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1 // Protocol Buffers - Google's data interchange format
2 // Copyright 2008 Google Inc.  All rights reserved.
3 // https://developers.google.com/protocol-buffers/
4 //
5 // Redistribution and use in source and binary forms, with or without
6 // modification, are permitted provided that the following conditions are
7 // met:
8 //
9 //     * Redistributions of source code must retain the above copyright
10 // notice, this list of conditions and the following disclaimer.
11 //     * Redistributions in binary form must reproduce the above
12 // copyright notice, this list of conditions and the following disclaimer
13 // in the documentation and/or other materials provided with the
14 // distribution.
15 //     * Neither the name of Google Inc. nor the names of its
16 // contributors may be used to endorse or promote products derived from
17 // this software without specific prior written permission.
18 //
19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 
31 // Author: kenton@google.com (Kenton Varda)
32 //  Based on original Protocol Buffers design by
33 //  Sanjay Ghemawat, Jeff Dean, and others.
34 
35 #include <google/protobuf/compiler/cpp/cpp_enum.h>
36 
37 #include <cstdint>
38 #include <limits>
39 #include <map>
40 
41 #include <google/protobuf/io/printer.h>
42 #include <google/protobuf/stubs/strutil.h>
43 #include <google/protobuf/compiler/cpp/cpp_helpers.h>
44 #include <google/protobuf/compiler/cpp/cpp_names.h>
45 
46 namespace google {
47 namespace protobuf {
48 namespace compiler {
49 namespace cpp {
50 
51 namespace {
52 // The GOOGLE_ARRAYSIZE constant is the max enum value plus 1. If the max enum value
53 // is kint32max, GOOGLE_ARRAYSIZE will overflow. In such cases we should omit the
54 // generation of the GOOGLE_ARRAYSIZE constant.
ShouldGenerateArraySize(const EnumDescriptor * descriptor)55 bool ShouldGenerateArraySize(const EnumDescriptor* descriptor) {
56   int32_t max_value = descriptor->value(0)->number();
57   for (int i = 0; i < descriptor->value_count(); i++) {
58     if (descriptor->value(i)->number() > max_value) {
59       max_value = descriptor->value(i)->number();
60     }
61   }
62   return max_value != std::numeric_limits<int32_t>::max();
63 }
64 
65 // Returns the number of unique numeric enum values. This is less than
66 // descriptor->value_count() when there are aliased values.
CountUniqueValues(const EnumDescriptor * descriptor)67 int CountUniqueValues(const EnumDescriptor* descriptor) {
68   std::set<int> values;
69   for (int i = 0; i < descriptor->value_count(); ++i) {
70     values.insert(descriptor->value(i)->number());
71   }
72   return values.size();
73 }
74 
75 }  // namespace
76 
EnumGenerator(const EnumDescriptor * descriptor,const std::map<std::string,std::string> & vars,const Options & options)77 EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor,
78                              const std::map<std::string, std::string>& vars,
79                              const Options& options)
80     : descriptor_(descriptor),
81       classname_(ClassName(descriptor, false)),
82       options_(options),
83       generate_array_size_(ShouldGenerateArraySize(descriptor)),
84       variables_(vars) {
85   variables_["classname"] = classname_;
86   variables_["classtype"] = QualifiedClassName(descriptor_, options);
87   variables_["short_name"] = descriptor_->name();
88   variables_["nested_name"] = descriptor_->name();
89   variables_["resolved_name"] = ResolveKeyword(descriptor_->name());
90   variables_["prefix"] =
91       (descriptor_->containing_type() == nullptr) ? "" : classname_ + "_";
92 }
93 
~EnumGenerator()94 EnumGenerator::~EnumGenerator() {}
95 
GenerateDefinition(io::Printer * printer)96 void EnumGenerator::GenerateDefinition(io::Printer* printer) {
97   Formatter format(printer, variables_);
98   format("enum ${1$$classname$$}$ : int {\n", descriptor_);
99   format.Indent();
100 
101   const EnumValueDescriptor* min_value = descriptor_->value(0);
102   const EnumValueDescriptor* max_value = descriptor_->value(0);
103 
104   for (int i = 0; i < descriptor_->value_count(); i++) {
105     auto format_value = format;
106     format_value.Set("name", EnumValueName(descriptor_->value(i)));
107     // In C++, an value of -2147483648 gets interpreted as the negative of
108     // 2147483648, and since 2147483648 can't fit in an integer, this produces a
109     // compiler warning.  This works around that issue.
