chromium/chrome/browser/net/referrer.h

// Copyright 2011 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// This class helps to remember what domains may be needed to be resolved when a
// navigation takes place to a given URL.  This information is gathered when a
// navigation to a subresource identifies a referring URL.
// When future navigations take place to known referrer sites, then we
// speculatively either pre-warm a TCP/IP conneciton, or at a minimum, resolve
// the host name via DNS.

// All access to this class is performed via the Predictor class, which only
// operates on the IO thread.

#ifndef CHROME_BROWSER_NET_REFERRER_H_
#define CHROME_BROWSER_NET_REFERRER_H_

#include <stdint.h>

#include <map>
#include <memory>

#include "base/time/time.h"
#include "base/values.h"
#include "net/base/host_port_pair.h"
#include "url/gurl.h"

namespace chrome_browser_net {

//------------------------------------------------------------------------------
// For each hostname in a Referrer, we have a ReferrerValue.  It indicates
// exactly how much value (re: latency reduction, or connection use) has
// resulted from having this entry.
class ReferrerValue { … };

//------------------------------------------------------------------------------
// A list of domain names to pre-resolve. The names are the keys to this map,
// and the values indicate the amount of benefit derived from having each name
// around.
SubresourceMap;

//------------------------------------------------------------------------------
// There is one Referrer instance for each hostname that has acted as an HTTP
// referer (note mispelling is intentional) for a hostname that was otherwise
// unexpectedly navgated towards ("unexpected" in the sense that the hostname
// was probably needed as a subresource of a page, and was not otherwise
// predictable until the content with the reference arrived).  Most typically,
// an outer page was a page fetched by the user, and this instance lists names
// in SubresourceMap which are subresources and that were needed to complete the
// rendering of the outer page.
class Referrer : public SubresourceMap { … };

}  // namespace chrome_browser_net

#endif  // CHROME_BROWSER_NET_REFERRER_H_