Use list_find in more places and refactor/fix workspace prev_next functions

The original purpose of this commit is to replace some for loops with
list_find. But while doing this I found the workspace_prev_next_impl
functions to be difficult to read and also contained a bug, so I
refactored them and fixed the bug.

To reproduce the bug:

* Have two outputs, where the left output has workspaces 1, 2, 3 and the
right output has workspaces 4, 5, 6. Make workspace 2 focused_inactive
and workspace 4 focused.
* Run `workspace prev`.
* Previously it would visit the left output, then apply `workspace prev`
to workspace 2, which focuses workspace 1.
* Now it will focus the rightmost workspace on the left output
(workspace 3).

The refactoring I made to the workspace functions are:

* Added the static keyword.
* They now accept an int dir rather than bool, to avoid an unnecessary
conversion.
* Rather than preparing start and end variables for the purpose of
iterating, just iterate everything.
* Replace for loops with list_find.
* Don't call workspace_output_prev_next_impl (this fixes the bug).

1 files changed, 4 insertions, 13 deletions

diff --git a/sway/tree/layout.c b/sway/tree/layout.c
index 38e14d00..2b710403 100644
--- a/sway/tree/layout.c
+++ b/sway/tree/layout.c
@@ -20,14 +20,7 @@
 #include "log.h"
 
 static int index_child(const struct sway_container *child) {
-        struct sway_container *parent = child->parent;
-        for (int i = 0; i < parent->children->length; ++i) {
-                if (parent->children->items[i] == child) {
-                        return i;
-                }
-        }
-        // This happens if the child is a floating container
-        return -1;
+        return list_find(child->parent->children, child);
 }
 
 static void container_handle_fullscreen_reparent(struct sway_container *con,
@@ -125,11 +118,9 @@ struct sway_container *container_remove_child(struct sway_container *child) {
         }
 
         struct sway_container *parent = child->parent;
-        for (int i = 0; i < parent->children->length; ++i) {
-                if (parent->children->items[i] == child) {
-                        list_del(parent->children, i);
-                        break;
-                }
+        int index = index_child(child);
+        if (index != -1) {
+                list_del(parent->children, index);
         }
         child->parent = NULL;
         container_notify_subtree_changed(parent);