Return true when file size is zero.

base/test/test_file_util_mac.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/test/test_file_util.h"
 
 #include <sys/mman.h>
 #include <errno.h>
 #include "base/logging.h"
 #include "base/file_util.h"
 
 namespace file_util {
 
 bool EvictFileFromSystemCache(const FilePath& file) {
   // There aren't any really direct ways to purge a file from the UBC.  From
   // talking with Amit Singh, the safest is to mmap the file with MAP_FILE (the
   // default) + MAP_SHARED, then do an msync to invalidate the memory.  The next
   // open should then have to load the file from disk.
 
+  int64 length;

[kkania, 2011/07/22 23:48:58]

add a comment why this is needed

[Huyen, 2011/07/23 00:00:36]

Done.

+  file_util::GetFileSize(file, &length);

[kkania, 2011/07/22 23:48:58]

This could fail. log a warning and return false.

[Huyen, 2011/07/23 00:00:36]

Done.

+  if (length == 0) {

[kkania, 2011/07/22 23:48:58]

if (!length)
  return true;

[Huyen, 2011/07/23 00:00:36]

Done.

+    return true;
+  }
+
   file_util::MemoryMappedFile mapped_file;
   if (!mapped_file.Initialize(file)) {
     DLOG(WARNING) << "failed to memory map " << file.value();
     return false;
   }
 
   if (msync(const_cast<uint8*>(mapped_file.data()), mapped_file.length(),
             MS_INVALIDATE) != 0) {
     DLOG(WARNING) << "failed to invalidate memory map of " << file.value()
         << ", errno: " << errno;
     return false;
   }
 
   return true;
 }
 
 }  // namespace file_util