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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 <map>
36 
37 #include <google/protobuf/compiler/cpp/cpp_enum.h>
38 #include <google/protobuf/compiler/cpp/cpp_helpers.h>
39 #include <google/protobuf/io/printer.h>
40 #include <google/protobuf/stubs/strutil.h>
41 
42 namespace google {
43 namespace protobuf {
44 namespace compiler {
45 namespace cpp {
46 
47 namespace {
48 // The GOOGLE_ARRAYSIZE constant is the max enum value plus 1. If the max enum value
49 // is kint32max, GOOGLE_ARRAYSIZE will overflow. In such cases we should omit the
50 // generation of the GOOGLE_ARRAYSIZE constant.
ShouldGenerateArraySize(const EnumDescriptor * descriptor)51 bool ShouldGenerateArraySize(const EnumDescriptor* descriptor) {
52   int32 max_value = descriptor->value(0)->number();
53   for (int i = 0; i < descriptor->value_count(); i++) {
54     if (descriptor->value(i)->number() > max_value) {
55       max_value = descriptor->value(i)->number();
56     }
57   }
58   return max_value != kint32max;
59 }
60 
61 // Returns the number of unique numeric enum values. This is less than
62 // descriptor->value_count() when there are aliased values.
CountUniqueValues(const EnumDescriptor * descriptor)63 int CountUniqueValues(const EnumDescriptor* descriptor) {
64   std::set<int> values;
65   for (int i = 0; i < descriptor->value_count(); ++i) {
66     values.insert(descriptor->value(i)->number());
67   }
68   return values.size();
69 }
70 
71 }  // namespace
72 
EnumGenerator(const EnumDescriptor * descriptor,const std::map<std::string,std::string> & vars,const Options & options)73 EnumGenerator::EnumGenerator(const EnumDescriptor* descriptor,
74                              const std::map<std::string, std::string>& vars,
75                              const Options& options)
76     : descriptor_(descriptor),
77       classname_(ClassName(descriptor, false)),
78       options_(options),
79       generate_array_size_(ShouldGenerateArraySize(descriptor)),
80       variables_(vars) {
81   variables_["classname"] = classname_;
82   variables_["classtype"] = QualifiedClassName(descriptor_, options);
83   variables_["short_name"] = descriptor_->name();
84   variables_["nested_name"] = descriptor_->name();
85   variables_["resolved_name"] = ResolveKeyword(descriptor_->name());
86   variables_["prefix"] =
87       (descriptor_->containing_type() == NULL) ? "" : classname_ + "_";
88 }
89 
~EnumGenerator()90 EnumGenerator::~EnumGenerator() {}
91 
GenerateDefinition(io::Printer * printer)92 void EnumGenerator::GenerateDefinition(io::Printer* printer) {
93   Formatter format(printer, variables_);
94   format("enum ${1$$classname$$}$ : int {\n", descriptor_);
95   format.Indent();
96 
97   const EnumValueDescriptor* min_value = descriptor_->value(0);
98   const EnumValueDescriptor* max_value = descriptor_->value(0);
99 
100   for (int i = 0; i < descriptor_->value_count(); i++) {
101     auto format_value = format;
102     format_value.Set("name", EnumValueName(descriptor_->value(i)));
103     // In C++, an value of -2147483648 gets interpreted as the negative of
104     // 2147483648, and since 2147483648 can't fit in an integer, this produces a
105     // compiler warning.  This works around that issue.
