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// file : build/utility -*- C++ -*-
// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
// license : MIT; see accompanying LICENSE file
#ifndef BUILD_UTILITY
#define BUILD_UTILITY
#include <tuple>
#include <string>
#include <utility>
#include <exception>
#include <unordered_set>
#include <build/path>
namespace build
{
// Empty string and path.
//
extern const std::string empty_string;
extern const path empty_path;
extern const dir_path empty_dir_path;
// Call a function if there is an exception.
//
// Means we are in the body of a destructor that is being called
// as part of the exception stack unwindining. Used to compensate
// for the deficiencies of uncaught_exception() until C++17
// uncaught_exceptions() becomes available.
//
// @@ MT: will have to be TLS.
//
extern bool exception_unwinding_dtor;
template <typename F, typename T>
struct exception_guard;
template <typename F, typename... A>
inline exception_guard<F, std::tuple<A&&...>>
make_exception_guard (F f, A&&... a)
{
return exception_guard<F, std::tuple<A&&...>> (
std::move (f), std::forward_as_tuple (a...));
}
template <typename F, typename... A>
struct exception_guard<F, std::tuple<A...>>
{
typedef std::tuple<A...> T;
exception_guard (F f, T a): f_ (std::move (f)), a_ (std::move (a)) {}
~exception_guard ()
{
if (std::uncaught_exception ())
{
exception_unwinding_dtor = true;
call (std::index_sequence_for<A...> ());
exception_unwinding_dtor = false;
}
}
private:
template <std::size_t... I>
void
call (std::index_sequence<I...>) {f_ (std::get<I> (a_)...);}
F f_;
T a_;
};
// Pools (@@ perhaps move into a separate header).
//
struct string_pool: std::unordered_set<std::string>
{
const std::string&
find (const char* s) {return *emplace (s).first;}
};
extern string_pool extension_pool;
}
#endif // BUILD_UTILITY
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