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// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/base/ime/ash/typing_session_manager.h"
#include <stddef.h>
#include <algorithm>
#include <cstring>
#include <set>
#include <utility>
#include "base/metrics/histogram_functions.h"
#include "base/time/clock.h"
namespace ash {
const uint64_t INACTIVITY_TIMEOUT_FOR_SESSION_IN_MS = 3000;
const uint64_t MIN_CHARACTERS_COMMITTED = 10;
const base::TimeDelta MIN_SESSION_DURATION_IN_MS = base::Seconds(1);
// TODO: We cannot assume that the time will always increase, it can decrease if
// system clock is explicitly set. Invalidate sessions where system clock
// decreases.
TypingSessionManager::TypingSessionManager(base::Clock* clock)
: characters_committed_this_session_count_(0),
clock_(clock ? clock : base::DefaultClock::GetInstance()),
is_active_(false) {
session_start_time_ = clock_->Now();
last_user_action_time_ = clock_->Now();
}
TypingSessionManager::TypingSessionManager(
const TypingSessionManager& typing_session_manager) {}
TypingSessionManager::~TypingSessionManager() {
EndAndRecordSession();
}
void TypingSessionManager::Heartbeat() {
base::Time current_time = clock_->Now();
// If too much time has passed, then end the previous session and
// start a new one.
if (is_active_) {
if (last_user_action_time_ +
base::Milliseconds(INACTIVITY_TIMEOUT_FOR_SESSION_IN_MS) <
current_time) {
EndAndRecordSession();
}
}
last_user_action_time_ = current_time;
// If no session is active, create a new one here.
if (!is_active_) {
is_active_ = true;
session_start_time_ = current_time;
characters_committed_this_session_count_ = 0;
}
}
// Note: only count characters as committed if the VK is enabled.
void TypingSessionManager::CommitCharacters(uint64_t character_count) {
Heartbeat();
characters_committed_this_session_count_ += character_count;
}
void TypingSessionManager::EndAndRecordSession() {
// Only record for sessions where at least 10 characters were entered
base::TimeDelta time_taken = last_user_action_time_ - session_start_time_;
if (characters_committed_this_session_count_ >= MIN_CHARACTERS_COMMITTED &&
time_taken >= MIN_SESSION_DURATION_IN_MS) {
base::UmaHistogramMediumTimes("InputMethod.SessionDuration", time_taken);
base::UmaHistogramCounts100000("InputMethod.CharactersPerSession",
characters_committed_this_session_count_);
}
// Reset the typing session
characters_committed_this_session_count_ = 0;
is_active_ = false;
session_start_time_ = clock_->Now();
last_user_action_time_ = clock_->Now();
}
} // namespace ash
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