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/base_dirs.go

@@ -0,0 +1,78 @@
+package xdg
+
+import "os"
+
+// XDG Base Directory environment variables.
+var (
+	envDataHome   = "XDG_DATA_HOME"
+	envDataDirs   = "XDG_DATA_DIRS"
+	envConfigHome = "XDG_CONFIG_HOME"
+	envConfigDirs = "XDG_CONFIG_DIRS"
+	envCacheHome  = "XDG_CACHE_HOME"
+	envRuntimeDir = "XDG_RUNTIME_DIR"
+)
+
+type baseDirectories struct {
+	dataHome   string
+	data       []string
+	configHome string
+	config     []string
+	cacheHome  string
+	runtime    string
+
+	// Non-standard directories.
+	fonts        []string
+	applications []string
+}
+
+func (bd baseDirectories) dataFile(relPath string) (string, error) {
+	return createPath(relPath, append([]string{bd.dataHome}, bd.data...))
+}
+
+func (bd baseDirectories) configFile(relPath string) (string, error) {
+	return createPath(relPath, append([]string{bd.configHome}, bd.config...))
+}
+
+func (bd baseDirectories) cacheFile(relPath string) (string, error) {
+	return createPath(relPath, []string{bd.cacheHome})
+}
+
+func (bd baseDirectories) runtimeFile(relPath string) (string, error) {
+	fi, err := os.Lstat(bd.runtime)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return createPath(relPath, []string{bd.runtime})
+		}
+		return "", err
+	}
+
+	if fi.IsDir() {
+		// The runtime directory must be owned by the user.
+		if err = os.Chown(bd.runtime, os.Getuid(), os.Getgid()); err != nil {
+			return "", err
+		}
+	} else {
+		// For security reasons, the runtime directory cannot be a symlink.
+		if err = os.Remove(bd.runtime); err != nil {
+			return "", err
+		}
+	}
+
+	return createPath(relPath, []string{bd.runtime})
+}
+
+func (bd baseDirectories) searchDataFile(relPath string) (string, error) {
+	return searchFile(relPath, append([]string{bd.dataHome}, bd.data...))
+}
+
+func (bd baseDirectories) searchConfigFile(relPath string) (string, error) {
+	return searchFile(relPath, append([]string{bd.configHome}, bd.config...))
+}
+
+func (bd baseDirectories) searchCacheFile(relPath string) (string, error) {
+	return searchFile(relPath, []string{bd.cacheHome})
+}
+
+func (bd baseDirectories) searchRuntimeFile(relPath string) (string, error) {
+	return searchFile(relPath, []string{bd.runtime})
+}