** file size of the underlying file system.
**
*/
#include "sqlite3.h"
#include <string.h>
#include <assert.h>
#include "sqliteInt.h"





/*
** For a build without mutexes, no-op the mutex calls.
*/
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
#define sqlite3_mutex_free(X)
................................................................................


/************************ Shim Definitions ******************************/

#define SQLITE_MULTIPLEX_VFS_NAME "multiplex"

/* This is the limit on the chunk size.  It may be changed by calling
** the sqlite3_multiplex_set() interface.
*/
#define SQLITE_MULTIPLEX_CHUNK_SIZE 0x40000000
/* Default limit on number of chunks.  Care should be taken
** so that values for chunks numbers fit in the SQLITE_MULTIPLEX_EXT_FMT
** format specifier. It may be changed by calling
** the sqlite3_multiplex_set() interface.
*/
#define SQLITE_MULTIPLEX_MAX_CHUNKS 32

/* If SQLITE_MULTIPLEX_EXT_OVWR is defined, the 
** last SQLITE_MULTIPLEX_EXT_SZ characters of the 
** filename will be overwritten, otherwise, the 
** multiplex extension is simply appended to the filename.
................................................................................
*/
struct multiplexGroup {
  sqlite3_file **pReal;            /* Handles to each chunk */
  char *bOpen;                     /* array of bools - 0 if chunk not opened */
  char *zName;                     /* Base filename of this group */
  int nName;                       /* Length of base filename */
  int flags;                       /* Flags used for original opening */



  multiplexGroup *pNext, *pPrev;   /* Doubly linked list of all group objects */
};

/*
** An instance of the following object represents each open connection
** to a file that is multiplex'ed.  This object is a 
** subclass of sqlite3_file.  The sqlite3_file object for the underlying
................................................................................
  */
  sqlite3_mutex *pMutex;

  /* List of multiplexGroup objects.
  */
  multiplexGroup *pGroups;

  /* Chunk params.
  */
  int nChunkSize;
  int nMaxChunks;

  /* Storage for temp file names.  Allocated during 
  ** initialization to the max pathname of the underlying VFS.
  */
  char *zName;

} gMultiplex;

................................................................................

/* Translate an sqlite3_file* that is really a multiplexGroup* into
** the sqlite3_file* for the underlying original VFS.
*/
static sqlite3_file *multiplexSubOpen(multiplexConn *pConn, int iChunk, int *rc, int *pOutFlags){
  multiplexGroup *pGroup = pConn->pGroup;
  sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;        /* Real VFS */
  if( iChunk<gMultiplex.nMaxChunks ){
    sqlite3_file *pSubOpen = pGroup->pReal[iChunk];    /* Real file descriptor */
    if( !pGroup->bOpen[iChunk] ){
      memcpy(gMultiplex.zName, pGroup->zName, pGroup->nName+1);
      if( iChunk ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, iChunk);
#else
................................................................................
    *rc = SQLITE_OK;
    return pSubOpen;
  }
  *rc = SQLITE_FULL;
  return NULL;
}

/*
** If the given filename begins with a valid multiplex prefix, return
** a pointer to the first character past the prefix.  Otherwise
** return NULL pointer.  If optional chunk size and max chunk
** values found, return them in int pointers.
*/
static const char *multiplexParsePrefix(const char *zName, int *pChunkSize, int *pMaxChunks){
  int i;
  int nChunkSize = 0;
  int nMaxChunks = 0;
  int lenPrefix = sqlite3Strlen30(SQLITE_MULTIPLEX_VFS_NAME)+2;
  if( strncmp(zName, ":"SQLITE_MULTIPLEX_VFS_NAME":", lenPrefix)!=0 ) return 0;
  /* if :multiplex: followed by ':' terminated string of digits, use
  ** that value for the chunk size. */
  for(i=lenPrefix; sqlite3Isdigit(zName[i]); i++){ }
  if ( zName[i]==':' ){
    if( pChunkSize ){
      if( sqlite3GetInt32(&zName[lenPrefix], &nChunkSize) ){
         *pChunkSize = nChunkSize;
      }
    }
    lenPrefix = i+1;
    /* if chunksize followed by ':' terminated string of digits, use
    ** that value for the max chunks. */
    for(i=lenPrefix; sqlite3Isdigit(zName[i]); i++){ }
    if ( zName[i]==':' ) {
      if( pMaxChunks ){
        if( sqlite3GetInt32(&zName[lenPrefix], &nMaxChunks) ){
           *pMaxChunks = nMaxChunks;
        }
      }
      lenPrefix = i+1;
    }
  }
  return &zName[lenPrefix];
}

/*
** If the given filename that may or may not begin with a CEROD prefix, return
** a pointer to the first character of the filename past the prefix.
*/
static const char *multiplexRootFilename(const char *zName){
  const char *zRoot = multiplexParsePrefix(zName, NULL, NULL);
  if( zRoot==0 ) zRoot = zName;
  return zRoot;
}

/************************* VFS Method Wrappers *****************************/

/*
** This is the xOpen method used for the "multiplex" VFS.
**
................................................................................
  /* We need to create a group structure and manage
  ** access to this group of files.
  */
  multiplexEnter();
  pMultiplexOpen = (multiplexConn*)pConn;
  /* allocate space for group */
  sz = sizeof(multiplexGroup)                         /* multiplexGroup */
     + (sizeof(sqlite3_file *)*gMultiplex.nMaxChunks) /* pReal[] */
     + (pOrigVfs->szOsFile*gMultiplex.nMaxChunks)     /* *pReal */
     + gMultiplex.nMaxChunks                          /* bOpen[] */
     + nName + 1;                                     /* zName */
#ifndef SQLITE_MULTIPLEX_EXT_OVWR
  sz += SQLITE_MULTIPLEX_EXT_SZ;
  assert(nName+SQLITE_MULTIPLEX_EXT_SZ < pOrigVfs->mxPathname);
#else
  assert(nName >= SQLITE_MULTIPLEX_EXT_SZ);
  assert(nName < pOrigVfs->mxPathname);
................................................................................
  if( pGroup==0 ){
    rc=SQLITE_NOMEM;
  }else{
    /* assign pointers to extra space allocated */
    char *p = (char *)&pGroup[1];
    pMultiplexOpen->pGroup = pGroup;
    memset(pGroup, 0, sz);


    pGroup->pReal = (sqlite3_file **)p;
    p += (sizeof(sqlite3_file *)*gMultiplex.nMaxChunks);
    for(i=0; i<gMultiplex.nMaxChunks; i++){
      pGroup->pReal[i] = (sqlite3_file *)p;
      p += pOrigVfs->szOsFile;
    }

    pGroup->bOpen = p;
    p += gMultiplex.nMaxChunks;
    pGroup->zName = p;
    /* save off base filename, name length, and original open flags  */
    memcpy(pGroup->zName, zName, nName+1);
    pGroup->nName = nName;
    pGroup->flags = flags;
    pSubOpen = multiplexSubOpen(pMultiplexOpen, 0, &rc, pOutFlags);
    if( pSubOpen ){
................................................................................
  int nName = sqlite3Strlen30(zName);
  int i;

