SQLite

                  $(TOP)/test/tt3_checkpoint.c \
                  $(TOP)/test/tt3_index.c      \
                  $(TOP)/test/tt3_vacuum.c      \
                  $(TOP)/test/tt3_stress.c      \
                  $(TOP)/test/tt3_lookaside1.c

threadtest3$(TEXE): sqlite3.lo $(THREADTEST3_SRC)
	$(LTLINK) $(TOP)/test/threadtest3.c $(TOP)/src/test_multiplex.c sqlite3.lo -o $@ $(TLIBS)

threadtest: threadtest3$(TEXE)
	./threadtest3$(TEXE)

releasetest:	
	$(TCLSH_CMD) $(TOP)/test/releasetest.tcl

THREADTEST3_SRC = $(TOP)/test/threadtest3.c    \
                  $(TOP)/test/tt3_checkpoint.c \
                  $(TOP)/test/tt3_index.c      \
                  $(TOP)/test/tt3_vacuum.c      \
                  $(TOP)/test/tt3_stress.c      \
                  $(TOP)/test/tt3_lookaside1.c

threadtest3$(EXE): sqlite3.o $(THREADTEST3_SRC) $(TOP)/src/test_multiplex.c
	$(TCCX) $(TOP)/test/threadtest3.c $(TOP)/src/test_multiplex.c sqlite3.o -o $@ $(THREADLIB)

threadtest: threadtest3$(EXE)
	./threadtest3$(EXE)

TEST_EXTENSION = $(SHPREFIX)testloadext.$(SO)
$(TEST_EXTENSION): $(TOP)/src/test_loadext.c
	$(MKSHLIB) $(TOP)/src/test_loadext.c -o $(TEST_EXTENSION)

      ** was either part of sibling page iOld (possibly an overflow cell), 
      ** or else the divider cell to the left of sibling page iOld. So,
      ** if sibling page iOld had the same page number as pNew, and if
      ** pCell really was a part of sibling page iOld (not a divider or
      ** overflow cell), we can skip updating the pointer map entries.  */
      if( iOld>=nNew
       || pNew->pgno!=aPgno[iOld]

       || !SQLITE_WITHIN(pCell,aOld,&aOld[usableSize])
      ){
        if( !leafCorrection ){
          ptrmapPut(pBt, get4byte(pCell), PTRMAP_BTREE, pNew->pgno, &rc);
        }
        if( cachedCellSize(&b,i)>pNew->minLocal ){
          ptrmapPutOvflPtr(pNew, pCell, &rc);
        }

  "DEFAULT_MMAP_SIZE=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_SIZE),
#endif
#if SQLITE_DISABLE_DIRSYNC
  "DISABLE_DIRSYNC",
#endif
#if SQLITE_DISABLE_LFS
  "DISABLE_LFS",
#endif
#if SQLITE_ENABLE_8_3_NAMES
  "ENABLE_8_3_NAMES",
#endif
#if SQLITE_ENABLE_API_ARMOR
  "ENABLE_API_ARMOR",
#endif
#if SQLITE_ENABLE_ATOMIC_WRITE
  "ENABLE_ATOMIC_WRITE",
#endif

** to store the copy of expression p, the copies of p->u.zToken
** (if applicable), and the copies of the p->pLeft and p->pRight expressions,
** if any. Before returning, *pzBuffer is set to the first byte past the
** portion of the buffer copied into by this function.
*/
static Expr *exprDup(sqlite3 *db, Expr *p, int flags, u8 **pzBuffer){
  Expr *pNew = 0;                      /* Value to return */
  assert( flags==0 || flags==EXPRDUP_REDUCE );
  if( p ){
    const int isReduced = (flags&EXPRDUP_REDUCE);
    u8 *zAlloc;
    u32 staticFlag = 0;

    assert( pzBuffer==0 || isReduced );

