From 1c77126fe61d3ba7ff3a0abcef10836ab65a0f61 Mon Sep 17 00:00:00 2001
From: Andrey Antukh <niwi@niwi.nz>
Date: Wed, 9 Apr 2025 15:57:07 +0200
Subject: [PATCH] :zap: Implement get-handlers in term of internal reduce

That has an average performance improvement of 64% over
original impl and reduction of generation of object garbage
---
 common/src/app/common/types/path/segment.cljc | 34 +++++++++----------
 .../common_tests/types/path_data_test.cljc    | 28 +++++++++++++++
 .../app/main/data/workspace/path/drawing.cljs |  2 +-
 .../main/ui/workspace/shapes/path/editor.cljs |  5 +--
 4 files changed, 49 insertions(+), 20 deletions(-)

diff --git a/common/src/app/common/types/path/segment.cljc b/common/src/app/common/types/path/segment.cljc
index f5e082459..2bf9f471d 100644
--- a/common/src/app/common/types/path/segment.cljc
+++ b/common/src/app/common/types/path/segment.cljc
@@ -34,24 +34,24 @@
       (gpt/point (get params cx)
                  (get params cy)))))
 
-;; FIXME: rename segments->handlers
-(defn content->handlers
+(defn get-handlers
   "Retrieve a map where for every point will retrieve a list of
   the handlers that are associated with that point.
   point -> [[index, prefix]]"
   [content]
-  (->> (d/with-prev content)
-       (d/enumerate)
-       (mapcat (fn [[index [cur-segment pre-segment]]]
-                 (if (and pre-segment (= :curve-to (:command cur-segment)))
-                   (let [cur-pos (helpers/segment->point cur-segment)
-                         pre-pos (helpers/segment->point pre-segment)]
-                     (-> [[pre-pos [index :c1]]
-                          [cur-pos [index :c2]]]))
-                   [])))
-
-       (group-by first)
-       (d/mapm #(mapv second %2))))
+  (let [prev-point* (volatile! nil)
+        vec-conj    (fnil conj [])]
+    (impl/-reduce content
+                  (fn [result index type _ _ _ _ x y]
+                    (let [curr-point (gpt/point x y)
+                          prev-point (deref prev-point*)]
+                      (vreset! prev-point* curr-point)
+                      (if (and prev-point (= :curve-to type))
+                        (-> result
+                            (update prev-point vec-conj [index :c1])
+                            (update curr-point vec-conj [index :c2]))
+                        result)))
+                  {})))
 
 (defn point-indices
   [content point]
@@ -81,7 +81,7 @@
                 (helpers/segment->point (nth content index))
                 (helpers/segment->point (nth content (dec index))))
 
-        point->handlers (content->handlers content)
+        point->handlers (get-handlers content)
 
         handlers (->> point
                       (point->handlers)
@@ -350,7 +350,7 @@
 (defn make-corner-point
   "Changes the content to make a point a 'corner'"
   [content point]
-  (let [handlers (-> (content->handlers content)
+  (let [handlers (-> (get-handlers content)
                      (get point))
         change-content
         (fn [content [index prefix]]
@@ -395,7 +395,7 @@
 ;; FIXME: optimize
 (defn is-curve?
   [content point]
-  (let [handlers (-> (content->handlers content)
+  (let [handlers (-> (get-handlers content)
                      (get point))
         handler-points (map #(get-handler-point content (first %) (second %)) handlers)]
     (some #(not= point %) handler-points)))
diff --git a/common/test/common_tests/types/path_data_test.cljc b/common/test/common_tests/types/path_data_test.cljc
index 4e6c21da8..6aab6c335 100644
--- a/common/test/common_tests/types/path_data_test.cljc
+++ b/common/test/common_tests/types/path_data_test.cljc
@@ -340,3 +340,31 @@
     (t/is (= result4 expect1))
     (t/is (= result5 expect2))
     (t/is (= result6 expect3))))
+
+
+(defn get-handlers
+  "Retrieve a map where for every point will retrieve a list of
+  the handlers that are associated with that point.
+  point -> [[index, prefix]].
+
+  Legacy impl"
+  [content]
+  (->> (d/with-prev content)
+       (d/enumerate)
+       (mapcat (fn [[index [cur-segment pre-segment]]]
+                 (if (and pre-segment (= :curve-to (:command cur-segment)))
+                   (let [cur-pos (path.helpers/segment->point cur-segment)
+                         pre-pos (path.helpers/segment->point pre-segment)]
+                     (-> [[pre-pos [index :c1]]
+                          [cur-pos [index :c2]]]))
+                   [])))
+
+       (group-by first)
+       (d/mapm #(mapv second %2))))
+
+(t/deftest content-to-handlers
+  (let [content (path/content sample-content-large)
+        result1 (get-handlers content)
+        result2 (path.segment/get-handlers content)]
+
+    (t/is (= result1 result2))))
diff --git a/frontend/src/app/main/data/workspace/path/drawing.cljs b/frontend/src/app/main/data/workspace/path/drawing.cljs
index 191e097b5..7d9eb3cdb 100644
--- a/frontend/src/app/main/data/workspace/path/drawing.cljs
+++ b/frontend/src/app/main/data/workspace/path/drawing.cljs
@@ -129,7 +129,7 @@
     ptk/WatchEvent
     (watch [_ state stream]
       (let [content  (st/get-path state :content)
-            handlers (-> (path.segment/content->handlers content)
+            handlers (-> (path.segment/get-handlers content)
                          (get position))
 
             [idx prefix] (when (= (count handlers) 1)
diff --git a/frontend/src/app/main/ui/workspace/shapes/path/editor.cljs b/frontend/src/app/main/ui/workspace/shapes/path/editor.cljs
index f660d9334..56189d104 100644
--- a/frontend/src/app/main/ui/workspace/shapes/path/editor.cljs
+++ b/frontend/src/app/main/ui/workspace/shapes/path/editor.cljs
@@ -300,11 +300,12 @@
         (mf/with-memo [content-points]
           (into #{} content-points))
 
-        last-p (->> content last path.helpers/segment->point)
+        last-p
+        (->> content last path.helpers/segment->point)
 
         handlers
         (mf/with-memo [content]
-          (path.segment/content->handlers content))
+          (path.segment/get-handlers content))
 
         is-path-start
         (not (some? last-point))