SQLite

  p->nPendingData = 0;
  p->azColumn = (char **)&p[1];
  p->pTokenizer = pTokenizer;
  p->nNodeSize = 1000;
  p->nMaxPendingData = FTS3_MAX_PENDING_DATA;
  p->bHasDocsize = (isFts4 && bNoDocsize==0);
  p->bHasStat = isFts4;
  TESTONLY( p->inTransaction = -1 );
  TESTONLY( p->mxSavepoint = -1 );
  fts3HashInit(&p->pendingTerms, FTS3_HASH_STRING, 1);

  /* Fill in the zName and zDb fields of the vtab structure. */
  zCsr = (char *)&p->azColumn[nCol];
  p->zName = zCsr;
  memcpy(zCsr, argv[2], nName);
  zCsr += nName;

}

/*
** Implementation of xBegin() method. This is a no-op.
*/
static int fts3BeginMethod(sqlite3_vtab *pVtab){
  UNUSED_PARAMETER(pVtab);
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  assert( p->nPendingData==0 );
  assert( p->inTransaction!=1 );
  TESTONLY( p->inTransaction = 1 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** Implementation of xCommit() method. This is a no-op. The contents of
** the pending-terms hash-table have already been flushed into the database
** by fts3SyncMethod().
*/
static int fts3CommitMethod(sqlite3_vtab *pVtab){
  UNUSED_PARAMETER(pVtab);
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  assert( p->nPendingData==0 );
  assert( p->inTransaction!=0 );
  TESTONLY( p->inTransaction = 0 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** Implementation of xRollback(). Discard the contents of the pending-terms
** hash-table. Any changes made to the database are reverted by SQLite.
*/
static int fts3RollbackMethod(sqlite3_vtab *pVtab){
  Fts3Table *p = (Fts3Table*)pVtab;
  sqlite3Fts3PendingTermsClear(p);
  assert( p->inTransaction!=0 );
  TESTONLY( p->inTransaction = 0 );
  TESTONLY( p->mxSavepoint = -1; );
  return SQLITE_OK;
}

/*
** Load the doclist associated with expression pExpr to pExpr->aDoclist.
** The loaded doclist contains positions as well as the document ids.
** This is used by the matchinfo(), snippet() and offsets() auxillary

    "ALTER TABLE %Q.'%q_segdir'   RENAME TO '%q_segdir';",
    p->zDb, p->zName, zName
  );
  return rc;
}

static int fts3SavepointMethod(sqlite3_vtab *pVtab, int iSavepoint){
  Fts3Table *p = (Fts3Table*)pVtab;
  UNUSED_PARAMETER(iSavepoint);
  assert( p->inTransaction );
  assert( p->mxSavepoint < iSavepoint );
  TESTONLY( p->mxSavepoint = iSavepoint );
  return sqlite3Fts3PendingTermsFlush(p);
}
static int fts3ReleaseMethod(sqlite3_vtab *pVtab, int iSavepoint){
  TESTONLY( Fts3Table *p = (Fts3Table*)pVtab );
  UNUSED_PARAMETER(iSavepoint);
  UNUSED_PARAMETER(pVtab);
  assert( p->inTransaction );
  assert( p->mxSavepoint >= iSavepoint );
  TESTONLY( p->mxSavepoint = iSavepoint-1 );
  return SQLITE_OK;
}
static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
  Fts3Table *p = (Fts3Table*)pVtab;
  UNUSED_PARAMETER(iSavepoint);
  assert( p->inTransaction );
  assert( p->mxSavepoint >= iSavepoint );
  TESTONLY( p->mxSavepoint = iSavepoint );
  sqlite3Fts3PendingTermsClear(p);
  return SQLITE_OK;
}

static const sqlite3_module fts3Module = {
  /* iVersion      */ 2,
  /* xCreate       */ fts3CreateMethod,
  /* xConnect      */ fts3ConnectMethod,

/*
** Internal types used by SQLite.
*/
typedef unsigned char u8;         /* 1-byte (or larger) unsigned integer */
typedef short int i16;            /* 2-byte (or larger) signed integer */
typedef unsigned int u32;         /* 4-byte unsigned integer */
typedef sqlite3_uint64 u64;       /* 8-byte unsigned integer */

/*
** Macro used to suppress compiler warnings for unused parameters.
*/
#define UNUSED_PARAMETER(x) (void)(x)

/*
** Activate assert() only if SQLITE_TEST is enabled.
*/
#if !defined(NDEBUG) && !defined(SQLITE_DEBUG) 
# define NDEBUG 1
#endif

/*
** The TESTONLY macro is used to enclose variable declarations or
** other bits of code that are needed to support the arguments
** within testcase() and assert() macros.
*/
#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
# define TESTONLY(X)  X
#else
# define TESTONLY(X)
#endif

#endif /* SQLITE_AMALGAMATION */

typedef struct Fts3Table Fts3Table;
typedef struct Fts3Cursor Fts3Cursor;
typedef struct Fts3Expr Fts3Expr;
typedef struct Fts3Phrase Fts3Phrase;
typedef struct Fts3PhraseToken Fts3PhraseToken;

  ** automatically. Variable iPrevDocid is the docid of the most recently
  ** inserted record.
  */
  int nMaxPendingData;
  int nPendingData;
  sqlite_int64 iPrevDocid;
  Fts3Hash pendingTerms;

#if defined(SQLITE_DEBUG)
  /* State variables used for validating that the transaction control
  ** methods of the virtual table are called at appropriate times.  These
  ** values do not contribution to the FTS computation; they are used for
  ** verifying the SQLite core.
  */
  int inTransaction;     /* True after xBegin but before xCommit/xRollback */
  int mxSavepoint;       /* Largest valid xSavepoint integer */
#endif
};

/*
** When the core wants to read from the virtual table, it creates a
** virtual table cursor (an instance of the following structure) using
** the xOpen method. Cursors are destroyed using the xClose method.
*/

){
  Fts3auxCursor *pCsr = (Fts3auxCursor *)pCursor;
  Fts3Table *pFts3 = ((Fts3auxTable *)pCursor->pVtab)->pFts3Tab;
  int rc;
  int isScan;

  UNUSED_PARAMETER(nVal);
  UNUSED_PARAMETER(idxStr);

  assert( idxStr==0 );
  assert( idxNum==FTS4AUX_EQ_CONSTRAINT || idxNum==0
       || idxNum==FTS4AUX_LE_CONSTRAINT || idxNum==FTS4AUX_GE_CONSTRAINT
       || idxNum==(FTS4AUX_LE_CONSTRAINT|FTS4AUX_GE_CONSTRAINT)
  );
  isScan = (idxNum!=FTS4AUX_EQ_CONSTRAINT);

     fts3auxRowidMethod,          /* xRowid        */
     0,                           /* xUpdate       */
     0,                           /* xBegin        */
     0,                           /* xSync         */
     0,                           /* xCommit       */
     0,                           /* xRollback     */
     0,                           /* xFindFunction */
     0,                           /* xRename       */
     0,                           /* xSavepoint    */
     0,                           /* xRelease      */
     0                            /* xRollbackTo   */
  };
  int rc;                         /* Return code */

  rc = sqlite3_create_module(db, "fts4aux", &fts3aux_module, 0);
  return rc;
}

#endif /* !defined(SQLITE_CORE) || defined(SQLITE_ENABLE_FTS3) */

    rc = sqlite3_exec(pRtree->db, zSql, 0, 0, 0);
    sqlite3_free(zSql);
  }
  return rc;
}

static sqlite3_module rtreeModule = {
  0,                          /* iVersion */
  rtreeCreate,                /* xCreate - create a table */
  rtreeConnect,               /* xConnect - connect to an existing table */
  rtreeBestIndex,             /* xBestIndex - Determine search strategy */
  rtreeDisconnect,            /* xDisconnect - Disconnect from a table */
  rtreeDestroy,               /* xDestroy - Drop a table */
  rtreeOpen,                  /* xOpen - open a cursor */
  rtreeClose,                 /* xClose - close a cursor */
  rtreeFilter,                /* xFilter - configure scan constraints */
  rtreeNext,                  /* xNext - advance a cursor */
  rtreeEof,                   /* xEof */
  rtreeColumn,                /* xColumn - read data */
  rtreeRowid,                 /* xRowid - read data */
  rtreeUpdate,                /* xUpdate - write data */
  0,                          /* xBegin - begin transaction */
  0,                          /* xSync - sync transaction */
  0,                          /* xCommit - commit transaction */
  0,                          /* xRollback - rollback transaction */
  0,                          /* xFindFunction - function overloading */
  rtreeRename,                /* xRename - rename the table */
  0,                          /* xSavepoint */
  0,                          /* xRelease */
  0                           /* xRollbackTo */
};

static int rtreeSqlInit(
  Rtree *pRtree, 
  sqlite3 *db, 
  const char *zDb, 
  const char *zPrefix, 