      }
      if( isReduced ){
        assert( ExprHasProperty(p, EP_Reduced)==0 );
        memcpy(zAlloc, p, nNewSize);
      }else{
        int nSize = exprStructSize(p);
        memcpy(zAlloc, p, nSize);
        if( nSize<EXPR_FULLSIZE ){ 
          memset(&zAlloc[nSize], 0, EXPR_FULLSIZE-nSize);
        }
      }

      /* Set the EP_Reduced, EP_TokenOnly, and EP_Static flags appropriately. */
      pNew->flags &= ~(EP_Reduced|EP_TokenOnly|EP_Static|EP_MemToken);
      pNew->flags |= nStructSize & (EP_Reduced|EP_TokenOnly);
      pNew->flags |= staticFlag;

**
** The flags parameter contains a combination of the EXPRDUP_XXX flags.
** If the EXPRDUP_REDUCE flag is set, then the structure returned is a
** truncated version of the usual Expr structure that will be stored as
** part of the in-memory representation of the database schema.
*/
Expr *sqlite3ExprDup(sqlite3 *db, Expr *p, int flags){
  assert( flags==0 || flags==EXPRDUP_REDUCE );
  return exprDup(db, p, flags, 0);
}
ExprList *sqlite3ExprListDup(sqlite3 *db, ExprList *p, int flags){
  ExprList *pNew;
  struct ExprList_item *pItem, *pOldItem;
  int i;
  if( p==0 ) return 0;

  /* Version 3.8.11 and later */
  (sqlite3_value*(*)(const sqlite3_value*))sqlite3_value_dup,
  sqlite3_value_free,
  sqlite3_result_zeroblob64,
  sqlite3_bind_zeroblob64,
  /* Version 3.9.0 and later */
  sqlite3_value_subtype,
  sqlite3_result_subtype,
  /* Version 3.10.0 and later */
  sqlite3_status64,
  sqlite3_strlike,
  sqlite3_db_cacheflush
};

/*
** Attempt to load an SQLite extension library contained in the file
** zFile.  The entry point is zProc.  zProc may be 0 in which case a
** default entry point name (sqlite3_extension_init) is used.  Use
** of the default name is recommended.

      ** allocation (sz), and the maximum number of scratch allocations (N). */
      sqlite3GlobalConfig.pScratch = va_arg(ap, void*);
      sqlite3GlobalConfig.szScratch = va_arg(ap, int);
      sqlite3GlobalConfig.nScratch = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_PAGECACHE: {
      /* EVIDENCE-OF: R-18761-36601 There are three arguments to
      ** SQLITE_CONFIG_PAGECACHE: A pointer to 8-byte aligned memory (pMem),
      ** the size of each page cache line (sz), and the number of cache lines
      ** (N). */
      sqlite3GlobalConfig.pPage = va_arg(ap, void*);
      sqlite3GlobalConfig.szPage = va_arg(ap, int);
      sqlite3GlobalConfig.nPage = va_arg(ap, int);
      break;
    }
    case SQLITE_CONFIG_PCACHE_HDRSZ: {
      /* EVIDENCE-OF: R-39100-27317 The SQLITE_CONFIG_PCACHE_HDRSZ option takes

    (void)SQLITE_MISUSE_BKPT;
    return -1;
  }
#endif
  pBt = sqlite3DbNameToBtree(db, zDbName);
  return pBt ? sqlite3BtreeIsReadonly(pBt) : -1;
}

#if (SQLITE_ENABLE_APPLE_SPI>0) && defined(__APPLE__)

#include "sqlite3_private.h"

/* 
** Testing a file path for sqlite locks held by a process ID. 
** Returns SQLITE_LOCKSTATE_ON if locks are present on path

  if( NULL!=db ){ 
    sqlite3_close(db); /* need to close even if open returns an error */
  }
  return SQLITE_LOCKSTATE_ERROR;
}

