c2: add list iterating functions

Also renames free_wincondlst to c2_list_free and move it to c2.h.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

src/c2.c

@@ -1675,3 +1675,18 @@ bool c2_match(session_t *ps, const struct managed_win *w, const c2_lptr_t *condl
 
 	return false;
 }
+
+/// Iterate over all conditions in a condition linked list. Call the callback for each of
+/// the conditions. If the callback returns true, the iteration stops early.
+void c2_list_foreach(const c2_lptr_t *condlist, c2_list_foreach_cb_t cb, void *data) {
+	for (auto i = condlist; i; condlist = condlist->next) {
+		if (cb(i, data)) {
+			break;
+		}
+	}
+}
+
+/// Return user data stored in a condition.
+void *c2_list_get_data(const c2_lptr_t *condlist) {
+	return condlist->data;
+}

src/c2.h

@@ -12,6 +12,7 @@
 #pragma once
 
 #include <stdbool.h>
+#include <stddef.h>
 
 typedef struct _c2_lptr c2_lptr_t;
 typedef struct session session_t;
@@ -21,6 +22,20 @@ c2_lptr_t *c2_parse(c2_lptr_t **pcondlst, const char *pattern, void *data);
 
 c2_lptr_t *c2_free_lptr(c2_lptr_t *lp);
 
-bool c2_match(session_t *ps, const struct managed_win *w, const c2_lptr_t *condlst, void **pdata);
+bool c2_match(session_t *ps, const struct managed_win *w, const c2_lptr_t *condlst,
+              void **pdata);
 
 bool c2_list_postprocess(session_t *ps, c2_lptr_t *list);
+typedef bool (*c2_list_foreach_cb_t)(const c2_lptr_t *cond, void *data);
+void c2_list_foreach(const c2_lptr_t *list, c2_list_foreach_cb_t cb, void *data);
+/// Return user data stored in a condition.
+void *c2_list_get_data(const c2_lptr_t *condlist);
+
+/**
+ * Destroy a condition list.
+ */
+static inline void c2_list_free(c2_lptr_t **pcondlst) {
+	while ((*pcondlst = c2_free_lptr(*pcondlst))) {
+	}
+	*pcondlst = NULL;
+}

src/picom.c

@@ -2164,16 +2164,16 @@ static void session_destroy(session_t *ps) {
 	list_init_head(&ps->window_stack);
 
 	// Free blacklists
-	free_wincondlst(&ps->o.shadow_blacklist);
-	free_wincondlst(&ps->o.shadow_clip_list);
-	free_wincondlst(&ps->o.fade_blacklist);
-	free_wincondlst(&ps->o.focus_blacklist);
-	free_wincondlst(&ps->o.invert_color_list);
-	free_wincondlst(&ps->o.blur_background_blacklist);
-	free_wincondlst(&ps->o.opacity_rules);
-	free_wincondlst(&ps->o.paint_blacklist);
-	free_wincondlst(&ps->o.unredir_if_possible_blacklist);
-	free_wincondlst(&ps->o.rounded_corners_blacklist);
+	c2_list_free(&ps->o.shadow_blacklist);
+	c2_list_free(&ps->o.shadow_clip_list);
+	c2_list_free(&ps->o.fade_blacklist);
+	c2_list_free(&ps->o.focus_blacklist);
+	c2_list_free(&ps->o.invert_color_list);
+	c2_list_free(&ps->o.blur_background_blacklist);
+	c2_list_free(&ps->o.opacity_rules);
+	c2_list_free(&ps->o.paint_blacklist);
+	c2_list_free(&ps->o.unredir_if_possible_blacklist);
+	c2_list_free(&ps->o.rounded_corners_blacklist);
 
 	// Free tracked atom list
 	{

src/picom.h

@@ -84,14 +84,6 @@ static inline bool array_wid_exists(const xcb_window_t *arr, int count, xcb_wind
 	return false;
 }
 
-/**
- * Destroy a condition list.
- */
-static inline void free_wincondlst(c2_lptr_t **pcondlst) {
-	while ((*pcondlst = c2_free_lptr(*pcondlst)))
-		continue;
-}
-
 #ifndef CONFIG_OPENGL
 static inline void free_paint_glx(session_t *ps attr_unused, paint_t *p attr_unused) {
 }