DescriptorPool.cs 14.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98
#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;
            }

99 100
            // dependencies contains direct dependencies and any *public* dependencies
            // of those dependencies (transitively)... so we don't need to recurse here.
101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261
            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>
Jon Skeet's avatar
Jon Skeet committed
262 263 264 265
        /// <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>
266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367
        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;
            }
        }
    }
368
}