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// 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.
#include "components/arc/arc_session_runner.h"
#include "base/logging.h"
#include "base/memory/ref_counted.h"
#include "base/task_runner.h"
namespace arc {
namespace {
constexpr base::TimeDelta kDefaultRestartDelay =
base::TimeDelta::FromSeconds(5);
} // namespace
ArcSessionRunner::ArcSessionRunner(const ArcSessionFactory& factory)
: restart_delay_(kDefaultRestartDelay),
factory_(factory),
weak_ptr_factory_(this) {}
ArcSessionRunner::~ArcSessionRunner() {
DCHECK(thread_checker_.CalledOnValidThread());
if (arc_session_)
arc_session_->RemoveObserver(this);
}
void ArcSessionRunner::AddObserver(Observer* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
observer_list_.AddObserver(observer);
}
void ArcSessionRunner::RemoveObserver(Observer* observer) {
DCHECK(thread_checker_.CalledOnValidThread());
observer_list_.RemoveObserver(observer);
}
void ArcSessionRunner::RequestStart() {
DCHECK(thread_checker_.CalledOnValidThread());
// Consecutive RequestStart() call. Do nothing.
if (run_requested_)
return;
VLOG(1) << "Session started";
run_requested_ = true;
// Here |run_requested_| transitions from false to true. So, |restart_timer_|
// must be stopped (either not even started, or has been cancelled in
// previous RequestStop() call).
DCHECK(!restart_timer_.IsRunning());
if (arc_session_) {
// In this case, RequestStop() was called, and before |arc_session_| had
// finished stopping, RequestStart() was called. Do nothing in that case,
// since when |arc_session_| does actually stop, OnSessionStopped() will
// be called, where it should automatically restart.
DCHECK_EQ(state_, State::STOPPING);
} else {
DCHECK_EQ(state_, State::STOPPED);
StartArcSession();
}
}
void ArcSessionRunner::RequestStop() {
DCHECK(thread_checker_.CalledOnValidThread());
// Consecutive RequestStop() call. Do nothing.
if (!run_requested_)
return;
VLOG(1) << "Session ended";
run_requested_ = false;
if (arc_session_) {
// The |state_| could be either STARTING, RUNNING or STOPPING.
DCHECK_NE(state_, State::STOPPED);
if (state_ == State::STOPPING) {
// STOPPING is found in the senario of "RequestStart() -> RequestStop()
// -> RequestStart() -> RequestStop()" case.
// In the first RequestStop() call, |state_| is set to STOPPING,
// and in the second RequestStop() finds it (so this is the second call).
// In that case, ArcSession::Stop() is already called, so do nothing.
return;
}
state_ = State::STOPPING;
arc_session_->Stop();
} else {
DCHECK_EQ(state_, State::STOPPED);
// In case restarting is in progress, cancel it.
restart_timer_.Stop();
}
}
void ArcSessionRunner::OnShutdown() {
DCHECK(thread_checker_.CalledOnValidThread());
VLOG(1) << "OnShutdown";
run_requested_ = false;
restart_timer_.Stop();
if (arc_session_) {
DCHECK_NE(state_, State::STOPPED);
state_ = State::STOPPING;
arc_session_->OnShutdown();
}
// ArcSession::OnShutdown() invokes OnSessionStopped() synchronously.
// In the observer method, |arc_session_| should be destroyed.
DCHECK(!arc_session_);
}
bool ArcSessionRunner::IsRunning() const {
DCHECK(thread_checker_.CalledOnValidThread());
return state_ == State::RUNNING;
}
bool ArcSessionRunner::IsStopped() const {
DCHECK(thread_checker_.CalledOnValidThread());
return state_ == State::STOPPED;
}
void ArcSessionRunner::SetRestartDelayForTesting(
const base::TimeDelta& restart_delay) {
DCHECK_EQ(state_, State::STOPPED);
DCHECK(!arc_session_);
DCHECK(!restart_timer_.IsRunning());
restart_delay_ = restart_delay;
}
void ArcSessionRunner::StartArcSession() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_EQ(state_, State::STOPPED);
DCHECK(!arc_session_);
DCHECK(!restart_timer_.IsRunning());
VLOG(1) << "Starting ARC instance";
arc_session_ = factory_.Run();
arc_session_->AddObserver(this);
state_ = State::STARTING;
arc_session_->Start();
}
void ArcSessionRunner::OnSessionReady() {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_EQ(state_, State::STARTING);
DCHECK(arc_session_);
DCHECK(!restart_timer_.IsRunning());
VLOG(0) << "ARC ready";
state_ = State::RUNNING;
}
void ArcSessionRunner::OnSessionStopped(ArcStopReason stop_reason) {
DCHECK(thread_checker_.CalledOnValidThread());
DCHECK_NE(state_, State::STOPPED);
DCHECK(arc_session_);
DCHECK(!restart_timer_.IsRunning());
VLOG(0) << "ARC stopped: " << stop_reason;
arc_session_->RemoveObserver(this);
arc_session_.reset();
// If RUNNING, ARC instance unexpectedly crashed so we need to restart it
// automatically.
// If STOPPING, at least once RequestStop() is called. If |session_started_|
// is true, RequestStart() is following so schedule to restart ARC session.
// Otherwise, do nothing.
// If STARTING, ARC instance has not been booted properly, so do not
// restart it automatically.
const bool restarting = (state_ == State::RUNNING ||
(state_ == State::STOPPING && run_requested_));
if (restarting) {
// This check is for RUNNING case. In RUNNING case |run_requested_| should
// be always true, because if once RequestStop() is called, the state_
// will be set to STOPPING.
DCHECK(run_requested_);
// There was a previous invocation and it crashed for some reason. Try
// starting ARC instance later again.
// Note that even |restart_delay_| is 0 (for testing), it needs to
// PostTask, because observer callback may call RequestStart()/Stop().
VLOG(0) << "ARC restarting";
restart_timer_.Start(FROM_HERE, restart_delay_,
base::Bind(&ArcSessionRunner::StartArcSession,
weak_ptr_factory_.GetWeakPtr()));
}
state_ = State::STOPPED;
for (auto& observer : observer_list_)
observer.OnSessionStopped(stop_reason, restarting);
}
} // namespace arc
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