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sqlcipher/src/test_onefile.c

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/*
** 2007 September 14
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
**
** OVERVIEW:
**
** This file contains some example code demonstrating how the SQLite
** vfs feature can be used to have SQLite operate directly on an
** embedded media, without using an intermediate file system.
**
** Because this is only a demo designed to run on a workstation, the
** underlying media is simulated using a regular file-system file. The
** size of the file is fixed when it is first created (default size 10 MB).
** From SQLite's point of view, this space is used to store a single
** database file and the journal file.
**
** Any statement journal created is stored in volatile memory obtained
** from sqlite3_malloc(). Any attempt to create a temporary database file
** will fail (SQLITE_IOERR). To prevent SQLite from attempting this,
** it should be configured to store all temporary database files in
** main memory (see pragma "temp_store" or the SQLITE_TEMP_STORE compile
** time option).
**
** ASSUMPTIONS:
**
** After it has been created, the blob file is accessed using the
** following three functions only:
**
** mediaRead(); - Read a 512 byte block from the file.
** mediaWrite(); - Write a 512 byte block to the file.
** mediaSync(); - Tell the media hardware to sync.
**
** It is assumed that these can be easily implemented by any "real"
** media vfs driver adapting this code.
**
** FILE FORMAT:
**
** The basic principle is that the "database file" is stored at the
** beginning of the 10 MB blob and grows in a forward direction. The
** "journal file" is stored at the end of the 10MB blob and grows
** in the reverse direction. If, during a transaction, insufficient
** space is available to expand either the journal or database file,
** an SQLITE_FULL error is returned. The database file is never allowed
** to consume more than 90% of the blob space. If SQLite tries to
** create a file larger than this, SQLITE_FULL is returned.
**
** No allowance is made for "wear-leveling", as is required by.
** embedded devices in the absence of equivalent hardware features.
**
** The first 512 block byte of the file is reserved for storing the
** size of the "database file". It is updated as part of the sync()
** operation. On startup, it can only be trusted if no journal file
** exists. If a journal-file does exist, then it stores the real size
** of the database region. The second and subsequent blocks store the
** actual database content.
**
** The size of the "journal file" is not stored persistently in the
** file. When the system is running, the size of the journal file is
** stored in volatile memory. When recovering from a crash, this vfs
** reports a very large size for the journal file. The normal journal
** header and checksum mechanisms serve to prevent SQLite from
** processing any data that lies past the logical end of the journal.
**
** When SQLite calls OsDelete() to delete the journal file, the final
** 512 bytes of the blob (the area containing the first journal header)
** are zeroed.
**
** LOCKING:
**
** File locking is a no-op. Only one connection may be open at any one
** time using this demo vfs.
*/
#include "sqlite3.h"
#include <assert.h>
#include <string.h>
/*
** Maximum pathname length supported by the fs backend.
*/
#define BLOCKSIZE 512
#define BLOBSIZE 10485760
/*
** Name used to identify this VFS.
*/
#define FS_VFS_NAME "fs"
typedef struct fs_real_file fs_real_file;
struct fs_real_file {
sqlite3_file *pFile;
const char *zName;
int nDatabase; /* Current size of database region */
int nJournal; /* Current size of journal region */
int nBlob; /* Total size of allocated blob */
int nRef; /* Number of pointers to this structure */
fs_real_file *pNext;
fs_real_file **ppThis;
};
typedef struct fs_file fs_file;
struct fs_file {
sqlite3_file base;
int eType;
fs_real_file *pReal;
};
typedef struct tmp_file tmp_file;
struct tmp_file {
sqlite3_file base;
int nSize;
int nAlloc;
char *zAlloc;
};
/* Values for fs_file.eType. */
#define DATABASE_FILE 1
#define JOURNAL_FILE 2
/*
** Method declarations for fs_file.
*/
static int fsClose(sqlite3_file*);
static int fsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int fsWrite(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
static int fsTruncate(sqlite3_file*, sqlite3_int64 size);
static int fsSync(sqlite3_file*, int flags);
static int fsFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int fsLock(sqlite3_file*, int);
static int fsUnlock(sqlite3_file*, int);
static int fsCheckReservedLock(sqlite3_file*, int *pResOut);
static int fsFileControl(sqlite3_file*, int op, void *pArg);
static int fsSectorSize(sqlite3_file*);
static int fsDeviceCharacteristics(sqlite3_file*);
