rewrote config file path search (#219)

added comment to clarify coding choices

added package xdg to vendor folder

rewrote config file path search

Co-authored-by: crapStone <crapstone01@gmail.com>
Reviewed-on: https://gitea.com/gitea/tea/pulls/219
Reviewed-by: 6543 <6543@noreply.gitea.io>
Reviewed-by: Norwin <noerw@noreply.gitea.io>

vendor/github.com/adrg/xdg/utils.go

@@ -0,0 +1,126 @@
+package xdg
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+func homeDir() string {
+	homeEnv := "HOME"
+	switch runtime.GOOS {
+	case "windows":
+		homeEnv = "USERPROFILE"
+	case "plan9":
+		homeEnv = "home"
+	}
+
+	if home := os.Getenv(homeEnv); home != "" {
+		return home
+	}
+
+	switch runtime.GOOS {
+	case "nacl":
+		return "/"
+	case "darwin":
+		if runtime.GOARCH == "arm" || runtime.GOARCH == "arm64" {
+			return "/"
+		}
+	}
+
+	return ""
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil || os.IsExist(err)
+}
+
+func expandPath(path, homeDir string) string {
+	if path == "" || homeDir == "" {
+		return path
+	}
+	if path[0] == '~' {
+		return filepath.Join(homeDir, path[1:])
+	}
+	if strings.HasPrefix(path, "$HOME") {
+		return filepath.Join(homeDir, path[5:])
+	}
+
+	return path
+}
+
+func createPath(name string, paths []string) (string, error) {
+	var searchedPaths []string
+	for _, p := range paths {
+		path := filepath.Join(p, name)
+		dir := filepath.Dir(path)
+
+		if exists(dir) {
+			return path, nil
+		}
+		if err := os.MkdirAll(dir, os.ModeDir|0700); err == nil {
+			return path, nil
+		}
+
+		searchedPaths = append(searchedPaths, dir)
+	}
+
+	return "", fmt.Errorf("could not create any of the following paths: %s",
+		strings.Join(searchedPaths, ", "))
+}
+
+func searchFile(name string, paths []string) (string, error) {
+	var searchedPaths []string
+	for _, p := range paths {
+		path := filepath.Join(p, name)
+		if exists(path) {
+			return path, nil
+		}
+
+		searchedPaths = append(searchedPaths, filepath.Dir(path))
+	}
+
+	return "", fmt.Errorf("could not locate `%s` in any of the following paths: %s",
+		filepath.Base(name), strings.Join(searchedPaths, ", "))
+}
+
+func xdgPath(name, defaultPath string) string {
+	dir := expandPath(os.Getenv(name), Home)
+	if dir != "" && filepath.IsAbs(dir) {
+		return dir
+	}
+
+	return defaultPath
+}
+
+func xdgPaths(name string, defaultPaths ...string) []string {
+	dirs := uniquePaths(filepath.SplitList(os.Getenv(name)))
+	if len(dirs) != 0 {
+		return dirs
+	}
+
+	return uniquePaths(defaultPaths)
+}
+
+func uniquePaths(paths []string) []string {
+	var uniq []string
+	registry := map[string]struct{}{}
+
+	for _, p := range paths {
+		dir := expandPath(p, Home)
+		if dir == "" || !filepath.IsAbs(dir) {
+			continue
+		}
+		if _, ok := registry[dir]; ok {
+			continue
+		}
+
+		registry[dir] = struct{}{}
+		uniq = append(uniq, dir)
+	}
+
+	return uniq
+}