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1 /*
2  * Copyright 2014 Google Inc. All rights reserved.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef FLATBUFFERS_CODE_GENERATORS_H_
18 #define FLATBUFFERS_CODE_GENERATORS_H_
19 
20 #include <map>
21 #include <sstream>
22 
23 #include "flatbuffers/idl.h"
24 
25 namespace flatbuffers {
26 
27 // Utility class to assist in generating code through use of text templates.
28 //
29 // Example code:
30 //   CodeWriter code("\t");
31 //   code.SetValue("NAME", "Foo");
32 //   code += "void {{NAME}}() { printf("%s", "{{NAME}}"); }";
33 //   code.SetValue("NAME", "Bar");
34 //   code += "void {{NAME}}() { printf("%s", "{{NAME}}"); }";
35 //   std::cout << code.ToString() << std::endl;
36 //
37 // Output:
38 //  void Foo() { printf("%s", "Foo"); }
39 //  void Bar() { printf("%s", "Bar"); }
40 class CodeWriter {
41  public:
42   CodeWriter(std::string pad = std::string())
pad_(pad)43       : pad_(pad), cur_ident_lvl_(0), ignore_ident_(false) {}
44 
45   // Clears the current "written" code.
Clear()46   void Clear() {
47     stream_.str("");
48     stream_.clear();
49   }
50 
51   // Associates a key with a value.  All subsequent calls to operator+=, where
52   // the specified key is contained in {{ and }} delimiters will be replaced by
53   // the given value.
SetValue(const std::string & key,const std::string & value)54   void SetValue(const std::string &key, const std::string &value) {
55     value_map_[key] = value;
56   }
57 
GetValue(const std::string & key)58   std::string GetValue(const std::string &key) const {
59     const auto it = value_map_.find(key);
60     return it == value_map_.end() ? "" : it->second;
61   }
62 
63   // Appends the given text to the generated code as well as a newline
64   // character.  Any text within {{ and }} delimeters is replaced by values
65   // previously stored in the CodeWriter by calling SetValue above.  The newline
66   // will be suppressed if the text ends with the \\ character.
67   void operator+=(std::string text);
68 
69   // Returns the current contents of the CodeWriter as a std::string.
ToString()70   std::string ToString() const { return stream_.str(); }
71 
72   // Increase ident level for writing code
IncrementIdentLevel()73   void IncrementIdentLevel() { cur_ident_lvl_++; }
74   // Decrease ident level for writing code
DecrementIdentLevel()75   void DecrementIdentLevel() {
76     if (cur_ident_lvl_) cur_ident_lvl_--;
77   }
78 
79  private:
80   std::map<std::string, std::string> value_map_;
81   std::stringstream stream_;
82   std::string pad_;
83   int cur_ident_lvl_;
84   bool ignore_ident_;
85 
86   // Add ident padding (tab or space) based on ident level
87   void AppendIdent(std::stringstream &stream);
88 };
89 
90 class BaseGenerator {
91  public:
92   virtual bool generate() = 0;
93 
94   static std::string NamespaceDir(const Parser &parser, const std::string &path,
95                                   const Namespace &ns);
96 
97   std::string GeneratedFileName(const std::string &path,
98                                 const std::string &file_name,
99                                 const IDLOptions &options) const;
100 
101  protected:
BaseGenerator(const Parser & parser,const std::string & path,const std::string & file_name,std::string qualifying_start,std::string qualifying_separator,std::string default_extension)102   BaseGenerator(const Parser &parser, const std::string &path,
103                 const std::string &file_name, std::string qualifying_start,
104                 std::string qualifying_separator, std::string default_extension)
105       : parser_(parser),
106         path_(path),
107         file_name_(file_name),
108         qualifying_start_(qualifying_start),
109         qualifying_separator_(qualifying_separator),
110         default_extension_(default_extension) {}
~BaseGenerator()111   virtual ~BaseGenerator() {}
112 
113   // No copy/assign.
