improve performance by a large margin by using a hash table for dispatch targets

src/background-node.c

@@ -1,4 +1,5 @@
 #include "background-node.h"
+#include "node.h"
 #include "window.h"
 
 #ifndef M_PI
@@ -17,6 +18,10 @@ int background_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
     UIBackgroundNode *n = (UIBackgroundNode*)node;
 
     switch (ev) {
+        case UI_EVENT_ATTACHED: {
+            node_notify_subscribe(node->parent, node, (enum UIEvent[]){ UI_EVENT_REPAINT, UI_EVENT_HOVERED, UI_EVENT_UNHOVERED, UI_EVENT_PRESSED, UI_EVENT_UNPRESSED, 0 });
+            break;
+        }
         case UI_EVENT_REPAINT: {
             UIRGBA *color = &n->normal;
             if (n->update_on_status) {

src/box-layout-node.c

@@ -29,6 +29,11 @@ int box_layout_handle(UINode *component, enum UIEvent ev, size_t d, void *p)
     int growing_widgets = 0;
     int current_index = 0;
 
+    if (ev == UI_EVENT_ATTACHED) {
+        node_notify_subscribe(component->parent, component, (enum UIEvent[]){ UI_EVENT_RELAYOUT, UI_EVENT_GET_EXTENTS, 0 });
+        return 0;
+    }
+
     if (ev == UI_EVENT_RELAYOUT || ev == UI_EVENT_GET_EXTENTS) {
         for (int i = 0; i < node->nodes_count; i++) {
             UINode *current = node->nodes[i];

src/defs.h

@@ -5,4 +5,22 @@
 #define _UI_DEBUG
 #endif
 
+#define UI_ENABLE_BRANCH_HINTS
+
+#ifdef UI_ENABLE_BRANCH_HINTS
+#  ifdef __has_builtin
+#    if __has_builtin(__builtin_expect)
+#      define __UI_UTIL_CAN_USE_BRANCH_HINTS
+#    endif
+#  endif
+#endif
+
+#ifdef __UI_UTIL_CAN_USE_BRANCH_HINTS
+#  define unlikely(M_expr) __builtin_expect(!!(M_expr), 0)
+#  define likely(M_expr) __builtin_expect(!!(M_expr), 1)
+#else
+#  define unlikely(M_expr) (M_expr)
+#  define likely(M_expr) (M_expr)
+#endif
+
 #endif // _UI__DEFS_H

src/dispatcher-node.c

@@ -1,5 +1,6 @@
 #include <stdlib.h>
 #include "dispatcher-node.h"
+#include "node.h"
 
 int dispatcher_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
 {
@@ -9,6 +10,10 @@ int dispatcher_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
 
     UIDispatcherNode *n = (UIDispatcherNode*)node;
 
+    if (ev == UI_EVENT_ATTACHED) {
+        node_notify_subscribe(node->parent, node, (enum UIEvent[]){ n->node_event_type, 0 });
+    }
+
     if (ev == n->node_event_type) {
         (n->handle)(node->parent, n->data, n->event_type, d, p);
     }

src/main.c

@@ -130,7 +130,7 @@ int app_handle(struct UINode *node, void *data, int event_type, size_t d, void *
 
                 box_layout_new(buttons, UI_DIRECTION_VERTICAL);
 
-                for (int i = 0; i < 3; i++) {
+                for (int i = 0; i < 10000; i++) {
                     UINode *button = node_new(buttons, "button");
                     state_background_node_new(button, UIPurple600, UIPurple700, UIPurple800, 6.0);
                     text_node_new(button, state->font, UINeutral50, "button");

src/node.c

@@ -1,11 +1,28 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include "defs.h"
 #include "node.h"
 #include "rect.h"
 
 typedef struct UIWindow UIWindow;
 int window_invalidate_node(UIWindow *window, UINode *node);
 
