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/*
Copyright (C) 2019-2024 Selwin van Dijk
This file is part of signalbackup-tools.
signalbackup-tools is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
signalbackup-tools is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with signalbackup-tools. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef MEMFILEDB_H_
#define MEMFILEDB_H_
#include <sqlite3.h>
#include <utility>
#include <cstdint>
#include <cstring>
#include <memory>
class MemFileDB
{
struct MemFile
{
sqlite3_file base; // Base class. Must be first.
unsigned char *data;
uint64_t datasize;
};
static sqlite3_vfs s_memfilevfs;
static char constexpr s_name[] = {'M', 'e', 'm', 'f', 'i', 'l', 'e', 'V', 'F', 'S', '\0'};
public:
static sqlite3_vfs *sqlite3_memfilevfs(std::pair<unsigned char *, uint64_t> *data);
static char const *vfsName()
{
return s_name;
}
private:
static int ioWrite(sqlite3_file *, void const *, int, sqlite_int64);
static int ioClose(sqlite3_file *pFile);
static int ioRead(sqlite3_file *pFile, void *zBuf, int iAmt, sqlite_int64 iOfst);
static int ioTruncate(sqlite3_file *pFile, sqlite_int64 size);
static int ioSync(sqlite3_file *pFile, int flags);
static int ioFileSize(sqlite3_file *pFile, sqlite_int64 *pSize);
static int ioLock(sqlite3_file *pFile, int eLock);
static int ioUnlock(sqlite3_file *pFile, int eLock);
static int ioCheckReservedLock(sqlite3_file *pFile, int *pResOut);
static int ioFileControl(sqlite3_file *pFile, int op, void *pArg);
static int ioSectorSize(sqlite3_file *pFile);
static int ioDeviceCharacteristics(sqlite3_file *pFile);
static int open(sqlite3_vfs *pVfs, char const *zName, sqlite3_file *pFile, int flags, int *pOutFlags);
static int del(sqlite3_vfs *pVfs, char const *zPath, int dirSync);
static int access(sqlite3_vfs *pVfs, char const *zPath, int flags, int *pResOut);
static int fullPathname(sqlite3_vfs *pVfs, char const *zPath, int nPathOut, char *zPathOut);
static sqlite3_io_methods constexpr s_io = {1, /* iVersion */
MemFileDB::ioClose, /* xClose */
MemFileDB::ioRead, /* xRead */
MemFileDB::ioWrite, /* xWrite */
MemFileDB::ioTruncate, /* xTruncate */
MemFileDB::ioSync, /* xSync */
MemFileDB::ioFileSize, /* xFileSize */
MemFileDB::ioLock, /* xLock */
MemFileDB::ioUnlock, /* xUnlock */
MemFileDB::ioCheckReservedLock, /* xCheckReservedLock */
MemFileDB::ioFileControl, /* xFileControl */
MemFileDB::ioSectorSize, /* xSectorSize */
MemFileDB::ioDeviceCharacteristics, /* xDeviceCharacteristics */
/* since we specified iversion == 1 above, the next fields actually
should not exist, but just to suppress gcc warnings.... */
nullptr, /* xShmMap */
nullptr, /* xShmLock */
nullptr, /* xShmBarrier */
nullptr, /* xShmUnmap */
nullptr, /* xFetch */
nullptr, /* xUnfetch */};
};
inline int MemFileDB::ioClose(sqlite3_file *pFile [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return SQLITE_OK;
}
inline int MemFileDB::ioRead(sqlite3_file *pFile, void *zBuf, int iAmt, sqlite_int64 iOfst)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
if (static_cast<uint64_t>(iOfst) >= reinterpret_cast<MemFile *>(pFile)->datasize ||
!reinterpret_cast<MemFile *>(pFile)->data)
{
//std::cout << " !!! ERROR_READ !!!" << std::endl;
return SQLITE_IOERR_READ;
}
int toread = iAmt;
bool shortread = false;
if (static_cast<uint64_t>(iOfst + iAmt) > reinterpret_cast<MemFile *>(pFile)->datasize)
{
//std::cout << "SHORTREAD" << std::endl;
toread -= ((iOfst + iAmt) - reinterpret_cast<MemFile *>(pFile)->datasize);
shortread = true;
}
std::memcpy(zBuf, reinterpret_cast<MemFile *>(pFile)->data + iOfst, toread);
if (shortread)
return SQLITE_IOERR_SHORT_READ;
return SQLITE_OK;
}
inline int MemFileDB::ioWrite(sqlite3_file *pFile [[maybe_unused]], void const *, int, sqlite_int64)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
//std::cout << " !!! ERROR_WRITE !!!" << std::endl;
return SQLITE_READONLY;
}
inline int MemFileDB::ioTruncate(sqlite3_file *pFile [[maybe_unused]], sqlite_int64 size [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
//std::cout << " !!! ERROR_TRUNC !!!" << std::endl;
return SQLITE_IOERR_TRUNCATE;
}
inline int MemFileDB::ioSync(sqlite3_file *pFile [[maybe_unused]], int flags [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
//return SQLITE_OK; // read only, there's never anything to sync
return SQLITE_IOERR_FSYNC;
