163 lines
3.6 KiB
Go
163 lines
3.6 KiB
Go
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package main
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import (
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"errors"
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"fmt"
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"go/ast"
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"go/parser"
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"go/token"
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"reflect"
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"strings"
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)
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var ErrBadReturn = errors.New("found return arg with no name: all args must be named")
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type ErrUnexpectedType struct {
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expected string
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actual interface{}
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}
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func (e ErrUnexpectedType) Error() string {
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return fmt.Sprintf("got wrong type expecting %s, got: %v", e.expected, reflect.TypeOf(e.actual))
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}
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type parsedPkg struct {
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Name string
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Functions []function
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}
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type function struct {
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Name string
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Args []arg
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Returns []arg
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Doc string
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}
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type arg struct {
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Name string
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ArgType string
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}
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func (a *arg) String() string {
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return strings.ToLower(a.Name) + " " + strings.ToLower(a.ArgType)
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}
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// Parses the given file for an interface definition with the given name
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func Parse(filePath string, objName string) (*parsedPkg, error) {
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fs := token.NewFileSet()
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pkg, err := parser.ParseFile(fs, filePath, nil, parser.AllErrors)
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if err != nil {
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return nil, err
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}
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p := &parsedPkg{}
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p.Name = pkg.Name.Name
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obj, exists := pkg.Scope.Objects[objName]
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if !exists {
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return nil, fmt.Errorf("could not find object %s in %s", objName, filePath)
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}
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if obj.Kind != ast.Typ {
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return nil, fmt.Errorf("exected type, got %s", obj.Kind)
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}
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spec, ok := obj.Decl.(*ast.TypeSpec)
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if !ok {
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return nil, ErrUnexpectedType{"*ast.TypeSpec", obj.Decl}
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}
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iface, ok := spec.Type.(*ast.InterfaceType)
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if !ok {
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return nil, ErrUnexpectedType{"*ast.InterfaceType", spec.Type}
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}
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p.Functions, err = parseInterface(iface)
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if err != nil {
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return nil, err
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}
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return p, nil
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}
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func parseInterface(iface *ast.InterfaceType) ([]function, error) {
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var functions []function
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for _, field := range iface.Methods.List {
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switch f := field.Type.(type) {
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case *ast.FuncType:
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method, err := parseFunc(field)
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if err != nil {
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return nil, err
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}
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if method == nil {
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continue
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}
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functions = append(functions, *method)
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case *ast.Ident:
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spec, ok := f.Obj.Decl.(*ast.TypeSpec)
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if !ok {
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return nil, ErrUnexpectedType{"*ast.TypeSpec", f.Obj.Decl}
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}
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iface, ok := spec.Type.(*ast.InterfaceType)
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if !ok {
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return nil, ErrUnexpectedType{"*ast.TypeSpec", spec.Type}
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}
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funcs, err := parseInterface(iface)
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if err != nil {
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fmt.Println(err)
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continue
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}
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functions = append(functions, funcs...)
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default:
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return nil, ErrUnexpectedType{"*astFuncType or *ast.Ident", f}
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}
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}
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return functions, nil
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}
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func parseFunc(field *ast.Field) (*function, error) {
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f := field.Type.(*ast.FuncType)
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method := &function{Name: field.Names[0].Name}
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if _, exists := skipFuncs[method.Name]; exists {
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fmt.Println("skipping:", method.Name)
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return nil, nil
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}
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if f.Params != nil {
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args, err := parseArgs(f.Params.List)
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if err != nil {
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return nil, err
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}
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method.Args = args
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}
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if f.Results != nil {
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returns, err := parseArgs(f.Results.List)
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if err != nil {
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return nil, fmt.Errorf("error parsing function returns for %q: %v", method.Name, err)
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}
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method.Returns = returns
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}
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return method, nil
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}
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func parseArgs(fields []*ast.Field) ([]arg, error) {
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var args []arg
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for _, f := range fields {
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if len(f.Names) == 0 {
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return nil, ErrBadReturn
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}
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for _, name := range f.Names {
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var typeName string
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switch argType := f.Type.(type) {
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case *ast.Ident:
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typeName = argType.Name
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case *ast.StarExpr:
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i, ok := argType.X.(*ast.Ident)
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if !ok {
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return nil, ErrUnexpectedType{"*ast.Ident", f.Type}
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}
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typeName = "*" + i.Name
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default:
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return nil, ErrUnexpectedType{"*ast.Ident or *ast.StarExpr", f.Type}
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}
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args = append(args, arg{name.Name, typeName})
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}
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}
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return args, nil
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}
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