+static inline uint32_t hash_ui_event(enum UIEvent ev, int count)
+{
+    if (ev < UI_EVENT__LAST) {
+        return UI_EVENT_BUCKET_INDEX[ev];
+    }
+
+    // FNV-1a
+    uint32_t hash = 0x811c9dc5;
+    for (size_t i = 0; i < sizeof(enum UIEvent); i++) {
+        hash ^= ((char*)&ev)[i];
+        hash *= 0x01000193;
+    }
+
+    return hash % count;
+}
+
 UIRect node_get_computed_rect(UINode *node) {
     UIRect rect = node->rect;
     UIRect extents = node->rect;
@@ -26,7 +43,7 @@ UIRect node_get_computed_rect(UINode *node) {
 
 int node_send(UINode *node, enum UIEvent ev, size_t d, void *p)
 {
-    if (node->flags & UI_NODE_DISABLED) {
+    if (unlikely(node->flags & UI_NODE_DISABLED)) {
         return 0;
     }
 
@@ -42,34 +59,36 @@ int node_send(UINode *node, enum UIEvent ev, size_t d, void *p)
 
 int node_dispatch(UINode *node, enum UIEvent ev, size_t d, void *p)
 {
-    if (node->flags & UI_NODE_DISABLED) {
+    if (unlikely(!node || node->flags & UI_NODE_DISABLED)) {
         return 0;
     }
 
     int result = 0;
-    int component_index = UI_NODE_LAST_COMPONENT_INDEX_NONE;
-    for (int i = 0; i < node->nodes_count; i++) {
-        if (node->last_component_index == UI_NODE_LAST_COMPONENT_INDEX_NONE || (node->last_component_index >= 0 && i > node->last_component_index)) {
-            break;
-        }
-        if (node->nodes[i]->flags & UI_NODE_COMPONENT) {
-            component_index = i;
-            result = node_send(node->nodes[i], ev, d, p);
-            if (result) break;
-        }
-    }
-    if (node->last_component_index < 0) {
-        node->last_component_index = component_index;
-    }
-    if (result) return result;
 
     if (node->handle) {
         result = (node->handle)(node, ev, d, p);
         if (result) return result;
     }
     if (node->handle_proto) {
-        return (node->handle_proto)(node, ev, d, p);
+        result = (node->handle_proto)(node, ev, d, p);
+        if (result) return result;
     }
+
+    uint32_t hash = hash_ui_event(ev, UI_NODE_DISPATCH_BUCKETS);
+    UINodeDispatchBucket *bucket = &node->dispatch_buckets[hash];
+    for (int i = 0; i < bucket->count; i++) {
+        UINode *n = bucket->elements[i];
+        // We prioritize handle_proto for components
+        if (n->handle_proto) {
+            result = (n->handle_proto)(n, ev, d, p);
+            if (result) return result;
+        }
+        if (n->handle) {
+            result = (n->handle)(n, ev, d, p);
+            if (result) return result;
+        }
+    }
+
     return 0;
 }
 
@@ -100,8 +119,36 @@ void node_init(UINode *node)
     node->height_policy = UI_SIZE_POLICY_COMPUTED;
     node->handle = NULL;
     node->handle_proto = NULL;
-    node->last_component_index = UI_NODE_LAST_COMPONENT_INDEX_NONE;
     node->cached_computed_extents = false;
+    for (int i = 0; i < UI_NODE_DISPATCH_BUCKETS; i++) {
+        node->dispatch_buckets[i].capacity = 0;
+        node->dispatch_buckets[i].count = 0;
+        node->dispatch_buckets[i].elements = NULL;
+    }
+}
+
+static inline void node_add_dispatch_target(UINode *node, enum UIEvent ev, UINode *target)
+{
+    uint32_t index = hash_ui_event(ev, UI_NODE_DISPATCH_BUCKETS);
+
+    UINodeDispatchBucket *bucket = &node->dispatch_buckets[index];
+    if (bucket->count >= bucket->capacity) {
+        bucket->capacity += 2;
+        bucket->elements = realloc(bucket->elements, bucket->capacity * sizeof(bucket->elements));
+        if (!bucket->elements) {
+            return;
+        }
+    }
+
+    int node_index = bucket->count++;
+    bucket->elements[node_index] = target;
+}
+
+void node_notify_subscribe(UINode *node, UINode *target, enum UIEvent *event)
+{
+    for (; *event; event++) {
+        node_add_dispatch_target(node, *event, target);
+    }
 }
 
