// errorOrVoid filters the list of functions to only those that return only an
// error or have no return value.
func errorOrVoid(fns []*ast.FuncDecl, info types.Info) []*ast.FuncDecl {
fds := []*ast.FuncDecl{}
for _, fn := range fns {
// look for functions with 0 or 1 return values
res := fn.Type.Results
if res.NumFields() > 1 {
continue
}
// 0 return value is ok
if res.NumFields() == 0 {
fds = append(fds, fn)
continue
}
// if 1 return value, look for those that return an error
ret := res.List[0]
// handle (a, b, c int)
if len(ret.Names) > 1 {
continue
}
t := info.TypeOf(ret.Type)
if t != nil && t.String() == "error" {
fds = append(fds, fn)
}
}
return fds
}
func functions(f *ast.File, info types.Info, fset *token.FileSet) ([]Function, error) {
fns := exportedFuncs(f, fset)
fns = errorOrVoid(fns, info)
cmtMap := ast.NewCommentMap(fset, f, f.Comments)
functions := make([]Function, len(fns))
for i, fn := range fns {
fun := Function{Name: fn.Name.Name}
fun.Comment = combine(cmtMap[fn])
// we only support null returns or error returns, so if there's a
// return, it's an error.
if len(fn.Type.Results.List) > 0 {
fun.IsError = true
}
params := fn.Type.Params.List
fun.Params = make([]Param, 0, len(params))
for _, field := range params {
t := info.TypeOf(field.Type)
pointer := false
if p, ok := t.(*types.Pointer); ok {
t = p.Elem()
pointer = true
}
if b, ok := t.(*types.Basic); ok {
if b.Kind() == types.UnsafePointer {
log.Printf(
"Can't create command for function %q because its parameter %q is an unsafe.Pointer.",
fn.Name.Name,
field.Names[0])
break
}
fieldCmt := combine(cmtMap[field])
// handle a, b, c int
for _, name := range field.Names {
nameCmt := combine(cmtMap[name])
if nameCmt == "" {
nameCmt = fieldCmt
}
param := Param{
Name: name.Name,
Type: b.Kind(),
IsPointer: pointer,
Comment: nameCmt,
}
fun.Params = append(fun.Params, param)
}
continue
}
}
functions[i] = fun
}
return functions, nil
}