#endif /* SQLITE_ENABLE_APPLE_SPI */

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** Obtain a snapshot handle for the snapshot of database zDb currently 
** being read by handle db.
*/
int sqlite3_snapshot_get(
  sqlite3 *db, 
  const char *zDb,
  sqlite3_snapshot **ppSnapshot
){
  int rc = SQLITE_ERROR;
#ifndef SQLITE_OMIT_WAL
  int iDb;

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);

  iDb = sqlite3FindDbName(db, zDb);
  if( iDb==0 || iDb>1 ){
    Btree *pBt = db->aDb[iDb].pBt;
    if( 0==sqlite3BtreeIsInTrans(pBt) ){
      rc = sqlite3BtreeBeginTrans(pBt, 0);
      if( rc==SQLITE_OK ){
        rc = sqlite3PagerSnapshotGet(sqlite3BtreePager(pBt), ppSnapshot);
      }
    }
  }

  sqlite3_mutex_leave(db->mutex);
#endif   /* SQLITE_OMIT_WAL */
  return rc;
}

/*
** Open a read-transaction on the snapshot idendified by pSnapshot.
*/
int sqlite3_snapshot_open(
  sqlite3 *db, 
  const char *zDb, 
  sqlite3_snapshot *pSnapshot
){
  int rc = SQLITE_ERROR;
#ifndef SQLITE_OMIT_WAL

#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  sqlite3_mutex_enter(db->mutex);
  if( db->autoCommit==0 ){
    int iDb;
    iDb = sqlite3FindDbName(db, zDb);
    if( iDb==0 || iDb>1 ){
      Btree *pBt = db->aDb[iDb].pBt;
      if( 0==sqlite3BtreeIsInReadTrans(pBt) ){
        rc = sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), pSnapshot);
        if( rc==SQLITE_OK ){
          rc = sqlite3BtreeBeginTrans(pBt, 0);
          sqlite3PagerSnapshotOpen(sqlite3BtreePager(pBt), 0);
        }
      }
    }
  }

  sqlite3_mutex_leave(db->mutex);
#endif   /* SQLITE_OMIT_WAL */
  return rc;
}

/*
** Free a snapshot handle obtained from sqlite3_snapshot_get().
*/
void sqlite3_snapshot_free(sqlite3_snapshot *pSnapshot){
  sqlite3_free(pSnapshot);
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

    ** is outstanding at one time.  (This is only checked in the
    ** single-threaded case since checking in the multi-threaded case
    ** would be much more complicated.) */
    assert( scratchAllocOut>=1 && scratchAllocOut<=2 );
    scratchAllocOut--;
#endif

    if( SQLITE_WITHIN(p, sqlite3GlobalConfig.pScratch, mem0.pScratchEnd) ){
      /* Release memory from the SQLITE_CONFIG_SCRATCH allocation */
      ScratchFreeslot *pSlot;
      pSlot = (ScratchFreeslot*)p;
      sqlite3_mutex_enter(mem0.mutex);
      pSlot->pNext = mem0.pScratchFree;
      mem0.pScratchFree = pSlot;
      mem0.nScratchFree++;

}

/*
** TRUE if p is a lookaside memory allocation from db
*/
#ifndef SQLITE_OMIT_LOOKASIDE
static int isLookaside(sqlite3 *db, void *p){
  return SQLITE_WITHIN(p, db->lookaside.pStart, db->lookaside.pEnd);
}
#else
#define isLookaside(A,B) 0
#endif

/*
** Return the size of a memory allocation previously obtained from

*/
static int openDirectory(const char *zFilename, int *pFd){
  int ii;
  int fd = -1;
  char zDirname[MAX_PATHNAME+1];

  sqlite3_snprintf(MAX_PATHNAME, zDirname, "%s", zFilename);
  for(ii=(int)strlen(zDirname); ii>0 && zDirname[ii]!='/'; ii--);
  if( ii>0 ){
    zDirname[ii] = '\0';
  }else{
    if( zDirname[0]!='/' ) zDirname[0] = '.';
    zDirname[1] = 0;
  }
  fd = robust_open(zDirname, O_RDONLY|O_BINARY, 0);
  if( fd>=0 ){
    OSTRACE(("OPENDIR %-3d %s\n", fd, zDirname));