/*
** Method declarations for tmp_file.
*/
static int tmpClose(sqlite3_file*);
static int tmpRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int tmpWrite(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
static int tmpTruncate(sqlite3_file*, sqlite3_int64 size);
static int tmpSync(sqlite3_file*, int flags);
static int tmpFileSize(sqlite3_file*, sqlite3_int64 *pSize);
static int tmpLock(sqlite3_file*, int);
static int tmpUnlock(sqlite3_file*, int);
static int tmpCheckReservedLock(sqlite3_file*, int *pResOut);
static int tmpFileControl(sqlite3_file*, int op, void *pArg);
static int tmpSectorSize(sqlite3_file*);
static int tmpDeviceCharacteristics(sqlite3_file*);
/*
** Method declarations for fs_vfs.
*/
static int fsOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
static int fsDelete(sqlite3_vfs*, const char *zName, int syncDir);
static int fsAccess(sqlite3_vfs*, const char *zName, int flags, int *);
static int fsFullPathname(sqlite3_vfs*, const char *zName, int nOut,char *zOut);
static void *fsDlOpen(sqlite3_vfs*, const char *zFilename);
static void fsDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
static void (*fsDlSym(sqlite3_vfs*,void*, const char *zSymbol))(void);
static void fsDlClose(sqlite3_vfs*, void*);
static int fsRandomness(sqlite3_vfs*, int nByte, char *zOut);
static int fsSleep(sqlite3_vfs*, int microseconds);
static int fsCurrentTime(sqlite3_vfs*, double*);
typedef struct fs_vfs_t fs_vfs_t;
struct fs_vfs_t {
sqlite3_vfs base;
fs_real_file *pFileList;
sqlite3_vfs *pParent;
};
static fs_vfs_t fs_vfs = {
{
1, /* iVersion */
0, /* szOsFile */
0, /* mxPathname */
0, /* pNext */
FS_VFS_NAME, /* zName */
0, /* pAppData */
fsOpen, /* xOpen */
fsDelete, /* xDelete */
fsAccess, /* xAccess */
fsFullPathname, /* xFullPathname */
fsDlOpen, /* xDlOpen */
fsDlError, /* xDlError */
fsDlSym, /* xDlSym */
fsDlClose, /* xDlClose */
fsRandomness, /* xRandomness */
fsSleep, /* xSleep */
fsCurrentTime, /* xCurrentTime */
0 /* xCurrentTimeInt64 */
},
0, /* pFileList */
0 /* pParent */
};
static sqlite3_io_methods fs_io_methods = {
1, /* iVersion */
fsClose, /* xClose */
fsRead, /* xRead */
fsWrite, /* xWrite */
fsTruncate, /* xTruncate */
fsSync, /* xSync */
fsFileSize, /* xFileSize */
fsLock, /* xLock */
fsUnlock, /* xUnlock */
fsCheckReservedLock, /* xCheckReservedLock */
fsFileControl, /* xFileControl */
fsSectorSize, /* xSectorSize */
fsDeviceCharacteristics, /* xDeviceCharacteristics */
0, /* xShmMap */
0, /* xShmLock */
0, /* xShmBarrier */
0 /* xShmUnmap */
};
static sqlite3_io_methods tmp_io_methods = {
1, /* iVersion */
tmpClose, /* xClose */
tmpRead, /* xRead */
tmpWrite, /* xWrite */
tmpTruncate, /* xTruncate */
tmpSync, /* xSync */
tmpFileSize, /* xFileSize */
tmpLock, /* xLock */
tmpUnlock, /* xUnlock */
tmpCheckReservedLock, /* xCheckReservedLock */
tmpFileControl, /* xFileControl */
tmpSectorSize, /* xSectorSize */
tmpDeviceCharacteristics, /* xDeviceCharacteristics */
0, /* xShmMap */
0, /* xShmLock */
0, /* xShmBarrier */
0 /* xShmUnmap */
};
/* Useful macros used in several places */
#define MIN(x,y) ((x)<(y)?(x):(y))
#define MAX(x,y) ((x)>(y)?(x):(y))
