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
|
// Copyright 2015 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 IPC_IPC_MESSAGE_TEMPLATES_H_
#define IPC_IPC_MESSAGE_TEMPLATES_H_
#include <stdint.h>
#include <tuple>
#include <type_traits>
#include "base/logging.h"
#include "base/tuple.h"
#include "build/build_config.h"
#include "ipc/ipc_message.h"
#include "ipc/ipc_message_utils.h"
namespace IPC {
// This function is for all the async IPCs that don't pass an extra parameter
// using IPC_BEGIN_MESSAGE_MAP_WITH_PARAM.
template <typename ObjT, typename Method, typename P, typename Tuple>
void DispatchToMethod(ObjT* obj, Method method, P*, const Tuple& tuple) {
base::DispatchToMethod(obj, method, tuple);
}
template <typename ObjT,
typename Method,
typename P,
typename Tuple,
size_t... Ns>
void DispatchToMethodImpl(ObjT* obj,
Method method,
P* parameter,
const Tuple& tuple,
base::IndexSequence<Ns...>) {
// TODO(mdempsky): Apply UnwrapTraits like base::DispatchToMethod?
(obj->*method)(parameter, std::get<Ns>(tuple)...);
}
// The following function is for async IPCs which have a dispatcher with an
// extra parameter specified using IPC_BEGIN_MESSAGE_MAP_WITH_PARAM.
template <typename ObjT, typename P, typename... Args, typename... Ts>
typename std::enable_if<sizeof...(Args) == sizeof...(Ts)>::type
DispatchToMethod(ObjT* obj,
void (ObjT::*method)(P*, Args...),
P* parameter,
const std::tuple<Ts...>& tuple) {
DispatchToMethodImpl(obj, method, parameter, tuple,
base::MakeIndexSequence<sizeof...(Ts)>());
}
enum class MessageKind {
CONTROL,
ROUTED,
};
// Routing is a helper struct so MessageT's private common constructor has a
// different type signature than the public "int32_t routing_id" one.
struct Routing {
explicit Routing(int32_t id) : id(id) {}
int32_t id;
};
// We want to restrict MessageT's constructors so that a routing_id is always
// provided for ROUTED messages and never provided for CONTROL messages, so
// use the SFINAE technique from N4387's "Implementation Hint" section.
#if defined(COMPILER_MSVC)
// MSVC 2013 doesn't support default arguments for template member functions
// of templated classes, so there we have to rely on the DCHECKs instead.
// TODO(mdempsky): Reevaluate once MSVC 2015.
#define IPC_MESSAGET_SFINAE(x)
#else
#define IPC_MESSAGET_SFINAE(x) \
template <bool X = (x), typename std::enable_if<X, bool>::type = false>
#endif
// MessageT is the common template used for all user-defined message types.
// It's intended to be used via the macros defined in ipc_message_macros.h.
template <typename Meta,
typename InTuple = typename Meta::InTuple,
typename OutTuple = typename Meta::OutTuple>
class MessageT;
// Asynchronous message partial specialization.
template <typename Meta, typename... Ins>
class MessageT<Meta, std::tuple<Ins...>, void> : public Message {
public:
using Param = std::tuple<Ins...>;
enum { ID = Meta::ID };
// TODO(mdempsky): Remove. Uses of MyMessage::Schema::Param can be replaced
// with just MyMessage::Param.
using Schema = MessageT;
IPC_MESSAGET_SFINAE(Meta::kKind == MessageKind::CONTROL)
MessageT(const Ins&... ins) : MessageT(Routing(MSG_ROUTING_CONTROL), ins...) {
DCHECK(Meta::kKind == MessageKind::CONTROL) << Meta::kName;
}
IPC_MESSAGET_SFINAE(Meta::kKind == MessageKind::ROUTED)
MessageT(int32_t routing_id, const Ins&... ins)
: MessageT(Routing(routing_id), ins...) {
DCHECK(Meta::kKind == MessageKind::ROUTED) << Meta::kName;
}
static bool Read(const Message* msg, Param* p);
static void Log(std::string* name, const Message* msg, std::string* l);
template <class T, class S, class P, class Method>
static bool Dispatch(const Message* msg,
T* obj,
S* sender,
P* parameter,
Method func) {
Param p;
if (Read(msg, &p)) {
DispatchToMethod(obj, func, parameter, p);
return true;
}
return false;
}
private:
MessageT(Routing routing, const Ins&... ins);
};
// Synchronous message partial specialization.
template <typename Meta, typename... Ins, typename... Outs>
class MessageT<Meta, std::tuple<Ins...>, std::tuple<Outs...>>
: public SyncMessage {
public:
using SendParam = std::tuple<Ins...>;
using ReplyParam = std::tuple<Outs...>;
enum { ID = Meta::ID };
// TODO(mdempsky): Remove. Uses of MyMessage::Schema::{Send,Reply}Param can
// be replaced with just MyMessage::{Send,Reply}Param.
using Schema = MessageT;
IPC_MESSAGET_SFINAE(Meta::kKind == MessageKind::CONTROL)
MessageT(const Ins&... ins, Outs*... outs)
: MessageT(Routing(MSG_ROUTING_CONTROL), ins..., outs...) {
DCHECK(Meta::kKind == MessageKind::CONTROL) << Meta::kName;
}
IPC_MESSAGET_SFINAE(Meta::kKind == MessageKind::ROUTED)
MessageT(int32_t routing_id, const Ins&... ins, Outs*... outs)
: MessageT(Routing(routing_id), ins..., outs...) {
DCHECK(Meta::kKind == MessageKind::ROUTED) << Meta::kName;
}
static bool ReadSendParam(const Message* msg, SendParam* p);
static bool ReadReplyParam(const Message* msg, ReplyParam* p);
static void WriteReplyParams(Message* reply, const Outs&... outs);
static void Log(std::string* name, const Message* msg, std::string* l);
template <class T, class S, class P, class Method>
static bool Dispatch(const Message* msg,
T* obj,
S* sender,
P* parameter,
Method func) {
SendParam send_params;
bool ok = ReadSendParam(msg, &send_params);
Message* reply = SyncMessage::GenerateReply(msg);
if (ok) {
ReplyParam reply_params;
base::DispatchToMethod(obj, func, send_params, &reply_params);
WriteParam(reply, reply_params);
LogReplyParamsToMessage(reply_params, msg);
} else {
NOTREACHED() << "Error deserializing message " << msg->type();
reply->set_reply_error();
}
sender->Send(reply);
return ok;
}
template <class T, class P, class Method>
static bool DispatchDelayReply(const Message* msg,
T* obj,
P* parameter,
Method func) {
SendParam send_params;
bool ok = ReadSendParam(msg, &send_params);
Message* reply = SyncMessage::GenerateReply(msg);
if (ok) {
std::tuple<Message&> t = std::tie(*reply);
ConnectMessageAndReply(msg, reply);
base::DispatchToMethod(obj, func, send_params, &t);
} else {
NOTREACHED() << "Error deserializing message " << msg->type();
reply->set_reply_error();
obj->Send(reply);
}
return ok;
}
private:
MessageT(Routing routing, const Ins&... ins, Outs*... outs);
};
} // namespace IPC
#if defined(IPC_MESSAGE_IMPL)
#include "ipc/ipc_message_templates_impl.h"
#endif
#endif // IPC_IPC_MESSAGE_TEMPLATES_H_
|