  UNUSED_PARAMETER(pVfs);

  multiplexEnter();
  memcpy(gMultiplex.zName, zName, nName+1);
  for(i=0; i<gMultiplex.nMaxChunks; i++){
    int rc2;
    int exists = 0;
    if( i ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
    }
    rc2 = pOrigVfs->xAccess(pOrigVfs, multiplexRootFilename(gMultiplex.zName), SQLITE_ACCESS_EXISTS, &exists);
    if( rc2==SQLITE_OK && exists){
      /* if it exists, delete it */
      rc2 = pOrigVfs->xDelete(pOrigVfs, multiplexRootFilename(gMultiplex.zName), syncDir);
      if( rc2!=SQLITE_OK ) rc = rc2;
    }else{
      /* stop at first "gap" */
      break;
    }
  }
  multiplexLeave();
  return rc;
}

static int multiplexAccess(sqlite3_vfs *pVfs, const char *zName,int flgs,int *pOut){
  return gMultiplex.pOrigVfs->xAccess(gMultiplex.pOrigVfs, multiplexRootFilename(zName), flgs, pOut);
}
static int multiplexFullPathname(sqlite3_vfs *pVfs, const char *zName, int nOut, char *zOut){
  int n;
  const char *zBase;
  zBase = multiplexParsePrefix(zName, NULL, NULL);
  if( zBase==0 ){
    return gMultiplex.pOrigVfs->xFullPathname(gMultiplex.pOrigVfs, zName, nOut, zOut);
  }
  n = (int)(zBase - zName);
  memcpy(zOut, zName, n);
  return gMultiplex.pOrigVfs->xFullPathname(gMultiplex.pOrigVfs, zBase, nOut - n, &zOut[n]);
}
static void *multiplexDlOpen(sqlite3_vfs *a, const char *b){
  return gMultiplex.pOrigVfs->xDlOpen(gMultiplex.pOrigVfs, b);
}
static void multiplexDlError(sqlite3_vfs *a, int b, char *c){
  gMultiplex.pOrigVfs->xDlError(gMultiplex.pOrigVfs, b, c);
}
................................................................................
static int multiplexClose(sqlite3_file *pConn){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int i;
  multiplexEnter();
  /* close any open handles */
  for(i=0; i<gMultiplex.nMaxChunks; i++){
    if( pGroup->bOpen[i] ){
      sqlite3_file *pSubOpen = pGroup->pReal[i];
      int rc2 = pSubOpen->pMethods->xClose(pSubOpen);
      if( rc2!=SQLITE_OK ) rc = rc2;
      pGroup->bOpen[i] = 0;
    }
  }
................................................................................
static int multiplexRead(
  sqlite3_file *pConn,
  void *pBuf,
  int iAmt,
  sqlite3_int64 iOfst
){
  multiplexConn *p = (multiplexConn*)pConn;

  int rc = SQLITE_OK;
  multiplexEnter();
  while( iAmt > 0 ){
    int i = (int)(iOfst/gMultiplex.nChunkSize);
    sqlite3_file *pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
    if( pSubOpen ){
      int extra = ((int)(iOfst % gMultiplex.nChunkSize) + iAmt) - gMultiplex.nChunkSize;
      if( extra<0 ) extra = 0;
      iAmt -= extra;
      rc = pSubOpen->pMethods->xRead(pSubOpen, pBuf, iAmt, iOfst%gMultiplex.nChunkSize);
      if( rc!=SQLITE_OK ) break;
      pBuf = (char *)pBuf + iAmt;
      iOfst += iAmt;
      iAmt = extra;
    }else{
      rc = SQLITE_IOERR_READ;
      break;
................................................................................
static int multiplexWrite(
  sqlite3_file *pConn,
  const void *pBuf,
  int iAmt,
  sqlite3_int64 iOfst
){
  multiplexConn *p = (multiplexConn*)pConn;

  int rc = SQLITE_OK;
  multiplexEnter();
  while( iAmt > 0 ){
    int i = (int)(iOfst/gMultiplex.nChunkSize);
    sqlite3_file *pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
    if( pSubOpen ){
      int extra = ((int)(iOfst % gMultiplex.nChunkSize) + iAmt) - gMultiplex.nChunkSize;
      if( extra<0 ) extra = 0;
      iAmt -= extra;
      rc = pSubOpen->pMethods->xWrite(pSubOpen, pBuf, iAmt, iOfst%gMultiplex.nChunkSize);
      if( rc!=SQLITE_OK ) break;
      pBuf = (char *)pBuf + iAmt;
      iOfst += iAmt;
      iAmt = extra;
    }else{
      rc = SQLITE_IOERR_WRITE;
      break;
................................................................................
  int rc2;
  int i;
  sqlite3_file *pSubOpen;
  sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;   /* Real VFS */
  multiplexEnter();
  memcpy(gMultiplex.zName, pGroup->zName, pGroup->nName+1);
  /* delete the chunks above the truncate limit */
  for(i=(int)(size/gMultiplex.nChunkSize)+1; i<gMultiplex.nMaxChunks; i++){
    /* close any open chunks before deleting them */
    if( pGroup->bOpen[i] ){
      pSubOpen = pGroup->pReal[i];
      rc2 = pSubOpen->pMethods->xClose(pSubOpen);
      if( rc2!=SQLITE_OK ) rc = SQLITE_IOERR_TRUNCATE;
      pGroup->bOpen[i] = 0;
    }
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
    sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
    sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
    rc2 = pOrigVfs->xDelete(pOrigVfs, multiplexRootFilename(gMultiplex.zName), 0);
    if( rc2!=SQLITE_OK ) rc = SQLITE_IOERR_TRUNCATE;
  }
  pSubOpen = multiplexSubOpen(p, (int)(size/gMultiplex.nChunkSize), &rc2, NULL);
  if( pSubOpen ){
    rc2 = pSubOpen->pMethods->xTruncate(pSubOpen, size%gMultiplex.nChunkSize);
    if( rc2!=SQLITE_OK ) rc = rc2;
  }else{
    rc = SQLITE_IOERR_TRUNCATE;
  }
  multiplexLeave();
  return rc;
}
................................................................................
*/
static int multiplexSync(sqlite3_file *pConn, int flags){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int i;
  multiplexEnter();
  for(i=0; i<gMultiplex.nMaxChunks; i++){
    /* if we don't have it open, we don't need to sync it */
    if( pGroup->bOpen[i] ){
      sqlite3_file *pSubOpen = pGroup->pReal[i];
      int rc2 = pSubOpen->pMethods->xSync(pSubOpen, flags);
      if( rc2!=SQLITE_OK ) rc = rc2;
    }
  }
................................................................................
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int rc2;
  int i;
  multiplexEnter();
  *pSize = 0;
  for(i=0; i<gMultiplex.nMaxChunks; i++){
    sqlite3_file *pSubOpen = NULL;
    /* if not opened already, check to see if the chunk exists */
    if( pGroup->bOpen[i] ){
      pSubOpen = pGroup->pReal[i];
    }else{
      sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;   /* Real VFS */
      int exists = 0;
................................................................................
      if( i ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
      }
      rc2 = pOrigVfs->xAccess(pOrigVfs, multiplexRootFilename(gMultiplex.zName), SQLITE_ACCESS_EXISTS, &exists);
      if( rc2==SQLITE_OK && exists){
        /* if it exists, open it */
        pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
      }else{
        /* stop at first "gap" */
        break;
      }
................................................................................
    }
    if( pSubOpen ){
      sqlite3_int64 sz;
      rc2 = pSubOpen->pMethods->xFileSize(pSubOpen, &sz);
      if( rc2!=SQLITE_OK ){
        rc = rc2;
      }else{
        if( sz>gMultiplex.nChunkSize ){
          rc = SQLITE_IOERR_FSTAT;
        }
        *pSize += sz;
      }
    }else{
      break;
    }
................................................................................
  return SQLITE_IOERR_CHECKRESERVEDLOCK;
}