/*
** Close a tmp-file.
*/
static int tmpClose(sqlite3_file *pFile){
tmp_file *pTmp = (tmp_file *)pFile;
sqlite3_free(pTmp->zAlloc);
return SQLITE_OK;
}
/*
** Read data from a tmp-file.
*/
static int tmpRead(
sqlite3_file *pFile,
void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
tmp_file *pTmp = (tmp_file *)pFile;
if( (iAmt+iOfst)>pTmp->nSize ){
return SQLITE_IOERR_SHORT_READ;
}
memcpy(zBuf, &pTmp->zAlloc[iOfst], iAmt);
return SQLITE_OK;
}
/*
** Write data to a tmp-file.
*/
static int tmpWrite(
sqlite3_file *pFile,
const void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
tmp_file *pTmp = (tmp_file *)pFile;
if( (iAmt+iOfst)>pTmp->nAlloc ){
int nNew = (int)(2*(iAmt+iOfst+pTmp->nAlloc));
char *zNew = sqlite3_realloc(pTmp->zAlloc, nNew);
if( !zNew ){
return SQLITE_NOMEM;
}
pTmp->zAlloc = zNew;
pTmp->nAlloc = nNew;
}
memcpy(&pTmp->zAlloc[iOfst], zBuf, iAmt);
pTmp->nSize = (int)MAX(pTmp->nSize, iOfst+iAmt);
return SQLITE_OK;
}
/*
** Truncate a tmp-file.
*/
static int tmpTruncate(sqlite3_file *pFile, sqlite_int64 size){
tmp_file *pTmp = (tmp_file *)pFile;
pTmp->nSize = (int)MIN(pTmp->nSize, size);
return SQLITE_OK;
}
/*
** Sync a tmp-file.
*/
static int tmpSync(sqlite3_file *pFile, int flags){
return SQLITE_OK;
}
/*
** Return the current file-size of a tmp-file.
*/
static int tmpFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
tmp_file *pTmp = (tmp_file *)pFile;
*pSize = pTmp->nSize;
return SQLITE_OK;
}
/*
** Lock a tmp-file.
*/
static int tmpLock(sqlite3_file *pFile, int eLock){
return SQLITE_OK;
}
/*
** Unlock a tmp-file.
*/
static int tmpUnlock(sqlite3_file *pFile, int eLock){
return SQLITE_OK;
}
/*
** Check if another file-handle holds a RESERVED lock on a tmp-file.
*/
static int tmpCheckReservedLock(sqlite3_file *pFile, int *pResOut){
*pResOut = 0;
return SQLITE_OK;
}
/*
** File control method. For custom operations on a tmp-file.
*/
static int tmpFileControl(sqlite3_file *pFile, int op, void *pArg){
return SQLITE_OK;
}
/*
** Return the sector-size in bytes for a tmp-file.
*/
static int tmpSectorSize(sqlite3_file *pFile){
return 0;
}
/*
** Return the device characteristic flags supported by a tmp-file.
*/
static int tmpDeviceCharacteristics(sqlite3_file *pFile){
return 0;
}
/*
** Close an fs-file.
*/
static int fsClose(sqlite3_file *pFile){
int rc = SQLITE_OK;
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
/* Decrement the real_file ref-count. */
pReal->nRef--;
assert(pReal->nRef>=0);
/* When the ref-count reaches 0, destroy the structure */
if( pReal->nRef==0 ){
*pReal->ppThis = pReal->pNext;
if( pReal->pNext ){
pReal->pNext->ppThis = pReal->ppThis;
}
rc = pReal->pFile->pMethods->xClose(pReal->pFile);
sqlite3_free(pReal);
}
return rc;
}
/*
** Read data from an fs-file.
*/
static int fsRead(
sqlite3_file *pFile,
void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
int rc = SQLITE_OK;
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
sqlite3_file *pF = pReal->pFile;
if( (p->eType==DATABASE_FILE && (iAmt+iOfst)>pReal->nDatabase)
|| (p->eType==JOURNAL_FILE && (iAmt+iOfst)>pReal->nJournal)
){
rc = SQLITE_IOERR_SHORT_READ;
}else if( p->eType==DATABASE_FILE ){
rc = pF->pMethods->xRead(pF, zBuf, iAmt, iOfst+BLOCKSIZE);
}else{
/* Journal file. */
int iRem = iAmt;
int iBuf = 0;
int ii = (int)iOfst;
while( iRem>0 && rc==SQLITE_OK ){
int iRealOff = pReal->nBlob - BLOCKSIZE*((ii/BLOCKSIZE)+1) + ii%BLOCKSIZE;
int iRealAmt = MIN(iRem, BLOCKSIZE - (iRealOff%BLOCKSIZE));
rc = pF->pMethods->xRead(pF, &((char *)zBuf)[iBuf], iRealAmt, iRealOff);
ii += iRealAmt;
iBuf += iRealAmt;
iRem -= iRealAmt;
}
}
return rc;
