text: // Copyright 2006-2008 the V8 project authors. All rights reserved.
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  //     * Redistributions of source code must retain the above copyright
  //       notice, this list of conditions and the following disclaimer.
  //     * Redistributions in binary form must reproduce the above
  //       copyright notice, this list of conditions and the following
  //       disclaimer in the documentation and/or other materials provided
  //       with the distribution.
  //     * Neither the name of Google Inc. nor the names of its
  //       contributors may be used to endorse or promote products derived
  //       from this software without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  // Handle id counters.
  var next_handle_ = 0;
  var next_transient_handle_ = -1;
  
  // Mirror cache.
  var mirror_cache_ = [];
  
  
  /**
   * Clear the mirror handle cache.
   */
  function ClearMirrorCache() {
    next_handle_ = 0;
    mirror_cache_ = [];
  }
  
  
  /**
   * Returns the mirror for a specified value or object.
   *
   * @param {value or Object} value the value or object to retreive the mirror for
   * @param {boolean} transient indicate whether this object is transient and
   *    should not be added to the mirror cache. The default is not transient.
   * @returns {Mirror} the mirror reflects the passed value or object
   */
  function MakeMirror(value, opt_transient) {
    var mirror;
  
    // Look for non transient mirrors in the mirror cache.
    if (!opt_transient) {
      for (id in mirror_cache_) {
        mirror = mirror_cache_[id];
        if (mirror.value() === value) {
          return mirror;
        }
        // Special check for NaN as NaN == NaN is false.
        if (mirror.isNumber() && isNaN(mirror.value()) &&
            typeof value == 'number' && isNaN(value)) {
          return mirror;
        }
      }
    }
  
    if (IS_UNDEFINED(value)) {
      mirror = new UndefinedMirror();
    } else if (IS_NULL(value)) {
      mirror = new NullMirror();
    } else if (IS_BOOLEAN(value)) {
      mirror = new BooleanMirror(value);
    } else if (IS_NUMBER(value)) {
      mirror = new NumberMirror(value);
    } else if (IS_STRING(value)) {
      mirror = new StringMirror(value);
    } else if (IS_ARRAY(value)) {
      mirror = new ArrayMirror(value);
    } else if (IS_DATE(value)) {
      mirror = new DateMirror(value);
    } else if (IS_FUNCTION(value)) {
      mirror = new FunctionMirror(value);
    } else if (IS_REGEXP(value)) {
      mirror = new RegExpMirror(value);
    } else if (IS_ERROR(value)) {
      mirror = new ErrorMirror(value);
    } else if (IS_SCRIPT(value)) {
      mirror = new ScriptMirror(value);
    } else {
      mirror = new ObjectMirror(value, OBJECT_TYPE, opt_transient);
    }
  
    mirror_cache_[mirror.handle()] = mirror;
    return mirror;
  }
  
  
  /**
   * Returns the mirror for a specified mirror handle.
   *
   * @param {number} handle the handle to find the mirror for
   * @returns {Mirror or undefiend} the mirror with the requested handle or
   *     undefined if no mirror with the requested handle was found
   */
  function LookupMirror(handle) {
    return mirror_cache_[handle];
  }
  
  
  /**
   * Returns the mirror for the undefined value.
   *
   * @returns {Mirror} the mirror reflects the undefined value
   */
  function GetUndefinedMirror() {
    return MakeMirror(void 0);
  }
  
  
  /**
   * Inherit the prototype methods from one constructor into another.
   *
   * The Function.prototype.inherits from lang.js rewritten as a standalone
   * function (not on Function.prototype). NOTE: If this file is to be loaded
   * during bootstrapping this function needs to be revritten using some native
   * functions as prototype setup using normal JavaScript does not work as
   * expected during bootstrapping (see mirror.js in r114903).
   *
   * @param {function} ctor Constructor function which needs to inherit the
   *     prototype
   * @param {function} superCtor Constructor function to inherit prototype from
   */
  function inherits(ctor, superCtor) {
    var tempCtor = function(){};
    tempCtor.prototype = superCtor.prototype;
    ctor.super_ = superCtor.prototype;
    ctor.prototype = new tempCtor();
    ctor.prototype.constructor = ctor;
  }
  
  
  // Type names of the different mirrors.
  var UNDEFINED_TYPE = 'undefined';
  var NULL_TYPE = 'null';
  var BOOLEAN_TYPE = 'boolean';
  var NUMBER_TYPE = 'number';
  var STRING_TYPE = 'string';
  var OBJECT_TYPE = 'object';
  var FUNCTION_TYPE = 'function';
  var REGEXP_TYPE = 'regexp';
  var ERROR_TYPE = 'error';
  var PROPERTY_TYPE = 'property';
  var FRAME_TYPE = 'frame';
  var SCRIPT_TYPE = 'script';
  var CONTEXT_TYPE = 'context';
  var SCOPE_TYPE = 'scope';
  
  // Maximum length when sending strings through the JSON protocol.
  var kMaxProtocolStringLength = 80;
  
  // Different kind of properties.
  var PropertyKind = {};
  PropertyKind.Named   = 1;
  PropertyKind.Indexed = 2;
  
  
  // A copy of the PropertyType enum from global.h
  var PropertyType = {};
  PropertyType.Normal                  = 0;
  PropertyType.Field                   = 1;
  PropertyType.ConstantFunction        = 2;
  PropertyType.Callbacks               = 3;
  PropertyType.Handler                 = 4;
  PropertyType.Interceptor             = 5;
  PropertyType.MapTransition           = 6;
  PropertyType.ExternalArrayTransition = 7;
  PropertyType.ConstantTransition      = 8;
  PropertyType.NullDescriptor          = 9;
  
  
  // Different attributes for a property.
  var PropertyAttribute = {};
  PropertyAttribute.None       = NONE;
  PropertyAttribute.ReadOnly   = READ_ONLY;
  PropertyAttribute.DontEnum   = DONT_ENUM;
  PropertyAttribute.DontDelete = DONT_DELETE;
  
  
  // A copy of the scope types from runtime.cc.
  var ScopeType = { Global: 0,
                    Local: 1,
                    With: 2,
                    Closure: 3,
                    Catch: 4,
                    Block: 5 };
  
  
  // Mirror hierarchy:
  //   - Mirror
  //     - ValueMirror
  //       - UndefinedMirror
  //       - NullMirror
  //       - NumberMirror
  //       - StringMirror
  //       - ObjectMirror
  //         - FunctionMirror
  //           - UnresolvedFunctionMirror
  //         - ArrayMirror
  //         - DateMirror
  //         - RegExpMirror
  //         - ErrorMirror
  //     - PropertyMirror
  //     - FrameMirror
  //     - ScriptMirror
  
  
  /**
   * Base class for all mirror objects.
   * @param {string} type The type of the mirror
   * @constructor
   */
  function Mirror(type) {
    this.type_ = type;
  }
  
  
  Mirror.prototype.type = function() {
    return this.type_;
  };
  
  
  /**
   * Check whether the mirror reflects a value.
   * @returns {boolean} True if the mirror reflects a value.
   */
  Mirror.prototype.isValue = function() {
    return this instanceof ValueMirror;
  };
  
  
  /**
   * Check whether the mirror reflects the undefined value.
   * @returns {boolean} True if the mirror reflects the undefined value.
   */
  Mirror.prototype.isUndefined = function() {
    return this instanceof UndefinedMirror;
  };
  
  
  /**
   * Check whether the mirror reflects the null value.
   * @returns {boolean} True if the mirror reflects the null value
   */
  Mirror.prototype.isNull = function() {
    return this instanceof NullMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a boolean value.
   * @returns {boolean} True if the mirror reflects a boolean value
   */
  Mirror.prototype.isBoolean = function() {
    return this instanceof BooleanMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a number value.
   * @returns {boolean} True if the mirror reflects a number value
   */
  Mirror.prototype.isNumber = function() {
    return this instanceof NumberMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a string value.
   * @returns {boolean} True if the mirror reflects a string value
   */
  Mirror.prototype.isString = function() {
    return this instanceof StringMirror;
  };
  
  
  /**
   * Check whether the mirror reflects an object.
   * @returns {boolean} True if the mirror reflects an object
   */
  Mirror.prototype.isObject = function() {
    return this instanceof ObjectMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a function.
   * @returns {boolean} True if the mirror reflects a function
   */
  Mirror.prototype.isFunction = function() {
    return this instanceof FunctionMirror;
  };
  
