gecko-dev/media/mtransport/runnable_utils.h

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/. */
// Original author: ekr@rtfm.com
#ifndef runnable_utils_h__
#define runnable_utils_h__
#include "nsThreadUtils.h"
#include "mozilla/IndexSequence.h"
#include "mozilla/Move.h"
#include "mozilla/RefPtr.h"
#include "mozilla/Tuple.h"
// Abstract base class for all of our templates
namespace mozilla {
namespace detail {
enum RunnableResult {
NoResult,
ReturnsResult
};
static inline nsresult
RunOnThreadInternal(nsIEventTarget *thread, nsIRunnable *runnable, uint32_t flags)
{
return thread->Dispatch(runnable, flags);
}
template<RunnableResult result>
class runnable_args_base : public Runnable {
public:
runnable_args_base() : Runnable("media-runnable_args_base") {}
NS_IMETHOD Run() override = 0;
};
template<typename R>
struct RunnableFunctionCallHelper
{
template<typename FunType, typename... Args, size_t... Indices>
static R apply(FunType func, Tuple<Args...>& args, IndexSequence<Indices...>)
{
return func(Get<Indices>(args)...);
}
};
// A void specialization is needed in the case where the template instantiator
// knows we don't want to return a value, but we don't know whether the called
// function returns void or something else.
template<>
struct RunnableFunctionCallHelper<void>
{
template<typename FunType, typename... Args, size_t... Indices>
static void apply(FunType func, Tuple<Args...>& args, IndexSequence<Indices...>)
{
func(Get<Indices>(args)...);
}
};
template<typename R>
struct RunnableMethodCallHelper
{
template<typename Class, typename M, typename... Args, size_t... Indices>
static R apply(Class obj, M method, Tuple<Args...>& args, IndexSequence<Indices...>)
{
return ((*obj).*method)(Get<Indices>(args)...);
}
};
// A void specialization is needed in the case where the template instantiator
// knows we don't want to return a value, but we don't know whether the called
// method returns void or something else.
template<>
struct RunnableMethodCallHelper<void>
{
template<typename Class, typename M, typename... Args, size_t... Indices>
static void apply(Class obj, M method, Tuple<Args...>& args, IndexSequence<Indices...>)
{
((*obj).*method)(Get<Indices>(args)...);
}
};
}
template<typename FunType, typename... Args>
class runnable_args_func : public detail::runnable_args_base<detail::NoResult>
{
public:
// |explicit| to pacify static analysis when there are no |args|.
template<typename... Arguments>
explicit runnable_args_func(FunType f, Arguments&&... args)
: mFunc(f), mArgs(Forward<Arguments>(args)...)
{}
NS_IMETHOD Run() override {
detail::RunnableFunctionCallHelper<void>::apply(mFunc, mArgs, typename IndexSequenceFor<Args...>::Type());
return NS_OK;
}
private:
FunType mFunc;
Tuple<Args...> mArgs;
};
template<typename FunType, typename... Args>
runnable_args_func<FunType, typename mozilla::Decay<Args>::Type...>*
WrapRunnableNM(FunType f, Args&&... args)
{
return new runnable_args_func<FunType, typename mozilla::Decay<Args>::Type...>(f, Forward<Args>(args)...);
}
template<typename Ret, typename FunType, typename... Args>
class runnable_args_func_ret : public detail::runnable_args_base<detail::ReturnsResult>
{
public:
template<typename... Arguments>
runnable_args_func_ret(Ret* ret, FunType f, Arguments&&... args)
: mReturn(ret), mFunc(f), mArgs(Forward<Arguments>(args)...)
