1// Mostly copied from Go's src/cmd/gofmt:
2// Copyright 2009 The Go Authors. All rights reserved.
3// Use of this source code is governed by a BSD-style
4// license that can be found in the LICENSE file.
5
6package main
7
8import (
9	"bytes"
10	"flag"
11	"fmt"
12	"github.com/google/blueprint/parser"
13	"io"
14	"io/ioutil"
15	"os"
16	"os/exec"
17	"path/filepath"
18)
19
20var (
21	// main operation modes
22	list      = flag.Bool("l", false, "list files whose formatting differs from bpfmt's")
23	write     = flag.Bool("w", false, "write result to (source) file instead of stdout")
24	doDiff    = flag.Bool("d", false, "display diffs instead of rewriting files")
25	sortLists = flag.Bool("s", false, "sort arrays")
26)
27
28var (
29	exitCode = 0
30)
31
32func report(err error) {
33	fmt.Fprintln(os.Stderr, err)
34	exitCode = 2
35}
36
37func usage() {
38	fmt.Fprintf(os.Stderr, "usage: bpfmt [flags] [path ...]\n")
39	flag.PrintDefaults()
40	os.Exit(2)
41}
42
43// If in == nil, the source is the contents of the file with the given filename.
44func processFile(filename string, in io.Reader, out io.Writer) error {
45	if in == nil {
46		f, err := os.Open(filename)
47		if err != nil {
48			return err
49		}
50		defer f.Close()
51		in = f
52	}
53
54	src, err := ioutil.ReadAll(in)
55	if err != nil {
56		return err
57	}
58
59	r := bytes.NewBuffer(src)
60
61	file, errs := parser.Parse(filename, r, parser.NewScope(nil))
62	if len(errs) > 0 {
63		for _, err := range errs {
64			fmt.Fprintln(os.Stderr, err)
65		}
66		return fmt.Errorf("%d parsing errors", len(errs))
67	}
68
69	if *sortLists {
70		parser.SortLists(file)
71	}
72
73	res, err := parser.Print(file)
74	if err != nil {
75		return err
76	}
77
78	if !bytes.Equal(src, res) {
79		// formatting has changed
80		if *list {
81			fmt.Fprintln(out, filename)
82		}
83		if *write {
84			err = ioutil.WriteFile(filename, res, 0644)
85			if err != nil {
86				return err
87			}
88		}
89		if *doDiff {
90			data, err := diff(src, res)
91			if err != nil {
92				return fmt.Errorf("computing diff: %s", err)
93			}
94			fmt.Printf("diff %s bpfmt/%s\n", filename, filename)
95			out.Write(data)
96		}
97	}
98
99	if !*list && !*write && !*doDiff {
100		_, err = out.Write(res)
101	}
102
103	return err
104}
105
106func visitFile(path string, f os.FileInfo, err error) error {
107	if err == nil && f.Name() == "Blueprints" {
108		err = processFile(path, nil, os.Stdout)
109	}
110	if err != nil {
111		report(err)
112	}
113	return nil
114}
115
116func walkDir(path string) {
117	filepath.Walk(path, visitFile)
118}
119
120func main() {
121	flag.Parse()
122
123	if flag.NArg() == 0 {
124		if *write {
125			fmt.Fprintln(os.Stderr, "error: cannot use -w with standard input")
126			exitCode = 2
127			return
128		}
129		if err := processFile("<standard input>", os.Stdin, os.Stdout); err != nil {
130			report(err)
131		}
132		return
133	}
134
135	for i := 0; i < flag.NArg(); i++ {
136		path := flag.Arg(i)
137		switch dir, err := os.Stat(path); {
138		case err != nil:
139			report(err)
140		case dir.IsDir():
141			walkDir(path)
142		default:
143			if err := processFile(path, nil, os.Stdout); err != nil {
144				report(err)
145			}
146		}
147	}
148}
149
150func diff(b1, b2 []byte) (data []byte, err error) {
151	f1, err := ioutil.TempFile("", "bpfmt")
152	if err != nil {
153		return
154	}
155	defer os.Remove(f1.Name())
156	defer f1.Close()
157
158	f2, err := ioutil.TempFile("", "bpfmt")
159	if err != nil {
160		return
161	}
162	defer os.Remove(f2.Name())
163	defer f2.Close()
164
165	f1.Write(b1)
166	f2.Write(b2)
167
168	data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).CombinedOutput()
169	if len(data) > 0 {
170		// diff exits with a non-zero status when the files don't match.
171		// Ignore that failure as long as we get output.
172		err = nil
173	}
174	return
175
176}
177