** The cell content is not freed or deallocated.  It is assumed that
** the cell content has been copied someplace else.  This routine just
** removes the reference to the cell from pPage.
**
** "sz" must be the number of bytes in the cell.
*/
static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){

  u32 pc;         /* Offset to cell content of cell being deleted */
  u8 *data;       /* pPage->aData */
  u8 *ptr;        /* Used to move bytes around within data[] */
  u8 *endPtr;     /* End of loop */
  int rc;         /* The return code */
  int hdr;        /* Beginning of the header.  0 most pages.  100 page 1 */

  if( *pRC ) return;

  assert( idx>=0 && idx<pPage->nCell );
  assert( sz==cellSize(pPage, idx) );

    return;
  }
  rc = freeSpace(pPage, pc, sz);
  if( rc ){
    *pRC = rc;
    return;
  }
  endPtr = &data[pPage->cellOffset + 2*pPage->nCell - 2];
  while( ptr<endPtr ){
    ptr[0] = ptr[2];
    ptr[1] = ptr[3];
    ptr += 2;
  }
  pPage->nCell--;
  put2byte(&data[hdr+3], pPage->nCell);
  pPage->nFree += 2;
}

/*

    FILE *trace = (db->flags & SQLITE_VdbeTrace)!=0 ? stdout : 0;
    sqlite3VdbeTrace(v, trace);
#endif
    assert( pParse->iCacheLevel==0 );  /* Disables and re-enables match */
    /* A minimum of one cursor is required if autoincrement is used
    *  See ticket [a696379c1f08866] */
    if( pParse->pAinc!=0 && pParse->nTab==0 ) pParse->nTab = 1;
    sqlite3VdbeMakeReady(v, pParse);


    pParse->rc = SQLITE_DONE;
    pParse->colNamesSet = 0;
  }else{
    pParse->rc = SQLITE_ERROR;
  }
  pParse->nTab = 0;
  pParse->nMem = 0;

    /* Delete the row */
#ifndef SQLITE_OMIT_VIRTUALTABLE
    if( IsVirtual(pTab) ){
      const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
      sqlite3VtabMakeWritable(pParse, pTab);
      sqlite3VdbeAddOp4(v, OP_VUpdate, 0, 1, iRowid, pVTab, P4_VTAB);
      sqlite3VdbeChangeP5(v, OE_Abort);
      sqlite3MayAbort(pParse);
    }else
#endif
    {
      int count = (pParse->nested==0);    /* True to count changes */
      sqlite3GenerateRowDelete(pParse, pTab, iCur, iRowid, count, pTrigger, OE_Default);
    }

  z = pExpr->u.zToken;
  assert( z!=0 );
  assert( z[0]!=0 );
  if( z[1]==0 ){
    /* Wildcard of the form "?".  Assign the next variable number */
    assert( z[0]=='?' );
    pExpr->iColumn = (ynVar)(++pParse->nVar);

















  }else{
    ynVar x = 0;
    u32 n = sqlite3Strlen30(z);
    if( z[0]=='?' ){
      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
      ** use it as the variable number */
      i64 i;
      int bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
      pExpr->iColumn = x = (ynVar)i;
      testcase( i==0 );
      testcase( i==1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
        x = 0;
      }
      if( i>pParse->nVar ){
        pParse->nVar = (int)i;
      }
    }else{
      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
      ** number as the prior appearance of the same name, or if the name
      ** has never appeared before, reuse the same variable number
      */
      ynVar i;


      for(i=0; i<pParse->nzVar; i++){
        if( pParse->azVar[i] && memcmp(pParse->azVar[i],z,n+1)==0 ){


          pExpr->iColumn = x = (ynVar)i+1;
          break;
        }
      }

      if( x==0 ) x = pExpr->iColumn = (ynVar)(++pParse->nVar);
    }
    if( x>0 ){

      if( x>pParse->nzVar ){
        char **a;
        a = sqlite3DbRealloc(db, pParse->azVar, x*sizeof(a[0]));

        if( a==0 ) return;  /* Error reported through db->mallocFailed */
        pParse->azVar = a;
        memset(&a[pParse->nzVar], 0, (x-pParse->nzVar)*sizeof(a[0]));
        pParse->nzVar = x;

      }
      if( z[0]!='?' || pParse->azVar[x-1]==0 ){
        sqlite3DbFree(db, pParse->azVar[x-1]);
        pParse->azVar[x-1] = sqlite3DbStrNDup(db, z, n);
      }
    }
  } 
  if( !pParse->nErr && pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
    sqlite3ErrorMsg(pParse, "too many SQL variables");
  }
}

#endif
    case TK_VARIABLE: {
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      assert( pExpr->u.zToken!=0 );
      assert( pExpr->u.zToken[0]!=0 );
      sqlite3VdbeAddOp2(v, OP_Variable, pExpr->iColumn, target);
      if( pExpr->u.zToken[1]!=0 ){
        assert( pExpr->u.zToken[0]=='?' 
             || strcmp(pExpr->u.zToken, pParse->azVar[pExpr->iColumn-1])==0 );
        sqlite3VdbeChangeP4(v, -1, pParse->azVar[pExpr->iColumn-1], P4_STATIC);
      }
      break;
    }
    case TK_REGISTER: {
      inReg = pExpr->iTable;
      break;
    }

*/
struct unixShmNode {
  unixInodeInfo *pInode;     /* unixInodeInfo that owns this SHM node */
  sqlite3_mutex *mutex;      /* Mutex to access this object */
  char *zFilename;           /* Name of the mmapped file */
  int h;                     /* Open file descriptor */
  int szRegion;              /* Size of shared-memory regions */
  u16 nRegion;               /* Size of array apRegion */
  u8 isReadonly;             /* True if read-only */
  char **apRegion;           /* Array of mapped shared-memory regions */
  int nRef;                  /* Number of unixShm objects pointing to this */
  unixShm *pFirst;           /* All unixShm objects pointing to this */
#ifdef SQLITE_DEBUG
  u8 exclMask;               /* Mask of exclusive locks held */
  u8 sharedMask;             /* Mask of shared locks held */
  u8 nextShmId;              /* Next available unixShm.id value */

      goto shm_open_err;
    }

    if( pInode->bProcessLock==0 ){
      pShmNode->h = robust_open(zShmFilename, O_RDWR|O_CREAT,
                               (sStat.st_mode & 0777));
      if( pShmNode->h<0 ){
        const char *zRO;
        zRO = sqlite3_uri_parameter(pDbFd->zPath, "readonly_shm");
        if( zRO && sqlite3GetBoolean(zRO) ){
          pShmNode->h = robust_open(zShmFilename, O_RDONLY,
                                    (sStat.st_mode & 0777));
          pShmNode->isReadonly = 1;
        }
        if( pShmNode->h<0 ){
          rc = unixLogError(SQLITE_CANTOPEN_BKPT, "open", zShmFilename);
          goto shm_open_err;
        }
      }
  
      /* Check to see if another process is holding the dead-man switch.
      ** If not, truncate the file to zero length. 
      */
      rc = SQLITE_OK;
      if( unixShmSystemLock(pShmNode, F_WRLCK, UNIX_SHM_DMS, 1)==SQLITE_OK ){

      rc = SQLITE_IOERR_NOMEM;
      goto shmpage_out;
    }
    pShmNode->apRegion = apNew;
    while(pShmNode->nRegion<=iRegion){
      void *pMem;
      if( pShmNode->h>=0 ){
        pMem = mmap(0, szRegion,
            pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE, 
            MAP_SHARED, pShmNode->h, pShmNode->nRegion*szRegion
        );
        if( pMem==MAP_FAILED ){
          rc = unixLogError(SQLITE_IOERR_SHMMAP, "mmap", pShmNode->zFilename);
          goto shmpage_out;
        }
      }else{

shmpage_out:
  if( pShmNode->nRegion>iRegion ){
    *pp = pShmNode->apRegion[iRegion];
  }else{
    *pp = 0;
  }
  if( pShmNode->isReadonly && rc==SQLITE_OK ) rc = SQLITE_READONLY;
  sqlite3_mutex_leave(pShmNode->mutex);
  return rc;
}

/*
** Change the lock state for a shared-memory segment.
**

      if( pList==0 ){
        /* Must have at least one page for the WAL commit flag.
        ** Ticket [2d1a5c67dfc2363e44f29d9bbd57f] 2011-05-18 */
        rc = sqlite3PagerGet(pPager, 1, &pPageOne);
        pList = pPageOne;
        pList->pDirty = 0;
      }
      assert( rc==SQLITE_OK );
      if( ALWAYS(pList) ){
        rc = pagerWalFrames(pPager, pList, pPager->dbSize, 1, 
            (pPager->fullSync ? pPager->syncFlags : 0)
        );
      }
      sqlite3PagerUnref(pPageOne);
      if( rc==SQLITE_OK ){
        sqlite3PcacheCleanAll(pPager->pPCache);

    );
    pCache->pSynced = pPg;
    if( !pPg ){
      for(pPg=pCache->pDirtyTail; pPg && pPg->nRef; pPg=pPg->pDirtyPrev);
    }
    if( pPg ){
      int rc;
#ifdef SQLITE_LOG_CACHE_SPILL
      sqlite3_log(SQLITE_FULL, 
                  "spill page %d making room for %d - cache used: %d/%d",
                  pPg->pgno, pgno,
                  sqlite3GlobalConfig.pcache.xPagecount(pCache->pCache),
                  pCache->nMax);
#endif
      rc = pCache->xStress(pCache->pStress, pPg);
      if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
        return rc;
      }
    }

    pPage = sqlite3GlobalConfig.pcache.xFetch(pCache->pCache, pgno, 2);

#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))

/*
** CAPI3REF: Flags For File Open Operations
**
** These bit values are intended for use in the
** 3rd parameter to the [sqlite3_open_v2()] interface and
** in the 4th parameter to the [sqlite3_vfs.xOpen] method.