110     format_value.Set("number", Int32ToString(descriptor_->value(i)->number()));
111     format_value.Set("deprecation",
112                      DeprecatedAttribute(options_, descriptor_->value(i)));
113 
114     if (i > 0) format_value(",\n");
115     format_value("${1$$prefix$$name$$}$ $deprecation$= $number$",
116                  descriptor_->value(i));
117 
118     if (descriptor_->value(i)->number() < min_value->number()) {
119       min_value = descriptor_->value(i);
120     }
121     if (descriptor_->value(i)->number() > max_value->number()) {
122       max_value = descriptor_->value(i);
123     }
124   }
125 
126   if (descriptor_->file()->syntax() == FileDescriptor::SYNTAX_PROTO3) {
127     // For new enum semantics: generate min and max sentinel values equal to
128     // INT32_MIN and INT32_MAX
129     if (descriptor_->value_count() > 0) format(",\n");
130     format(
131         "$classname$_$prefix$INT_MIN_SENTINEL_DO_NOT_USE_ = "
132         "std::numeric_limits<$int32$>::min(),\n"
133         "$classname$_$prefix$INT_MAX_SENTINEL_DO_NOT_USE_ = "
134         "std::numeric_limits<$int32$>::max()");
135   }
136 
137   format.Outdent();
138   format("\n};\n");
139 
140   format(
141       "$dllexport_decl $bool $classname$_IsValid(int value);\n"
142       "constexpr $classname$ ${1$$prefix$$short_name$_MIN$}$ = "
143       "$prefix$$2$;\n"
144       "constexpr $classname$ ${1$$prefix$$short_name$_MAX$}$ = "
145       "$prefix$$3$;\n",
146       descriptor_, EnumValueName(min_value), EnumValueName(max_value));
147 
148   if (generate_array_size_) {
149     format(
150         "constexpr int ${1$$prefix$$short_name$_ARRAYSIZE$}$ = "
151         "$prefix$$short_name$_MAX + 1;\n\n",
152         descriptor_);
153   }
154 
155   if (HasDescriptorMethods(descriptor_->file(), options_)) {
156     format(
157         "$dllexport_decl $const ::$proto_ns$::EnumDescriptor* "
158         "$classname$_descriptor();\n");
159   }
160 
161   // The _Name and _Parse functions. The lite implementation is table-based, so
162   // we make sure to keep the tables hidden in the .cc file.
163   if (!HasDescriptorMethods(descriptor_->file(), options_)) {
164     format("const std::string& $classname$_Name($classname$ value);\n");
165   }
166   // The _Name() function accepts the enum type itself but also any integral
167   // type.
168   format(
169       "template<typename T>\n"
170       "inline const std::string& $classname$_Name(T enum_t_value) {\n"
171       "  static_assert(::std::is_same<T, $classname$>::value ||\n"
172       "    ::std::is_integral<T>::value,\n"
173       "    \"Incorrect type passed to function $classname$_Name.\");\n");
174   if (HasDescriptorMethods(descriptor_->file(), options_)) {
175     format(
176         "  return ::$proto_ns$::internal::NameOfEnum(\n"
177         "    $classname$_descriptor(), enum_t_value);\n");
178   } else {
179     format(
180         "  return $classname$_Name(static_cast<$classname$>(enum_t_value));\n");
181   }
182   format("}\n");
183 
184   if (HasDescriptorMethods(descriptor_->file(), options_)) {
185     format(
186         "inline bool $classname$_Parse(\n"
187         "    ::PROTOBUF_NAMESPACE_ID::ConstStringParam name, $classname$* "
188         "value) "
189         "{\n"
190         "  return ::$proto_ns$::internal::ParseNamedEnum<$classname$>(\n"
191         "    $classname$_descriptor(), name, value);\n"
192         "}\n");
193   } else {
194     format(
195         "bool $classname$_Parse(\n"
196         "    ::PROTOBUF_NAMESPACE_ID::ConstStringParam name, $classname$* "
197         "value);\n");
198   }
199 }
200 
GenerateGetEnumDescriptorSpecializations(io::Printer * printer)201 void EnumGenerator::GenerateGetEnumDescriptorSpecializations(
202     io::Printer* printer) {
203   Formatter format(printer, variables_);
204   format(
205       "template <> struct is_proto_enum< $classtype$> : ::std::true_type "
206       "{};\n");
207   if (HasDescriptorMethods(descriptor_->file(), options_)) {
208     format(
209         "template <>\n"
210         "inline const EnumDescriptor* GetEnumDescriptor< $classtype$>() {\n"
211         "  return $classtype$_descriptor();\n"
212         "}\n");
213   }
214 }
215 
GenerateSymbolImports(io::Printer * printer) const216 void EnumGenerator::GenerateSymbolImports(io::Printer* printer) const {