106     format_value.Set("number", Int32ToString(descriptor_->value(i)->number()));
107     format_value.Set(
108         "deprecation",
109         DeprecatedAttribute(options_,
110                             descriptor_->value(i)->options().deprecated()));
111 
112     if (i > 0) format_value(",\n");
113     format_value("${1$$prefix$$name$$}$ $deprecation$= $number$",
114                  descriptor_->value(i));
115 
116     if (descriptor_->value(i)->number() < min_value->number()) {
117       min_value = descriptor_->value(i);
118     }
119     if (descriptor_->value(i)->number() > max_value->number()) {
120       max_value = descriptor_->value(i);
121     }
122   }
123 
124   if (descriptor_->file()->syntax() == FileDescriptor::SYNTAX_PROTO3) {
125     // For new enum semantics: generate min and max sentinel values equal to
126     // INT32_MIN and INT32_MAX
127     if (descriptor_->value_count() > 0) format(",\n");
128     format(
129         "$classname$_$prefix$INT_MIN_SENTINEL_DO_NOT_USE_ = "
130         "std::numeric_limits<$int32$>::min(),\n"
131         "$classname$_$prefix$INT_MAX_SENTINEL_DO_NOT_USE_ = "
132         "std::numeric_limits<$int32$>::max()");
133   }
134 
135   format.Outdent();
136   format("\n};\n");
137 
138   format(
139       "$dllexport_decl $bool $classname$_IsValid(int value);\n"
140       "constexpr $classname$ ${1$$prefix$$short_name$_MIN$}$ = "
141       "$prefix$$2$;\n"
142       "constexpr $classname$ ${1$$prefix$$short_name$_MAX$}$ = "
143       "$prefix$$3$;\n",
144       descriptor_, EnumValueName(min_value), EnumValueName(max_value));
145 
146   if (generate_array_size_) {
147     format(
148         "constexpr int ${1$$prefix$$short_name$_ARRAYSIZE$}$ = "
149         "$prefix$$short_name$_MAX + 1;\n\n",
150         descriptor_);
151   }
152 
153   if (HasDescriptorMethods(descriptor_->file(), options_)) {
154     format(
155         "$dllexport_decl $const ::$proto_ns$::EnumDescriptor* "
156         "$classname$_descriptor();\n");
157   }
158 
159   // The _Name and _Parse functions. The lite implementation is table-based, so
160   // we make sure to keep the tables hidden in the .cc file.
161   if (!HasDescriptorMethods(descriptor_->file(), options_)) {
162     format("const std::string& $classname$_Name($classname$ value);\n");
163   }
164   // The _Name() function accepts the enum type itself but also any integral
165   // type.
166   format(
167       "template<typename T>\n"
168       "inline const std::string& $classname$_Name(T enum_t_value) {\n"
169       "  static_assert(::std::is_same<T, $classname$>::value ||\n"
170       "    ::std::is_integral<T>::value,\n"
171       "    \"Incorrect type passed to function $classname$_Name.\");\n");
172   if (HasDescriptorMethods(descriptor_->file(), options_)) {
173     format(
174         "  return ::$proto_ns$::internal::NameOfEnum(\n"
175         "    $classname$_descriptor(), enum_t_value);\n");
176   } else {
177     format(
178         "  return $classname$_Name(static_cast<$classname$>(enum_t_value));\n");
179   }
180   format("}\n");
181 
182   if (HasDescriptorMethods(descriptor_->file(), options_)) {
183     format(
184         "inline bool $classname$_Parse(\n"
185         "    const std::string& name, $classname$* value) {\n"
186         "  return ::$proto_ns$::internal::ParseNamedEnum<$classname$>(\n"
187         "    $classname$_descriptor(), name, value);\n"
188         "}\n");
189   } else {
190     format(
191         "bool $classname$_Parse(\n"
192         "    const std::string& name, $classname$* value);\n");
193   }
194 }
195 
GenerateGetEnumDescriptorSpecializations(io::Printer * printer)196 void EnumGenerator::GenerateGetEnumDescriptorSpecializations(
197     io::Printer* printer) {
198   Formatter format(printer, variables_);
199   format(
200       "template <> struct is_proto_enum< $classtype$> : ::std::true_type "
201       "{};\n");
202   if (HasDescriptorMethods(descriptor_->file(), options_)) {
203     format(
204         "template <>\n"
205         "inline const EnumDescriptor* GetEnumDescriptor< $classtype$>() {\n"
206         "  return $classtype$_descriptor();\n"
207         "}\n");
208   }
209 }
210 
GenerateSymbolImports(io::Printer * printer) const211 void EnumGenerator::GenerateSymbolImports(io::Printer* printer) const {
212   Formatter format(printer, variables_);
213   format("typedef $classname$ $resolved_name$;\n");
214 
215   for (int j = 0; j < descriptor_->value_count(); j++) {
216     std::string deprecated_attr = DeprecatedAttribute(
