Fix handling of free descriptors when calling dup2.

native_client_sdk/src/libraries/nacl_io/kernel_object.cc

Index: native_client_sdk/src/libraries/nacl_io/kernel_object.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/kernel_object.cc b/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
index 8c670f8f789f89dc91cf41755e817dc351a1c3d2..93b2f9a1d5b072e82bb110812a84876a8480a122 100644
--- a/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
+++ b/native_client_sdk/src/libraries/nacl_io/kernel_object.cc
@@ -253,8 +253,15 @@ void KernelObject::FreeAndReassignFD(int fd,
     AUTO_LOCK(handle_lock_);
 
     // If the required FD is larger than the current set, grow the set
-    if (fd >= (int)handle_map_.size())
+    if (fd >= (int)handle_map_.size()) {

[binji, 2014/12/12 18:55:20]

use c++-style cast

[bradn, 2014/12/12 22:58:18]

Done.

+      int sz = (int)handle_map_.size();

[Sam Clegg, 2014/12/12 00:44:40]

Move this line outside the condition to avoid calling .size() twice?

[bradn, 2014/12/12 22:58:18]

Done.

       handle_map_.resize(fd + 1);

[Sam Clegg, 2014/12/12 00:44:40]

A comment here to describe what is happening and why it might happen?

[bradn, 2014/12/12 22:58:18]

Done.

+      for (; sz < fd; ++sz) {
+        free_fds_.push_back(sz);
+        std::push_heap(free_fds_.begin(), free_fds_.end(),
+                       std::greater<int>());
+      }
+    }
 
     // This path will be from an existing handle, and absolute.
     handle_map_[fd] = Descriptor_t(handle, path);