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eth-peth-p
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feat: Add FileCopyMethod option / API
This will be used so we can have multiple implementations for copying a regular file. Currently, there is just CopyBytes, which is the old fcopy code. The FileCopyMethod struct is a struct with an un-exported member. This is done to make the type opaque so the user can't make their own copy function. There are still design questions left about passing around the `Options` struct and `os.FileInfo`, so I opted to do this so that can be figured out later. The type can be made into `type FileCopyMethod func(...)` later, and it won't be a breaking change. Or, instead, a `UserCopy(func (src, dest string) error) FileCopyMethod` function can be added.
1 parent 2f93b8f commit 9205813

3 files changed

Lines changed: 109 additions & 67 deletions

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‎copy.go‎

Lines changed: 2 additions & 67 deletions
Original file line numberDiff line numberDiff line change
@@ -86,73 +86,8 @@ func copyNextOrSkip(src, dest string, info os.FileInfo, opt Options) error {
8686
// with considering existence of parent directory
8787
// and file permission.
8888
func fcopy(src, dest string, info os.FileInfo, opt Options) (err error) {
89-
90-
var readcloser io.ReadCloser
91-
if opt.FS != nil {
92-
readcloser, err = opt.FS.Open(src)
93-
} else {
94-
readcloser, err = os.Open(src)
95-
}
96-
if err != nil {
97-
if os.IsNotExist(err) {
98-
return nil
99-
}
100-
return
101-
}
102-
defer fclose(readcloser, &err)
103-
104-
if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
105-
return
106-
}
107-
108-
f, err := os.Create(dest)
109-
if err != nil {
110-
return
111-
}
112-
defer fclose(f, &err)
113-
114-
chmodfunc, err := opt.PermissionControl(info, dest)
115-
if err != nil {
116-
return err
117-
}
118-
chmodfunc(&err)
119-
120-
var buf []byte = nil
121-
var w io.Writer = f
122-
var r io.Reader = readcloser
123-
124-
if opt.WrapReader != nil {
125-
r = opt.WrapReader(r)
126-
}
127-
128-
if opt.CopyBufferSize != 0 {
129-
buf = make([]byte, opt.CopyBufferSize)
130-
// Disable using `ReadFrom` by io.CopyBuffer.
131-
// See https://github.com/otiai10/copy/pull/60#discussion_r627320811 for more details.
132-
w = struct{ io.Writer }{f}
133-
// r = struct{ io.Reader }{s}
134-
}
135-
136-
if _, err = io.CopyBuffer(w, r, buf); err != nil {
137-
return err
138-
}
139-
140-
if opt.Sync {
141-
err = f.Sync()
142-
}
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144-
if opt.PreserveOwner {
145-
if err := preserveOwner(src, dest, info); err != nil {
146-
return err
147-
}
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}
149-
if opt.PreserveTimes {
150-
if err := preserveTimes(info, dest); err != nil {
151-
return err
152-
}
153-
}
154-
155-
return
89+
err, _ = opt.FileCopyMethod.fcopy(src, dest, info, opt)
90+
return err
15691
}
15792