}
/*
** Write data to an fs-file.
*/
static int fsWrite(
sqlite3_file *pFile,
const void *zBuf,
int iAmt,
sqlite_int64 iOfst
){
int rc = SQLITE_OK;
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
sqlite3_file *pF = pReal->pFile;
if( p->eType==DATABASE_FILE ){
if( (iAmt+iOfst+BLOCKSIZE)>(pReal->nBlob-pReal->nJournal) ){
rc = SQLITE_FULL;
}else{
rc = pF->pMethods->xWrite(pF, zBuf, iAmt, iOfst+BLOCKSIZE);
if( rc==SQLITE_OK ){
pReal->nDatabase = (int)MAX(pReal->nDatabase, iAmt+iOfst);
}
}
}else{
/* Journal file. */
int iRem = iAmt;
int iBuf = 0;
int ii = (int)iOfst;
while( iRem>0 && rc==SQLITE_OK ){
int iRealOff = pReal->nBlob - BLOCKSIZE*((ii/BLOCKSIZE)+1) + ii%BLOCKSIZE;
int iRealAmt = MIN(iRem, BLOCKSIZE - (iRealOff%BLOCKSIZE));
if( iRealOff<(pReal->nDatabase+BLOCKSIZE) ){
rc = SQLITE_FULL;
}else{
rc = pF->pMethods->xWrite(pF, &((char *)zBuf)[iBuf], iRealAmt,iRealOff);
ii += iRealAmt;
iBuf += iRealAmt;
iRem -= iRealAmt;
}
}
if( rc==SQLITE_OK ){
pReal->nJournal = (int)MAX(pReal->nJournal, iAmt+iOfst);
}
}
return rc;
}
/*
** Truncate an fs-file.
*/
static int fsTruncate(sqlite3_file *pFile, sqlite_int64 size){
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
if( p->eType==DATABASE_FILE ){
pReal->nDatabase = (int)MIN(pReal->nDatabase, size);
}else{
pReal->nJournal = (int)MIN(pReal->nJournal, size);
}
return SQLITE_OK;
}
/*
** Sync an fs-file.
*/
static int fsSync(sqlite3_file *pFile, int flags){
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
sqlite3_file *pRealFile = pReal->pFile;
int rc = SQLITE_OK;
if( p->eType==DATABASE_FILE ){
unsigned char zSize[4];
zSize[0] = (pReal->nDatabase&0xFF000000)>>24;
zSize[1] = (unsigned char)((pReal->nDatabase&0x00FF0000)>>16);
zSize[2] = (pReal->nDatabase&0x0000FF00)>>8;
zSize[3] = (pReal->nDatabase&0x000000FF);
rc = pRealFile->pMethods->xWrite(pRealFile, zSize, 4, 0);
}
if( rc==SQLITE_OK ){
rc = pRealFile->pMethods->xSync(pRealFile, flags&(~SQLITE_SYNC_DATAONLY));
}
return rc;
}
/*
** Return the current file-size of an fs-file.
*/
static int fsFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = p->pReal;
if( p->eType==DATABASE_FILE ){
*pSize = pReal->nDatabase;
}else{
*pSize = pReal->nJournal;
}
return SQLITE_OK;
}
/*
** Lock an fs-file.
*/
static int fsLock(sqlite3_file *pFile, int eLock){
return SQLITE_OK;
}
/*
** Unlock an fs-file.
*/
static int fsUnlock(sqlite3_file *pFile, int eLock){
return SQLITE_OK;
}
/*
** Check if another file-handle holds a RESERVED lock on an fs-file.
*/
static int fsCheckReservedLock(sqlite3_file *pFile, int *pResOut){
*pResOut = 0;
return SQLITE_OK;
