result.
- *
- * @param {string} expr A javascript expression
- * @param {Element} opt_template An optional node to serve as "this"
- *
- * @return {Object?} value
- */
-JsEvalContext.prototype.evalExpression = function(expr, opt_template) {
-  var exprFunction = jsEvalToFunction(expr);
-  return this.jsexec(exprFunction, opt_template);
-};
-
-
-/**
- * Uninlined string literals for jsEvalToFunction() (IE6 perf).
- */
-var STRING_a = 'a_';
-var STRING_b = 'b_';
-var STRING_with = 'with (a_) with (b_) return ';
-
-
-/**
- * Cache for jsEvalToFunction results.
- * @type Object
- */
-JsEvalContext.evalToFunctionCache_ = {};
-
-
-/**
- * Evaluates the given expression as the body of a function that takes
- * vars and data as arguments. Since the resulting function depends
- * only on expr, we cache the result so we save some Function
- * invocations, and some object creations in IE6.
- *
- * @param {string} expr A javascript expression.
- *
- * @return {Function} A function that returns the value of expr in the
- * context of vars and data.
- */
-function jsEvalToFunction(expr) {
-  if (!JsEvalContext.evalToFunctionCache_[expr]) {
-    try {
-      // NOTE(mesch): The Function constructor is faster than eval().
-      JsEvalContext.evalToFunctionCache_[expr] =
-        new Function(STRING_a, STRING_b, STRING_with + expr);
-    } catch (e) {
-      log('jsEvalToFunction (' + expr + ') EXCEPTION ' + e);
-    }
-  }
-  return JsEvalContext.evalToFunctionCache_[expr];
-}
-
-
-/**
- * Evaluates the given expression to itself. This is meant to pass
- * through string attribute values.
- *
- * @param {string} expr
- *
- * @return {string}
- */
-function jsEvalToSelf(expr) {
-  return expr;
-}
-
-
-/**
- * Parses the value of the jsvalues attribute in jstemplates: splits
- * it up into a map of labels and expressions, and creates functions
- * from the expressions that are suitable for execution by
- * JsEvalContext.jsexec(). All that is returned as a flattened array
- * of pairs of a String and a Function.
- *
- * @param {string} expr
- *
- * @return {Array}
- */
-function jsEvalToValues(expr) {
-  // TODO(mesch): It is insufficient to split the values by simply
-  // finding semi-colons, as the semi-colon may be part of a string
-  // constant or escaped.
-  var ret = [];
-  var values = expr.split(REGEXP_semicolon);
-  for (var i = 0, I = jsLength(values); i < I; ++i) {
-    var colon = values[i].indexOf(CHAR_colon);
-    if (colon < 0) {
-      continue;
-    }
-    var label = stringTrim(values[i].substr(0, colon));
-    var value = jsEvalToFunction(values[i].substr(colon + 1));
-    ret.push(label, value);
-  }
-  return ret;
-}
-
-
-/**
- * Parses the value of the jseval attribute of jstemplates: splits it
- * up into a list of expressions, and creates functions from the
- * expressions that are suitable for execution by
- * JsEvalContext.jsexec(). All that is returned as an Array of
- * Function.
- *
- * @param {string} expr
- *
- * @return {Array.<Function>}
- */
-function jsEvalToExpressions(expr) {
-  var ret = [];
-  var values = expr.split(REGEXP_semicolon);
-  for (var i = 0, I = jsLength(values); i < I; ++i) {
-    if (values[i]) {
-      var value = jsEvalToFunction(values[i]);
-      ret.push(value);
-    }
-  }
-  return ret;
-}