main: make ~/.ctags.d as the default element for the optlib path list

Signed-off-by: Masatake YAMATO <[email protected]>

Author: masatake

docs/man/ctags.1.rst

@@ -830,7 +830,7 @@ Option File Options
 
 ``--optlib-dir=[+]<directory>``
 	Add an optlib *<directory>* to or reset the optlib path list.
-	By default, the optlib path list is empty.
+	See "`Default optlib path list`_" about the default elements for optlib path list.
 
 optlib Options
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2203,6 +2203,19 @@ Preloading option files
 
 	``*.ctags`` files in a directory are loaded in alphabetical order.
 
+Default optlib path list
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+``$XDG_CONFIG_HOME/ctags``, or ``$HOME/.config/ctags`` if
+``$XDG_CONFIG_HOME`` is not defined
+(on other than MS Windows)
+
+``$HOME/.ctags.d``
+
+``$HOMEDRIVE$HOMEPATH/ctags.d`` (on MS Windows only)
+
+	These directories are parts of the optlib path list by default.
+	See "`Option File Options`_" about the optlib path list.
 
 SEE ALSO
 --------

main/options.c

@@ -3808,14 +3808,47 @@ extern void readOptionConfiguration (void)
 		parseConfigurationFileOptions ();
 }
 
+static stringList* optlibPathListNew(struct preloadPathElt *pathList)
+{
+	stringList * appended = stringListNew ();
+
+	for (size_t i = 0; pathList[i].path != NULL || pathList[i].makePath != NULL; ++i)
+	{
+		struct preloadPathElt *elt = pathList + i;
+		preloadMakePathFunc maker = elt->makePath;
+		const char *path = elt->path;
+
+		if (!elt->isDirectory)
+			continue;
+
+		if (elt->stage == OptionLoadingStageCurrentDir)
+			continue;
+
+		if (maker)
+			path = maker(elt->path, elt->extra);
+
+		if (path == NULL)
+			continue;
+
+		vString *vpath;
+		if (path == elt->path)
+			vpath = vStringNewInit (path);
+		else
+			vpath = vStringNewOwn ((char *)path);
+		stringListAdd(appended, vpath);
+	}
+
+	return appended;
+}
+
 /*
 *   Option initialization
 */
 
 extern void initOptions (void)
 {
 	OptionFiles = stringListNew ();
-	OptlibPathList = stringListNew ();
+	OptlibPathList = optlibPathListNew (preload_path_list);
 
 	verbose ("Setting option defaults\n");
 	installHeaderListDefaults ();

man/ctags.1.rst.in

@@ -830,7 +830,7 @@ Option File Options
 
 ``--optlib-dir=[+]<directory>``
 	Add an optlib *<directory>* to or reset the optlib path list.
-	By default, the optlib path list is empty.
+	See "`Default optlib path list`_" about the default elements for optlib path list.
 
 optlib Options
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -2203,6 +2203,19 @@ Preloading option files
 
 	``*.ctags`` files in a directory are loaded in alphabetical order.
 
+Default optlib path list
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+``$XDG_CONFIG_HOME/ctags``, or ``$HOME/.config/ctags`` if
+``$XDG_CONFIG_HOME`` is not defined
+(on other than MS Windows)
+
+``$HOME/.ctags.d``
+
+``$HOMEDRIVE$HOMEPATH/ctags.d`` (on MS Windows only)
+
+	These directories are parts of the optlib path list by default.
+	See "`Option File Options`_" about the optlib path list.
 
 SEE ALSO
 --------