github.com/hirochachacha/plua@v0.0.0-20170217012138-c82f520cc725/cmd/luafmt/luafmt.go

// Original: src/cmd/gofmt/gofmt.go
//
// Copyright 2009 The Go Authors. All rights reserved.
// Portions Copyright 2016 Hiroshi Ioka. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//    * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

package main

import (
	"bytes"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"

	"github.com/hirochachacha/plua/compiler/ast/printer"
	"github.com/hirochachacha/plua/compiler/parser"
	"github.com/hirochachacha/plua/compiler/scanner"
)

var (
	// main operation modes
	list   = flag.Bool("l", false, "list files whose formatting differs from luafmt's")
	write  = flag.Bool("w", false, "write result to (source) file instead of stdout")
	doDiff = flag.Bool("d", false, "display diffs instead of rewriting files")
)

const (
// tabWidth = 2
// printerMode = printer.UseSpaces | printer.TabIndent
)

var (
	exitCode = 0

	buf bytes.Buffer
)

func report(err error) {
	fmt.Fprintln(os.Stderr, err)
	exitCode = 2
}

func usage() {
	fmt.Fprintf(os.Stderr, "usage: luafmt [flags] [path ...]\n")
	flag.PrintDefaults()
}

func isLuaFile(f os.FileInfo) bool {
	// ignore non-Go files
	name := f.Name()
	return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".lua")
}

func processFile(filename string) error {
	var srcname string
	var r io.Reader
	var src []byte
	var perm os.FileMode = 0644

	if filename == "" {
		srcname = "=stdin"
		r = os.Stdin
	} else {
		srcname = "@" + filename
		f, err := os.Open(filename)
		if err != nil {
			return err
		}
		defer f.Close()
		fi, err := f.Stat()
		if err != nil {
			return err
		}
		src, err = ioutil.ReadAll(f)
		if err != nil {
			return err
		}
		r = bytes.NewReader(src)
		perm = fi.Mode().Perm()
	}

	ast, err := parser.Parse(scanner.Scan(r, srcname, scanner.ScanComments), parser.ParseComments)
	if err != nil {
		return err
	}

	buf.Reset()

	err = printer.Fprint(&buf, ast)
	// err = (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(&buf, ast)
	if err != nil {
		return err
	}

	res := buf.Bytes()

	if !bytes.Equal(src, res) {
		// formatting has changed
		if *list {
			fmt.Fprintln(os.Stdout, filename)
		}
		if *write {
			// make a temporary backup before overwriting original
			bakname, err := backupFile(filename+".", src, perm)
			if err != nil {
				return err
			}
			err = ioutil.WriteFile(filename, res, perm)
			if err != nil {
				os.Rename(bakname, filename)
				return err
			}
			err = os.Remove(bakname)
			if err != nil {
				return err
			}
		}
		if *doDiff {
			data, err := diff(src, res)
			if err != nil {
				return fmt.Errorf("computing diff: %s", err)
			}
			fmt.Printf("diff %s luafmt/%s\n", filename, filename)
			os.Stdout.Write(data)
		}
	}

	if !*list && !*write && !*doDiff {
		_, err = os.Stdout.Write(res)
	}

	return err
}

func visitFile(path string, f os.FileInfo, err error) error {
	if err == nil && isLuaFile(f) {
		err = processFile(path)
	}
	// Don't complain if a file was deleted in the meantime (i.e.
	// the directory changed concurrently while running luafmt).
	if err != nil && !os.IsNotExist(err) {
		report(err)
	}
	return nil
}

func walkDir(path string) {
	filepath.Walk(path, visitFile)
}

func main() {
	// call luafmtMain in a separate function
	// so that it can use defer and have them
	// run before the exit.
	luafmtMain()
	os.Exit(exitCode)
}

func luafmtMain() {
	flag.Usage = usage
	flag.Parse()

	if flag.NArg() == 0 {
		if *write {
			fmt.Fprintln(os.Stderr, "error: cannot use -w with standard input")
			exitCode = 2
			return
		}
		if err := processFile(""); err != nil {
			report(err)
		}
		return
	}

	for i := 0; i < flag.NArg(); i++ {
		path := flag.Arg(i)
		switch dir, err := os.Stat(path); {
		case err != nil:
			report(err)
		case dir.IsDir():
			walkDir(path)
		default:
			if err := processFile(path); err != nil {
				report(err)
			}
		}
	}
}

func diff(b1, b2 []byte) (data []byte, err error) {
	f1, err := ioutil.TempFile("", "luafmt")
	if err != nil {
		return
	}
	defer os.Remove(f1.Name())
	defer f1.Close()

	f2, err := ioutil.TempFile("", "luafmt")
	if err != nil {
		return
	}
	defer os.Remove(f2.Name())
	defer f2.Close()

	f1.Write(b1)
	f2.Write(b2)

	data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).CombinedOutput()
	if len(data) > 0 {
		// diff exits with a non-zero status when the files don't match.
		// Ignore that failure as long as we get output.
		err = nil
	}
	return

}

const chmodSupported = runtime.GOOS != "windows"

// backupFile writes data to a new file named filename<number> with permissions perm,
// with <number randomly chosen such that the file name is unique. backupFile returns
// the chosen file name.
func backupFile(filename string, data []byte, perm os.FileMode) (string, error) {
	// create backup file
	f, err := ioutil.TempFile(filepath.Dir(filename), filepath.Base(filename))
	if err != nil {
		return "", err
	}
	bakname := f.Name()
	if chmodSupported {
		err = f.Chmod(perm)
		if err != nil {
			f.Close()
			os.Remove(bakname)
			return bakname, err
		}
	}

	// write data to backup file
	n, err := f.Write(data)
	if err == nil && n < len(data) {
		err = io.ErrShortWrite
	}
	if err1 := f.Close(); err == nil {
		err = err1
	}

	return bakname, err
}