text: // Copyright 2008 The Closure Library Authors. All Rights Reserved.
  //
  // 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.
  
  /**
   * @fileoverview Protocol Buffer (Message) Descriptor class.
   */
  
  goog.provide('goog.proto2.Descriptor');
  goog.provide('goog.proto2.Metadata');
  
  goog.require('goog.array');
  goog.require('goog.asserts');
  goog.require('goog.object');
  goog.require('goog.string');
  
  
  /**
   * @typedef {{name: (string|undefined),
   *            fullName: (string|undefined),
   *            containingType: (goog.proto2.Message|undefined)}}
   */
  goog.proto2.Metadata;
  
  
  
  /**
   * A class which describes a Protocol Buffer 2 Message.
   *
   * @param {function(new:goog.proto2.Message)} messageType Constructor for
   *      the message class that this descriptor describes.
   * @param {!goog.proto2.Metadata} metadata The metadata about the message that
   *      will be used to construct this descriptor.
   * @param {Array.<!goog.proto2.FieldDescriptor>} fields The fields of the
   *      message described by this descriptor.
   *
   * @constructor
   * @final
   */
  goog.proto2.Descriptor = function(messageType, metadata, fields) {
  
    /**
     * @type {function(new:goog.proto2.Message)}
     * @private
     */
    this.messageType_ = messageType;
  
    /**
     * @type {?string}
     * @private
     */
    this.name_ = metadata.name || null;
  
    /**
     * @type {?string}
     * @private
     */
    this.fullName_ = metadata.fullName || null;
  
    /**
     * @type {goog.proto2.Message|undefined}
     * @private
     */
    this.containingType_ = metadata.containingType;
  
    /**
     * The fields of the message described by this descriptor.
     * @type {!Object.<number, !goog.proto2.FieldDescriptor>}
     * @private
     */
    this.fields_ = {};
  
    for (var i = 0; i < fields.length; i++) {
      var field = fields[i];
      this.fields_[field.getTag()] = field;
    }
  };
  
  
  /**
   * Returns the metadata descriptor representing the definition of a message.
   *
   * @param {function(new:goog.proto2.Message)} messageType Constructor for the
   *     message type to which this metadata applies.
   * @return {!goog.proto2.Descriptor} The new descriptor.
   */
  goog.proto2.Descriptor.getDescriptor = function(messageType) {
    // Descriptors are lazy-created and cached on the constructor.
    // Imitate private property convention to encourage use of public getters.
    return messageType['descriptor_'] ||
        // Create an instance of messageType to reach the "getDescriptor" method.
        // At most one instance will ever be created in this way.
        (messageType['descriptor_'] = (new messageType()).getDescriptor());
  };
  
  
  /**
   * Returns the name of the message, if any.
   *
   * @return {?string} The name.
   */
  goog.proto2.Descriptor.prototype.getName = function() {
    return this.name_;
  };
  
  
  /**
   * Returns the full name of the message, if any.
   *
   * @return {?string} The name.
   */
  goog.proto2.Descriptor.prototype.getFullName = function() {
    return this.fullName_;
  };
  
  
  /**
   * Returns the descriptor of the containing message type or null if none.
   *
   * @return {goog.proto2.Descriptor} The descriptor.
   */
  goog.proto2.Descriptor.prototype.getContainingType = function() {
    if (!this.containingType_) {
      return null;
    }
  
    return this.containingType_.getDescriptor();
  };
  
  
  /**
   * Returns the fields in the message described by this descriptor ordered by
   * tag.
   *
   * @return {!Array.<!goog.proto2.FieldDescriptor>} The array of field
   *     descriptors.
   */
  goog.proto2.Descriptor.prototype.getFields = function() {
    /**
     * @param {!goog.proto2.FieldDescriptor} fieldA First field.
     * @param {!goog.proto2.FieldDescriptor} fieldB Second field.
     * @return {number} Negative if fieldA's tag number is smaller, positive
     *     if greater, zero if the same.
     */
    function tagComparator(fieldA, fieldB) {
      return fieldA.getTag() - fieldB.getTag();
    };
  
    var fields = goog.object.getValues(this.fields_);
    goog.array.sort(fields, tagComparator);
  
    return fields;
  };
  
  
  /**
   * Returns the fields in the message as a key/value map, where the key is
   * the tag number of the field. DO NOT MODIFY THE RETURNED OBJECT. We return
   * the actual, internal, fields map for performance reasons, and changing the
   * map can result in undefined behavior of this library.
   *
   * @return {!Object.<number, !goog.proto2.FieldDescriptor>} The field map.
   */
  goog.proto2.Descriptor.prototype.getFieldsMap = function() {
    return this.fields_;
  };
  
  
  /**
   * Returns the field matching the given name, if any. Note that
   * this method searches over the *original* name of the field,
   * not the camelCase version.
   *
   * @param {string} name The field name for which to search.
   *
   * @return {goog.proto2.FieldDescriptor} The field found, if any.
   */
  goog.proto2.Descriptor.prototype.findFieldByName = function(name) {
    var valueFound = goog.object.findValue(this.fields_,
        function(field, key, obj) {
          return field.getName() == name;
        });
  
    return /** @type {goog.proto2.FieldDescriptor} */ (valueFound) || null;
  };
  
  
  /**
   * Returns the field matching the given tag number, if any.
   *
   * @param {number|string} tag The field tag number for which to search.
   *
   * @return {goog.proto2.FieldDescriptor} The field found, if any.
   */
  goog.proto2.Descriptor.prototype.findFieldByTag = function(tag) {
    goog.asserts.assert(goog.string.isNumeric(tag));
    return this.fields_[parseInt(tag, 10)] || null;
  };
  
  
  /**
   * Creates an instance of the message type that this descriptor
   * describes.
   *
   * @return {!goog.proto2.Message} The instance of the message.
   */
  goog.proto2.Descriptor.prototype.createMessageInstance = function() {
    return new this.messageType_;
  };
  