From fbca7ab99c84d93a28f7773f1c56be12e1a939a3 Mon Sep 17 00:00:00 2001
From: Nathan Marz <nathan@nathanmarz.com>
Date: Tue, 31 May 2016 23:04:24 -0400
Subject: [PATCH] stop using ConcurrentHashMap for inline cache, instead intern
 a new var at macro-time. 17% performance improvement for [:a :b :c] benchmark

---
 src/clj/com/rpl/specter/impl.cljx  | 11 -----------
 src/clj/com/rpl/specter/macros.clj | 20 +++++++-------------
 2 files changed, 7 insertions(+), 24 deletions(-)

diff --git a/src/clj/com/rpl/specter/impl.cljx b/src/clj/com/rpl/specter/impl.cljx
index d443009..1012908 100644
--- a/src/clj/com/rpl/specter/impl.cljx
+++ b/src/clj/com/rpl/specter/impl.cljx
@@ -724,23 +724,12 @@
    params-maker ; can be null
    ])
 
-#+clj
-(defonce PATH-CACHE (java.util.concurrent.ConcurrentHashMap.))
-
 (def MUST-CACHE-PATHS (mutable-cell false))
 
 (defn must-cache-paths!
   ([] (must-cache-paths! true))
   ([v] (set-cell! MUST-CACHE-PATHS v)))
 
-#+clj
-(defn add-path-cache! [k v]
-  (.put ^java.util.concurrent.ConcurrentHashMap PATH-CACHE k v))
-
-#+clj
-(defn get-path-cache [^String k]
-  (.get ^java.util.concurrent.ConcurrentHashMap PATH-CACHE k))
-
 (defn- extract-original-code [p]
   (cond
     (instance? LocalSym p) (:sym p)
diff --git a/src/clj/com/rpl/specter/macros.clj b/src/clj/com/rpl/specter/macros.clj
index 9b7a077..15301de 100644
--- a/src/clj/com/rpl/specter/macros.clj
+++ b/src/clj/com/rpl/specter/macros.clj
@@ -435,29 +435,21 @@
         prepared-path (ic-prepare-path local-syms expanded)
         possible-params (vec (ic-possible-params expanded))
 
-        ;; TODO: unclear if using long here versus string makes
-        ;; a significant difference
-        ;; - but using random longs creates possibility of collisions
-        ;; (birthday problem)
-        ;; - ideally could have a real inline cache that wouldn't
-        ;; have to do any hashing/equality checking at all
         ;; - with invokedynamic here, could go directly to the code
         ;; to invoke and/or parameterize the precompiled path without
         ;; a bunch of checks beforehand
-        cache-id (if (= platform :clj) (i/gen-uuid-str))
-        cache-sym (if (= platform :cljs)
-                    (vary-meta
-                      (gensym "pathcache")
-                      assoc :cljs.analyzer/no-resolve true))
+        cache-sym (vary-meta
+                    (gensym "pathcache")
+                      assoc :cljs.analyzer/no-resolve true)
 
         info-sym (gensym "info")
 
         get-cache-code (if (= platform :clj)
-                         `(i/get-path-cache ~cache-id)
+                         `(i/get-cell ~cache-sym)
                          cache-sym
                          )
         add-cache-code (if (= platform :clj)
-                         `(i/add-path-cache! ~cache-id ~info-sym)
+                         `(i/set-cell! ~cache-sym ~info-sym)
                          `(def ~cache-sym ~info-sym))
 
 
@@ -473,6 +465,8 @@
              ~(mapv (fn [p] `(fn [] ~p)) possible-params)
              ))
         ]
+    (if (= platform :clj)
+      (intern *ns* cache-sym (i/mutable-cell)))
     `(let [info# ~get-cache-code
            
            ^com.rpl.specter.impl.CachedPathInfo info#