Use standardized data directories on linux

README.md

@@ -72,11 +72,11 @@ You can download the latest stable from [Releases](https://github.com/sourcegit-
 
 This software creates a folder, which is platform-dependent, to store user settings, downloaded avatars and crash logs.
 
-| OS      | PATH                                      |
-|---------|-------------------------------------------|
-| Windows | `%APPDATA%\SourceGit`                     |
-| Linux   | `~/.sourcegit`                            |
-| macOS   | `~/Library/Application Support/SourceGit` |
+| OS      | PATH                                             |
+|---------|--------------------------------------------------|
+| Windows | `%APPDATA%\SourceGit`                            |
+| Linux   | `~/.local/share/SourceGit`, `~/.cache/SourceGit` |
+| macOS   | `~/Library/Application Support/SourceGit`        |
 
 > [!TIP]
 > * You can open this data storage directory from the main menu `Open Data Storage Directory`.

src/App.axaml.cs

@@ -24,6 +24,7 @@ public partial class App : Application
         public static void Main(string[] args)
         {
             Native.OS.SetupDataDir();
+            Native.OS.SetupCacheDir();
 
             AppDomain.CurrentDomain.UnhandledException += (_, e) =>
             {

src/Models/AvatarManager.cs

@@ -44,9 +44,7 @@ public static AvatarManager Instance
 
         public void Start()
         {
-            _storePath = Path.Combine(Native.OS.DataDir, "avatars");
-            if (!Directory.Exists(_storePath))
-                Directory.CreateDirectory(_storePath);
+            _storePath = Path.Combine(Native.OS.CacheDir, "avatars");
 
             LoadDefaultAvatar("noreply@github.com", "github.png");
             LoadDefaultAvatar("unrealbot@epicgames.com", "unreal.png");
@@ -87,6 +85,9 @@ public void Start()
                         url = $"https://avatars.githubusercontent.com/{githubUser}";
                     }
 
+                    if (!Directory.Exists(_storePath))
+                        Directory.CreateDirectory(_storePath);
+
                     var localFile = Path.Combine(_storePath, md5);
                     Bitmap img = null;
                     try

src/Native/Linux.cs

@@ -46,11 +46,50 @@ public string GetDataDir()
                     return portableDir;
             }
 
-            // Runtime data dir: ~/.sourcegit
-            var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
-            return Path.Combine(home, ".sourcegit");
+            var homeDir = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+            var dataDir = GetXdgDir("XDG_DATA_HOME");
+
+            if (!Directory.Exists(dataDir)) {
+                foreach (var oldDataDir in new[] { ".SourceGit", ".config/SourceGit" }) {
+                    if (!Directory.Exists(Path.Combine(homeDir, oldDataDir))) continue;
+
+                    Directory.Delete(Path.Combine(oldDataDir, "avatars"), true);
+                    Directory.Move(oldDataDir, dataDir!);
+                    break;
+                }
+            }
+
+            return GetXdgDir("XDG_DATA_HOME");
         }
 
+        public string GetCacheDir()
+        {
+
+            return GetXdgDir("XDG_CACHE_HOME");
+        }
+
+        // Directories according to the XDG user directory standard
+        // https://specifications.freedesktop.org/basedir/latest/
+        private static string GetXdgDir(string name)
+        {
+            string fallback;
+
+            switch(name)
+            {
+                default:
+                case "XDG_DATA_HOME": fallback = ".local/share/SourceGit"; break;
+                case "XDG_CONFIG_HOME": fallback = ".config/SourceGit"; break;
+                case "XDG_CACHE_HOME": fallback = ".cache/SourceGit"; break;
+            }
+
+            var home = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+            string dir = Environment.GetEnvironmentVariable(name);
+            if (dir == null || !Path.IsPathRooted(dir))
+                dir = Path.Combine(home, fallback);
+
+            return dir;
+        }
+
         public string FindGitExecutable()
         {
             return FindExecutable("git");

src/Native/MacOS.cs

@@ -54,6 +54,11 @@ public string GetDataDir()
                 "SourceGit");
         }
 
+        public string GetCacheDir()
+        {
+            return GetDataDir();
+        }
+
         public string FindGitExecutable()
         {
             var gitPathVariants = new List<string>() {

src/Native/OS.cs

@@ -20,6 +20,7 @@ public interface IBackend
             void SetupWindow(Window window);
 
             string GetDataDir();
+            string GetCacheDir();
             string FindGitExecutable();
             string FindTerminal(Models.ShellOrTerminal shell);
             List<Models.ExternalTool> FindExternalTools();
@@ -35,6 +36,12 @@ public static string DataDir
             get;
             private set;
         } = string.Empty;
+
+        public static string CacheDir
+        {
+            get;
+            private set;
+        } = string.Empty;
 
         public static string GitExecutable
         {
@@ -139,6 +146,12 @@ public static void SetupDataDir()
             if (!Directory.Exists(DataDir))
                 Directory.CreateDirectory(DataDir);
         }
+
+        public static void SetupCacheDir()
+        {
+            // cache directory is created when placing data in it
+            return;
+        }
 
         public static void SetupApp(AppBuilder builder)
         {

src/Native/Windows.cs

@@ -54,6 +54,11 @@ public string GetDataDir()
                 "SourceGit");
         }
 
+        public string GetCacheDir()
+        {
+            return GetDataDir();
+        }
+
         public string FindGitExecutable()
         {
             var reg = Microsoft.Win32.RegistryKey.OpenBaseKey(