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/*
* Copyright (C) 2009 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef _UTILS_BACKUP_HELPERS_H
#define _UTILS_BACKUP_HELPERS_H
#include <utils/Errors.h>
#include <utils/String8.h>
namespace android {
enum {
BACKUP_HEADER_APP_V1 = 0x31707041, // App1 (little endian)
BACKUP_HEADER_ENTITY_V1 = 0x61746144, // Data (little endian)
BACKUP_FOOTER_APP_V1 = 0x746f6f46, // Foot (little endian)
};
// the sizes of all of these match.
typedef struct {
int type; // == BACKUP_HEADER_APP_V1
int packageLen; // length of the name of the package that follows, not including the null.
int cookie;
} app_header_v1;
typedef struct {
int type; // BACKUP_HEADER_ENTITY_V1
int keyLen; // length of the key name, not including the null terminator
int dataSize; // size of the data, not including the padding, -1 means delete
} entity_header_v1;
typedef struct {
int type; // BACKUP_FOOTER_APP_V1
int entityCount; // the number of entities that were written
int cookie;
} app_footer_v1;
/**
* Writes the data.
*
* If an error occurs, it poisons this object and all write calls will fail
* with the error that occurred.
*/
class BackupDataWriter
{
public:
BackupDataWriter(int fd);
// does not close fd
~BackupDataWriter();
status_t WriteAppHeader(const String8& packageName, int cookie);
status_t WriteEntityHeader(const String8& key, size_t dataSize);
status_t WriteEntityData(const void* data, size_t size);
status_t WriteAppFooter(int cookie);
private:
explicit BackupDataWriter();
status_t write_padding_for(int n);
int m_fd;
status_t m_status;
ssize_t m_pos;
int m_entityCount;
};
/**
* Reads the data.
*
* If an error occurs, it poisons this object and all write calls will fail
* with the error that occurred.
*/
class BackupDataReader
{
public:
BackupDataReader(int fd);
// does not close fd
~BackupDataReader();
status_t Status();
status_t ReadNextHeader(int* type = NULL);
status_t ReadAppHeader(String8* packageName, int* cookie);
bool HasEntities();
status_t ReadEntityHeader(String8* key, size_t* dataSize);
status_t SkipEntityData(); // must be called with the pointer at the begining of the data.
status_t ReadEntityData(void* data, size_t size);
status_t ReadAppFooter(int* cookie);
private:
explicit BackupDataReader();
status_t skip_padding();
int m_fd;
status_t m_status;
ssize_t m_pos;
int m_entityCount;
union {
int type;
app_header_v1 app;
entity_header_v1 entity;
app_footer_v1 footer;
} m_header;
};
int back_up_files(int oldSnapshotFD, BackupDataWriter* dataStream, int newSnapshotFD,
char const* fileBase, char const* const* files, int fileCount);
#define TEST_BACKUP_HELPERS 1
#if TEST_BACKUP_HELPERS
int backup_helper_test_empty();
int backup_helper_test_four();
int backup_helper_test_files();
int backup_helper_test_data_writer();
int backup_helper_test_data_reader();
#endif
} // namespace android
#endif // _UTILS_BACKUP_HELPERS_H
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