Split NQE to multiple files

net/nqe/network_quality_estimator.h

 // 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_NQE_NETWORK_QUALITY_ESTIMATOR_H_
 #define NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
-#include <deque>
 #include <map>
 #include <memory>
 #include <string>
 #include <tuple>
 
 #include "base/compiler_specific.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 #include "net/base/net_export.h"
 #include "net/base/network_change_notifier.h"
+#include "net/nqe/cached_network_quality.h"
 #include "net/nqe/external_estimate_provider.h"
+#include "net/nqe/network_quality.h"
+#include "net/nqe/network_quality_observation.h"
+#include "net/nqe/network_quality_observation_source.h"
+#include "net/nqe/observation_buffer.h"
 #include "net/socket/socket_performance_watcher_factory.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace net {
 
 class URLRequest;
 
@@ skipping 22 matching lines @@
     EFFECTIVE_CONNECTION_TYPE_UNKNOWN = 0,
     EFFECTIVE_CONNECTION_TYPE_OFFLINE,
     EFFECTIVE_CONNECTION_TYPE_SLOW_2G,
     EFFECTIVE_CONNECTION_TYPE_2G,
     EFFECTIVE_CONNECTION_TYPE_3G,
     EFFECTIVE_CONNECTION_TYPE_4G,
     EFFECTIVE_CONNECTION_TYPE_BROADBAND,
     EFFECTIVE_CONNECTION_TYPE_LAST,
   };
 
-  // On Android, a Java counterpart will be generated for this enum.
-  // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.net
-  // GENERATED_JAVA_CLASS_NAME_OVERRIDE: NetworkQualityObservationSource
-  // GENERATED_JAVA_PREFIX_TO_STRIP:
-  enum ObservationSource {
-    // The observation was taken at the request layer, e.g., a round trip time
-    // is recorded as the time between the request being sent and the first byte
-    // being received.
-    URL_REQUEST,
-    // The observation is taken from TCP statistics maintained by the kernel.
-    TCP,
-    // The observation is taken at the QUIC layer.
-    QUIC,
-    // The observation is a previously cached estimate of the metric.
-    CACHED_ESTIMATE,
-    // The observation is derived from network connection information provided
-    // by the platform. For example, typical RTT and throughput values are used
-    // for a given type of network connection.
-    DEFAULT_FROM_PLATFORM,
-    // The observation came from a Chromium-external source.
-    EXTERNAL_ESTIMATE
-  };
-
   // Observes measurements of round trip time.
   class NET_EXPORT_PRIVATE RTTObserver {
    public:
     // Will be called when a new RTT observation is available. The round trip
     // time is specified in milliseconds. The time when the observation was
     // taken and the source of the observation are provided.
     virtual void OnRTTObservation(int32_t rtt_ms,
                                   const base::TimeTicks& timestamp,
-                                  ObservationSource source) = 0;
+                                  NetworkQualityObservationSource source) = 0;
 
    protected:
     RTTObserver() {}
     virtual ~RTTObserver() {}
 
    private:
     DISALLOW_COPY_AND_ASSIGN(RTTObserver);
   };
 
   // Observes measurements of throughput.
   class NET_EXPORT_PRIVATE ThroughputObserver {
    public:
     // Will be called when a new throughput observation is available.
     // Throughput is specified in kilobits per second.
-    virtual void OnThroughputObservation(int32_t throughput_kbps,
-                                         const base::TimeTicks& timestamp,
-                                         ObservationSource source) = 0;
+    virtual void OnThroughputObservation(
+        int32_t throughput_kbps,
+        const base::TimeTicks& timestamp,
+        NetworkQualityObservationSource source) = 0;
 
    protected:
     ThroughputObserver() {}
     virtual ~ThroughputObserver() {}
 
    private:
     DISALLOW_COPY_AND_ASSIGN(ThroughputObserver);
   };
 
   // Creates a new NetworkQualityEstimator.
@@ skipping 136 matching lines @@
 
   // Return a string equivalent to |type|.
   const char* GetNameForEffectiveConnectionType(
       EffectiveConnectionType type) const;
 
  private:
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, StoreObservations);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestAddObservation);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ObtainOperatingParams);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, HalfLifeParam);
-  FRIEND_TEST_ALL_PREFIXES(URLRequestTestHTTP, NetworkQualityEstimator);
-  FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
-                           PercentileSameTimestamps);
-  FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
-                           PercentileDifferentTimestamps);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ComputedPercentiles);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestCaching);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestLRUCacheMaximumSize);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestGetMedianRTTSince);
   FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest,
                            TestExternalEstimateProviderMergeEstimates);
 
   class SocketWatcher;
   class SocketWatcherFactory;
 
