components/previews/core/previews_experiments.h

// Copyright 2016 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 COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_
#define COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_

#include <string>
#include <utility>
#include <vector>

#include "base/time/time.h"
#include "net/nqe/effective_connection_type.h"

namespace previews {

enum class PreviewsType {
  // Used to indicate that there is no preview type.
  NONE = 0,

  // The user is shown an offline page as a preview.
  OFFLINE = 1,

  // Replace images with placeholders.
  LOFI = 2,

  // The user is shown a server lite page.
  LITE_PAGE = 3,

  // AMP version of the page is shown as a preview.
  AMP_REDIRECTION = 4,

  // Preview that disables JavaScript for the navigation.
  NOSCRIPT = 5,

  // Special value that indicates that no specific type is identified. This
  // might be used for checks or logging that applies to any type.
  UNSPECIFIED = 6,

  // Insert new enum values here. Keep values sequential to allow looping from
  // NONE+1 to LAST-1. Also add the enum to Previews.Types histogram suffix.
  LAST = 7,
};

typedef std::vector<std::pair<PreviewsType, int>> PreviewsTypeList;

// Gets the string representation of |type|.
std::string GetStringNameForType(PreviewsType type);

namespace params {

// The maximum number of recent previews navigations the black list looks at to
// determine if a host is blacklisted.
size_t MaxStoredHistoryLengthForPerHostBlackList();

// The maximum number of recent previews navigations the black list looks at to
// determine if all previews navigations are disallowed.
size_t MaxStoredHistoryLengthForHostIndifferentBlackList();

// The maximum number of hosts allowed in the in memory black list.
size_t MaxInMemoryHostsInBlackList();

// The number of recent navigations that were opted out of for a given host that
// would trigger that host to be blacklisted.
int PerHostBlackListOptOutThreshold();

// The number of recent navigations that were opted out of that would trigger
// all previews navigations to be disallowed.
int HostIndifferentBlackListOptOutThreshold();

// The amount of time a host remains blacklisted due to opt outs.
base::TimeDelta PerHostBlackListDuration();

// The amount of time all previews navigations are disallowed due to opt outs.
base::TimeDelta HostIndifferentBlackListPerHostDuration();

// The amount of time after any opt out that no previews should be shown.
base::TimeDelta SingleOptOutDuration();

// The amount of time that an offline page is considered fresh enough to be
// shown as a preview.
base::TimeDelta OfflinePreviewFreshnessDuration();

// The threshold of EffectiveConnectionType above which preview |type| will be
// triggered.
net::EffectiveConnectionType GetECTThresholdForPreview(
    previews::PreviewsType type);

// Whether any previews are allowed. Acts as a kill-switch or holdback check.
bool ArePreviewsAllowed();

// Whether the preview type is enabled.
bool IsOfflinePreviewsEnabled();
bool IsClientLoFiEnabled();
bool IsAMPRedirectionPreviewEnabled();
bool IsNoScriptPreviewsEnabled();

// The blacklist version for each preview type.
int OfflinePreviewsVersion();
int ClientLoFiVersion();
int AMPRedirectionPreviewsVersion();
int NoScriptPreviewsVersion();

// Whether server optimization hints are enabled.
bool IsOptimizationHintsEnabled();

// The threshold of EffectiveConnectionType above which Client Lo-Fi previews
// should not be served.
net::EffectiveConnectionType EffectiveConnectionTypeThresholdForClientLoFi();

// Returns the hosts that are blacklisted by the Client Lo-Fi field trial.
std::vector<std::string> GetBlackListedHostsForClientLoFiFieldTrial();

// For estimating NoScript data savings, this is the percentage factor to
// multiple by the network bytes for inflating the original_bytes count.
int NoScriptPreviewsInflationPercent();

// For estimating NoScript data savings, this is the number of bytes to
// for inflating the original_bytes count.
int NoScriptPreviewsInflationBytes();

}  // namespace params

}  // namespace previews

#endif  // COMPONENTS_PREVIEWS_CORE_PREVIEWS_EXPERIMENTS_H_