summaryrefslogtreecommitdiffstats
path: root/base/bind_internal.h.pump
blob: 7fd63d89d0c256fe5fcab01c84653304d0f9db49 (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
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
$$ This is a pump file for generating file templates.  Pump is a python
$$ script that is part of the Google Test suite of utilities.  Description
$$ can be found here:
$$
$$ http://code.google.com/p/googletest/wiki/PumpManual
$$

$$ See comment for MAX_ARITY in base/bind.h.pump.
$var MAX_ARITY = 7
$range ARITY 0..MAX_ARITY

// 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.

#ifndef BASE_BIND_INTERNAL_H_
#define BASE_BIND_INTERNAL_H_
#pragma once

#include "base/bind_helpers.h"
#include "base/callback_internal.h"
#include "base/memory/raw_scoped_refptr_mismatch_checker.h"
#include "base/memory/weak_ptr.h"
#include "base/template_util.h"
#include "build/build_config.h"

#if defined(OS_WIN)
#include "base/bind_internal_win.h"
#endif

namespace base {
namespace internal {

// CONCEPTS:
//  Runnable -- A type (really a type class) that has a single Run() method
//              and a RunType typedef that corresponds to the type of Run().
//              A Runnable can declare that it should treated like a method
//              call by including a typedef named IsMethod.  The value of
//              this typedef is NOT inspected, only the existence.  When a
//              Runnable declares itself a method, Bind() will enforce special
//              refcounting + WeakPtr handling semantics for the first
//              parameter which is expected to be an object.
//  Functor -- A copyable type representing something that should be called.
//             All function pointers, Callback<>, and Runnables are functors
//             even if the invocation syntax differs.
//  RunType -- A function type (as opposed to function _pointer_ type) for
//             a Run() function.  Usually just a convenience typedef.
//  (Bound)ArgsType -- A function type that is being (ab)used to store the
//                     types of set of arguments.  The "return" type is always
//                     void here.  We use this hack so that we do not need
//                     a new type name for each arity of type. (eg.,
//                     BindState1, BindState2).  This makes forward
//                     declarations and friending much much easier.
//
// Types:
//  RunnableAdapter<> -- Wraps the various "function" pointer types into an
//                       object that adheres to the Runnable interface.
//                       There are |3*ARITY| RunnableAdapter types.
//  FunctionTraits<> -- Type traits that unwrap a function signature into a
//                      a set of easier to use typedefs.  Used mainly for
//                      compile time asserts.
//                      There are |ARITY| FunctionTraits types.
//  ForceVoidReturn<> -- Helper class for translating function signatures to
//                       equivalent forms with a "void" return type.
//                    There are |ARITY| ForceVoidReturn types.
//  FunctorTraits<> -- Type traits used determine the correct RunType and
//                     RunnableType for a Functor.  This is where function
//                     signature adapters are applied.
//                    There are |ARITY| ForceVoidReturn types.
//  MakeRunnable<> -- Takes a Functor and returns an object in the Runnable
//                    type class that represents the underlying Functor.
//                    There are |O(1)| MakeRunnable types.
//  InvokeHelper<> -- Take a Runnable + arguments and actully invokes it.
//                    Handle the differing syntaxes needed for WeakPtr<> support,
//                    and for ignoring return values.  This is separate from
//                    Invoker to avoid creating multiple version of Invoker<>
//                    which grows at O(n^2) with the arity.
//                    There are |k*ARITY| InvokeHelper types.
//  Invoker<> -- Unwraps the curried parameters and executes the Runnable.
//               There are |(ARITY^2 + ARITY)/2| Invoketypes.
//  BindState<> -- Stores the curried parameters, and is the main entry point
//                 into the Bind() system, doing most of the type resolution.
//                 There are ARITY BindState types.

