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Diffstat (limited to 'security/sandbox/chromium/base/tuple.h')
-rw-r--r-- | security/sandbox/chromium/base/tuple.h | 306 |
1 files changed, 306 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/tuple.h b/security/sandbox/chromium/base/tuple.h new file mode 100644 index 000000000..e5872cc4f --- /dev/null +++ b/security/sandbox/chromium/base/tuple.h @@ -0,0 +1,306 @@ +// Copyright (c) 2011 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +// A Tuple is a generic templatized container, similar in concept to std::pair +// and std::tuple. The convenient MakeTuple() function takes any number of +// arguments and will construct and return the appropriate Tuple object. The +// functions DispatchToMethod and DispatchToFunction take a function pointer or +// instance and method pointer, and unpack a tuple into arguments to the call. +// +// Tuple elements are copied by value, and stored in the tuple. See the unit +// tests for more details of how/when the values are copied. +// +// Example usage: +// // These two methods of creating a Tuple are identical. +// Tuple<int, const char*> tuple_a(1, "wee"); +// Tuple<int, const char*> tuple_b = MakeTuple(1, "wee"); +// +// void SomeFunc(int a, const char* b) { } +// DispatchToFunction(&SomeFunc, tuple_a); // SomeFunc(1, "wee") +// DispatchToFunction( +// &SomeFunc, MakeTuple(10, "foo")); // SomeFunc(10, "foo") +// +// struct { void SomeMeth(int a, int b, int c) { } } foo; +// DispatchToMethod(&foo, &Foo::SomeMeth, MakeTuple(1, 2, 3)); +// // foo->SomeMeth(1, 2, 3); + +#ifndef BASE_TUPLE_H_ +#define BASE_TUPLE_H_ + +#include <stddef.h> + +#include "base/bind_helpers.h" +#include "build/build_config.h" + +namespace base { + +// Index sequences +// +// Minimal clone of the similarly-named C++14 functionality. + +template <size_t...> +struct IndexSequence {}; + +template <size_t... Ns> +struct MakeIndexSequenceImpl; + +#if defined(_PREFAST_) && defined(OS_WIN) + +// Work around VC++ 2013 /analyze internal compiler error: +// https://connect.microsoft.com/VisualStudio/feedback/details/1053626 + +template <> struct MakeIndexSequenceImpl<0> { + using Type = IndexSequence<>; +}; +template <> struct MakeIndexSequenceImpl<1> { + using Type = IndexSequence<0>; +}; +template <> struct MakeIndexSequenceImpl<2> { + using Type = IndexSequence<0,1>; +}; +template <> struct MakeIndexSequenceImpl<3> { + using Type = IndexSequence<0,1,2>; +}; +template <> struct MakeIndexSequenceImpl<4> { + using Type = IndexSequence<0,1,2,3>; +}; +template <> struct MakeIndexSequenceImpl<5> { + using Type = IndexSequence<0,1,2,3,4>; +}; +template <> struct MakeIndexSequenceImpl<6> { + using Type = IndexSequence<0,1,2,3,4,5>; +}; +template <> struct MakeIndexSequenceImpl<7> { + using Type = IndexSequence<0,1,2,3,4,5,6>; +}; +template <> struct MakeIndexSequenceImpl<8> { + using Type = IndexSequence<0,1,2,3,4,5,6,7>; +}; +template <> struct MakeIndexSequenceImpl<9> { + using Type = IndexSequence<0,1,2,3,4,5,6,7,8>; +}; +template <> struct MakeIndexSequenceImpl<10> { + using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9>; +}; +template <> struct MakeIndexSequenceImpl<11> { + using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10>; +}; +template <> struct MakeIndexSequenceImpl<12> { + using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10,11>; +}; +template <> struct MakeIndexSequenceImpl<13> { + using Type = IndexSequence<0,1,2,3,4,5,6,7,8,9,10,11,12>; +}; + +#else // defined(WIN) && defined(_PREFAST_) + +template <size_t... Ns> +struct MakeIndexSequenceImpl<0, Ns...> { + using Type = IndexSequence<Ns...>; +}; + +template <size_t N, size_t... Ns> +struct MakeIndexSequenceImpl<N, Ns...> + : MakeIndexSequenceImpl<N - 1, N - 1, Ns...> {}; + +#endif // defined(WIN) && defined(_PREFAST_) + +template <size_t N> +using MakeIndexSequence = typename MakeIndexSequenceImpl<N>::Type; + +// Traits ---------------------------------------------------------------------- +// +// A simple traits class for tuple arguments. +// +// ValueType: the bare, nonref version of a type (same as the type for nonrefs). +// RefType: the ref version of a type (same as the type for refs). +// ParamType: what type to pass to functions (refs should not be constified). + +template <class P> +struct TupleTraits { + typedef P ValueType; + typedef P& RefType; + typedef const P& ParamType; +}; + +template <class P> +struct TupleTraits<P&> { + typedef P ValueType; + typedef P& RefType; + typedef P& ParamType; +}; + +// Tuple ----------------------------------------------------------------------- +// +// This set of classes is useful for bundling 0 or more heterogeneous data types +// into a single variable. The advantage of this is that it greatly simplifies +// function objects that need to take an arbitrary number of parameters; see +// RunnableMethod and IPC::MessageWithTuple. +// +// Tuple<> is supplied to act as a 'void' type. It can be used, for example, +// when dispatching to a function that accepts no arguments (see the +// Dispatchers below). +// Tuple<A> is rarely useful. One such use is when A is non-const ref that you +// want filled by the dispatchee, and the tuple is merely a container for that +// output (a "tier"). See MakeRefTuple and its usages. + +template <typename IxSeq, typename... Ts> +struct TupleBaseImpl; +template <typename... Ts> +using TupleBase = TupleBaseImpl<MakeIndexSequence<sizeof...