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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 #include <iostream>
18 #include "flatbuffers/code_generators.h"
19 #include "flatbuffers/idl.h"
20 #include "flatbuffers/util.h"
21 
22 namespace flatbuffers {
23 
GeneratedFileName(const std::string & path,const std::string & file_name)24 static std::string GeneratedFileName(const std::string &path,
25                                      const std::string &file_name) {
26   return path + file_name + ".schema.json";
27 }
28 
29 namespace jsons {
30 
GenNativeType(BaseType type)31 std::string GenNativeType(BaseType type) {
32   switch (type) {
33     case BASE_TYPE_BOOL: return "boolean";
34     case BASE_TYPE_CHAR:
35     case BASE_TYPE_UCHAR:
36     case BASE_TYPE_SHORT:
37     case BASE_TYPE_USHORT:
38     case BASE_TYPE_INT:
39     case BASE_TYPE_UINT:
40     case BASE_TYPE_LONG:
41     case BASE_TYPE_ULONG:
42     case BASE_TYPE_FLOAT:
43     case BASE_TYPE_DOUBLE: return "number";
44     case BASE_TYPE_STRING: return "string";
45     default: return "";
46   }
47 }
48 
GenFullName(const T * enum_def)49 template<class T> std::string GenFullName(const T *enum_def) {
50   std::string full_name;
51   const auto &name_spaces = enum_def->defined_namespace->components;
52   for (auto ns = name_spaces.cbegin(); ns != name_spaces.cend(); ++ns) {
53     full_name.append(*ns + "_");
54   }
55   full_name.append(enum_def->name);
56   return full_name;
57 }
58 
GenTypeRef(const T * enum_def)59 template<class T> std::string GenTypeRef(const T *enum_def) {
60   return "\"$ref\" : \"#/definitions/" + GenFullName(enum_def) + "\"";
61 }
62 
GenType(const std::string & name)63 std::string GenType(const std::string &name) {
64   return "\"type\" : \"" + name + "\"";
65 }
66 
GenType(const Type & type)67 std::string GenType(const Type &type) {
68   if (type.enum_def != nullptr && !type.enum_def->is_union) {
69     // it is a reference to an enum type
70     return GenTypeRef(type.enum_def);
71   }
72   switch (type.base_type) {
73     case BASE_TYPE_VECTOR: {
74       std::string typeline;
75       typeline.append("\"type\" : \"array\", \"items\" : { ");
76       if (type.element == BASE_TYPE_STRUCT) {
77         typeline.append(GenTypeRef(type.struct_def));
78       } else {
79         typeline.append(GenType(GenNativeType(type.element)));
80       }
81       typeline.append(" }");
82       return typeline;
83     }
84     case BASE_TYPE_STRUCT: {
85       return GenTypeRef(type.struct_def);
86     }
87     case BASE_TYPE_UNION: {
88       std::string union_type_string("\"anyOf\": [");
89       const auto &union_types = type.enum_def->vals.vec;
90       for (auto ut = union_types.cbegin(); ut < union_types.cend(); ++ut) {
91         auto &union_type = *ut;
92         if (union_type->union_type.base_type == BASE_TYPE_NONE) { continue; }
93         if (union_type->union_type.base_type == BASE_TYPE_STRUCT) {
94           union_type_string.append(
95               "{ " + GenTypeRef(union_type->union_type.struct_def) + " }");
96         }
97         if (union_type != *type.enum_def->vals.vec.rbegin()) {
98           union_type_string.append(",");
99         }
100       }
101       union_type_string.append("]");
102       return union_type_string;
103     }
104     case BASE_TYPE_UTYPE: return GenTypeRef(type.enum_def);
105     default: return GenType(GenNativeType(type.base_type));
106   }
107 }
108 
109 class JsonSchemaGenerator : public BaseGenerator {
110  private:
111   CodeWriter code_;
112 
113  public:
JsonSchemaGenerator(const Parser & parser,const std::string & path,const std::string & file_name)114   JsonSchemaGenerator(const Parser &parser, const std::string &path,
115                       const std::string &file_name)
116       : BaseGenerator(parser, path, file_name, "", "") {}
117 
JsonSchemaGenerator(const BaseGenerator & base_generator)118   explicit JsonSchemaGenerator(const BaseGenerator &base_generator)