15893
// dcopy is for a directory,

‎copy_methods.go‎

Lines changed: 88 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,88 @@
1+
package copy
2+
3+
import (
4+
"errors"
5+
"io"
6+
"os"
7+
"path/filepath"
8+
)
9+
10+
// ErrUnsupportedCopyMethod is returned when the FileCopyMethod specified in
11+
// Options is not supported.
12+
var ErrUnsupportedCopyMethod = errors.New(
13+
"copy method not supported",
14+
)
15+
16+
// CopyBytes copies the file contents by reading the source file into a buffer,
17+
// then writing the buffer back to the destination file.
18+
var CopyBytes = FileCopyMethod{
19+
fcopy: func(src, dest string, info os.FileInfo, opt Options) (err error, skipFile bool) {
20+
21+
var readcloser io.ReadCloser
22+
if opt.FS != nil {
23+
readcloser, err = opt.FS.Open(src)
24+
} else {
25+
readcloser, err = os.Open(src)
26+
}
27+
if err != nil {
28+
if os.IsNotExist(err) {
29+
return nil, true
30+
}
31+
return
32+
}
33+
defer fclose(readcloser, &err)
34+
35+
if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
36+
return
37+
}
38+
39+
f, err := os.Create(dest)
40+
if err != nil {
41+
return
42+
}
43+
defer fclose(f, &err)
44+
45+
chmodfunc, err := opt.PermissionControl(info, dest)
46+
if err != nil {
47+
return err, false
48+
}
49+
chmodfunc(&err)
50+
51+
var buf []byte = nil
52+
var w io.Writer = f
53+
var r io.Reader = readcloser
54+
55+
if opt.WrapReader != nil {
56+
r = opt.WrapReader(r)
57+
}
58+
59+
if opt.CopyBufferSize != 0 {
60+
buf = make([]byte, opt.CopyBufferSize)
61+
// Disable using `ReadFrom` by io.CopyBuffer.
62+
// See https://github.com/otiai10/copy/pull/60#discussion_r627320811 for more details.
63+
w = struct{ io.Writer }{f}
64+
// r = struct{ io.Reader }{s}
65+
}
66+
67+
if _, err = io.CopyBuffer(w, r, buf); err != nil {
68+
return err, false
69+
}
70+
71+
if opt.Sync {
72+
err = f.Sync()
73+
}
74+
75+
if opt.PreserveOwner {
76+
if err := preserveOwner(src, dest, info); err != nil {
77+
return err, false
78+
}
79+
}
80+
if opt.PreserveTimes {
81+
if err := preserveTimes(info, dest); err != nil {
82+
return err, false
83+
}
84+
}
85+
86+
return
87+
},
88+
}

‎options.go‎

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -27,6 +27,16 @@ type Options struct {
2727
// RenameDestination can specify the destination file or dir name if needed to rename.
2828
RenameDestination func(src, dest string) (string, error)
2929

30+
// FileCopyMethod specifies the method by which a regular file is copied.
31+
// The default is CopyBytes.
32+
//
33+
// Available implementations:
34+
// - CopyBytes (best compatibility)
35+
//
36+
// Some implementations may not be supported on the target GOOS, or on
37+
// the user's filesystem. When these fail, an error will be returned.
38+
FileCopyMethod FileCopyMethod
39+
3040
// Specials includes special files to be copied. default false.
3141
Specials bool
3242

@@ -119,6 +129,11 @@ const (
119129
Untouchable
120130
)
121131

132+
// FileCopyMethod represents one of the ways that a regular file can be copied.
133+
type FileCopyMethod struct {
134+
fcopy func(src, dest string, info os.FileInfo, opt Options) (err error, skipFile bool)
135+
}
136+
122137
// getDefaultOptions provides default options,
123138
// which would be modified by usage-side.
124139
func getDefaultOptions(src, dest string) Options {
@@ -134,6 +149,7 @@ func getDefaultOptions(src, dest string) Options {
134149
Sync: false, // Do not sync
135150
Specials: false, // Do not copy special files
136151
PreserveTimes: false, // Do not preserve the modification time
152+
FileCopyMethod: CopyBytes, // Copy by bytes
137153
CopyBufferSize: 0, // Do not specify, use default bufsize (32*1024)
138154
WrapReader: nil, // Do not wrap src files, use them as they are.
139155
intent: intent{src, dest, nil, nil},
@@ -158,6 +174,9 @@ func assureOptions(src, dest string, opts ...Options) Options {
158174
} else if opts[0].PermissionControl == nil {
159175
opts[0].PermissionControl = PerservePermission
160176
}
177+
if opts[0].FileCopyMethod.fcopy == nil {
178+
opts[0].FileCopyMethod = defopt.FileCopyMethod
179+
}
161180
opts[0].intent.src = defopt.intent.src
162181
opts[0].intent.dest = defopt.intent.dest
163182
return opts[0]

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