1#region Copyright notice and license
2// Protocol Buffers - Google's data interchange format
3// Copyright 2008 Google Inc.  All rights reserved.
4// https://developers.google.com/protocol-buffers/
5//
6// Redistribution and use in source and binary forms, with or without
7// modification, are permitted provided that the following conditions are
8// met:
9//
10//     * Redistributions of source code must retain the above copyright
11// notice, this list of conditions and the following disclaimer.
12//     * Redistributions in binary form must reproduce the above
13// copyright notice, this list of conditions and the following disclaimer
14// in the documentation and/or other materials provided with the
15// distribution.
16//     * Neither the name of Google Inc. nor the names of its
17// contributors may be used to endorse or promote products derived from
18// this software without specific prior written permission.
19//
20// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31#endregion
32
33using System.Collections.Generic;
34
35namespace Google.Protobuf.Reflection
36{
37    /// <summary>
38    /// Base class for nearly all descriptors, providing common functionality.
39    /// </summary>
40    public abstract class DescriptorBase : IDescriptor
41    {
42        internal DescriptorBase(FileDescriptor file, string fullName, int index)
43        {
44            File = file;
45            FullName = fullName;
46            Index = index;
47        }
48
49        /// <value>
50        /// The index of this descriptor within its parent descriptor.
51        /// </value>
52        /// <remarks>
53        /// This returns the index of this descriptor within its parent, for
54        /// this descriptor's type. (There can be duplicate values for different
55        /// types, e.g. one enum type with index 0 and one message type with index 0.)
56        /// </remarks>
57        public int Index { get; }
58
59        /// <summary>
60        /// Returns the name of the entity (field, message etc) being described.
61        /// </summary>
62        public abstract string Name { get; }
63
64        /// <summary>
65        /// The fully qualified name of the descriptor's target.
66        /// </summary>
67        public string FullName { get; }
68
69        /// <value>
70        /// The file this descriptor was declared in.
71        /// </value>
72        public FileDescriptor File { get; }
73
74        /// <summary>
75        /// The declaration information about the descriptor, or null if no declaration information
76        /// is available for this descriptor.
77        /// </summary>
78        /// <remarks>
79        /// This information is typically only available for dynamically loaded descriptors,
80        /// for example within a protoc plugin where the full descriptors, including source info,
81        /// are passed to the code by protoc.
82        /// </remarks>
83        public DescriptorDeclaration Declaration => File.GetDeclaration(this);
84
85        /// <summary>
86        /// Retrieves the list of nested descriptors corresponding to the given field number, if any.
87        /// If the field is unknown or not a nested descriptor list, return null to terminate the search.
88        /// The default implementation returns null.
89        /// </summary>
90        internal virtual IReadOnlyList<DescriptorBase> GetNestedDescriptorListForField(int fieldNumber) => null;
91    }
92}