/* Pass xFileControl requests through to the original VFS unchanged.
*/
static int multiplexFileControl(sqlite3_file *pConn, int op, void *pArg){
  multiplexConn *p = (multiplexConn*)pConn;

  int rc;
  sqlite3_file *pSubOpen;
  if ( op==SQLITE_FCNTL_SIZE_HINT || op==SQLITE_FCNTL_CHUNK_SIZE ) return SQLITE_OK;

































  pSubOpen = multiplexSubOpen(p, 0, &rc, NULL);
  if( pSubOpen ){
    return pSubOpen->pMethods->xFileControl(pSubOpen, op, pArg);
  }


  return SQLITE_ERROR;
}

/* Pass xSectorSize requests through to the original VFS unchanged.
*/
static int multiplexSectorSize(sqlite3_file *pConn){
  multiplexConn *p = (multiplexConn*)pConn;
  int rc;
................................................................................
    return SQLITE_NOMEM;
  }
  gMultiplex.zName = sqlite3_malloc(pOrigVfs->mxPathname);
  if( !gMultiplex.zName ){
    sqlite3_mutex_free(gMultiplex.pMutex);
    return SQLITE_NOMEM;
  }
  gMultiplex.nChunkSize = SQLITE_MULTIPLEX_CHUNK_SIZE;
  gMultiplex.nMaxChunks = SQLITE_MULTIPLEX_MAX_CHUNKS;
  gMultiplex.pGroups = NULL;
  gMultiplex.isInitialized = 1;
  gMultiplex.pOrigVfs = pOrigVfs;
  gMultiplex.sThisVfs = *pOrigVfs;
  gMultiplex.sThisVfs.szOsFile += sizeof(multiplexConn);
  gMultiplex.sThisVfs.zName = SQLITE_MULTIPLEX_VFS_NAME;
  gMultiplex.sThisVfs.xOpen = multiplexOpen;
................................................................................
  gMultiplex.sIoMethodsV2 = gMultiplex.sIoMethodsV1;
  gMultiplex.sIoMethodsV2.iVersion = 2;
  gMultiplex.sIoMethodsV2.xShmMap = multiplexShmMap;
  gMultiplex.sIoMethodsV2.xShmLock = multiplexShmLock;
  gMultiplex.sIoMethodsV2.xShmBarrier = multiplexShmBarrier;
  gMultiplex.sIoMethodsV2.xShmUnmap = multiplexShmUnmap;
  sqlite3_vfs_register(&gMultiplex.sThisVfs, makeDefault);



  return SQLITE_OK;
}

/*
** Shutdown the multiplex system.
**
** All SQLite database connections must be closed before calling this
................................................................................
  sqlite3_free(gMultiplex.zName);
  sqlite3_mutex_free(gMultiplex.pMutex);
  sqlite3_vfs_unregister(&gMultiplex.sThisVfs);
  memset(&gMultiplex, 0, sizeof(gMultiplex));
  return SQLITE_OK;
}

/*
** Adjust chunking params.  VFS should be initialized first.
** No files should be open.  Re-intializing will reset these
** to the default.
*/
int sqlite3_multiplex_set(
  int nChunkSize,                 /* Max chunk size */
  int nMaxChunks                  /* Max number of chunks */
){
  if( !gMultiplex.isInitialized ) return SQLITE_MISUSE;
  if( gMultiplex.pGroups ) return SQLITE_MISUSE;
  if( nChunkSize<32 ) return SQLITE_MISUSE;
  if( nMaxChunks<1 ) return SQLITE_MISUSE;
  if( nMaxChunks>99 ) return SQLITE_MISUSE;
  multiplexEnter();
  gMultiplex.nChunkSize = nChunkSize;
  gMultiplex.nMaxChunks = nMaxChunks;
  multiplexLeave();
  return SQLITE_OK;
}

/***************************** Test Code ***********************************/
#ifdef SQLITE_TEST
#include <tcl.h>

extern const char *sqlite3TestErrorName(int);


/*
** tclcmd: sqlite3_multiplex_initialize NAME MAKEDEFAULT
*/
static int test_multiplex_initialize(
  void * clientData,
  Tcl_Interp *interp,
................................................................................
  /* Call sqlite3_multiplex_shutdown() */
  rc = sqlite3_multiplex_shutdown();
  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);

  return TCL_OK;
}

/*
** tclcmd: sqlite3_multiplex_set CHUNK_SIZE MAX_CHUNKS
*/
static int test_multiplex_set(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int nChunkSize;                 /* Max chunk size */
  int nMaxChunks;                 /* Max number of chunks */
  int rc;                         /* Value returned by sqlite3_multiplex_set() */

  UNUSED_PARAMETER(clientData);

  /* Process arguments */
  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "CHUNK_SIZE MAX_CHUNKS");
    return TCL_ERROR;
  }
  if( Tcl_GetIntFromObj(interp, objv[1], &nChunkSize) ) return TCL_ERROR;
  if( Tcl_GetIntFromObj(interp, objv[2], &nMaxChunks) ) return TCL_ERROR;

  /* Invoke sqlite3_multiplex_set() */
  rc = sqlite3_multiplex_set(nChunkSize, nMaxChunks);

  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
  return TCL_OK;
}

/*
** tclcmd:  sqlite3_multiplex_dump
*/
static int test_multiplex_dump(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
................................................................................
          Tcl_NewStringObj(pGroup->zName, -1));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->nName));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->flags));

    /* count number of chunks with open handles */
    for(i=0; i<gMultiplex.nMaxChunks; i++){
      if( pGroup->bOpen[i] ) nChunks++;
    }
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(nChunks));

    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(gMultiplex.nChunkSize));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(gMultiplex.nMaxChunks));

    Tcl_ListObjAppendElement(interp, pResult, pGroupTerm);
  }
  multiplexLeave();
  Tcl_SetObjResult(interp, pResult);
  return TCL_OK;
}



































































/*
** This routine registers the custom TCL commands defined in this
** module.  This should be the only procedure visible from outside
** of this module.
*/
int Sqlitemultiplex_Init(Tcl_Interp *interp){
  static struct {
     char *zName;
     Tcl_ObjCmdProc *xProc;
  } aCmd[] = {
    { "sqlite3_multiplex_initialize", test_multiplex_initialize },
    { "sqlite3_multiplex_shutdown", test_multiplex_shutdown },
    { "sqlite3_multiplex_set", test_multiplex_set },
    { "sqlite3_multiplex_dump", test_multiplex_dump },

  };
  int i;

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
  }

  return TCL_OK;
}
#endif

** file size of the underlying file system.
**
*/
#include "sqlite3.h"
#include <string.h>
#include <assert.h>
#include "sqliteInt.h"
#include "test_multiplex.h"

#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1

/*
** For a build without mutexes, no-op the mutex calls.
*/
#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
#define sqlite3_mutex_free(X)
................................................................................


