From 51cfc819be07922236923108e7c0892d2fcf7304 Mon Sep 17 00:00:00 2001
From: Mikhail Kuzmin <m.kuzmin@darkleaf.ru>
Date: Wed, 16 Oct 2024 21:17:13 +0400
Subject: [PATCH] Add log middleware

---
 src/darkleaf/di/core.clj                 | 16 ++++++++++
 test/darkleaf/di/tutorial/x_log_test.clj | 37 ++++++++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 test/darkleaf/di/tutorial/x_log_test.clj

diff --git a/src/darkleaf/di/core.clj b/src/darkleaf/di/core.clj
index 58c0018a..cb8f4c6f 100644
--- a/src/darkleaf/di/core.clj
+++ b/src/darkleaf/di/core.clj
@@ -784,3 +784,19 @@
                ~@body))
            (finally
              (.close resource#)))))))
+
+(defn log [built-cb demolished-cb]
+  (fn [registry]
+    (fn [key]
+      (let [factory (registry key)]
+        (reify p/Factory
+          (dependencies [_]
+            (p/dependencies factory))
+          (build [_ deps]
+            (let [obj (p/build factory deps)]
+              (built-cb key deps obj)
+              obj))
+          (demolish [_ obj]
+            (p/demolish factory obj)
+            (demolished-cb key obj)
+            nil))))))
diff --git a/test/darkleaf/di/tutorial/x_log_test.clj b/test/darkleaf/di/tutorial/x_log_test.clj
new file mode 100644
index 00000000..938aa8ce
--- /dev/null
+++ b/test/darkleaf/di/tutorial/x_log_test.clj
@@ -0,0 +1,37 @@
+(ns darkleaf.di.tutorial.x-log-test
+  (:require
+   [clojure.test :as t]
+   [darkleaf.di.core :as di]))
+
+(defn a
+  {::di/kind :component}
+  []
+  :a)
+
+(defn b [{a `a}]
+  :b)
+
+(defn c
+  {::di/kind :component}
+  [{b `b}]
+  :c)
+
+(t/deftest log
+  (let [logs         (atom [])
+        built!       (fn [key deps obj]
+                       (swap! logs conj [:built key deps obj]))
+        demolished!  (fn [key obj]
+                       (swap! logs conj [:demolished key obj]))
+        [a b c
+         :as system] (di/start [`a `b `c]
+                               (di/log built! demolished!))]
+    (di/stop system)
+    (t/is (= [[:built `a {} a]
+              [:built `b {`a a} b]
+              [:built `c {`b b} c]
+              [:built ::di/implicit-root {`a a `b b `c c} [a b c]]
+              [:demolished ::di/implicit-root [a b c]]
+              [:demolished `c c]
+              [:demolished `b b]
+              [:demolished `a a]]
+             @logs))))