**
** Mutexes are created using [sqlite3_mutex_alloc()].
*/
typedef struct sqlite3_mutex sqlite3_mutex;

/*
** CAPI3REF: OS Interface Object

**
** An instance of the sqlite3_vfs object defines the interface between
** the SQLite core and the underlying operating system.  The "vfs"
** in the name of the object stands for "virtual file system".  See
** the [VFS | VFS documentation] for further information.
**
** The value of the iVersion field is initially 1 but may be larger in
** future versions of SQLite.  Additional fields may be appended to this
** object when the iVersion value is increased.  Note that the structure
** of the sqlite3_vfs object changes in the transaction between
** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not
** modified.

*/
struct VTable {
  sqlite3 *db;              /* Database connection associated with this table */
  Module *pMod;             /* Pointer to module implementation */
  sqlite3_vtab *pVtab;      /* Pointer to vtab instance */
  int nRef;                 /* Number of pointers to this structure */
  u8 bConstraint;           /* True if constraints are supported */
  int iSavepoint;           /* Depth of the SAVEPOINT stack */
  VTable *pNext;            /* Next in linked list (see above) */
};

/*
** Each SQL table is represented in memory by an instance of the
** following structure.
**

  u8 disableTriggers;  /* True to disable triggers */
  double nQueryLoop;   /* Estimated number of iterations of a query */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */

  int nzVar;           /* Number of available slots in azVar[] */
  char **azVar;        /* Pointers to names of parameters */
  Vdbe *pReprepare;    /* VM being reprepared (sqlite3Reprepare()) */
  int nAlias;          /* Number of aliased result set columns */
  int nAliasAlloc;     /* Number of allocated slots for aAlias[] */
  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */

    case SQLITE_IOERR_BLOCKED:       zName = "SQLITE_IOERR_BLOCKED";     break;
    case SQLITE_IOERR_NOMEM:         zName = "SQLITE_IOERR_NOMEM";       break;
    case SQLITE_IOERR_ACCESS:        zName = "SQLITE_IOERR_ACCESS";      break;
    case SQLITE_IOERR_CHECKRESERVEDLOCK:
                               zName = "SQLITE_IOERR_CHECKRESERVEDLOCK"; break;
    case SQLITE_IOERR_LOCK:          zName = "SQLITE_IOERR_LOCK";        break;
    case SQLITE_CORRUPT_VTAB:        zName = "SQLITE_CORRUPT_VTAB";      break;
    case SQLITE_READONLY_RECOVERY:   zName = "SQLITE_READONLY_RECOVERY"; break;
    case SQLITE_READONLY_CANTLOCK:   zName = "SQLITE_READONLY_CANTLOCK"; break;
    default:                         zName = "SQLITE_Unknown";           break;
  }
  return zName;
}
#define t1ErrorName sqlite3TestErrorName

/*

/*
** 2010 April 7
**
** 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 implements an example of a simple VFS implementation that 
** omits complex features often not required or not possible on embedded
** platforms.  Code is included to buffer writes to the journal file, 
** which can be a significant performance improvement on some embedded
** platforms.
**



** OVERVIEW
**
**   The code in this file implements a minimal SQLite VFS that can be 
**   used on Linux and other posix-like operating systems. The following 
**   system calls are used:
**
**    File-system: access(), unlink(), getcwd()

**
******************************************************************************
**
** This file contains code for a VFS layer that acts as a wrapper around
** an existing VFS. The code in this file attempts to verify that SQLite
** correctly populates and syncs a journal file before writing to a
** corresponding database file.
**






** INTERFACE
**
**   The public interface to this wrapper VFS is two functions:
**
**     jt_register()
**     jt_unregister()
**

**     a) A block of zeroes (or anything else that is not a valid 
**        journal-header) is written to the start of the journal file.
**
**     b) A journal file is truncated to zero bytes in size using xTruncate.
**
**     c) The journal file is deleted using xDelete.
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

/*
** Maximum pathname length supported by the jt backend.
*/
#define JT_MAX_PATHNAME 512

/*

/*
** 2010 October 28
**
** 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 - that breaks up a very large database file
** into two or more smaller files on disk.  This is useful, for example,
** in order to support large, multi-gigabyte databases on older filesystems
** that limit the maximum file size to 2 GiB.
**
** USAGE:
**
** Compile this source file and link it with your application.  Then
** at start-time, invoke the following procedure:
**
**   int sqlite3_multiplex_initialize(


**      const char *zOrigVfsName,    // The underlying real VFS
**      int makeDefault              // True to make multiplex the default VFS
**   );
**
** The procedure call above will create and register a new VFS shim named
** "multiplex".  The multiplex VFS will use the VFS named by zOrigVfsName to
** do the actual disk I/O.  (The zOrigVfsName parameter may be NULL, in 
** which case the default VFS at the moment sqlite3_multiplex_initialize()
** is called will be used as the underlying real VFS.)  
**
** If the makeDefault parameter is TRUE then multiplex becomes the new
** default VFS.  Otherwise, you can use the multiplex VFS by specifying
** "multiplex" as the 4th parameter to sqlite3_open_v2() or by employing
** URI filenames and adding "vfs=multiplex" as a parameter to the filename
** URI.
**
** The multiplex VFS allows databases up to 32 GiB in size.  But it splits
** the files up into 1 GiB pieces, so that they will work even on filesystems
** that do not support large files.
*/
#include "sqlite3.h"
#include <string.h>
#include <assert.h>
#include "test_multiplex.h"

#ifndef SQLITE_CORE

/*
** 2010 May 05
**
** 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 the implementation of the Tcl [testvfs] command,
** used to create SQLite VFS implementations with various properties and
** instrumentation to support testing SQLite.
**
**   testvfs VFSNAME ?OPTIONS?
**
** Available options are:
**
**   -noshm      BOOLEAN        (True to omit shm methods. Default false)
**   -default    BOOLEAN        (True to make the vfs default. Default false)
**   -szosfile   INTEGER        (Value for sqlite3_vfs.szOsFile)
**   -mxpathname INTEGER        (Value for sqlite3_vfs.mxPathname)
**   -iversion   INTEGER        (Value for sqlite3_vfs.iVersion)
*/
#if SQLITE_TEST          /* This file is used for testing only */

#include "sqlite3.h"
#include "sqliteInt.h"

typedef struct Testvfs Testvfs;
typedef struct TestvfsShm TestvfsShm;
typedef struct TestvfsBuffer TestvfsBuffer;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file contains code implements a VFS shim that writes diagnostic
** output for each VFS call, similar to "strace".
**
** USAGE:
**
** This source file exports a single symbol which is the name of a
** function:
**
**   int vfstrace_register(
**     const char *zTraceName,         // Name of the newly constructed VFS
**     const char *zOldVfsName,        // Name of the underlying VFS
**     int (*xOut)(const char*,void*), // Output routine.  ex: fputs
**     void *pOutArg,                  // 2nd argument to xOut.  ex: stderr
**     int makeDefault                 // Make the new VFS the default
**   );
**
** Applications that want to trace their VFS usage must provide a callback
** function with this prototype:
**
**   int traceOutput(const char *zMessage, void *pAppData);
**
** This function will "output" the trace messages, where "output" can
** mean different things to different applications.  The traceOutput function
** for the command-line shell (see shell.c) is "fputs" from the standard
** library, which means that all trace output is written on the stream
** specified by the second argument.  In the case of the command-line shell
** the second argument is stderr.  Other applications might choose to output
** trace information to a file, over a socket, or write it into a buffer.
**
** The vfstrace_register() function creates a new "shim" VFS named by
** the zTraceName parameter.  A "shim" VFS is an SQLite backend that does
** not really perform the duties of a true backend, but simply filters or
** interprets VFS calls before passing them off to another VFS which does
** the actual work.  In this case the other VFS - the one that does the
** real work - is identified by the second parameter, zOldVfsName.  If
** the the 2nd parameter is NULL then the default VFS is used.  The common
** case is for the 2nd parameter to be NULL.
**
** The third and fourth parameters are the pointer to the output function
** and the second argument to the output function.  For the SQLite
** command-line shell, when the -vfstrace option is used, these parameters
** are fputs and stderr, respectively.
**
** The fifth argument is true (non-zero) to cause the newly created VFS
** to become the default VFS.  The common case is for the fifth parameter
** to be true.
**
** The call to vfstrace_register() simply creates the shim VFS that does
** tracing.  The application must also arrange to use the new VFS for
** all database connections that are created and for which tracing is 
** desired.  This can be done by specifying the trace VFS using URI filename
** notation, or by specifying the trace VFS as the 4th parameter to
** sqlite3_open_v2() or by making the trace VFS be the default (by setting
** the 5th parameter of vfstrace_register() to 1).
**
**
** ENABLING VFSTRACE IN A COMMAND-LINE SHELL
**
** The SQLite command line shell implemented by the shell.c source file
** can be used with this module.  To compile in -vfstrace support, first
** gather this file (test_vfstrace.c), the shell source file (shell.c),
** and the SQLite amalgamation source files (sqlite3.c, sqlite3.h) into
** the working directory.  Then compile using a command like the following:
**
**    gcc -o sqlite3 -Os -I. -DSQLITE_ENABLE_VFSTRACE \
**        -DSQLITE_THREADSAFE=0 -DSQLITE_ENABLE_FTS3 -DSQLITE_ENABLE_RTREE \
**        -DHAVE_READLINE -DHAVE_USLEEP=1 \
**        shell.c test_vfstrace.c sqlite3.c -ldl -lreadline -lncurses
**
** The gcc command above works on Linux and provides (in addition to the
** -vfstrace option) support for FTS3 and FTS4, RTREE, and command-line
** editing using the readline library.  The command-line shell does not
** use threads so we added -DSQLITE_THREADSAFE=0 just to make the code
** run a little faster.   For compiling on a Mac, you'll probably need
** to omit the -DHAVE_READLINE, the -lreadline, and the -lncurses options.
** The compilation could be simplified to just this:
**
**    gcc -DSQLITE_ENABLE_VFSTRACE \
**         shell.c test_vfstrace.c sqlite3.c -ldl -lpthread
**
** In this second example, all unnecessary options have been removed
** Note that since the code is now threadsafe, we had to add the -lpthread
** option to pull in the pthreads library.
**
** To cross-compile for windows using MinGW, a command like this might
** work:
**
**    /opt/mingw/bin/i386-mingw32msvc-gcc -o sqlite3.exe -Os -I \
**         -DSQLITE_THREADSAFE=0 -DSQLITE_ENABLE_VFSTRACE \
**         shell.c test_vfstrace.c sqlite3.c
**
** Similar compiler commands will work on different systems.  The key
** invariants are (1) you must have -DSQLITE_ENABLE_VFSTRACE so that
** the shell.c source file will know to include the -vfstrace command-line
** option and (2) you must compile and link the three source files
** shell,c, test_vfstrace.c, and sqlite3.c.  
*/
#include <stdlib.h>
#include <string.h>
#include "sqlite3.h"