  
  /**
   * Check whether the mirror reflects an unresolved function.
   * @returns {boolean} True if the mirror reflects an unresolved function
   */
  Mirror.prototype.isUnresolvedFunction = function() {
    return this instanceof UnresolvedFunctionMirror;
  };
  
  
  /**
   * Check whether the mirror reflects an array.
   * @returns {boolean} True if the mirror reflects an array
   */
  Mirror.prototype.isArray = function() {
    return this instanceof ArrayMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a date.
   * @returns {boolean} True if the mirror reflects a date
   */
  Mirror.prototype.isDate = function() {
    return this instanceof DateMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a regular expression.
   * @returns {boolean} True if the mirror reflects a regular expression
   */
  Mirror.prototype.isRegExp = function() {
    return this instanceof RegExpMirror;
  };
  
  
  /**
   * Check whether the mirror reflects an error.
   * @returns {boolean} True if the mirror reflects an error
   */
  Mirror.prototype.isError = function() {
    return this instanceof ErrorMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a property.
   * @returns {boolean} True if the mirror reflects a property
   */
  Mirror.prototype.isProperty = function() {
    return this instanceof PropertyMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a stack frame.
   * @returns {boolean} True if the mirror reflects a stack frame
   */
  Mirror.prototype.isFrame = function() {
    return this instanceof FrameMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a script.
   * @returns {boolean} True if the mirror reflects a script
   */
  Mirror.prototype.isScript = function() {
    return this instanceof ScriptMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a context.
   * @returns {boolean} True if the mirror reflects a context
   */
  Mirror.prototype.isContext = function() {
    return this instanceof ContextMirror;
  };
  
  
  /**
   * Check whether the mirror reflects a scope.
   * @returns {boolean} True if the mirror reflects a scope
   */
  Mirror.prototype.isScope = function() {
    return this instanceof ScopeMirror;
  };
  
  
  /**
   * Allocate a handle id for this object.
   */
  Mirror.prototype.allocateHandle_ = function() {
    this.handle_ = next_handle_++;
  };
  
  
  /**
   * Allocate a transient handle id for this object. Transient handles are
   * negative.
   */
  Mirror.prototype.allocateTransientHandle_ = function() {
    this.handle_ = next_transient_handle_--;
  };
  
  
  Mirror.prototype.toText = function() {
    // Simpel to text which is used when on specialization in subclass.
    return "#<" + this.constructor.name + ">";
  };
  
  
  /**
   * Base class for all value mirror objects.
   * @param {string} type The type of the mirror
   * @param {value} value The value reflected by this mirror
   * @param {boolean} transient indicate whether this object is transient with a
   *    transient handle
   * @constructor
   * @extends Mirror
   */
  function ValueMirror(type, value, transient) {
    %_CallFunction(this, type, Mirror);
    this.value_ = value;
    if (!transient) {
      this.allocateHandle_();
    } else {
      this.allocateTransientHandle_();
    }
  }
  inherits(ValueMirror, Mirror);
  
  
  Mirror.prototype.handle = function() {
    return this.handle_;
  };
  
  
  /**
   * Check whether this is a primitive value.
   * @return {boolean} True if the mirror reflects a primitive value
   */
  ValueMirror.prototype.isPrimitive = function() {
    var type = this.type();
    return type === 'undefined' ||
           type === 'null' ||
           type === 'boolean' ||
           type === 'number' ||
           type === 'string';
  };
  
  
  /**
   * Get the actual value reflected by this mirror.
   * @return {value} The value reflected by this mirror
   */
  ValueMirror.prototype.value = function() {
    return this.value_;
  };
  
  
  /**
   * Mirror object for Undefined.
   * @constructor
   * @extends ValueMirror
   */
  function UndefinedMirror() {
    %_CallFunction(this, UNDEFINED_TYPE, void 0, ValueMirror);
  }
  inherits(UndefinedMirror, ValueMirror);
  
  
  UndefinedMirror.prototype.toText = function() {
    return 'undefined';
  };
  
  
  /**
   * Mirror object for null.
   * @constructor
   * @extends ValueMirror
   */
  function NullMirror() {
    %_CallFunction(this, NULL_TYPE, null, ValueMirror);
  }
  inherits(NullMirror, ValueMirror);
  
  
  NullMirror.prototype.toText = function() {
    return 'null';
  };
  
  
  /**
   * Mirror object for boolean values.
   * @param {boolean} value The boolean value reflected by this mirror
   * @constructor
   * @extends ValueMirror
   */
  function BooleanMirror(value) {
    %_CallFunction(this, BOOLEAN_TYPE, value, ValueMirror);
  }
  inherits(BooleanMirror, ValueMirror);
  
  
  BooleanMirror.prototype.toText = function() {
    return this.value_ ? 'true' : 'false';
  };
  
  
  /**
   * Mirror object for number values.
   * @param {number} value The number value reflected by this mirror
   * @constructor
   * @extends ValueMirror
   */
  function NumberMirror(value) {
    %_CallFunction(this, NUMBER_TYPE, value, ValueMirror);
  }
  inherits(NumberMirror, ValueMirror);
  
  
  NumberMirror.prototype.toText = function() {
    return %NumberToString(this.value_);
  };
  
  
  /**
   * Mirror object for string values.
   * @param {string} value The string value reflected by this mirror
   * @constructor
   * @extends ValueMirror
   */
  function StringMirror(value) {
    %_CallFunction(this, STRING_TYPE, value, ValueMirror);
  }
  inherits(StringMirror, ValueMirror);
  
  
  StringMirror.prototype.length = function() {
    return this.value_.length;
  };
  
  StringMirror.prototype.getTruncatedValue = function(maxLength) {
    if (maxLength != -1 && this.length() > maxLength) {
      return this.value_.substring(0, maxLength) +
             '... (length: ' + this.length() + ')';
    }
    return this.value_;
  };
  
  StringMirror.prototype.toText = function() {
    return this.getTruncatedValue(kMaxProtocolStringLength);
  };
  
  
  /**
   * Mirror object for objects.
   * @param {object} value The object reflected by this mirror
   * @param {boolean} transient indicate whether this object is transient with a
   *    transient handle
   * @constructor
   * @extends ValueMirror
   */
  function ObjectMirror(value, type, transient) {
    %_CallFunction(this, type || OBJECT_TYPE, value, transient, ValueMirror);
  }
  inherits(ObjectMirror, ValueMirror);
  
  
  ObjectMirror.prototype.className = function() {
    return %_ClassOf(this.value_);
  };
  
  
  ObjectMirror.prototype.constructorFunction = function() {
    return MakeMirror(%DebugGetProperty(this.value_, 'constructor'));
  };
  
  
  ObjectMirror.prototype.prototypeObject = function() {
    return MakeMirror(%DebugGetProperty(this.value_, 'prototype'));
  };
  
  
  ObjectMirror.prototype.protoObject = function() {
    return MakeMirror(%DebugGetPrototype(this.value_));
  };
  
  
  ObjectMirror.prototype.hasNamedInterceptor = function() {
    // Get information on interceptors for this object.
    var x = %GetInterceptorInfo(this.value_);
    return (x & 2) != 0;
  };
  
  
  ObjectMirror.prototype.hasIndexedInterceptor = function() {
    // Get information on interceptors for this object.
    var x = %GetInterceptorInfo(this.value_);
    return (x & 1) != 0;
  };
  
  
  /**
   * Return the property names for this object.
   * @param {number} kind Indicate whether named, indexed or both kinds of
   *     properties are requested
   * @param {number} limit Limit the number of names returend to the specified
         value
   * @return {Array} Property names for this object
   */
  ObjectMirror.prototype.propertyNames = function(kind, limit) {
    // Find kind and limit and allocate array for the result
    kind = kind || PropertyKind.Named | PropertyKind.Indexed;
  
    var propertyNames;
    var elementNames;
    var total = 0;
  
    // Find all the named properties.
    if (kind & PropertyKind.Named) {
      // Get the local property names.
      propertyNames = %GetLocalPropertyNames(this.value_);
      total += propertyNames.length;
  