 void node_free(UINode *node)
@@ -110,11 +157,6 @@ void node_free(UINode *node)
 
     // TODO: properly handle removing this node from its parent
 
-    // Invalidate component index cache
-    if ((node->flags & UI_NODE_COMPONENT) && node->parent) {
-        node->parent->last_component_index = UI_NODE_LAST_COMPONENT_INDEX_INVALIDATED;
-    }
-
     node_dispatch(node, UI_EVENT_DESTROY, 0, NULL);
 
     for (int i = 0; i < node->nodes_count; i++) {
@@ -176,11 +218,7 @@ UINode *node_attach(UINode *parent, UINode *node)
         int index = parent->nodes_count++;
         parent->nodes[index] = node;
 
-        // Let's save the index of the last component so that we can exit the loop early
-        // if there's no components left when we're in node_dispatch()
-        if ((node->flags & UI_NODE_COMPONENT) && index > parent->last_component_index) {
-            parent->last_component_index = index;
-        }
+        node_send(node, UI_EVENT_ATTACHED, 0, 0);
     }
 
     return node;

src/node.h

@@ -9,6 +9,11 @@
 #define UI_NODE_COMPUTED_EXTENTS_OK (1)
 #define UI_NODE_COMPUTED_EXTENTS_CACHED (2)
 enum UIEvent {
+    UI_EVENT_NONE = 0,
+
+    UI_EVENT_ATTACHED,
+    UI_EVENT_DESTROY,
+
     UI_EVENT_REPAINT,
     UI_EVENT_RELAYOUT,
     UI_EVENT_GET_EXTENTS,
@@ -16,7 +21,6 @@ enum UIEvent {
     UI_EVENT_UNHOVERED,
     UI_EVENT_PRESSED,
     UI_EVENT_UNPRESSED,
-    UI_EVENT_DESTROY,
 
     UI_EVENT_TIMER_END,
 
@@ -24,6 +28,26 @@ enum UIEvent {
     UI_EVENT_BUTTON_RIGHT_UPDATE, // d == 1 if pressed, d == 0 if released
     UI_EVENT_SCROLL, // p (double*) = delta
     UI_EVENT_KEY_DOWN, // d (unsigned int) = keycode, p (struct xkb_state*) = xkb state
+
+    UI_EVENT__LAST,
+};
+
+static const int UI_EVENT_BUCKET_INDEX[] = {
+    [UI_EVENT_NONE] = 0,
+    [UI_EVENT_ATTACHED] = 0,
+    [UI_EVENT_DESTROY] = 0,
+    [UI_EVENT_TIMER_END] = 0,
+    [UI_EVENT_RELAYOUT] = 1,
+    [UI_EVENT_GET_EXTENTS] = 2,
+    [UI_EVENT_REPAINT] = 3,
+    [UI_EVENT_HOVERED] = 4,
+    [UI_EVENT_UNHOVERED] = 4,
+    [UI_EVENT_PRESSED] = 5,
+    [UI_EVENT_UNPRESSED] = 5,
+    [UI_EVENT_SCROLL] = 5,
+    [UI_EVENT_BUTTON_LEFT_UPDATE] = 6,
+    [UI_EVENT_BUTTON_RIGHT_UPDATE] = 6,
+    [UI_EVENT_KEY_DOWN] = 6,
 };
 
 enum UISizePolicy {
@@ -38,12 +62,16 @@ enum UIDirection {
     UI_DIRECTION_VERTICAL
 };
 
