aboutsummaryrefslogtreecommitdiffhomepage
path: root/csharp/src/Google.Protobuf/Reflection/DescriptorPool.cs
blob: 99ca4bf34f1418fc241aa734ba9d75d4fcae4a8d (plain)
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
99
100
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
262
263
264
265
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
368
#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;
            }

            // dependencies contains direct dependencies and any *public* dependencies
            // of those dependencies (transitively)... so we don't need to recurse here.
            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;
            }
        }
    }
}