      // Get names for named interceptor properties if any.
      if (this.hasNamedInterceptor() && (kind & PropertyKind.Named)) {
        var namedInterceptorNames =
            %GetNamedInterceptorPropertyNames(this.value_);
        if (namedInterceptorNames) {
          propertyNames = propertyNames.concat(namedInterceptorNames);
          total += namedInterceptorNames.length;
        }
      }
    }
  
    // Find all the indexed properties.
    if (kind & PropertyKind.Indexed) {
      // Get the local element names.
      elementNames = %GetLocalElementNames(this.value_);
      total += elementNames.length;
  
      // Get names for indexed interceptor properties.
      if (this.hasIndexedInterceptor() && (kind & PropertyKind.Indexed)) {
        var indexedInterceptorNames =
            %GetIndexedInterceptorElementNames(this.value_);
        if (indexedInterceptorNames) {
          elementNames = elementNames.concat(indexedInterceptorNames);
          total += indexedInterceptorNames.length;
        }
      }
    }
    limit = Math.min(limit || total, total);
  
    var names = new Array(limit);
    var index = 0;
  
    // Copy names for named properties.
    if (kind & PropertyKind.Named) {
      for (var i = 0; index < limit && i < propertyNames.length; i++) {
        names[index++] = propertyNames[i];
      }
    }
  
    // Copy names for indexed properties.
    if (kind & PropertyKind.Indexed) {
      for (var i = 0; index < limit && i < elementNames.length; i++) {
        names[index++] = elementNames[i];
      }
    }
  
    return names;
  };
  
  
  /**
   * Return the properties for this object as an array of PropertyMirror objects.
   * @param {number} kind Indicate whether named, indexed or both kinds of
   *     properties are requested
   * @param {number} limit Limit the number of properties returend to the
         specified value
   * @return {Array} Property mirrors for this object
   */
  ObjectMirror.prototype.properties = function(kind, limit) {
    var names = this.propertyNames(kind, limit);
    var properties = new Array(names.length);
    for (var i = 0; i < names.length; i++) {
      properties[i] = this.property(names[i]);
    }
  
    return properties;
  };
  
  
  ObjectMirror.prototype.property = function(name) {
    var details = %DebugGetPropertyDetails(this.value_, %ToString(name));
    if (details) {
      return new PropertyMirror(this, name, details);
    }
  
    // Nothing found.
    return GetUndefinedMirror();
  };
  
  
  
  /**
   * Try to find a property from its value.
   * @param {Mirror} value The property value to look for
   * @return {PropertyMirror} The property with the specified value. If no
   *     property was found with the specified value UndefinedMirror is returned
   */
  ObjectMirror.prototype.lookupProperty = function(value) {
    var properties = this.properties();
  
    // Look for property value in properties.
    for (var i = 0; i < properties.length; i++) {
  
      // Skip properties which are defined through assessors.
      var property = properties[i];
      if (property.propertyType() != PropertyType.Callbacks) {
        if (%_ObjectEquals(property.value_, value.value_)) {
          return property;
        }
      }
    }
  
    // Nothing found.
    return GetUndefinedMirror();
  };
  
  
  /**
   * Returns objects which has direct references to this object
   * @param {number} opt_max_objects Optional parameter specifying the maximum
   *     number of referencing objects to return.
   * @return {Array} The objects which has direct references to this object.
   */
  ObjectMirror.prototype.referencedBy = function(opt_max_objects) {
    // Find all objects with direct references to this object.
    var result = %DebugReferencedBy(this.value_,
                                    Mirror.prototype, opt_max_objects || 0);
  
    // Make mirrors for all the references found.
    for (var i = 0; i < result.length; i++) {
      result[i] = MakeMirror(result[i]);
    }
  
    return result;
  };
  
  
  ObjectMirror.prototype.toText = function() {
    var name;
    var ctor = this.constructorFunction();
    if (!ctor.isFunction()) {
      name = this.className();
    } else {
      name = ctor.name();
      if (!name) {
        name = this.className();
      }
    }
    return '#<' + name + '>';
  };
  
  
  /**
   * Mirror object for functions.
   * @param {function} value The function object reflected by this mirror.
   * @constructor
   * @extends ObjectMirror
   */
  function FunctionMirror(value) {
    %_CallFunction(this, value, FUNCTION_TYPE, ObjectMirror);
    this.resolved_ = true;
  }
  inherits(FunctionMirror, ObjectMirror);
  
  
  /**
   * Returns whether the function is resolved.
   * @return {boolean} True if the function is resolved. Unresolved functions can
   *     only originate as functions from stack frames
   */
  FunctionMirror.prototype.resolved = function() {
    return this.resolved_;
  };
  
  
  /**
   * Returns the name of the function.
   * @return {string} Name of the function
   */
  FunctionMirror.prototype.name = function() {
    return %FunctionGetName(this.value_);
  };
  
  
  /**
   * Returns the inferred name of the function.
   * @return {string} Name of the function
   */
  FunctionMirror.prototype.inferredName = function() {
    return %FunctionGetInferredName(this.value_);
  };
  
  
  /**
   * Returns the source code for the function.
   * @return {string or undefined} The source code for the function. If the
   *     function is not resolved undefined will be returned.
   */
  FunctionMirror.prototype.source = function() {
    // Return source if function is resolved. Otherwise just fall through to
    // return undefined.
    if (this.resolved()) {
      return builtins.FunctionSourceString(this.value_);
    }
  };
  
  
  /**
   * Returns the script object for the function.
   * @return {ScriptMirror or undefined} Script object for the function or
   *     undefined if the function has no script
   */
  FunctionMirror.prototype.script = function() {
    // Return script if function is resolved. Otherwise just fall through
    // to return undefined.
    if (this.resolved()) {
      var script = %FunctionGetScript(this.value_);
      if (script) {
        return MakeMirror(script);
      }
    }
  };
  
  
  /**
   * Returns the script source position for the function. Only makes sense
   * for functions which has a script defined.
   * @return {Number or undefined} in-script position for the function
   */
  FunctionMirror.prototype.sourcePosition_ = function() {
    // Return script if function is resolved. Otherwise just fall through
    // to return undefined.
    if (this.resolved()) {
      return %FunctionGetScriptSourcePosition(this.value_);
    }
  };
  
  
  /**
   * Returns the script source location object for the function. Only makes sense
   * for functions which has a script defined.
   * @return {Location or undefined} in-script location for the function begin
   */
  FunctionMirror.prototype.sourceLocation = function() {
    if (this.resolved() && this.script()) {
      return this.script().locationFromPosition(this.sourcePosition_(),
                                                true);
    }
  };
  
  
  /**
   * Returns objects constructed by this function.
   * @param {number} opt_max_instances Optional parameter specifying the maximum
   *     number of instances to return.
   * @return {Array or undefined} The objects constructed by this function.
   */
  FunctionMirror.prototype.constructedBy = function(opt_max_instances) {
    if (this.resolved()) {
      // Find all objects constructed from this function.
      var result = %DebugConstructedBy(this.value_, opt_max_instances || 0);
  
      // Make mirrors for all the instances found.
      for (var i = 0; i < result.length; i++) {
        result[i] = MakeMirror(result[i]);
      }
  
      return result;
    } else {
      return [];
    }
  };
  
  
  FunctionMirror.prototype.toText = function() {
    return this.source();
  };
  
  
  /**
   * Mirror object for unresolved functions.
   * @param {string} value The name for the unresolved function reflected by this
   *     mirror.
   * @constructor
   * @extends ObjectMirror
   */
  function UnresolvedFunctionMirror(value) {
    // Construct this using the ValueMirror as an unresolved function is not a
    // real object but just a string.
    %_CallFunction(this, FUNCTION_TYPE, value, ValueMirror);
    this.propertyCount_ = 0;
    this.elementCount_ = 0;
    this.resolved_ = false;
  }
  inherits(UnresolvedFunctionMirror, FunctionMirror);
  
  
  UnresolvedFunctionMirror.prototype.className = function() {
    return 'Function';
  };
  
  
  UnresolvedFunctionMirror.prototype.constructorFunction = function() {
    return GetUndefinedMirror();
  };
  
  
  UnresolvedFunctionMirror.prototype.prototypeObject = function() {
    return GetUndefinedMirror();
  };
  
  
  UnresolvedFunctionMirror.prototype.protoObject = function() {
    return GetUndefinedMirror();
  };
  