}
/*
** File control method. For custom operations on an fs-file.
*/
static int fsFileControl(sqlite3_file *pFile, int op, void *pArg){
if( op==SQLITE_FCNTL_PRAGMA ) return SQLITE_NOTFOUND;
return SQLITE_OK;
}
/*
** Return the sector-size in bytes for an fs-file.
*/
static int fsSectorSize(sqlite3_file *pFile){
return BLOCKSIZE;
}
/*
** Return the device characteristic flags supported by an fs-file.
*/
static int fsDeviceCharacteristics(sqlite3_file *pFile){
return 0;
}
/*
** Open an fs file handle.
*/
static int fsOpen(
sqlite3_vfs *pVfs,
const char *zName,
sqlite3_file *pFile,
int flags,
int *pOutFlags
){
fs_vfs_t *pFsVfs = (fs_vfs_t *)pVfs;
fs_file *p = (fs_file *)pFile;
fs_real_file *pReal = 0;
int eType;
int nName;
int rc = SQLITE_OK;
if( 0==(flags&(SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_MAIN_JOURNAL)) ){
tmp_file *p2 = (tmp_file *)pFile;
memset(p2, 0, sizeof(*p2));
p2->base.pMethods = &tmp_io_methods;
return SQLITE_OK;
}
eType = ((flags&(SQLITE_OPEN_MAIN_DB))?DATABASE_FILE:JOURNAL_FILE);
p->base.pMethods = &fs_io_methods;
p->eType = eType;
assert(strlen("-journal")==8);
nName = (int)strlen(zName)-((eType==JOURNAL_FILE)?8:0);
pReal=pFsVfs->pFileList;
for(; pReal && strncmp(pReal->zName, zName, nName); pReal=pReal->pNext);
if( !pReal ){
int real_flags = (flags&~(SQLITE_OPEN_MAIN_DB))|SQLITE_OPEN_TEMP_DB;
sqlite3_int64 size;
sqlite3_file *pRealFile;
sqlite3_vfs *pParent = pFsVfs->pParent;
assert(eType==DATABASE_FILE);
pReal = (fs_real_file *)sqlite3_malloc(sizeof(*pReal)+pParent->szOsFile);
if( !pReal ){
rc = SQLITE_NOMEM;
goto open_out;
}
memset(pReal, 0, sizeof(*pReal)+pParent->szOsFile);
pReal->zName = zName;
pReal->pFile = (sqlite3_file *)(&pReal[1]);
rc = pParent->xOpen(pParent, zName, pReal->pFile, real_flags, pOutFlags);
if( rc!=SQLITE_OK ){
goto open_out;
}
pRealFile = pReal->pFile;
rc = pRealFile->pMethods->xFileSize(pRealFile, &size);
if( rc!=SQLITE_OK ){
goto open_out;
}
if( size==0 ){
rc = pRealFile->pMethods->xWrite(pRealFile, "\0", 1, BLOBSIZE-1);
pReal->nBlob = BLOBSIZE;
}else{
unsigned char zS[4];
pReal->nBlob = (int)size;
rc = pRealFile->pMethods->xRead(pRealFile, zS, 4, 0);
pReal->nDatabase = (zS[0]<<24)+(zS[1]<<16)+(zS[2]<<8)+zS[3];
if( rc==SQLITE_OK ){
rc = pRealFile->pMethods->xRead(pRealFile, zS, 4, pReal->nBlob-4);
if( zS[0] || zS[1] || zS[2] || zS[3] ){
pReal->nJournal = pReal->nBlob;
}
}
}
if( rc==SQLITE_OK ){
pReal->pNext = pFsVfs->pFileList;
if( pReal->pNext ){
pReal->pNext->ppThis = &pReal->pNext;
}
pReal->ppThis = &pFsVfs->pFileList;
pFsVfs->pFileList = pReal;
}
}
open_out:
if( pReal ){
if( rc==SQLITE_OK ){
p->pReal = pReal;
pReal->nRef++;
}else{
if( pReal->pFile->pMethods ){
pReal->pFile->pMethods->xClose(pReal->pFile);
}
sqlite3_free(pReal);
}
}
return rc;
