108 lines
2.3 KiB
Go
108 lines
2.3 KiB
Go
package clifmt
|
|
|
|
import (
|
|
"fmt"
|
|
"reflect"
|
|
"strings"
|
|
)
|
|
|
|
var ErrNoNewline = fmt.Errorf("no newline allowed in progress mode")
|
|
|
|
// Printpf prints a progress (dynamic) line that rewrites itself
|
|
// on arguments' update
|
|
func Printpf(format string, args ...interface{}) error {
|
|
|
|
// 1. check format
|
|
if strings.ContainsAny(format, "\n\r") {
|
|
return ErrNoNewline
|
|
}
|
|
|
|
// 2. init
|
|
fixed := make([]interface{}, len(args), len(args)) // actual values
|
|
update := make([]chan interface{}, 0, len(args)) // channels that update values
|
|
updateIndex := make([]int, 0, len(args)) // association [order -> index in @fixed]
|
|
|
|
// 3. manage fixed values vs. updatable values (channels)
|
|
for i, arg := range args {
|
|
|
|
// channel -> keep Zero value + store channel
|
|
if reflect.TypeOf(arg).Kind() == reflect.Chan {
|
|
updateIndex = append(updateIndex, i)
|
|
update = append(update, arg.(chan interface{}))
|
|
continue
|
|
}
|
|
|
|
// raw -> set value
|
|
fixed[i] = arg
|
|
}
|
|
|
|
// 4. launch dynamic select for each channel
|
|
maxlen := 0
|
|
nselect(update, func(i int, value interface{}, ok bool) {
|
|
|
|
// channel is closed -> do nothing
|
|
if !ok {
|
|
return
|
|
}
|
|
|
|
// extract real index
|
|
index := updateIndex[i]
|
|
|
|
// update value
|
|
fixed[index] = value
|
|
|
|
// ignore on errors (updatable values still NIL)
|
|
str, err := Sprintf(format, fixed...)
|
|
if err != nil {
|
|
return
|
|
}
|
|
reallen := displaySize(str)
|
|
|
|
// print string
|
|
fmt.Printf("\r%s", str)
|
|
|
|
// pad right to end of max size
|
|
if reallen < maxlen {
|
|
pad := make([]byte, 0, maxlen-reallen)
|
|
for i := reallen; i < maxlen; i++ {
|
|
pad = append(pad, ' ')
|
|
}
|
|
fmt.Printf("%s", pad)
|
|
} else {
|
|
maxlen = reallen
|
|
}
|
|
|
|
})
|
|
|
|
fmt.Printf("\n")
|
|
|
|
return nil
|
|
|
|
}
|
|
|
|
// nselect selects on N channels
|
|
func nselect(channels []chan interface{}, handler func(int, interface{}, bool)) {
|
|
|
|
// 1. build the case list containing each channel
|
|
cases := make([]reflect.SelectCase, len(channels))
|
|
for i, ch := range channels {
|
|
cases[i] = reflect.SelectCase{Dir: reflect.SelectRecv, Chan: reflect.ValueOf(ch)}
|
|
}
|
|
|
|
// 2. wait for selections
|
|
remaining := len(cases)
|
|
for remaining > 0 {
|
|
index, value, ok := reflect.Select(cases)
|
|
|
|
// (1) Closed
|
|
if !ok {
|
|
cases[index].Chan = reflect.ValueOf(nil)
|
|
remaining--
|
|
continue
|
|
}
|
|
|
|
// (2) Received data
|
|
handler(index, value, ok)
|
|
}
|
|
}
|