  
  UnresolvedFunctionMirror.prototype.name = function() {
    return this.value_;
  };
  
  
  UnresolvedFunctionMirror.prototype.inferredName = function() {
    return undefined;
  };
  
  
  UnresolvedFunctionMirror.prototype.propertyNames = function(kind, limit) {
    return [];
  };
  
  
  /**
   * Mirror object for arrays.
   * @param {Array} value The Array object reflected by this mirror
   * @constructor
   * @extends ObjectMirror
   */
  function ArrayMirror(value) {
    %_CallFunction(this, value, ObjectMirror);
  }
  inherits(ArrayMirror, ObjectMirror);
  
  
  ArrayMirror.prototype.length = function() {
    return this.value_.length;
  };
  
  
  ArrayMirror.prototype.indexedPropertiesFromRange = function(opt_from_index,
                                                              opt_to_index) {
    var from_index = opt_from_index || 0;
    var to_index = opt_to_index || this.length() - 1;
    if (from_index > to_index) return new Array();
    var values = new Array(to_index - from_index + 1);
    for (var i = from_index; i <= to_index; i++) {
      var details = %DebugGetPropertyDetails(this.value_, %ToString(i));
      var value;
      if (details) {
        value = new PropertyMirror(this, i, details);
      } else {
        value = GetUndefinedMirror();
      }
      values[i - from_index] = value;
    }
    return values;
  };
  
  
  /**
   * Mirror object for dates.
   * @param {Date} value The Date object reflected by this mirror
   * @constructor
   * @extends ObjectMirror
   */
  function DateMirror(value) {
    %_CallFunction(this, value, ObjectMirror);
  }
  inherits(DateMirror, ObjectMirror);
  
  
  DateMirror.prototype.toText = function() {
    var s = JSON.stringify(this.value_);
    return s.substring(1, s.length - 1);  // cut quotes
  };
  
  
  /**
   * Mirror object for regular expressions.
   * @param {RegExp} value The RegExp object reflected by this mirror
   * @constructor
   * @extends ObjectMirror
   */
  function RegExpMirror(value) {
    %_CallFunction(this, value, REGEXP_TYPE, ObjectMirror);
  }
  inherits(RegExpMirror, ObjectMirror);
  
  
  /**
   * Returns the source to the regular expression.
   * @return {string or undefined} The source to the regular expression
   */
  RegExpMirror.prototype.source = function() {
    return this.value_.source;
  };
  
  
  /**
   * Returns whether this regular expression has the global (g) flag set.
   * @return {boolean} Value of the global flag
   */
  RegExpMirror.prototype.global = function() {
    return this.value_.global;
  };
  
  
  /**
   * Returns whether this regular expression has the ignore case (i) flag set.
   * @return {boolean} Value of the ignore case flag
   */
  RegExpMirror.prototype.ignoreCase = function() {
    return this.value_.ignoreCase;
  };
  
  
  /**
   * Returns whether this regular expression has the multiline (m) flag set.
   * @return {boolean} Value of the multiline flag
   */
  RegExpMirror.prototype.multiline = function() {
    return this.value_.multiline;
  };
  
  
  RegExpMirror.prototype.toText = function() {
    // Simpel to text which is used when on specialization in subclass.
    return "/" + this.source() + "/";
  };
  
  
  /**
   * Mirror object for error objects.
   * @param {Error} value The error object reflected by this mirror
   * @constructor
   * @extends ObjectMirror
   */
  function ErrorMirror(value) {
    %_CallFunction(this, value, ERROR_TYPE, ObjectMirror);
  }
  inherits(ErrorMirror, ObjectMirror);
  
  
  /**
   * Returns the message for this eror object.
   * @return {string or undefined} The message for this eror object
   */
  ErrorMirror.prototype.message = function() {
    return this.value_.message;
  };
  
  
  ErrorMirror.prototype.toText = function() {
    // Use the same text representation as in messages.js.
    var text;
    try {
      str = %_CallFunction(this.value_, builtins.ErrorToString);
    } catch (e) {
      str = '#<Error>';
    }
    return str;
  };
  
  
  /**
   * Base mirror object for properties.
   * @param {ObjectMirror} mirror The mirror object having this property
   * @param {string} name The name of the property
   * @param {Array} details Details about the property
   * @constructor
   * @extends Mirror
   */
  function PropertyMirror(mirror, name, details) {
    %_CallFunction(this, PROPERTY_TYPE, Mirror);
    this.mirror_ = mirror;
    this.name_ = name;
    this.value_ = details[0];
    this.details_ = details[1];
    if (details.length > 2) {
      this.exception_ = details[2];
      this.getter_ = details[3];
      this.setter_ = details[4];
    }
  }
  inherits(PropertyMirror, Mirror);
  
  
  PropertyMirror.prototype.isReadOnly = function() {
    return (this.attributes() & PropertyAttribute.ReadOnly) != 0;
  };
  
  
  PropertyMirror.prototype.isEnum = function() {
    return (this.attributes() & PropertyAttribute.DontEnum) == 0;
  };
  
  
  PropertyMirror.prototype.canDelete = function() {
    return (this.attributes() & PropertyAttribute.DontDelete) == 0;
  };
  
  
  PropertyMirror.prototype.name = function() {
    return this.name_;
  };
  
  
  PropertyMirror.prototype.isIndexed = function() {
    for (var i = 0; i < this.name_.length; i++) {
      if (this.name_[i] < '0' || '9' < this.name_[i]) {
        return false;
      }
    }
    return true;
  };
  
  
  PropertyMirror.prototype.value = function() {
    return MakeMirror(this.value_, false);
  };
  
  
  /**
   * Returns whether this property value is an exception.
   * @return {booolean} True if this property value is an exception
   */
  PropertyMirror.prototype.isException = function() {
    return this.exception_ ? true : false;
  };
  
  
  PropertyMirror.prototype.attributes = function() {
    return %DebugPropertyAttributesFromDetails(this.details_);
  };
  
  
  PropertyMirror.prototype.propertyType = function() {
    return %DebugPropertyTypeFromDetails(this.details_);
  };
  
  
  PropertyMirror.prototype.insertionIndex = function() {
    return %DebugPropertyIndexFromDetails(this.details_);
  };
  
  
  /**
   * Returns whether this property has a getter defined through __defineGetter__.
   * @return {booolean} True if this property has a getter
   */
  PropertyMirror.prototype.hasGetter = function() {
    return this.getter_ ? true : false;
  };
  
  
  /**
   * Returns whether this property has a setter defined through __defineSetter__.
   * @return {booolean} True if this property has a setter
   */
  PropertyMirror.prototype.hasSetter = function() {
    return this.setter_ ? true : false;
  };
  
  
  /**
   * Returns the getter for this property defined through __defineGetter__.
   * @return {Mirror} FunctionMirror reflecting the getter function or
   *     UndefinedMirror if there is no getter for this property
   */
  PropertyMirror.prototype.getter = function() {
    if (this.hasGetter()) {
      return MakeMirror(this.getter_);
    } else {
      return GetUndefinedMirror();
    }
  };
  
  
  /**
   * Returns the setter for this property defined through __defineSetter__.
   * @return {Mirror} FunctionMirror reflecting the setter function or
   *     UndefinedMirror if there is no setter for this property
   */
  PropertyMirror.prototype.setter = function() {
    if (this.hasSetter()) {
      return MakeMirror(this.setter_);
    } else {
      return GetUndefinedMirror();
    }
  };
  
  
  /**
   * Returns whether this property is natively implemented by the host or a set
   * through JavaScript code.
   * @return {boolean} True if the property is
   *     UndefinedMirror if there is no setter for this property
   */
  PropertyMirror.prototype.isNative = function() {
    return (this.propertyType() == PropertyType.Interceptor) ||
           ((this.propertyType() == PropertyType.Callbacks) &&
            !this.hasGetter() && !this.hasSetter());
  };
  
  
  var kFrameDetailsFrameIdIndex = 0;
  var kFrameDetailsReceiverIndex = 1;
  var kFrameDetailsFunctionIndex = 2;
  var kFrameDetailsArgumentCountIndex = 3;
  var kFrameDetailsLocalCountIndex = 4;
  var kFrameDetailsSourcePositionIndex = 5;
  var kFrameDetailsConstructCallIndex = 6;
  var kFrameDetailsAtReturnIndex = 7;
  var kFrameDetailsFlagsIndex = 8;
  var kFrameDetailsFirstDynamicIndex = 9;
  
  var kFrameDetailsNameIndex = 0;
  var kFrameDetailsValueIndex = 1;
  var kFrameDetailsNameValueSize = 2;
  
  var kFrameDetailsFlagDebuggerFrameMask = 1 << 0;
  var kFrameDetailsFlagOptimizedFrameMask = 1 << 1;
  var kFrameDetailsFlagInlinedFrameIndexMask = 7 << 2;
  