// RunnableAdapter<>
//
// The RunnableAdapter<> templates provide a uniform interface for invoking
// a function pointer, method pointer, or const method pointer. The adapter
// exposes a Run() method with an appropriate signature. Using this wrapper
// allows for writing code that supports all three pointer types without
// undue repetition.  Without it, a lot of code would need to be repeated 3
// times.
//
// For method pointers and const method pointers the first argument to Run()
// is considered to be the received of the method.  This is similar to STL's
// mem_fun().
//
// This class also exposes a RunType typedef that is the function type of the
// Run() function.
//
// If and only if the wrapper contains a method or const method pointer, an
// IsMethod typedef is exposed.  The existence of this typedef (NOT the value)
// marks that the wrapper should be considered a method wrapper.

template <typename Functor>
class RunnableAdapter;

$for ARITY [[
$range ARG 1..ARITY

// Function: Arity $(ARITY).
template <typename R[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename A$(ARG)]]>
class RunnableAdapter<R(*)($for ARG , [[A$(ARG)]])> {
 public:
  typedef R (RunType)($for ARG , [[A$(ARG)]]);

  explicit RunnableAdapter(R(*function)($for ARG , [[A$(ARG)]]))
      : function_(function) {
  }

  R Run($for ARG , [[typename CallbackParamTraits<A$(ARG)>::ForwardType a$(ARG)]]) {
    return function_($for ARG , [[CallbackForward(a$(ARG))]]);
  }

 private:
  R (*function_)($for ARG , [[A$(ARG)]]);
};

// Method: Arity $(ARITY).
template <typename R, typename T[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename A$(ARG)]]>
class RunnableAdapter<R(T::*)($for ARG , [[A$(ARG)]])> {
 public:
  typedef R (RunType)(T*[[]]
$if ARITY > 0[[, ]] $for ARG , [[A$(ARG)]]);
  typedef true_type IsMethod;

  explicit RunnableAdapter(R(T::*method)($for ARG , [[A$(ARG)]]))
      : method_(method) {
  }

  R Run(T* object[[]]
$if ARITY > 0[[, ]]  $for ARG, [[typename CallbackParamTraits<A$(ARG)>::ForwardType a$(ARG)]]) {
    return (object->*method_)($for ARG , [[CallbackForward(a$(ARG))]]);
  }

 private:
  R (T::*method_)($for ARG , [[A$(ARG)]]);
};

// Const Method: Arity $(ARITY).
template <typename R, typename T[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename A$(ARG)]]>
class RunnableAdapter<R(T::*)($for ARG , [[A$(ARG)]]) const> {
 public:
  typedef R (RunType)(const T*[[]]
$if ARITY > 0[[, ]] $for ARG , [[A$(ARG)]]);
  typedef true_type IsMethod;

  explicit RunnableAdapter(R(T::*method)($for ARG , [[A$(ARG)]]) const)
      : method_(method) {
  }

  R Run(const T* object[[]]
$if ARITY > 0[[, ]]  $for ARG, [[typename CallbackParamTraits<A$(ARG)>::ForwardType a$(ARG)]]) {
    return (object->*method_)($for ARG , [[CallbackForward(a$(ARG))]]);
  }

 private:
  R (T::*method_)($for ARG , [[A$(ARG)]]) const;
};

]]  $$ for ARITY


// FunctionTraits<>
//
// Breaks a function signature apart into typedefs for easier introspection.
template <typename Sig>
struct FunctionTraits;

$for ARITY [[
$range ARG 1..ARITY

template <typename R[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename A$(ARG)]]>
struct FunctionTraits<R($for ARG , [[A$(ARG)]])> {
  typedef R ReturnType;
$for ARG [[

  typedef A$(ARG) A$(ARG)Type;
]]

};

]]


// ForceVoidReturn<>
//
// Set of templates that support forcing the function return type to void.
template <typename Sig>
struct ForceVoidReturn;

$for ARITY [[
$range ARG 1..ARITY

template <typename R[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename A$(ARG)]]>
struct ForceVoidReturn<R($for ARG , [[A$(ARG)]])> {
  typedef void(RunType)($for ARG , [[A$(ARG)]]);
};

]]  $$ for ARITY


// FunctorTraits<>
//
// See description at top of file.
template <typename T>
struct FunctorTraits {
  typedef RunnableAdapter<T> RunnableType;
  typedef typename RunnableType::RunType RunType;
};

template <typename T>
struct FunctorTraits<IgnoreResultHelper<T> > {
  typedef typename FunctorTraits<T>::RunnableType RunnableType;
  typedef typename ForceVoidReturn<
      typename RunnableType::RunType>::RunType RunType;
};

template <typename T>
struct FunctorTraits<Callback<T> > {
  typedef Callback<T> RunnableType;
  typedef typename Callback<T>::RunType RunType;
};


// MakeRunnable<>
//
// Converts a passed in functor to a RunnableType using type inference.

