improve performance by caching the index of the last component node

Makefile

@@ -13,7 +13,7 @@ OBJS=$(patsubst $(SRC)/%.c, $(OBJ)/%.o, $(SRCS))
 DEPS=$(OBJS:%.o=%.d)
 
 
-all: CFLAGS+=-fsanitize=address -Og -ggdb
+all: CFLAGS+=-Og -ggdb -DNDEBUG
 all: $(BUILD) $(BIN)
 
 release: CFLAGS+=-O2 -flto=auto -DNDEBUG

src/main.c

@@ -130,13 +130,15 @@ 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 < 100; 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");
                     dispatcher_new(button, UI_EVENT_UNPRESSED, INCREMENT_COUNT, state, app_handle);
                     button->width_policy = UI_SIZE_POLICY_GROW;
                 }
+
+                printf("%d\n", buttons->last_component_index);
             }
 
             break;

src/node.c

@@ -28,14 +28,25 @@ int node_dispatch(UINode *node, enum UIEvent ev, size_t d, void *p)
         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) {
-            int result = node_dispatch(node->nodes[i], ev, d, p);
+            component_index = i;
+            result = node_dispatch(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) {
-        int result = (node->handle)(node, ev, d, p);
+        result = (node->handle)(node, ev, d, p);
         if (result) return result;
     }
     if (node->handle_proto) {
@@ -71,12 +82,20 @@ void node_init(UINode *node)
     node->height_policy = UI_SIZE_POLICY_DYNAMIC;
     node->handle = NULL;
     node->handle_proto = NULL;
+    node->last_component_index = UI_NODE_LAST_COMPONENT_INDEX_NONE;
 }
 
 void node_free(UINode *node)
 {
     if (!node) return;
 
+    // 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++) {
@@ -135,7 +154,14 @@ UINode *node_attach(UINode *parent, UINode *node)
                 return NULL;
             }
         }
-        parent->nodes[parent->nodes_count++] = 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;
+        }
     }
 
     return node;

src/node.h

@@ -41,6 +41,8 @@ enum UIDirection {
 #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)
 typedef struct UINode {
     const char *text;
     UIRect rect;
@@ -53,6 +55,7 @@ typedef struct UINode {
     uint32_t flags;
     enum UISizePolicy width_policy;
     enum UISizePolicy height_policy;
+    int last_component_index;
 
     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);

src/text-node.c

@@ -17,6 +17,9 @@ UITextNode *text_node_new(UINode *parent, PangoFontDescription *desc, UIRGBA col
     n->color = color;
     n->caret_index = -1;
     n->caret_node = NULL;
+    n->computed_dimensions_invalid = true;
+    n->computed_text_width = 0;
+    n->computed_text_height = 0;
     n->node.text = "text";
     n->node.handle_proto = text_node_handle;
     node_attach(parent, (UINode*)n);
@@ -47,6 +50,7 @@ int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
             n->layout = layout;
             n->pending_text = NULL;
         }
+        n->computed_dimensions_invalid = true;
     }
 
     switch (ev) {
@@ -59,23 +63,22 @@ int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p)
             cairo_fill(n->node.drw);
             break;
         }
-        case UI_EVENT_GET_WIDTH: {
-            if (!n->layout) {
-                break;
-            }
-            int w;
-            pango_layout_get_size(n->layout, &w, NULL);
-            *(double*)p = pango_units_to_double(w);
-            return 1;
-        }
+        case UI_EVENT_GET_WIDTH: /* through */
         case UI_EVENT_GET_HEIGHT: {
-            if (!n->layout) {
-                break;
+            if (n->computed_dimensions_invalid) {
+                int w, h = 0;
+                pango_layout_get_size(n->layout, &w, &h);
+                n->computed_text_width = pango_units_to_double(w);
+                n->computed_text_height = pango_units_to_double(h);
+                n->computed_dimensions_invalid = false;
             }
-            int h;
-            pango_layout_get_size(n->layout, NULL, &h);
-            *(double*)p = pango_units_to_double(h);
-            return 1;
+            if (ev == UI_EVENT_GET_WIDTH) {
+                *(double*)p = n->computed_text_width;
+            }
+            if (ev == UI_EVENT_GET_HEIGHT) {
+                *(double*)p = n->computed_text_height;
+            }
+            break;
         }
         case UI_EVENT_RELAYOUT: {
             if (!n->layout) {

src/text-node.h

@@ -15,6 +15,9 @@ typedef struct UITextNode {
     UIRGBA color;
     ssize_t caret_index;
     UINode *caret_node;
+    double computed_text_width;
+    double computed_text_height;
+    bool computed_dimensions_invalid;
 } UITextNode;
 
 int text_node_handle(UINode *node, enum UIEvent ev, size_t d, void *p);