  }
  *pFd = fd;
  if( fd>=0 ) return SQLITE_OK;
  return unixLogError(SQLITE_CANTOPEN_BKPT, "openDirectory", zDirname);
}

/*

    **   "<path to db>-journalNN"
    **   "<path to db>-walNN"
    **
    ** where NN is a decimal number. The NN naming schemes are 
    ** used by the test_multiplex.c module.
    */
    nDb = sqlite3Strlen30(zPath) - 1; 
    while( zPath[nDb]!='-' ){
#ifndef SQLITE_ENABLE_8_3_NAMES
      /* In the normal case (8+3 filenames disabled) the journal filename
      ** is guaranteed to contain a '-' character. */
      assert( nDb>0 );
      assert( sqlite3Isalnum(zPath[nDb]) );

#else
      /* If 8+3 names are possible, then the journal file might not contain
      ** a '-' character.  So check for that case and return early. */
      if( nDb==0 || zPath[nDb]=='.' ) return SQLITE_OK;


#endif
      nDb--;
    }

    memcpy(zDb, zPath, nDb);
    zDb[nDb] = '\0';

    if( 0==osStat(zDb, &sStat) ){
      *pMode = sStat.st_mode & 0777;
      *pUid = sStat.st_uid;
      *pGid = sStat.st_gid;

        if( rc==SQLITE_IOERR_DELETE_NOENT ) rc = SQLITE_OK;
      }
    }
  }
  return rc;
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** If this is a WAL database, obtain a snapshot handle for the snapshot
** currently open. Otherwise, return an error.
*/
int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot){
  int rc = SQLITE_ERROR;
  if( pPager->pWal ){
    rc = sqlite3WalSnapshotGet(pPager->pWal, ppSnapshot);
  }
  return rc;
}

/*
** If this is a WAL database, store a pointer to pSnapshot. Next time a
** read transaction is opened, attempt to read from the snapshot it 
** identifies. If this is not a WAL database, return an error.
*/
int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot){
  int rc = SQLITE_OK;
  if( pPager->pWal ){
    sqlite3WalSnapshotOpen(pPager->pWal, pSnapshot);
  }else{
    rc = SQLITE_ERROR;
  }
  return rc;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */
#endif /* !SQLITE_OMIT_WAL */

#ifdef SQLITE_ENABLE_ZIPVFS
/*
** A read-lock must be held on the pager when this function is called. If
** the pager is in WAL mode and the WAL file currently contains one or more
** frames, return the size in bytes of the page images stored within the

#ifndef SQLITE_OMIT_WAL
  int sqlite3PagerCheckpoint(Pager *pPager, int, int*, int*);
  int sqlite3PagerWalSupported(Pager *pPager);
  int sqlite3PagerWalCallback(Pager *pPager);
  int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
  int sqlite3PagerCloseWal(Pager *pPager);
# ifdef SQLITE_ENABLE_SNAPSHOT
  int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot);
  int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot);
# endif
#endif

#ifdef SQLITE_ENABLE_ZIPVFS
  int sqlite3PagerWalFramesize(Pager *pPager);
#endif