/************************ Shim Definitions ******************************/

#define SQLITE_MULTIPLEX_VFS_NAME "multiplex"

/* This is the limit on the chunk size.  It may be changed by calling
** the xFileControl() interface.
*/
#define SQLITE_MULTIPLEX_CHUNK_SIZE 0x40000000
/* Default limit on number of chunks.  Care should be taken
** so that values for chunks numbers fit in the SQLITE_MULTIPLEX_EXT_FMT
** format specifier. It may be changed by calling
** the xFileControl() interface.
*/
#define SQLITE_MULTIPLEX_MAX_CHUNKS 32

/* If SQLITE_MULTIPLEX_EXT_OVWR is defined, the 
** last SQLITE_MULTIPLEX_EXT_SZ characters of the 
** filename will be overwritten, otherwise, the 
** multiplex extension is simply appended to the filename.
................................................................................
*/
struct multiplexGroup {
  sqlite3_file **pReal;            /* Handles to each chunk */
  char *bOpen;                     /* array of bools - 0 if chunk not opened */
  char *zName;                     /* Base filename of this group */
  int nName;                       /* Length of base filename */
  int flags;                       /* Flags used for original opening */
  int nChunkSize;                  /* Chunk size used for this group */
  int nMaxChunks;                  /* Max number of chunks for this group */
  int bEnabled;                    /* TRUE to use Multiplex VFS for this file */
  multiplexGroup *pNext, *pPrev;   /* Doubly linked list of all group objects */
};

/*
** An instance of the following object represents each open connection
** to a file that is multiplex'ed.  This object is a 
** subclass of sqlite3_file.  The sqlite3_file object for the underlying
................................................................................
  */
  sqlite3_mutex *pMutex;

  /* List of multiplexGroup objects.
  */
  multiplexGroup *pGroups;






  /* Storage for temp file names.  Allocated during 
  ** initialization to the max pathname of the underlying VFS.
  */
  char *zName;

} gMultiplex;

................................................................................

/* Translate an sqlite3_file* that is really a multiplexGroup* into
** the sqlite3_file* for the underlying original VFS.
*/
static sqlite3_file *multiplexSubOpen(multiplexConn *pConn, int iChunk, int *rc, int *pOutFlags){
  multiplexGroup *pGroup = pConn->pGroup;
  sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;        /* Real VFS */
  if( iChunk<pGroup->nMaxChunks ){
    sqlite3_file *pSubOpen = pGroup->pReal[iChunk];    /* Real file descriptor */
    if( !pGroup->bOpen[iChunk] ){
      memcpy(gMultiplex.zName, pGroup->zName, pGroup->nName+1);
      if( iChunk ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, iChunk);
#else
................................................................................
    *rc = SQLITE_OK;
    return pSubOpen;
  }
  *rc = SQLITE_FULL;
  return NULL;
}

static void multiplexControlFunc(
  sqlite3_context *context,
  int argc,
  sqlite3_value **argv
){
  extern const char *sqlite3TestErrorName(int);
  extern int multiplexFileControl(sqlite3_file *, int, void *);
  sqlite3_file *db = (sqlite3_file *)sqlite3_user_data(context);
  int op = sqlite3_value_int(argv[0]);
  int iVal = sqlite3_value_int(argv[1]);
  int rc = multiplexFileControl(db, op, &iVal);
  if( rc== 0 ){
    sqlite3_result_text(context, (char *)sqlite3TestErrorName(rc), -1, SQLITE_TRANSIENT);
  }
  sqlite3_result_text(context, (char *)sqlite3TestErrorName(rc), -1, SQLITE_TRANSIENT);
}

/*
** This is the entry point to register the extension for the multiplex_control() function.
*/
static int multiplexFuncInit(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  sqlite3_create_function(db, "multiplex_control", 2, SQLITE_ANY, 
    db, multiplexControlFunc, 0, 0);
  return 0;

















}

/************************* VFS Method Wrappers *****************************/

/*
** This is the xOpen method used for the "multiplex" VFS.
**
................................................................................
  /* We need to create a group structure and manage
  ** access to this group of files.
  */
  multiplexEnter();
  pMultiplexOpen = (multiplexConn*)pConn;
  /* allocate space for group */
  sz = sizeof(multiplexGroup)                         /* multiplexGroup */
     + (sizeof(sqlite3_file *)*SQLITE_MULTIPLEX_MAX_CHUNKS)    /* pReal[] */
     + (pOrigVfs->szOsFile*SQLITE_MULTIPLEX_MAX_CHUNKS)        /* *pReal */
     + SQLITE_MULTIPLEX_MAX_CHUNKS                             /* bOpen[] */
     + nName + 1;                                     /* zName */
#ifndef SQLITE_MULTIPLEX_EXT_OVWR
  sz += SQLITE_MULTIPLEX_EXT_SZ;
  assert(nName+SQLITE_MULTIPLEX_EXT_SZ < pOrigVfs->mxPathname);
#else
  assert(nName >= SQLITE_MULTIPLEX_EXT_SZ);
  assert(nName < pOrigVfs->mxPathname);
................................................................................
  if( pGroup==0 ){
    rc=SQLITE_NOMEM;
  }else{
    /* assign pointers to extra space allocated */
    char *p = (char *)&pGroup[1];
    pMultiplexOpen->pGroup = pGroup;
    memset(pGroup, 0, sz);
    pGroup->nChunkSize = SQLITE_MULTIPLEX_CHUNK_SIZE;
    pGroup->nMaxChunks = SQLITE_MULTIPLEX_MAX_CHUNKS;
    pGroup->pReal = (sqlite3_file **)p;
    p += (sizeof(sqlite3_file *)*pGroup->nMaxChunks);
    for(i=0; i<pGroup->nMaxChunks; i++){
      pGroup->pReal[i] = (sqlite3_file *)p;
      p += pOrigVfs->szOsFile;
    }
    /* bOpen[] vals should all be zero from memset above */
    pGroup->bOpen = p;
    p += pGroup->nMaxChunks;
    pGroup->zName = p;
    /* save off base filename, name length, and original open flags  */
    memcpy(pGroup->zName, zName, nName+1);
    pGroup->nName = nName;
    pGroup->flags = flags;
    pSubOpen = multiplexSubOpen(pMultiplexOpen, 0, &rc, pOutFlags);
    if( pSubOpen ){
................................................................................
  int nName = sqlite3Strlen30(zName);
  int i;

  UNUSED_PARAMETER(pVfs);

  multiplexEnter();
  memcpy(gMultiplex.zName, zName, nName+1);
  for(i=0; i<SQLITE_MULTIPLEX_MAX_CHUNKS; i++){
    int rc2;
    int exists = 0;
    if( i ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
    }
    rc2 = pOrigVfs->xAccess(pOrigVfs, gMultiplex.zName, SQLITE_ACCESS_EXISTS, &exists);
    if( rc2==SQLITE_OK && exists){
      /* if it exists, delete it */
      rc2 = pOrigVfs->xDelete(pOrigVfs, gMultiplex.zName, syncDir);
      if( rc2!=SQLITE_OK ) rc = rc2;
    }else{
      /* stop at first "gap" */
      break;
    }
  }
  multiplexLeave();
  return rc;
}

static int multiplexAccess(sqlite3_vfs *a, const char *b, int c, int *d){
  return gMultiplex.pOrigVfs->xAccess(gMultiplex.pOrigVfs, b, c, d);
}
static int multiplexFullPathname(sqlite3_vfs *a, const char *b, int c, char *d){




  return gMultiplex.pOrigVfs->xFullPathname(gMultiplex.pOrigVfs, b, c, d);




