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// Copyright 2015 The Chromium OS 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 LIBBRILLO_BRILLO_MESSAGE_LOOPS_BASE_MESSAGE_LOOP_H_
#define LIBBRILLO_BRILLO_MESSAGE_LOOPS_BASE_MESSAGE_LOOP_H_
// BaseMessageLoop is a brillo::MessageLoop implementation based on
// base::MessageLoopForIO. This allows to mix new code using
// brillo::MessageLoop and legacy code using base::MessageLoopForIO in the
// same thread and share a single main loop. This disadvantage of using this
// class is a less efficient implementation of CancelTask() for delayed tasks
// since base::MessageLoopForIO doesn't provide a way to remove the event.
#include <map>
#include <memory>
#include <string>
#include <base/files/file_descriptor_watcher_posix.h>
#include <base/location.h>
#include <base/memory/weak_ptr.h>
#include <base/message_loop/message_loop.h>
#include <base/message_loop/message_pump_for_io.h>
#include <base/time/time.h>
#include <gtest/gtest_prod.h>
#include <brillo/brillo_export.h>
#include <brillo/message_loops/message_loop.h>
namespace brillo {
class BRILLO_EXPORT BaseMessageLoop : public MessageLoop {
public:
// Construct a base::MessageLoopForIO message loop instance and use it as
// the default message loop for this thread.
BaseMessageLoop();
// Construct a brillo::BaseMessageLoop using the passed base::MessageLoopForIO
// instance.
explicit BaseMessageLoop(base::MessageLoopForIO* base_loop);
~BaseMessageLoop() override;
// MessageLoop overrides.
TaskId PostDelayedTask(const base::Location& from_here,
const base::Closure& task,
base::TimeDelta delay) override;
using MessageLoop::PostDelayedTask;
bool CancelTask(TaskId task_id) override;
bool RunOnce(bool may_block) override;
void Run() override;
void BreakLoop() override;
// Returns a callback that will quit the current message loop. If the message
// loop is not running, an empty (null) callback is returned.
base::Closure QuitClosure() const;
private:
FRIEND_TEST(BaseMessageLoopTest, ParseBinderMinor);
static const int kInvalidMinor;
static const int kUninitializedMinor;
// Parses the contents of the file /proc/misc passed in |file_contents| and
// returns the minor device number reported for binder. On error or if not
// found, returns kInvalidMinor.
static int ParseBinderMinor(const std::string& file_contents);
// Called by base::MessageLoopForIO when is time to call the callback
// scheduled with Post*Task() of id |task_id|, even if it was canceled.
void OnRanPostedTask(MessageLoop::TaskId task_id);
// Return a new unused task_id.
TaskId NextTaskId();
// Returns binder minor device number.
unsigned int GetBinderMinor();
struct DelayedTask {
base::Location location;
MessageLoop::TaskId task_id;
base::Closure closure;
};
// The base::MessageLoopForIO instance owned by this class, if any. This
// is declared first in this class so it is destroyed last.
std::unique_ptr<base::MessageLoopForIO> owned_base_loop_;
// Tasks blocked on a timeout.
std::map<MessageLoop::TaskId, DelayedTask> delayed_tasks_;
// Flag to mark that we should run the message loop only one iteration.
bool run_once_{false};
// The last used TaskId. While base::MessageLoopForIO doesn't allow to cancel
// delayed tasks, we handle that functionality by not running the callback
// if it fires at a later point.
MessageLoop::TaskId last_id_{kTaskIdNull};
// The pointer to the libchrome base::MessageLoopForIO we are wrapping with
// this interface. If the instance was created from this object, this will
// point to that instance.
base::MessageLoopForIO* base_loop_;
// FileDescriptorWatcher for |base_loop_|. This is used in AlarmTimer.
std::unique_ptr<base::FileDescriptorWatcher> watcher_;
// The RunLoop instance used to run the main loop from Run().
base::RunLoop* base_run_loop_{nullptr};
// The binder minor device number. Binder is a "misc" char device with a
// dynamically allocated minor number. When uninitialized, this value will
// be negative, otherwise, it will hold the minor part of the binder device
// number. This is populated by GetBinderMinor().
int binder_minor_{kUninitializedMinor};
// We use a WeakPtrFactory to schedule tasks with the base::MessageLoopForIO
// since we can't cancel the callbacks we have scheduled there once this
// instance is destroyed.
base::WeakPtrFactory<BaseMessageLoop> weak_ptr_factory_{this};
DISALLOW_COPY_AND_ASSIGN(BaseMessageLoop);
};
} // namespace brillo
#endif // LIBBRILLO_BRILLO_MESSAGE_LOOPS_BASE_MESSAGE_LOOP_H_
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