+typedef struct UINodeDispatchBucket {
+    int capacity, count;
+    struct UINode **elements;
+} UINodeDispatchBucket;
+
 #define UI_NODE_COMPONENT (1 << 0)
 #define UI_NODE_RETAINS_PRESS (1 << 1)
 #define UI_NODE_DISABLED (1 << 2)
 
-#define UI_NODE_LAST_COMPONENT_INDEX_INVALIDATED (-1)
-#define UI_NODE_LAST_COMPONENT_INDEX_NONE (-2)
+#define UI_NODE_DISPATCH_BUCKETS (7)
 typedef struct UINode {
     const char *text;
     UIRect rect;
@@ -56,8 +84,9 @@ typedef struct UINode {
     uint32_t flags;
     enum UISizePolicy width_policy;
     enum UISizePolicy height_policy;
-    int last_component_index;
     bool cached_computed_extents;
+    
+    UINodeDispatchBucket dispatch_buckets[UI_NODE_DISPATCH_BUCKETS];
 
     int (*handle)(struct UINode *node, enum UIEvent ev, size_t d, void *p);
     int (*handle_proto)(struct UINode *node, enum UIEvent ev, size_t d, void *p);
@@ -74,5 +103,6 @@ UINode *node_attach(UINode *parent, UINode *node);
 UINode *node_new(UINode *parent, const char *text);
 void node_dump(UINode *node, int depth);
 void node_request_relayout(UINode *node);
+void node_notify_subscribe(UINode *node, UINode *target, enum UIEvent *events);
 
 #endif // _UI__NODE_H

src/scrollable-node.c

@@ -27,13 +27,19 @@ int scrollable_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
     UIScrollableNode *n = (UIScrollableNode *)node;
     UINode *target = n->target;
 
-    if (!n->node.parent || !target) {
+    if (!node->parent) {
         return 0;
     }
 
     // TODO: horizontal scroll
     switch (ev) {
+        case UI_EVENT_ATTACHED: {
+            node_notify_subscribe(node->parent, node, (enum UIEvent[]){ UI_EVENT_SCROLL, UI_EVENT_RELAYOUT, 0 });
+            break;
+        }
         case UI_EVENT_SCROLL: {
+            if (!target) return 0;
+
             double scroll_end = target->rect.h - node->parent->rect.h;
             if (scroll_end < 0) scroll_end = 0;
 
@@ -50,6 +56,8 @@ int scrollable_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
             break;
         }
         case UI_EVENT_RELAYOUT: {
+            if (!target) return 0;
+
             UIRect rect = {0};
             node_dispatch(target, UI_EVENT_GET_EXTENTS, 0, &rect);
             target->rect.w = target->width_policy == UI_SIZE_POLICY_GROW ? node->parent->rect.w : rect.w;

src/text-input-node.c

@@ -25,6 +25,10 @@ int text_input_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
     UITextInputNode *n = (UITextInputNode *)node;
 
     switch (ev) {
+        case UI_EVENT_ATTACHED: {
+            node_notify_subscribe(node->parent, node, (enum UIEvent[]){ UI_EVENT_KEY_DOWN, UI_EVENT_PRESSED, UI_EVENT_UNPRESSED, 0 });
+            break;
+        }
         case UI_EVENT_KEY_DOWN: {
             xkb_keycode_t keycode = d;
             struct xkb_state *xkb_state = (struct xkb_state*)p;

src/text-node.c

@@ -52,6 +52,10 @@ int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
     }
 
     switch (ev) {
+        case UI_EVENT_ATTACHED: {
+            node_notify_subscribe(node->parent, node, (enum UIEvent[]){ UI_EVENT_REPAINT, UI_EVENT_GET_EXTENTS, UI_EVENT_RELAYOUT, UI_EVENT_DESTROY, 0 });
+            break;
+        }
         case UI_EVENT_REPAINT: {
             if (!n->layout) {
                 break;