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// Copyright (c) 2011 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/socket/stream_socket.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram.h"
#include "base/strings/string_number_conversions.h"
#include "base/values.h"
namespace net {
StreamSocket::UseHistory::UseHistory()
: was_ever_connected_(false),
was_used_to_convey_data_(false),
omnibox_speculation_(false),
subresource_speculation_(false) {
}
StreamSocket::UseHistory::~UseHistory() {
EmitPreconnectionHistograms();
}
void StreamSocket::UseHistory::Reset() {
EmitPreconnectionHistograms();
was_ever_connected_ = false;
was_used_to_convey_data_ = false;
// omnibox_speculation_ and subresource_speculation_ values
// are intentionally preserved.
}
void StreamSocket::UseHistory::set_was_ever_connected() {
DCHECK(!was_used_to_convey_data_);
was_ever_connected_ = true;
}
void StreamSocket::UseHistory::set_was_used_to_convey_data() {
DCHECK(was_ever_connected_);
was_used_to_convey_data_ = true;
}
void StreamSocket::UseHistory::set_subresource_speculation() {
DCHECK(was_ever_connected_);
// TODO(jar): We should transition to marking a socket (or stream) at
// construction time as being created for speculative reasons. This current
// approach of trying to track use of a socket to convey data can make
// mistakes when other sockets (such as ones sitting in the pool for a long
// time) are issued. Unused sockets can be left over when a when a set of
// connections to a host are made, and one is "unlucky" and takes so long to
// complete a connection, that another socket is used, and recycled before a
// second connection comes available. Similarly, re-try connections can leave
// an original (slow to connect socket) in the pool, and that can be issued
// to a speculative requester. In any cases such old sockets will fail when an
// attempt is made to used them!... and then it will look like a speculative
// socket was discarded without any user!?!?!
if (was_used_to_convey_data_)
return;
subresource_speculation_ = true;
}
void StreamSocket::UseHistory::set_omnibox_speculation() {
DCHECK(was_ever_connected_);
if (was_used_to_convey_data_)
return;
omnibox_speculation_ = true;
}
bool StreamSocket::UseHistory::was_used_to_convey_data() const {
DCHECK(!was_used_to_convey_data_ || was_ever_connected_);
return was_used_to_convey_data_;
}
void StreamSocket::UseHistory::EmitPreconnectionHistograms() const {
DCHECK(!subresource_speculation_ || !omnibox_speculation_);
// 0 ==> non-speculative, never connected.
// 1 ==> non-speculative never used (but connected).
// 2 ==> non-speculative and used.
// 3 ==> omnibox_speculative never connected.
// 4 ==> omnibox_speculative never used (but connected).
// 5 ==> omnibox_speculative and used.
// 6 ==> subresource_speculative never connected.
// 7 ==> subresource_speculative never used (but connected).
// 8 ==> subresource_speculative and used.
int result;
if (was_used_to_convey_data_)
result = 2;
else if (was_ever_connected_)
result = 1;
else
result = 0; // Never used, and not really connected.
if (omnibox_speculation_)
result += 3;
else if (subresource_speculation_)
result += 6;
UMA_HISTOGRAM_ENUMERATION("Net.PreconnectUtilization2", result, 9);
}
} // namespace net
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