1// Copyright 2019 The Hugo Authors. All rights reserved.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6// http://www.apache.org/licenses/LICENSE-2.0
7//
8// Unless required by applicable law or agreed to in writing, software
9// distributed under the License is distributed on an "AS IS" BASIS,
10// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11// See the License for the specific language governing permissions and
12// limitations under the License.
13
14package hugofs
15
16import (
17	"fmt"
18	"os"
19	"regexp"
20	"runtime"
21
22	"github.com/gohugoio/hugo/common/types"
23
24	"github.com/spf13/afero"
25)
26
27// Make sure we don't accidentally use this in the real Hugo.
28var _ types.DevMarker = (*stacktracerFs)(nil)
29
30// NewStacktracerFs wraps the given fs printing stack traces for file creates
31// matching the given regexp pattern.
32func NewStacktracerFs(fs afero.Fs, pattern string) afero.Fs {
33	return &stacktracerFs{Fs: fs, re: regexp.MustCompile(pattern)}
34}
35
36// stacktracerFs can be used in hard-to-debug development situations where
37// you get some input you don't understand where comes from.
38type stacktracerFs struct {
39	afero.Fs
40
41	// Will print stacktrace for every file creates matching this pattern.
42	re *regexp.Regexp
43}
44
45func (fs *stacktracerFs) DevOnly() {
46}
47
48func (fs *stacktracerFs) onCreate(filename string) {
49	if fs.re.MatchString(filename) {
50		trace := make([]byte, 1500)
51		runtime.Stack(trace, true)
52		fmt.Printf("\n===========\n%q:\n%s\n", filename, trace)
53	}
54}
55
56func (fs *stacktracerFs) Create(name string) (afero.File, error) {
57	f, err := fs.Fs.Create(name)
58	if err == nil {
59		fs.onCreate(name)
60	}
61	return f, err
62}
63
64func (fs *stacktracerFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
65	f, err := fs.Fs.OpenFile(name, flag, perm)
66	if err == nil && isWrite(flag) {
67		fs.onCreate(name)
68	}
69	return f, err
70}
71