217         options_, descriptor_->value(j)->options().deprecated());
218     format(
219         "$1$static constexpr $resolved_name$ ${2$$3$$}$ =\n"
220         "  $classname$_$3$;\n",
221         deprecated_attr, descriptor_->value(j),
222         EnumValueName(descriptor_->value(j)));
223   }
224 
225   format(
226       "static inline bool $nested_name$_IsValid(int value) {\n"
227       "  return $classname$_IsValid(value);\n"
228       "}\n"
229       "static constexpr $resolved_name$ ${1$$nested_name$_MIN$}$ =\n"
230       "  $classname$_$nested_name$_MIN;\n"
231       "static constexpr $resolved_name$ ${1$$nested_name$_MAX$}$ =\n"
232       "  $classname$_$nested_name$_MAX;\n",
233       descriptor_);
234   if (generate_array_size_) {
235     format(
236         "static constexpr int ${1$$nested_name$_ARRAYSIZE$}$ =\n"
237         "  $classname$_$nested_name$_ARRAYSIZE;\n",
238         descriptor_);
239   }
240 
241   if (HasDescriptorMethods(descriptor_->file(), options_)) {
242     format(
243         "static inline const ::$proto_ns$::EnumDescriptor*\n"
244         "$nested_name$_descriptor() {\n"
245         "  return $classname$_descriptor();\n"
246         "}\n");
247   }
248 
249   format(
250       "template<typename T>\n"
251       "static inline const std::string& $nested_name$_Name(T enum_t_value) {\n"
252       "  static_assert(::std::is_same<T, $resolved_name$>::value ||\n"
253       "    ::std::is_integral<T>::value,\n"
254       "    \"Incorrect type passed to function $nested_name$_Name.\");\n"
255       "  return $classname$_Name(enum_t_value);\n"
256       "}\n");
257   format(
258       "static inline bool $nested_name$_Parse(const std::string& name,\n"
259       "    $resolved_name$* value) {\n"
260       "  return $classname$_Parse(name, value);\n"
261       "}\n");
262 }
263 
GenerateMethods(int idx,io::Printer * printer)264 void EnumGenerator::GenerateMethods(int idx, io::Printer* printer) {
265   Formatter format(printer, variables_);
266   if (HasDescriptorMethods(descriptor_->file(), options_)) {
267     format(
268         "const ::$proto_ns$::EnumDescriptor* $classname$_descriptor() {\n"
269         "  ::$proto_ns$::internal::AssignDescriptors(&$desc_table$);\n"
270         "  return $file_level_enum_descriptors$[$1$];\n"
271         "}\n",
272         idx);
273   }
274 
275   format(
276       "bool $classname$_IsValid(int value) {\n"
277       "  switch (value) {\n");
278 
279   // Multiple values may have the same number.  Make sure we only cover
280   // each number once by first constructing a set containing all valid
281   // numbers, then printing a case statement for each element.
282 
283   std::set<int> numbers;
284   for (int j = 0; j < descriptor_->value_count(); j++) {
285     const EnumValueDescriptor* value = descriptor_->value(j);
286     numbers.insert(value->number());
287   }
288 
289   for (std::set<int>::iterator iter = numbers.begin(); iter != numbers.end();
290        ++iter) {
291     format("    case $1$:\n", Int32ToString(*iter));
292   }
293 
294   format(
295       "      return true;\n"
296       "    default:\n"
297       "      return false;\n"
298       "  }\n"
299       "}\n"
300       "\n");
301 
302   if (!HasDescriptorMethods(descriptor_->file(), options_)) {
303     // In lite mode (where descriptors are unavailable), we generate separate
304     // tables for mapping between enum names and numbers. The _entries table
305     // contains the bulk of the data and is sorted by name, while
306     // _entries_by_number is sorted by number and just contains pointers into
307     // _entries. The two tables allow mapping from name to number and number to
308     // name, both in time logarithmic in the number of enum entries. This could
309     // probably be made faster, but for now the tables are intended to be simple
310     // and compact.
311     //
312     // Enums with allow_alias = true support multiple entries with the same
313     // numerical value. In cases where there are multiple names for the same
314     // number, we treat the first name appearing in the .proto file as the
315     // canonical one.
316     std::map<std::string, int> name_to_number;
317     std::map<int, std::string> number_to_canonical_name;
318     for (int i = 0; i < descriptor_->value_count(); i++) {
319       const EnumValueDescriptor* value = descriptor_->value(i);
320       name_to_number.emplace(value->name(), value->number());
321       // The same number may appear with multiple names, so we use emplace() to
322       // let the first name win.
