blob: ecfa08af6b8341b3a9bb06897a89baa42651c7b7 (
plain)
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
|
// 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 NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_
#define NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_
#include <stdint.h>
#include "base/gtest_prod_util.h"
#include "base/macros.h"
#include "base/threading/thread_checker.h"
#include "base/time/time.h"
#include "net/base/network_change_notifier.h"
namespace net {
struct NetworkQuality;
// NetworkQualityEstimator provides network quality estimates (quality of the
// full paths to all origins that have been connected to).
// The estimates are based on the observed organic traffic.
// A NetworkQualityEstimator instance is attached to URLRequestContexts and
// observes the traffic of URLRequests spawned from the URLRequestContexts.
// A single instance of NQE can be attached to multiple URLRequestContexts,
// thereby increasing the single NQE instance's accuracy by providing more
// observed traffic characteristics.
class NET_EXPORT_PRIVATE NetworkQualityEstimator
: public NetworkChangeNotifier::ConnectionTypeObserver {
public:
// Creates a new NetworkQualityEstimator.
NetworkQualityEstimator();
~NetworkQualityEstimator() override;
// Returns an estimate of the current network quality.
NetworkQuality GetEstimate() const;
// Notifies NetworkQualityEstimator that a response has been received.
// |prefilter_bytes_read| is the count of the bytes received prior to
// applying filters (e.g. decompression, SDCH) from request creation time
// until now.
void NotifyDataReceived(const URLRequest& request,
int64_t prefilter_bytes_read);
private:
FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
TestPeakKbpsFastestRTTUpdates);
FRIEND_TEST_ALL_PREFIXES(URLRequestTestHTTP, NetworkQualityEstimator);
// Tiny transfer sizes may give inaccurate throughput results.
// Minimum size of the transfer over which the throughput is computed.
static const int kMinTransferSizeInBytes = 10000;
// Minimum duration (in microseconds) of the transfer over which the
// throughput is computed.
static const int kMinRequestDurationMicroseconds = 1000;
// Construct a NetworkQualityEstimator instance allowing for test
// configuration.
// Registers for network type change notifications so estimates can be kept
// network specific.
// |allow_local_host_requests_for_tests| should only be true when testing
// against local HTTP server and allows the requests to local host to be
// used for network quality estimation.
explicit NetworkQualityEstimator(bool allow_local_host_requests_for_tests);
// NetworkChangeNotifier::ConnectionTypeObserver implementation.
void OnConnectionTypeChanged(
NetworkChangeNotifier::ConnectionType type) override;
// Determines if the requests to local host can be used in estimating the
// network quality. Set to true only for tests.
const bool allow_localhost_requests_;
// Time when last connection change was observed.
base::TimeTicks last_connection_change_;
// Last value passed to |OnConnectionTypeChanged|. This indicates the
// current connection type.
NetworkChangeNotifier::ConnectionType current_connection_type_;
// Set if any network data has been received since last connectivity change.
bool bytes_read_since_last_connection_change_;
// Fastest round-trip-time (RTT) since last connectivity change. RTT measured
// from URLRequest creation until first byte received.
base::TimeDelta fastest_RTT_since_last_connection_change_;
// Rough measurement of downlink peak Kbps witnessed since last connectivity
// change. The accuracy is decreased by ignoring these factors:
// 1) Multiple URLRequests can occur concurrently.
// 2) The transfer time includes at least one RTT while no bytes are read.
uint64_t peak_kbps_since_last_connection_change_;
base::ThreadChecker thread_checker_;
DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
};
} // namespace net
#endif // NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_
|
