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- // Copyright (c) 2011 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 <stdint.h>
- #include "base/files/file_util.h"
- #include "base/files/memory_mapped_file.h"
- #include "base/logging.h"
- namespace base {
- 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_t length;
- if (!GetFileSize(file, &length)) {
- DLOG(ERROR) << "failed to get size of " << file.value();
- return false;
- }
- // When a file is empty, we do not need to evict it from cache.
- // In fact, an attempt to map it to memory will result in error.
- if (length == 0) {
- DLOG(WARNING) << "file size is zero, will not attempt to map to memory";
- return true;
- }
- MemoryMappedFile mapped_file;
- if (!mapped_file.Initialize(file)) {
- DLOG(WARNING) << "failed to memory map " << file.value();
- return false;
- }
- if (msync(const_cast<uint8_t*>(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 base
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