diff --git a/src/common.h b/src/common.h
index 6a69e36..fa3bc4b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -393,10 +393,7 @@ typedef struct session {
/// A hash table of all windows.
win *windows;
/// Windows in their stacking order
- win *window_stack;
- /// Pointer to the `next` field of the bottom most window,
- /// or a pointer to `window_stack` when there is no window
- win **window_stack_bottom;
+ struct list_node window_stack;
/// Pointer to win of current active window. Used by
/// EWMH _NET_ACTIVE_WINDOW focus detection. In theory,
/// it's more reliable to store the window ID directly here, just in
diff --git a/src/compton.c b/src/compton.c
index 9fc4a77..5983544 100644
--- a/src/compton.c
+++ b/src/compton.c
@@ -52,6 +52,7 @@
#include "event.h"
#include "options.h"
#include "uthash_extra.h"
+#include "list.h"
/// Get session_t pointer from a pointer to a member of session_t
#define session_ptr(ptr, member) \
@@ -437,7 +438,7 @@ static win *paint_preprocess(session_t *ps, bool *fade_running) {
ps->fade_time += steps * ps->o.fade_delta;
// First, let's process fading
- WIN_STACK_ITER(ps, w) {
+ list_foreach_safe(win, w, &ps->window_stack, stack_neighbour) {
const winmode_t mode_old = w->mode;
const bool was_painted = w->to_paint;
const double opacity_old = w->opacity;
@@ -490,7 +491,7 @@ static win *paint_preprocess(session_t *ps, bool *fade_running) {
// Track whether it's the highest window to paint
bool is_highest = true;
bool reg_ignore_valid = true;
- WIN_STACK_ITER(ps, w) {
+ list_foreach(win, w, &ps->window_stack, stack_neighbour) {
__label__ skip_window;
bool to_paint = true;
// w->to_paint remembers whether this window is painted last time
@@ -650,12 +651,10 @@ static void rebuild_shadow_exclude_reg(session_t *ps) {
static void restack_win(session_t *ps, win *w, xcb_window_t new_above) {
xcb_window_t old_above;
- if (w->next) {
- old_above = w->next->id;
- assert(&w->next != ps->window_stack_bottom);
+ if (!list_node_is_last(&ps->window_stack, &w->stack_neighbour)) {
+ old_above = list_next_entry(w, stack_neighbour)->id;
} else {
old_above = XCB_NONE;
- assert(&w->next == ps->window_stack_bottom);
}
log_debug("Restack %#010x (%s), old_above: %#010x, new_above: %#010x", w->id,
w->name, old_above, new_above);
@@ -663,45 +662,31 @@ static void restack_win(session_t *ps, win *w, xcb_window_t new_above) {
if (old_above != new_above) {
w->reg_ignore_valid = false;
rc_region_unref(&w->reg_ignore);
- if (w->next) {
- w->next->reg_ignore_valid = false;
- rc_region_unref(&w->next->reg_ignore);
- }
-
- win **prev = NULL, *tmp_w;
- HASH_FIND_INT(ps->windows, &new_above, tmp_w);
-
- if (new_above && !tmp_w) {
- log_error("(%#010x, %#010x): Failed to found new above window.",
- w->id, new_above);
- return;
- }
-
- // Unlink from old position
- *w->prev = w->next;
- if (w->next) {
- w->next->prev = w->prev;
- }
- if (ps->window_stack_bottom == &w->next) {
- ps->window_stack_bottom = w->prev;
+ if (!list_node_is_last(&ps->window_stack, &w->stack_neighbour)) {
+ auto next_w = list_next_entry(w, stack_neighbour);
+ next_w->reg_ignore_valid = false;
+ rc_region_unref(&next_w->reg_ignore);
}
+ struct list_node *new_next;
if (!new_above) {
- *ps->window_stack_bottom = w;
- w->prev = ps->window_stack_bottom;
- ps->window_stack_bottom = &w->next;
- w->next = NULL;
+ new_next = &ps->window_stack;
} else {
- prev = tmp_w->prev;
- // Link to new position
- w->next = *prev;
- if (w->next) {
- w->next->prev = &w->next;
+ win *tmp_w = NULL;
+ HASH_FIND_INT(ps->windows, &new_above, tmp_w);
+
+ if (!tmp_w) {
+ log_error("(%#010x, %#010x): Failed to found new above "