217   Formatter format(printer, variables_);
218   format("typedef $classname$ $resolved_name$;\n");
219 
220   for (int j = 0; j < descriptor_->value_count(); j++) {
221     std::string deprecated_attr =
222         DeprecatedAttribute(options_, descriptor_->value(j));
223     format(
224         "$1$static constexpr $resolved_name$ ${2$$3$$}$ =\n"
225         "  $classname$_$3$;\n",
226         deprecated_attr, descriptor_->value(j),
227         EnumValueName(descriptor_->value(j)));
228   }
229 
230   format(
231       "static inline bool $nested_name$_IsValid(int value) {\n"
232       "  return $classname$_IsValid(value);\n"
233       "}\n"
234       "static constexpr $resolved_name$ ${1$$nested_name$_MIN$}$ =\n"
235       "  $classname$_$nested_name$_MIN;\n"
236       "static constexpr $resolved_name$ ${1$$nested_name$_MAX$}$ =\n"
237       "  $classname$_$nested_name$_MAX;\n",
238       descriptor_);
239   if (generate_array_size_) {
240     format(
241         "static constexpr int ${1$$nested_name$_ARRAYSIZE$}$ =\n"
242         "  $classname$_$nested_name$_ARRAYSIZE;\n",
243         descriptor_);
244   }
245 
246   if (HasDescriptorMethods(descriptor_->file(), options_)) {
247     format(
248         "static inline const ::$proto_ns$::EnumDescriptor*\n"
249         "$nested_name$_descriptor() {\n"
250         "  return $classname$_descriptor();\n"
251         "}\n");
252   }
253 
254   format(
255       "template<typename T>\n"
256       "static inline const std::string& $nested_name$_Name(T enum_t_value) {\n"
257       "  static_assert(::std::is_same<T, $resolved_name$>::value ||\n"
258       "    ::std::is_integral<T>::value,\n"
259       "    \"Incorrect type passed to function $nested_name$_Name.\");\n"
260       "  return $classname$_Name(enum_t_value);\n"
261       "}\n");
262   format(
263       "static inline bool "
264       "$nested_name$_Parse(::PROTOBUF_NAMESPACE_ID::ConstStringParam name,\n"
265       "    $resolved_name$* value) {\n"
266       "  return $classname$_Parse(name, value);\n"
267       "}\n");
268 }
269 
GenerateMethods(int idx,io::Printer * printer)270 void EnumGenerator::GenerateMethods(int idx, io::Printer* printer) {
271   Formatter format(printer, variables_);
272   if (HasDescriptorMethods(descriptor_->file(), options_)) {
273     format(
274         "const ::$proto_ns$::EnumDescriptor* $classname$_descriptor() {\n"
275         "  ::$proto_ns$::internal::AssignDescriptors(&$desc_table$);\n"
276         "  return $file_level_enum_descriptors$[$1$];\n"
277         "}\n",
278         idx);
279   }
280 
281   format(
282       "bool $classname$_IsValid(int value) {\n"
283       "  switch (value) {\n");
284 
285   // Multiple values may have the same number.  Make sure we only cover
286   // each number once by first constructing a set containing all valid
287   // numbers, then printing a case statement for each element.
288 
289   std::set<int> numbers;
290   for (int j = 0; j < descriptor_->value_count(); j++) {
291     const EnumValueDescriptor* value = descriptor_->value(j);
292     numbers.insert(value->number());
293   }
294 
295   for (std::set<int>::iterator iter = numbers.begin(); iter != numbers.end();
296        ++iter) {
297     format("    case $1$:\n", Int32ToString(*iter));
298   }
299 
300   format(
301       "      return true;\n"
302       "    default:\n"
303       "      return false;\n"
304       "  }\n"
305       "}\n"
306       "\n");
307 
308   if (!HasDescriptorMethods(descriptor_->file(), options_)) {
309     // In lite mode (where descriptors are unavailable), we generate separate
310     // tables for mapping between enum names and numbers. The _entries table
311     // contains the bulk of the data and is sorted by name, while
312     // _entries_by_number is sorted by number and just contains pointers into
313     // _entries. The two tables allow mapping from name to number and number to
314     // name, both in time logarithmic in the number of enum entries. This could
315     // probably be made faster, but for now the tables are intended to be simple
316     // and compact.
317     //
318     // Enums with allow_alias = true support multiple entries with the same
319     // numerical value. In cases where there are multiple names for the same
320     // number, we treat the first name appearing in the .proto file as the
321     // canonical one.
