1// Copyright 2011 Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above copyright 11// notice, this list of conditions and the following disclaimer in the 12// documentation and/or other materials provided with the distribution. 13// * Neither the name of Google Inc. nor the names of its contributors 14// may be used to endorse or promote products derived from this software 15// without specific prior written permission. 16// 17// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29/// \file stack_cleaner.hpp 30/// Provides the stack_cleaner class. 31 32#if !defined(LUTOK_STACK_CLEANER_HPP) 33#define LUTOK_STACK_CLEANER_HPP 34 35#include <memory> 36 37#include <lutok/state.hpp> 38 39namespace lutok { 40 41 42/// A RAII model for values on the Lua stack. 43/// 44/// At creation time, the object records the current depth of the Lua stack and, 45/// during destruction, restores the recorded depth by popping as many stack 46/// entries as required. As a corollary, the stack can only grow during the 47/// lifetime of a stack_cleaner object (or shrink, but cannot become shorter 48/// than the depth recorded at creation time). 49/// 50/// Use this class as follows: 51/// 52/// state s; 53/// { 54/// stack_cleaner cleaner1(s); 55/// s.push_integer(3); 56/// s.push_integer(5); 57/// ... do stuff here ... 58/// for (...) { 59/// stack_cleaner cleaner2(s); 60/// s.load_string("..."); 61/// s.pcall(0, 1, 0); 62/// ... do stuff here ... 63/// } 64/// // cleaner2 destroyed; the result of pcall is gone. 65/// } 66/// // cleaner1 destroyed; the integers 3 and 5 are gone. 67/// 68/// You must give a name to the instantiated objects even if they cannot be 69/// accessed later. Otherwise, the instance will be destroyed right away and 70/// will not have the desired effect. 71class stack_cleaner { 72 struct impl; 73 74 /// Pointer to the shared internal implementation. 75 std::auto_ptr< impl > _pimpl; 76 77 /// Disallow copies. 78 stack_cleaner(const stack_cleaner&); 79 80 /// Disallow assignment. 81 stack_cleaner& operator=(const stack_cleaner&); 82 83public: 84 stack_cleaner(state&); 85 ~stack_cleaner(void); 86 87 void forget(void); 88}; 89 90 91} // namespace lutok 92 93#endif // !defined(LUTOK_STACK_CLEANER_HPP) 94