summaryrefslogtreecommitdiffstats
path: root/media/mtransport/runnable_utils.h
blob: 0d7b1ce6f9dc05869685a324ec7e530841b4c59f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
/* -*- 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)
{
  nsCOMPtr<nsIRunnable> runnable_ref(runnable);
  if (thread) {
    bool on;
    nsresult rv;
    rv = thread->IsOnCurrentThread(&on);

    // If the target thread has already shut down, we don't want to assert.
    if (rv != NS_ERROR_NOT_INITIALIZED) {
      MOZ_ASSERT(NS_SUCCEEDED(rv));
    }

    if (NS_WARN_IF(NS_FAILED(rv))) {
      // we're going to destroy the runnable on this thread!
      return rv;
    }
    if (!on) {
      return thread->Dispatch(runnable_ref.forget(), flags);
    }
  }
  return runnable_ref->Run();
}

template<RunnableResult result>
class runnable_args_base : public Runnable {
 public:
  NS_IMETHOD Run() = 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|.
  explicit runnable_args_func(FunType f, Args&&... args)
    : mFunc(f), mArgs(Forward<Args>(args)...)
  {}

  NS_IMETHOD Run() {
    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, Args...>*
WrapRunnableNM(FunType f, Args... args)
{
  return new runnable_args_func<FunType, Args...>(f, Move(args)...);
}

template<typename Ret, typename FunType, typename... Args>
class runnable_args_func_ret : public detail::runnable_args_base<detail::ReturnsResult>
{
public:
  runnable_args_func_ret(Ret* ret, FunType f, Args&&... args)
    : mReturn(ret), mFunc(f), mArgs(Forward<Args>(args)...)
  {}

  NS_IMETHOD Run() {
    *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, Args...>*
WrapRunnableNMRet(R* ret, FunType f, Args... args)
{
  return new runnable_args_func_ret<R, FunType, Args...>(ret, f, Move(args)...);
}

template<typename Class, typename M, typename... Args>
class runnable_args_memfn : public detail::runnable_args_base<detail::NoResult>
{
public:
  runnable_args_memfn(Class obj, M method, Args&&... args)
    : mObj(obj), mMethod(method), mArgs(Forward<Args>(args)...)
  {}

  NS_IMETHOD Run() {
    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, Args...>*
WrapRunnable(Class obj, M method, Args... args)
{
  return new runnable_args_memfn<Class, M, Args...>(obj, method, Move(args)...);
}

template<typename Ret, typename Class, typename M, typename... Args>
class runnable_args_memfn_ret : public detail::runnable_args_base<detail::ReturnsResult>
{
public:
  runnable_args_memfn_ret(Ret* ret, Class obj, M method, Args... args)
    : mReturn(ret), mObj(obj), mMethod(method), mArgs(Forward<Args>(args)...)
  {}

  NS_IMETHOD Run() {
    *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, Args...>*
WrapRunnableRet(R* ret, Class obj, M method, Args... args)
{
  return new runnable_args_memfn_ret<R, Class, M, Args...>(ret, obj, method, Move(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() {
    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