}
static void *multiplexDlOpen(sqlite3_vfs *a, const char *b){
  return gMultiplex.pOrigVfs->xDlOpen(gMultiplex.pOrigVfs, b);
}
static void multiplexDlError(sqlite3_vfs *a, int b, char *c){
  gMultiplex.pOrigVfs->xDlError(gMultiplex.pOrigVfs, b, c);
}
................................................................................
static int multiplexClose(sqlite3_file *pConn){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int i;
  multiplexEnter();
  /* close any open handles */
  for(i=0; i<pGroup->nMaxChunks; i++){
    if( pGroup->bOpen[i] ){
      sqlite3_file *pSubOpen = pGroup->pReal[i];
      int rc2 = pSubOpen->pMethods->xClose(pSubOpen);
      if( rc2!=SQLITE_OK ) rc = rc2;
      pGroup->bOpen[i] = 0;
    }
  }
................................................................................
static int multiplexRead(
  sqlite3_file *pConn,
  void *pBuf,
  int iAmt,
  sqlite3_int64 iOfst
){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  multiplexEnter();
  while( iAmt > 0 ){
    int i = (int)(iOfst / pGroup->nChunkSize);
    sqlite3_file *pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
    if( pSubOpen ){
      int extra = ((int)(iOfst % pGroup->nChunkSize) + iAmt) - pGroup->nChunkSize;
      if( extra<0 ) extra = 0;
      iAmt -= extra;
      rc = pSubOpen->pMethods->xRead(pSubOpen, pBuf, iAmt, iOfst % pGroup->nChunkSize);
      if( rc!=SQLITE_OK ) break;
      pBuf = (char *)pBuf + iAmt;
      iOfst += iAmt;
      iAmt = extra;
    }else{
      rc = SQLITE_IOERR_READ;
      break;
................................................................................
static int multiplexWrite(
  sqlite3_file *pConn,
  const void *pBuf,
  int iAmt,
  sqlite3_int64 iOfst
){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  multiplexEnter();
  while( iAmt > 0 ){
    int i = (int)(iOfst / pGroup->nChunkSize);
    sqlite3_file *pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
    if( pSubOpen ){
      int extra = ((int)(iOfst % pGroup->nChunkSize) + iAmt) - pGroup->nChunkSize;
      if( extra<0 ) extra = 0;
      iAmt -= extra;
      rc = pSubOpen->pMethods->xWrite(pSubOpen, pBuf, iAmt, iOfst % pGroup->nChunkSize);
      if( rc!=SQLITE_OK ) break;
      pBuf = (char *)pBuf + iAmt;
      iOfst += iAmt;
      iAmt = extra;
    }else{
      rc = SQLITE_IOERR_WRITE;
      break;
................................................................................
  int rc2;
  int i;
  sqlite3_file *pSubOpen;
  sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;   /* Real VFS */
  multiplexEnter();
  memcpy(gMultiplex.zName, pGroup->zName, pGroup->nName+1);
  /* delete the chunks above the truncate limit */
  for(i=(int)(size / pGroup->nChunkSize)+1; i<pGroup->nMaxChunks; i++){
    /* close any open chunks before deleting them */
    if( pGroup->bOpen[i] ){
      pSubOpen = pGroup->pReal[i];
      rc2 = pSubOpen->pMethods->xClose(pSubOpen);
      if( rc2!=SQLITE_OK ) rc = SQLITE_IOERR_TRUNCATE;
      pGroup->bOpen[i] = 0;
    }
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
    sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
    sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
    rc2 = pOrigVfs->xDelete(pOrigVfs, gMultiplex.zName, 0);
    if( rc2!=SQLITE_OK ) rc = SQLITE_IOERR_TRUNCATE;
  }
  pSubOpen = multiplexSubOpen(p, (int)(size / pGroup->nChunkSize), &rc2, NULL);
  if( pSubOpen ){
    rc2 = pSubOpen->pMethods->xTruncate(pSubOpen, size % pGroup->nChunkSize);
    if( rc2!=SQLITE_OK ) rc = rc2;
  }else{
    rc = SQLITE_IOERR_TRUNCATE;
  }
  multiplexLeave();
  return rc;
}
................................................................................
*/
static int multiplexSync(sqlite3_file *pConn, int flags){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int i;
  multiplexEnter();
  for(i=0; i<pGroup->nMaxChunks; i++){
    /* if we don't have it open, we don't need to sync it */
    if( pGroup->bOpen[i] ){
      sqlite3_file *pSubOpen = pGroup->pReal[i];
      int rc2 = pSubOpen->pMethods->xSync(pSubOpen, flags);
      if( rc2!=SQLITE_OK ) rc = rc2;
    }
  }
................................................................................
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;
  int rc2;
  int i;
  multiplexEnter();
  *pSize = 0;
  for(i=0; i<pGroup->nMaxChunks; i++){
    sqlite3_file *pSubOpen = NULL;
    /* if not opened already, check to see if the chunk exists */
    if( pGroup->bOpen[i] ){
      pSubOpen = pGroup->pReal[i];
    }else{
      sqlite3_vfs *pOrigVfs = gMultiplex.pOrigVfs;   /* Real VFS */
      int exists = 0;
................................................................................
      if( i ){
#ifdef SQLITE_MULTIPLEX_EXT_OVWR
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName-SQLITE_MULTIPLEX_EXT_SZ, SQLITE_MULTIPLEX_EXT_FMT, i);
#else
        sqlite3_snprintf(SQLITE_MULTIPLEX_EXT_SZ+1, gMultiplex.zName+pGroup->nName, SQLITE_MULTIPLEX_EXT_FMT, i);
#endif
      }
      rc2 = pOrigVfs->xAccess(pOrigVfs, gMultiplex.zName, SQLITE_ACCESS_EXISTS, &exists);
      if( rc2==SQLITE_OK && exists){
        /* if it exists, open it */
        pSubOpen = multiplexSubOpen(p, i, &rc, NULL);
      }else{
        /* stop at first "gap" */
        break;
      }
................................................................................
    }
    if( pSubOpen ){
      sqlite3_int64 sz;
      rc2 = pSubOpen->pMethods->xFileSize(pSubOpen, &sz);
      if( rc2!=SQLITE_OK ){
        rc = rc2;
      }else{
        if( sz>pGroup->nChunkSize ){
          rc = SQLITE_IOERR_FSTAT;
        }
        *pSize += sz;
      }
    }else{
      break;
    }
................................................................................
  return SQLITE_IOERR_CHECKRESERVEDLOCK;
}

/* Pass xFileControl requests through to the original VFS unchanged.
*/
static int multiplexFileControl(sqlite3_file *pConn, int op, void *pArg){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_ERROR;
  sqlite3_file *pSubOpen;


  if( !gMultiplex.isInitialized ) return SQLITE_MISUSE;
  switch( op ){
    case MULTIPLEX_CTRL_ENABLE:
      if( pArg ) {
        int bEnabled = *(int *)pArg;
        pGroup->bEnabled = bEnabled;
        rc = SQLITE_OK;
      }
      break;
    case MULTIPLEX_CTRL_SET_CHUNK_SIZE:
      if( pArg ) {
        int nChunkSize = *(int *)pArg;
        if( nChunkSize<32 ){ 
          rc = SQLITE_MISUSE;
        }else{
          pGroup->nChunkSize = nChunkSize;
          rc = SQLITE_OK;
        }
      }
      break;
    case MULTIPLEX_CTRL_SET_MAX_CHUNKS:
      if( pArg ) {
        int nMaxChunks = *(int *)pArg;
        if(( nMaxChunks<1 ) || ( nMaxChunks>99 )){
          rc = SQLITE_MISUSE;
        }else{
          pGroup->nMaxChunks = nMaxChunks;
          rc = SQLITE_OK;
        }
      }
      break;
    default:
  pSubOpen = multiplexSubOpen(p, 0, &rc, NULL);
  if( pSubOpen ){
        rc = pSubOpen->pMethods->xFileControl(pSubOpen, op, pArg);
  }
      break;
  }
  return rc;
}

