Destructors

README.md

@@ -28,8 +28,8 @@ class Shape:
     method init() =
         echo "Creating a Shape"
 
-    ## Optional destructor (not implemented yet)
-    method destroy() =
+    ## Optional destructor (not supported in JS)
+    method deinit() =
         echo "Destroying a Shape"
 
     ## Abstract draw function

classes.nimble

@@ -1,5 +1,5 @@
 # Package
-version       = "0.2.15"
+version       = "0.3.16"
 author        = "jjv360"
 description   = "Adds class support to Nim."
 license       = "MIT"

src/classes.nim

@@ -11,7 +11,7 @@ import ./classes/plugin_super
 import ./classes/plugin_meta
 import ./classes/plugin_mixins
 import ./classes/plugin_singleton
-# import ./classes/plugin_destructors
+import ./classes/plugin_destructors
 export static
 
 ## Class definition

src/classes/plugin_destructors.nim

@@ -18,13 +18,15 @@ proc generateDestructor(classDef : ClassDescription) =
     if not m.existsIn(classDef):
         return
 
-    # It exists, add destroy method
-    let thisName = ident"this"
+    # It exists, add destroy proc.
+    # Note: The way this works is that we receive a reference to the actual underlying object, unwrapped from
+    # any refs. So we need to wrap it again for the final deinit call.
     let methodName = parseExpr("`=destroy`")
     let className = classDef.name
     classDef.outputBody.insert(0, quote do:
-        proc `methodName`*(`thisName`: var typeof(`className`()[])) =
-            `thisName`.deinit()
+        proc `methodName`*(thisRaw: var typeof(`className`()[])) =
+            var this : `className` = cast[`className`](thisRaw.addr)
+            this.deinit()
     )
 
 

test.nim

@@ -20,6 +20,8 @@ else:
     # Native code
     import asyncdispatch
     import terminal
+    import os
+    import times
 
     const platformName = "native"
 
@@ -108,7 +110,7 @@ assert(externalGetterSetter.testCustomSetter == 8)
 
 
 
-group "Constructors"
+group "Constructors and destructors"
 test "Automatic constructors on the base class"
 class ClassA
 
@@ -211,33 +213,47 @@ class ClassWithFactory:
 assert(ClassWithFactory.withValue(3).v1 == 3)
 
 
-test "Destructor called"
+test "Destructors"
 
-# # Counter to store destructor call count
-# var globalDestructorCounter = 1
-
-# # Simple destructor
-# class TestDestructor1:
-#     method deinit() = globalDestructorCounter += 1
-
-# # Class with destructor in the superclass
-# class TestDestructor2 of TestDestructor1
+when defined(js):
 
-# # Class with custom destructor
-# class TestDestructor3 of TestDestructor1:
-#     method deinit() = 
-#         super.deinit()
-#         globalDestructorCounter += 1    # <-- Add again
+    # Not supported
+    warn "Not supported in Javascript"
 
-# # Run all destructors
-# proc checkDestructor() =
-#     let cls = TestDestructor1.init()    # <-- Destructor adds one
-#     discard TestDestructor2.init()      # <-- Destructor in superclass adds one
-#     discard TestDestructor3.init()      # <-- Destructor adds one + calls super destructor which also adds one
-# checkDestructor()
+else:
 
-# # Ensure the counter is correct
-# assert(globalDestructorCounter == 5)
+    # Counter to store destructor call count
+    var globalDestructorCounter = 1
+
+    # Simple destructor
+    class TestDestructor1:
+        method deinit() = globalDestructorCounter += 1
+
+    # Class with destructor in the superclass
+    class TestDestructor2 of TestDestructor1
+
+    # Class with custom destructor
+    class TestDestructor3 of TestDestructor1:
+        method deinit() = 
+            super.deinit()
+            globalDestructorCounter += 1    # <-- Add again
+
+    # Create objects to be cleaned up
+    proc checkDestructor() =
+        let cls = TestDestructor1.init()    # <-- Destructor adds one
+        let cls2 = TestDestructor2.init()      # <-- Destructor in superclass adds one
+        let cls3 = TestDestructor3.init()      # <-- Destructor adds one + calls super destructor which also adds one
+    checkDestructor()
+
+    # GC takes a while, wait for it to be done
+    let startedAt = cpuTime()
+    while true:
+        if globalDestructorCounter == 5 or startedAt - cpuTime() > 10: break
+        GC_fullCollect()
+        sleep(100)
+
+    # Ensure the counter is correct
+    assert(globalDestructorCounter == 5, "Expected 5 but got " & $globalDestructorCounter)