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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 "webkit/fileapi/file_system_usage_cache.h"
#include "base/file_path.h"
#include "base/file_util.h"
#include "base/pickle.h"
namespace fileapi {
const char FileSystemUsageCache::kUsageFileName[] = ".usage";
const char FileSystemUsageCache::kUsageFileHeader[] = "FSU0";
const int FileSystemUsageCache::kUsageFileHeaderSize = 4;
const int FileSystemUsageCache::kUsageFileSize =
sizeof(Pickle::Header) +
FileSystemUsageCache::kUsageFileHeaderSize +
sizeof(int32) + sizeof(int64);
// static
int64 FileSystemUsageCache::GetUsage(const FilePath& usage_file_path) {
uint32 dirty = 0;
int64 fs_usage;
fs_usage = Read(usage_file_path, &dirty);
if (fs_usage < 0 || dirty > 0)
return -1;
return fs_usage;
}
// static
bool FileSystemUsageCache::IncrementDirty(const FilePath& usage_file_path) {
uint32 dirty = 0;
int64 fs_usage;
fs_usage = Read(usage_file_path, &dirty);
if (fs_usage < 0)
return false;
return Write(usage_file_path, dirty + 1, fs_usage) >= 0;
}
// static
bool FileSystemUsageCache::DecrementDirty(const FilePath& usage_file_path) {
uint32 dirty = 0;
int64 fs_usage;
fs_usage = Read(usage_file_path, &dirty);
if (fs_usage < 0 || dirty <= 0)
return false;
return Write(usage_file_path, dirty - 1, fs_usage) >= 0;
}
// static
int FileSystemUsageCache::UpdateUsage(const FilePath& usage_file_path,
int64 fs_usage) {
return Write(usage_file_path, 0, fs_usage);
}
// static
bool FileSystemUsageCache::Exists(const FilePath& usage_file_path) {
return file_util::PathExists(usage_file_path);
}
// static
bool FileSystemUsageCache::Delete(const FilePath& usage_file_path) {
return file_util::Delete(usage_file_path, true);
}
// static
int64 FileSystemUsageCache::Read(const FilePath& usage_file_path,
uint32* dirty) {
char buffer[kUsageFileSize];
const char *header;
if (kUsageFileSize !=
file_util::ReadFile(usage_file_path, buffer, kUsageFileSize))
return -1;
Pickle read_pickle(buffer, kUsageFileSize);
void* iter = NULL;
int64 fs_usage;
if (!read_pickle.ReadBytes(&iter, &header, kUsageFileHeaderSize) ||
!read_pickle.ReadUInt32(&iter, dirty) ||
!read_pickle.ReadInt64(&iter, &fs_usage))
return -1;
if (header[0] != kUsageFileHeader[0] ||
header[1] != kUsageFileHeader[1] ||
header[2] != kUsageFileHeader[2] ||
header[3] != kUsageFileHeader[3])
return -1;
return fs_usage;
}
// static
int FileSystemUsageCache::Write(const FilePath& usage_file_path,
uint32 dirty, int64 fs_usage) {
Pickle write_pickle;
write_pickle.WriteBytes(kUsageFileHeader, kUsageFileHeaderSize);
write_pickle.WriteUInt32(dirty);
write_pickle.WriteInt64(fs_usage);
FilePath temporary_usage_file_path;
file_util::CreateTemporaryFileInDir(usage_file_path.DirName(),
&temporary_usage_file_path);
int bytes_written = file_util::WriteFile(temporary_usage_file_path,
(const char *)write_pickle.data(),
write_pickle.size());
if (bytes_written != kUsageFileSize)
return -1;
if (file_util::ReplaceFile(temporary_usage_file_path, usage_file_path))
return bytes_written;
else
return -1;
}
}
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