/*
** An instance of this structure is attached to the each trace VFS to

  if( pEngine==0 ){
    db->mallocFailed = 1;
    return SQLITE_NOMEM;
  }
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->nzVar==0 );

  assert( pParse->azVar==0 );
  enableLookaside = db->lookaside.bEnabled;
  if( db->lookaside.pStart ) db->lookaside.bEnabled = 1;
  while( !db->mallocFailed && zSql[i]!=0 ){
    assert( i>=0 );
    pParse->sLastToken.z = &zSql[i];
    pParse->sLastToken.n = sqlite3GetToken((unsigned char*)&zSql[i],&tokenType);
    i += pParse->sLastToken.n;

    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
    ** will take responsibility for freeing the Table structure.
    */
    sqlite3DeleteTable(db, pParse->pNewTable);
  }

  sqlite3DeleteTrigger(db, pParse->pNewTrigger);
  for(i=pParse->nzVar-1; i>=0; i--) sqlite3DbFree(db, pParse->azVar[i]);
  sqlite3DbFree(db, pParse->azVar);
  sqlite3DbFree(db, pParse->aAlias);
  while( pParse->pAinc ){
    AutoincInfo *p = pParse->pAinc;
    pParse->pAinc = p->pNext;
    sqlite3DbFree(db, p);
  }
  while( pParse->pZombieTab ){

** If the parameter is named, then its name appears in P4 and P3==1.
** The P4 value is used by sqlite3_bind_parameter_name().
*/
case OP_Variable: {            /* out2-prerelease */
  Mem *pVar;       /* Value being transferred */

  assert( pOp->p1>0 && pOp->p1<=p->nVar );
  assert( pOp->p4.z==0 || pOp->p4.z==p->azVar[pOp->p1-1] );
  pVar = &p->aVar[pOp->p1 - 1];
  if( sqlite3VdbeMemTooBig(pVar) ){
    goto too_big;
  }
  sqlite3VdbeMemShallowCopy(pOut, pVar, MEM_Static);
  UPDATE_MAX_BLOBSIZE(pOut);
  break;

  u16 flags1;         /* Copy of initial value of pIn1->flags */
  u16 flags3;         /* Copy of initial value of pIn3->flags */

  pIn1 = &aMem[pOp->p1];
  pIn3 = &aMem[pOp->p3];
  flags1 = pIn1->flags;
  flags3 = pIn3->flags;
  if( (flags1 | flags3)&MEM_Null ){
    /* One or both operands are NULL */
    if( pOp->p5 & SQLITE_NULLEQ ){
      /* If SQLITE_NULLEQ is set (which will only happen if the operator is
      ** OP_Eq or OP_Ne) then take the jump or not depending on whether
      ** or not both operands are null.
      */
      assert( pOp->opcode==OP_Eq || pOp->opcode==OP_Ne );
      res = (flags1 & flags3 & MEM_Null)==0;
    }else{
      /* SQLITE_NULLEQ is clear and at least one operand is NULL,
      ** then the result is always NULL.
      ** The jump is taken if the SQLITE_JUMPIFNULL bit is set.
      */
      if( pOp->p5 & SQLITE_STOREP2 ){
        pOut = &aMem[pOp->p2];

      */
      sqlite3SetString(&p->zErrMsg, db, "cannot open savepoint - "
        "SQL statements in progress");
      rc = SQLITE_BUSY;
    }else{
      nName = sqlite3Strlen30(zName);

#ifndef SQLITE_OMIT_VIRTUAL_TABLE
      /* This call is Ok even if this savepoint is actually a transaction
      ** savepoint (and therefore should not prompt xSavepoint()) callbacks.
      ** If this is a transaction savepoint being opened, it is guaranteed
      ** that the db->aVTrans[] array is empty.  */
      assert( db->autoCommit==0 || db->nVTrans==0 );
      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN,
                                db->nStatement+db->nSavepoint);
      if( rc!=SQLITE_OK ) goto abort_due_to_error;
#endif

      /* Create a new savepoint structure. */
      pNew = sqlite3DbMallocRaw(db, sizeof(Savepoint)+nName+1);
      if( pNew ){
        pNew->zName = (char *)&pNew[1];
        memcpy(pNew->zName, zName, nName+1);
    

      assert( sqlite3BtreeIsInTrans(pBt) );
      if( p->iStatement==0 ){
        assert( db->nStatement>=0 && db->nSavepoint>=0 );
        db->nStatement++; 
        p->iStatement = db->nSavepoint + db->nStatement;
      }

      rc = sqlite3VtabSavepoint(db, SAVEPOINT_BEGIN, p->iStatement-1);
      if( rc==SQLITE_OK ){
        rc = sqlite3BtreeBeginStmt(pBt, p->iStatement);
      }

      /* Store the current value of the database handles deferred constraint
      ** counter. If the statement transaction needs to be rolled back,
      ** the value of this counter needs to be restored too.  */

/* Opcode: Trace * * * P4 *
**
** If tracing is enabled (by the sqlite3_trace()) interface, then
** the UTF-8 string contained in P4 is emitted on the trace callback.
*/
case OP_Trace: {
  char *zTrace;
  char *z;

  if( db->xTrace && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0 ){


    z = sqlite3VdbeExpandSql(p, zTrace);
    db->xTrace(db->pTraceArg, z);
    sqlite3DbFree(db, z);
  }
#ifdef SQLITE_DEBUG
  if( (db->flags & SQLITE_SqlTrace)!=0
   && (zTrace = (pOp->p4.z ? pOp->p4.z : p->zSql))!=0
  ){
    sqlite3DebugPrintf("SQL-trace: %s\n", zTrace);
  }
#endif /* SQLITE_DEBUG */

  break;
}
#endif


/* Opcode: Noop * * * * *
**

void sqlite3VdbeChangeP4(Vdbe*, int addr, const char *zP4, int N);
void sqlite3VdbeUsesBtree(Vdbe*, int);
VdbeOp *sqlite3VdbeGetOp(Vdbe*, int);
int sqlite3VdbeMakeLabel(Vdbe*);
void sqlite3VdbeRunOnlyOnce(Vdbe*);
void sqlite3VdbeDelete(Vdbe*);
void sqlite3VdbeDeleteObject(sqlite3*,Vdbe*);
void sqlite3VdbeMakeReady(Vdbe*,Parse*);
int sqlite3VdbeFinalize(Vdbe*);
void sqlite3VdbeResolveLabel(Vdbe*, int);
int sqlite3VdbeCurrentAddr(Vdbe*);
#ifdef SQLITE_DEBUG
  int sqlite3VdbeAssertMayAbort(Vdbe *, int);
  void sqlite3VdbeTrace(Vdbe*,FILE*);
#endif
void sqlite3VdbeResetStepResult(Vdbe*);
void sqlite3VdbeRewind(Vdbe*);
int sqlite3VdbeReset(Vdbe*);
void sqlite3VdbeSetNumCols(Vdbe*,int);
int sqlite3VdbeSetColName(Vdbe*, int, int, const char *, void(*)(void*));
void sqlite3VdbeCountChanges(Vdbe*);
sqlite3 *sqlite3VdbeDb(Vdbe*);
void sqlite3VdbeSetSql(Vdbe*, const char *z, int n, int);
void sqlite3VdbeSwap(Vdbe*,Vdbe*);

  u32 magic;              /* Magic number for sanity checking */
  char *zErrMsg;          /* Error message written here */
  Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
  VdbeCursor **apCsr;     /* One element of this array for each open cursor */
  Mem *aVar;              /* Values for the OP_Variable opcode. */
  char **azVar;           /* Name of variables */
  ynVar nVar;             /* Number of entries in aVar[] */
  ynVar nzVar;            /* Number of entries in azVar[] */
  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
  int pc;                 /* The program counter */
  int rc;                 /* Value to return */
  u8 errorAction;         /* Recovery action to do in case of an error */

  u8 explain;             /* True if EXPLAIN present on SQL command */
  u8 changeCntOn;         /* True to update the change-counter */
  u8 expired;             /* True if the VM needs to be recompiled */
  u8 runOnlyOnce;         /* Automatically expire on reset */
  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
  u8 inVtabMethod;        /* See comments above */
  u8 usesStmtJournal;     /* True if uses a statement journal */

