util.go

package main

import (
	"fmt"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
)

// Runs a command in dir.
// The name and args are as in exec.Command.
// Stdout, stderr, and the environment are inherited
// from the current process.
func runIn(dir, name string, args ...string) error {
	_, err := runInWithOutput(dir, name, args...)
	return err
}

func runInWithOutput(dir, name string, args ...string) (string, error) {
	c := exec.Command(name, args...)
	c.Dir = dir
	o, err := c.CombinedOutput()

	if debug {
		fmt.Printf("execute: %+v\n", c)
		fmt.Printf(" output: %s\n", string(o))
	}

	return string(o), err
}

// driveLetterToUpper converts Windows path's drive letters to uppercase. This
// is needed when comparing 2 paths with different drive letter case.
func driveLetterToUpper(path string) string {
	if runtime.GOOS != "windows" || path == "" {
		return path
	}

	p := path

	// If path's drive letter is lowercase, change it to uppercase.
	if len(p) >= 2 && p[1] == ':' && 'a' <= p[0] && p[0] <= 'z' {
		p = string(p[0]+'A'-'a') + p[1:]
	}

	return p
}

// clean the path and ensure that a drive letter is upper case (if it exists).
func cleanPath(path string) string {
	return driveLetterToUpper(filepath.Clean(path))
}

// deal with case insensitive filesystems and other weirdness
func pathEqual(a, b string) bool {
	a = cleanPath(a)
	b = cleanPath(b)
	return strings.EqualFold(a, b)
}