-  // NetworkQuality is used to cache the quality of a network connection.
-  class NET_EXPORT_PRIVATE NetworkQuality {
-   public:
-    NetworkQuality();
-    // |rtt| is the estimate of the round trip time.
-    // |downstream_throughput_kbps| is the estimate of the downstream
-    // throughput in kilobits per second.
-    NetworkQuality(const base::TimeDelta& rtt,
-                   int32_t downstream_throughput_kbps);
-    NetworkQuality(const NetworkQuality& other);
-    ~NetworkQuality();
-
-    NetworkQuality& operator=(const NetworkQuality& other);
-
-    // Returns the estimate of the round trip time.
-    const base::TimeDelta& rtt() const { return rtt_; }
-
-    // Returns the estimate of the downstream throughput in Kbps (Kilobits per
-    // second).
-    int32_t downstream_throughput_kbps() const {
-      return downstream_throughput_kbps_;
-    }
-
-   private:
-    // Estimated round trip time.
-    base::TimeDelta rtt_;
-
-    // Estimated downstream throughput in kilobits per second.
-    int32_t downstream_throughput_kbps_;
-  };
-
-  // CachedNetworkQuality stores the quality of a previously seen network.
-  class NET_EXPORT_PRIVATE CachedNetworkQuality {
-   public:
-    explicit CachedNetworkQuality(const NetworkQuality& network_quality);
-    CachedNetworkQuality(const CachedNetworkQuality& other);
-    ~CachedNetworkQuality();
-
-    // Returns the network quality associated with this cached entry.
-    const NetworkQuality& network_quality() const { return network_quality_; }
-
-    // Returns true if this cache entry was updated before
-    // |cached_network_quality|.
-    bool OlderThan(const CachedNetworkQuality& cached_network_quality) const;
-
-    // Time when this cache entry was last updated.
-    const base::TimeTicks last_update_time_;
-
-    // Quality of this cached network.
-    const NetworkQuality network_quality_;
-
-   private:
-    DISALLOW_ASSIGN(CachedNetworkQuality);
-  };
-
-  // Records observations of network quality metrics (such as round trip time
-  // or throughput), along with the time the observation was made. Observations
-  // can be made at several places in the network stack, thus the observation
-  // source is provided as well. ValueType must be numerical so that statistics
-  // such as median, average can be computed.
-  template <typename ValueType>
-  struct NET_EXPORT_PRIVATE Observation {
-    Observation(const ValueType& value,
-                base::TimeTicks timestamp,
-                ObservationSource source)
-        : value(value), timestamp(timestamp), source(source) {
-      DCHECK(!timestamp.is_null());
-    }
-    ~Observation() {}
-
-    // Value of the observation.
-    const ValueType value;
-
-    // Time when the observation was taken.
-    const base::TimeTicks timestamp;
-
-    // The source of the observation.
-    const ObservationSource source;
-  };
-
-  // Holds an observation and its weight.
-  template <typename ValueType>
-  struct NET_EXPORT_PRIVATE WeightedObservation {
-    WeightedObservation(ValueType value, double weight)
-        : value(value), weight(weight) {}
-    WeightedObservation(const WeightedObservation& other)
-        : WeightedObservation(other.value, other.weight) {}
-
-    WeightedObservation& operator=(const WeightedObservation& other) {
-      value = other.value;
-      weight = other.weight;
-      return *this;
-    }
-
-    // Required for sorting the samples in the ascending order of values.
-    bool operator<(const WeightedObservation& other) const {
-      return (value < other.value);
-    }
-
-    // Value of the sample.
-    ValueType value;
-
-    // Weight of the sample. This is computed based on how much time has passed
-    // since the sample was taken.
-    double weight;
-  };
-
-  // Stores observations sorted by time.
-  template <typename ValueType>
-  class NET_EXPORT_PRIVATE ObservationBuffer {
-   public:
-    explicit ObservationBuffer(double weight_multiplier_per_second);
-    ~ObservationBuffer();
-
-    // Adds |observation| to the buffer. The oldest observation in the buffer
-    // will be evicted to make room if the buffer is already full.
-    void AddObservation(const Observation<ValueType>& observation) {
-      DCHECK_LE(observations_.size(),
-                static_cast<size_t>(kMaximumObservationsBufferSize));
-      // Evict the oldest element if the buffer is already full.
-      if (observations_.size() == kMaximumObservationsBufferSize)
-        observations_.pop_front();
-
-      observations_.push_back(observation);
-      DCHECK_LE(observations_.size(),
-                static_cast<size_t>(kMaximumObservationsBufferSize));
-    }
-
-    // Clears the observations stored in this buffer.
-    void Clear() { observations_.clear(); }
-
-    // Returns true iff the |percentile| value of the observations in this
-    // buffer is available. Sets |result| to the computed |percentile|
-    // value among all observations since |begin_timestamp|. If the value is
-    // unavailable, false is returned and |result| is not modified. Percentile
-    // value is unavailable if all the values in observation buffer are older
-    // than |begin_timestamp|. |result| must not be null.
-    // |disallowed_observation_sources| is the list of observation sources that
-    // should be excluded when computing the percentile.
-    bool GetPercentile(
-        const base::TimeTicks& begin_timestamp,
-        ValueType* result,
-        int percentile,
-        const std::vector<ObservationSource>& disallowed_observation_sources)
-        const WARN_UNUSED_RESULT;
-
-   private:
-    FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, HalfLifeParam);
-
-    // Computes the weighted observations and stores them in
-    // |weighted_observations| sorted by ascending |WeightedObservation.value|.
-    // Only the observations with timestamp later than |begin_timestamp| are
-    // considered. Also, sets |total_weight| to the total weight of all
-    // observations. Should be called only when there is at least one
-    // observation in the buffer. |disallowed_observation_sources| is the list
-    // of observation sources that should be excluded when computing the
-    // weighted observations.
-    void ComputeWeightedObservations(
-        const base::TimeTicks& begin_timestamp,
-        std::vector<WeightedObservation<ValueType>>& weighted_observations,
-        double* total_weight,
-        const std::vector<ObservationSource>& disallowed_observation_sources)
-        const;
-
-    // Holds observations sorted by time, with the oldest observation at the
-    // front of the queue.
-    std::deque<Observation<ValueType>> observations_;
-
-    // The factor by which the weight of an observation reduces every second.
-    // For example, if an observation is 6 seconds old, its weight would be:
-    //     weight_multiplier_per_second_ ^ 6
-    // Calculated from |kHalfLifeSeconds| by solving the following equation:
-    //     weight_multiplier_per_second_ ^ kHalfLifeSeconds = 0.5
-    const double weight_multiplier_per_second_;
-
-    DISALLOW_COPY_AND_ASSIGN(ObservationBuffer);
-  };
-
   // Value of round trip time observations is in base::TimeDelta.
-  typedef net::NetworkQualityEstimator::Observation<base::TimeDelta>
-      RttObservation;
-  typedef net::NetworkQualityEstimator::ObservationBuffer<base::TimeDelta>
+  typedef nqe::internal::Observation<base::TimeDelta> RttObservation;
+  typedef nqe::internal::ObservationBuffer<base::TimeDelta>
       RttObservationBuffer;
 
