1// This schema defines objects that represent a parsed schema, like
2// the binary version of a .fbs file.
3// This could be used to operate on unknown FlatBuffers at runtime.
4// It can even ... represent itself (!)
5
6namespace reflection;
7
8// These must correspond to the enum in idl.h.
9enum BaseType : byte {
10 None,
11 UType,
12 Bool,
13 Byte,
14 UByte,
15 Short,
16 UShort,
17 Int,
18 UInt,
19 Long,
20 ULong,
21 Float,
22 Double,
23 String,
24 Vector,
25 Obj, // Used for tables & structs.
26 Union,
27 Array,
28 Vector64,
29
30 // Add any new type above this value.
31 MaxBaseType
32}
33
34table Type {
35 base_type:BaseType;
36 element:BaseType = None; // Only if base_type == Vector
37 // or base_type == Array.
38 index:int = -1; // If base_type == Object, index into "objects" below.
39 // If base_type == Union, UnionType, or integral derived
40 // from an enum, index into "enums" below.
41 // If base_type == Vector && element == Union or UnionType.
42 fixed_length:uint16 = 0; // Only if base_type == Array.
43 /// The size (octets) of the `base_type` field.
44 base_size:uint = 4; // 4 Is a common size due to offsets being that size.
45 /// The size (octets) of the `element` field, if present.
46 element_size:uint = 0;
47}
48
49table KeyValue {
50 key:string (required, key);
51 value:string;
52}
53
54table EnumVal {
55 name:string (required);
56 value:long (key);
57 object:Object (deprecated);
58 union_type:Type;
59 documentation:[string];
60 attributes:[KeyValue];
61}
62
63table Enum {
64 name:string (required, key);
65 values:[EnumVal] (required); // In order of their values.
66 is_union:bool = false;
67 underlying_type:Type (required);
68 attributes:[KeyValue];
69 documentation:[string];
70 /// File that this Enum is declared in.
71 declaration_file: string;
72}
73
74table Field {
75 name:string (required, key);
76 type:Type (required);
77 id:ushort;
78 offset:ushort; // Offset into the vtable for tables, or into the struct.
79 default_integer:long = 0;
80 default_real:double = 0.0;
81 deprecated:bool = false;
82 required:bool = false;
83 key:bool = false;
84 attributes:[KeyValue];
85 documentation:[string];
86 optional:bool = false;
87 /// Number of padding octets to always add after this field. Structs only.
88 padding:uint16 = 0;
89 /// If the field uses 64-bit offsets.
90 offset64:bool = false;
91}
92
93table Object { // Used for both tables and structs.
94 name:string (required, key);
95 fields:[Field] (required); // Sorted.
96 is_struct:bool = false;
97 minalign:int;
98 bytesize:int; // For structs.
99 attributes:[KeyValue];
100 documentation:[string];
101 /// File that this Object is declared in.
102 declaration_file: string;
103}
104
105table RPCCall {
106 name:string (required, key);
107 request:Object (required); // must be a table (not a struct)
108 response:Object (required); // must be a table (not a struct)
109 attributes:[KeyValue];
110 documentation:[string];
111}
112
113table Service {
114 name:string (required, key);
115 calls:[RPCCall];
116 attributes:[KeyValue];
117 documentation:[string];
118 /// File that this Service is declared in.
119 declaration_file: string;
120}
121
122/// New schema language features that are not supported by old code generators.
123enum AdvancedFeatures : ulong (bit_flags) {
124 AdvancedArrayFeatures,
125 AdvancedUnionFeatures,
126 OptionalScalars,
127 DefaultVectorsAndStrings,
128}
129
130/// File specific information.
131/// Symbols declared within a file may be recovered by iterating over all
132/// symbols and examining the `declaration_file` field.
133table SchemaFile {
134 /// Filename, relative to project root.
135 filename:string (required, key);
136 /// Names of included files, relative to project root.
137 included_filenames:[string];
138}
139
140table Schema {
141 objects:[Object] (required); // Sorted.
142 enums:[Enum] (required); // Sorted.
143 file_ident:string;
144 file_ext:string;
145 root_table:Object;
146 services:[Service]; // Sorted.
147 advanced_features:AdvancedFeatures;
148 /// All the files used in this compilation. Files are relative to where
149 /// flatc was invoked.
150 fbs_files:[SchemaFile]; // Sorted.
151}
152
153root_type Schema;
154
155file_identifier "BFBS";
156file_extension "bfbs";
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