  }else{
    Vdbe *v = (Vdbe*)pStmt;
#ifdef SQLITE_ENABLE_SQLRR
    SRRecReset(pStmt);
#endif
    sqlite3_mutex_enter(v->db->mutex);
    rc = sqlite3VdbeReset(v);
    sqlite3VdbeRewind(v);
    assert( (rc & (v->db->errMask))==rc );
    rc = sqlite3ApiExit(v->db, rc);
    sqlite3_mutex_leave(v->db->mutex);
  }
  return rc;
}

** This routine is added to support DBD::SQLite.  
*/
int sqlite3_bind_parameter_count(sqlite3_stmt *pStmt){
  Vdbe *p = (Vdbe*)pStmt;
  return p ? p->nVar : 0;
}



























/*
** Return the name of a wildcard parameter.  Return NULL if the index
** is out of range or if the wildcard is unnamed.
**
** The result is always UTF-8.
*/
const char *sqlite3_bind_parameter_name(sqlite3_stmt *pStmt, int i){
  Vdbe *p = (Vdbe*)pStmt;
  if( p==0 || i<1 || i>p->nzVar ){
    return 0;
  }

  return p->azVar[i-1];
}

/*
** Given a wildcard parameter name, return the index of the variable
** with that name.  If there is no variable with the given name,
** return 0.
*/
int sqlite3VdbeParameterIndex(Vdbe *p, const char *zName, int nName){
  int i;
  if( p==0 ){
    return 0;
  }

  if( zName ){
    for(i=0; i<p->nzVar; i++){
      const char *z = p->azVar[i];
      if( z && memcmp(z,zName,nName)==0 && z[nName]==0 ){
        return i+1;
      }
    }
  }
  return 0;

  }else{
    *pnByte += nByte;
  }
  return pBuf;
}

/*


** Rewind the VDBE back to the beginning in preparation for

** running it.










*/
void sqlite3VdbeRewind(Vdbe *p){








#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
  int i;

#endif
  assert( p!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );

  /* There should be at least one opcode.
  */
  assert( p->nOp>0 );

  /* Set the magic to VDBE_MAGIC_RUN sooner rather than later. */
  p->magic = VDBE_MAGIC_RUN;

#ifdef SQLITE_DEBUG
  for(i=1; i<p->nMem; i++){
    assert( p->aMem[i].db==p->db );
  }
#endif
  p->pc = -1;
  p->rc = SQLITE_OK;
  p->errorAction = OE_Abort;
  p->magic = VDBE_MAGIC_RUN;
  p->nChange = 0;
  p->cacheCtr = 1;
  p->minWriteFileFormat = 255;
  p->iStatement = 0;
  p->nFkConstraint = 0;
#ifdef VDBE_PROFILE
  for(i=0; i<p->nOp; i++){
    p->aOp[i].cnt = 0;
    p->aOp[i].cycles = 0;
  }
#endif
}

/*
** Prepare a virtual machine for execution for the first time after
** creating the virtual machine.  This involves things such
** as allocating stack space and initializing the program counter.
** After the VDBE has be prepped, it can be executed by one or more
** calls to sqlite3VdbeExec().  
**
** This function may be called exact once on a each virtual machine.
** After this routine is called the VM has been "packaged" and is ready
** to run.  After this routine is called, futher calls to 
** sqlite3VdbeAddOp() functions are prohibited.  This routine disconnects
** the Vdbe from the Parse object that helped generate it so that the
** the Vdbe becomes an independent entity and the Parse object can be
** destroyed.
**
** Use the sqlite3VdbeRewind() procedure to restore a virtual machine back
** to its initial state after it has been run.
*/
void sqlite3VdbeMakeReady(
  Vdbe *p,                       /* The VDBE */
  Parse *pParse                  /* Parsing context */
){
  sqlite3 *db;                   /* The database connection */
  int nVar;                      /* Number of parameters */
  int nMem;                      /* Number of VM memory registers */
  int nCursor;                   /* Number of cursors required */
  int nArg;                      /* Number of arguments in subprograms */
  int n;                         /* Loop counter */
  u8 *zCsr;                      /* Memory available for allocation */
  u8 *zEnd;                      /* First byte past allocated memory */
  int nByte;                     /* How much extra memory is needed */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  db = p->db;
  assert( db->mallocFailed==0 );
  nVar = pParse->nVar;
  nMem = pParse->nMem;
  nCursor = pParse->nTab;
  nArg = pParse->nMaxArg;
  
  /* For each cursor required, also allocate a memory cell. Memory
  ** cells (nMem+1-nCursor)..nMem, inclusive, will never be used by
  ** the vdbe program. Instead they are used to allocate space for
  ** VdbeCursor/BtCursor structures. The blob of memory associated with 
  ** cursor 0 is stored in memory cell nMem. Memory cell (nMem-1)
  ** stores the blob of memory associated with cursor 1, etc.
  **
  ** See also: allocateCursor().
  */
  nMem += nCursor;

  /* Allocate space for memory registers, SQL variables, VDBE cursors and 
  ** an array to marshal SQL function arguments in.


  */

  zCsr = (u8*)&p->aOp[p->nOp];       /* Memory avaliable for allocation */
  zEnd = (u8*)&p->aOp[p->nOpAlloc];  /* First byte past end of zCsr[] */


  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain && nMem<10 ){
    nMem = 10;
  }
  memset(zCsr, 0, zEnd-zCsr);
  zCsr += (zCsr - (u8*)0)&7;
  assert( EIGHT_BYTE_ALIGNMENT(zCsr) );

  /* Memory for registers, parameters, cursor, etc, is allocated in two
  ** passes.  On the first pass, we try to reuse unused space at the 
  ** end of the opcode array.  If we are unable to satisfy all memory
  ** requirements by reusing the opcode array tail, then the second
  ** pass will fill in the rest using a fresh allocation.  
  **
  ** This two-pass approach that reuses as much memory as possible from
  ** the leftover space at the end of the opcode array can significantly
  ** reduce the amount of memory held by a prepared statement.
  */
  do {
    nByte = 0;
    p->aMem = allocSpace(p->aMem, nMem*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), &zCsr, zEnd, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), &zCsr, zEnd, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), &zCsr, zEnd, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          &zCsr, zEnd, &nByte);
    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    zEnd = &zCsr[nByte];
  }while( nByte && !db->mallocFailed );

  p->nCursor = (u16)nCursor;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){
      p->aVar[n].flags = MEM_Null;
      p->aVar[n].db = db;
    }
  }
  if( p->azVar ){
    p->nzVar = pParse->nzVar;
    memcpy(p->azVar, pParse->azVar, p->nzVar*sizeof(p->azVar[0]));
    memset(pParse->azVar, 0, pParse->nzVar*sizeof(pParse->azVar[0]));
  }
  if( p->aMem ){
    p->aMem--;                      /* aMem[] goes from 1..nMem */
    p->nMem = nMem;                 /*       not from 0..nMem-1 */
    for(n=1; n<=nMem; n++){
      p->aMem[n].flags = MEM_Null;
      p->aMem[n].db = db;
    }
  }










  p->explain = pParse->explain;








  sqlite3VdbeRewind(p);






}

/*
** Close a VDBE cursor and release all the resources that cursor 
** happens to hold.
*/
void sqlite3VdbeFreeCursor(Vdbe *p, VdbeCursor *pCx){

    }
  
    /* If eStatementOp is non-zero, then a statement transaction needs to
    ** be committed or rolled back. Call sqlite3VdbeCloseStatement() to
    ** do so. If this operation returns an error, and the current statement
    ** error code is SQLITE_OK or SQLITE_CONSTRAINT, then promote the
    ** current statement error code.





