initial commit

Author: rogpeppe

exec.go

@@ -0,0 +1,57 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+	"sync"
+
+	"gopkg.in/errgo.v2/fmt/errors"
+)
+
+func runCmd(dir string, name string, args ...string) (string, error) {
+	var outData, errData bytes.Buffer
+	if *printCommands {
+		printShellCommand(dir, name, args)
+	}
+	c := exec.Command(name, args...)
+	c.Stdout = &outData
+	c.Stderr = &errData
+	c.Dir = dir
+	err := c.Run()
+	if err == nil {
+		return outData.String(), nil
+	}
+	if _, ok := err.(*exec.ExitError); ok && errData.Len() > 0 {
+		return "", errors.New(strings.TrimSpace(errData.String()))
+	}
+	return "", fmt.Errorf("cannot run %q: %v", append([]string{name}, args...), err)
+}
+
+var (
+	outputDirMutex sync.Mutex
+	outputDir      string
+)
+
+func printShellCommand(dir, name string, args []string) {
+	outputDirMutex.Lock()
+	defer outputDirMutex.Unlock()
+	if dir != outputDir {
+		fmt.Fprintf(os.Stderr, "cd %s\n", shquote(dir))
+		outputDir = dir
+	}
+	var buf bytes.Buffer
+	buf.WriteString(name)
+	for _, arg := range args {
+		buf.WriteString(" ")
+		buf.WriteString(shquote(arg))
+	}
+	fmt.Fprintf(os.Stderr, "%s\n", buf.Bytes())
+}
+
+func shquote(s string) string {
+	// single-quote becomes single-quote, double-quote, single-quote, double-quote, single-quote
+	return `'` + strings.Replace(s, `'`, `'"'"'`, -1) + `'`
+}