Revert "CopyMethod" since it's not ready

Revert "ci: Allow triggering Go workflow manually"
This reverts commit f530620.
Revert "refactor: Split common code out of CopyBytes"
This reverts commit b4dd789.
Revert "feat: Add FileCopyMethod option / API"
This reverts commit 9205813.

.github/workflows/go.yml

@@ -5,7 +5,6 @@ on:
     branches: [ main, develop ]
   pull_request:
     branches: [ main, develop ]
-  workflow_dispatch:
 
 jobs:
 

copy.go

@@ -86,38 +86,66 @@ func copyNextOrSkip(src, dest string, info os.FileInfo, opt Options) error {
 // with considering existence of parent directory
 // and file permission.
 func fcopy(src, dest string, info os.FileInfo, opt Options) (err error) {
-	if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
+
+	var readcloser io.ReadCloser
+	if opt.FS != nil {
+		readcloser, err = opt.FS.Open(src)
+	} else {
+		readcloser, err = os.Open(src)
+	}
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
 		return
 	}
+	defer fclose(readcloser, &err)
 
-	// Use FileCopyMethod to do copy.
-	err, skipFile := opt.FileCopyMethod.fcopy(src, dest, info, opt)
-	if skipFile {
-		return nil
+	if err = os.MkdirAll(filepath.Dir(dest), os.ModePerm); err != nil {
+		return
 	}
 
+	f, err := os.Create(dest)
 	if err != nil {
-		return err
+		return
 	}
+	defer fclose(f, &err)
 
-	// Change file permissions.
 	chmodfunc, err := opt.PermissionControl(info, dest)
 	if err != nil {
 		return err
 	}
-
 	chmodfunc(&err)
-	if err != nil {
+
+	var buf []byte = nil
+	var w io.Writer = f
+	var r io.Reader = readcloser
+
+	if opt.WrapReader != nil {
+		r = opt.WrapReader(r)
+	}
+
+	if opt.CopyBufferSize != 0 {
+		buf = make([]byte, opt.CopyBufferSize)
+		// Disable using `ReadFrom` by io.CopyBuffer.
+		// See https://github.com/otiai10/copy/pull/60#discussion_r627320811 for more details.
+		w = struct{ io.Writer }{f}
+		// r = struct{ io.Reader }{s}
+	}
+
+	if _, err = io.CopyBuffer(w, r, buf); err != nil {
 		return err
 	}
 
-	// Preserve file ownership and times.
+	if opt.Sync {
+		err = f.Sync()
+	}
+
 	if opt.PreserveOwner {
 		if err := preserveOwner(src, dest, info); err != nil {
 			return err
 		}
 	}
-
 	if opt.PreserveTimes {
 		if err := preserveTimes(info, dest); err != nil {
 			return err

options.go

@@ -27,16 +27,6 @@ type Options struct {
 	// RenameDestination can specify the destination file or dir name if needed to rename.
 	RenameDestination func(src, dest string) (string, error)
 
-	// FileCopyMethod specifies the method by which a regular file is copied.
-	// The default is CopyBytes.
-	//
-	// Available implementations:
-	//    - CopyBytes (best compatibility)
-	//
-	// Some implementations may not be supported on the target GOOS, or on
-	// the user's filesystem. When these fail, an error will be returned.
-	FileCopyMethod FileCopyMethod
-
 	// Specials includes special files to be copied. default false.
 	Specials bool
 
@@ -129,11 +119,6 @@ const (
 	Untouchable
 )
 
-// FileCopyMethod represents one of the ways that a regular file can be copied.
-type FileCopyMethod struct {
-	fcopy func(src, dest string, info os.FileInfo, opt Options) (err error, skipFile bool)
-}
-
 // getDefaultOptions provides default options,
 // which would be modified by usage-side.
 func getDefaultOptions(src, dest string) Options {
@@ -149,7 +134,6 @@ func getDefaultOptions(src, dest string) Options {
 		Sync:              false,              // Do not sync
 		Specials:          false,              // Do not copy special files
 		PreserveTimes:     false,              // Do not preserve the modification time
-		FileCopyMethod:    CopyBytes,          // Copy by bytes
 		CopyBufferSize:    0,                  // Do not specify, use default bufsize (32*1024)
 		WrapReader:        nil,                // Do not wrap src files, use them as they are.
 		intent:            intent{src, dest, nil, nil},
@@ -174,9 +158,6 @@ func assureOptions(src, dest string, opts ...Options) Options {
 	} else if opts[0].PermissionControl == nil {
 		opts[0].PermissionControl = PerservePermission
 	}
-	if opts[0].FileCopyMethod.fcopy == nil {
-		opts[0].FileCopyMethod = defopt.FileCopyMethod
-	}
 	opts[0].intent.src = defopt.intent.src
 	opts[0].intent.dest = defopt.intent.dest
 	return opts[0]