    */
    if( eStatementOp ){
      rc = sqlite3VdbeCloseStatement(p, eStatementOp);
      if( rc ){

        if( p->rc==SQLITE_OK || p->rc==SQLITE_CONSTRAINT ){
          p->rc = rc;
          sqlite3DbFree(db, p->zErrMsg);
          p->zErrMsg = 0;
        }
        invalidateCursorsOnModifiedBtrees(db);
        sqlite3RollbackAll(db);
        sqlite3CloseSavepoints(db);

** Free all memory associated with the Vdbe passed as the second argument.
** The difference between this function and sqlite3VdbeDelete() is that
** VdbeDelete() also unlinks the Vdbe from the list of VMs associated with
** the database connection.
*/
void sqlite3VdbeDeleteObject(sqlite3 *db, Vdbe *p){
  SubProgram *pSub, *pNext;
  int i;
  assert( p->db==0 || p->db==db );
  releaseMemArray(p->aVar, p->nVar);
  releaseMemArray(p->aColName, p->nResColumn*COLNAME_N);
  for(pSub=p->pProgram; pSub; pSub=pNext){
    pNext = pSub->pNext;
    vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
    sqlite3DbFree(db, pSub);
  }
  for(i=p->nzVar-1; i>=0; i--) sqlite3DbFree(db, p->azVar[i]);
  vdbeFreeOpArray(db, p->aOp, p->nOp);
  sqlite3DbFree(db, p->aLabel);
  sqlite3DbFree(db, p->aColName);
  sqlite3DbFree(db, p->zSql);
  sqlite3DbFree(db, p->pFree);
  sqlite3DbFree(db, p);
}

  u = 0;
  while( idx<szHdr && u<p->nField && d<=nKey ){
    u32 serial_type;

    idx += getVarint32(&aKey[idx], serial_type);
    pMem->enc = pKeyInfo->enc;
    pMem->db = pKeyInfo->db;
    /* pMem->flags = 0; // sqlite3VdbeSerialGet() will set this for us */
    pMem->zMalloc = 0;
    d += sqlite3VdbeSerialGet(&aKey[d], serial_type, pMem);
    pMem++;
    u++;
  }
  assert( u<=pKeyInfo->nField + 1 );
  p->nField = u;
  return (void*)p;
}

/*
** This routine destroys a UnpackedRecord object.
*/
void sqlite3VdbeDeleteUnpackedRecord(UnpackedRecord *p){
#ifdef SQLITE_DEBUG
  int i;
  Mem *pMem;

  assert( p!=0 );
  assert( p->flags & UNPACKED_NEED_DESTROY );
  for(i=0, pMem=p->aMem; i<p->nField; i++, pMem++){
    /* The unpacked record is always constructed by the
    ** sqlite3VdbeUnpackRecord() function above, which makes all
    ** strings and blobs static.  And none of the elements are
    ** ever transformed, so there is never anything to delete.
    */
    if( NEVER(pMem->zMalloc) ) sqlite3VdbeMemRelease(pMem);
  }
#endif
  if( p->flags & UNPACKED_NEED_FREE ){
    sqlite3DbFree(p->pKeyInfo->db, p);
  }
}

/*
** This function compares the two table rows or index records

      ** always return an SQL NULL. This is useful because it means
      ** we can invoke OP_Column to fill in the vdbe cursors type 
      ** and offset cache without causing any IO.
      */
      sqlite3VdbeChangeP4(v, 3+flags, SQLITE_INT_TO_PTR(pTab->nCol+1),P4_INT32);
      sqlite3VdbeChangeP2(v, 7, pTab->nCol);
      if( !db->mallocFailed ){
        pParse->nVar = 1;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }
   
    pBlob->flags = flags;
    pBlob->iCol = iCol;
    pBlob->db = db;
    sqlite3BtreeLeaveAll(db);

      sqlite3ErrorMsg(pParse, "%s", zErr);
    }
    sqlite3DbFree(db, zErr);
  }

  return rc;
}

/*
** Grow the db->aVTrans[] array so that there is room for at least one
** more v-table. Return SQLITE_NOMEM if a malloc fails, or SQLITE_OK otherwise.
*/
static int growVTrans(sqlite3 *db){
  const int ARRAY_INCR = 5;

  /* Grow the sqlite3.aVTrans array if required */
  if( (db->nVTrans%ARRAY_INCR)==0 ){
    VTable **aVTrans;
    int nBytes = sizeof(sqlite3_vtab *) * (db->nVTrans + ARRAY_INCR);
    aVTrans = sqlite3DbRealloc(db, (void *)db->aVTrans, nBytes);
    if( !aVTrans ){
      return SQLITE_NOMEM;
    }
    memset(&aVTrans[db->nVTrans], 0, sizeof(sqlite3_vtab *)*ARRAY_INCR);
    db->aVTrans = aVTrans;
  }

  return SQLITE_OK;
}

/*
** Add the virtual table pVTab to the array sqlite3.aVTrans[]. Space should
** have already been reserved using growVTrans().
*/
static void addToVTrans(sqlite3 *db, VTable *pVTab){
  /* Add pVtab to the end of sqlite3.aVTrans */
  db->aVTrans[db->nVTrans++] = pVTab;
  sqlite3VtabLock(pVTab);

}

/*
** This function is invoked by the vdbe to call the xCreate method
** of the virtual table named zTab in database iDb. 
**
** If an error occurs, *pzErr is set to point an an English language

  }else{
    rc = vtabCallConstructor(db, pTab, pMod, pMod->pModule->xCreate, pzErr);
  }

  /* Justification of ALWAYS():  The xConstructor method is required to
  ** create a valid sqlite3_vtab if it returns SQLITE_OK. */
  if( rc==SQLITE_OK && ALWAYS(sqlite3GetVTable(db, pTab)) ){
    rc = growVTrans(db);
    if( rc==SQLITE_OK ){
      addToVTrans(db, sqlite3GetVTable(db, pTab));
    }
  }

  return rc;
}

/*
** This function is used to set the schema of a virtual table.  It is only

      VTable *pVTab = db->aVTrans[i];
      sqlite3_vtab *p = pVTab->pVtab;
      if( p ){
        int (*x)(sqlite3_vtab *);
        x = *(int (**)(sqlite3_vtab *))((char *)p->pModule + offset);
        if( x ) x(p);
      }
      pVTab->iSavepoint = 0;
      sqlite3VtabUnlock(pVTab);
    }
    sqlite3DbFree(db, db->aVTrans);
    db->nVTrans = 0;
    db->aVTrans = 0;
  }
}

    /* If pVtab is already in the aVTrans array, return early */
    for(i=0; i<db->nVTrans; i++){
      if( db->aVTrans[i]==pVTab ){
        return SQLITE_OK;
      }
    }

    /* Invoke the xBegin method. If successful, add the vtab to the 
    ** sqlite3.aVTrans[] array. */
    rc = growVTrans(db);
    if( rc==SQLITE_OK ){
      rc = pModule->xBegin(pVTab->pVtab);
      if( rc==SQLITE_OK ){
        addToVTrans(db, pVTab);
      }
    }
  }
  return rc;
}

/*
** Invoke either the xSavepoint, xRollbackTo or xRelease method of all

** function immediately. If all calls to virtual table methods are successful,
** SQLITE_OK is returned.
*/
int sqlite3VtabSavepoint(sqlite3 *db, int op, int iSavepoint){
  int rc = SQLITE_OK;

  assert( op==SAVEPOINT_RELEASE||op==SAVEPOINT_ROLLBACK||op==SAVEPOINT_BEGIN );
  assert( iSavepoint>=0 );
  if( db->aVTrans ){
    int i;
    for(i=0; rc==SQLITE_OK && i<db->nVTrans; i++){
      VTable *pVTab = db->aVTrans[i];
      const sqlite3_module *pMod = pVTab->pMod->pModule;
      if( pMod->iVersion>=2 ){
        int (*xMethod)(sqlite3_vtab *, int);
        switch( op ){
          case SAVEPOINT_BEGIN:
            xMethod = pMod->xSavepoint;
            pVTab->iSavepoint = iSavepoint+1;
            break;
          case SAVEPOINT_ROLLBACK:
            xMethod = pMod->xRollbackTo;
            break;
          default:
            xMethod = pMod->xRelease;
            break;
        }
        if( xMethod && pVTab->iSavepoint>iSavepoint ){
          rc = xMethod(db->aVTrans[i]->pVtab, iSavepoint);
        }
      }
    }
  }
  return rc;
}

/*

  int nWiData;               /* Size of array apWiData */
  volatile u32 **apWiData;   /* Pointer to wal-index content in memory */
  u32 szPage;                /* Database page size */
  i16 readLock;              /* Which read lock is being held.  -1 for none */
  u8 exclusiveMode;          /* Non-zero if connection is in exclusive mode */
  u8 writeLock;              /* True if in a write transaction */
  u8 ckptLock;               /* True if holding a checkpoint lock */
  u8 readOnly;               /* WAL_RDWR, WAL_RDONLY, or WAL_SHM_RDONLY */
  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  const char *zWalName;      /* Name of WAL file */
  u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
#ifdef SQLITE_DEBUG
  u8 lockError;              /* True if a locking error has occurred */
#endif
};

/*
** Candidate values for Wal.exclusiveMode.
*/
#define WAL_NORMAL_MODE     0
#define WAL_EXCLUSIVE_MODE  1     
#define WAL_HEAPMEMORY_MODE 2