  /**
   * Wrapper for the frame details information retreived from the VM. The frame
   * details from the VM is an array with the following content. See runtime.cc
   * Runtime_GetFrameDetails.
   *     0: Id
   *     1: Receiver
   *     2: Function
   *     3: Argument count
   *     4: Local count
   *     5: Source position
   *     6: Construct call
   *     7: Is at return
   *     8: Flags (debugger frame, optimized frame, inlined frame index)
   *     Arguments name, value
   *     Locals name, value
   *     Return value if any
   * @param {number} break_id Current break id
   * @param {number} index Frame number
   * @constructor
   */
  function FrameDetails(break_id, index) {
    this.break_id_ = break_id;
    this.details_ = %GetFrameDetails(break_id, index);
  }
  
  
  FrameDetails.prototype.frameId = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsFrameIdIndex];
  };
  
  
  FrameDetails.prototype.receiver = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsReceiverIndex];
  };
  
  
  FrameDetails.prototype.func = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsFunctionIndex];
  };
  
  
  FrameDetails.prototype.isConstructCall = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsConstructCallIndex];
  };
  
  
  FrameDetails.prototype.isAtReturn = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsAtReturnIndex];
  };
  
  
  FrameDetails.prototype.isDebuggerFrame = function() {
    %CheckExecutionState(this.break_id_);
    var f = kFrameDetailsFlagDebuggerFrameMask;
    return (this.details_[kFrameDetailsFlagsIndex] & f) == f;
  };
  
  
  FrameDetails.prototype.isOptimizedFrame = function() {
    %CheckExecutionState(this.break_id_);
    var f = kFrameDetailsFlagOptimizedFrameMask;
    return (this.details_[kFrameDetailsFlagsIndex] & f) == f;
  };
  
  
  FrameDetails.prototype.isInlinedFrame = function() {
    return this.inlinedFrameIndex() > 0;
  };
  
  
  FrameDetails.prototype.inlinedFrameIndex = function() {
    %CheckExecutionState(this.break_id_);
    var f = kFrameDetailsFlagInlinedFrameIndexMask;
    return (this.details_[kFrameDetailsFlagsIndex] & f) >> 2;
  };
  
  
  FrameDetails.prototype.argumentCount = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsArgumentCountIndex];
  };
  
  
  FrameDetails.prototype.argumentName = function(index) {
    %CheckExecutionState(this.break_id_);
    if (index >= 0 && index < this.argumentCount()) {
      return this.details_[kFrameDetailsFirstDynamicIndex +
                           index * kFrameDetailsNameValueSize +
                           kFrameDetailsNameIndex];
    }
  };
  
  
  FrameDetails.prototype.argumentValue = function(index) {
    %CheckExecutionState(this.break_id_);
    if (index >= 0 && index < this.argumentCount()) {
      return this.details_[kFrameDetailsFirstDynamicIndex +
                           index * kFrameDetailsNameValueSize +
                           kFrameDetailsValueIndex];
    }
  };
  
  
  FrameDetails.prototype.localCount = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsLocalCountIndex];
  };
  
  
  FrameDetails.prototype.sourcePosition = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kFrameDetailsSourcePositionIndex];
  };
  
  
  FrameDetails.prototype.localName = function(index) {
    %CheckExecutionState(this.break_id_);
    if (index >= 0 && index < this.localCount()) {
      var locals_offset = kFrameDetailsFirstDynamicIndex +
                          this.argumentCount() * kFrameDetailsNameValueSize;
      return this.details_[locals_offset +
                           index * kFrameDetailsNameValueSize +
                           kFrameDetailsNameIndex];
    }
  };
  
  
  FrameDetails.prototype.localValue = function(index) {
    %CheckExecutionState(this.break_id_);
    if (index >= 0 && index < this.localCount()) {
      var locals_offset = kFrameDetailsFirstDynamicIndex +
                          this.argumentCount() * kFrameDetailsNameValueSize;
      return this.details_[locals_offset +
                           index * kFrameDetailsNameValueSize +
                           kFrameDetailsValueIndex];
    }
  };
  
  
  FrameDetails.prototype.returnValue = function() {
    %CheckExecutionState(this.break_id_);
    var return_value_offset =
        kFrameDetailsFirstDynamicIndex +
        (this.argumentCount() + this.localCount()) * kFrameDetailsNameValueSize;
    if (this.details_[kFrameDetailsAtReturnIndex]) {
      return this.details_[return_value_offset];
    }
  };
  
  
  FrameDetails.prototype.scopeCount = function() {
    return %GetScopeCount(this.break_id_, this.frameId());
  };
  
  
  /**
   * Mirror object for stack frames.
   * @param {number} break_id The break id in the VM for which this frame is
         valid
   * @param {number} index The frame index (top frame is index 0)
   * @constructor
   * @extends Mirror
   */
  function FrameMirror(break_id, index) {
    %_CallFunction(this, FRAME_TYPE, Mirror);
    this.break_id_ = break_id;
    this.index_ = index;
    this.details_ = new FrameDetails(break_id, index);
  }
  inherits(FrameMirror, Mirror);
  
  
  FrameMirror.prototype.index = function() {
    return this.index_;
  };
  
  
  FrameMirror.prototype.func = function() {
    // Get the function for this frame from the VM.
    var f = this.details_.func();
  
    // Create a function mirror. NOTE: MakeMirror cannot be used here as the
    // value returned from the VM might be a string if the function for the
    // frame is unresolved.
    if (IS_FUNCTION(f)) {
      return MakeMirror(f);
    } else {
      return new UnresolvedFunctionMirror(f);
    }
  };
  
  
  FrameMirror.prototype.receiver = function() {
    return MakeMirror(this.details_.receiver());
  };
  
  
  FrameMirror.prototype.isConstructCall = function() {
    return this.details_.isConstructCall();
  };
  
  
  FrameMirror.prototype.isAtReturn = function() {
    return this.details_.isAtReturn();
  };
  
  
  FrameMirror.prototype.isDebuggerFrame = function() {
    return this.details_.isDebuggerFrame();
  };
  
  
  FrameMirror.prototype.isOptimizedFrame = function() {
    return this.details_.isOptimizedFrame();
  };
  
  
  FrameMirror.prototype.isInlinedFrame = function() {
    return this.details_.isInlinedFrame();
  };
  
  
  FrameMirror.prototype.inlinedFrameIndex = function() {
    return this.details_.inlinedFrameIndex();
  };
  
  
  FrameMirror.prototype.argumentCount = function() {
    return this.details_.argumentCount();
  };
  
  
  FrameMirror.prototype.argumentName = function(index) {
    return this.details_.argumentName(index);
  };
  
  
  FrameMirror.prototype.argumentValue = function(index) {
    return MakeMirror(this.details_.argumentValue(index));
  };
  
  
  FrameMirror.prototype.localCount = function() {
    return this.details_.localCount();
  };
  
  
  FrameMirror.prototype.localName = function(index) {
    return this.details_.localName(index);
  };
  
  
  FrameMirror.prototype.localValue = function(index) {
    return MakeMirror(this.details_.localValue(index));
  };
  
  
  FrameMirror.prototype.returnValue = function() {
    return MakeMirror(this.details_.returnValue());
  };
  
  
  FrameMirror.prototype.sourcePosition = function() {
    return this.details_.sourcePosition();
  };
  
  
  FrameMirror.prototype.sourceLocation = function() {
    if (this.func().resolved() && this.func().script()) {
      return this.func().script().locationFromPosition(this.sourcePosition(),
                                                       true);
    }
  };
  
  
  FrameMirror.prototype.sourceLine = function() {
    if (this.func().resolved()) {
      var location = this.sourceLocation();
      if (location) {
        return location.line;
      }
    }
  };
  
