/
prediction.go
271 lines (243 loc) · 6.19 KB
/
prediction.go
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package kongcompletion
import (
"fmt"
"github.com/alecthomas/kong"
"github.com/posener/complete"
)
const predictorTag = "predictor"
type options struct {
predictors map[string]complete.Predictor
exitFunc func(code int)
errorHandler func(error)
overrides map[string]bool
}
// Option is a configuration option for running Register
type Option func(*options)
// WithPredictor use the named predictor
func WithPredictor(name string, predictor complete.Predictor) Option {
return func(o *options) {
if o.predictors == nil {
o.predictors = map[string]complete.Predictor{}
}
o.predictors[name] = predictor
}
}
// WithPredictors use these predictors
func WithPredictors(predictors map[string]complete.Predictor) Option {
return func(o *options) {
for k, v := range predictors {
WithPredictor(k, v)(o)
}
}
}
// WithExitFunc the exit command that is run after completions
func WithExitFunc(exitFunc func(code int)) Option {
return func(o *options) {
o.exitFunc = exitFunc
}
}
// WithErrorHandler handle errors with completions
func WithErrorHandler(handler func(error)) Option {
return func(o *options) {
o.errorHandler = handler
}
}
// WithFlagOverrides registers overrides for hidden commands / flags
func WithFlagOverrides(overrides ...map[string]bool) Option {
allOverrides := make(map[string]bool)
for _, os := range overrides {
for k, v := range os {
allOverrides[k] = v
}
}
return func(o *options) {
o.overrides = allOverrides
}
}
func (o *options) Skip(f *kong.Flag) bool {
doShow, wasSet := o.overrides[f.Name]
if !wasSet {
return f.Hidden
}
return !doShow
}
func buildOptions(opt ...Option) *options {
opts := &options{
predictors: map[string]complete.Predictor{},
}
for _, o := range opt {
o(opts)
}
return opts
}
// Command returns a completion Command for a kong parser
func Command(parser *kong.Kong, opt ...Option) (complete.Command, error) {
opts := buildOptions(opt...)
if parser == nil || parser.Model == nil {
return complete.Command{}, nil
}
command, err := nodeCommand(parser.Model.Node, opts)
if err != nil {
return complete.Command{}, err
}
return *command, err
}
// Register configures a kong app for intercepting completions.
func Register(parser *kong.Kong, opt ...Option) {
if parser == nil {
return
}
opts := buildOptions(opt...)
errHandler := opts.errorHandler
if errHandler == nil {
errHandler = func(err error) {
parser.Errorf("error running command completion: %v", err)
}
}
exitFunc := opts.exitFunc
if exitFunc == nil {
exitFunc = parser.Exit
}
cmd, err := Command(parser, opt...)
if err != nil {
errHandler(err)
exitFunc(1)
}
cmp := complete.New(parser.Model.Name, cmd)
cmp.Out = parser.Stdout
done := cmp.Complete()
if done {
exitFunc(0)
}
}
func nodeCommand(node *kong.Node, opts *options) (*complete.Command, error) {
if node == nil {
return nil, nil
}
cmd := complete.Command{
Sub: complete.Commands{},
GlobalFlags: complete.Flags{},
}
for _, child := range node.Children {
if child == nil || child.Hidden {
continue
}
childCmd, err := nodeCommand(child, opts)
if err != nil {
return nil, err
}
if childCmd != nil {
cmd.Sub[child.Name] = *childCmd
}
}
for _, flag := range node.Flags {
if flag == nil || opts.Skip(flag) {
continue
}
predictor, err := flagPredictor(flag, opts.predictors)
if err != nil {
return nil, err
}
for _, f := range flagNamesWithHyphens(flag) {
cmd.GlobalFlags[f] = predictor
}
}
boolFlags, nonBoolFlags := boolAndNonBoolFlags(node.Flags)
pps, err := positionalPredictors(node.Positional, opts.predictors)
if err != nil {
return nil, err
}
cmd.Args = &PositionalPredictor{
Predictors: pps,
ArgFlags: flagNamesWithHyphens(nonBoolFlags...),
BoolFlags: flagNamesWithHyphens(boolFlags...),
}
return &cmd, nil
}
func flagNamesWithHyphens(flags ...*kong.Flag) []string {
names := make([]string, 0, len(flags)*2)
if flags == nil {
return names
}
for _, flag := range flags {
names = append(names, "--"+flag.Name)
if flag.Short != 0 {
names = append(names, "-"+string(flag.Short))
}
}
return names
}
// boolAndNonBoolFlags divides a list of flags into boolean and non-boolean flags
func boolAndNonBoolFlags(flags []*kong.Flag) (boolFlags, nonBoolFlags []*kong.Flag) {
boolFlags = make([]*kong.Flag, 0, len(flags))
nonBoolFlags = make([]*kong.Flag, 0, len(flags))
for _, flag := range flags {
switch flag.Value.IsBool() {
case true:
boolFlags = append(boolFlags, flag)
case false:
nonBoolFlags = append(nonBoolFlags, flag)
}
}
return boolFlags, nonBoolFlags
}
// kongTag interface for *kong.kongTag
type kongTag interface {
Has(string) bool
Get(string) string
}
func tagPredictor(tag kongTag, predictors map[string]complete.Predictor) (complete.Predictor, error) {
if tag == nil {
return nil, nil
}
if !tag.Has(predictorTag) {
return nil, nil
}
if predictors == nil {
predictors = map[string]complete.Predictor{}
}
predictorName := tag.Get(predictorTag)
predictor, ok := predictors[predictorName]
if !ok {
return nil, fmt.Errorf("no predictor with name %q", predictorName)
}
return predictor, nil
}
func valuePredictor(value *kong.Value, predictors map[string]complete.Predictor) (complete.Predictor, error) {
if value == nil {
return nil, nil
}
predictor, err := tagPredictor(value.Tag, predictors)
if err != nil {
return nil, err
}
if predictor != nil {
return predictor, nil
}
switch {
case value.IsBool():
return complete.PredictNothing, nil
case value.Enum != "":
enumVals := make([]string, 0, len(value.EnumMap()))
for enumVal := range value.EnumMap() {
enumVals = append(enumVals, enumVal)
}
return complete.PredictSet(enumVals...), nil
default:
return complete.PredictAnything, nil
}
}
func positionalPredictors(args []*kong.Positional, predictors map[string]complete.Predictor) ([]complete.Predictor, error) {
res := make([]complete.Predictor, len(args))
var err error
for i, arg := range args {
res[i], err = valuePredictor(arg, predictors)
if err != nil {
return nil, err
}
}
return res, nil
}
func flagPredictor(flag *kong.Flag, predictors map[string]complete.Predictor) (complete.Predictor, error) {
return valuePredictor(flag.Value, predictors)
}