Fixes memory leaks in the eventhandler

runtime/bin/eventhandler.h

Index: runtime/bin/eventhandler.h
diff --git a/runtime/bin/eventhandler.h b/runtime/bin/eventhandler.h
index ab5b590b65112c7cb28643df413ff7be28d3aae1..02cf0792e9b7f2b25a1688ff62fa0a39d063a41e 100644
--- a/runtime/bin/eventhandler.h
+++ b/runtime/bin/eventhandler.h
@@ -132,6 +132,8 @@ class CircularLinkedList {
  public:
   CircularLinkedList() : head_(NULL) {}
 
+  typedef void (*ClearFun) (void* value);
+
   // Returns true if the list was empty.
   bool Add(T t) {
     Entry* e = new Entry(t);
@@ -195,8 +197,12 @@ class CircularLinkedList {
     }
   }
 
-  void RemoveAll() {
+  void RemoveAll(ClearFun clear = NULL) {
     while (HasHead()) {
+      if (clear != NULL) {
+        T h = head();
+        clear(reinterpret_cast<void*>(h));
+      }
       RemoveHead();

[siva, 2016/08/09 21:41:43]

Wouldn't it be more atomic to pass the clear function down to RemoveHead and
invoke it after head is removed from the list.

There seems to be no locks around this not sure if multiple threads can access
the list and see an entry is an inconsistent state because it still is in the
list but the PortEntry has been deleted.

[zra, 2016/08/09 22:19:27]

Done. The DescriptorInfos and therefore the CircularLinkedList of active readers
are only touched by the event handler thread, AFAIU.

     }
   }
@@ -413,7 +419,9 @@ class DescriptorInfoMultipleMixin : public DI {
       : DI(fd), tokens_map_(&SamePortValue, kTokenCount),
         disable_tokens_(disable_tokens) {}
 
-  virtual ~DescriptorInfoMultipleMixin() {}
+  virtual ~DescriptorInfoMultipleMixin() {
+    RemoveAllPorts();
+  }
 
   virtual bool IsListeningSocket() const { return true; }
 
@@ -497,14 +505,16 @@ class DescriptorInfoMultipleMixin : public DI {
   }
 
   virtual void RemoveAllPorts() {
-    active_readers_.RemoveAll();
     for (HashMap::Entry *entry = tokens_map_.Start();
          entry != NULL;
          entry = tokens_map_.Next(entry)) {
       PortEntry* pentry = reinterpret_cast<PortEntry*>(entry->value);
+      entry->value = NULL;
+      active_readers_.Remove(pentry);
       delete pentry;
     }
     tokens_map_.Clear();
+    active_readers_.RemoveAll(DeletePortEntry);
   }
 
   virtual Dart_Port NextNotifyDartPort(intptr_t events_ready) {
@@ -585,6 +595,11 @@ class DescriptorInfoMultipleMixin : public DI {
   }
 
  private:
+  static void DeletePortEntry(void* data) {
+    PortEntry* entry = reinterpret_cast<PortEntry*>(data);
+    delete entry;
+  }
+
   // The [Dart_Port]s which are not paused (i.e. are interested in read events,
   // i.e. `mask == (1 << kInEvent)`) and we have enough tokens to communicate
   // with them.