  
  FrameMirror.prototype.sourceColumn = function() {
    if (this.func().resolved()) {
      var location = this.sourceLocation();
      if (location) {
        return location.column;
      }
    }
  };
  
  
  FrameMirror.prototype.sourceLineText = function() {
    if (this.func().resolved()) {
      var location = this.sourceLocation();
      if (location) {
        return location.sourceText();
      }
    }
  };
  
  
  FrameMirror.prototype.scopeCount = function() {
    return this.details_.scopeCount();
  };
  
  
  FrameMirror.prototype.scope = function(index) {
    return new ScopeMirror(this, index);
  };
  
  
  FrameMirror.prototype.evaluate = function(source, disable_break,
                                            opt_context_object) {
    var result = %DebugEvaluate(this.break_id_,
                                this.details_.frameId(),
                                this.details_.inlinedFrameIndex(),
                                source,
                                Boolean(disable_break),
                                opt_context_object);
    return MakeMirror(result);
  };
  
  
  FrameMirror.prototype.invocationText = function() {
    // Format frame invoaction (receiver, function and arguments).
    var result = '';
    var func = this.func();
    var receiver = this.receiver();
    if (this.isConstructCall()) {
      // For constructor frames display new followed by the function name.
      result += 'new ';
      result += func.name() ? func.name() : '[anonymous]';
    } else if (this.isDebuggerFrame()) {
      result += '[debugger]';
    } else {
      // If the receiver has a className which is 'global' don't display it.
      var display_receiver =
        !receiver.className || (receiver.className() != 'global');
      if (display_receiver) {
        result += receiver.toText();
      }
      // Try to find the function as a property in the receiver. Include the
      // prototype chain in the lookup.
      var property = GetUndefinedMirror();
      if (receiver.isObject()) {
        for (var r = receiver;
             !r.isNull() && property.isUndefined();
             r = r.protoObject()) {
          property = r.lookupProperty(func);
        }
      }
      if (!property.isUndefined()) {
        // The function invoked was found on the receiver. Use the property name
        // for the backtrace.
        if (!property.isIndexed()) {
          if (display_receiver) {
            result += '.';
          }
          result += property.name();
        } else {
          result += '[';
          result += property.name();
          result += ']';
        }
        // Also known as - if the name in the function doesn't match the name
        // under which it was looked up.
        if (func.name() && func.name() != property.name()) {
          result += '(aka ' + func.name() + ')';
        }
      } else {
        // The function invoked was not found on the receiver. Use the function
        // name if available for the backtrace.
        if (display_receiver) {
          result += '.';
        }
        result += func.name() ? func.name() : '[anonymous]';
      }
    }
  
    // Render arguments for normal frames.
    if (!this.isDebuggerFrame()) {
      result += '(';
      for (var i = 0; i < this.argumentCount(); i++) {
        if (i != 0) result += ', ';
        if (this.argumentName(i)) {
          result += this.argumentName(i);
          result += '=';
        }
        result += this.argumentValue(i).toText();
      }
      result += ')';
    }
  
    if (this.isAtReturn()) {
      result += ' returning ';
      result += this.returnValue().toText();
    }
  
    return result;
  };
  
  
  FrameMirror.prototype.sourceAndPositionText = function() {
    // Format source and position.
    var result = '';
    var func = this.func();
    if (func.resolved()) {
      if (func.script()) {
        if (func.script().name()) {
          result += func.script().name();
        } else {
          result += '[unnamed]';
        }
        if (!this.isDebuggerFrame()) {
          var location = this.sourceLocation();
          result += ' line ';
          result += !IS_UNDEFINED(location) ? (location.line + 1) : '?';
          result += ' column ';
          result += !IS_UNDEFINED(location) ? (location.column + 1) : '?';
          if (!IS_UNDEFINED(this.sourcePosition())) {
            result += ' (position ' + (this.sourcePosition() + 1) + ')';
          }
        }
      } else {
        result += '[no source]';
      }
    } else {
      result += '[unresolved]';
    }
  
    return result;
  };
  
  
  FrameMirror.prototype.localsText = function() {
    // Format local variables.
    var result = '';
    var locals_count = this.localCount();
    if (locals_count > 0) {
      for (var i = 0; i < locals_count; ++i) {
        result += '      var ';
        result += this.localName(i);
        result += ' = ';
        result += this.localValue(i).toText();
        if (i < locals_count - 1) result += '\n';
      }
    }
  
    return result;
  };
  
  
  FrameMirror.prototype.toText = function(opt_locals) {
    var result = '';
    result += '#' + (this.index() <= 9 ? '0' : '') + this.index();
    result += ' ';
    result += this.invocationText();
    result += ' ';
    result += this.sourceAndPositionText();
    if (opt_locals) {
      result += '\n';
      result += this.localsText();
    }
    return result;
  };
  
  
  var kScopeDetailsTypeIndex = 0;
  var kScopeDetailsObjectIndex = 1;
  
  function ScopeDetails(frame, index) {
    this.break_id_ = frame.break_id_;
    this.details_ = %GetScopeDetails(frame.break_id_,
                                     frame.details_.frameId(),
                                     frame.details_.inlinedFrameIndex(),
                                     index);
  }
  
  
  ScopeDetails.prototype.type = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kScopeDetailsTypeIndex];
  };
  
  
  ScopeDetails.prototype.object = function() {
    %CheckExecutionState(this.break_id_);
    return this.details_[kScopeDetailsObjectIndex];
  };
  
  
  /**
   * Mirror object for scope.
   * @param {FrameMirror} frame The frame this scope is a part of
   * @param {number} index The scope index in the frame
   * @constructor
   * @extends Mirror
   */
  function ScopeMirror(frame, index) {
    %_CallFunction(this, SCOPE_TYPE, Mirror);
    this.frame_index_ = frame.index_;
    this.scope_index_ = index;
    this.details_ = new ScopeDetails(frame, index);
  }
  inherits(ScopeMirror, Mirror);
  
  
  ScopeMirror.prototype.frameIndex = function() {
    return this.frame_index_;
  };
  
  
  ScopeMirror.prototype.scopeIndex = function() {
    return this.scope_index_;
  };
  
  
  ScopeMirror.prototype.scopeType = function() {
    return this.details_.type();
  };
  
  
  ScopeMirror.prototype.scopeObject = function() {
    // For local and closure scopes create a transient mirror as these objects are
    // created on the fly materializing the local or closure scopes and
    // therefore will not preserve identity.
    var transient = this.scopeType() == ScopeType.Local ||
                    this.scopeType() == ScopeType.Closure;
    return MakeMirror(this.details_.object(), transient);
  };
  
  
  /**
   * Mirror object for script source.
   * @param {Script} script The script object
   * @constructor
   * @extends Mirror
   */
  function ScriptMirror(script) {
    %_CallFunction(this, SCRIPT_TYPE, Mirror);
    this.script_ = script;
    this.context_ = new ContextMirror(script.context_data);
    this.allocateHandle_();
  }
  inherits(ScriptMirror, Mirror);
  
  
  ScriptMirror.prototype.value = function() {
    return this.script_;
  };
  
  
  ScriptMirror.prototype.name = function() {
    return this.script_.name || this.script_.nameOrSourceURL();
  };
  
  
  ScriptMirror.prototype.id = function() {
    return this.script_.id;
  };
  
  
  ScriptMirror.prototype.source = function() {
    return this.script_.source;
  };
  
  
  ScriptMirror.prototype.setSource = function(source) {
    %DebugSetScriptSource(this.script_, source);
  };
  
  
  ScriptMirror.prototype.lineOffset = function() {
    return this.script_.line_offset;
  };
  
  
  ScriptMirror.prototype.columnOffset = function() {
    return this.script_.column_offset;
  };
  
  
  ScriptMirror.prototype.data = function() {
    return this.script_.data;
  };
  
  
  ScriptMirror.prototype.scriptType = function() {
    return this.script_.type;
  };
  
  
  ScriptMirror.prototype.compilationType = function() {
    return this.script_.compilation_type;
  };
  
  
  ScriptMirror.prototype.lineCount = function() {
    return this.script_.lineCount();
  };
  
  
  ScriptMirror.prototype.locationFromPosition = function(
      position, include_resource_offset) {
    return this.script_.locationFromPosition(position, include_resource_offset);
  };
  
  
  ScriptMirror.prototype.sourceSlice = function (opt_from_line, opt_to_line) {
    return this.script_.sourceSlice(opt_from_line, opt_to_line);
  };
  
