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98 lines
2.2 KiB
98 lines
2.2 KiB
package common
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import (
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"fmt"
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"io/ioutil"
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"os"
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"os/signal"
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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) error {
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if _, err := os.Stat(dir); os.IsNotExist(err) {
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err := os.MkdirAll(dir, 0700)
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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 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) error {
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err := ioutil.WriteFile(filePath, contents, 0600)
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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) {
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err := WriteFile(filePath, contents)
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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) 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, 0600)
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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, 0600)
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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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