template <typename T>
typename FunctorTraits<T>::RunnableType MakeRunnable(const T& t) {
  return RunnableAdapter<T>(t);
}

template <typename T>
typename FunctorTraits<T>::RunnableType
MakeRunnable(const IgnoreResultHelper<T>& t) {
  return MakeRunnable(t.functor_);
}

template <typename T>
const typename FunctorTraits<Callback<T> >::RunnableType&
MakeRunnable(const Callback<T>& t) {
  return t;
}


// InvokeHelper<>
//
// There are 3 logical InvokeHelper<> specializations: normal, void-return,
// WeakCalls.
//
// The normal type just calls the underlying runnable.
//
// We need a InvokeHelper to handle void return types in order to support
// IgnoreResult().  Normally, if the Runnable's RunType had a void return,
// the template system would just accept "return functor.Run()" ignoring
// the fact that a void function is being used with return. This piece of
// sugar breaks though when the Runnable's RunType is not void.  Thus, we
// need a partial specialization to change the syntax to drop the "return"
// from the invocation call.
//
// WeakCalls similarly need special syntax that is applied to the first
// argument to check if they should no-op themselves.
template <bool IsWeakCall, typename ReturnType, typename Runnable,
          typename ArgsType>
struct InvokeHelper;

$for ARITY [[
$range ARG 1..ARITY

template <typename ReturnType, typename Runnable[[]]
$if ARITY > 0 [[,]] $for ARG , [[typename A$(ARG)]]>
struct InvokeHelper<false, ReturnType, Runnable,
    void($for ARG , [[A$(ARG)]])>  {
  static ReturnType MakeItSo(Runnable runnable[[]]
$if ARITY > 0[[, ]] $for ARG , [[A$(ARG) a$(ARG)]]) {
    return runnable.Run($for ARG , [[CallbackForward(a$(ARG))]]);
  }
};

template <typename Runnable[[]]
$if ARITY > 0 [[,]] $for ARG , [[typename A$(ARG)]]>
struct InvokeHelper<false, void, Runnable,
    void($for ARG , [[A$(ARG)]])>  {
  static void MakeItSo(Runnable runnable[[]]
$if ARITY > 0[[, ]] $for ARG , [[A$(ARG) a$(ARG)]]) {
    runnable.Run($for ARG , [[CallbackForward(a$(ARG))]]);
  }
};

$if ARITY > 0 [[

template <typename Runnable[[]], $for ARG , [[typename A$(ARG)]]>
struct InvokeHelper<true, void, Runnable,
    void($for ARG , [[A$(ARG)]])>  {
  static void MakeItSo(Runnable runnable[[]]
$if ARITY > 0[[, ]] $for ARG , [[A$(ARG) a$(ARG)]]) {
    if (!a1.get()) {
      return;
    }

    runnable.Run($for ARG , [[CallbackForward(a$(ARG))]]);
  }
};

]]

]] $$ for ARITY

#if !defined(_MSC_VER)

template <typename ReturnType, typename Runnable, typename ArgsType>
struct InvokeHelper<true, ReturnType, Runnable, ArgsType> {
  // WeakCalls are only supported for functions with a void return type.
  // Otherwise, the function result would be undefined if the the WeakPtr<>
  // is invalidated.
  COMPILE_ASSERT(is_void<ReturnType>::value,
                 weak_ptrs_can_only_bind_to_methods_without_return_values);
};

#endif

// Invoker<>
//
// See description at the top of the file.
template <int NumBound, typename Storage, typename RunType>
struct Invoker;

$for ARITY [[

$$ Number of bound arguments.
$range BOUND 0..ARITY
$for BOUND [[

$var UNBOUND = ARITY - BOUND
$range ARG 1..ARITY
$range BOUND_ARG 1..BOUND
$range UNBOUND_ARG (ARITY - UNBOUND + 1)..ARITY

