Imported existing code

libraries/include/boost/asio/detail/call_stack.hpp

@@ -0,0 +1,92 @@
+//
+// call_stack.hpp
+// ~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BOOST_ASIO_DETAIL_CALL_STACK_HPP
+#define BOOST_ASIO_DETAIL_CALL_STACK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/push_options.hpp>
+
+#include <boost/asio/detail/noncopyable.hpp>
+#include <boost/asio/detail/tss_ptr.hpp>
+
+namespace boost {
+namespace asio {
+namespace detail {
+
+// Helper class to determine whether or not the current thread is inside an
+// invocation of io_service::run() for a specified io_service object.
+template <typename Owner>
+class call_stack
+{
+public:
+  // Context class automatically pushes an owner on to the stack.
+  class context
+    : private noncopyable
+  {
+  public:
+    // Push the owner on to the stack.
+    explicit context(Owner* d)
+      : owner_(d),
+        next_(call_stack<Owner>::top_)
+    {
+      call_stack<Owner>::top_ = this;
+    }
+
+    // Pop the owner from the stack.
+    ~context()
+    {
+      call_stack<Owner>::top_ = next_;
+    }
+
+  private:
+    friend class call_stack<Owner>;
+
+    // The owner associated with the context.
+    Owner* owner_;
+
+    // The next element in the stack.
+    context* next_;
+  };
+
+  friend class context;
+
+  // Determine whether the specified owner is on the stack.
+  static bool contains(Owner* d)
+  {
+    context* elem = top_;
+    while (elem)
+    {
+      if (elem->owner_ == d)
+        return true;
+      elem = elem->next_;
+    }
+    return false;
+  }
+
+private:
+  // The top of the stack of calls for the current thread.
+  static tss_ptr<context> top_;
+};
+
+template <typename Owner>
+tss_ptr<typename call_stack<Owner>::context>
+call_stack<Owner>::top_;
+
+} // namespace detail
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#endif // BOOST_ASIO_DETAIL_CALL_STACK_HPP