Replace manual handle memory management with GC allocated space (#2)

Author: WojciechMazur

build.sbt

@@ -40,7 +40,6 @@ lazy val commonSettings = Seq(
   ),
   libraryDependencies += "com.lihaoyi" %%% "utest" % "0.8.3" % Test,
   testFrameworks += new TestFramework("utest.runner.Framework"),
-  nativeConfig ~= {_.withMultithreading(false)},
 )
 
 lazy val core = project

core/src/main/scala/scala/scalanative/loop/Poll.scala

@@ -1,38 +1,40 @@
 package scala.scalanative.loop
 
-import scala.scalanative.libc.stdlib
 import LibUV._, LibUVConstants._
-import scala.scalanative.unsafe.Ptr
+import scala.scalanative.unsafe.{Ptr, sizeOf}
+import scala.scalanative.runtime.BlobArray
 import internals.HandleUtils
 
 class RWResult(val result: Int, val readable: Boolean, val writable: Boolean)
-@inline class Poll(val ptr: Ptr[Byte]) extends AnyVal {
+@inline class Poll(private val data: BlobArray) extends AnyVal {
+  private def handle: Ptr[Byte] = data.atUnsafe(0)
+
   def start(in: Boolean, out: Boolean)(callback: RWResult => Unit): Unit = {
-    HandleUtils.setData(ptr, callback)
+    HandleUtils.setData(handle, callback)
     var events = 0
     if (out) events |= UV_WRITABLE
     if (in) events |= UV_READABLE
-    uv_poll_start(ptr, events, Poll.pollReadWriteCB)
+    uv_poll_start(handle, events, Poll.pollReadWriteCB)
   }
 
   def startReadWrite(callback: RWResult => Unit): Unit = {
-    HandleUtils.setData(ptr, callback)
-    uv_poll_start(ptr, UV_READABLE | UV_WRITABLE, Poll.pollReadWriteCB)
+    HandleUtils.setData(handle, callback)
+    uv_poll_start(handle, UV_READABLE | UV_WRITABLE, Poll.pollReadWriteCB)
   }
 
   def startRead(callback: Int => Unit): Unit = {
-    HandleUtils.setData(ptr, callback)
-    uv_poll_start(ptr, UV_READABLE, Poll.pollReadCB)
+    HandleUtils.setData(handle, callback)
+    uv_poll_start(handle, UV_READABLE, Poll.pollReadCB)
   }
 
   def startWrite(callback: Int => Unit): Unit = {
-    HandleUtils.setData(ptr, callback)
-    uv_poll_start(ptr, UV_WRITABLE, Poll.pollWriteCB)
+    HandleUtils.setData(handle, callback)
+    uv_poll_start(handle, UV_WRITABLE, Poll.pollWriteCB)
   }
 
   def stop(): Unit = {
-    uv_poll_stop(ptr)
-    HandleUtils.close(ptr)
+    uv_poll_stop(handle)
+    HandleUtils.close(handle)
   }
 }
 
@@ -72,8 +74,10 @@ object Poll {
   private lazy val size = uv_handle_size(UV_POLL_T)
 
   def apply(fd: Int): Poll = {
-    val pollHandle = stdlib.malloc(size)
-    uv_poll_init(EventLoop.loop, pollHandle, fd)
-    new Poll(pollHandle)
+    // GC managed memory, but scans only user data 
+    val data = BlobArray.alloc(size.toInt)
+    data.setScannableLimitUnsafe(sizeOf[Ptr[_]])
+    uv_poll_init(EventLoop.loop, data.atUnsafe(0), fd)
+    new Poll(data)
   }
 }

core/src/main/scala/scala/scalanative/loop/Timer.scala

@@ -1,13 +1,14 @@
 package scala.scalanative.loop
 
-import scala.scalanative.libc.stdlib
 import scala.concurrent.{Future, Promise}
 import scala.concurrent.duration._
 import LibUV._, LibUVConstants._
-import scala.scalanative.unsafe.Ptr
+import scala.scalanative.unsafe.{Ptr, sizeOf}
+import scala.scalanative.runtime.BlobArray
 import internals.HandleUtils
 
-@inline final class Timer private (private val ptr: Ptr[Byte]) extends AnyVal {
+@inline final class Timer private (private val data: BlobArray) extends AnyVal {
+  private def ptr = data.atUnsafe(0)
   def clear(): Unit = {
     uv_timer_stop(ptr)
     HandleUtils.close(ptr)
@@ -29,17 +30,21 @@ object Timer {
       repeat: Long,
       callback: () => Unit
   ): Timer = {
-    val timerHandle = stdlib.malloc(uv_handle_size(UV_TIMER_T))
+    // GC managed memory, but scans only user data
+    val data = BlobArray.alloc(uv_handle_size(UV_TIMER_T).toInt)
+    data.setScannableLimitUnsafe(sizeOf[Ptr[_]])
+
+    val timerHandle = data.atUnsafe(0)
     uv_timer_init(EventLoop.loop, timerHandle)
-    HandleUtils.setData(timerHandle, callback)
-    val timer = new Timer(timerHandle)
+    val timer = new Timer(data)
     val withClearIfTimeout: () => Unit =
       if (repeat == 0L) { () =>
         {
           callback()
           timer.clear()
         }
       } else callback
+    HandleUtils.setData(timerHandle, withClearIfTimeout)
     uv_timer_start(timerHandle, timeoutCB, timeout, repeat)
     timer
   }

core/src/main/scala/scala/scalanative/loop/internals/HandleUtils.scala

@@ -4,12 +4,9 @@ package internals
 import scala.scalanative.runtime._
 import scala.scalanative.runtime.Intrinsics._
 import scala.scalanative.unsafe.Ptr
-import scala.scalanative.libc.stdlib
 import LibUV._
 
 private[loop] object HandleUtils {
-  private val references = new java.util.IdentityHashMap[Object, Int]()
-
   @inline def getData[T <: Object](handle: Ptr[Byte]): T = {
     // data is the first member of uv_loop_t
     val ptrOfPtr = handle.asInstanceOf[Ptr[Ptr[Byte]]]
@@ -24,23 +21,16 @@ private[loop] object HandleUtils {
     // data is the first member of uv_loop_t
     val ptrOfPtr = handle.asInstanceOf[Ptr[Ptr[Byte]]]
     if (obj != null) {
-      references.put(obj, references.get(obj) + 1)
       val rawptr = castObjectToRawPtr(obj)
       !ptrOfPtr = fromRawPtr[Byte](rawptr)
     } else {
       !ptrOfPtr = null
     }
   }
-  private val onCloseCB: CloseCB = (handle: UVHandle) => {
-    stdlib.free(handle)
-  }
   @inline def close(handle: Ptr[Byte]): Unit = {
-    if (getData(handle) != null) {
-      uv_close(handle, onCloseCB)
-      val data    = getData[Object](handle)
-      val current = references.get(data)
-      if (current > 1) references.put(data, current - 1)
-      else references.remove(data)
+    val data = getData[Object](handle)
+    if (data != null) {
+      uv_close(handle, null)
       setData(handle, null)
     }
   }