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
|
// Copyright (c) 2012 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.
#include "net/proxy/polling_proxy_config_service.h"
#include "base/bind.h"
#include "base/location.h"
#include "base/memory/scoped_ptr.h"
#include "base/message_loop/message_loop_proxy.h"
#include "base/observer_list.h"
#include "base/synchronization/lock.h"
#include "base/threading/worker_pool.h"
#include "net/proxy/proxy_config.h"
namespace net {
// Reference-counted wrapper that does all the work (needs to be
// reference-counted since we post tasks between threads; may outlive
// the parent PollingProxyConfigService).
class PollingProxyConfigService::Core
: public base::RefCountedThreadSafe<PollingProxyConfigService::Core> {
public:
Core(base::TimeDelta poll_interval,
GetConfigFunction get_config_func)
: get_config_func_(get_config_func),
poll_interval_(poll_interval),
have_initialized_origin_loop_(false),
has_config_(false),
poll_task_outstanding_(false),
poll_task_queued_(false) {
}
// Called when the parent PollingProxyConfigService is destroyed
// (observers should not be called past this point).
void Orphan() {
base::AutoLock l(lock_);
origin_loop_proxy_ = NULL;
}
bool GetLatestProxyConfig(ProxyConfig* config) {
LazyInitializeOriginLoop();
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
OnLazyPoll();
// If we have already retrieved the proxy settings (on worker thread)
// then return what we last saw.
if (has_config_) {
*config = last_config_;
return true;
}
return false;
}
void AddObserver(Observer* observer) {
LazyInitializeOriginLoop();
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
observers_.AddObserver(observer);
}
void RemoveObserver(Observer* observer) {
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
observers_.RemoveObserver(observer);
}
// Check for a new configuration if enough time has elapsed.
void OnLazyPoll() {
LazyInitializeOriginLoop();
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
if (last_poll_time_.is_null() ||
(base::TimeTicks::Now() - last_poll_time_) > poll_interval_) {
CheckForChangesNow();
}
}
void CheckForChangesNow() {
LazyInitializeOriginLoop();
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
if (poll_task_outstanding_) {
// Only allow one task to be outstanding at a time. If we get a poll
// request while we are busy, we will defer it until the current poll
// completes.
poll_task_queued_ = true;
return;
}
last_poll_time_ = base::TimeTicks::Now();
poll_task_outstanding_ = true;
poll_task_queued_ = false;
base::WorkerPool::PostTask(
FROM_HERE,
base::Bind(&Core::PollOnWorkerThread, this, get_config_func_),
true);
}
private:
friend class base::RefCountedThreadSafe<Core>;
~Core() {}
void PollOnWorkerThread(GetConfigFunction func) {
ProxyConfig config;
func(&config);
base::AutoLock l(lock_);
if (origin_loop_proxy_.get()) {
origin_loop_proxy_->PostTask(
FROM_HERE, base::Bind(&Core::GetConfigCompleted, this, config));
}
}
// Called after the worker thread has finished retrieving a configuration.
void GetConfigCompleted(const ProxyConfig& config) {
DCHECK(poll_task_outstanding_);
poll_task_outstanding_ = false;
if (!origin_loop_proxy_.get())
return; // Was orphaned (parent has already been destroyed).
DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
if (!has_config_ || !last_config_.Equals(config)) {
// If the configuration has changed, notify the observers.
has_config_ = true;
last_config_ = config;
FOR_EACH_OBSERVER(Observer, observers_,
OnProxyConfigChanged(config,
ProxyConfigService::CONFIG_VALID));
}
if (poll_task_queued_)
CheckForChangesNow();
}
void LazyInitializeOriginLoop() {
// TODO(eroman): Really this should be done in the constructor, but right
// now chrome is constructing the ProxyConfigService on the
// UI thread so we can't cache the IO thread for the purpose
// of DCHECKs until the first call is made.
if (!have_initialized_origin_loop_) {
origin_loop_proxy_ = base::MessageLoopProxy::current();
have_initialized_origin_loop_ = true;
}
}
GetConfigFunction get_config_func_;
ObserverList<Observer> observers_;
ProxyConfig last_config_;
base::TimeTicks last_poll_time_;
base::TimeDelta poll_interval_;
base::Lock lock_;
scoped_refptr<base::MessageLoopProxy> origin_loop_proxy_;
bool have_initialized_origin_loop_;
bool has_config_;
bool poll_task_outstanding_;
bool poll_task_queued_;
};
void PollingProxyConfigService::AddObserver(Observer* observer) {
core_->AddObserver(observer);
}
void PollingProxyConfigService::RemoveObserver(Observer* observer) {
core_->RemoveObserver(observer);
}
ProxyConfigService::ConfigAvailability
PollingProxyConfigService::GetLatestProxyConfig(ProxyConfig* config) {
return core_->GetLatestProxyConfig(config) ? CONFIG_VALID : CONFIG_PENDING;
}
void PollingProxyConfigService::OnLazyPoll() {
core_->OnLazyPoll();
}
PollingProxyConfigService::PollingProxyConfigService(
base::TimeDelta poll_interval,
GetConfigFunction get_config_func)
: core_(new Core(poll_interval, get_config_func)) {
}
PollingProxyConfigService::~PollingProxyConfigService() {
core_->Orphan();
}
void PollingProxyConfigService::CheckForChangesNow() {
core_->CheckForChangesNow();
}
} // namespace net
|
