Add liblutok a lightweight C++ API for lua.

It is added an INTERNALLIB and not installed.  It will be used by kyua.

This is a preparatory commit for D24103.

Reviewed by:	emaste
Obtained from:	CheriBSD
Sponsored by:	DARPA

1 files changed, 71 insertions, 0 deletions

diff --git a/contrib/lutok/c_gate.hpp b/contrib/lutok/c_gate.hpp
new file mode 100644
index 000000000000..36bc9c228f84
--- /dev/null
+++ b/contrib/lutok/c_gate.hpp
@@ -0,0 +1,71 @@
+// Copyright 2011 Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+//   notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright
+//   notice, this list of conditions and the following disclaimer in the
+//   documentation and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors
+//   may be used to endorse or promote products derived from this software
+//   without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+/// \file c_gate.hpp
+/// Provides direct access to the C state of the Lua wrappers.
+
+#if !defined(LUTOK_C_GATE_HPP)
+#define LUTOK_C_GATE_HPP
+
+#include <lua.hpp>
+
+namespace lutok {
+
+
+class state;
+
+
+/// Gateway to the raw C state of Lua.
+///
+/// This class provides a mechanism to muck with the internals of the state
+/// wrapper class.  Client code may wish to do so if Lutok is missing some
+/// features of the performance of Lutok in a particular situation is not
+/// reasonable.
+///
+/// \warning The use of this class is discouraged.  By using this class, you are
+/// entering the world of unsafety.  Anything you do through the objects exposed
+/// through this class will not be controlled by RAII patterns not validated in
+/// any other way, so you can end up corrupting the Lua state and later get
+/// crashes on otherwise perfectly-valid C++ code.
+class state_c_gate {
+    /// The C++ state that this class wraps.
+    state& _state;
+
+public:
+    state_c_gate(state&);
+    ~state_c_gate(void);
+
+    static state connect(lua_State*);
+
+    lua_State* c_state(void);
+};
+
+
+}  // namespace lutok
+
+#endif  // !defined(LUTOK_C_GATE_HPP)