{}
NS_IMETHOD Run() override {
*mReturn = detail::RunnableFunctionCallHelper<Ret>::apply(mFunc, mArgs, typename IndexSequenceFor<Args...>::Type());
return NS_OK;
}
private:
Ret* mReturn;
FunType mFunc;
Tuple<Args...> mArgs;
};
template<typename R, typename FunType, typename... Args>
runnable_args_func_ret<R, FunType, typename mozilla::Decay<Args>::Type...>*
WrapRunnableNMRet(R* ret, FunType f, Args&&... args)
{
return new runnable_args_func_ret<R, FunType, typename mozilla::Decay<Args>::Type...>(ret, f, Forward<Args>(args)...);
}
template<typename Class, typename M, typename... Args>
class runnable_args_memfn : public detail::runnable_args_base<detail::NoResult>
{
public:
template<typename... Arguments>
runnable_args_memfn(Class obj, M method, Arguments&&... args)
: mObj(obj), mMethod(method), mArgs(Forward<Arguments>(args)...)
{}
NS_IMETHOD Run() override {
detail::RunnableMethodCallHelper<void>::apply(mObj, mMethod, mArgs, typename IndexSequenceFor<Args...>::Type());
return NS_OK;
}
private:
Class mObj;
M mMethod;
Tuple<Args...> mArgs;
};
template<typename Class, typename M, typename... Args>
runnable_args_memfn<Class, M, typename mozilla::Decay<Args>::Type...>*
WrapRunnable(Class obj, M method, Args&&... args)
{
return new runnable_args_memfn<Class, M, typename mozilla::Decay<Args>::Type...>(obj, method, Forward<Args>(args)...);
}
template<typename Ret, typename Class, typename M, typename... Args>
class runnable_args_memfn_ret : public detail::runnable_args_base<detail::ReturnsResult>
{
public:
template<typename... Arguments>
runnable_args_memfn_ret(Ret* ret, Class obj, M method, Arguments... args)
: mReturn(ret), mObj(obj), mMethod(method), mArgs(Forward<Arguments>(args)...)
{}
NS_IMETHOD Run() override {
*mReturn = detail::RunnableMethodCallHelper<Ret>::apply(mObj, mMethod, mArgs, typename IndexSequenceFor<Args...>::Type());
return NS_OK;
}
private:
Ret* mReturn;
Class mObj;
M mMethod;
Tuple<Args...> mArgs;
};
template<typename R, typename Class, typename M, typename... Args>
runnable_args_memfn_ret<R, Class, M, typename mozilla::Decay<Args>::Type...>*
WrapRunnableRet(R* ret, Class obj, M method, Args&&... args)
{
return new runnable_args_memfn_ret<R, Class, M, typename mozilla::Decay<Args>::Type...>(ret, obj, method, Forward<Args>(args)...);
}
static inline nsresult RUN_ON_THREAD(nsIEventTarget *thread, detail::runnable_args_base<detail::NoResult> *runnable, uint32_t flags) {
return detail::RunOnThreadInternal(thread, static_cast<nsIRunnable *>(runnable), flags);
}
static inline nsresult
RUN_ON_THREAD(nsIEventTarget *thread, detail::runnable_args_base<detail::ReturnsResult> *runnable)
{
return detail::RunOnThreadInternal(thread, static_cast<nsIRunnable *>(runnable), NS_DISPATCH_SYNC);
}
#ifdef DEBUG
#define ASSERT_ON_THREAD(t) do { \
if (t) { \
bool on; \
nsresult rv; \
rv = t->IsOnCurrentThread(&on); \
MOZ_ASSERT(NS_SUCCEEDED(rv)); \
MOZ_ASSERT(on); \
} \
} while(0)
#else
#define ASSERT_ON_THREAD(t)
#endif
template <class T>
class DispatchedRelease : public detail::runnable_args_base<detail::NoResult> {
public:
explicit DispatchedRelease(already_AddRefed<T>& ref) : ref_(ref) {}
NS_IMETHOD Run() override {
ref_ = nullptr;
return NS_OK;
}
private:
RefPtr<T> ref_;
};
template <typename T>
DispatchedRelease<T>* WrapRelease(already_AddRefed<T>&& ref)
{
return new DispatchedRelease<T>(ref);
}
} /* namespace mozilla */
#endif