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
|
// Copyright 2014 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 THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_
#define THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_
#include <stddef.h>
#include <stdint.h>
#include <ostream>
#include "base/containers/hash_tables.h"
#include "base/gtest_prod_util.h"
#include "mojo/public/cpp/system/macros.h"
#include "third_party/mojo/src/mojo/edk/system/system_impl_export.h"
namespace mojo {
namespace system {
// ChannelEndpointId -----------------------------------------------------------
class LocalChannelEndpointIdGenerator;
FORWARD_DECLARE_TEST(LocalChannelEndpointIdGeneratorTest, WrapAround);
FORWARD_DECLARE_TEST(RemoteChannelEndpointIdGeneratorTest, WrapAround);
// Represents an ID for an endpoint (i.e., one side of a message pipe) on a
// |Channel|. This class must be POD.
//
// Note: The terminology "remote" for a |ChannelEndpointId| means a destination
// ID that was actually allocated by the sender, or similarly a source ID that
// was allocated by the receiver.
//
// From the standpoint of the |Channel| with such a remote ID in its endpoint
// table, such an ID is a "remotely-allocated local ID". From the standpoint of
// the |Channel| allocating such a remote ID (for its peer |Channel|), it's a
// "locally-allocated remote ID".
class MOJO_SYSTEM_IMPL_EXPORT ChannelEndpointId {
public:
ChannelEndpointId() : value_(0) {}
ChannelEndpointId(const ChannelEndpointId& other) : value_(other.value_) {}
// Returns the local ID to use for the first message pipe endpoint on a
// channel.
static ChannelEndpointId GetBootstrap() { return ChannelEndpointId(1); }
bool operator==(const ChannelEndpointId& other) const {
return value_ == other.value_;
}
bool operator!=(const ChannelEndpointId& other) const {
return !operator==(other);
}
// So that we can be used in |std::map|, etc.
bool operator<(const ChannelEndpointId& other) const {
return value_ < other.value_;
}
bool is_valid() const { return !!value_; }
bool is_remote() const { return !!(value_ & kRemoteFlag); }
const uint32_t& value() const { return value_; }
// Flag set in |value()| if this is a remote ID.
static const uint32_t kRemoteFlag = 0x80000000u;
private:
friend class LocalChannelEndpointIdGenerator;
FRIEND_TEST_ALL_PREFIXES(LocalChannelEndpointIdGeneratorTest, WrapAround);
friend class RemoteChannelEndpointIdGenerator;
FRIEND_TEST_ALL_PREFIXES(RemoteChannelEndpointIdGeneratorTest, WrapAround);
explicit ChannelEndpointId(uint32_t value) : value_(value) {}
uint32_t value_;
// Copying and assignment allowed.
};
// This wrapper should add no overhead.
// TODO(vtl): Rewrite |sizeof(uint32_t)| as |sizeof(ChannelEndpointId::value)|
// once we have sufficient C++11 support.
static_assert(sizeof(ChannelEndpointId) == sizeof(uint32_t),
"ChannelEndpointId has incorrect size");
// So logging macros and |DCHECK_EQ()|, etc. work.
MOJO_SYSTEM_IMPL_EXPORT inline std::ostream& operator<<(
std::ostream& out,
const ChannelEndpointId& channel_endpoint_id) {
return out << channel_endpoint_id.value();
}
// LocalChannelEndpointIdGenerator ---------------------------------------------
// A generator for "new" local |ChannelEndpointId|s. It does not track
// used/existing IDs; that must be done separately. (This class is not
// thread-safe.)
class MOJO_SYSTEM_IMPL_EXPORT LocalChannelEndpointIdGenerator {
public:
LocalChannelEndpointIdGenerator()
: next_(ChannelEndpointId::GetBootstrap()) {}
ChannelEndpointId GetNext();
private:
FRIEND_TEST_ALL_PREFIXES(LocalChannelEndpointIdGeneratorTest, WrapAround);
ChannelEndpointId next_;
MOJO_DISALLOW_COPY_AND_ASSIGN(LocalChannelEndpointIdGenerator);
};
// RemoteChannelEndpointIdGenerator --------------------------------------------
// A generator for "new" remote |ChannelEndpointId|s, for |Channel|s to
// locally allocate remote IDs. (See the comment above |ChannelEndpointId| for
// an explanatory note.) It does not track used/existing IDs; that must be done
// separately. (This class is not thread-safe.)
class MOJO_SYSTEM_IMPL_EXPORT RemoteChannelEndpointIdGenerator {
public:
RemoteChannelEndpointIdGenerator() : next_(ChannelEndpointId::kRemoteFlag) {}
ChannelEndpointId GetNext();
private:
FRIEND_TEST_ALL_PREFIXES(RemoteChannelEndpointIdGeneratorTest, WrapAround);
ChannelEndpointId next_;
MOJO_DISALLOW_COPY_AND_ASSIGN(RemoteChannelEndpointIdGenerator);
};
} // namespace system
} // namespace mojo
// Define "hash" functions for |ChannelEndpointId|s, so they can be used in hash
// tables.
// TODO(vtl): Once we can use |std::unordered_{map,set}|, update this (and
// remove the base/containers/hash_tables.h include).
namespace BASE_HASH_NAMESPACE {
template <>
struct hash<mojo::system::ChannelEndpointId> {
size_t operator()(mojo::system::ChannelEndpointId channel_endpoint_id) const {
return static_cast<size_t>(channel_endpoint_id.value());
}
};
} // namespace BASE_HASH_NAMESPACE
#endif // THIRD_PARTY_MOJO_SRC_MOJO_EDK_SYSTEM_CHANNEL_ENDPOINT_ID_H_
|
