gopls/internal/fastwalk/fastwalk

1	// Copyright 2016 The Go Authors. All rights reserved.
2	// Use of this source code is governed by a BSD-style
3	// license that can be found in the LICENSE file.
4
5	package fastwalk_test
6
7	import (
8	"bytes"
9	"flag"
10	"fmt"
11	"io/ioutil"
12	"os"
13	"path/filepath"
14	"reflect"
15	"runtime"
16	"sort"
17	"strings"
18	"sync"
19	"testing"
20
21	"golang.org/x/tools/internal/fastwalk"
22	)
23
24	func formatFileModes(m map[string]os.FileMode) string {
25	var keys []string
26	for k := range m {
27	keys = append(keys, k)
28	}
29	sort.Strings(keys)
30	var buf bytes.Buffer
31	for _, k := range keys {
32	fmt.Fprintf(&buf, "%-20s: %v\n", k, m[k])
33	}
34	return buf.String()
35	}
36
37	func testFastWalk(t *testing.T, files map[string]string, callback func(path string, typ os.FileMode) error, want map[string]os.FileMode) {
38	tempdir, err := ioutil.TempDir("", "test-fast-walk")
39	if err != nil {
40	t.Fatal(err)
41	}
42	defer os.RemoveAll(tempdir)
43
44	symlinks := map[string]string{}
45	for path, contents := range files {
46	file := filepath.Join(tempdir, "/src", path)
47	if err := os.MkdirAll(filepath.Dir(file), 0755); err != nil {
48	t.Fatal(err)
49	}
50	var err error
51	if strings.HasPrefix(contents, "LINK:") {
52	symlinks[file] = filepath.FromSlash(strings.TrimPrefix(contents, "LINK:"))
53	} else {
54	err = ioutil.WriteFile(file, []byte(contents), 0644)
55	}
56	if err != nil {
57	t.Fatal(err)
58	}
59	}
60
61	// Create symlinks after all other files. Otherwise, directory symlinks on
62	// Windows are unusable (see https://golang.org/issue/39183).
63	for file, dst := range symlinks {
64	err = os.Symlink(dst, file)
65	if err != nil {
66	if writeErr := ioutil.WriteFile(file, []byte(dst), 0644); writeErr == nil {
67	// Couldn't create symlink, but could write the file.
68	// Probably this filesystem doesn't support symlinks.
69	// (Perhaps we are on an older Windows and not running as administrator.)
70	t.Skipf("skipping because symlinks appear to be unsupported: %v", err)
71	}
72	}
73	}
74
75	got := map[string]os.FileMode{}
76	var mu sync.Mutex
77	err = fastwalk.Walk(tempdir, func(path string, typ os.FileMode) error {
78	mu.Lock()
79	defer mu.Unlock()
80	if !strings.HasPrefix(path, tempdir) {
81	t.Errorf("bogus prefix on %q, expect %q", path, tempdir)
82	}
83	key := filepath.ToSlash(strings.TrimPrefix(path, tempdir))
84	if old, dup := got[key]; dup {
85	t.Errorf("callback called twice for key %q: %v -> %v", key, old, typ)
86	}
87	got[key] = typ
88	return callback(path, typ)
89	})
90
91	if err != nil {
92	t.Fatalf("callback returned: %v", err)
93	}
94	if !reflect.DeepEqual(got, want) {
95	t.Errorf("walk mismatch.\n got:\n%v\nwant:\n%v", formatFileModes(got), formatFileModes(want))
96	}
97	}
98
99	func TestFastWalk_Basic(t *testing.T) {
100	testFastWalk(t, map[string]string{
101	"foo/foo.go": "one",
102	"bar/bar.go": "two",
103	"skip/skip.go": "skip",
104	},
105	func(path string, typ os.FileMode) error {
106	return nil
107	},
108	map[string]os.FileMode{
109	"": os.ModeDir,
110	"/src": os.ModeDir,
111	"/src/bar": os.ModeDir,
112	"/src/bar/bar.go": 0,
113	"/src/foo": os.ModeDir,
114	"/src/foo/foo.go": 0,
115	"/src/skip": os.ModeDir,
116	"/src/skip/skip.go": 0,
117	})
118	}
119
120	func TestFastWalk_LongFileName(t *testing.T) {
121	longFileName := strings.Repeat("x", 255)
122
