Revert https://codereview.chromium.org/1291903002 (protobuf roll).

third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs

Index: third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs
diff --git a/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs b/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs
deleted file mode 100644
index 759955e635f86b57146c49ea1681fffa4a020af3..0000000000000000000000000000000000000000
--- a/third_party/protobuf/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs
+++ /dev/null
@@ -1,366 +0,0 @@
-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-// https://developers.google.com/protocol-buffers/
-//
-// 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.
-#endregion
-
-using System;
-using System.Collections.Generic;
-using System.Text;
-using System.Text.RegularExpressions;
-
-namespace Google.Protobuf.Reflection
-{
-    /// <summary>
-    /// Contains lookup tables containing all the descriptors defined in a particular file.
-    /// </summary>
-    internal sealed class DescriptorPool
-    {
-        private readonly IDictionary<string, IDescriptor> descriptorsByName =
-            new Dictionary<string, IDescriptor>();
-
-        private readonly IDictionary<DescriptorIntPair, FieldDescriptor> fieldsByNumber =
-            new Dictionary<DescriptorIntPair, FieldDescriptor>();
-
-        private readonly IDictionary<DescriptorIntPair, EnumValueDescriptor> enumValuesByNumber =
-            new Dictionary<DescriptorIntPair, EnumValueDescriptor>();
-
-        private readonly HashSet<FileDescriptor> dependencies;
-
-        internal DescriptorPool(FileDescriptor[] dependencyFiles)
-        {
-            dependencies = new HashSet<FileDescriptor>();
-            for (int i = 0; i < dependencyFiles.Length; i++)
-            {
-                dependencies.Add(dependencyFiles[i]);
-                ImportPublicDependencies(dependencyFiles[i]);
-            }
-
-            foreach (FileDescriptor dependency in dependencyFiles)
-            {
-                AddPackage(dependency.Package, dependency);
-            }
-        }
-
-        private void ImportPublicDependencies(FileDescriptor file)
-        {
-            foreach (FileDescriptor dependency in file.PublicDependencies)
-            {
-                if (dependencies.Add(dependency))
-                {
-                    ImportPublicDependencies(dependency);
-                }
-            }
-        }
-
-        /// <summary>
-        /// Finds a symbol of the given name within the pool.
-        /// </summary>
-        /// <typeparam name="T">The type of symbol to look for</typeparam>
-        /// <param name="fullName">Fully-qualified name to look up</param>
-        /// <returns>The symbol with the given name and type,
-        /// or null if the symbol doesn't exist or has the wrong type</returns>
-        internal T FindSymbol<T>(string fullName) where T : class
-        {
-            IDescriptor result;
-            descriptorsByName.TryGetValue(fullName, out result);
-            T descriptor = result as T;
-            if (descriptor != null)
-            {
-                return descriptor;
-            }
-
-            foreach (FileDescriptor dependency in dependencies)
-            {
-                dependency.DescriptorPool.descriptorsByName.TryGetValue(fullName, out result);
-                descriptor = result as T;
-                if (descriptor != null)
-                {
-                    return descriptor;
-                }
-            }
-
-            return null;
-        }
-
-        /// <summary>
-        /// Adds a package to the symbol tables. If a package by the same name
-        /// already exists, that is fine, but if some other kind of symbol
-        /// exists under the same name, an exception is thrown. If the package
-        /// has multiple components, this also adds the parent package(s).
-        /// </summary>
-        internal void AddPackage(string fullName, FileDescriptor file)
-        {
-            int dotpos = fullName.LastIndexOf('.');
-            String name;
-            if (dotpos != -1)
-            {
-                AddPackage(fullName.Substring(0, dotpos), file);
-                name = fullName.Substring(dotpos + 1);
-            }
-            else
-            {
-                name = fullName;
-            }
-
-            IDescriptor old;
-            if (descriptorsByName.TryGetValue(fullName, out old))
-            {
-                if (!(old is PackageDescriptor))
-                {
-                    throw new DescriptorValidationException(file,
-                                                            "\"" + name +
-                                                            "\" is already defined (as something other than a " +
-                                                            "package) in file \"" + old.File.Name + "\".");
-                }
-            }
-            descriptorsByName[fullName] = new PackageDescriptor(name, fullName, file);
-        }
-
-        /// <summary>
-        /// Adds a symbol to the symbol table.
