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
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */
#ifndef mozilla_ipc_IPCStreamUtils_h
#define mozilla_ipc_IPCStreamUtils_h
#include "mozilla/ipc/IPCStream.h"
#include "nsIInputStream.h"
namespace mozilla {
namespace dom {
class nsIContentChild;
class PContentParent;
}
namespace ipc {
class PBackgroundChild;
class PBackgroundParent;
// Deserialize an IPCStream received from an actor call. These methods
// work in both the child and parent.
already_AddRefed<nsIInputStream>
DeserializeIPCStream(const IPCStream& aValue);
already_AddRefed<nsIInputStream>
DeserializeIPCStream(const OptionalIPCStream& aValue);
// RAII helper class that serializes an nsIInputStream into an IPCStream struct.
// Any file descriptor or PSendStream actors are automatically managed
// correctly.
//
// Here is a simple example:
//
// // in ipdl file
// Protocol PMyStuff
// {
// parent:
// async DoStuff(IPCStream aStream);
// child:
// async StuffDone(IPCStream aStream);
// };
//
// // in child c++ code
// void CallDoStuff(PMyStuffChild* aActor, nsIInputStream* aStream)
// {
// AutoIPCStream autoStream;
// autoStream.Serialize(aStream, aActor->Manager());
// aActor->SendDoStuff(autoStream.TakeValue());
// }
//
// // in parent c++ code
// bool
// MyStuffParent::RecvDoStuff(const IPCStream& aIPCStream) {
// nsCOMPtr<nsIInputStream> stream = DeserializeIPCStream(aIPCStream);
// // Do something with stream...
//
// // You can also serialize streams from parent-to-child as long as
// // they don't require PSendStream actor support.
// AutoIPCStream anotherStream;
// anotherStream.Serialize(mFileStream, Manager());
// SendStuffDone(anotherStream.TakeValue());
// }
//
// The AutoIPCStream RAII class may also be used if your stream is embedded
// in a more complex IPDL structure. In this case you attach the AutoIPCStream
// to the embedded IPCStream and call TakeValue() after you pass the structure.
// For example:
//
// // in ipdl file
// struct Stuff
// {
// IPCStream stream;
// nsCString name;
// };
//
// Protocol PMyStuff
// {
// parent:
// async DoStuff(Stuff aStream);
// };
//
// // in child c++ code
// void CallDoStuff(PMyStuffChild* aActor, nsIInputStream* aStream)
// {
// Stuff stuff;
// AutoIPCStream autoStream(stuff.stream()); // attach to IPCStream here
// autoStream.Serialize(aStream, aActor->Manager());
// aActor->SendDoStuff(stuff);
// autoStream.TakeValue(); // call take value after send
// }
//
// // in parent c++ code
// bool
// MyStuffParent::RecvDoStuff(const Stuff& aStuff) {
// nsCOMPtr<nsIInputStream> stream = DeserializeIPCStream(aStuff.stream());
// /* do something with the nsIInputStream */
// }
//
// The AutoIPCStream class also supports OptionalIPCStream values. As long as
// you did not initialize the object with a non-optional IPCStream, you can call
// TakeOptionalValue() instead.
//
// The AutoIPCStream class can also be used to serialize nsIInputStream objects
// on the parent side to send to the child. Currently, however, this only
// works for directly serializable stream types. The PSendStream actor mechanism
// is not supported in this direction yet.
//
// Like SerializeInputStream(), the AutoIPCStream will crash if
// serialization cannot be completed.
//
// NOTE: This is not a MOZ_STACK_CLASS so that it can be more easily integrated
// with complex ipdl structures. For example, you may want to create an
// array of RAII AutoIPCStream objects or build your own wrapping
// RAII object to handle other actors that need to be cleaned up.
class AutoIPCStream final
{
OptionalIPCStream mInlineValue;
IPCStream* mValue;
OptionalIPCStream* mOptionalValue;
bool mTaken;
bool
IsSet() const;
public:
// Implicitly create an OptionalIPCStream value. Either
// TakeValue() or TakeOptionalValue() can be used.
AutoIPCStream();
// Wrap an existing IPCStream. Only TakeValue() may be
// used. If a nullptr nsIInputStream is passed to SerializeOrSend() then
// a crash will be forced.
explicit AutoIPCStream(IPCStream& aTarget);
// Wrap an existing OptionalIPCStream. Either TakeValue()
// or TakeOptionalValue can be used.
explicit AutoIPCStream(OptionalIPCStream& aTarget);
~AutoIPCStream();
// Serialize the input stream or create a SendStream actor using the PContent
// manager. If neither of these succeed, then crash. This should only be
// used on the main thread.
void
Serialize(nsIInputStream* aStream, dom::nsIContentChild* aManager);
// Serialize the input stream or create a SendStream actor using the
// PBackground manager. If neither of these succeed, then crash. This can
// be called on the main thread or Worker threads.
void
Serialize(nsIInputStream* aStream, PBackgroundChild* aManager);
// Serialize the input stream. A PSendStream cannot be used when going
// from parent-to-child.
void
Serialize(nsIInputStream* aStream, dom::PContentParent* aManager);
// Serialize the input stream. A PSendStream cannot be used when going
// from parent-to-child.
void
Serialize(nsIInputStream* aStream, PBackgroundParent* aManager);
// Get the IPCStream as a non-optional value. This will
// assert if a stream has not been serialized or if it has already been taken.
// This should only be called if the value is being, or has already been, sent
// to the parent
IPCStream&
TakeValue();
// Get the OptionalIPCStream value. This will assert if
// the value has already been taken. This should only be called if the value
// is being, or has already been, sent to the parent
OptionalIPCStream&
TakeOptionalValue();
};
} // namespace ipc
} // namespace mozilla
#endif // mozilla_ipc_IPCStreamUtils_h
|
