Refactor Udev device support in Ozone and add a DRM hotplug monitor

ui/events/ozone/evdev/device_manager_udev.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 "ui/events/ozone/evdev/device_manager_udev.h"
-
-#include <libudev.h>
-
-#include "base/debug/trace_event.h"
-#include "base/files/file_path.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/strings/string_util.h"
-#include "base/strings/stringprintf.h"
-#include "ui/events/ozone/evdev/device_manager_evdev.h"
-#include "ui/events/ozone/evdev/event_factory_evdev.h"
-#include "ui/events/ozone/evdev/scoped_udev.h"
-
-namespace ui {
-
-namespace {
-
-const char kSubsystemInput[] = "input";
-
-// Severity levels from syslog.h. We can't include it directly as it
-// conflicts with base/logging.h
-enum {
-  SYS_LOG_EMERG = 0,
-  SYS_LOG_ALERT = 1,
-  SYS_LOG_CRIT = 2,
-  SYS_LOG_ERR = 3,
-  SYS_LOG_WARNING = 4,
-  SYS_LOG_NOTICE = 5,
-  SYS_LOG_INFO = 6,
-  SYS_LOG_DEBUG = 7,
-};
-
-// Log handler for messages generated from libudev.
-void UdevLog(struct udev* udev,
-             int priority,
-             const char* file,
-             int line,
-             const char* fn,
-             const char* format,
-             va_list args) {
-  if (priority <= SYS_LOG_ERR)
-    LOG(ERROR) << "libudev: " << fn << ": " << base::StringPrintV(format, args);
-  else if (priority <= SYS_LOG_INFO)
-    VLOG(1) << "libudev: " << fn << ": " << base::StringPrintV(format, args);
-  else  // SYS_LOG_DEBUG
-    VLOG(2) << "libudev: " << fn << ": " << base::StringPrintV(format, args);
-}
-
-// Create libudev context.
-scoped_udev UdevCreate() {
-  struct udev* udev = udev_new();
-  if (udev) {
-    udev_set_log_fn(udev, UdevLog);
-    udev_set_log_priority(udev, SYS_LOG_DEBUG);
-  }
-  return scoped_udev(udev);
-}
-
-// Start monitoring input device changes.
-scoped_udev_monitor UdevCreateMonitor(struct udev* udev) {
-  struct udev_monitor* monitor = udev_monitor_new_from_netlink(udev, "udev");
-  if (monitor) {
-    udev_monitor_filter_add_match_subsystem_devtype(
-        monitor, kSubsystemInput, NULL);
-
-    if (udev_monitor_enable_receiving(monitor))
-      LOG(ERROR) << "failed to start receiving events from udev";
-  }
-
-  return scoped_udev_monitor(monitor);
-}
-
-// Enumerate all input devices using udev. Calls device_callback per device.
-bool UdevEnumerateInputDevices(struct udev* udev,
-                               const EvdevDeviceCallback& device_callback) {
-  scoped_udev_enumerate enumerate(udev_enumerate_new(udev));
-  if (!enumerate)
-    return false;
-
-  // Build list of devices with subsystem "input".
-  udev_enumerate_add_match_subsystem(enumerate.get(), kSubsystemInput);
-  udev_enumerate_scan_devices(enumerate.get());
-
-  struct udev_list_entry* devices =
-      udev_enumerate_get_list_entry(enumerate.get());
-  struct udev_list_entry* entry;
-
-  // Run callback per device in the list.
-  udev_list_entry_foreach(entry, devices) {
-    const char* name = udev_list_entry_get_name(entry);
-
-    scoped_udev_device device(udev_device_new_from_syspath(udev, name));
-    if (!device)
-      continue;
-
-    const char* path = udev_device_get_devnode(device.get());
-    if (!path)
-      continue;
-
-    // Filter non-evdev device notes.
-    if (!StartsWithASCII(path, "/dev/input/event", true))
-      continue;
-
-    // Found input device node; attach.
-    device_callback.Run(base::FilePath(path));
-  }
-
-  return true;
-}
-
-// Device enumerator & monitor using udev.
-//
-// This class enumerates input devices attached to the system using udev.
-//
-// It also creates & monitors a udev netlink socket and issues callbacks for
-// any changes to the set of attached devices.
-//
-// TODO(spang): Figure out how to test this.
-class DeviceManagerUdev : public DeviceManagerEvdev,
-                          base::MessagePumpLibevent::Watcher {
- public:
-  DeviceManagerUdev() {}
-  virtual ~DeviceManagerUdev() { Stop(); }
-
-  // Enumerate existing devices & start watching for device changes.
-  virtual void ScanAndStartMonitoring(const EvdevDeviceCallback& device_added,
-                                      const EvdevDeviceCallback& device_removed)
-      OVERRIDE {
-    udev_ = UdevCreate();
-    if (!udev_) {
-      LOG(ERROR) << "failed to initialize libudev";
-      return;
-    }
-
-    if (!StartMonitoring(device_added, device_removed))
-      LOG(ERROR) << "failed to start monitoring device changes via udev";
-
-    if (!UdevEnumerateInputDevices(udev_.get(), device_added))
-      LOG(ERROR) << "failed to enumerate input devices via udev";
-  }
-
-  virtual void Stop() OVERRIDE {
-    controller_.StopWatchingFileDescriptor();
-    device_added_.Reset();
-    device_removed_.Reset();
-  }
-
-  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE {
-    // The netlink socket should never become disconnected. There's no need
-    // to handle broken connections here.
-    TRACE_EVENT1("ozone", "UdevDeviceChange", "socket", fd);
-
-    scoped_udev_device device(udev_monitor_receive_device(udev_monitor_.get()));
-    if (!device)
-      return;
-
-    const char* path = udev_device_get_devnode(device.get());
-    const char* action = udev_device_get_action(device.get());
-    if (!path || !action)
-      return;
-
-    if (!strcmp(action, "add") || !strcmp(action, "change"))
-      device_added_.Run(base::FilePath(path));
-    else if (!strcmp(action, "remove"))
-      device_removed_.Run(base::FilePath(path));
-  }
-
-  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE { NOTREACHED(); }
-
- private:
-  bool StartMonitoring(const EvdevDeviceCallback& device_added,
-                       const EvdevDeviceCallback& device_removed) {
-    udev_monitor_ = UdevCreateMonitor(udev_.get());
-    if (!udev_monitor_)
-      return false;
-
-    // Grab monitor socket.
-    int fd = udev_monitor_get_fd(udev_monitor_.get());
-    if (fd < 0)
-      return false;
-
-    // Save callbacks.
-    device_added_ = device_added;
-    device_removed_ = device_removed;
-
-    // Watch for incoming events on monitor socket.
-    return base::MessageLoopForUI::current()->WatchFileDescriptor(
-        fd, true, base::MessagePumpLibevent::WATCH_READ, &controller_, this);
-  }
-
-  // Udev daemon connection.
-  scoped_udev udev_;
-
-  // Udev device change monitor.
-  scoped_udev_monitor udev_monitor_;
-
-  // Callbacks for device changes.
-  EvdevDeviceCallback device_added_;
-  EvdevDeviceCallback device_removed_;
-
-  // Watcher for uevent netlink socket.
-  base::MessagePumpLibevent::FileDescriptorWatcher controller_;
-
-  DISALLOW_COPY_AND_ASSIGN(DeviceManagerUdev);
-};
-
-}  // namespace
-
-scoped_ptr<DeviceManagerEvdev> CreateDeviceManagerUdev() {
-  return make_scoped_ptr<DeviceManagerEvdev>(new DeviceManagerUdev());
-}
-
-}  // namespace ui