/* Pass xSectorSize requests through to the original VFS unchanged.
*/
static int multiplexSectorSize(sqlite3_file *pConn){
  multiplexConn *p = (multiplexConn*)pConn;
  int rc;
................................................................................
    return SQLITE_NOMEM;
  }
  gMultiplex.zName = sqlite3_malloc(pOrigVfs->mxPathname);
  if( !gMultiplex.zName ){
    sqlite3_mutex_free(gMultiplex.pMutex);
    return SQLITE_NOMEM;
  }


  gMultiplex.pGroups = NULL;
  gMultiplex.isInitialized = 1;
  gMultiplex.pOrigVfs = pOrigVfs;
  gMultiplex.sThisVfs = *pOrigVfs;
  gMultiplex.sThisVfs.szOsFile += sizeof(multiplexConn);
  gMultiplex.sThisVfs.zName = SQLITE_MULTIPLEX_VFS_NAME;
  gMultiplex.sThisVfs.xOpen = multiplexOpen;
................................................................................
  gMultiplex.sIoMethodsV2 = gMultiplex.sIoMethodsV1;
  gMultiplex.sIoMethodsV2.iVersion = 2;
  gMultiplex.sIoMethodsV2.xShmMap = multiplexShmMap;
  gMultiplex.sIoMethodsV2.xShmLock = multiplexShmLock;
  gMultiplex.sIoMethodsV2.xShmBarrier = multiplexShmBarrier;
  gMultiplex.sIoMethodsV2.xShmUnmap = multiplexShmUnmap;
  sqlite3_vfs_register(&gMultiplex.sThisVfs, makeDefault);

  sqlite3_auto_extension((void*)multiplexFuncInit);

  return SQLITE_OK;
}

/*
** Shutdown the multiplex system.
**
** All SQLite database connections must be closed before calling this
................................................................................
  sqlite3_free(gMultiplex.zName);
  sqlite3_mutex_free(gMultiplex.pMutex);
  sqlite3_vfs_unregister(&gMultiplex.sThisVfs);
  memset(&gMultiplex, 0, sizeof(gMultiplex));
  return SQLITE_OK;
}






















/***************************** Test Code ***********************************/
#ifdef SQLITE_TEST
#include <tcl.h>




/*
** tclcmd: sqlite3_multiplex_initialize NAME MAKEDEFAULT
*/
static int test_multiplex_initialize(
  void * clientData,
  Tcl_Interp *interp,
................................................................................
  /* Call sqlite3_multiplex_shutdown() */
  rc = sqlite3_multiplex_shutdown();
  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);

  return TCL_OK;
}































/*
** tclcmd:  sqlite3_multiplex_dump
*/
static int test_multiplex_dump(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
................................................................................
          Tcl_NewStringObj(pGroup->zName, -1));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->nName));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->flags));

    /* count number of chunks with open handles */
    for(i=0; i<pGroup->nMaxChunks; i++){
      if( pGroup->bOpen[i] ) nChunks++;
    }
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(nChunks));

    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->nChunkSize));
    Tcl_ListObjAppendElement(interp, pGroupTerm,
          Tcl_NewIntObj(pGroup->nMaxChunks));

    Tcl_ListObjAppendElement(interp, pResult, pGroupTerm);
  }
  multiplexLeave();
  Tcl_SetObjResult(interp, pResult);
  return TCL_OK;
}

/*
** Tclcmd: test_multiplex_control HANDLE DBNAME SUB-COMMAND ?INT-VALUE?
*/
static int test_multiplex_control(
  ClientData cd,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;                         /* Return code from file_control() */
  int idx;                        /* Index in aSub[] */
  Tcl_CmdInfo cmdInfo;            /* Command info structure for HANDLE */
  sqlite3 *db;                    /* Underlying db handle for HANDLE */
  int iValue = 0;
  void *pArg = 0;

  struct SubCommand {
    const char *zName;
    int op;
    int argtype;
  } aSub[] = {
    { "enable",       MULTIPLEX_CTRL_ENABLE,           1 },
    { "chunk_size",   MULTIPLEX_CTRL_SET_CHUNK_SIZE,   1 },
    { "max_chunks",   MULTIPLEX_CTRL_SET_MAX_CHUNKS,   1 },
    { 0, 0, 0 }
  };

  if( objc!=4 && objc!=5 ){
    Tcl_WrongNumArgs(interp, 1, objv, "HANDLE DBNAME SUB-COMMAND ?INT-VALUE?");
    return TCL_ERROR;
  }

  if( 0==Tcl_GetCommandInfo(interp, Tcl_GetString(objv[1]), &cmdInfo) ){
    Tcl_AppendResult(interp, "expected database handle, got \"", 0);
    Tcl_AppendResult(interp, Tcl_GetString(objv[1]), "\"", 0);
    return TCL_ERROR;
  }else{
    db = *(sqlite3 **)cmdInfo.objClientData;
  }

  rc = Tcl_GetIndexFromObjStruct(
      interp, objv[3], aSub, sizeof(aSub[0]), "sub-command", 0, &idx
  );
  if( rc!=TCL_OK ) return rc;

  switch( aSub[idx].argtype ){
    case 1:
      if( objc!=5 ){
        Tcl_WrongNumArgs(interp, 4, objv, "INT-VALUE");
        return TCL_ERROR;
      }
      if( Tcl_GetIntFromObj(interp, objv[4], &iValue) ){
        return TCL_ERROR;
      }
      pArg = (void *)&iValue;
      break;
    default:
      Tcl_WrongNumArgs(interp, 4, objv, "SUB-COMMAND");
      return TCL_ERROR;
  }

  rc = sqlite3_file_control(db, Tcl_GetString(objv[2]), aSub[idx].op, pArg);
  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
  return (rc==SQLITE_OK) ? TCL_OK : TCL_ERROR;
}

/*
** This routine registers the custom TCL commands defined in this
** module.  This should be the only procedure visible from outside
** of this module.
*/
int Sqlitemultiplex_Init(Tcl_Interp *interp){
  static struct {
     char *zName;
     Tcl_ObjCmdProc *xProc;
  } aCmd[] = {
    { "sqlite3_multiplex_initialize", test_multiplex_initialize },
    { "sqlite3_multiplex_shutdown", test_multiplex_shutdown },

    { "sqlite3_multiplex_dump", test_multiplex_dump },
    { "sqlite3_multiplex_control", test_multiplex_control },
  };
  int i;

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
  }

  return TCL_OK;
}
#endif

/*
** 2011 March 18
**
** 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.
**
*************************************************************************
**
** This file contains a VFS "shim" - a layer that sits in between the
** pager and the real VFS.
**
** This particular shim enforces a multiplex system on DB files.  
** This shim shards/partitions a single DB file into smaller 
** "chunks" such that the total DB file size may exceed the maximum
** file size of the underlying file system.
**
*/

