net: FileStream cleanup

base/files/file_win.cc

 // 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 "base/files/file.h"
 
 #include <io.h>
 
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
 
+// Make sure our Whence mappings match the system headers.
+COMPILE_ASSERT(File::FROM_BEGIN   == FILE_BEGIN &&
+               File::FROM_CURRENT == FILE_CURRENT &&
+               File::FROM_END     == FILE_END, whence_matches_system);
+
 void File::InitializeUnsafe(const FilePath& name, uint32 flags) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(!IsValid());
 
   DWORD disposition = 0;
 
   if (flags & FLAG_OPEN)
     disposition = OPEN_EXISTING;
 
   if (flags & FLAG_CREATE) {
@@ skipping 85 matching lines @@
 void File::Close() {
   if (file_.IsValid()) {
     base::ThreadRestrictions::AssertIOAllowed();
     file_.Close();
   }
 }
 
 int64 File::Seek(Whence whence, int64 offset) {
   base::ThreadRestrictions::AssertIOAllowed();
   DCHECK(IsValid());
-  if (offset < 0)
-    return -1;
 
   LARGE_INTEGER distance, res;
   distance.QuadPart = offset;
   DWORD move_method = static_cast<DWORD>(whence);
   if (!SetFilePointerEx(file_, distance, &res, move_method))
     return -1;
   return res.QuadPart;
 }
 
 int File::Read(int64 offset, char* data, int size) {
@@ skipping 206 matching lines @@
                                   last_error);
       return FILE_ERROR_FAILED;
   }
 }
 
 void File::SetPlatformFile(PlatformFile file) {
   file_.Set(file);
 }
 
 }  // namespace base