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// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef DEVICE_UDEV_LINUX_UDEV_WATCHER_H_
#define DEVICE_UDEV_LINUX_UDEV_WATCHER_H_
#include <memory>
#include <optional>
#include <string>
#include <string_view>
#include <vector>
#include "base/component_export.h"
#include "base/files/file_descriptor_watcher_posix.h"
#include "base/memory/raw_ptr.h"
#include "base/sequence_checker.h"
#include "device/udev_linux/scoped_udev.h"
namespace device {
// This class wraps an instance of udev_monitor, watching for devices that are
// added and removed from the system. This class has sequence affinity.
class COMPONENT_EXPORT(DEVICE_UDEV_LINUX) UdevWatcher {
public:
class Observer {
public:
virtual void OnDeviceAdded(ScopedUdevDevicePtr device) = 0;
virtual void OnDeviceRemoved(ScopedUdevDevicePtr device) = 0;
virtual void OnDeviceChanged(ScopedUdevDevicePtr device) = 0;
protected:
virtual ~Observer();
};
// subsystem and devtype parameter for
// udev_monitor_filter_add_match_subsystem_devtype().
class Filter {
public:
Filter(std::string_view subsystem_in, std::string_view devtype_in);
Filter(const Filter&);
~Filter();
const char* devtype() const;
const char* subsystem() const;
private:
std::optional<std::string> subsystem_;
std::optional<std::string> devtype_;
};
static std::unique_ptr<UdevWatcher> StartWatching(
Observer* observer,
const std::vector<Filter>& filters = {});
UdevWatcher(const UdevWatcher&) = delete;
UdevWatcher& operator=(const UdevWatcher&) = delete;
~UdevWatcher();
// Synchronously enumerates the all devices known to udev, calling
// OnDeviceAdded on the provided Observer for each.
void EnumerateExistingDevices();
private:
UdevWatcher(ScopedUdevPtr udev,
ScopedUdevMonitorPtr udev_monitor,
int monitor_fd,
Observer* observer,
const std::vector<Filter>& filters);
void OnMonitorReadable();
ScopedUdevPtr udev_;
ScopedUdevMonitorPtr udev_monitor_;
raw_ptr<Observer> observer_;
const std::vector<Filter> udev_filters_;
std::unique_ptr<base::FileDescriptorWatcher::Controller> file_watcher_;
SEQUENCE_CHECKER(sequence_checker_);
};
} // namespace device
#endif // DEVICE_UDEV_LINUX_UDEV_WATCHER_H_
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