root/net/proxy/proxy_list.cc

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DEFINITIONS

This source file includes following definitions.
  1. Set
  2. SetSingleProxyServer
  3. AddProxyServer
  4. DeprioritizeBadProxies
  5. RemoveProxiesWithoutScheme
  6. Clear
  7. IsEmpty
  8. Equals
  9. Get
  10. SetFromPacString
  11. ToPacString
  12. ToValue
  13. Fallback
  14. AddProxyToRetryList
  15. UpdateRetryInfoOnFallback

// 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/proxy_list.h"

#include "base/callback.h"
#include "base/logging.h"
#include "base/rand_util.h"
#include "base/strings/string_tokenizer.h"
#include "base/time/time.h"
#include "base/values.h"
#include "net/proxy/proxy_server.h"

using base::TimeDelta;
using base::TimeTicks;

namespace net {

ProxyList::ProxyList() {
}

ProxyList::~ProxyList() {
}

void ProxyList::Set(const std::string& proxy_uri_list) {
  proxies_.clear();
  base::StringTokenizer str_tok(proxy_uri_list, ";");
  while (str_tok.GetNext()) {
    ProxyServer uri = ProxyServer::FromURI(
        str_tok.token_begin(), str_tok.token_end(), ProxyServer::SCHEME_HTTP);
    // Silently discard malformed inputs.
    if (uri.is_valid())
      proxies_.push_back(uri);
  }
}

void ProxyList::SetSingleProxyServer(const ProxyServer& proxy_server) {
  proxies_.clear();
  AddProxyServer(proxy_server);
}

void ProxyList::AddProxyServer(const ProxyServer& proxy_server) {
  if (proxy_server.is_valid())
    proxies_.push_back(proxy_server);
}

void ProxyList::DeprioritizeBadProxies(
    const ProxyRetryInfoMap& proxy_retry_info) {
  // Partition the proxy list in two:
  //   (1) the known bad proxies
  //   (2) everything else
  std::vector<ProxyServer> good_proxies;
  std::vector<ProxyServer> bad_proxies_to_try;

  std::vector<ProxyServer>::const_iterator iter = proxies_.begin();
  for (; iter != proxies_.end(); ++iter) {
    ProxyRetryInfoMap::const_iterator bad_proxy =
        proxy_retry_info.find(iter->ToURI());
    if (bad_proxy != proxy_retry_info.end()) {
      // This proxy is bad. Check if it's time to retry.
      if (bad_proxy->second.bad_until >= TimeTicks::Now()) {
        // still invalid.
        if (bad_proxy->second.try_while_bad)
          bad_proxies_to_try.push_back(*iter);
        continue;
      }
    }
    good_proxies.push_back(*iter);
  }

  // "proxies_ = good_proxies + bad_proxies"
  proxies_.swap(good_proxies);
  proxies_.insert(proxies_.end(), bad_proxies_to_try.begin(),
                  bad_proxies_to_try.end());
}

void ProxyList::RemoveProxiesWithoutScheme(int scheme_bit_field) {
  for (std::vector<ProxyServer>::iterator it = proxies_.begin();
       it != proxies_.end(); ) {
    if (!(scheme_bit_field & it->scheme())) {
      it = proxies_.erase(it);
      continue;
    }
    ++it;
  }
}

void ProxyList::Clear() {
  proxies_.clear();
}

bool ProxyList::IsEmpty() const {
  return proxies_.empty();
}

size_t ProxyList::size() const {
  return proxies_.size();
}

// Returns true if |*this| lists the same proxies as |other|.
bool ProxyList::Equals(const ProxyList& other) const {
  if (size() != other.size())
    return false;
  return proxies_ == other.proxies_;
}

const ProxyServer& ProxyList::Get() const {
  DCHECK(!proxies_.empty());
  return proxies_[0];
}

void ProxyList::SetFromPacString(const std::string& pac_string) {
  base::StringTokenizer entry_tok(pac_string, ";");
  proxies_.clear();
  while (entry_tok.GetNext()) {
    ProxyServer uri = ProxyServer::FromPacString(
        entry_tok.token_begin(), entry_tok.token_end());
    // Silently discard malformed inputs.
    if (uri.is_valid())
      proxies_.push_back(uri);
  }