114   BaseGenerator &operator=(const BaseGenerator &);
115   BaseGenerator(const BaseGenerator &);
116 
117   std::string NamespaceDir(const Namespace &ns) const;
118 
119   static const char *FlatBuffersGeneratedWarning();
120 
121   static std::string FullNamespace(const char *separator, const Namespace &ns);
122 
123   static std::string LastNamespacePart(const Namespace &ns);
124 
125   // tracks the current namespace for early exit in WrapInNameSpace
126   // c++, java and csharp returns a different namespace from
127   // the following default (no early exit, always fully qualify),
128   // which works for js and php
CurrentNameSpace()129   virtual const Namespace *CurrentNameSpace() const { return nullptr; }
130 
131   // Ensure that a type is prefixed with its namespace even within
132   // its own namespace to avoid conflict between generated method
133   // names and similarly named classes or structs
134   std::string WrapInNameSpace(const Namespace *ns,
135                               const std::string &name) const;
136 
137   std::string WrapInNameSpace(const Definition &def) const;
138 
139   std::string GetNameSpace(const Definition &def) const;
140 
141   const Parser &parser_;
142   const std::string &path_;
143   const std::string &file_name_;
144   const std::string qualifying_start_;
145   const std::string qualifying_separator_;
146   const std::string default_extension_;
147 };
148 
149 struct CommentConfig {
150   const char *first_line;
151   const char *content_line_prefix;
152   const char *last_line;
153 };
154 
155 extern void GenComment(const std::vector<std::string> &dc,
156                        std::string *code_ptr, const CommentConfig *config,
157                        const char *prefix = "");
158 
159 class FloatConstantGenerator {
160  public:
~FloatConstantGenerator()161   virtual ~FloatConstantGenerator() {}
162   std::string GenFloatConstant(const FieldDef &field) const;
163 
164  private:
165   virtual std::string Value(double v, const std::string &src) const = 0;
166   virtual std::string Inf(double v) const = 0;
167   virtual std::string NaN(double v) const = 0;
168 
169   virtual std::string Value(float v, const std::string &src) const = 0;
170   virtual std::string Inf(float v) const = 0;
171   virtual std::string NaN(float v) const = 0;
172 
173   template<typename T>
174   std::string GenFloatConstantImpl(const FieldDef &field) const;
175 };
176 
177 class SimpleFloatConstantGenerator : public FloatConstantGenerator {
178  public:
179   SimpleFloatConstantGenerator(const char *nan_number,
180                                const char *pos_inf_number,
181                                const char *neg_inf_number);
182 
183  private:
184   std::string Value(double v,
185                     const std::string &src) const FLATBUFFERS_OVERRIDE;
186   std::string Inf(double v) const FLATBUFFERS_OVERRIDE;
187   std::string NaN(double v) const FLATBUFFERS_OVERRIDE;
188 
189   std::string Value(float v, const std::string &src) const FLATBUFFERS_OVERRIDE;
190   std::string Inf(float v) const FLATBUFFERS_OVERRIDE;
191   std::string NaN(float v) const FLATBUFFERS_OVERRIDE;
192 
193   const std::string nan_number_;
194   const std::string pos_inf_number_;
195   const std::string neg_inf_number_;
196 };
197 
198 // C++, C#, Java like generator.
199 class TypedFloatConstantGenerator : public FloatConstantGenerator {
200  public:
201   TypedFloatConstantGenerator(const char *double_prefix,
202                               const char *single_prefix, const char *nan_number,
203                               const char *pos_inf_number,
204                               const char *neg_inf_number = "");
205 
206  private:
207   std::string Value(double v,
208                     const std::string &src) const FLATBUFFERS_OVERRIDE;
209   std::string Inf(double v) const FLATBUFFERS_OVERRIDE;
210 
211   std::string NaN(double v) const FLATBUFFERS_OVERRIDE;
212 
213   std::string Value(float v, const std::string &src) const FLATBUFFERS_OVERRIDE;
214   std::string Inf(float v) const FLATBUFFERS_OVERRIDE;
215   std::string NaN(float v) const FLATBUFFERS_OVERRIDE;
216 
217   std::string MakeNaN(const std::string &prefix) const;
218   std::string MakeInf(bool neg, const std::string &prefix) const;
219 
220   const std::string double_prefix_;
221   const std::string single_prefix_;
222   const std::string nan_number_;
223   const std::string pos_inf_number_;
224   const std::string neg_inf_number_;
225 };
226 
227 }  // namespace flatbuffers
228 
229 #endif  // FLATBUFFERS_CODE_GENERATORS_H_
230