chrome/browser/ui/webui/discards/site_data.mojom

// Copyright 2020 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.

module discards.mojom;

struct SiteDataFeature {
  // The cumulative observation time for this feature in seconds, set to 0 once
  // this feature has been observed.
  int64 observation_duration;
  // The time at which this feature has been used (set to 0 if it hasn't been
  // used), in seconds since epoch.
  int64 use_timestamp;
};

struct SiteDataPerformanceMeasurement {
  // A decaying average of the CPU usage measurements. Units: microseconds.
  float avg_cpu_usage_us;
  // A decaying average of the process footprint measurements. Units: kilobytes.
  float avg_footprint_kb;
  // A decaying average of the wall-clock load time duration of the tab.
  // Units: microseconds.
  float avg_load_duration_us;
};

struct SiteDataDatabaseSize {
  // The total number of rows in the database, or -1 if the value is not
  // available.
  int64 num_rows;

  // The total size of the database on disk in kilobytes, or -1 if the value
  // is not available.
  int64 on_disk_size_kb;
};

// The data stored for a given origin, this should mirror the
// SiteDataProto structure in
// performance_manager/persistence/site_data/site_data.proto.
struct SiteDataValue {
  // The last time this site has been in the loaded state, in seconds since
  // epoch.
  uint32 last_loaded;

  SiteDataFeature updates_favicon_in_background;
  SiteDataFeature updates_title_in_background;
  SiteDataFeature uses_audio_in_background;

  // Load time performance measurement estimates. This maintains a decaying
  // average of the resource usage of a page until shortly after it becomes
  // idle.
  SiteDataPerformanceMeasurement? load_time_estimates;
};

// Provides the key and miscellaneous in-memory only data pertaining to a
// row that potentially exists in a database.
struct SiteDataEntry {
  // The origin associated with this row.
  string origin;

  // This row is pending flush to disk.
  bool is_dirty;

  // NULL if the database entry doesn't exist on disk or in memory.
  SiteDataValue? value;
};

// Contains information about a specific set of SiteData entries.
struct SiteDataArray {
  // Contains the entries requested.
  array<SiteDataEntry> db_rows;
};

// Interface for providing information about the site data database. Lives in
// the browser process and is invoked in the renderer process via Javascript
// code running in the chrome://discards WebUI.
interface SiteDataProvider {
  // Returns the in-memory entries and the entries for the requested origins.
  // Note that any entry may take some time to load from disk, and so there may
  // not be any data for a given entry until on the second or subsequent
  // requests.
  GetSiteDataArray(
      array<string> explicitly_requested_origins) =>
          (SiteDataArray? result);

  // Returns the size of the database in number of rows and kilobytes.
  // Note that this may be fairly expensive to acquire, and so shouldn't be
  // called frequently.
  GetSiteDataDatabaseSize() =>
      (SiteDataDatabaseSize? db_size);
};