#141 fix space padding and gap underflow when modified with a relativ…

…e value

CHANGELOG.md

@@ -10,6 +10,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Work around macOS craziness so that we can properly tile a window after it leaves native fullscreen mode [#36](https://github.com/koekeishiya/yabai/issues/36)
 - Return an error for queries with invalid, named selectors [#158](https://github.com/koekeishiya/yabai/issues/158)
 - Resolve a potential multi-threaded issue due to "undefined behaviour" regarding x86 instruction ordering [#153](https://github.com/koekeishiya/yabai/issues/153)
+- Fix space padding and gap underflow when modified with a relative value [#141](https://github.com/koekeishiya/yabai/issues/141)
 
 ## [1.1.2] - 2019-07-15
 ### Changed

src/misc/macros.h

@@ -4,6 +4,7 @@
 #define array_count(a) (sizeof((a)) / sizeof(*(a)))
 #define min(a, b) ((a) < (b) ? (a) : (b))
 #define max(a, b) ((a) > (b) ? (a) : (b))
+#define add_and_clamp_to_zero(a, b) (((a) + (b) <= 0) ? 0 : (a) + (b))
 
 #define MAXLEN 512
 

src/space_manager.c

@@ -178,7 +178,7 @@ void space_manager_set_gap_for_space(struct space_manager *sm, uint64_t sid, int
     if (type == TYPE_ABS) {
         view->window_gap = gap;
     } else if (type == TYPE_REL) {
-        view->window_gap += gap;
+        view->window_gap = add_and_clamp_to_zero(view->window_gap, gap);
     }
 
     view_update(view);
@@ -272,10 +272,10 @@ void space_manager_set_padding_for_space(struct space_manager *sm, uint64_t sid,
         view->left_padding   = left;
         view->right_padding  = right;
     } else if (type == TYPE_REL) {
-        view->top_padding    += top;
-        view->bottom_padding += bottom;
-        view->left_padding   += left;
-        view->right_padding  += right;
+        view->top_padding    = add_and_clamp_to_zero(view->top_padding, top);
+        view->bottom_padding = add_and_clamp_to_zero(view->bottom_padding, bottom);
+        view->left_padding   = add_and_clamp_to_zero(view->left_padding, left);
+        view->right_padding  = add_and_clamp_to_zero(view->right_padding, right);
     }
 
     view_update(view);

src/view.h

@@ -79,11 +79,11 @@ struct view
     struct window_node *root;
     enum view_type layout;
     uint32_t insertion_point;
-    uint32_t top_padding;
-    uint32_t bottom_padding;
-    uint32_t left_padding;
-    uint32_t right_padding;
-    uint32_t window_gap;
+    int top_padding;
+    int bottom_padding;
+    int left_padding;
+    int right_padding;
+    int window_gap;
     bool custom_layout;
     bool custom_top_padding;
     bool custom_bottom_padding;