/*
** Possible values for WAL.readOnly
*/
#define WAL_RDWR        0    /* Normal read/write connection */
#define WAL_RDONLY      1    /* The WAL file is readonly */
#define WAL_SHM_RDONLY  2    /* The SHM file is readonly */

/*
** Each page of the wal-index mapping contains a hash-table made up of
** an array of HASHTABLE_NSLOT elements of the following type.
*/
typedef u16 ht_slot;

/*

    if( pWal->exclusiveMode==WAL_HEAPMEMORY_MODE ){
      pWal->apWiData[iPage] = (u32 volatile *)sqlite3MallocZero(WALINDEX_PGSZ);
      if( !pWal->apWiData[iPage] ) rc = SQLITE_NOMEM;
    }else{
      rc = sqlite3OsShmMap(pWal->pDbFd, iPage, WALINDEX_PGSZ, 
          pWal->writeLock, (void volatile **)&pWal->apWiData[iPage]
      );
      if( rc==SQLITE_READONLY ){
        pWal->readOnly |= WAL_SHM_RDONLY;
        rc = SQLITE_OK;
      }
    }
  }

  *ppPage = pWal->apWiData[iPage];
  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
  return rc;
}

  pRet->zWalName = zWalName;
  pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);

  /* Open file handle on the write-ahead log file. */
  flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
  rc = sqlite3OsOpen(pVfs, zWalName, pRet->pWalFd, flags, &flags);
  if( rc==SQLITE_OK && flags&SQLITE_OPEN_READONLY ){
    pRet->readOnly = WAL_RDONLY;
  }

  if( rc!=SQLITE_OK ){
    walIndexClose(pRet, 0);
    sqlite3OsClose(pRet->pWalFd);
    sqlite3_free(pRet);
  }else{

  */
  badHdr = (page0 ? walIndexTryHdr(pWal, pChanged) : 1);

  /* If the first attempt failed, it might have been due to a race
  ** with a writer.  So get a WRITE lock and try again.
  */
  assert( badHdr==0 || pWal->writeLock==0 );
  if( badHdr ){
    if( pWal->readOnly & WAL_SHM_RDONLY ){
      if( SQLITE_OK==(rc = walLockShared(pWal, WAL_WRITE_LOCK)) ){
        walUnlockShared(pWal, WAL_WRITE_LOCK);
        rc = SQLITE_READONLY_RECOVERY;
      }
    }else if( SQLITE_OK==(rc = walLockExclusive(pWal, WAL_WRITE_LOCK, 1)) ){
      pWal->writeLock = 1;
      if( SQLITE_OK==(rc = walIndexPage(pWal, 0, &page0)) ){
        badHdr = walIndexTryHdr(pWal, pChanged);
        if( badHdr ){
          /* If the wal-index header is still malformed even while holding
          ** a WRITE lock, it can only mean that the header is corrupted and
          ** needs to be reconstructed.  So run recovery to do exactly that.
          */
          rc = walIndexRecover(pWal);
          *pChanged = 1;
        }
      }
      pWal->writeLock = 0;
      walUnlockExclusive(pWal, WAL_WRITE_LOCK, 1);
    }
  }

  /* If the header is read successfully, check the version number to make
  ** sure the wal-index was not constructed with some future format that
  ** this version of SQLite cannot understand.
  */
  if( badHdr==0 && pWal->hdr.iVersion!=WALINDEX_MAX_VERSION ){

      assert( thisMark!=READMARK_NOT_USED );
      mxReadMark = thisMark;
      mxI = i;
    }
  }
  /* There was once an "if" here. The extra "{" is to preserve indentation. */
  {
    if( (pWal->readOnly & WAL_SHM_RDONLY)==0
     && (mxReadMark<pWal->hdr.mxFrame || mxI==0)
    ){
      for(i=1; i<WAL_NREADER; i++){
        rc = walLockExclusive(pWal, WAL_READ_LOCK(i), 1);
        if( rc==SQLITE_OK ){
          mxReadMark = pInfo->aReadMark[i] = pWal->hdr.mxFrame;
          mxI = i;
          walUnlockExclusive(pWal, WAL_READ_LOCK(i), 1);
          break;
        }else if( rc!=SQLITE_BUSY ){
          return rc;
        }
      }
    }
    if( mxI==0 ){
      assert( rc==SQLITE_BUSY );
      return rc==SQLITE_BUSY ? WAL_RETRY : SQLITE_READONLY_CANTLOCK;
    }

    rc = walLockShared(pWal, WAL_READ_LOCK(mxI));
    if( rc ){
      return rc==SQLITE_BUSY ? WAL_RETRY : rc;
    }
    /* Now that the read-lock has been obtained, check that neither the

        /* Limit the size of WAL file if the journal_size_limit PRAGMA is
        ** set to a non-negative value.  Log errors encountered
        ** during the truncation attempt. */
        if( pWal->mxWalSize>=0 ){
          i64 sz;
          int rx;
          sqlite3BeginBenignMalloc();
          rx = sqlite3OsFileSize(pWal->pWalFd, &sz);
          if( rx==SQLITE_OK && (sz > pWal->mxWalSize) ){
            rx = sqlite3OsTruncate(pWal->pWalFd, pWal->mxWalSize);
          }
          sqlite3EndBenignMalloc();
          if( rx ){
            sqlite3_log(rx, "cannot limit WAL size: %s", pWal->zWalName);
          }
        }

        pWal->nCkpt++;
        pWal->hdr.mxFrame = 0;

  int rc;                         /* Return code */
  int isChanged = 0;              /* True if a new wal-index header is loaded */
  int eMode2 = eMode;             /* Mode to pass to walCheckpoint() */

  assert( pWal->ckptLock==0 );
  assert( pWal->writeLock==0 );

  if( pWal->readOnly ) return SQLITE_READONLY;
  WALTRACE(("WAL%p: checkpoint begins\n", pWal));
  rc = walLockExclusive(pWal, WAL_CKPT_LOCK, 1);
  if( rc ){
    /* Usually this is SQLITE_BUSY meaning that another thread or process
    ** is already running a checkpoint, or maybe a recovery.  But it might
    ** also be SQLITE_IOERR. */
    return rc;

  set e
}

# EVIDENCE-OF: R-35840-33204 If URI filename interpretation is enabled,
# and the filename argument begins with "file:", then the filename is
# interpreted as a URI.
#
# EVIDENCE-OF: R-32637-34037 URI filename interpretation is enabled if
# the SQLITE_OPEN_URI flag is is set in the fourth argument to
# sqlite3_open_v2(), or if it has been enabled globally using the
# SQLITE_CONFIG_URI option with the sqlite3_config() method or by the
# SQLITE_USE_URI compile-time option.
#
if {$tcl_platform(platform) == "unix"} {
  set flags [list SQLITE_OPEN_READWRITE SQLITE_OPEN_CREATE]

  # Tests with SQLITE_CONFIG_URI configured to false. URI intepretation is
  # only enabled if the SQLITE_OPEN_URI flag is specified.
  sqlite3_shutdown

      set e [sqlite3_errmsg $DB]
      sqlite3_close $DB
      set e
    } $error
  }
}

# EVIDENCE-OF: R-45981-25528 The fragment component of a URI, if
# present, is ignored.
#
#   It is difficult to test that something is ignore correctly. So these tests
#   just show that adding a fragment does not interfere with the pathname or
#   parameters passed through to the VFS xOpen() methods.
#
if {$tcl_platform(platform) == "unix"} {
  foreach {tn uri parse} "
    1    {file:test.db#abc}     {[pwd]/test.db {}}
    2    {file:test.db?a=b#abc} {[pwd]/test.db {a b}}
    3    {file:test.db?a=b#?c=d} {[pwd]/test.db {a b}}
  " {
    do_test 3.$tn { parse_uri $uri } $parse
  }
}

# EVIDENCE-OF: R-62557-09390 SQLite uses the path component of the URI
# as the name of the disk file which contains the database.
#
# EVIDENCE-OF: R-28659-11035 If the path begins with a '/' character,
# then it is interpreted as an absolute path.
#
# EVIDENCE-OF: R-46234-61323 If the path does not begin with a '/'
# (meaning that the authority section is omitted from the URI) then the
# path is interpreted as a relative path.
#
if {$tcl_platform(platform) == "unix"} {
  foreach {tn uri parse} "
    1    {file:test.db}             {[pwd]/test.db {}}
    2    {file:/test.db}            {/test.db {}}
    3    {file:///test.db}          {/test.db {}}
    4    {file://localhost/test.db} {/test.db {}}

    proc csql1 {sql} { list [catch { sql1 $sql } msg] $msg }
    proc csql2 {sql} { list [catch { sql2 $sql } msg] $msg }
    proc csql3 {sql} { list [catch { sql3 $sql } msg] $msg }

    uplevel set $varname $tn
    uplevel $script

    catch { code2 { db2 close } }
    catch { code3 { db3 close } }
    catch { close $::code2_chan }
    catch { close $::code3_chan }
    catch { db close }
  }
}