+ "window.",
+ w->id, new_above);
+ return;
}
- w->prev = prev;
- *w->prev = w;
+
+ new_next = &tmp_w->stack_neighbour;
}
+ list_move_before(&w->stack_neighbour, new_next);
+
// add damage for this window
add_damage_from_win(ps, w);
@@ -720,7 +705,7 @@ static void restack_win(session_t *ps, win *w, xcb_window_t new_above) {
/// Free up all the images and deinit the backend
static void destroy_backend(session_t *ps) {
- WIN_STACK_ITER(ps, w) {
+ list_foreach_safe(win, w, &ps->window_stack, stack_neighbour) {
// Wrapping up fading in progress
win_skip_fading(ps, &w);
@@ -808,8 +793,11 @@ void configure_root(session_t *ps, int width, int height) {
ps->damage = ps->damage_ring + ps->ndamage - 1;
// Invalidate reg_ignore from the top
- rc_region_unref(&ps->window_stack->reg_ignore);
- ps->window_stack->reg_ignore_valid = false;
+ if (!list_is_empty(&ps->window_stack)) {
+ auto top_w = list_entry(ps->window_stack.next, win, stack_neighbour);
+ rc_region_unref(&top_w->reg_ignore);
+ top_w->reg_ignore_valid = false;
+ }
#ifdef CONFIG_OPENGL
// GLX root change callback
@@ -904,7 +892,7 @@ void circulate_win(session_t *ps, xcb_circulate_notify_event_t *ce) {
return;
if (ce->place == PlaceOnTop) {
- new_above = ps->window_stack->id;
+ new_above = list_entry(ps->window_stack.next, win, stack_neighbour)->id;
} else {
new_above = XCB_NONE;
}
@@ -1752,7 +1740,6 @@ static session_t *session_init(int argc, char **argv, Display *dpy,
#ifdef CONFIG_DBUS
.dbus_data = NULL,
#endif
- .window_stack = NULL,
};
auto stderr_logger = stderr_logger_new();
@@ -1765,7 +1752,7 @@ static session_t *session_init(int argc, char **argv, Display *dpy,
// Allocate a session and copy default values into it
session_t *ps = cmalloc(session_t);
*ps = s_def;
- ps->window_stack_bottom = &ps->window_stack;
+ list_init_head(&ps->window_stack);
ps->loop = EV_DEFAULT;
pixman_region32_init(&ps->screen_reg);
@@ -2144,7 +2131,7 @@ static session_t *session_init(int argc, char **argv, Display *dpy,
free(reply);
log_trace("Initial stack:");
- WIN_STACK_ITER(ps, w) {
+ list_foreach(win, w, &ps->window_stack, stack_neighbour) {
log_trace("%#010x \"%s\"", w->id, w->name);
}
}
@@ -2195,7 +2182,7 @@ static void session_destroy(session_t *ps) {
// Free window linked list
- WIN_STACK_ITER(ps, w) {
+ list_foreach_safe(win, w, &ps->window_stack, stack_neighbour) {
if (w->state != WSTATE_DESTROYING) {
win_ev_stop(ps, w);
HASH_DEL(ps->windows, w);
@@ -2204,8 +2191,7 @@ static void session_destroy(session_t *ps) {
free_win_res(ps, w);
free(w);
}
- ps->window_stack = NULL;
- ps->window_stack_bottom = &ps->window_stack;
+ list_init_head(&ps->window_stack);
// Free blacklists
free_wincondlst(&ps->o.shadow_blacklist);
diff --git a/src/dbus.c b/src/dbus.c
index 18f74cb..b60934f 100644
--- a/src/dbus.c
+++ b/src/dbus.c
@@ -24,9 +24,10 @@
#include "log.h"
#include "string_utils.h"
#include "types.h"
+#include "uthash_extra.h"
#include "utils.h"
#include "win.h"
-#include "uthash_extra.h"
+#include "list.h"
#include "dbus.h"
@@ -760,7 +761,10 @@ static bool cdbus_process_win_get(session_t *ps, DBusMessage *msg) {
// next
if (!strcmp("next", target)) {
- cdbus_reply_wid(ps, msg, (w->next ? w->next->id : 0));
+ cdbus_reply_wid(ps, msg,
+ (list_node_is_last(&ps->window_stack, &w->stack_neighbour)
+ ? 0
+ : list_next_entry(w, stack_neighbour)->id));
return true;
}
diff --git a/src/list.h b/src/list.h
new file mode 100644
index 0000000..69426ac
--- /dev/null
+++ b/src/list.h
@@ -0,0 +1,99 @@
+#pragma once
+#include
+#include
+
+/**
+ * container_of - cast a member of a structure out to the containing structure
+ * @ptr: the pointer to the member.