(Ts)>, Ts...>; +template <size_t N, typename T> +struct TupleLeaf; + +template <typename... Ts> +struct Tuple final : TupleBase<Ts...> { + Tuple() : TupleBase<Ts...>() {} + explicit Tuple(typename TupleTraits<Ts>::ParamType... args) + : TupleBase<Ts...>(args...) {} +}; + +// Avoids ambiguity between Tuple's two constructors. +template <> +struct Tuple<> final {}; + +template <size_t... Ns, typename... Ts> +struct TupleBaseImpl<IndexSequence<Ns...>, Ts...> : TupleLeaf<Ns, Ts>... { + TupleBaseImpl() : TupleLeaf<Ns, Ts>()... {} + explicit TupleBaseImpl(typename TupleTraits<Ts>::ParamType... args) + : TupleLeaf<Ns, Ts>(args)... {} +}; + +template <size_t N, typename T> +struct TupleLeaf { + TupleLeaf() {} + explicit TupleLeaf(typename TupleTraits<T>::ParamType x) : x(x) {} + + T& get() { return x; } + const T& get() const { return x; } + + T x; +}; + +// Tuple getters -------------------------------------------------------------- +// +// Allows accessing an arbitrary tuple element by index. +// +// Example usage: +// base::Tuple<int, double> t2; +// base::get<0>(t2) = 42; +// base::get<1>(t2) = 3.14; + +template <size_t I, typename T> +T& get(TupleLeaf<I, T>& leaf) { + return leaf.get(); +} + +template <size_t I, typename T> +const T& get(const TupleLeaf<I, T>& leaf) { + return leaf.get(); +} + +// Tuple types ---------------------------------------------------------------- +// +// Allows for selection of ValueTuple/RefTuple/ParamTuple without needing the +// definitions of class types the tuple takes as parameters. + +template <typename T> +struct TupleTypes; + +template <typename... Ts> +struct TupleTypes<Tuple<Ts...>> { + using ValueTuple = Tuple<typename TupleTraits<Ts>::ValueType...>; + using RefTuple = Tuple<typename TupleTraits<Ts>::RefType...>; + using ParamTuple = Tuple<typename TupleTraits<Ts>::ParamType...>; +}; + +// Tuple creators ------------------------------------------------------------- +// +// Helper functions for constructing tuples while inferring the template +// argument types. + +template <typename... Ts> +inline Tuple<Ts...> MakeTuple(const Ts&... arg) { + return Tuple<Ts...>(arg...); +} + +// The following set of helpers make what Boost refers to as "Tiers" - a tuple +// of references. + +template <typename... Ts> +inline Tuple<Ts&...> MakeRefTuple(Ts&... arg) { + return Tuple<Ts&...>(arg...); +} + +// Dispatchers ---------------------------------------------------------------- +// +// Helper functions that call the given method on an object, with the unpacked +// tuple arguments. Notice that they all have the same number of arguments, +// so you need only write: +// DispatchToMethod(object, &Object::method, args); +// This is very useful for templated dispatchers, since they don't need to know +// what type |args| is. + +// Non-Static Dispatchers with no out params. + +template <typename ObjT, typename Method, typename... Ts, size_t... Ns> +inline void DispatchToMethodImpl(ObjT* obj, + Method method, + const Tuple<Ts...>& arg, + IndexSequence<Ns...>) { + (obj->*method)(base::internal::UnwrapTraits<Ts>::Unwrap(get<Ns>(arg))...); +} + +template <typename ObjT, typename Method, typename... Ts> +inline void DispatchToMethod(ObjT* obj, + Method method, + const Tuple<Ts...>& arg) { + DispatchToMethodImpl(obj, method, arg, MakeIndexSequence<sizeof...(Ts)>()); +} + +// Static Dispatchers with no out params. + +template <typename Function, typename... Ts, size_t... Ns> +inline void DispatchToFunctionImpl(Function function, + const Tuple<Ts...>& arg, + IndexSequence<Ns...>) { + (*function)(base::internal::UnwrapTraits<Ts>::Unwrap(get<Ns>(arg))...); +} + +template <typename Function, typename... Ts> +inline void DispatchToFunction(Function function, const Tuple<Ts...>& arg) { + DispatchToFunctionImpl(function, arg, MakeIndexSequence<sizeof...(Ts)>()); +} + +// Dispatchers with out parameters. + +template <typename ObjT, + typename Method, + typename... InTs, + typename... OutTs, + size_t... InNs, + size_t... OutNs> +inline void DispatchToMethodImpl(ObjT* obj, + Method method, + const Tuple<InTs...>& in, + Tuple<OutTs...>* out, + IndexSequence<InNs...>, + IndexSequence<OutNs...>) { + (obj->*method)(base::internal::UnwrapTraits<InTs>::Unwrap(get<InNs>(in))..., + &get<OutNs>(*out)...); +} + +template <typename ObjT, typename Method, typename... InTs, typename... OutTs> +inline void DispatchToMethod(ObjT* obj, + Method method, + const Tuple<InTs...>& in, + Tuple<OutTs...>* out) { + DispatchToMethodImpl(obj, method, in, out, + MakeIndexSequence<sizeof...(InTs)>(), + MakeIndexSequence<sizeof...(OutTs)>()); +} + +} // namespace base + +#endif // BASE_TUPLE_H_ |