# Launch another testfixture process to be controlled by this one. A

# been resolved.
#
# 
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix tkt-2d1a5c67d

ifcapable {!wal || !vtab} {finish_test; return}

for {set ii 1} {$ii<=10} {incr ii} {
  do_test tkt-2d1a5c67d.1.$ii {
    db close
    forcedelete test.db test.db-wal
    sqlite3 db test.db
    db eval "PRAGMA cache_size=$::ii"

      INSERT INTO t1(a,b) VALUES(1,2);
      SELECT sum(length(y)) FROM t2;
      COMMIT;
      SELECT * FROM t1;
    }
  } {1000000 1 2}
}

db close
sqlite3 db test.db


do_execsql_test 3.1 {
  PRAGMA cache_size = 10;
  CREATE TABLE t3(a INTEGER PRIMARY KEY, b);
  CREATE TABLE t4(a);
}

do_execsql_test 3.2 {
  INSERT INTO t3 VALUES(NULL, randomblob(500));
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 2
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 4
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 8
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 16
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 32
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 64
  INSERT INTO t3 SELECT NULL, b||b FROM t3;     -- 128
}

do_execsql_test 3.3 {
  BEGIN;
    INSERT INTO t4 VALUES('xyz');
}

do_test 3.4 {
  set blobs [list]
  for {set i 1} {$i<100} {incr i} {
    set b [db incrblob -readonly t3 b $i]
    read $b
    lappend blobs $b
  }

  execsql COMMIT
  execsql { SELECT * FROM t4 WHERE a = 'xyz' }
} {xyz}

do_test 3.5 {
  foreach b $blobs { close $b }
  execsql { SELECT * FROM t4 WHERE a = 'xyz' }
} {xyz}

# Check that recovery works on the WAL file.
#
forcedelete test.db2-wal test.db2
do_test 3.6 {
  file copy test.db-wal test.db2-wal
  file copy test.db test.db2
  sqlite3 db2 test.db2
  execsql { SELECT * FROM t4 WHERE a = 'xyz' } db2
} {xyz}

finish_test

  7      file:test.db?mork=1#boris            test.db
  8      file:test.db#boris                   test.db
  9      test.db#boris                        test.db#boris
  10     file:test%2Edb                       test.db
  11     file                                 file
  12     http:test.db                         http:test.db
  13     file:test.db%00extra                 test.db
  14     file:testdb%00.db%00extra            testdb

  15     test.db?mork=1#boris                 test.db?mork=1#boris
  16     file://localhostPWD/test.db%3Fhello  test.db?hello
} {
  
  if {$tcl_platform(platform)=="windows"} {
    if {$tn>14} break
    set uri  [string map [list PWD /[pwd]] $uri]
  } else {
    set uri  [string map [list PWD [pwd]] $uri]
  }

  if {[file isdir $file]} {error "$file is a directory"}
  forcedelete $file
  do_test 1.$tn.1 { file exists $file } 0
  set DB [sqlite3_open $uri]
  do_test 1.$tn.2 { file exists $file } 1
  sqlite3_close $DB
  forcedelete $file

}
foreach {tn uri kvlist} {
  1      file:test.db?hello=world                     {hello world}
  2      file:test.db?hello&world                     {hello {} world {}}
  3      file:test.db?hello=1&world=2&vfs=tvfs        {hello 1 world 2 vfs tvfs}
  4      file:test.db?hello=1&world=2&vfs=tvfs2        {}
  5      file:test.db?%68%65%6C%6C%6F=%77%6F%72%6C%64 {hello world}
  6      file:testdb%00.db?hello%00extra=world%00ex   {hello world}
  7      file:testdb%00.db?hello%00=world%00          {hello world}
  8      file:testdb%00.db?=world&xyz=abc             {xyz abc}
  9      file:test.db?%00hello=world&xyz=abc          {xyz abc}
  10     file:test.db?hello=%00world&xyz=             {hello {} xyz {}}
  11     file:test.db?=#ravada                        {}
  12     file:test.db?&&&&&&&&hello=world&&&&&&&      {hello world}

  13     test.db?&&&&&&&&hello=world&&&&&&&           {}
  14     http:test.db?hello&world                     {}

# 2011 May 09
#
# 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 tests for using WAL databases in read-only mode.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
set ::testprefix walro


do_multiclient_test tn {
  # These tests are only going to work on unix.
  #
  if {$tcl_platform(platform) != "unix"} continue

  # Do not run tests with the connections in the same process.
  #
  if {$tn==2} continue
  
  # Close all connections and delete the database.
  #
  code1 { db close  }
  code2 { db2 close }
  code3 { db3 close }
  forcedelete test.db
  forcedelete walro

  foreach c {code1 code2 code3} {
    $c {
      sqlite3_shutdown
      sqlite3_config_uri 1
    }
  }

  file mkdir walro

  do_test 1.1.1 {
    code2 { sqlite3 db2 test.db }
    sql2 { 
      PRAGMA journal_mode = WAL;
      CREATE TABLE t1(x, y);
      INSERT INTO t1 VALUES('a', 'b');
    }
    file exists test.db-shm
  } {1}

  do_test 1.1.2 {
    file attributes test.db-shm -permissions r--r--r--
    code1 { sqlite3 db file:test.db?readonly_shm=1 }
  } {}

  do_test 1.1.3 { sql1 "SELECT * FROM t1" }                {a b}
  do_test 1.1.4 { sql2 "INSERT INTO t1 VALUES('c', 'd')" } {}
  do_test 1.1.5 { sql1 "SELECT * FROM t1" }                {a b c d}

  # Check that the read-only connection cannot write or checkpoint the db.
  #
  do_test 1.1.6 { 
    csql1 "INSERT INTO t1 VALUES('e', 'f')" 
  } {1 {attempt to write a readonly database}}
  do_test 1.1.7 { 
    csql1 "PRAGMA wal_checkpoint"
  } {1 {attempt to write a readonly database}}

  do_test 1.1.9  { sql2 "INSERT INTO t1 VALUES('e', 'f')" } {}
  do_test 1.1.10 { sql1 "SELECT * FROM t1" }                {a b c d e f}

  do_test 1.1.11 { 
    sql2 {
      INSERT INTO t1 VALUES('g', 'h');
      PRAGMA wal_checkpoint;
    }
    set {} {}
  } {}
  do_test 1.1.12 { sql1 "SELECT * FROM t1" }                {a b c d e f g h}
  do_test 1.1.13  { sql2 "INSERT INTO t1 VALUES('i', 'j')" } {}

  do_test 1.2.1 {
    code2 { db2 close }
    code1 { db close }
    list [file exists test.db-wal] [file exists test.db-shm]
  } {1 1}
  do_test 1.2.2 {
    code1 { sqlite3 db file:test.db?readonly_shm=1 }
    sql1 { SELECT * FROM t1 }
  } {a b c d e f g h i j}

  do_test 1.2.3 {
    code1 { db close }
    file attributes test.db-shm -permissions rw-r--r--
    hexio_write test.db-shm 0 01020304 
    file attributes test.db-shm -permissions r--r--r--
    code1 { sqlite3 db file:test.db?readonly_shm=1 }
    csql1 { SELECT * FROM t1 }
  } {1 {attempt to write a readonly database}}
  do_test 1.2.4 {
    code1 { sqlite3_extended_errcode db } 
  } {SQLITE_READONLY_RECOVERY}

  do_test 1.2.5 {
    file attributes test.db-shm -permissions rw-r--r--
    code2 { sqlite3 db2 test.db }
    sql2 "SELECT * FROM t1" 
  } {a b c d e f g h i j}
  file attributes test.db-shm -permissions r--r--r--
  do_test 1.2.6 { sql1 "SELECT * FROM t1" } {a b c d e f g h i j}

  do_test 1.2.7 { 
    sql2 {
      PRAGMA wal_checkpoint;
      INSERT INTO t1 VALUES('k', 'l');
    }
    set {} {}
  } {}
  do_test 1.2.8 { sql1 "SELECT * FROM t1" } {a b c d e f g h i j k l}

  # Now check that if the readonly_shm option is not supplied, or if it
  # is set to zero, it is not possible to connect to the database without
  # read-write access to the shm.
  do_test 1.3.1 {
    code1 { db close }
    code1 { sqlite3 db test.db }
    csql1 { SELECT * FROM t1 }
  } {1 {unable to open database file}}

  # Also test that if the -shm file can be opened for read/write access,
  # it is, even if readonly_shm=1 is present in the URI.
  do_test 1.3.2.1 {
    code1 { db close }
    code2 { db2 close }
    file exists test.db-shm
  } {0}
  do_test 1.3.2.2 {
    code1 { sqlite3 db file:test.db?readonly_shm=1 }
    sql1 { SELECT * FROM t1 }
  } {a b c d e f g h i j k l}
  do_test 1.3.2.3 {
    code1 { db close }
    close [open test.db-shm w]
    file attributes test.db-shm -permissions r--r--r--
    code1 { sqlite3 db file:test.db?readonly_shm=1 }
    csql1 { SELECT * FROM t1 }
  } {1 {attempt to write a readonly database}}
  do_test 1.3.2.4 {
    code1 { sqlite3_extended_errcode db } 
  } {SQLITE_READONLY_RECOVERY}
}

finish_test