  // If we failed to parse anything from the PAC results list, fallback to
  // DIRECT (this basically means an error in the PAC script).
  if (proxies_.empty()) {
    proxies_.push_back(ProxyServer::Direct());
  }
}

std::string ProxyList::ToPacString() const {
  std::string proxy_list;
  std::vector<ProxyServer>::const_iterator iter = proxies_.begin();
  for (; iter != proxies_.end(); ++iter) {
    if (!proxy_list.empty())
      proxy_list += ";";
    proxy_list += iter->ToPacString();
  }
  return proxy_list.empty() ? std::string() : proxy_list;
}

base::ListValue* ProxyList::ToValue() const {
  base::ListValue* list = new base::ListValue();
  for (size_t i = 0; i < proxies_.size(); ++i)
    list->AppendString(proxies_[i].ToURI());
  return list;
}

bool ProxyList::Fallback(ProxyRetryInfoMap* proxy_retry_info,
                         const BoundNetLog& net_log) {

  // TODO(eroman): It would be good if instead of removing failed proxies
  // from the list, we simply annotated them with the error code they failed
  // with. Of course, ProxyService::ReconsiderProxyAfterError() would need to
  // be given this information by the network transaction.
  //
  // The advantage of this approach is when the network transaction
  // fails, we could output the full list of proxies that were attempted, and
  // why each one of those failed (as opposed to just the last failure).
  //
  // And also, before failing the transaction wholesale, we could go back and
  // retry the "bad proxies" which we never tried to begin with.
  // (RemoveBadProxies would annotate them as 'expected bad' rather then delete
  // them from the list, so we would know what they were).

  if (proxies_.empty()) {
    NOTREACHED();
    return false;
  }
  UpdateRetryInfoOnFallback(proxy_retry_info, base::TimeDelta(), true,
                            ProxyServer(), net_log);

  // Remove this proxy from our list.
  proxies_.erase(proxies_.begin());
  return !proxies_.empty();
}

void ProxyList::AddProxyToRetryList(ProxyRetryInfoMap* proxy_retry_info,
                                    base::TimeDelta retry_delay,
                                    bool try_while_bad,
                                    const ProxyServer& proxy_to_retry,
                                    const BoundNetLog& net_log) const {
  // Mark this proxy as bad.
  std::string proxy_key = proxy_to_retry.ToURI();
  ProxyRetryInfoMap::iterator iter = proxy_retry_info->find(proxy_key);
  if (iter != proxy_retry_info->end()) {
    // TODO(nsylvain): This is not the first time we get this. We should
    // double the retry time. Bug 997660.
    iter->second.bad_until = TimeTicks::Now() + iter->second.current_delay;
  } else {
    ProxyRetryInfo retry_info;
    retry_info.current_delay = retry_delay;
    retry_info.bad_until = TimeTicks().Now() + retry_info.current_delay;
    retry_info.try_while_bad = try_while_bad;
    (*proxy_retry_info)[proxy_key] = retry_info;
  }
  net_log.AddEvent(NetLog::TYPE_PROXY_LIST_FALLBACK,
                   NetLog::StringCallback("bad_proxy", &proxy_key));
}

void ProxyList::UpdateRetryInfoOnFallback(
    ProxyRetryInfoMap* proxy_retry_info,
    base::TimeDelta retry_delay,
    bool reconsider,
    const ProxyServer& another_proxy_to_bypass,
    const BoundNetLog& net_log) const {
  // Time to wait before retrying a bad proxy server.
  if (retry_delay == base::TimeDelta()) {
#if defined(SPDY_PROXY_AUTH_ORIGIN)
    // Randomize the timeout over a range from one to five minutes.
    retry_delay =
        TimeDelta::FromMilliseconds(
            base::RandInt(1 * 60 * 1000, 5 * 60 * 1000));
#else
    retry_delay = TimeDelta::FromMinutes(5);
#endif
  }

  if (proxies_.empty()) {
    NOTREACHED();
    return;
  }

  if (!proxies_[0].is_direct()) {
    AddProxyToRetryList(proxy_retry_info, retry_delay, reconsider, proxies_[0],
                        net_log);

    // If an additional proxy to bypass is specified, add it to the retry map
    // as well.
    if (another_proxy_to_bypass.is_valid()) {
      AddProxyToRetryList(proxy_retry_info, retry_delay, reconsider,
                          another_proxy_to_bypass, net_log);
    }
  }
}

}  // namespace net

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