Fix AmountOfFreeDiskSpace to be able to differentiate an error...

base/sys_info_win.cc

 // Copyright (c) 2008 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 "base/sys_info.h"
 
 #include <windows.h>
 
 #include "base/logging.h"
 
 namespace base {
 
 // static
 int SysInfo::NumberOfProcessors() {
   SYSTEM_INFO info;
   GetSystemInfo(&info);
   return static_cast<int>(info.dwNumberOfProcessors);
 }
 
 // static
 int64 SysInfo::AmountOfPhysicalMemory() {
   MEMORYSTATUSEX memory_info;
   memory_info.dwLength = sizeof(memory_info);
   if (!GlobalMemoryStatusEx(&memory_info)) {
     NOTREACHED();
     return 0;
   }
 
-  return static_cast<int64>(memory_info.ullTotalPhys);
+  int64 rv = static_cast<int64>(memory_info.ullTotalPhys);
+  if (rv < 0)
+    rv = kint64max;
+  return rv;
 }
 
 // static
 int64 SysInfo::AmountOfFreeDiskSpace(const std::wstring& path) {
   ULARGE_INTEGER available, total, free;
   if (!GetDiskFreeSpaceExW(path.c_str(), &available, &total, &free)) {
-    return 0;
+    return -1;
   }
-  return static_cast<int64>(available.QuadPart);
+  int64 rv = static_cast<int64>(available.QuadPart);
+  if (rv < 0)
+    rv = kint64max;
+  return rv;
 }
 
 }  // namespace base