}
inline int MemFileDB::ioFileSize(sqlite3_file *pFile, sqlite_int64 *pSize)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
*pSize = reinterpret_cast<MemFile *>(pFile)->datasize;
return SQLITE_OK;
}
inline int MemFileDB::ioLock(sqlite3_file *pFile [[maybe_unused]], int eLock [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return SQLITE_OK;
}
inline int MemFileDB::ioUnlock(sqlite3_file *pFile [[maybe_unused]], int eLock [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return SQLITE_OK;
}
inline int MemFileDB::ioCheckReservedLock(sqlite3_file *pFile [[maybe_unused]], int *pResOut)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
*pResOut = 0;
return SQLITE_OK;
}
inline int MemFileDB::ioFileControl(sqlite3_file *pFile [[maybe_unused]], int op [[maybe_unused]], void *pArg [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return SQLITE_NOTFOUND;
}
inline int MemFileDB::ioSectorSize(sqlite3_file *pFile [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return 0;
}
inline int MemFileDB::ioDeviceCharacteristics(sqlite3_file *pFile [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
return 0;
}
inline int MemFileDB::fullPathname(sqlite3_vfs *pVfs [[maybe_unused]], /* VFS */
char const *zPath [[maybe_unused]], /* Input path (possibly a relative path) */
int nPathOut [[maybe_unused]], /* Size of output buffer in bytes */
char *zPathOut) /* Pointer to output buffer */
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
if (nPathOut >= static_cast<int>(strlen(zPath)))
{
std::strcpy(zPathOut, zPath);
return SQLITE_OK;
}
else
return SQLITE_CANTOPEN;
}
inline int MemFileDB::open(sqlite3_vfs *pVfs, /* VFS */
char const *zName [[maybe_unused]], /* File to open, or 0 for a temp file */
sqlite3_file *pFile, /* Pointer to DemoFile struct to populate */
int flags [[maybe_unused]], /* Input SQLITE_OPEN_XXX flags */
int *pOutFlags) /* Output SQLITE_OPEN_XXX flags (or NULL) */
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
MemFile *p = reinterpret_cast<MemFile *>(pFile); /* Populate this structure */
std::memset(p, 0, sizeof(MemFile));
if (pOutFlags)
*pOutFlags = flags | SQLITE_READONLY | SQLITE_OPEN_MEMORY;
p->base.pMethods = &s_io;
p->data = reinterpret_cast<std::pair<unsigned char *, uint64_t> const *>(pVfs->pAppData)->first;
p->datasize = reinterpret_cast<std::pair<unsigned char *, uint64_t> const *>(pVfs->pAppData)->second;
return SQLITE_OK;
}
inline int MemFileDB::del(sqlite3_vfs *pVfs [[maybe_unused]], const char *zPath [[maybe_unused]], int dirSync [[maybe_unused]])
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
//return SQLITE_OK;
//std::cout << " !!! ERROR_DEL !!!" << std::endl;
return SQLITE_IOERR_DELETE;
}
inline int MemFileDB::access(sqlite3_vfs *pVfs, char const *zPath [[maybe_unused]], int flags [[maybe_unused]], int *pResOut)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
if (reinterpret_cast<std::pair<unsigned char *, uint64_t> const *>(pVfs->pAppData)->first &&
reinterpret_cast<std::pair<unsigned char *, uint64_t> const *>(pVfs->pAppData)->second > 0)
{
*pResOut = 0;
return SQLITE_OK;
}
//std::cout << " !!! ERROR_ACCESS !!! " << std::endl;
return SQLITE_IOERR_ACCESS;
}
inline sqlite3_vfs *MemFileDB::sqlite3_memfilevfs(std::pair<unsigned char *, uint64_t> *data)
{
//std::cout << "Called: " << __FUNCTION__ << std::endl;
std::memset(&s_memfilevfs, 0, sizeof(s_memfilevfs));
s_memfilevfs = {1, /* iVersion */
sizeof(MemFile), /* szOsFile */
sizeof(s_name) + 8, /* mxPathname // needs enough room for 'path' (I set it to filename used in
sqlite3_open() call in fullPathname()) + 8 for '-journal'
(and other) suffix added by sqlite*/
0, /* pNext */
vfsName(), /* zName */
data, /* pAppData */
open, /* xOpen */
del, /* xDelete */
access, /* xAccess */
fullPathname, /* xFullPathname */
nullptr, /* xDlOpen */
nullptr, /* xDlError */
nullptr, /* xDlSym */
nullptr, /* xDlClose */
nullptr, /* xRandomness */
nullptr, /* xSleep */
nullptr, /* xCurrentTime */
nullptr, /* xGetLastError */
/* since we specified iversion == 1 above, the next fields actually
should not exist, but just to suppress gcc warnings.... */
nullptr, /* xCurrentTimeInt64 */
nullptr, /* xSetSystemCall */
nullptr, /* xGetSystemCall */
nullptr, /* xNextSystemCall */
};
return &s_memfilevfs;
}
#endif
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