Reland: Add code to deal with serial device disconnection detection on Windows

device/core/device_info_query_win.h

+// Copyright 2015 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.
+
+#ifndef DEVICE_CORE_DEVICE_INFO_QUERY_WIN_H_
+#define DEVICE_CORE_DEVICE_INFO_QUERY_WIN_H_
+
+#include <windows.h>
+#include <setupapi.h>
+
+#include <string.h>
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/strings/string_util.h"
+
+namespace device {
+
+// Wrapper around a HDEVINFO and SP_DEVINFO_DATA that automatically destroys
+// them.
+class DeviceInfoQueryWin {
+ public:
+  DeviceInfoQueryWin()
+      : device_info_list_(SetupDiCreateDeviceInfoList(nullptr, nullptr)) {
+    memset(&device_info_data_, 0, sizeof(device_info_data_));
+  }
+
+  ~DeviceInfoQueryWin() {
+    if (device_info_list_ != INVALID_HANDLE_VALUE) {

[grt (UTC plus 2), 2015/11/16 21:41:56]

nit: if (device_info_list_valid()) {

[juncai, 2015/11/16 23:37:51]

Done.

+      if (device_info_data_.cbSize != 0)
+        SetupDiDeleteDeviceInfo(device_info_list_, &device_info_data_);
+      SetupDiDestroyDeviceInfoList(device_info_list_);
+    }
+  }
+
+  bool AddDevice(const char* device_path) {
+    return SetupDiOpenDeviceInterfaceA(device_info_list_, device_path, 0,
+                                       nullptr) != FALSE;
+  }
+
+  bool GetDeviceInfo() {
+    DCHECK_EQ(0U, device_info_data_.cbSize);
+    device_info_data_.cbSize = sizeof(device_info_data_);
+    if (!SetupDiEnumDeviceInfo(device_info_list_, 0, &device_info_data_)) {
+      device_info_data_.cbSize = 0;
+      return false;
+    }
+    return true;
+  }
+
+  bool GetDeviceStringProperty(DWORD property,
+                               PDWORD property_reg_data_type,

[grt (UTC plus 2), 2015/11/16 21:41:56]

the callers of this only care about REG_SZ. why not hide the type and do the
REG_SZ validation inside this function? make it as easy as possible to use.

[juncai, 2015/11/16 23:37:51]

Done.

+                               std::string* property_buffer) {
+    size_t property_buffer_length = 512;

[grt (UTC plus 2), 2015/11/16 21:41:56]

nit: const

[juncai, 2015/11/16 23:37:51]

Done.

+    return SetupDiGetDeviceRegistryPropertyA(
+               device_info_list_, &device_info_data_, property,
+               property_reg_data_type,
+               reinterpret_cast<PBYTE>(base::WriteInto(
+                   property_buffer, property_buffer_length + 1)),

[grt (UTC plus 2), 2015/11/16 21:41:56]

why add 1?

[juncai, 2015/11/16 23:37:51]

Done.

+               property_buffer_length, nullptr) != FALSE;

[grt (UTC plus 2), 2015/11/16 21:41:56]

the string in |property_buffer| isn't sized properly after this call succeeds
(std::string::size() will report 255). you should do something like this to
shrink it down before returning success so that callers get a proper string:

  size_t eos = property_buffer->find('\0');
  if (eos != std::string::npos)
    property_buffer->resize(eos);

[juncai, 2015/11/16 23:37:51]

Done.

+  }
+
+  bool device_info_list_valid() {
+    return device_info_list_ != INVALID_HANDLE_VALUE;
+  }
+
+  HDEVINFO device_info_list() { return device_info_list_; }
+
+  PSP_DEVINFO_DATA device_info_data() { return &device_info_data_; }
+
+ private:
+  HDEVINFO device_info_list_ = INVALID_HANDLE_VALUE;
+  SP_DEVINFO_DATA device_info_data_;

[grt (UTC plus 2), 2015/11/16 21:41:56]

nit: document the invariant that device_info_data_.cbSize != 0 when the data is
valid.

[juncai, 2015/11/16 23:37:51]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(DeviceInfoQueryWin);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_CORE_DEVICE_INFO_QUERY_WIN_H_