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
|
// Copyright 2016 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef EXTENSIONS_COMMON_API_MESSAGING_PORT_ID_H_
#define EXTENSIONS_COMMON_API_MESSAGING_PORT_ID_H_
#include <utility>
#include "base/unguessable_token.h"
#include "extensions/common/mojom/message_port.mojom-shared.h"
namespace extensions {
// A unique identifier for the Channel a port is on; i.e., the two-way
// communication between opener and receiver(s). We can use the pair of
// <context_id, port_number> which is the same between opener and receivers
// but unique amongst all other connections.
using ChannelId = std::pair<base::UnguessableToken, int>;
// A unique identifier for an extension port. The id is composed of three parts:
// - context_id: An UnguessableToken that uniquely identifies the creation
// context of the port.
// - port_number: A simple identifer that uniquely identifies the port *within
// the creation context*. That is, each creation context may
// have a port with number '1', but there should only be a single
// port with the number '1' in each.
// - is_opener: Whether or not this port id is for the opener port (false
// indicating it is the receiver port).
// Additionally, this also holds `serialization_format` which is the
// preferred mojom::SerializationFormat to be used for messages sent by this
// port. A few more notes:
// - There should only be a single existent opener port. That is, in all the
// contexts, there should only be one with a given context_id, port_number,
// and is_opener set to true. However, each port can have multiple receivers,
// thus there may be multiple ports with a given context_id, port_number, and
// is_opener set to false.
// - The context_id and port_number refer to the values at *creation*, and are
// conceptually immutable. Receiver ports will always have a context id other
// than the one they are hosted in (since we don't dispatch messages to the
// same context). Only in the case of opener ports do these identify the
// current context.
// - Context id and port number are set in the renderer process. Theoretically,
// this means that multiple contexts could have the same id. However, GUIDs
// are sufficiently random as to be globally unique in practice (the chance
// of a duplicate is about the same as the sun exploding right now).
// - The `serialization_format` for a port may sometimes differ from that of the
// Messages sent on the port. For example this can happen if a message can't
// be structure cloned in which case we fallback to JSON.
struct PortId {
// See class comments for the description of these fields.
base::UnguessableToken context_id;
int port_number = 0;
bool is_opener = false;
mojom::SerializationFormat serialization_format =
mojom::SerializationFormat::kJson;
PortId();
PortId(const base::UnguessableToken& context_id,
int port_number,
bool is_opener,
mojom::SerializationFormat format);
~PortId();
PortId(PortId&& other);
PortId(const PortId& other);
PortId& operator=(const PortId& other);
ChannelId GetChannelId() const {
return std::make_pair(context_id, port_number);
}
// Returns the identifier for the opposite port(s). That is, a call on a
// receiver port returns the ID of the opener, and a call on the opener port
// returns the ID of all receivers.
PortId GetOppositePortId() const {
return PortId(context_id, port_number, !is_opener, serialization_format);
}
bool operator==(const PortId& other) const;
bool operator<(const PortId& other) const;
};
} // namespace extensions
#endif // EXTENSIONS_COMMON_API_MESSAGING_PORT_ID_H_
|
