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
|
$$ This is a pump file for generating file templates. Pump is a python
$$ script that is part of the Google Test suite of utilities. Description
$$ can be found here:
$$
$$ http://code.google.com/p/googletest/wiki/PumpManual
$$
$var MAX_ARITY = 6
// 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/template_util.h"
namespace base {
namespace internal {
// The method by which a function is invoked is determined by 3 different
// dimensions:
//
// 1) The type of function (normal, method, const-method)
// 2) The arity of the function
// 3) The number of bound parameters.
//
// The FunctionTraitsN classes unwrap the function signature type to
// specialize based on the first two dimensions. The N in FunctionTraitsN
// specifies the 3rd dimension. We could have specified the unbound parameters
// via template parameters, but this method looked cleaner.
//
// The FunctionTraitsN contains a static DoInvoke() function that is the key to
// implementing type erasure in the Callback() classes. DoInvoke() is a static
// function with a fixed signature that is independent of StorageType; its
// first argument is a pointer to the non-templated common baseclass of
// StorageType. This lets us store pointer to DoInvoke() in a function pointer
// that has knowledge of the specific StorageType, and thus no knowledge of the
// bound function and bound parameter types.
//
// As long as we ensure that DoInvoke() is only used with pointers there were
// upcasted from the correct StorageType, we can be sure that execution is
// safe.
$range BOUND 0..MAX_ARITY
$for BOUND [[
template <typename StorageType, typename Sig>
struct FunctionTraits$(BOUND);
$range ARITY 0..MAX_ARITY
$for ARITY [[
$var UNBOUND = ARITY - BOUND
$if UNBOUND >= 0 [[
$$ Variables for function traits generation.
$range ARG 1..ARITY
$range BOUND_ARG 1..BOUND
$range UNBOUND_ARG (ARITY - UNBOUND + 1)..ARITY
$$ Variables for method traits generation. We are always short one arity since
$$ the first bound parameter is the object.
$var M_ARITY = ARITY - 1
$range M_ARG 1..M_ARITY
$range M_BOUND_ARG 2..BOUND
$range M_UNBOUND_ARG (M_ARITY - UNBOUND + 1)..M_ARITY
// Function: Arity $(ARITY) -> $(UNBOUND).
template <typename StorageType, typename R[[]]
$if ARITY > 0 [[,]][[]]
$for ARG , [[typename X$(ARG)]]>
struct FunctionTraits$(BOUND)<StorageType, R(*)($for ARG , [[X$(ARG)]])> {
$if ARITY > 0 [[
COMPILE_ASSERT(
!($for ARG || [[ is_non_const_reference<X$(ARG)>::value ]]),
do_not_bind_functions_with_nonconst_ref);
]]
typedef base::false_type IsMethod;
static R DoInvoke(InvokerStorageBase* base[[]]
$if UNBOUND != 0 [[, ]][[]]
$for UNBOUND_ARG , [[const X$(UNBOUND_ARG)& x$(UNBOUND_ARG)]]) {
StorageType* invoker = static_cast<StorageType*>(base);
return invoker->f_($for BOUND_ARG , [[Unwrap(invoker->p$(BOUND_ARG)_)]][[]]
$$ Add comma if there are both boudn and unbound args.
$if UNBOUND > 0 [[$if BOUND > 0 [[, ]]]][[]]
$for UNBOUND_ARG , [[x$(UNBOUND_ARG)]]);
}
};
$if BOUND > 0 [[
// Method: Arity $(M_ARITY) -> $(UNBOUND).
template <typename StorageType, typename R, typename T[[]]
$if M_ARITY > 0[[, ]] $for M_ARG , [[typename X$(M_ARG)]]>
struct FunctionTraits$(BOUND)<StorageType, R(T::*)($for M_ARG , [[X$(M_ARG)]])> {
$if M_ARITY > 0 [[
COMPILE_ASSERT(
!($for M_ARG || [[ is_non_const_reference<X$(M_ARG)>::value ]]),
do_not_bind_functions_with_nonconst_ref);
]]
typedef base::true_type IsMethod;
static R DoInvoke(InvokerStorageBase* base[[]]
$if UNBOUND > 0 [[, ]][[]]
$for M_UNBOUND_ARG , [[const X$(M_UNBOUND_ARG)& x$(M_UNBOUND_ARG)]]) {
StorageType* invoker = static_cast<StorageType*>(base);
return (Unwrap(invoker->p1_)->*invoker->f_)([[]]
$for M_BOUND_ARG , [[Unwrap(invoker->p$(M_BOUND_ARG)_)]][[]]
$if UNBOUND > 0 [[$if BOUND > 1 [[, ]]]][[]]
$for M_UNBOUND_ARG , [[x$(M_UNBOUND_ARG)]]);
}
};
// Const Method: Arity $(M_ARITY) -> $(UNBOUND).