  
  ScriptMirror.prototype.context = function() {
    return this.context_;
  };
  
  
  ScriptMirror.prototype.evalFromScript = function() {
    return MakeMirror(this.script_.eval_from_script);
  };
  
  
  ScriptMirror.prototype.evalFromFunctionName = function() {
    return MakeMirror(this.script_.eval_from_function_name);
  };
  
  
  ScriptMirror.prototype.evalFromLocation = function() {
    var eval_from_script = this.evalFromScript();
    if (!eval_from_script.isUndefined()) {
      var position = this.script_.eval_from_script_position;
      return eval_from_script.locationFromPosition(position, true);
    }
  };
  
  
  ScriptMirror.prototype.toText = function() {
    var result = '';
    result += this.name();
    result += ' (lines: ';
    if (this.lineOffset() > 0) {
      result += this.lineOffset();
      result += '-';
      result += this.lineOffset() + this.lineCount() - 1;
    } else {
      result += this.lineCount();
    }
    result += ')';
    return result;
  };
  
  
  /**
   * Mirror object for context.
   * @param {Object} data The context data
   * @constructor
   * @extends Mirror
   */
  function ContextMirror(data) {
    %_CallFunction(this, CONTEXT_TYPE, Mirror);
    this.data_ = data;
    this.allocateHandle_();
  }
  inherits(ContextMirror, Mirror);
  
  
  ContextMirror.prototype.data = function() {
    return this.data_;
  };
  
  
  /**
   * Returns a mirror serializer
   *
   * @param {boolean} details Set to true to include details
   * @param {Object} options Options comtrolling the serialization
   *     The following options can be set:
   *       includeSource: include ths full source of scripts
   * @returns {MirrorSerializer} mirror serializer
   */
  function MakeMirrorSerializer(details, options) {
    return new JSONProtocolSerializer(details, options);
  }
  
  
  /**
   * Object for serializing a mirror objects and its direct references.
   * @param {boolean} details Indicates whether to include details for the mirror
   *     serialized
   * @constructor
   */
  function JSONProtocolSerializer(details, options) {
    this.details_ = details;
    this.options_ = options;
    this.mirrors_ = [ ];
  }
  
  
  /**
   * Returns a serialization of an object reference. The referenced object are
   * added to the serialization state.
   *
   * @param {Mirror} mirror The mirror to serialize
   * @returns {String} JSON serialization
   */
  JSONProtocolSerializer.prototype.serializeReference = function(mirror) {
    return this.serialize_(mirror, true, true);
  };
  
  
  /**
   * Returns a serialization of an object value. The referenced objects are
   * added to the serialization state.
   *
   * @param {Mirror} mirror The mirror to serialize
   * @returns {String} JSON serialization
   */
  JSONProtocolSerializer.prototype.serializeValue = function(mirror) {
    var json = this.serialize_(mirror, false, true);
    return json;
  };
  
  
  /**
   * Returns a serialization of all the objects referenced.
   *
   * @param {Mirror} mirror The mirror to serialize.
   * @returns {Array.<Object>} Array of the referenced objects converted to
   *     protcol objects.
   */
  JSONProtocolSerializer.prototype.serializeReferencedObjects = function() {
    // Collect the protocol representation of the referenced objects in an array.
    var content = [];
  
    // Get the number of referenced objects.
    var count = this.mirrors_.length;
  
    for (var i = 0; i < count; i++) {
      content.push(this.serialize_(this.mirrors_[i], false, false));
    }
  
    return content;
  };
  
  
  JSONProtocolSerializer.prototype.includeSource_ = function() {
    return this.options_ && this.options_.includeSource;
  };
  
  
  JSONProtocolSerializer.prototype.inlineRefs_ = function() {
    return this.options_ && this.options_.inlineRefs;
  };
  
  
  JSONProtocolSerializer.prototype.maxStringLength_ = function() {
    if (IS_UNDEFINED(this.options_) ||
        IS_UNDEFINED(this.options_.maxStringLength)) {
      return kMaxProtocolStringLength;
    }
    return this.options_.maxStringLength;
  };
  
  
  JSONProtocolSerializer.prototype.add_ = function(mirror) {
    // If this mirror is already in the list just return.
    for (var i = 0; i < this.mirrors_.length; i++) {
      if (this.mirrors_[i] === mirror) {
        return;
      }
    }
  
    // Add the mirror to the list of mirrors to be serialized.
    this.mirrors_.push(mirror);
  };
  
  
  /**
   * Formats mirror object to protocol reference object with some data that can
   * be used to display the value in debugger.
   * @param {Mirror} mirror Mirror to serialize.
   * @return {Object} Protocol reference object.
   */
  JSONProtocolSerializer.prototype.serializeReferenceWithDisplayData_ =
      function(mirror) {
    var o = {};
    o.ref = mirror.handle();
    o.type = mirror.type();
    switch (mirror.type()) {
      case UNDEFINED_TYPE:
      case NULL_TYPE:
      case BOOLEAN_TYPE:
      case NUMBER_TYPE:
        o.value = mirror.value();
        break;
      case STRING_TYPE:
        o.value = mirror.getTruncatedValue(this.maxStringLength_());
        break;
      case FUNCTION_TYPE:
        o.name = mirror.name();
        o.inferredName = mirror.inferredName();
        if (mirror.script()) {
          o.scriptId = mirror.script().id();
        }
        break;
      case ERROR_TYPE:
      case REGEXP_TYPE:
        o.value = mirror.toText();
        break;
      case OBJECT_TYPE:
        o.className = mirror.className();
        break;
    }
    return o;
  };
  
  
  JSONProtocolSerializer.prototype.serialize_ = function(mirror, reference,
                                                         details) {
    // If serializing a reference to a mirror just return the reference and add
    // the mirror to the referenced mirrors.
    if (reference &&
        (mirror.isValue() || mirror.isScript() || mirror.isContext())) {
      if (this.inlineRefs_() && mirror.isValue()) {
        return this.serializeReferenceWithDisplayData_(mirror);
      } else {
        this.add_(mirror);
        return {'ref' : mirror.handle()};
      }
    }
  
    // Collect the JSON property/value pairs.
    var content = {};
  
    // Add the mirror handle.
    if (mirror.isValue() || mirror.isScript() || mirror.isContext()) {
      content.handle = mirror.handle();
    }
  
    // Always add the type.
    content.type = mirror.type();
  
    switch (mirror.type()) {
      case UNDEFINED_TYPE:
      case NULL_TYPE:
        // Undefined and null are represented just by their type.
        break;
  
      case BOOLEAN_TYPE:
        // Boolean values are simply represented by their value.
        content.value = mirror.value();
        break;
  
      case NUMBER_TYPE:
        // Number values are simply represented by their value.
        content.value = NumberToJSON_(mirror.value());
        break;
  
      case STRING_TYPE:
        // String values might have their value cropped to keep down size.
        if (this.maxStringLength_() != -1 &&
            mirror.length() > this.maxStringLength_()) {
          var str = mirror.getTruncatedValue(this.maxStringLength_());
          content.value = str;
          content.fromIndex = 0;
          content.toIndex = this.maxStringLength_();
        } else {
          content.value = mirror.value();
        }
        content.length = mirror.length();
        break;
  
      case OBJECT_TYPE:
      case FUNCTION_TYPE:
      case ERROR_TYPE:
      case REGEXP_TYPE:
        // Add object representation.
        this.serializeObject_(mirror, content, details);
        break;
  
      case PROPERTY_TYPE:
        throw new Error('PropertyMirror cannot be serialized independeltly');
        break;
  
      case FRAME_TYPE:
        // Add object representation.
        this.serializeFrame_(mirror, content);
        break;
  
      case SCOPE_TYPE:
        // Add object representation.
        this.serializeScope_(mirror, content);
        break;
  
      case SCRIPT_TYPE:
        // Script is represented by id, name and source attributes.
        if (mirror.name()) {
          content.name = mirror.name();
        }
        content.id = mirror.id();
        content.lineOffset = mirror.lineOffset();
        content.columnOffset = mirror.columnOffset();
        content.lineCount = mirror.lineCount();
        if (mirror.data()) {
          content.data = mirror.data();
        }
        if (this.includeSource_()) {
          content.source = mirror.source();
        } else {
          var sourceStart = mirror.source().substring(0, 80);
          content.sourceStart = sourceStart;
        }
        content.sourceLength = mirror.source().length;
        content.scriptType = mirror.scriptType();
        content.compilationType = mirror.compilationType();
        // For compilation type eval emit information on the script from which
        // eval was called if a script is present.
        if (mirror.compilationType() == 1 &&
            mirror.evalFromScript()) {
          content.evalFromScript =
              this.serializeReference(mirror.evalFromScript());
          var evalFromLocation = mirror.evalFromLocation();
          if (evalFromLocation) {
            content.evalFromLocation = { line: evalFromLocation.line,
                                         column: evalFromLocation.column };
          }
          if (mirror.evalFromFunctionName()) {
            content.evalFromFunctionName = mirror.evalFromFunctionName();
          }
        }
        if (mirror.context()) {
          content.context = this.serializeReference(mirror.context());
        }
        break;
  
      case CONTEXT_TYPE:
        content.data = mirror.data();
        break;
    }
  
    // Always add the text representation.
    content.text = mirror.toText();
  