322     std::map<std::string, int> name_to_number;
323     std::map<int, std::string> number_to_canonical_name;
324     for (int i = 0; i < descriptor_->value_count(); i++) {
325       const EnumValueDescriptor* value = descriptor_->value(i);
326       name_to_number.emplace(value->name(), value->number());
327       // The same number may appear with multiple names, so we use emplace() to
328       // let the first name win.
329       number_to_canonical_name.emplace(value->number(), value->name());
330     }
331 
332     format(
333         "static ::$proto_ns$::internal::ExplicitlyConstructed<std::string> "
334         "$classname$_strings[$1$] = {};\n\n",
335         CountUniqueValues(descriptor_));
336 
337     // We concatenate all the names for a given enum into one big string
338     // literal. If instead we store an array of string literals, the linker
339     // seems to put all enum strings for a given .proto file in the same
340     // section, which hinders its ability to strip out unused strings.
341     format("static const char $classname$_names[] =");
342     for (const auto& p : name_to_number) {
343       format("\n  \"$1$\"", p.first);
344     }
345     format(";\n\n");
346 
347     format(
348         "static const ::$proto_ns$::internal::EnumEntry $classname$_entries[] "
349         "= {\n");
350     int i = 0;
351     std::map<int, int> number_to_index;
352     int data_index = 0;
353     for (const auto& p : name_to_number) {
354       format("  { {$classname$_names + $1$, $2$}, $3$ },\n", data_index,
355              p.first.size(), p.second);
356       if (number_to_canonical_name[p.second] == p.first) {
357         number_to_index.emplace(p.second, i);
358       }
359       ++i;
360       data_index += p.first.size();
361     }
362 
363     format(
364         "};\n"
365         "\n"
366         "static const int $classname$_entries_by_number[] = {\n");
367     for (const auto& p : number_to_index) {
368       format("  $1$, // $2$ -> $3$\n", p.second, p.first,
369              number_to_canonical_name[p.first]);
370     }
371     format(
372         "};\n"
373         "\n");
374 
375     format(
376         "const std::string& $classname$_Name(\n"
377         "    $classname$ value) {\n"
378         "  static const bool dummy =\n"
379         "      ::$proto_ns$::internal::InitializeEnumStrings(\n"
380         "          $classname$_entries,\n"
381         "          $classname$_entries_by_number,\n"
382         "          $1$, $classname$_strings);\n"
383         "  (void) dummy;\n"
384         "  int idx = ::$proto_ns$::internal::LookUpEnumName(\n"
385         "      $classname$_entries,\n"
386         "      $classname$_entries_by_number,\n"
387         "      $1$, value);\n"
388         "  return idx == -1 ? ::$proto_ns$::internal::GetEmptyString() :\n"
389         "                     $classname$_strings[idx].get();\n"
390         "}\n",
391         CountUniqueValues(descriptor_));
392     format(
393         "bool $classname$_Parse(\n"
394         "    ::PROTOBUF_NAMESPACE_ID::ConstStringParam name, $classname$* "
395         "value) "
396         "{\n"
397         "  int int_value;\n"
398         "  bool success = ::$proto_ns$::internal::LookUpEnumValue(\n"
399         "      $classname$_entries, $1$, name, &int_value);\n"
400         "  if (success) {\n"
401         "    *value = static_cast<$classname$>(int_value);\n"
402         "  }\n"
403         "  return success;\n"
404         "}\n",
405         descriptor_->value_count());
406   }
407 
408   if (descriptor_->containing_type() != nullptr) {
409     std::string parent = ClassName(descriptor_->containing_type(), false);
410     // Before C++17, we must define the static constants which were
411     // declared in the header, to give the linker a place to put them.
412     // But MSVC++ pre-2015 and post-2017 (version 15.5+) insists that we not.
413     format(
414         "#if (__cplusplus < 201703) && "
415         "(!defined(_MSC_VER) || (_MSC_VER >= 1900 && _MSC_VER < 1912))\n");
416 
417     for (int i = 0; i < descriptor_->value_count(); i++) {
418       format("constexpr $classname$ $1$::$2$;\n", parent,
419              EnumValueName(descriptor_->value(i)));
420     }
421     format(
422         "constexpr $classname$ $1$::$nested_name$_MIN;\n"
423         "constexpr $classname$ $1$::$nested_name$_MAX;\n",
424         parent);
425     if (generate_array_size_) {
426       format("constexpr int $1$::$nested_name$_ARRAYSIZE;\n", parent);
427     }
428 
429     format(
430         "#endif  // (__cplusplus < 201703) && "
431         "(!defined(_MSC_VER) || (_MSC_VER >= 1900 && _MSC_VER < 1912))\n");
432   }
433 }
434 
435 }  // namespace cpp
436 }  // namespace compiler
437 }  // namespace protobuf
438 }  // namespace google
439