Add systeminfo.storage API implementation skeleton

chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc

Index: chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
diff --git a/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..524ba82556b7b1cf929ded342598f660f07e5c89
--- /dev/null
+++ b/chrome/browser/extensions/api/system_info_storage/storage_info_provider_win.cc
@@ -0,0 +1,94 @@
+// Copyright (c) 2012 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 "chrome/browser/extensions/api/system_info_storage/storage_info_provider.h"
+
+#include "base/string_util.h"
+
+#include <windows.h>
+
+namespace extensions {
+
+using api::experimental_system_info_storage::StorageInfo;
+using api::experimental_system_info_storage::StorageUnitInfo;
+
+// Logical drive string length is 4. It contains one driver letter character,
+// L":", L"\" and a terminating null character.
+const unsigned long kMaxLogicalDriveString = 4 * 26;
+
+// StorageInfoProvider implementation on Windows platform.
+class StorageInfoProviderWin : public StorageInfoProvider {
+ public:
+  StorageInfoProviderWin();
+  virtual ~StorageInfoProviderWin();
+
+  virtual bool GetStorageInfo(StorageInfo* info) OVERRIDE;
+};
+
+// static
+StorageInfoProvider* StorageInfoProvider::Create() {
+  return new StorageInfoProviderWin();
+}
+
+// StorageInfoProviderWin implementation.
+StorageInfoProviderWin::StorageInfoProviderWin() {
+}
+
+StorageInfoProviderWin::~StorageInfoProviderWin() {
+}
+
+bool StorageInfoProviderWin::GetStorageInfo(StorageInfo* info) {
+  if (info == NULL) return false;
+
+  WCHAR logical_drive_strings[kMaxLogicalDriveString];
+
+  // The total length of drive string returned from GetLogicalDriveStrings
+  // must be divided exactly by 4 since each drive is represented by 4 wchars.
+  DWORD string_length = GetLogicalDriveStrings(
+      kMaxLogicalDriveString - 1, logical_drive_strings);
+  DCHECK(string_length % 4 == 0);
+  // No drive found, return false.
+  if (string_length == 0)
+    return false;
+
+  // Iterate the drive string by 4 wchars each step
+  for (unsigned int i = 0; i < string_length; i += 4) {
+    std::string type;
+    DWORD ret = GetDriveType(&logical_drive_strings[i]);
+    switch (ret) {
+      case DRIVE_FIXED:
+        type = systeminfo::kStorageTypeHardDisk;
+        break;
+      case DRIVE_REMOVABLE:
+        type = systeminfo::kStorageTypeRemovable;
+        break;
+      case DRIVE_UNKNOWN:
+        type = systeminfo::kStorageTypeUnknown;
+        break;
+      case DRIVE_CDROM:       // CD ROM
+      case DRIVE_REMOTE:      // Remote network drive
+      case DRIVE_NO_ROOT_DIR: // Invalid root path
+      case DRIVE_RAMDISK:     // RAM disk
+        // TODO(hmin): Do we need to care about these drive types?
+        continue;
+    }
+
+    ULARGE_INTEGER available_bytes;
+    ULARGE_INTEGER free_bytes;
+    BOOL status = GetDiskFreeSpaceEx(&logical_drive_strings[i], NULL,
+                                     &available_bytes,
+                                     &free_bytes);
+    if (status) {
+      linked_ptr<StorageUnitInfo> unit(new StorageUnitInfo());
+      unit->id = WideToASCII(string16(&logical_drive_strings[i]));
+      unit->type = type;
+      unit->capacity = static_cast<double>(available_bytes.QuadPart);
+      unit->available_capacity = static_cast<double>(free_bytes.QuadPart);
+      info->units.push_back(unit);
+    }
+  }
+  return true;
+}
+
+}  // namespace extensions