/* Functions used to query pager state and configuration. */

    return 0;
  }
  if( p->mxAlloc==0 ){
    N = p->nAlloc - p->nChar - 1;
    setStrAccumError(p, STRACCUM_TOOBIG);
    return N;
  }else{
    char *zOld = p->bMalloced ? p->zText : 0;
    i64 szNew = p->nChar;
    assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
    szNew += N + 1;
    if( szNew+p->nChar<=p->mxAlloc ){
      /* Force exponential buffer size growth as long as it does not overflow,
      ** to avoid having to call this routine too often */
      szNew += p->nChar;
    }
    if( szNew > p->mxAlloc ){
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_TOOBIG);
      return 0;
    }else{
      p->nAlloc = (int)szNew;
    }
    if( p->db ){
      zNew = sqlite3DbRealloc(p->db, zOld, p->nAlloc);
    }else{
      zNew = sqlite3_realloc64(zOld, p->nAlloc);
    }
    if( zNew ){
      assert( p->zText!=0 || p->nChar==0 );
      if( !p->bMalloced && p->nChar>0 ) memcpy(zNew, p->zText, p->nChar);
      p->zText = zNew;
      p->nAlloc = sqlite3DbMallocSize(p->db, zNew);
      p->bMalloced = 1;
    }else{
      sqlite3StrAccumReset(p);
      setStrAccumError(p, STRACCUM_NOMEM);
      return 0;
    }
  }
  return N;
}

/*
** Append N copies of character c to the given string buffer.
*/
void sqlite3AppendChar(StrAccum *p, int N, char c){
  testcase( p->nChar + (i64)N > 0x7fffffff );
  if( p->nChar+(i64)N >= p->nAlloc && (N = sqlite3StrAccumEnlarge(p, N))<=0 ){
    return;
  }
  assert( (p->zText==p->zBase)==(p->bMalloced==0) );
  while( (N--)>0 ) p->zText[p->nChar++] = c;
}

/*
** The StrAccum "p" is not large enough to accept N new bytes of z[].
** So enlarge if first, then do the append.
**
** This is a helper routine to sqlite3StrAccumAppend() that does special-case
** work (enlarging the buffer) using tail recursion, so that the
** sqlite3StrAccumAppend() routine can use fast calling semantics.
*/
static void SQLITE_NOINLINE enlargeAndAppend(StrAccum *p, const char *z, int N){
  N = sqlite3StrAccumEnlarge(p, N);
  if( N>0 ){
    memcpy(&p->zText[p->nChar], z, N);
    p->nChar += N;
  }
  assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
}

/*
** Append N bytes of text from z to the StrAccum object.  Increase the
** size of the memory allocation for StrAccum if necessary.
*/
void sqlite3StrAccumAppend(StrAccum *p, const char *z, int N){

/*
** Finish off a string by making sure it is zero-terminated.
** Return a pointer to the resulting string.  Return a NULL
** pointer if any kind of error was encountered.
*/
char *sqlite3StrAccumFinish(StrAccum *p){
  if( p->zText ){
    assert( (p->zText==p->zBase)==(p->bMalloced==0) );
    p->zText[p->nChar] = 0;
    if( p->mxAlloc>0 && p->bMalloced==0 ){
      p->zText = sqlite3DbMallocRaw(p->db, p->nChar+1 );
      if( p->zText ){
        memcpy(p->zText, p->zBase, p->nChar+1);
        p->bMalloced = 1;
      }else{
        setStrAccumError(p, STRACCUM_NOMEM);
      }
    }
  }
  return p->zText;
}

/*
** Reset an StrAccum string.  Reclaim all malloced memory.
*/
void sqlite3StrAccumReset(StrAccum *p){
  assert( (p->zText==0 || p->zText==p->zBase)==(p->bMalloced==0) );
  if( p->bMalloced ){
    sqlite3DbFree(p->db, p->zText);
    p->bMalloced = 0;
  }
  p->zText = 0;
}

/*
** Initialize a string accumulator.
**

void sqlite3StrAccumInit(StrAccum *p, sqlite3 *db, char *zBase, int n, int mx){
  p->zText = p->zBase = zBase;
  p->db = db;
  p->nChar = 0;
  p->nAlloc = n;
  p->mxAlloc = mx;
  p->accError = 0;
  p->bMalloced = 0;
}