+ * @type: the type of the container struct this is embedded in.
+ * @member: the name of the member within the struct.
+ *
+ */
+#define container_of(ptr, type, member) \
+ ({ \
+ const __typeof__(((type *)0)->member) *__mptr = (ptr); \
+ (type *)((char *)__mptr - offsetof(type, member)); \
+ })
+
+struct list_node {
+ struct list_node *next, *prev;
+};
+
+#define list_entry(ptr, type, node) container_of(ptr, type, node)
+#define list_next_entry(ptr, node) list_entry((ptr)->node.next, __typeof__(*(ptr)), node)
+#define list_prev_entry(ptr, node) list_entry((ptr)->node.prev, __typeof__(*(ptr)), node)
+
+/// Insert a new node between two adjacent nodes in the list
+static inline void
+__list_insert_between(struct list_node *restrict prev, struct list_node *restrict next,
+ struct list_node *restrict new_) {
+ new_->prev = prev;
+ new_->next = next;
+ next->prev = new_;
+ prev->next = new_;
+}
+
+/// Insert a new node after `curr`
+static inline void
+list_insert_after(struct list_node *restrict curr, struct list_node *restrict new_) {
+ __list_insert_between(curr, curr->next, new_);
+}
+
+/// Insert a new node before `curr`
+static inline void
+list_insert_before(struct list_node *restrict curr, struct list_node *restrict new_) {
+ __list_insert_between(curr->prev, curr, new_);
+}
+
+/// Link two nodes in the list, so `next` becomes the successor node of `prev`
+static inline void __list_link(struct list_node *prev, struct list_node *next) {
+ next->prev = prev;
+ prev->next = next;
+}
+
+/// Remove a node from the list
+static inline void list_remove(struct list_node *to_remove) {
+ __list_link(to_remove->prev, to_remove->next);
+ to_remove->prev = (void *)-1;
+ to_remove->next = (void *)-2;
+}
+
+/// Move `to_move` so that it's before `new_next`
+static inline void
+list_move_before(struct list_node *restrict to_move, struct list_node *restrict new_next) {
+ list_remove(to_move);
+ list_insert_before(new_next, to_move);
+}
+
+/// Initialize a list node that's intended to be the head node
+static inline void list_init_head(struct list_node *head) {
+ head->next = head->prev = head;
+}
+
+/// Return true if head is the only node in the list. Under usual circumstances this means
+/// the list is empty
+static inline bool list_is_empty(const struct list_node *head) {
+ return head->prev == head;
+}
+
+/// Return true if `to_check` is the first node in list headed by `head`
+static inline bool
+list_node_is_first(const struct list_node *head, const struct list_node *to_check) {
+ return head->next == to_check;
+}
+
+/// Return true if `to_check` is the last node in list headed by `head`
+static inline bool
+list_node_is_last(const struct list_node *head, const struct list_node *to_check) {
+ return head->prev == to_check;
+}
+
+#define list_foreach(type, i, head, member) \
+ for (type *i = list_entry((head)->next, type, member); &i->member != (head); \
+ i = list_next_entry(i, member))
+
+/// Like list_for_each, but it's safe to remove the current list node from the list
+#define list_foreach_safe(type, i, head, member) \
+ for (type *i = list_entry((head)->next, type, member), \
+ *__tmp = list_next_entry(i, member); \
+ &i->member != (head); i = __tmp, __tmp = list_next_entry(i, member))
diff --git a/src/opengl.c b/src/opengl.c
index 08563a3..8683827 100644
--- a/src/opengl.c
+++ b/src/opengl.c
@@ -221,7 +221,7 @@ void glx_destroy(session_t *ps) {
return;
// Free all GLX resources of windows
- WIN_STACK_ITER(ps, w) {
+ list_foreach(win, w, &ps->window_stack, stack_neighbour) {
free_win_res_glx(ps, w);
}
diff --git a/src/win.c b/src/win.c
index 0536d75..2de78c8 100644
--- a/src/win.c
+++ b/src/win.c
@@ -28,6 +28,7 @@
#include "uthash_extra.h"
#include "utils.h"
#include "x.h"
+#include "list.h"
#ifdef CONFIG_DBUS
#include "dbus.h"
@@ -57,7 +58,7 @@
* Clear leader cache of all windows.
