package common
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import (
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"bufio"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"os/signal"
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"strings"
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)
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var (
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GoPath = os.Getenv("GOPATH")
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)
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func TrapSignal(cb func()) {
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c := make(chan os.Signal, 1)
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signal.Notify(c, os.Interrupt)
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signal.Notify(c, os.Kill)
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go func() {
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for sig := range c {
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fmt.Printf("captured %v, exiting...\n", sig)
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if cb != nil {
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cb()
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}
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os.Exit(1)
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}
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}()
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select {}
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}
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func Exit(s string) {
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fmt.Printf(s + "\n")
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os.Exit(1)
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}
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func EnsureDir(dir string, mode os.FileMode) error {
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if _, err := os.Stat(dir); os.IsNotExist(err) {
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err := os.MkdirAll(dir, mode)
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if err != nil {
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return fmt.Errorf("Could not create directory %v. %v", dir, err)
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}
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}
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return nil
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}
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func IsDirEmpty(name string) (bool, error) {
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f, err := os.Open(name)
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if err != nil {
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return true, err //folder is non-existent
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}
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defer f.Close()
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_, err = f.Readdirnames(1) // Or f.Readdir(1)
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if err == io.EOF {
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return true, nil
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}
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return false, err // Either not empty or error, suits both cases
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}
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func FileExists(filePath string) bool {
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_, err := os.Stat(filePath)
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return !os.IsNotExist(err)
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}
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func ReadFile(filePath string) ([]byte, error) {
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return ioutil.ReadFile(filePath)
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}
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func MustReadFile(filePath string) []byte {
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fileBytes, err := ioutil.ReadFile(filePath)
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if err != nil {
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Exit(Fmt("MustReadFile failed: %v", err))
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return nil
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}
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return fileBytes
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}
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func WriteFile(filePath string, contents []byte, mode os.FileMode) error {
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err := ioutil.WriteFile(filePath, contents, mode)
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if err != nil {
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return err
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}
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// fmt.Printf("File written to %v.\n", filePath)
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return nil
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}
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func MustWriteFile(filePath string, contents []byte, mode os.FileMode) {
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err := WriteFile(filePath, contents, mode)
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if err != nil {
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Exit(Fmt("MustWriteFile failed: %v", err))
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}
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}
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// Writes to newBytes to filePath.
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// Guaranteed not to lose *both* oldBytes and newBytes,
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// (assuming that the OS is perfect)
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func WriteFileAtomic(filePath string, newBytes []byte, mode os.FileMode) error {
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// If a file already exists there, copy to filePath+".bak" (overwrite anything)
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if _, err := os.Stat(filePath); !os.IsNotExist(err) {
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fileBytes, err := ioutil.ReadFile(filePath)
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if err != nil {
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return fmt.Errorf("Could not read file %v. %v", filePath, err)
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}
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err = ioutil.WriteFile(filePath+".bak", fileBytes, mode)
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if err != nil {
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return fmt.Errorf("Could not write file %v. %v", filePath+".bak", err)
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}
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}
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// Write newBytes to filePath.new
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err := ioutil.WriteFile(filePath+".new", newBytes, mode)
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if err != nil {
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return fmt.Errorf("Could not write file %v. %v", filePath+".new", err)
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}
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// Move filePath.new to filePath
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err = os.Rename(filePath+".new", filePath)
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return err
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}
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//--------------------------------------------------------------------------------
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func Tempfile(prefix string) (*os.File, string) {
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file, err := ioutil.TempFile("", prefix)
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if err != nil {
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PanicCrisis(err)
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}
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return file, file.Name()
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}
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func Tempdir(prefix string) (*os.File, string) {
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tempDir := os.TempDir() + "/" + prefix + RandStr(12)
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err := EnsureDir(tempDir, 0700)
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if err != nil {
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panic(Fmt("Error creating temp dir: %v", err))
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}
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dir, err := os.Open(tempDir)
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if err != nil {
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panic(Fmt("Error opening temp dir: %v", err))
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}
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return dir, tempDir
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}
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//--------------------------------------------------------------------------------
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func Prompt(prompt string, defaultValue string) (string, error) {
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fmt.Print(prompt)
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reader := bufio.NewReader(os.Stdin)
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line, err := reader.ReadString('\n')
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if err != nil {
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return defaultValue, err
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} else {
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line = strings.TrimSpace(line)
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if line == "" {
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return defaultValue, nil
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}
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return line, nil
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}
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}
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