119       : BaseGenerator(base_generator) {}
120 
generate()121   bool generate() {
122     code_.Clear();
123     code_ += "{";
124     code_ += "  \"$schema\": \"http://json-schema.org/draft-04/schema#\",";
125     code_ += "  \"definitions\": {";
126     for (auto e = parser_.enums_.vec.cbegin(); e != parser_.enums_.vec.cend();
127          ++e) {
128       code_ += "    \"" + GenFullName(*e) + "\" : {";
129       code_ += "      " + GenType("string") + ",";
130       std::string enumdef("      \"enum\": [");
131       for (auto enum_value = (*e)->vals.vec.begin();
132            enum_value != (*e)->vals.vec.end(); ++enum_value) {
133         enumdef.append("\"" + (*enum_value)->name + "\"");
134         if (*enum_value != (*e)->vals.vec.back()) { enumdef.append(", "); }
135       }
136       enumdef.append("]");
137       code_ += enumdef;
138       code_ += "    },";  // close type
139     }
140     for (auto s = parser_.structs_.vec.cbegin();
141          s != parser_.structs_.vec.cend(); ++s) {
142       const auto &structure = *s;
143       code_ += "    \"" + GenFullName(structure) + "\" : {";
144       code_ += "      " + GenType("object") + ",";
145       std::string comment;
146       const auto &comment_lines = structure->doc_comment;
147       for (auto comment_line = comment_lines.cbegin();
148            comment_line != comment_lines.cend(); ++comment_line) {
149         comment.append(*comment_line);
150       }
151       if (comment.size() > 0) {
152         code_ += "      \"description\" : \"" + comment + "\",";
153       }
154       code_ += "      \"properties\" : {";
155 
156       const auto &properties = structure->fields.vec;
157       for (auto prop = properties.cbegin(); prop != properties.cend(); ++prop) {
158         const auto &property = *prop;
159         std::string typeLine("        \"" + property->name + "\" : { " +
160                              GenType(property->value.type) + " }");
161         if (property != properties.back()) { typeLine.append(","); }
162         code_ += typeLine;
163       }
164       code_ += "      },";  // close properties
165 
166       std::vector<FieldDef *> requiredProperties;
167       std::copy_if(properties.begin(), properties.end(),
168                    back_inserter(requiredProperties),
169                    [](FieldDef const *prop) { return prop->required; });
170       if (requiredProperties.size() > 0) {
171         std::string required_string("      \"required\" : [");
172         for (auto req_prop = requiredProperties.cbegin();
173              req_prop != requiredProperties.cend(); ++req_prop) {
174           required_string.append("\"" + (*req_prop)->name + "\"");
175           if (*req_prop != requiredProperties.back()) {
176             required_string.append(", ");
177           }
178         }
179         required_string.append("],");
180         code_ += required_string;
181       }
182       code_ += "      \"additionalProperties\" : false";
183       std::string closeType("    }");
184       if (*s != parser_.structs_.vec.back()) { closeType.append(","); }
185       code_ += closeType;  // close type
186     }
187     code_ += "  },";  // close definitions
188 
189     // mark root type
190     code_ += "  \"$ref\" : \"#/definitions/" +
191              GenFullName(parser_.root_struct_def_) + "\"";
192 
193     code_ += "}";  // close schema root
194     const std::string file_path = GeneratedFileName(path_, file_name_);
195     const std::string final_code = code_.ToString();
196     return SaveFile(file_path.c_str(), final_code, false);
197   }
198 };
199 }  // namespace jsons
200 
GenerateJsonSchema(const Parser & parser,const std::string & path,const std::string & file_name)201 bool GenerateJsonSchema(const Parser &parser, const std::string &path,
202                         const std::string &file_name) {
203   jsons::JsonSchemaGenerator generator(parser, path, file_name);
204   return generator.generate();
205 }
206 }  // namespace flatbuffers
207