Implement preliminary support for XDG Base Directory Specification.

See http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html.

This feature was requested for a long time (feature requests #1950978 and #2289481).
For now, it is disabled since it breaks compatibility with previous versions.
To be able to test it, you have to enable it by defining USE_XDG to 1 in main.h.

geeqierc and other conf files are going to:
$XDG_CONFIG_HOME/geeqie/ (default to $HOME/.config/geeqie/).

metadata and thumbnails cache (if std is not used) are going to:
$XDG_CACHE_HOME/geeqie/metadata/ (default to $HOME/.cache/geeqie/metadata/)
and $XDG_CACHE_HOME/geeqie/thumbnails/ (default to $HOME/.cache/geeqie/thumbnails/)

collections are going to:
$XDG_DATA_HOME/geeqie/collections/ (default to $HOME/.local/share/geeqie/collections/)


Please test and report any issue.

src/cache.c

@@ -767,7 +767,15 @@ const gchar *get_thumbnails_cache_dir(void)
 
 	if (thumbnails_cache_dir) return thumbnails_cache_dir;
 
-	thumbnails_cache_dir = g_build_filename(get_rc_dir(), GQ_CACHE_THUMB, NULL);
+	if (USE_XDG)
+		{
+		thumbnails_cache_dir = g_build_filename(xdg_cache_home_get(), GQ_APPNAME_LC, GQ_CACHE_THUMB, NULL);
+		}
+	else
+		{
+		thumbnails_cache_dir = g_build_filename(get_rc_dir(), GQ_CACHE_THUMB, NULL);
+		}
+
 	return thumbnails_cache_dir;
 }
 
@@ -777,7 +785,15 @@ const gchar *get_metadata_cache_dir(void)
 
 	if (metadata_cache_dir) return metadata_cache_dir;
 
-	metadata_cache_dir = g_build_filename(get_rc_dir(), GQ_CACHE_METADATA, NULL);
+	if (USE_XDG)
+		{
+		metadata_cache_dir = g_build_filename(xdg_cache_home_get(), GQ_APPNAME_LC, GQ_CACHE_METADATA, NULL);
+		}
+	else
+		{
+		metadata_cache_dir = g_build_filename(get_rc_dir(), GQ_CACHE_METADATA, NULL);
+		}
+
 	return metadata_cache_dir;
 }
 

src/main.h

@@ -64,6 +64,8 @@
  *----------------------------------------------------------------------------
  */
 
+#define USE_XDG 0
+
 #define GQ_APPNAME "Geeqie"
 #define GQ_APPNAME_LC "geeqie"
 #define GQ_WEBSITE "geeqie.sourceforge.net"

src/ui_fileops.c

@@ -186,14 +186,66 @@ const gchar *homedir(void)
 	return home;
 }
 
+static gchar *xdg_dir_get(const gchar *key, const gchar *fallback)
+{
+	gchar *dir = getenv(key);
+
+	if (!dir || dir[0] == '\0')
+		{
+    		return g_build_filename(homedir(), fallback, NULL);
+    		}
+
+	return path_to_utf8(dir);
+}
+
+const gchar *xdg_data_home_get(void)
+{
+	static const gchar *xdg_data_home = NULL;
+
+	if (xdg_data_home) return xdg_data_home;
+
+	xdg_data_home = xdg_dir_get("XDG_DATA_HOME", ".local/share");
+
+	return xdg_data_home;
+}
+
+const gchar *xdg_config_home_get(void)
+{
+	static const gchar *xdg_config_home = NULL;
+
+	if (xdg_config_home) return xdg_config_home;
+
+	xdg_config_home = xdg_dir_get("XDG_CONFIG_HOME", ".config");
+
+	return xdg_config_home;
+}
+
+const gchar *xdg_cache_home_get(void)
+{
+	static const gchar *xdg_cache_home = NULL;
+
+	if (xdg_cache_home) return xdg_cache_home;
+
+	xdg_cache_home = xdg_dir_get("XDG_CACHE_HOME", ".cache");
+
+	return xdg_cache_home;
+}
+
 const gchar *get_rc_dir(void)
 {
 	static gchar *rc_dir = NULL;
 
 	if (rc_dir) return rc_dir;
 
-	rc_dir = g_build_filename(homedir(), GQ_RC_DIR, NULL);
-
+	if (USE_XDG)
+		{
+		rc_dir = g_build_filename(xdg_config_home_get(), GQ_APPNAME_LC, NULL);
+		}
+	else
+		{
+		rc_dir = g_build_filename(homedir(), GQ_RC_DIR, NULL);
+		}
+
 	return rc_dir;
 }
 
@@ -203,8 +255,15 @@ const gchar *get_collections_dir(void)
 
 	if (collections_dir) return collections_dir;
 
-	collections_dir = g_build_filename(get_rc_dir(), GQ_COLLECTIONS_DIR, NULL);
-
+	if (USE_XDG)
+		{
+		collections_dir = g_build_filename(xdg_data_home_get(), GQ_APPNAME_LC, GQ_COLLECTIONS_DIR, NULL);
+		}
+	else
+		{
+		collections_dir = g_build_filename(get_rc_dir(), GQ_COLLECTIONS_DIR, NULL);
+		}
+
 	return collections_dir;
 }
 
@@ -213,9 +272,16 @@ const gchar *get_trash_dir(void)
 	static gchar *trash_dir = NULL;
 
 	if (trash_dir) return trash_dir;
-
-	trash_dir = g_build_filename(get_rc_dir(), GQ_TRASH_DIR, NULL);
 
+	if (USE_XDG)
+		{
+		trash_dir = g_build_filename(xdg_data_home_get(), GQ_APPNAME_LC, GQ_TRASH_DIR, NULL);
+		}
+	else
+		{
+		trash_dir = g_build_filename(get_rc_dir(), GQ_TRASH_DIR, NULL);
+	}
+
 	return trash_dir;
 }
 

src/ui_fileops.h

@@ -34,6 +34,9 @@ void print_term(const gchar *text_utf8);
 gchar *path_to_utf8(const gchar *path);
 gchar *path_from_utf8(const gchar *path);
 
+const gchar *xdg_data_home_get(void);
+const gchar *xdg_config_home_get(void);
+const gchar *xdg_cache_home_get(void);
 const gchar *homedir(void);
 const gchar *get_rc_dir(void);
 const gchar *get_collections_dir(void);