323       number_to_canonical_name.emplace(value->number(), value->name());
324     }
325 
326     format(
327         "static ::$proto_ns$::internal::ExplicitlyConstructed<std::string> "
328         "$classname$_strings[$1$] = {};\n\n",
329         CountUniqueValues(descriptor_));
330 
331     // We concatenate all the names for a given enum into one big string
332     // literal. If instead we store an array of string literals, the linker
333     // seems to put all enum strings for a given .proto file in the same
334     // section, which hinders its ability to strip out unused strings.
335     format("static const char $classname$_names[] =");
336     for (const auto& p : name_to_number) {
337       format("\n  \"$1$\"", p.first);
338     }
339     format(";\n\n");
340 
341     format(
342         "static const ::$proto_ns$::internal::EnumEntry $classname$_entries[] "
343         "= {\n");
344     int i = 0;
345     std::map<int, int> number_to_index;
346     int data_index = 0;
347     for (const auto& p : name_to_number) {
348       format("  { {$classname$_names + $1$, $2$}, $3$ },\n", data_index,
349              p.first.size(), p.second);
350       if (number_to_canonical_name[p.second] == p.first) {
351         number_to_index.emplace(p.second, i);
352       }
353       ++i;
354       data_index += p.first.size();
355     }
356 
357     format(
358         "};\n"
359         "\n"
360         "static const int $classname$_entries_by_number[] = {\n");
361     for (const auto& p : number_to_index) {
362       format("  $1$, // $2$ -> $3$\n", p.second, p.first,
363              number_to_canonical_name[p.first]);
364     }
365     format(
366         "};\n"
367         "\n");
368 
369     format(
370         "const std::string& $classname$_Name(\n"
371         "    $classname$ value) {\n"
372         "  static const bool dummy =\n"
373         "      ::$proto_ns$::internal::InitializeEnumStrings(\n"
374         "          $classname$_entries,\n"
375         "          $classname$_entries_by_number,\n"
376         "          $1$, $classname$_strings);\n"
377         "  (void) dummy;\n"
378         "  int idx = ::$proto_ns$::internal::LookUpEnumName(\n"
379         "      $classname$_entries,\n"
380         "      $classname$_entries_by_number,\n"
381         "      $1$, value);\n"
382         "  return idx == -1 ? ::$proto_ns$::internal::GetEmptyString() :\n"
383         "                     $classname$_strings[idx].get();\n"
384         "}\n",
385         CountUniqueValues(descriptor_));
386     format(
387         "bool $classname$_Parse(\n"
388         "    const std::string& name, $classname$* value) {\n"
389         "  int int_value;\n"
390         "  bool success = ::$proto_ns$::internal::LookUpEnumValue(\n"
391         "      $classname$_entries, $1$, name, &int_value);\n"
392         "  if (success) {\n"
393         "    *value = static_cast<$classname$>(int_value);\n"
394         "  }\n"
395         "  return success;\n"
396         "}\n",
397         descriptor_->value_count());
398   }
399 
400   if (descriptor_->containing_type() != NULL) {
401     std::string parent = ClassName(descriptor_->containing_type(), false);
402     // Before C++17, we must define the static constants which were
403     // declared in the header, to give the linker a place to put them.
404     // But pre-2015 MSVC++ insists that we not.
405     format(
406         "#if (__cplusplus < 201703) && "
407         "(!defined(_MSC_VER) || _MSC_VER >= 1900)\n");
408 
409     for (int i = 0; i < descriptor_->value_count(); i++) {
410       format("constexpr $classname$ $1$::$2$;\n", parent,
411              EnumValueName(descriptor_->value(i)));
412     }
413     format(
414         "constexpr $classname$ $1$::$nested_name$_MIN;\n"
415         "constexpr $classname$ $1$::$nested_name$_MAX;\n",
416         parent);
417     if (generate_array_size_) {
418       format("constexpr int $1$::$nested_name$_ARRAYSIZE;\n", parent);
419     }
420 
421     format(
422         "#endif  // (__cplusplus < 201703) && "
423         "(!defined(_MSC_VER) || _MSC_VER >= 1900)\n");
424   }
425 }
426 
427 }  // namespace cpp
428 }  // namespace compiler
429 }  // namespace protobuf
430 }  // namespace google
431