blob: e70fec154d5540b332bf98447d201ff8ab2f0f92 [file] [log] [blame]
// Copyright (c) 2013 The Chromium OS 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 "p2p/client/service_finder.h"
#include "p2p/common/clock.h"
#include <stdint.h>
#include <string>
#include <gtest/gtest_prod.h> // for FRIEND_TEST
#include <metrics/metrics_library.h>
namespace p2p {
namespace client {
// Interface for finding local peers willing to serve files.
class PeerSelector {
// Constructs the PeerSelector with the provided interfaces.
PeerSelector(ServiceFinder* finder, p2p::common::ClockInterface* clock);
// Finds an URL for the file |id| with at least |minimum_size| bytes and
// waits until the number of connections in the LAN has dropped below the
// required threshold. If there are no peers sharing this file with at least
// |minimum_size| bytes returns "" regardless of the number of connections in
// the LAN. On success, returns the URL found.
std::string GetUrlAndWait(const std::string& id, size_t minimum_size);
// Reports the following metrics based on the last call to GetUrlAndWait():
// * P2P.Client.LookupResult
// * P2P.Client.NumPeers
// * P2P.Client.Found.WaitingTimeSeconds
// * P2P.Client.Found.ConnectionCount
// * P2P.Client.Found.CandidateCount
// * P2P.Client.Vanished.WaitingTimeSeconds
// * P2P.Client.Canceled.WaitingTimeSeconds
// If there is an error reporting the metrics false is returned. Otherwise,
// returns true.
bool ReportMetrics(MetricsLibraryInterface* metrics_lib);
// Abort() cancels any ongoing and future call to GetUrlAndWait() making it
// return an empty string as soon as possible. This function is
// Async-Signal-Safe and can be called several times.
void Abort();
friend class PeerSelectorTest;
FRIEND_TEST(PeerSelectorTest, PickUrlForNonExistantId);
FRIEND_TEST(PeerSelectorTest, PickUrlForIdWithZeroBytes);
FRIEND_TEST(PeerSelectorTest, PickUrlForIdWithMinimumSize);
FRIEND_TEST(PeerSelectorTest, PickUrlFromTheFirstThird);
FRIEND_TEST(PeerSelectorTest, GetUrlAndWaitWhenThePeerGoesAway);
FRIEND_TEST(PeerSelectorTest, GetUrlDoesntWaitForSmallFiles);
FRIEND_TEST(PeerSelectorTest, ReportMetricsOnFilteredNetwork);
FRIEND_TEST(PeerSelectorTest, ReportMetricsWhenFound);
FRIEND_TEST(PeerSelectorTest, ReportMetricsWhenCanceled);
// file |id| with at least |minimum_size| bytes. If no peer is found meeting
// those conditions, an empty string is returned. Otherwise, the URL of the
// provided file is returned.
std::string PickUrlForId(const std::string& id, size_t minimum_size);
// The underlying service finder class used.
ServiceFinder* finder_;
// An interface to the system clock functions, used for unit testing.
p2p::common::ClockInterface* clock_;
enum LookupResult {
kFound, // The resource was found.
kNotFound, // The resource was not found.
kVanished, // The resource was found but vanished while waiting in line.
kCanceled, // The request was canceled with Abort().
kFiltered, // It was detected that mDNS was filtered.
// Note: Add new lookup results only above this line.
static std::string ToString(LookupResult lookup_result);
// The result of the last GetUrlAndWait() call.
LookupResult lookup_result_;
// Candidate files counter used for report metrics.
int candidate_files_count_;
// The number of connections of the peer picked by PickUrlForId().
int victim_connections_;
// The total number of peers in the network implementing P2P at the last
// ServiceFinder::Lookup() made by GetUrlAndWait().
int num_total_peers_;
// The elapsed time it took GetUrlAndWait() to return in seconds.
int64_t url_waiting_time_sec_;
// A flag used to signal the request was canceled.
volatile bool must_exit_now_;
} // namespace client
} // namespace p2p