-        /// </summary>
-        /// <exception cref="DescriptorValidationException">The symbol already existed
-        /// in the symbol table.</exception>
-        internal void AddSymbol(IDescriptor descriptor)
-        {
-            ValidateSymbolName(descriptor);
-            String fullName = descriptor.FullName;
-
-            IDescriptor old;
-            if (descriptorsByName.TryGetValue(fullName, out old))
-            {
-                int dotPos = fullName.LastIndexOf('.');
-                string message;
-                if (descriptor.File == old.File)
-                {
-                    if (dotPos == -1)
-                    {
-                        message = "\"" + fullName + "\" is already defined.";
-                    }
-                    else
-                    {
-                        message = "\"" + fullName.Substring(dotPos + 1) + "\" is already defined in \"" +
-                                  fullName.Substring(0, dotPos) + "\".";
-                    }
-                }
-                else
-                {
-                    message = "\"" + fullName + "\" is already defined in file \"" + old.File.Name + "\".";
-                }
-                throw new DescriptorValidationException(descriptor, message);
-            }
-            descriptorsByName[fullName] = descriptor;
-        }
-
-        private static readonly Regex ValidationRegex = new Regex("^[_A-Za-z][_A-Za-z0-9]*$",
-                                                                  FrameworkPortability.CompiledRegexWhereAvailable);
-
-        /// <summary>
-        /// Verifies that the descriptor's name is valid (i.e. it contains
-        /// only letters, digits and underscores, and does not start with a digit).
-        /// </summary>
-        /// <param name="descriptor"></param>
-        private static void ValidateSymbolName(IDescriptor descriptor)
-        {
-            if (descriptor.Name == "")
-            {
-                throw new DescriptorValidationException(descriptor, "Missing name.");
-            }
-            if (!ValidationRegex.IsMatch(descriptor.Name))
-            {
-                throw new DescriptorValidationException(descriptor,
-                                                        "\"" + descriptor.Name + "\" is not a valid identifier.");
-            }
-        }
-
-        /// <summary>
-        /// Returns the field with the given number in the given descriptor,
-        /// or null if it can't be found.
-        /// </summary>
-        internal FieldDescriptor FindFieldByNumber(MessageDescriptor messageDescriptor, int number)
-        {
-            FieldDescriptor ret;
-            fieldsByNumber.TryGetValue(new DescriptorIntPair(messageDescriptor, number), out ret);
-            return ret;
-        }
-
-        internal EnumValueDescriptor FindEnumValueByNumber(EnumDescriptor enumDescriptor, int number)
-        {
-            EnumValueDescriptor ret;
-            enumValuesByNumber.TryGetValue(new DescriptorIntPair(enumDescriptor, number), out ret);
-            return ret;
-        }
-
-        /// <summary>
-        /// Adds a field to the fieldsByNumber table.
-        /// </summary>
-        /// <exception cref="DescriptorValidationException">A field with the same
-        /// containing type and number already exists.</exception>
-        internal void AddFieldByNumber(FieldDescriptor field)
-        {
-            DescriptorIntPair key = new DescriptorIntPair(field.ContainingType, field.FieldNumber);
-            FieldDescriptor old;
-            if (fieldsByNumber.TryGetValue(key, out old))
-            {
-                throw new DescriptorValidationException(field, "Field number " + field.FieldNumber +
-                                                               "has already been used in \"" +
-                                                               field.ContainingType.FullName +
-                                                               "\" by field \"" + old.Name + "\".");
-            }
-            fieldsByNumber[key] = field;
-        }
-
-        /// <summary>
-        /// Adds an enum value to the enumValuesByNumber table. If an enum value
-        /// with the same type and number already exists, this method does nothing.
