mojo/services/flog/interfaces/flog.mojom

// 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.

[DartPackage="mojo_services"]
module mojo.flog;

// TODO(dalesat): Move out of media to somewhere more generic.

// Exposed by the log service to enable creation and consumption of logs.
[ServiceName="mojo::flog::FlogService"]
interface FlogService {
  // Creates a new logger.
  CreateLogger(FlogLogger& logger, string label);

  // Gets the descriptions of all logs.
  GetLogDescriptions() => (array<FlogDescription> descriptions);

  // Gets a reader for the specified log.
  CreateReader(FlogReader& reader, uint32 log_id);
};

// A logger that logs messages regarding multiple channels.
interface FlogLogger {
  // Logs the creation of a channel.
  LogChannelCreation(int64 time_us, uint32 channel_id, string type_name);

  // Logs a message sent to an existing channel.
  LogChannelMessage(int64 time_us, uint32 channel_id, array<uint8> data);

  // Logs the deletion of a channel.
  LogChannelDeletion(int64 time_us, uint32 channel_id);
};

// A reader that reads messages from one or more logs.
interface FlogReader {
  // Gets entries from the log starting and the specified index (entries are
  // indexed starting at 0). If the log is open, the callback will be called
  // when max_count entries are avaiable starting at start_index. If the log
  // is closed, the callback will be called immediately with as many entries
  // as are available starting at start_index and not exceeding max_count
  // entries. entry_count and open refer to the entire log at the time the
  // callback occurred.
  GetEntries(uint32 start_index, uint32 max_count) =>
      (array<FlogEntry> entries, uint32 entry_count, bool open);
};

struct FlogDescription {
  string label;
  uint32 log_id;
  uint32 entry_count;
  int64 start_time_us;
  int64 stop_time_us;
  bool open;
};

struct FlogEntry {
  int64 time_us;
  uint32 log_id;
  uint32 channel_id;
  FlogEntryDetails? details;
};

union FlogEntryDetails {
  FlogChannelCreationEntryDetails channel_creation;
  FlogChannelMessageEntryDetails channel_message;
};

struct FlogChannelCreationEntryDetails {
  string type_name;
};

struct FlogChannelMessageEntryDetails {
  array<uint8> data;
};