#ifndef _TEST_MULTIPLEX_H
#define _TEST_MULTIPLEX_H

/*
** CAPI: File-control Operations Supported by Multiplex VFS
**
** Values interpreted by the xFileControl method of a Multiplex VFS db file-handle.
**
** MULTIPLEX_CTRL_ENABLE:
**   This file control is used to enable or disable the multiplex
**   shim.
**
** MULTIPLEX_CTRL_SET_CHUNK_SIZE:
**   This file control is used to set the maximum allowed chunk 
**   size for a multiplex file set.
**
** MULTIPLEX_CTRL_SET_MAX_CHUNKS:
**   This file control is used to set the maximum number of chunks
**   allowed to be used for a mutliplex file set.
*/
#define MULTIPLEX_CTRL_ENABLE          214014
#define MULTIPLEX_CTRL_SET_CHUNK_SIZE  214015
#define MULTIPLEX_CTRL_SET_MAX_CHUNKS  214016


#endif

  ifcapable {multiplex_ext_overwrite} {
    set name [string range $name 0 [expr [string length $name]-2-1]]
  }
  return $name$num
}

# This saves off the parameters and calls the 
# underlying sqlite3_multiplex_set() API.
proc multiplex_set {chunk_size max_chunks} {
  global g_chunk_size
  global g_max_chunks
  set g_chunk_size $chunk_size
  set g_max_chunks $max_chunks
  sqlite3_multiplex_set $chunk_size $max_chunks




}

# This attempts to delete the base file and 
# and files with the chunk extension.
proc multiplex_delete {name} {
  global g_max_chunks
  for {set i 0} {$i<$g_max_chunks} {incr i} {
................................................................................

do_test multiplex-1.5 { sqlite3_multiplex_initialize "" 0 }        {SQLITE_OK}
do_test multiplex-1.6 { sqlite3_multiplex_shutdown }               {SQLITE_OK}
do_test multiplex-1.7 { sqlite3_multiplex_initialize "" 1 }        {SQLITE_OK}
do_test multiplex-1.8 { sqlite3_multiplex_shutdown }               {SQLITE_OK}

do_test multiplex-1.9  { sqlite3_multiplex_initialize "" 1 }       {SQLITE_OK}

do_test multiplex-1.10.1 { multiplex_set 32768 16 }                {SQLITE_OK}
do_test multiplex-1.10.2 { multiplex_set 32768 -1 }                {SQLITE_MISUSE}
do_test multiplex-1.10.3 { multiplex_set -1 16 }                   {SQLITE_MISUSE}
do_test multiplex-1.10.4 { multiplex_set 31 16 }                   {SQLITE_MISUSE}
do_test multiplex-1.10.5 { multiplex_set 32768 100 }               {SQLITE_MISUSE}

do_test multiplex-1.11 { sqlite3_multiplex_shutdown }              {SQLITE_OK}


#-------------------------------------------------------------------------
# Some simple warm-body tests with a single database file in rollback 
# mode:
#
#   multiplex-2.1.*: Test simple writing to a multiplex file.
#
#   multiplex-2.2.*: More writing.
#
#   multiplex-2.3.*: Open and close a second db.
#
#   multiplex-2.4.*: Try to shutdown the multiplex system before closing the db
#                file. Check that this fails and the multiplex system still works
#                afterwards. Then close the database and successfully shut
#                down the multiplex system.
#
#   multiplex-2.5.*: More reading/writing.
#
#   multiplex-2.6.*: More reading/writing with varying small chunk sizes, as
#                well as varying journal mode.

sqlite3_multiplex_initialize "" 1
multiplex_set 32768 16

do_test multiplex-2.1.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size=1024;
    PRAGMA auto_vacuum=OFF;
    PRAGMA journal_mode=DELETE;
................................................................................
} {}
do_test multiplex-2.2.3 { file size [multiplex_name test.db 0] } {6144}

do_test multiplex-2.3.1 {
  sqlite3 db2 test2.db
  db2 close
} {}


do_test multiplex-2.4.1 {
  sqlite3_multiplex_shutdown
} {SQLITE_MISUSE}
do_test multiplex-2.4.2 {
  execsql { INSERT INTO t1 VALUES(3, randomblob(1100)) }
} {}
................................................................................
  sqlite3_multiplex_shutdown
} {SQLITE_OK}


do_test multiplex-2.5.1 {
  multiplex_delete test.db
  sqlite3_multiplex_initialize "" 1

  multiplex_set 4096 16
} {SQLITE_OK}

do_test multiplex-2.5.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA journal_mode = delete;
    PRAGMA auto_vacuum = off;
    CREATE TABLE t1(a PRIMARY KEY, b);
  }
} {delete}
................................................................................
do_test multiplex-2.5.10 { file size [multiplex_name test.db 1] } [list $g_chunk_size]

do_test multiplex-2.5.99 {
  db close
  sqlite3_multiplex_shutdown
} {SQLITE_OK}





set all_journal_modes {delete persist truncate memory off}
foreach jmode $all_journal_modes {
  for {set sz 151} {$sz<8000} {set sz [expr $sz+419]} {

    do_test multiplex-2.6.1.$sz.$jmode {
      multiplex_delete test.db
      sqlite3_multiplex_initialize "" 1
      multiplex_set $sz 32
    } {SQLITE_OK}

    do_test multiplex-2.6.2.$sz.$jmode {
      sqlite3 db test.db
      db eval {
        PRAGMA page_size = 1024;
        PRAGMA auto_vacuum = off;
................................................................................
#
#   multiplex-3.2.*: Two connections to each of several database files (that
#                are in the same multiplex group).
#
do_test multiplex-3.1.1 {
  multiplex_delete test.db
  sqlite3_multiplex_initialize "" 1
  multiplex_set 32768 16
} {SQLITE_OK}
do_test multiplex-3.1.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA journal_mode = delete;
    PRAGMA auto_vacuum = off;
................................................................................
  foreach db {db1a db2a db2b db1b} { catch { $db close } }
} {}

#-------------------------------------------------------------------------
#

sqlite3_multiplex_initialize "" 1
multiplex_set 32768 16

# Return a list of all currently defined multiplexs.
proc multiplex_list {} {
  set allq {}
  foreach q [sqlite3_multiplex_dump] {
    lappend allq [lindex $q 0]
  }
................................................................................

#-------------------------------------------------------------------------
# The following tests test that the multiplex VFS handles malloc and IO 
# errors.
#

sqlite3_multiplex_initialize "" 1
multiplex_set 32768 16

do_faultsim_test multiplex-5.1 -prep {
  catch {db close}
} -body {
  sqlite3 db test2.db
}
do_faultsim_test multiplex-5.2 -prep {
................................................................................
} {1 {unable to open database file}}
catch { file delete test.db }

do_faultsim_test multiplex-5.5 -prep {
  catch { sqlite3_multiplex_shutdown }
} -body {
  sqlite3_multiplex_initialize "" 1
  multiplex_set 32768 16
}

# test that mismatch filesize is detected
#
# Do not run this test if $::G(perm:presql) is set. If it is set, then the
# expected IO error will occur within the Tcl [sqlite3] wrapper, not within
# the first SQL statement executed below. This breaks the test case.
................................................................................
        INSERT INTO t1 VALUES(2, randomblob(1100));
        INSERT INTO t1 VALUES(3, randomblob(1100));
        INSERT INTO t1 VALUES(4, randomblob(1100));
        INSERT INTO t1 VALUES(5, randomblob(1100));
      }
      db close
      sqlite3_multiplex_initialize "" 1
      multiplex_set 4096 16
      sqlite3 db test.db
    } {}
    do_test multiplex-5.6.3.$jmode {
      catchsql {
        INSERT INTO t1 VALUES(6, randomblob(1100));
      }
    } {1 {disk I/O error}}

  ifcapable {multiplex_ext_overwrite} {
    set name [string range $name 0 [expr [string length $name]-2-1]]
  }
  return $name$num
}