-        /// (This is allowed; the first value defined with the number takes precedence.)
-        /// </summary>
-        internal void AddEnumValueByNumber(EnumValueDescriptor enumValue)
-        {
-            DescriptorIntPair key = new DescriptorIntPair(enumValue.EnumDescriptor, enumValue.Number);
-            if (!enumValuesByNumber.ContainsKey(key))
-            {
-                enumValuesByNumber[key] = enumValue;
-            }
-        }
-
-        /// <summary>
-        /// Looks up a descriptor by name, relative to some other descriptor.
-        /// The name may be fully-qualified (with a leading '.'), partially-qualified,
-        /// or unqualified. C++-like name lookup semantics are used to search for the
-        /// matching descriptor.
-        /// </summary>
-        /// <remarks>
-        /// This isn't heavily optimized, but it's only used during cross linking anyway.
-        /// If it starts being used more widely, we should look at performance more carefully.
-        /// </remarks>
-        internal IDescriptor LookupSymbol(string name, IDescriptor relativeTo)
-        {
-            IDescriptor result;
-            if (name.StartsWith("."))
-            {
-                // Fully-qualified name.
-                result = FindSymbol<IDescriptor>(name.Substring(1));
-            }
-            else
-            {
-                // If "name" is a compound identifier, we want to search for the
-                // first component of it, then search within it for the rest.
-                int firstPartLength = name.IndexOf('.');
-                string firstPart = firstPartLength == -1 ? name : name.Substring(0, firstPartLength);
-
-                // We will search each parent scope of "relativeTo" looking for the
-                // symbol.
-                StringBuilder scopeToTry = new StringBuilder(relativeTo.FullName);
-
-                while (true)
-                {
-                    // Chop off the last component of the scope.
-
-                    int dotpos = scopeToTry.ToString().LastIndexOf(".");
-                    if (dotpos == -1)
-                    {
-                        result = FindSymbol<IDescriptor>(name);
-                        break;
-                    }
-                    else
-                    {
-                        scopeToTry.Length = dotpos + 1;
-
-                        // Append firstPart and try to find.
-                        scopeToTry.Append(firstPart);
-                        result = FindSymbol<IDescriptor>(scopeToTry.ToString());
-
-                        if (result != null)
-                        {
-                            if (firstPartLength != -1)
-                            {
-                                // We only found the first part of the symbol.  Now look for
-                                // the whole thing.  If this fails, we *don't* want to keep
-                                // searching parent scopes.
-                                scopeToTry.Length = dotpos + 1;
-                                scopeToTry.Append(name);
-                                result = FindSymbol<IDescriptor>(scopeToTry.ToString());
-                            }
-                            break;
-                        }
-
-                        // Not found.  Remove the name so we can try again.
-                        scopeToTry.Length = dotpos;
-                    }
-                }
-            }
-
-            if (result == null)
-            {
-                throw new DescriptorValidationException(relativeTo, "\"" + name + "\" is not defined.");
-            }
-            else
-            {
-                return result;
-            }
-        }
-
-        /// <summary>
-        /// Struct used to hold the keys for the fieldByNumber table.
-        /// </summary>
-        private struct DescriptorIntPair : IEquatable<DescriptorIntPair>
-        {
-            private readonly int number;
-            private readonly IDescriptor descriptor;
-
-            internal DescriptorIntPair(IDescriptor descriptor, int number)
-            {
-                this.number = number;
-                this.descriptor = descriptor;
-            }
-
-            public bool Equals(DescriptorIntPair other)
-            {
-                return descriptor == other.descriptor
-                       && number == other.number;
-            }
-
-            public override bool Equals(object obj)
-            {
-                if (obj is DescriptorIntPair)
-                {
-                    return Equals((DescriptorIntPair) obj);
-                }
-                return false;
-            }
-
-            public override int GetHashCode()
-            {
-                return descriptor.GetHashCode()*((1 << 16) - 1) + number;
-            }
-        }
-    }
-}