Somewhat experimental fix for memory leaks seen in Microcontrollers. If you notice any new issues after this, please do let me know.

This essentially schedules machines for full cleanup at a later point, to allow executor threads to finish (can't close states while they're running, don't want to wait for them to finish to avoid lagging servers).

src/main/scala/li/cil/oc/common/EventHandler.scala

@@ -22,6 +22,7 @@ import li.cil.oc.common.tileentity.traits.power
 import li.cil.oc.integration.Mods
 import li.cil.oc.integration.util
 import li.cil.oc.server.component.Keyboard
+import li.cil.oc.server.machine.Machine
 import li.cil.oc.server.{PacketSender => ServerPacketSender}
 import li.cil.oc.util._
 import net.minecraft.client.Minecraft
@@ -49,12 +50,16 @@ object EventHandler {
 
   private val keyboards = java.util.Collections.newSetFromMap[Keyboard](new java.util.WeakHashMap[Keyboard, java.lang.Boolean])
 
+  private val machines = mutable.Set.empty[Machine]
+
   def onRobotStart(robot: Robot): Unit = runningRobots += robot
 
   def onRobotStopped(robot: Robot): Unit = runningRobots -= robot
 
   def addKeyboard(keyboard: Keyboard): Unit = keyboards += keyboard
 
+  def scheduleClose(machine: Machine) = machines += machine
+
   def schedule(tileEntity: TileEntity) {
     if (SideTracker.isServer) pending.synchronized {
       pending += (() => Network.joinOrCreateNetwork(tileEntity))
@@ -130,6 +135,10 @@ object EventHandler {
       else if (robot.world != null) robot.machine.update()
     })
     runningRobots --= invalid
+
+    val closed = mutable.ArrayBuffer.empty[Machine]
+    machines.foreach(machine => if (machine.tryClose()) closed += machine)
+    machines --= closed
   }
 
   @SubscribeEvent
@@ -243,7 +252,7 @@ object EventHandler {
 
     didRecraft = recraft(e, tablet, stack => {
       // Restore EEPROM currently used in tablet.
-      new TabletData(stack).items.collect { case Some(item) => item}.find(api.Items.get(_) == eeprom)
+      new TabletData(stack).items.collect { case Some(item) => item }.find(api.Items.get(_) == eeprom)
     }) || didRecraft
 
     // Presents?

src/main/scala/li/cil/oc/common/tileentity/traits/Computer.scala

@@ -127,6 +127,11 @@ trait Computer extends Environment with ComponentInventory with Rotatable with B
     ServerPacketSender.sendComputerState(this)
   }
 
+  override def dispose(): Unit = {
+    super.dispose()
+    if (machine != null) machine.stop()
+  }
+
   // ----------------------------------------------------------------------- //
 
   override def readFromNBTForServer(nbt: NBTTagCompound) {

src/main/scala/li/cil/oc/server/machine/Machine.scala

@@ -23,6 +23,7 @@ import li.cil.oc.api.network.Message
 import li.cil.oc.api.network.Node
 import li.cil.oc.api.network.Visibility
 import li.cil.oc.api.prefab
+import li.cil.oc.common.EventHandler
 import li.cil.oc.common.SaveHandler
 import li.cil.oc.common.Slot
 import li.cil.oc.common.tileentity
@@ -257,6 +258,7 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
       false
     case _ =>
       state.push(Machine.State.Stopping)
+      EventHandler.scheduleClose(this)
       true
   })
 
@@ -392,6 +394,8 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
 
   // ----------------------------------------------------------------------- //
 
+  def isExecuting = state.synchronized(state.contains(Machine.State.Running))
+
   override val canUpdate = true
 
   override def update() = if (state.synchronized(state.top != Machine.State.Stopped)) {
@@ -514,7 +518,7 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
           inSynchronizedCall = false
         }
 
-        assert(state.top != Machine.State.Running)
+        assert(!isExecuting)
       case _ => // Nothing special to do, just avoid match errors.
     })
 
@@ -643,7 +647,7 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
 
     super.load(nbt)
 
-    state.pushAll(nbt.getIntArray("state").reverse.map(Machine.State(_)))
+    state.pushAll(nbt.getIntArray("state").reverseMap(Machine.State(_)))
     nbt.getTagList("users", NBT.TAG_STRING).foreach((tag: NBTTagString) => _users += tag.func_150285_a_())
     if (nbt.hasKey("message")) {
       message = Some(nbt.getString("message"))
@@ -703,7 +707,7 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
   }
 
   override def save(nbt: NBTTagCompound): Unit = Machine.this.synchronized {
-    assert(state.top != Machine.State.Running) // Lock on 'this' should guarantee this.
+    assert(!isExecuting) // Lock on 'this' should guarantee this.
 
     // Make sure we don't continue running until everything has saved.
     pause(0.05)
@@ -798,16 +802,25 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
     false
   }
 
+  def tryClose(): Boolean =
+    if (isExecuting) false
+    else {
+      close()
+      true
+    }
+
   private def close() = state.synchronized(
     if (state.size == 0 || state.top != Machine.State.Stopped) {
-      state.clear()
-      state.push(Machine.State.Stopped)
-      Option(architecture).foreach(_.close())
-      signals.clear()
-      uptime = 0
-      cpuTotal = 0
-      cpuStart = 0
-      remainIdle = 0
+      this.synchronized {
+        state.clear()
+        state.push(Machine.State.Stopped)
+        Option(architecture).foreach(_.close())
+        signals.clear()
+        uptime = 0
+        cpuTotal = 0
+        cpuStart = 0
+        remainIdle = 0
+      }
 
       // Mark state change in owner, to send it to clients.
       host.markChanged()
@@ -909,7 +922,7 @@ class Machine(val host: MachineHost) extends prefab.ManagedEnvironment with mach
           case Machine.State.Stopping => // Nothing to do, we'll die anyway.
           case _ => throw new AssertionError("Invalid state in executor post-processing.")
         }
-        assert(state.top != Machine.State.Running)
+        assert(!isExecuting)
       }
     }
     catch {