Expose public/ API as submodule (#23345)

* model -> public/model

* plugin -> public/plugin

* public/model/utils -> public/utils

* platform/shared/mlog -> public/shared/mlog

* platform/shared/i18n -> public/shared/i18n

* platform/shared/markdown -> public/shared/markdown

* platform/services/timezones -> public/shared/timezones

* channels/einterfaces -> einterfaces

* expose public/ submodule

* go mod tidy

* .github: cache-dependency-path, setup-go-work

* modules-tidy for public/ too

* remove old gomodtidy

server/public/utils/file.go

@@ -0,0 +1,118 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+)
+
+// CopyFile will copy a file from src path to dst path.
+// Overwrites any existing files at dst.
+// Permissions are copied from file at src to the new file at dst.
+func CopyFile(src, dst string) (err error) {
+	in, err := os.Open(src)
+	if err != nil {
+		return
+	}
+	defer in.Close()
+
+	if err = os.MkdirAll(filepath.Dir(dst), os.ModePerm); err != nil {
+		return
+	}
+	out, err := os.Create(dst)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if e := out.Close(); e != nil {
+			err = e
+		}
+	}()
+
+	_, err = io.Copy(out, in)
+	if err != nil {
+		return
+	}
+
+	err = out.Sync()
+	if err != nil {
+		return
+	}
+
+	stat, err := os.Stat(src)
+	if err != nil {
+		return
+	}
+	err = os.Chmod(dst, stat.Mode())
+	if err != nil {
+		return
+	}
+
+	return
+}
+
+// CopyDir will copy a directory and all contained files and directories.
+// src must exist and dst must not exist.
+// Permissions are preserved when possible. Symlinks are skipped.
+func CopyDir(src string, dst string) (err error) {
+	src = filepath.Clean(src)
+	dst = filepath.Clean(dst)
+
+	stat, err := os.Stat(src)
+	if err != nil {
+		return
+	}
+	if !stat.IsDir() {
+		return fmt.Errorf("source must be a directory")
+	}
+
+	_, err = os.Stat(dst)
+	if err != nil && !os.IsNotExist(err) {
+		return
+	}
+	if err == nil {
+		return fmt.Errorf("destination already exists")
+	}
+
+	err = os.MkdirAll(dst, stat.Mode())
+	if err != nil {
+		return
+	}
+
+	items, err := os.ReadDir(src)
+	if err != nil {
+		return
+	}
+
+	for _, item := range items {
+		srcPath := filepath.Join(src, item.Name())
+		dstPath := filepath.Join(dst, item.Name())
+
+		if item.IsDir() {
+			err = CopyDir(srcPath, dstPath)
+			if err != nil {
+				return
+			}
+		} else {
+			info, ierr := item.Info()
+			if ierr != nil {
+				continue
+			}
+
+			if info.Mode()&os.ModeSymlink != 0 {
+				continue
+			}
+
+			err = CopyFile(srcPath, dstPath)
+			if err != nil {
+				return
+			}
+		}
+	}
+
+	return
+}