   // Value of throughput observations is in kilobits per second.
-  typedef net::NetworkQualityEstimator::Observation<int32_t>
-      ThroughputObservation;
-  typedef net::NetworkQualityEstimator::ObservationBuffer<int32_t>
-      ThroughputObservationBuffer;
+  typedef nqe::internal::Observation<int32_t> ThroughputObservation;
+  typedef nqe::internal::ObservationBuffer<int32_t> ThroughputObservationBuffer;
 
   // This does not use a unordered_map or hash_map for code simplicity (key just
   // implements operator<, rather than hash and equality) and because the map is
   // tiny.
-  typedef std::map<NetworkID, CachedNetworkQuality> CachedNetworkQualities;
-
-  // Throughput is set to |kInvalidThroughput| if a valid value is
-  // unavailable. Readers should discard throughput value if it is set to
-  // |kInvalidThroughput|.
-  static const int32_t kInvalidThroughput;
+  typedef std::map<NetworkID, nqe::internal::CachedNetworkQuality>
+      CachedNetworkQualities;
 
   // 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;
 
   // Minimum valid value of the variation parameter that holds RTT (in
   // milliseconds) values.
   static const int kMinimumRTTVariationParameterMsec = 1;
 
   // Minimum valid value of the variation parameter that holds throughput (in
   // kilobits per second) values.
   static const int kMinimumThroughputVariationParameterKbps = 1;
 