123	testFastWalk(t, map[string]string{
124	longFileName: "one",
125	},
126	func(path string, typ os.FileMode) error {
127	return nil
128	},
129	map[string]os.FileMode{
130	"": os.ModeDir,
131	"/src": os.ModeDir,
132	"/src/" + longFileName: 0,
133	},
134	)
135	}
136
137	func TestFastWalk_Symlink(t *testing.T) {
138	testFastWalk(t, map[string]string{
139	"foo/foo.go": "one",
140	"bar/bar.go": "LINK:../foo/foo.go",
141	"symdir": "LINK:foo",
142	"broken/broken.go": "LINK:../nonexistent",
143	},
144	func(path string, typ os.FileMode) error {
145	return nil
146	},
147	map[string]os.FileMode{
148	"": os.ModeDir,
149	"/src": os.ModeDir,
150	"/src/bar": os.ModeDir,
151	"/src/bar/bar.go": os.ModeSymlink,
152	"/src/foo": os.ModeDir,
153	"/src/foo/foo.go": 0,
154	"/src/symdir": os.ModeSymlink,
155	"/src/broken": os.ModeDir,
156	"/src/broken/broken.go": os.ModeSymlink,
157	})
158	}
159
160	func TestFastWalk_SkipDir(t *testing.T) {
161	testFastWalk(t, map[string]string{
162	"foo/foo.go": "one",
163	"bar/bar.go": "two",
164	"skip/skip.go": "skip",
165	},
166	func(path string, typ os.FileMode) error {
167	if typ == os.ModeDir && strings.HasSuffix(path, "skip") {
168	return filepath.SkipDir
169	}
170	return nil
171	},
172	map[string]os.FileMode{
173	"": os.ModeDir,
174	"/src": os.ModeDir,
175	"/src/bar": os.ModeDir,
176	"/src/bar/bar.go": 0,
177	"/src/foo": os.ModeDir,
178	"/src/foo/foo.go": 0,
179	"/src/skip": os.ModeDir,
180	})
181	}
182
183	func TestFastWalk_SkipFiles(t *testing.T) {
184	// Directory iteration order is undefined, so there's no way to know
185	// which file to expect until the walk happens. Rather than mess
186	// with the test infrastructure, just mutate want.
187	var mu sync.Mutex
188	want := map[string]os.FileMode{
189	"": os.ModeDir,
190	"/src": os.ModeDir,
191	"/src/zzz": os.ModeDir,
192	"/src/zzz/c.go": 0,
193	}
194
195	testFastWalk(t, map[string]string{
196	"a_skipfiles.go": "a",
197	"b_skipfiles.go": "b",
198	"zzz/c.go": "c",
199	},
200	func(path string, typ os.FileMode) error {
201	if strings.HasSuffix(path, "_skipfiles.go") {
202	mu.Lock()
203	defer mu.Unlock()
204	want["/src/"+filepath.Base(path)] = 0
205	return fastwalk.ErrSkipFiles
206	}
207	return nil
208	},
209	want)
210	if len(want) != 5 {
211	t.Errorf("saw too many files: wanted 5, got %v (%v)", len(want), want)
212	}
213	}
214
215	func TestFastWalk_TraverseSymlink(t *testing.T) {
216	testFastWalk(t, map[string]string{
217	"foo/foo.go": "one",
218	"bar/bar.go": "two",
219	"skip/skip.go": "skip",
220	"symdir": "LINK:foo",
221	},
222	func(path string, typ os.FileMode) error {
223	if typ == os.ModeSymlink {
224	return fastwalk.ErrTraverseLink
225	}
226	return nil
227	},
228	map[string]os.FileMode{
229	"": os.ModeDir,
230	"/src": os.ModeDir,
231	"/src/bar": os.ModeDir,
232	"/src/bar/bar.go": 0,
233	"/src/foo": os.ModeDir,
234	"/src/foo/foo.go": 0,
235	"/src/skip": os.ModeDir,
236	"/src/skip/skip.go": 0,
237	"/src/symdir": os.ModeSymlink,
238	"/src/symdir/foo.go": 0,
239	})
240	}
241
242	var benchDir = flag.String("benchdir", runtime.GOROOT(), "The directory to scan for BenchmarkFastWalk")
243
244	func BenchmarkFastWalk(b *testing.B) {
245	b.ReportAllocs()
246	for i := 0; i < b.N; i++ {
247	err := fastwalk.Walk(*benchDir, func(path string, typ os.FileMode) error { return nil })
248	if err != nil {
249	b.Fatal(err)
250	}
251	}
252	}
253