Udev-related methods are extracted from HidServiceLinux into individual service.

device/hid/device_monitor_linux.cc

+// Copyright 2014 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 "device/hid/device_monitor_linux.h"
+
+#include <libudev.h>
+
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+
+namespace device {
+
+namespace {
+
+const char kUdevName[] = "udev";
+const char kUdevActionAdd[] = "add";
+const char kUdevActionRemove[] = "remove";
+
+// The instance will be reset when message loop destroys.
+base::LazyInstance<scoped_ptr<DeviceMonitorLinux> >::Leaky
+    g_device_monitor_linux_ptr = LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+DeviceMonitorLinux::DeviceMonitorLinux() : monitor_fd_(-1) {
+  udev_.reset(udev_new());
+  if (!udev_) {
+    LOG(ERROR) << "Failed to create udev.";
+    return;
+  }
+  monitor_.reset(udev_monitor_new_from_netlink(udev_.get(), kUdevName));
+  if (!monitor_) {
+    LOG(ERROR) << "Failed to create udev monitor.";
+    return;
+  }
+
+  int ret = udev_monitor_enable_receiving(monitor_.get());
+  if (ret != 0) {
+    LOG(ERROR) << "Failed to start udev monitoring.";
+    return;
+  }
+
+  monitor_fd_ = udev_monitor_get_fd(monitor_.get());
+  if (monitor_fd_ <= 0) {
+    LOG(ERROR) << "Failed to start udev monitoring.";
+    return;
+  }
+
+  if (!base::MessageLoopForIO::current()->WatchFileDescriptor(
+          monitor_fd_,
+          true,
+          base::MessageLoopForIO::WATCH_READ,
+          &monitor_watcher_,
+          this)) {
+    return;
+  }
+}
+
+DeviceMonitorLinux::~DeviceMonitorLinux() {
+  monitor_watcher_.StopWatchingFileDescriptor();
+  close(monitor_fd_);
+}
+
+// static
+DeviceMonitorLinux* DeviceMonitorLinux::GetInstance() {
+  if (!HasInstance())
+    g_device_monitor_linux_ptr.Get().reset(new DeviceMonitorLinux());
+  return g_device_monitor_linux_ptr.Get().get();
+}
+
+// static
+bool DeviceMonitorLinux::HasInstance() {
+  return g_device_monitor_linux_ptr.Get().get();
+}
+
+void DeviceMonitorLinux::AddObserver(Observer* observer) {
+  if (observer)
+    observers_.AddObserver(observer);
+}
+
+void DeviceMonitorLinux::RemoveObserver(Observer* observer) {
+  if (observer)
+    observers_.RemoveObserver(observer);
+}
+
+ScopedUdevDevicePtr DeviceMonitorLinux::GetDeviceFromPath(
+    const std::string& path) {
+  ScopedUdevDevicePtr device(
+      udev_device_new_from_syspath(udev_.get(), path.c_str()));
+  return device.Pass();
+}
+
+void DeviceMonitorLinux::Enumerate(const EnumerateCallback& callback) {
+  ScopedUdevEnumeratePtr enumerate(udev_enumerate_new(udev_.get()));
+
+  if (!enumerate) {
+    LOG(ERROR) << "Failed to enumerate devices.";
+    return;
+  }
+
+  if (udev_enumerate_scan_devices(enumerate.get()) != 0) {
+    LOG(ERROR) << "Failed to enumerate devices.";
+    return;
+  }
+
+  // This list is managed by |enumerate|.
+  udev_list_entry* devices = udev_enumerate_get_list_entry(enumerate.get());
+  for (udev_list_entry* i = devices; i != NULL;
+       i = udev_list_entry_get_next(i)) {
+    ScopedUdevDevicePtr device(
+        udev_device_new_from_syspath(udev_.get(), udev_list_entry_get_name(i)));
+    if (device)
+      callback.Run(device.get());
+  }
+}
+
+void DeviceMonitorLinux::OnFileCanReadWithoutBlocking(int fd) {
+  DCHECK_EQ(monitor_fd_, fd);
+
+  ScopedUdevDevicePtr device(udev_monitor_receive_device(monitor_.get()));
+  if (!device)
+    return;
+
+  std::string action(udev_device_get_action(device.get()));
+  if (action == kUdevActionAdd)
+    FOR_EACH_OBSERVER(Observer, observers_, OnDeviceAdded(device.get()));
+  else if (action == kUdevActionRemove)
+    FOR_EACH_OBSERVER(Observer, observers_, OnDeviceRemoved(device.get()));
+}
+
+void DeviceMonitorLinux::OnFileCanWriteWithoutBlocking(int fd) {}
+
+}  // namespace device