[NaCl SDK} Add EventListener and EventEmitter to support epoll.

native_client_sdk/src/libraries/nacl_io/kernel_handle.cc

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "nacl_io/kernel_handle.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <pthread.h>
 
 #include "nacl_io/mount.h"
 #include "nacl_io/mount_node.h"
 #include "nacl_io/osunistd.h"
 
 #include "sdk_util/auto_lock.h"
 
 // It is only legal to construct a handle while the kernel lock is held.
 KernelHandle::KernelHandle()
     : mount_(NULL), node_(NULL), offs_(0) {}
 
 KernelHandle::KernelHandle(const ScopedMount& mnt, const ScopedMountNode& node)
     : mount_(mnt), node_(node), offs_(0) {}
 
+KernelHandle::~KernelHandle() {
+  // Force release order, so that mount persists beyond node
+  node_.reset(NULL);
+  mount_.reset(NULL);
+}
+
 Error KernelHandle::Init(int open_mode) {
   if (open_mode & O_APPEND) {
     size_t node_size;
     Error error = node_->GetSize(&offs_);
     if (error)
       return error;
   }
 
   return 0;
 }
@@ skipping 59 matching lines @@
 Error KernelHandle::GetDents(struct dirent* pdir, size_t nbytes, int* cnt) {
   AUTO_LOCK(offs_lock_);
   Error error = node_->GetDents(offs_, pdir, nbytes, cnt);
   if (0 == error)
     offs_ += *cnt;
   return error;
 }
 
 const ScopedRef<MountNode>& KernelHandle::node() { return node_; }
 const ScopedRef<Mount>& KernelHandle::mount() { return mount_; }