/*
** Print into memory obtained from sqliteMalloc().  Use the internal
** %-conversion extensions.
*/
char *sqlite3VMPrintf(sqlite3 *db, const char *zFormat, va_list ap){

              iCol = -1;
            }
            break;
          }
        }
        if( iCol>=pTab->nCol && sqlite3IsRowid(zCol) && VisibleRowid(pTab) ){
          /* IMP: R-51414-32910 */

          iCol = -1;
        }
        if( iCol<pTab->nCol ){
          cnt++;
          if( iCol<0 ){
            pExpr->affinity = SQLITE_AFF_INTEGER;
          }else if( pExpr->iTable==0 ){

     && cntTab==1
     && pMatch
     && (pNC->ncFlags & NC_IdxExpr)==0
     && sqlite3IsRowid(zCol)
     && VisibleRowid(pMatch->pTab)
    ){
      cnt = 1;
      pExpr->iColumn = -1;
      pExpr->affinity = SQLITE_AFF_INTEGER;
    }

    /*
    ** If the input is of the form Z (not Y.Z or X.Y.Z) then the name Z
    ** might refer to an result-set alias.  This happens, for example, when
    ** we are resolving names in the WHERE clause of the following command:

#ifndef SQLITE_OMIT_EXPLAIN
  /* If this is an EXPLAIN, skip this step */
  if( pParse->explain ){
    return;
  }
#endif

  if( pParse->colNamesSet || db->mallocFailed ) return;
  assert( v!=0 );
  assert( pTabList!=0 );

  pParse->colNamesSet = 1;
  fullNames = (db->flags & SQLITE_FullColNames)!=0;
  shortNames = (db->flags & SQLITE_ShortColNames)!=0;
  sqlite3VdbeSetNumCols(v, pEList->nExpr);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    p = pEList->a[i].pExpr;

typedef struct ShellState ShellState;
struct ShellState {
  sqlite3 *db;           /* The database */
  int echoOn;            /* True to echo input commands */
  int autoEQP;           /* Run EXPLAIN QUERY PLAN prior to seach SQL stmt */
  int statsOn;           /* True to display memory stats before each finalize */
  int scanstatsOn;       /* True to display scan stats before each finalize */
  int countChanges;      /* True to display change counts */
  int backslashOn;       /* Resolve C-style \x escapes in SQL input text */
  int outCount;          /* Revert to stdout when reaching zero */
  int cnt;               /* Number of records displayed so far */
  FILE *out;             /* Write results here */
  FILE *traceOut;        /* Output for sqlite3_trace() */
  int nErr;              /* Number of errors seen */
  int mode;              /* An output mode setting */

/*
** Text of a help message
*/
static char zHelp[] =
  ".backup ?DB? FILE      Backup DB (default \"main\") to FILE\n"
  ".bail on|off           Stop after hitting an error.  Default OFF\n"
  ".binary on|off         Turn binary output on or off.  Default OFF\n"
  ".changes on|off        Show number of rows changed by SQL\n"
  ".clone NEWDB           Clone data into NEWDB from the existing database\n"
  ".databases             List names and files of attached databases\n"
  ".dbinfo ?DB?           Show status information about the database\n"
  ".dump ?TABLE? ...      Dump the database in an SQL text format\n"
  "                         If TABLE specified, only dump tables matching\n"
  "                         LIKE pattern TABLE.\n"
  ".echo on|off           Turn command echo on or off\n"

  /* The undocumented ".breakpoint" command causes a call to the no-op
  ** routine named test_breakpoint().
  */
  if( c=='b' && n>=3 && strncmp(azArg[0], "breakpoint", n)==0 ){
    test_breakpoint();
  }else

  if( c=='c' && n>=3 && strncmp(azArg[0], "changes", n)==0 ){
    if( nArg==2 ){
      p->countChanges = booleanValue(azArg[1]);
    }else{
      fprintf(stderr, "Usage: .changes on|off\n");
      rc = 1;
    }
  }else

  if( c=='c' && strncmp(azArg[0], "clone", n)==0 ){
    if( nArg==2 ){
      tryToClone(p, azArg[1]);
    }else{
      fprintf(stderr, "Usage: .clone FILENAME\n");
      rc = 1;

