utils.go

package main

import (
	"errors"
	"fmt"
	"os"
	"runtime"
	"time"

	"github.com/qiniu/log"
)

var ErrGoTimeout = errors.New("GoTimeoutFunc")

func GoFunc(f func() error) chan error {
	ch := make(chan error)
	go func() {
		ch <- f()
	}()
	return ch
}

func GoTimeoutFunc(timeout time.Duration, f func() error) chan error {
	ch := make(chan error)
	go func() {
		var err error
		select {
		case err = <-GoFunc(f):
			ch <- err
		case <-time.After(timeout):
			log.Debugf("timeout: %v", f)
			ch <- ErrGoTimeout
		}
	}()
	return ch
}

func GoTimeout(f func() error, timeout time.Duration) (err error) {
	done := make(chan bool)
	go func() {
		err = f()
		done <- true
	}()
	select {
	case <-time.After(timeout):
		return ErrGoTimeout
	case <-done:
		return
	}
}

func IsDir(dir string) bool {
	fi, err := os.Stat(dir)
	return err == nil && fi.IsDir()
}

func UserHomeDir() string {
	if runtime.GOOS == "windows" {
		home := os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
		if home == "" {
			home = os.Getenv("USERPROFILE")
		}
		return home
	}
	return os.Getenv("HOME")
}

// askForConfirmation uses Scanln to parse user input. A user must type in "yes" or "no" and
// then press enter. It has fuzzy matching, so "y", "Y", "yes", "YES", and "Yes" all count as
// confirmations. If the input is not recognized, it will ask again. The function does not return
// until it gets a valid response from the user. Typically, you should use fmt to print out a question
// before calling askForConfirmation. E.g. fmt.Println("WARNING: Are you sure? (yes/no)")
func askForConfirmation() bool {
	var response string
	_, err := fmt.Scanln(&response)
	if err != nil {
		log.Fatal(err)
	}
	okayResponses := []string{"y", "Y", "yes", "Yes", "YES"}
	nokayResponses := []string{"n", "N", "no", "No", "NO"}
	if containsString(okayResponses, response) {
		return true
	} else if containsString(nokayResponses, response) {
		return false
	} else {
		fmt.Println("Please type yes or no and then press enter:")
		return askForConfirmation()
	}
}

// You might want to put the following two functions in a separate utility package.

// posString returns the first index of element in slice.
// If slice does not contain element, returns -1.
func posString(slice []string, element string) int {
	for index, elem := range slice {
		if elem == element {
			return index
		}
	}
	return -1
}

// containsString returns true iff slice contains element
func containsString(slice []string, element string) bool {
	return !(posString(slice, element) == -1)
}