template <typename StorageType, typename R, typename T[[]]
$if M_ARITY > 0[[, ]] $for M_ARG , [[typename X$(M_ARG)]]>
struct FunctionTraits$(BOUND)<StorageType, R(T::*)($for M_ARG , [[X$(M_ARG)]]) const> {
$if M_ARITY > 0 [[
COMPILE_ASSERT(
!($for M_ARG || [[is_non_const_reference<X$(M_ARG)>::value ]]),
do_not_bind_functions_with_nonconst_ref);
]]
typedef base::true_type IsMethod;
static R DoInvoke(InvokerStorageBase* base[[]]
$if UNBOUND > 0 [[, ]]
[[]] $for M_UNBOUND_ARG , [[const X$(M_UNBOUND_ARG)& x$(M_UNBOUND_ARG)]]) {
StorageType* invoker = static_cast<StorageType*>(base);
return (Unwrap(invoker->p1_)->*invoker->f_)([[]]
$for M_BOUND_ARG , [[Unwrap(invoker->p$(M_BOUND_ARG)_)]][[]]
$if UNBOUND > 0 [[$if BOUND > 1 [[, ]]]][[]]
$for M_UNBOUND_ARG , [[x$(M_UNBOUND_ARG)]]);
}
};
]] $$ if BOUND
]] $$ if UNBOUND
]] $$ for ARITY
]] $$ for BOUND
// These are the actual storage classes for the invokers.
//
// Though these types are "classes", they are being used as structs with
// all member variable public. We cannot make it a struct because it inherits
// from a class which causes a compiler warning. We cannot add a "Run()" method
// that forwards the unbound arguments because that would require we unwrap the
// Sig type like in FunctionTraitsN above to know the return type, and the arity
// of Run().
//
// An alternate solution would be to merge FunctionTraitsN and InvokerStorageN,
// but the generated code seemed harder to read.
$for BOUND [[
$range BOUND_ARG 1..BOUND
template <typename Sig[[]]
$if BOUND > 0 [[, ]]
$for BOUND_ARG , [[typename P$(BOUND_ARG)]]>
class InvokerStorage$(BOUND) : public InvokerStorageBase {
public:
typedef InvokerStorage$(BOUND) StorageType;
typedef FunctionTraits$(BOUND)<StorageType, Sig> FunctionTraits;
typedef typename FunctionTraits::IsMethod IsMethod;
$for BOUND_ARG [[
$if BOUND_ARG == 1 [[
// For methods, we need to be careful for parameter 1. We skip the
// scoped_refptr check because the binder itself takes care of this. We also
// disallow binding of an array as the method's target object.
COMPILE_ASSERT(IsMethod::value ||
!internal::UnsafeBindtoRefCountedArg<P$(BOUND_ARG)>::value,
p$(BOUND_ARG)_is_refcounted_type_and_needs_scoped_refptr);
COMPILE_ASSERT(!IsMethod::value || !is_array<P$(BOUND_ARG)>::value,
first_bound_argument_to_method_cannot_be_array);
]] $else [[
COMPILE_ASSERT(!internal::UnsafeBindtoRefCountedArg<P$(BOUND_ARG)>::value,
p$(BOUND_ARG)_is_refcounted_type_and_needs_scoped_refptr);
]] $$ $if BOUND_ARG
]] $$ $for BOUND_ARG
InvokerStorage$(BOUND)(Sig f
$if BOUND > 0 [[, ]]
$for BOUND_ARG , [[const P$(BOUND_ARG)& p$(BOUND_ARG)]])
: f_(f)[[]]
$if BOUND == 0 [[
{
]] $else [[
, $for BOUND_ARG , [[p$(BOUND_ARG)_(static_cast<typename BindType<P$(BOUND_ARG)>::StorageType>(p$(BOUND_ARG)))]] {
MaybeRefcount<IsMethod, P1>::AddRef(p1_);
]]
}
virtual ~InvokerStorage$(BOUND)() {
$if BOUND > 0 [[
MaybeRefcount<IsMethod, P1>::Release(p1_);
]]
}
Sig f_;
$for BOUND_ARG [[
typename BindType<P$(BOUND_ARG)>::StorageType p$(BOUND_ARG)_;
]]
};
]] $$ for BOUND
} // namespace internal
} // namespace base
#endif // BASE_BIND_INTERNAL_H_
|