*/
static inline void clear_cache_win_leaders(session_t *ps) {
- WIN_STACK_ITER(ps, w) {
+ list_foreach(win, w, &ps->window_stack, stack_neighbour) {
w->cache_leader = XCB_NONE;
}
}
@@ -918,7 +919,6 @@ void add_win(session_t *ps, xcb_window_t id, xcb_window_t prev) {
.invert_color_force = UNSET,
// Initialized in this function
- .next = NULL,
.id = XCB_NONE,
.a = {0},
.pictfmt = NULL,
@@ -1025,24 +1025,16 @@ void add_win(session_t *ps, xcb_window_t id, xcb_window_t prev) {
}
// Find window insertion point
- win **p = NULL;
+ struct list_node *p = NULL;
if (prev) {
win *w = NULL;
HASH_FIND_INT(ps->windows, &prev, w);
assert(w);
- p = w->prev;
+ p = w->stack_neighbour.prev;
} else {
p = &ps->window_stack;
}
- new->next = *p;
- if (new->next) {
- new->next->prev = &new->next;
- }
- new->prev = p;
- *p = new;
- if (p == ps->window_stack_bottom) {
- ps->window_stack_bottom = &new->next;
- }
+ list_insert_after(p, &new->stack_neighbour);
HASH_ADD_INT(ps->windows, id, new);
#ifdef CONFIG_DBUS
@@ -1427,7 +1419,7 @@ void win_update_frame_extents(session_t *ps, win *w, xcb_window_t client) {
}
bool win_is_region_ignore_valid(session_t *ps, const win *w) {
- WIN_STACK_ITER(ps, i) {
+ list_foreach(win, i, &ps->window_stack, stack_neighbour) {
if (i == w)
break;
if (!i->reg_ignore_valid)
@@ -1487,19 +1479,14 @@ static void finish_destroy_win(session_t *ps, win **_w) {
// paint happened at least once, w->reg_ignore_valid would
// be true, and there is no need to invalid w->next->reg_ignore
// when w is destroyed.
- if (w->next) {
- rc_region_unref(&w->next->reg_ignore);
- w->next->reg_ignore_valid = false;
+ if (!list_node_is_last(&ps->window_stack, &w->stack_neighbour)) {
+ auto next_w = list_next_entry(w, stack_neighbour);
+ rc_region_unref(&next_w->reg_ignore);
+ next_w->reg_ignore_valid = false;
}
log_trace("Trying to destroy (%#010x)", w->id);
- *w->prev = w->next;
- if (w->next) {
- w->next->prev = w->prev;
- }
- if (&w->next == ps->window_stack_bottom) {
- ps->window_stack_bottom = w->prev;
- }
+ list_remove(&w->stack_neighbour);
if (w == ps->active_win) {
ps->active_win = NULL;
@@ -1510,7 +1497,7 @@ static void finish_destroy_win(session_t *ps, win **_w) {
// Drop w from all prev_trans to avoid accessing freed memory in
// repair_win()
// TODO there can only be one prev_trans pointing to w
- WIN_STACK_ITER(ps, w2) {
+ list_foreach(win, w2, &ps->window_stack, stack_neighbour) {
if (w == w2->prev_trans) {
w2->prev_trans = NULL;
}
diff --git a/src/win.h b/src/win.h
index 3f74f07..8494c3a 100644
--- a/src/win.h
+++ b/src/win.h
@@ -22,9 +22,7 @@
#include "types.h"
#include "utils.h"
#include "x.h"
-
-#define WIN_STACK_ITER(ps, w) \
- for (win *w = ps->window_stack, *next; w ? (next = w->next, true) : false; w = next)
+#include "list.h"
typedef struct session session_t;
typedef struct _glx_texture glx_texture_t;
@@ -131,14 +129,11 @@ typedef enum win_flags {
/// Structure representing a top-level window compton manages.
typedef struct win win;
struct win {
+ struct list_node stack_neighbour;
/// backend data attached to this window. Only available when
/// `state` is not UNMAPPED
void *win_image;
void *shadow_image;
- /// Pointer to the next lower window in window stack.
- win *next;
- /// Pointer to a linked-list pointer that points to this window.
- win **prev;
/// Pointer to the next higher window to paint.
win *prev_trans;
// TODO rethink reg_ignore