Kotlin multiplatform leaking memory (#4037)

* Add deinit for KMP iOS and JVM targets

* Add deinit for JS target

* Add deinit for JS target

* Fix JVM native name

* Reuse one thread on JVM

---------

Co-authored-by: satoshiotomakan <[email protected]>

Author: vcoolish

codegen/lib/templates/kotlin/android_class.erb

@@ -9,6 +9,9 @@ actual class <%= entity.name %> private constructor(
 
     init {
         if (nativeHandle == 0L) throw IllegalArgumentException()
+<%  unless entity.methods.select{ |x| x.name == "Delete" }.empty? -%>
+        GenericPhantomReference.register(this, nativeHandle, ::delete)
+<%  end -%>
     }
 <%# Constructors -%>
 <%- constructors.each do |constructor| -%>
@@ -52,6 +55,12 @@ actual class <%= entity.name %> private constructor(
         @JvmStatic
         @JvmName("createFromNative")
         private fun createFromNative(nativeHandle: Long) = <%= entity.name %>(nativeHandle)
+
+<%  unless entity.methods.select{ |x| x.name == "Delete" }.empty? -%>
+        @JvmStatic
+        @JvmName("delete")
+        private external fun delete(handle: Long)
+<%- end -%>
 <%- constructors.each do |constructor| -%>
 
         @JvmStatic

codegen/lib/templates/kotlin/ios_class.erb

@@ -9,6 +9,12 @@ import kotlinx.cinterop.CPointer
 actual class <%= entity.name %> constructor(
     val pointer: CPointer<TW<%= entity.name %>>,
 ) {
+<%  unless entity.methods.select{ |x| x.name == "Delete" }.empty? -%>
+    @OptIn(ExperimentalStdlibApi::class)
+    private val cleaner = kotlin.native.internal.createCleaner(pointer) { ptr ->
+        TW<%= entity.name %>Delete(ptr)
+    }
+<%  end -%>
 <%# Constructors -%>
 <%- constructors.each do |constructor| -%>
 

codegen/lib/templates/kotlin/js_accessors_class.erb

@@ -8,6 +8,9 @@ external interface Js<%= entity.name %> {
 <%- entity.properties.each do |property| -%>
     fun <%= KotlinHelper.fix_name(WasmCppHelper.format_name(property.name)) %>()<%= KotlinHelper.js_return_type(property.return_type) %>
 <%- end -%>
+<%  unless entity.methods.select{ |x| x.name == "Delete" }.empty? -%>
+    fun delete()
+<% end -%>
 <% entity.methods.each do |method| -%>
 <%   next if method.name == "Delete" -%>
     fun <%= KotlinHelper.fix_name(WasmCppHelper.format_name(method.name)) %>(<%= KotlinHelper.js_parameters(method.parameters.drop(1)) %>)<%= KotlinHelper.js_return_type(method.return_type) %>

codegen/lib/templates/kotlin/js_class.erb

@@ -6,6 +6,21 @@
 actual class <%= entity.name %> constructor(
     val jsValue: Js<%= entity.name %>,
 ) {
+<%  unless entity.methods.select{ |x| x.name == "Delete" }.empty? -%>
+    private val finalizationRegistry =
+        js(
+            """
+                new FinalizationRegistry(function(heldValue) {
+                    heldValue.delete();
+                })
+            """
+        )
+
+    init {
+        finalizationRegistry.register(this, jsValue)
+    }
+<% end -%>
+
 <%# Constructors -%>
 <%- constructors.each do |constructor| -%>
 

kotlin/wallet-core-kotlin/src/commonAndroidJvmMain/kotlin/com/trustwallet/core/GenericPhantomReference.kt

@@ -0,0 +1,47 @@
+package com.trustwallet.core
+
+import java.lang.ref.PhantomReference
+import java.lang.ref.ReferenceQueue
+
+internal class GenericPhantomReference private constructor(
+    referent: Any,
+    private val handle: Long,
+    private val onDelete: (Long) -> Unit,
+) : PhantomReference<Any>(referent, queue) {
+
+    companion object {
+        private val references: MutableSet<GenericPhantomReference> = HashSet()
+        private val queue: ReferenceQueue<Any> = ReferenceQueue()
+
+        init {
+            Thread {
+                try {
+                    doDeletes()
+                } catch (e: InterruptedException) {
+                    Thread.currentThread().interrupt()
+                }
+            }.apply {
+                name = "WCFinalizingDaemon"
+                isDaemon = true
+                priority = Thread.NORM_PRIORITY
+                start()
+            }
+        }
+
+        fun register(
+            referent: Any,
+            handle: Long,
+            onDelete: (Long) -> Unit,
+        ) {
+            references.add(GenericPhantomReference(referent, handle, onDelete))
+        }
+
+        private fun doDeletes() {
+            while (true) {
+                val ref = queue.remove() as GenericPhantomReference
+                ref.onDelete(ref.handle)
+                references.remove(ref)
+            }
+        }
+    }
+}