/
fromflags.go
192 lines (174 loc) · 4.13 KB
/
fromflags.go
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package construct
import (
"fmt"
"io"
"io/ioutil"
"reflect"
"strings"
"text/tabwriter"
"time"
"github.com/pierrec/construct/internal/structs"
"github.com/pkg/errors"
flag "github.com/spf13/pflag"
)
func (c *config) buildFlags(section string, root *structs.StructStruct) error {
if c.fs == nil {
c.fs = flag.NewFlagSet("", flag.ContinueOnError)
// Disable the output on error.
c.fs.SetOutput(ioutil.Discard)
// Make sure the parsing stops when a command is found.
c.fs.SetInterspersed(false)
c.refs = make(map[string]interface{})
}
config, ok := root.Interface().(Config)
if !ok {
// Skip non Config structs.
return nil
}
from, isFlags := root.Interface().(FromFlags)
for _, field := range root.Fields() {
if c, _ := getCommand(field); c != nil {
// Skip subcommand.
continue
}
if emb := field.Embedded(); emb != nil {
section := c.toSection(section, emb)
err := c.buildFlags(section, emb)
if err != nil {
return err
}
continue
}
name := c.toName(section, field)
// Convert lower types.
v, err := field.MarshalValue()
if err != nil {
return errors.Errorf("field %s: %v", name, err)
}
lname := strings.ToLower(name)
usage := config.Usage(field.Name())
var short string
if isFlags {
short = from.FlagsShort(field.Name())
short = strings.ToLower(short)
}
// Assign flags and keep track of the pointers of the set value.
var ref interface{}
switch w := v.(type) {
case bool:
ref = c.fs.BoolP(lname, short, w, usage)
case time.Duration:
ref = c.fs.DurationP(lname, short, w, usage)
case float64:
ref = c.fs.Float64P(lname, short, w, usage)
case int:
ref = c.fs.IntP(lname, short, w, usage)
case int64:
ref = c.fs.Int64P(lname, short, w, usage)
case string:
ref = c.fs.StringP(lname, short, w, usage)
case uint:
ref = c.fs.UintP(lname, short, w, usage)
case uint64:
ref = c.fs.Uint64P(lname, short, w, usage)
}
c.refs[lname] = ref
}
return nil
}
func (c *config) buildFlagsUsage() func(io.Writer) error {
type subcommand struct {
s *structs.StructStruct
c Config
}
var subcommands []subcommand
for _, field := range c.root.Fields() {
s, c := getCommand(field)
if s != nil {
subcommands = append(subcommands, subcommand{s, c})
}
}
return func(out io.Writer) (err error) {
// Main usage.
if usage := c.raw.Usage(""); usage != "" {
_, err = fmt.Fprintf(out, "%s\n\n", usage)
if err != nil {
return err
}
}
_, err = fmt.Fprintf(out, "Options:\n")
if err != nil {
return err
}
tabw := tabwriter.NewWriter(out, 8, 0, 1, ' ', 0)
c.fs.VisitAll(func(f *flag.Flag) {
if err != nil {
return
}
if f.Usage == "" {
// Hidden flag.
return
}
refv := c.refs[f.Name]
v := reflect.ValueOf(refv).Elem().Interface()
short := f.Shorthand
if short != "" {
short = "-" + short + ", "
}
switch v.(type) {
case bool:
_, err = fmt.Fprintf(tabw, " %s\t--%s\t", short, f.Name)
default:
_, err = fmt.Fprintf(tabw, " %s\t--%s\t%T", short, f.Name, v)
}
if err == nil {
_, err = fmt.Fprintf(tabw, "\t%s\n", f.Usage)
}
})
if err != nil {
return err
}
if err = tabw.Flush(); err != nil {
return err
}
// Subcommands.
if len(subcommands) > 0 {
_, err = fmt.Fprintf(out, "\nCommands:\n")
if err != nil {
return err
}
for _, sub := range subcommands {
usage := sub.c.Usage("")
if usage == "" {
// Hidden command.
continue
}
cmd := strings.ToLower(sub.s.Name())
_, err = fmt.Fprintf(tabw, "\t%s\t%s\n", cmd, usage)
if err != nil {
return err
}
}
}
return tabw.Flush()
}
}
// The flags that have been updated are removed from the map.
func (c *config) updateFlags() (err error) {
c.fs.Visit(func(f *flag.Flag) {
if err != nil {
return
}
names := c.fromNameAll(f.Name, c.options.gsep)
field := c.root.Lookup(names...)
// Cached references are pointers to the flag set value.
refv := c.refs[f.Name]
v := reflect.ValueOf(refv).Elem().Interface()
err = field.Set(v)
if err != nil {
err = errors.Errorf("flag %s: %v", f.Name, err)
}
delete(c.trans, f.Name)
})
return
}