}
/*
** Delete the file located at zPath. If the dirSync argument is true,
** ensure the file-system modifications are synced to disk before
** returning.
*/
static int fsDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
int rc = SQLITE_OK;
fs_vfs_t *pFsVfs = (fs_vfs_t *)pVfs;
fs_real_file *pReal;
sqlite3_file *pF;
int nName = (int)strlen(zPath) - 8;
assert(strlen("-journal")==8);
assert(strcmp("-journal", &zPath[nName])==0);
pReal = pFsVfs->pFileList;
for(; pReal && strncmp(pReal->zName, zPath, nName); pReal=pReal->pNext);
if( pReal ){
pF = pReal->pFile;
rc = pF->pMethods->xWrite(pF, "\0\0\0\0", 4, pReal->nBlob-BLOCKSIZE);
if( rc==SQLITE_OK ){
pReal->nJournal = 0;
}
}
return rc;
}
/*
** Test for access permissions. Return true if the requested permission
** is available, or false otherwise.
*/
static int fsAccess(
sqlite3_vfs *pVfs,
const char *zPath,
int flags,
int *pResOut
){
fs_vfs_t *pFsVfs = (fs_vfs_t *)pVfs;
fs_real_file *pReal;
int isJournal = 0;
int nName = (int)strlen(zPath);
if( flags!=SQLITE_ACCESS_EXISTS ){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xAccess(pParent, zPath, flags, pResOut);
}
assert(strlen("-journal")==8);
if( nName>8 && strcmp("-journal", &zPath[nName-8])==0 ){
nName -= 8;
isJournal = 1;
}
pReal = pFsVfs->pFileList;
for(; pReal && strncmp(pReal->zName, zPath, nName); pReal=pReal->pNext);
*pResOut = (pReal && (!isJournal || pReal->nJournal>0));
return SQLITE_OK;
}
/*
** Populate buffer zOut with the full canonical pathname corresponding
** to the pathname in zPath. zOut is guaranteed to point to a buffer
** of at least (FS_MAX_PATHNAME+1) bytes.
*/
static int fsFullPathname(
sqlite3_vfs *pVfs, /* Pointer to vfs object */
const char *zPath, /* Possibly relative input path */
int nOut, /* Size of output buffer in bytes */
char *zOut /* Output buffer */
){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xFullPathname(pParent, zPath, nOut, zOut);
}
/*
** Open the dynamic library located at zPath and return a handle.
*/
static void *fsDlOpen(sqlite3_vfs *pVfs, const char *zPath){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xDlOpen(pParent, zPath);
}
/*
** Populate the buffer zErrMsg (size nByte bytes) with a human readable
** utf-8 string describing the most recent error encountered associated
** with dynamic libraries.
*/
static void fsDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
pParent->xDlError(pParent, nByte, zErrMsg);
}
/*
** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
*/
static void (*fsDlSym(sqlite3_vfs *pVfs, void *pH, const char *zSym))(void){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xDlSym(pParent, pH, zSym);
}
/*
** Close the dynamic library handle pHandle.
*/
static void fsDlClose(sqlite3_vfs *pVfs, void *pHandle){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
pParent->xDlClose(pParent, pHandle);
}
/*
** Populate the buffer pointed to by zBufOut with nByte bytes of
** random data.
*/
static int fsRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xRandomness(pParent, nByte, zBufOut);
}
/*
** Sleep for nMicro microseconds. Return the number of microseconds
** actually slept.
*/
static int fsSleep(sqlite3_vfs *pVfs, int nMicro){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xSleep(pParent, nMicro);
}
/*
** Return the current time as a Julian Day number in *pTimeOut.
*/
static int fsCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
sqlite3_vfs *pParent = ((fs_vfs_t *)pVfs)->pParent;
return pParent->xCurrentTime(pParent, pTimeOut);
}
/*
** This procedure registers the fs vfs with SQLite. If the argument is
** true, the fs vfs becomes the new default vfs. It is the only publicly
** available function in this file.
*/
int fs_register(void){
if( fs_vfs.pParent ) return SQLITE_OK;
fs_vfs.pParent = sqlite3_vfs_find(0);
fs_vfs.base.mxPathname = fs_vfs.pParent->mxPathname;
fs_vfs.base.szOsFile = MAX(sizeof(tmp_file), sizeof(fs_file));
return sqlite3_vfs_register(&fs_vfs.base, 0);
}
#ifdef SQLITE_TEST
int SqlitetestOnefile_Init() {return fs_register();}
#endif
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