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fbs

A parser for flatbuffers in Go.

Getting Started

1. Import package fbs:

import "trpc.group/trpc-go/fbs"

2. Pass in the flatbuffers file list you want to parse. Create a Parser and call ParseFiles.

filenames := []string{
    "./file1.fbs", // Pass in a list of flatbuffers files. 
    "./file2.fbs",
}
p := fbs.NewParser()
fds, err := p.ParseFiles(filenames...)
fd1 := fds[0] // The parsed result(descriptor) of file1.fbs
fd2 := fds[1] // The parsed result(descriptor) of file2.fbs

You can access the resulting descriptors from fbs and get rich information about every method definition of rpc services, e.g. method names, input/output type, client/server streaming, etc.

The descriptor SchemaDesc for every file has the following fields:

// SchemaDesc describes a complete .fbs file.
type SchemaDesc struct {
	// Schema stores the root node of the AST.
	Schema *ast.SchemaNode
	// Name stores the .fbs file name.
	Name string
	// Namespace of schema will change in the course of processing each decl, these will be stored
	// in this slice. Decls of table/struct/enum/union will set their own namespaces to be the last
	// namespace in this slice.
	// See parseResult.createSchemaDescriptor.
	Namespaces []string
	// Root stores root_type declaration in flatbuffers file.
	Root string
	// FileExt stores file_extension declaration in flatbuffers file.
	FileExt string
	// FileIdent stores file_identifier declaration in flatbuffers file.
	FileIdent string
	// Attrs stores attributes definitions in flatbuffers file.
	Attrs []string
	// Includes stores all included file names.
	Includes []string
	// Dependencies stores all descriptors corresponding to included files.
	Dependencies []*SchemaDesc
	// Tables stores all table descriptors.
	Tables []*TableDesc
	// Structs stores all struct descriptors.
	Structs []*StructDesc
	// Enums stores all enum descriptors.
	Enums []*EnumDesc
	// Unions stores all union descriptors.
	Unions []*UnionDesc
	// RPCs stores all rpc service descriptors.
	RPCs []*RPCDesc
}

Through accessing these fields such as RPCs, you can get information defined in flatbuffers to get related work done(e.g. generate stub files for rpc services).

Project Structure

.
├── desc.go         # Definitions of descriptors for all kinds of node. 
├── desc_test.go    
├── doc.go          
├── docs            # Documents of implementation.
├── errors.go       # Error handling.
├── errors_test.go  
├── fbsfiles        # Places .fbs for testing. 
├── fbs.y           # Hand-written according to the grammar of flatbuffers. 
├── fbs.y.go        # Generated by fbs.y, used to parse token stream to AST.
├── go.mod          
├── go.sum          
├── internal        
│   └── ast         # Stores definitions and constructions of nodes in AST. 
├── lexer.go        # lexer implementation.
├── lexer_test.go   
├── linker.go       # linker implementation.
├── linker_test.go  
├── parse_result.go # Definition for parsed result.
├── parser.go       # parser implementation.
├── parser_test.go  
├── reader.go       # reader implementation.
├── README.md       
└── scope.go        # scope implementation.

Further information see implementation details

Used in Practice

This project enables trpc-go to have flatbuffers support.

Copyright

The copyright notice pertaining to the Tencent code in this repo was previously in the name of “THL A29 Limited.” That entity has now been de-registered. You should treat all previously distributed copies of the code as if the copyright notice was in the name of “Tencent.”