HID backend

device/hid/hid_service_linux.cc

+// Copyright (c) 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 <libudev.h>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/logging.h"
+#include "base/memory/scoped_vector.h"
+#include "base/platform_file.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_piece.h"
+#include "base/strings/string_split.h"
+#include "base/threading/thread_restrictions.h"
+#include "device/hid/hid_connection.h"
+#include "device/hid/hid_connection_linux.h"
+#include "device/hid/hid_device_info.h"
+#include "device/hid/hid_service_linux.h"
+
+namespace device {
+
+namespace {
+
+const char* kUdevName = "udev";

[Ken Rockot(use gerrit already), 2014/01/21 23:03:39]

nit: Preference in Chrome code seems to be array form (i.e. const char kFoo[] =
...). I'm not sure if there is a good reason to prefer this, but there are
differences.

[Bei Zhang, 2014/01/24 12:48:47]

Yeah right... I think it's because this way you can get the size of the string
pretty easily. Nice catch.

Done.

On 2014/01/21 23:03:39, Ken Rockot wrote:

+const char* kUdevActionAdd = "add";
+const char* kUdevActionRemove = "remove";
+const char* kHIDSubSystem = "hid";
+
+const char* kHIDID = "HID_ID";
+const char* kHIDName = "HID_NAME";
+const char* kHIDUnique = "HID_UNIQ";
+
+} // namespace
+
+HidServiceLinux::HidServiceLinux() {
+  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_filter_add_match_subsystem_devtype(
+      monitor_.get(),
+      kHIDSubSystem,
+      NULL);
+  if (ret != 0) {
+    LOG(ERROR) << "Failed to add udev monitor filter.";
+    return;
+  }
+
+  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;
+
+  Enumerate();
+}
+
+HidServiceLinux::~HidServiceLinux() {
+  monitor_watcher_.StopWatchingFileDescriptor();
+  close(monitor_fd_);
+}
+
+void HidServiceLinux::Enumerate() {
+  scoped_ptr<udev_enumerate, UdevEnumerateDeleter> enumerate(
+      udev_enumerate_new(udev_.get()));
+
+  if (!enumerate) {
+    LOG(ERROR) << "Failed to enumerate devices.";
+    return;
+  }
+
+  if (udev_enumerate_add_match_subsystem(enumerate.get(), kHIDSubSystem)) {
+    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 hid_dev(
+        udev_device_new_from_syspath(udev_.get(), udev_list_entry_get_name(i)));
+    if (hid_dev) {
+      PlatformDeviceAdd(hid_dev.get());
+    }
+  }
+
+  initialized_ = true;
+}
+
+void HidServiceLinux::PlatformDeviceAdd(udev_device* device) {
+  if (!device)
+    return;
+
+  const char* device_id = udev_device_get_syspath(device);
+  if (!device_id)
+    return;
+
+
+  HidDeviceInfo device_info;
+  device_info.device_id = device_id;
+
+  uint32 int_property = 0;
+  const char* str_property = NULL;
+
+  const char* hid_id = udev_device_get_property_value(device, kHIDID);
+  if (!hid_id)
+    return;
+
+  std::vector<std::string> parts;
+  base::SplitString(hid_id, ':', &parts);
+  if (parts.size() != 3) {
+    return;
+  }
+
+  if (HexStringToUInt(base::StringPiece(parts[1]), &int_property)) {
+    device_info.vendor_id = int_property;
+  }
+
+  if (HexStringToUInt(base::StringPiece(parts[2]), &int_property)) {
+    device_info.product_id = int_property;
+  }
+
+  str_property = udev_device_get_property_value(device, kHIDUnique);
+  if (str_property != NULL)
+    device_info.serial_number = str_property;
+
+  str_property = udev_device_get_property_value(device, kHIDName);
+  if (str_property != NULL)
+    device_info.product_name = str_property;
+
+  DeviceAdd(device_info);
+}
+
+void HidServiceLinux::PlatformDeviceRemove(udev_device* raw_dev) {
+  // The returned the device is not referenced.
+  udev_device* hid_dev =
+      udev_device_get_parent_with_subsystem_devtype(raw_dev, "hid", NULL);
+
+  if (!hid_dev)
+    return;
+
+  const char* device_id = NULL;
+  device_id = udev_device_get_syspath(hid_dev);
+  if (device_id == NULL)
+    return;
+
+  DeviceRemove(device_id);
+}
+
+scoped_refptr<HidConnection> HidServiceLinux::Connect(std::string device_id) {
+  if (!ContainsKey(devices_, device_id))
+    return NULL;
+  ScopedUdevDevicePtr hid_device(
+      udev_device_new_from_syspath(udev_.get(), device_id.c_str()));
+  if (hid_device) {
+    scoped_refptr<HidConnectionLinux> connection =
+        new HidConnectionLinux(devices_[device_id], hid_device.Pass());
+    if (connection->initialized())
+      return connection;
+  }
+  return NULL;
+}
+
+void HidServiceLinux::OnFileCanReadWithoutBlocking(int fd) {
+  DCHECK_EQ(monitor_fd_, fd);
+
+  ScopedUdevDevicePtr dev(udev_monitor_receive_device(monitor_.get()));
+  if (!dev)
+    return;
+
+  std::string action(udev_device_get_action(dev.get()));
+  if (action == kUdevActionAdd) {
+    PlatformDeviceAdd(dev.get());
+  } else if (action == kUdevActionRemove) {
+    PlatformDeviceRemove(dev.get());
+  }
+}
+void HidServiceLinux::OnFileCanWriteWithoutBlocking(int fd) {}
+

[Ken Rockot(use gerrit already), 2014/01/21 23:03:39]

TODO, at least? Or do you intend to implement in this CL?

[Bei Zhang, 2014/01/24 12:48:47]

Done.

+} // namespace dev