Use XDG directories, and respect corresponding environment vars

config/config.go

@@ -8,6 +8,29 @@ import "strconv"
 import "image/color"
 import "path/filepath"
 
+
+// when making changes to this file, look at
+// https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
+
+// Error represents an error that can be returned by functions or methods in
+// this module.
+type Error int
+
+const (
+	// ErrorIllegalName is thrown when an application name contains illegal
+	// characters such as a slash.
+	ErrorIllegalName Error = iota
+)
+
+func (err Error) Error () (description string) {
+	switch err {
+	case ErrorIllegalName:
+		description = "name contains illegal characters"
+	}
+
+	return
+}
+
 // Type represents the data type of a configuration parameter.
 type Type int
 
@@ -41,9 +64,15 @@ type Config struct {
 	Parameters map[string] any
 }
 
-// Load loads and parses the files /etc/<name>/<name>.conf and
+// Load loads and parses the files /etc/xdg/<name>/<name>.conf and
-// <home>/.config/<name>/<name>.conf.
+// <home>/.config/<name>/<name>.conf, unless the corresponding XDG environment
+// variables are set - then it uses those.
 func (config *Config) Load (name string) (err error) {
+	if strings.ContainsAny(name, "/\\|:.%") {
+		err = ErrorIllegalName
+		return
+	}
+
 	if config.LegalParameters == nil {
 		config.LegalParameters = make(map[string] Type)
 	}
@@ -52,11 +81,27 @@ func (config *Config) Load (name string) (err error) {
 		config.Parameters = make(map[string] any)
 	}
 	
-	config.loadFile("/etc/" + name + "/" + name + ".conf")
 	var homeDirectory string
 	homeDirectory, err = os.UserHomeDir()
 	if err != nil { return }
-	config.loadFile(filepath.Join(homeDirectory, "/.config/" + name + "/" + name + ".conf"))
+
+	configHome := os.Getenv("XDG_CONFIG_HOME")
+	if configHome == "" {
+		configHome = filepath.Join(homeDirectory, "/.config/")
+	}
+
+	configDirsString := os.Getenv("XDG_CONFIG_DIRS")
+	if configDirsString == "" {
+		configDirsString = "/etc/xdg/"
+	}
+
+	configDirs := strings.Split(configDirsString, ":")
+	configDirs = append(configDirs, configHome)
+
+	for _, directory := range configDirs {
+		config.loadFile(filepath.Join(directory, name, name + ".conf"))
+	}
+
 	return
 }