metrics/base: log whether drives have seek penalties.

base/sys_info_win.cc

Index: base/sys_info_win.cc
diff --git a/base/sys_info_win.cc b/base/sys_info_win.cc
index 9cc0cfa48a3637d48c36978de2c798383e9a194d..a65ea6895575bc4175fa496ce1af163848a3617b 100644
--- a/base/sys_info_win.cc
+++ b/base/sys_info_win.cc
@@ -5,7 +5,9 @@
 #include "base/sys_info.h"
 
 #include <windows.h>
+#include <winioctl.h>
 
+#include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
@@ -24,9 +26,7 @@ int64 AmountOfMemory(DWORDLONG MEMORYSTATUSEX::* memory_field) {
   }
 
   int64 rv = static_cast<int64>(memory_info.*memory_field);
-  if (rv < 0)
-    rv = kint64max;
-  return rv;
+  return rv < 0 ? kint64max : rv;
 }
 
 }  // namespace
@@ -55,16 +55,46 @@ int64 SysInfo::AmountOfVirtualMemory() {
 
 // static
 int64 SysInfo::AmountOfFreeDiskSpace(const FilePath& path) {
-  base::ThreadRestrictions::AssertIOAllowed();
+  ThreadRestrictions::AssertIOAllowed();
 
   ULARGE_INTEGER available, total, free;
-  if (!GetDiskFreeSpaceExW(path.value().c_str(), &available, &total, &free)) {
+  if (!GetDiskFreeSpaceExW(path.value().c_str(), &available, &total, &free))
     return -1;
-  }
+
   int64 rv = static_cast<int64>(available.QuadPart);
-  if (rv < 0)
-    rv = kint64max;
-  return rv;
+  return rv < 0 ? kint64max : rv;
+}
+
+bool SysInfo::HasSeekPenalty(const FilePath& path, bool* has_seek_penalty) {
+  ThreadRestrictions::AssertIOAllowed();
+
+  DCHECK(has_seek_penalty);
+
+  // TODO(dbeam): Vista, XP support.
+  if (!path.IsAbsolute() || win::GetVersion() < win::VERSION_WIN7)

[rvargas (doing something else), 2015/03/13 21:03:09]

I have not heard why allowing callers to use relative paths is a good thing :)

[Dan Beam, 2015/03/13 21:15:51]

Done. (changed to DCHECK)

+    return false;
+
+  std::vector<FilePath::StringType> components;
+  native_path.GetComponents(&components);
+  File drive(FilePath(L"\\\\.\\" + components[0]), File::FLAG_OPEN);

[rvargas (doing something else), 2015/03/13 21:03:09]

Still requires if (!drive.IsValid())...

[Dan Beam, 2015/03/13 21:15:51]

Done.

+
+  STORAGE_PROPERTY_QUERY query;
+  query.QueryType = PropertyStandardQuery;
+  query.PropertyId = StorageDeviceSeekPenaltyProperty;
+
+  DEVICE_SEEK_PENALTY_DESCRIPTOR result;
+
+  success = DeviceIoControl(drive.GetPlatformFile(),
+                            IOCTL_STORAGE_QUERY_PROPERTY,
+                            &query, sizeof(query),
+                            &result, sizeof(result),
+                            &bytes_returned,

[rvargas (doing something else), 2015/03/13 21:03:09]

not defined?

[Dan Beam, 2015/03/13 21:15:51]

whoops, Done.

+                            NULL);
+  if (success == FALSE || bytes_returned < sizeof(result))
+    return false;
+
+  *has_seek_penalty = result.IncursSeekPenalty == TRUE;

[rvargas (doing something else), 2015/03/13 21:03:09]

Comparing against TRUE is not a good idea (in general) because TRUE == 1 and
some functions can return another value even though it is supposed to be a bool.

[Dan Beam, 2015/03/13 21:15:51]

Done.

+  return true;
 }
 
 // static