Extracts more information from serial devices on Windows

device/serial/serial_device_enumerator_win.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/serial/serial_device_enumerator_win.h"
 
 #include <windows.h>
 
+#include <ntddser.h>
+#include <setupapi.h>
+
 #include "base/memory/scoped_ptr.h"
-#include "base/strings/string_util.h"
-#include "base/strings/stringprintf.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
-#include "base/win/registry.h"
+#include "third_party/re2/re2/re2.h"
 
 namespace device {
 
+namespace {
+
+// Searches the specified device info for a property with the specified key,
+// assigns the result to value, and returns whether the operation was
+// successful.
+bool GetProperty(HDEVINFO dev_info,
+                 SP_DEVINFO_DATA dev_info_data,
+                 const int key,
+                 std::string* value) {
+  // We don't know how much space the property's value will take up, so we call
+  // the property retrieval function once to fetch the size of the required
+  // value buffer, then again once we've allocated a sufficiently large buffer.
+  DWORD buffer_size = 0;
+  SetupDiGetDeviceRegistryProperty(dev_info, &dev_info_data, key, nullptr,
+                                   nullptr, buffer_size, &buffer_size);
+  if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
+    return false;
+
+  scoped_ptr<wchar_t[]> buffer(new wchar_t[buffer_size]);
+  if (!SetupDiGetDeviceRegistryProperty(dev_info, &dev_info_data, key, nullptr,
+                                        reinterpret_cast<PBYTE>(buffer.get()),
+                                        buffer_size, nullptr))
+    return false;
+
+  *value = base::WideToUTF8(buffer.get());
+  return true;
+}
+
+// Searches for the COM port in the device's friendly name, assigns its value to
+// com_port, and returns whether the operation was successful.
+bool GetCOMPort(const std::string friendly_name, std::string* com_port) {
+  return RE2::PartialMatch(friendly_name, ".* \\((COM[0-9]+)\\)", com_port);
+}
+
+// Searches for the display name in the device's friendly name, assigns its
+// value to display_name, and returns whether the operation was successful.
+bool GetDisplayName(const std::string friendly_name,
+                    std::string* display_name) {
+  return RE2::PartialMatch(friendly_name, "(.*) \\(COM[0-9]+\\)", display_name);
+}
+
+// Searches for the vendor ID in the device's hardware ID, assigns its value to
+// vendor_id, and returns whether the operation was successful.
+bool GetVendorID(const std::string hardware_id, uint32_t* vendor_id) {
+  std::string vendor_id_str;
+  return RE2::PartialMatch(hardware_id, "VID_([0-9]+)", &vendor_id_str) &&
+         base::HexStringToUInt(vendor_id_str, vendor_id);
+}
+
+// Searches for the product ID in the device's product ID, assigns its value to
+// product_id, and returns whether the operation was successful.
+bool GetProductID(const std::string hardware_id, uint32_t* product_id) {
+  std::string product_id_str;
+  return RE2::PartialMatch(hardware_id, "PID_([0-9]+)", &product_id_str) &&
+         base::HexStringToUInt(product_id_str, product_id);
+}
+
+}  // namespace
+
 // static
 scoped_ptr<SerialDeviceEnumerator> SerialDeviceEnumerator::Create() {
   return scoped_ptr<SerialDeviceEnumerator>(new SerialDeviceEnumeratorWin());
 }
 
 SerialDeviceEnumeratorWin::SerialDeviceEnumeratorWin() {}
 
 SerialDeviceEnumeratorWin::~SerialDeviceEnumeratorWin() {}
 
-// TODO(rockot): Query the system for more information than just device paths.
-// This may or may not require using a different strategy than scanning the
-// registry location below.
 mojo::Array<serial::DeviceInfoPtr> SerialDeviceEnumeratorWin::GetDevices() {
-  base::win::RegistryValueIterator iter_key(
-      HKEY_LOCAL_MACHINE, L"HARDWARE\\DEVICEMAP\\SERIALCOMM\\");
   mojo::Array<serial::DeviceInfoPtr> devices(0);
-  for (; iter_key.Valid(); ++iter_key) {
+
+  // Make a device interface query to find all serial devices.
+  HDEVINFO dev_info =
+      SetupDiGetClassDevs(&GUID_DEVINTERFACE_SERENUM_BUS_ENUMERATOR, 0, 0,
+                          DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
+  if (dev_info == INVALID_HANDLE_VALUE)
+    return devices.Pass();
+
+  SP_DEVINFO_DATA dev_info_data;
+  dev_info_data.cbSize = sizeof(SP_DEVINFO_DATA);
+  for (DWORD i = 0; SetupDiEnumDeviceInfo(dev_info, i, &dev_info_data); i++) {
+    std::string friendly_name, com_port;
+    // SPDRP_FRIENDLYNAME looks like "USB_SERIAL_PORT (COM3)".
+    if (!GetProperty(dev_info, dev_info_data, SPDRP_FRIENDLYNAME,
+                     &friendly_name) ||
+        !GetCOMPort(friendly_name, &com_port))
+      // In Windows, the COM port is the path used to uniquely identify the
+      // serial device. If the COM can't be found, ignore the device.
+      continue;
+
     serial::DeviceInfoPtr info(serial::DeviceInfo::New());
-    info->path = base::UTF16ToASCII(iter_key.Value());
+    info->path = com_port;
+
+    std::string display_name;
+    if (GetDisplayName(friendly_name, &display_name))
+      info->display_name = display_name;
+
+    std::string hardware_id;
+    // SPDRP_HARDWAREID looks like "FTDIBUS\COMPORT&VID_0403&PID_6001".
+    if (GetProperty(dev_info, dev_info_data, SPDRP_HARDWAREID, &hardware_id)) {
+      uint32_t vendor_id, product_id;
+      if (GetVendorID(hardware_id, &vendor_id)) {
+        info->has_vendor_id = true;
+        info->vendor_id = vendor_id;
+      }
+      if (GetProductID(hardware_id, &product_id)) {
+        info->has_product_id = true;
+        info->product_id = product_id;
+      }
+    }
+
     devices.push_back(info.Pass());
   }
+
+  SetupDiDestroyDeviceInfoList(dev_info);
   return devices.Pass();
 }
 
 }  // namespace device