   // Maximum size of the cache that holds network quality estimates.
   // Smaller size may reduce the cache hit rate due to frequent evictions.
   // Larger size may affect performance.
   static const size_t kMaximumNetworkQualityCacheSize = 10;
 
-  // Maximum number of observations that can be held in the ObservationBuffer.
-  static const size_t kMaximumObservationsBufferSize = 300;
-
   // Time duration (in milliseconds) after which the estimate provided by
   // external estimate provider is considered stale.
   static const int kExternalEstimateProviderFreshnessDurationMsec =
       5 * 60 * 1000;
 
   // Returns the RTT value to be used when the valid RTT is unavailable. Readers
   // should discard RTT if it is set to the value returned by |InvalidRTT()|.
   static const base::TimeDelta InvalidRTT();
 
   // Notifies |this| of a new transport layer RTT.
@@ skipping 22 matching lines @@
   // Returns an estimate of network quality at the specified |percentile|.
   // |disallowed_observation_sources| is the list of observation sources that
   // should be excluded when computing the percentile.
   // Only the observations later than |begin_timestamp| are taken into account.
   // |percentile| must be between 0 and 100 (both inclusive) with higher
   // percentiles indicating less performant networks. For example, if
   // |percentile| is 90, then the network is expected to be faster than the
   // returned estimate with 0.9 probability. Similarly, network is expected to
   // be slower than the returned estimate with 0.1 probability.
   base::TimeDelta GetRTTEstimateInternal(
-      const std::vector<ObservationSource>& disallowed_observation_sources,
+      const std::vector<NetworkQualityObservationSource>&
+          disallowed_observation_sources,
       const base::TimeTicks& begin_timestamp,
       int percentile) const;
   int32_t GetDownlinkThroughputKbpsEstimateInternal(
       const base::TimeTicks& begin_timestamp,
       int percentile) const;
 
   // Returns the current network ID checking by calling the platform APIs.
   // Virtualized for testing.
   virtual NetworkID GetCurrentNetworkID() const;
 
@@ skipping 48 matching lines @@
 
   // ID of the current network.
   NetworkID current_network_id_;
 
   // Peak network quality (fastest round-trip-time (RTT) and highest
   // downstream throughput) measured since last connectivity change. RTT is
   // measured from time the request is sent until the first byte received.
   // The accuracy is decreased by ignoring these factors:
   // 1) Multiple URLRequests can occur concurrently.
   // 2) Includes server processing time.
-  NetworkQuality peak_network_quality_;
+  nqe::internal::NetworkQuality peak_network_quality_;
 
   // Cache that stores quality of previously seen networks.
   CachedNetworkQualities cached_network_qualities_;
 
   // Buffer that holds throughput observations (in kilobits per second) sorted
   // by timestamp.
   ThroughputObservationBuffer downstream_throughput_kbps_observations_;
 
   // Buffer that holds RTT observations sorted by timestamp.
   RttObservationBuffer rtt_observations_;
 
   // Default network quality observations obtained from the network quality
   // estimator field trial parameters. The observations are indexed by
   // ConnectionType.
-  NetworkQuality
+  nqe::internal::NetworkQuality
       default_observations_[NetworkChangeNotifier::CONNECTION_LAST + 1];
 
   // Thresholds for different effective connection types obtained from field
   // trial variation params. These thresholds encode how different connection
   // types behave in general. In future, complex encodings (e.g., curve
   // fitting) may be used.
-  NetworkQuality connection_thresholds_[EFFECTIVE_CONNECTION_TYPE_LAST];
+  nqe::internal::NetworkQuality
+      connection_thresholds_[EFFECTIVE_CONNECTION_TYPE_LAST];
 
   // Estimated network quality. Updated on mainframe requests.
-  NetworkQuality estimated_median_network_quality_;
+  nqe::internal::NetworkQuality estimated_median_network_quality_;
 
   // ExternalEstimateProvider that provides network quality using operating
   // system APIs. May be NULL.
   const std::unique_ptr<ExternalEstimateProvider> external_estimate_provider_;
 
   // Observer lists for round trip times and throughput measurements.
   base::ObserverList<RTTObserver> rtt_observer_list_;
   base::ObserverList<ThroughputObserver> throughput_observer_list_;
 
   std::unique_ptr<SocketPerformanceWatcherFactory> watcher_factory_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<NetworkQualityEstimator> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator);
 };
 
 }  // namespace net
 
 #endif  // NET_NQE_NETWORK_QUALITY_ESTIMATOR_H_