// Arity $(ARITY) -> $(UNBOUND).
template <typename StorageType, typename R[[]]
$if ARITY > 0 [[,]][[]]
$for ARG , [[typename X$(ARG)]]>
struct Invoker<$(BOUND), StorageType, R($for ARG , [[X$(ARG)]])> {
  typedef R(RunType)(BindStateBase*[[]]
$if UNBOUND != 0 [[, ]]
$for UNBOUND_ARG , [[typename CallbackParamTraits<X$(UNBOUND_ARG)>::ForwardType]]);

  typedef R(UnboundRunType)($for UNBOUND_ARG , [[X$(UNBOUND_ARG)]]);

  static R Run(BindStateBase* base[[]]
$if UNBOUND != 0 [[, ]][[]]
$for UNBOUND_ARG , [[
typename CallbackParamTraits<X$(UNBOUND_ARG)>::ForwardType x$(UNBOUND_ARG)
]][[]]
) {
    StorageType* storage = static_cast<StorageType*>(base);

    // Local references to make debugger stepping easier. If in a debugger,
    // you really want to warp ahead and step through the
    // InvokeHelper<>::MakeItSo() call below.
$for BOUND_ARG
[[

    typedef typename StorageType::Bound$(BOUND_ARG)UnwrapTraits Bound$(BOUND_ARG)UnwrapTraits;
]]


$for BOUND_ARG
[[

    typename Bound$(BOUND_ARG)UnwrapTraits::ForwardType x$(BOUND_ARG) =
        Bound$(BOUND_ARG)UnwrapTraits::Unwrap(storage->p$(BOUND_ARG)_);
]]

    return InvokeHelper<StorageType::IsWeakCall::value, R,
           typename StorageType::RunnableType,
           void(
$for BOUND_ARG , [[
typename Bound$(BOUND_ARG)UnwrapTraits::ForwardType
]]

$if UNBOUND > 0 [[$if BOUND > 0 [[, ]]]][[]]

$for UNBOUND_ARG , [[
typename CallbackParamTraits<X$(UNBOUND_ARG)>::ForwardType x$(UNBOUND_ARG)
]]
)>
               ::MakeItSo(storage->runnable_
$if ARITY > 0[[, ]] $for ARG , [[CallbackForward(x$(ARG))]]);
  }
};

]] $$ for BOUND
]] $$ for ARITY


// BindState<>
//
// This stores all the state passed into Bind() and is also where most
// of the template resolution magic occurs.
//
// Runnable is the functor we are binding arguments to.
// RunType is type of the Run() function that the Invoker<> should use.
// Normally, this is the same as the RunType of the Runnable, but it can
// be different if an adapter like IgnoreResult() has been used.
//
// BoundArgsType contains the storage type for all the bound arguments by
// (ab)using a function type.
template <typename Runnable, typename RunType, typename BoundArgsType>
struct BindState;

$for ARITY [[
$range ARG 1..ARITY

template <typename Runnable, typename RunType[[]]
$if ARITY > 0[[, ]] $for ARG , [[typename P$(ARG)]]>
struct BindState<Runnable, RunType, void($for ARG , [[P$(ARG)]])> : public BindStateBase {
  typedef Runnable RunnableType;

$if ARITY > 0 [[
  typedef IsWeakMethod<HasIsMethodTag<Runnable>::value, P1> IsWeakCall;
]] $else [[
  typedef false_type IsWeakCall;
]]

  typedef Invoker<$(ARITY), BindState, RunType> InvokerType;
  typedef typename InvokerType::UnboundRunType UnboundRunType;

$if ARITY > 0 [[

  // Convenience typedefs for bound argument types.

$for ARG [[
  typedef UnwrapTraits<P$(ARG)> Bound$(ARG)UnwrapTraits;

]]  $$ for ARG


]]  $$ if ARITY > 0

$$ The extra [[ ]] is needed to massage spacing. Silly pump.py.
[[  ]]$if ARITY == 0 [[explicit ]]BindState(const Runnable& runnable
$if ARITY > 0 [[, ]] $for ARG , [[const P$(ARG)& p$(ARG)]])
      : runnable_(runnable)[[]]
$if ARITY == 0 [[
 {

]] $else [[
, $for ARG , [[

        p$(ARG)_(p$(ARG))
]] {
    MaybeRefcount<HasIsMethodTag<Runnable>::value, P1>::AddRef(p1_);

]]
  }

  virtual ~BindState() {
$if ARITY > 0 [[
    MaybeRefcount<HasIsMethodTag<Runnable>::value, P1>::Release(p1_);
]]
  }

  RunnableType runnable_;

$for ARG [[
  P$(ARG) p$(ARG)_;

]]
};

]] $$ for ARITY

}  // namespace internal
}  // namespace base

#endif  // BASE_BIND_INTERNAL_H_