    // Create and return the JSON string.
    return content;
  };
  
  
  /**
   * Serialize object information to the following JSON format.
   *
   *   {"className":"<class name>",
   *    "constructorFunction":{"ref":<number>},
   *    "protoObject":{"ref":<number>},
   *    "prototypeObject":{"ref":<number>},
   *    "namedInterceptor":<boolean>,
   *    "indexedInterceptor":<boolean>,
   *    "properties":[<properties>]}
   */
  JSONProtocolSerializer.prototype.serializeObject_ = function(mirror, content,
                                                               details) {
    // Add general object properties.
    content.className = mirror.className();
    content.constructorFunction =
        this.serializeReference(mirror.constructorFunction());
    content.protoObject = this.serializeReference(mirror.protoObject());
    content.prototypeObject = this.serializeReference(mirror.prototypeObject());
  
    // Add flags to indicate whether there are interceptors.
    if (mirror.hasNamedInterceptor()) {
      content.namedInterceptor = true;
    }
    if (mirror.hasIndexedInterceptor()) {
      content.indexedInterceptor = true;
    }
  
    // Add function specific properties.
    if (mirror.isFunction()) {
      // Add function specific properties.
      content.name = mirror.name();
      if (!IS_UNDEFINED(mirror.inferredName())) {
        content.inferredName = mirror.inferredName();
      }
      content.resolved = mirror.resolved();
      if (mirror.resolved()) {
        content.source = mirror.source();
      }
      if (mirror.script()) {
        content.script = this.serializeReference(mirror.script());
        content.scriptId = mirror.script().id();
  
        serializeLocationFields(mirror.sourceLocation(), content);
      }
    }
  
    // Add date specific properties.
    if (mirror.isDate()) {
      // Add date specific properties.
      content.value = mirror.value();
    }
  
    // Add actual properties - named properties followed by indexed properties.
    var propertyNames = mirror.propertyNames(PropertyKind.Named);
    var propertyIndexes = mirror.propertyNames(PropertyKind.Indexed);
    var p = new Array(propertyNames.length + propertyIndexes.length);
    for (var i = 0; i < propertyNames.length; i++) {
      var propertyMirror = mirror.property(propertyNames[i]);
      p[i] = this.serializeProperty_(propertyMirror);
      if (details) {
        this.add_(propertyMirror.value());
      }
    }
    for (var i = 0; i < propertyIndexes.length; i++) {
      var propertyMirror = mirror.property(propertyIndexes[i]);
      p[propertyNames.length + i] = this.serializeProperty_(propertyMirror);
      if (details) {
        this.add_(propertyMirror.value());
      }
    }
    content.properties = p;
  };
  
  
  /**
   * Serialize location information to the following JSON format:
   *
   *   "position":"<position>",
   *   "line":"<line>",
   *   "column":"<column>",
   *
   * @param {SourceLocation} location The location to serialize, may be undefined.
   */
  function serializeLocationFields (location, content) {
    if (!location) {
      return;
    }
    content.position = location.position;
    var line = location.line;
    if (!IS_UNDEFINED(line)) {
      content.line = line;
    }
    var column = location.column;
    if (!IS_UNDEFINED(column)) {
      content.column = column;
    }
  }
  
  
  /**
   * Serialize property information to the following JSON format for building the
   * array of properties.
   *
   *   {"name":"<property name>",
   *    "attributes":<number>,
   *    "propertyType":<number>,
   *    "ref":<number>}
   *
   * If the attribute for the property is PropertyAttribute.None it is not added.
   * If the propertyType for the property is PropertyType.Normal it is not added.
   * Here are a couple of examples.
   *
   *   {"name":"hello","ref":1}
   *   {"name":"length","attributes":7,"propertyType":3,"ref":2}
   *
   * @param {PropertyMirror} propertyMirror The property to serialize.
   * @returns {Object} Protocol object representing the property.
   */
  JSONProtocolSerializer.prototype.serializeProperty_ = function(propertyMirror) {
    var result = {};
  
    result.name = propertyMirror.name();
    var propertyValue = propertyMirror.value();
    if (this.inlineRefs_() && propertyValue.isValue()) {
      result.value = this.serializeReferenceWithDisplayData_(propertyValue);
    } else {
      if (propertyMirror.attributes() != PropertyAttribute.None) {
        result.attributes = propertyMirror.attributes();
      }
      if (propertyMirror.propertyType() != PropertyType.Normal) {
        result.propertyType = propertyMirror.propertyType();
      }
      result.ref = propertyValue.handle();
    }
    return result;
  };
  
  
  JSONProtocolSerializer.prototype.serializeFrame_ = function(mirror, content) {
    content.index = mirror.index();
    content.receiver = this.serializeReference(mirror.receiver());
    var func = mirror.func();
    content.func = this.serializeReference(func);
    if (func.script()) {
      content.script = this.serializeReference(func.script());
    }
    content.constructCall = mirror.isConstructCall();
    content.atReturn = mirror.isAtReturn();
    if (mirror.isAtReturn()) {
      content.returnValue = this.serializeReference(mirror.returnValue());
    }
    content.debuggerFrame = mirror.isDebuggerFrame();
    var x = new Array(mirror.argumentCount());
    for (var i = 0; i < mirror.argumentCount(); i++) {
      var arg = {};
      var argument_name = mirror.argumentName(i);
      if (argument_name) {
        arg.name = argument_name;
      }
      arg.value = this.serializeReference(mirror.argumentValue(i));
      x[i] = arg;
    }
    content.arguments = x;
    var x = new Array(mirror.localCount());
    for (var i = 0; i < mirror.localCount(); i++) {
      var local = {};
      local.name = mirror.localName(i);
      local.value = this.serializeReference(mirror.localValue(i));
      x[i] = local;
    }
    content.locals = x;
    serializeLocationFields(mirror.sourceLocation(), content);
    var source_line_text = mirror.sourceLineText();
    if (!IS_UNDEFINED(source_line_text)) {
      content.sourceLineText = source_line_text;
    }
  
    content.scopes = [];
    for (var i = 0; i < mirror.scopeCount(); i++) {
      var scope = mirror.scope(i);
      content.scopes.push({
        type: scope.scopeType(),
        index: i
      });
    }
  };
  
  
  JSONProtocolSerializer.prototype.serializeScope_ = function(mirror, content) {
    content.index = mirror.scopeIndex();
    content.frameIndex = mirror.frameIndex();
    content.type = mirror.scopeType();
    content.object = this.inlineRefs_() ?
                     this.serializeValue(mirror.scopeObject()) :
                     this.serializeReference(mirror.scopeObject());
  };
  
  
  /**
   * Convert a number to a protocol value. For all finite numbers the number
   * itself is returned. For non finite numbers NaN, Infinite and
   * -Infinite the string representation "NaN", "Infinite" or "-Infinite"
   * (not including the quotes) is returned.
   *
   * @param {number} value The number value to convert to a protocol value.
   * @returns {number|string} Protocol value.
   */
  function NumberToJSON_(value) {
    if (isNaN(value)) {
      return 'NaN';
    }
    if (!NUMBER_IS_FINITE(value)) {
      if (value > 0) {
        return 'Infinity';
      } else {
        return '-Infinity';
      }
    }
    return value;
  }
  