1 // Copyright 2014 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "net/disk_cache/simple/simple_util.h" 6 7 #include <windows.h> 8 9 #include "base/files/file_util.h" 10 #include "base/format_macros.h" 11 #include "base/rand_util.h" 12 #include "base/strings/string_util.h" 13 #include "base/strings/stringprintf.h" 14 #include "net/disk_cache/cache_util.h" 15 16 namespace disk_cache { 17 namespace simple_util { 18 SimpleCacheDeleteFile(const base::FilePath & path)19bool SimpleCacheDeleteFile(const base::FilePath& path) { 20 // Even if a file was opened with FLAG_WIN_SHARE_DELETE, it is not possible to 21 // create a new file with the same name until the original file is actually 22 // deleted. To allow new files to be created with the new name right away, 23 // the file is renamed before it is deleted. 24 25 // Why a random name? Because if the name was derived from our original name, 26 // then churn on a particular cache entry could cause flakey behaviour. 27 28 // TODO(morlovich): Ensure these "todelete_" files are cleaned up on periodic 29 // directory sweeps. 30 const base::FilePath rename_target = 31 path.DirName().AppendASCII(base::StringPrintf("todelete_%016" PRIx64, 32 base::RandUint64())); 33 34 bool rename_succeeded = 35 !!MoveFile(path.value().c_str(), rename_target.value().c_str()); 36 if (rename_succeeded) 37 return base::DeleteFile(rename_target); 38 39 // The rename did not succeed. The fallback behaviour is to delete the file in 40 // place, which might cause some flake. 41 return base::DeleteFile(path); 42 } 43 44 } // namespace simple_util 45 } // namespace disk_cache 46