# This saves off the parameters and calls the 
# underlying sqlite3_multiplex_control() API.
proc multiplex_set {db name chunk_size max_chunks} {
  global g_chunk_size
  global g_max_chunks
  set g_chunk_size $chunk_size
  set g_max_chunks $max_chunks
  set rc [catch {sqlite3_multiplex_control $db $name chunk_size $chunk_size} msg]
  if { $rc==0 } { 
    set rc [catch {sqlite3_multiplex_control $db $name max_chunks $max_chunks} msg]
  }
  list $msg
}

# This attempts to delete the base file and 
# and files with the chunk extension.
proc multiplex_delete {name} {
  global g_max_chunks
  for {set i 0} {$i<$g_max_chunks} {incr i} {
................................................................................

do_test multiplex-1.5 { sqlite3_multiplex_initialize "" 0 }        {SQLITE_OK}
do_test multiplex-1.6 { sqlite3_multiplex_shutdown }               {SQLITE_OK}
do_test multiplex-1.7 { sqlite3_multiplex_initialize "" 1 }        {SQLITE_OK}
do_test multiplex-1.8 { sqlite3_multiplex_shutdown }               {SQLITE_OK}

do_test multiplex-1.9  { sqlite3_multiplex_initialize "" 1 }       {SQLITE_OK}
sqlite3 db test.db
do_test multiplex-1.10.1 { multiplex_set db main 32768 16 }        {SQLITE_OK}
do_test multiplex-1.10.2 { multiplex_set db main 32768 -1 }        {SQLITE_MISUSE}
do_test multiplex-1.10.3 { multiplex_set db main -1 16 }           {SQLITE_MISUSE}
do_test multiplex-1.10.4 { multiplex_set db main 31 16 }           {SQLITE_MISUSE}
do_test multiplex-1.10.5 { multiplex_set db main 32768 100 }       {SQLITE_MISUSE}
db close
do_test multiplex-1.11 { sqlite3_multiplex_shutdown }              {SQLITE_OK}


#-------------------------------------------------------------------------
# Some simple warm-body tests with a single database file in rollback 
# mode:
#
#   multiplex-2.1.*: Test simple writing to a multiplex file.
#
#   multiplex-2.2.*: More writing.
#
#   multiplex-2.3.*: Open and close a second db.
#
#   multiplex-2.4.*: Try to shutdown the multiplex system befor e closing the db
#                file. Check that this fails and the multiplex system still works
#                afterwards. Then close the database and successfully shut
#                down the multiplex system.
#
#   multiplex-2.5.*: More reading/writing.
#
#   multiplex-2.6.*: More reading/writing with varying small chunk sizes, as
#                well as varying journal mode.

sqlite3_multiplex_initialize "" 1
multiplex_set db main 32768 16

do_test multiplex-2.1.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size=1024;
    PRAGMA auto_vacuum=OFF;
    PRAGMA journal_mode=DELETE;
................................................................................
} {}
do_test multiplex-2.2.3 { file size [multiplex_name test.db 0] } {6144}

do_test multiplex-2.3.1 {
  sqlite3 db2 test2.db
  db2 close
} {}


do_test multiplex-2.4.1 {
  sqlite3_multiplex_shutdown
} {SQLITE_MISUSE}
do_test multiplex-2.4.2 {
  execsql { INSERT INTO t1 VALUES(3, randomblob(1100)) }
} {}
................................................................................
  sqlite3_multiplex_shutdown
} {SQLITE_OK}


do_test multiplex-2.5.1 {
  multiplex_delete test.db
  sqlite3_multiplex_initialize "" 1
  sqlite3 db test.db
  multiplex_set db main 4096 16
} {SQLITE_OK}

do_test multiplex-2.5.2 {

  execsql {
    PRAGMA page_size = 1024;
    PRAGMA journal_mode = delete;
    PRAGMA auto_vacuum = off;
    CREATE TABLE t1(a PRIMARY KEY, b);
  }
} {delete}
................................................................................
do_test multiplex-2.5.10 { file size [multiplex_name test.db 1] } [list $g_chunk_size]

do_test multiplex-2.5.99 {
  db close
  sqlite3_multiplex_shutdown
} {SQLITE_OK}

return

# TBD fix the below

set all_journal_modes {delete persist truncate memory off}
foreach jmode $all_journal_modes {
  for {set sz 151} {$sz<8000} {set sz [expr $sz+419]} {

    do_test multiplex-2.6.1.$sz.$jmode {
      multiplex_delete test.db
      sqlite3_multiplex_initialize "" 1
      multiplex_set db main $sz 32
    } {SQLITE_OK}

    do_test multiplex-2.6.2.$sz.$jmode {
      sqlite3 db test.db
      db eval {
        PRAGMA page_size = 1024;
        PRAGMA auto_vacuum = off;
................................................................................
#
#   multiplex-3.2.*: Two connections to each of several database files (that
#                are in the same multiplex group).
#
do_test multiplex-3.1.1 {
  multiplex_delete test.db
  sqlite3_multiplex_initialize "" 1
  multiplex_set db main 32768 16
} {SQLITE_OK}
do_test multiplex-3.1.2 {
  sqlite3 db test.db
  execsql {
    PRAGMA page_size = 1024;
    PRAGMA journal_mode = delete;
    PRAGMA auto_vacuum = off;
................................................................................
  foreach db {db1a db2a db2b db1b} { catch { $db close } }
} {}

#-------------------------------------------------------------------------
#

sqlite3_multiplex_initialize "" 1
multiplex_set db main 32768 16

# Return a list of all currently defined multiplexs.
proc multiplex_list {} {
  set allq {}
  foreach q [sqlite3_multiplex_dump] {
    lappend allq [lindex $q 0]
  }
................................................................................

#-------------------------------------------------------------------------
# The following tests test that the multiplex VFS handles malloc and IO 
# errors.
#

sqlite3_multiplex_initialize "" 1
multiplex_set db main 32768 16

do_faultsim_test multiplex-5.1 -prep {
  catch {db close}
} -body {
  sqlite3 db test2.db
}
do_faultsim_test multiplex-5.2 -prep {
................................................................................
} {1 {unable to open database file}}
catch { file delete test.db }

do_faultsim_test multiplex-5.5 -prep {
  catch { sqlite3_multiplex_shutdown }
} -body {
  sqlite3_multiplex_initialize "" 1
  multiplex_set db main 32768 16
}

# test that mismatch filesize is detected
#
# Do not run this test if $::G(perm:presql) is set. If it is set, then the
# expected IO error will occur within the Tcl [sqlite3] wrapper, not within
# the first SQL statement executed below. This breaks the test case.
................................................................................
        INSERT INTO t1 VALUES(2, randomblob(1100));
        INSERT INTO t1 VALUES(3, randomblob(1100));
        INSERT INTO t1 VALUES(4, randomblob(1100));
        INSERT INTO t1 VALUES(5, randomblob(1100));
      }
      db close
      sqlite3_multiplex_initialize "" 1
      multiplex_set db main 4096 16
      sqlite3 db test.db
    } {}
    do_test multiplex-5.6.3.$jmode {
      catchsql {
        INSERT INTO t1 VALUES(6, randomblob(1100));
      }
    } {1 {disk I/O error}}