          fprintf(stderr, "%s %s\n", zPrefix, zErrMsg);
          sqlite3_free(zErrMsg);
          zErrMsg = 0;
        }else{
          fprintf(stderr, "%s %s\n", zPrefix, sqlite3_errmsg(p->db));
        }
        errCnt++;
      }else if( p->countChanges ){
        fprintf(p->out, "changes: %3d   total_changes: %d\n",
                sqlite3_changes(p->db), sqlite3_total_changes(p->db));
      }
      nSql = 0;
      if( p->outCount ){
        output_reset(p);
        p->outCount = 0;
      }
    }else if( nSql && _all_whitespace(zSql) ){

** is intended for diagnostic use only.
**
** <li>[[SQLITE_FCNTL_VFS_POINTER]]
** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
** [VFSes] currently in use.  ^(The argument X in
** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
** of type "[sqlite3_vfs] **".  This opcodes will set *X
** to a pointer to the top-level VFS.)^
** ^When there are multiple VFS shims in the stack, this opcode finds the
** upper-most shim only.
**
** <li>[[SQLITE_FCNTL_PRAGMA]]
** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 
** file control is sent to the open [sqlite3_file] object corresponding
** to the database file to which the pragma statement refers. ^The argument

** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
** memory allocation fails.
**
** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
** then sqlite3_value_free(V) is a harmless no-op.
*/
sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
void sqlite3_value_free(sqlite3_value*);

/*
** CAPI3REF: Obtain Aggregate Function Context
** METHOD: sqlite3_context
**
** Implementations of aggregate SQL functions use this
** routine to allocate memory for storing their state.

** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
*/
void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);

/*
** CAPI3REF: Flush caches to disk mid-transaction
**
** ^If a write-transaction is open on [database connection] D when the
** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
** pages in the pager-cache that are not currently in use are written out 
** to disk. A dirty page may be in use if a database cursor created by an
** active SQL statement is reading from it, or if it is page 1 of a database
** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
** interface flushes caches for all schemas - "main", "temp", and
** any [attached] databases.
**
** ^If this function needs to obtain extra database locks before dirty pages 
** can be flushed to disk, it does so. ^If those locks cannot be obtained 
** immediately and there is a busy-handler callback configured, it is invoked
** in the usual manner. ^If the required lock still cannot be obtained, then
** the database is skipped and an attempt made to flush any dirty pages
** belonging to the next (if any) database. ^If any databases are skipped
** because locks cannot be obtained, but no other error occurs, this
** function returns SQLITE_BUSY.
**
** ^If any other error occurs while flushing dirty pages to disk (for
** example an IO error or out-of-memory condition), then processing is
** abandoned and an SQLite [error code] is returned to the caller immediately.
**
** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
**
** ^This function does not set the database handle error code or message
** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
*/
int sqlite3_db_cacheflush(sqlite3*);

/*
** CAPI3REF: Database Snapshot
** KEYWORDS: {snapshot}
** EXPERIMENTAL
**
** An instance of the snapshot object records the state of a [WAL mode]
** database for some specific point in history.
**
** In [WAL mode], multiple [database connections] that are open on the
** same database file can each be reading a different historical version
** of the database file.  When a [database connection] begins a read
** transaction, that connection sees an unchanging copy of the database
** as it existed for the point in time when the transaction first started.
** Subsequent changes to the database from other connections are not seen
** by the reader until a new read transaction is started.
**
** The sqlite3_snapshot object records state information about an historical
** version of the database file so that it is possible to later open a new read
** transaction that sees that historical version of the database rather than
** the most recent version.
**
** The constructor for this object is [sqlite3_snapshot_get()].  The
** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
** to an historical snapshot (if possible).  The destructor for 
** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
*/
typedef struct sqlite3_snapshot sqlite3_snapshot;

/*
** CAPI3REF: Record A Database Snapshot
** EXPERIMENTAL
**
** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
** new [sqlite3_snapshot] object that records the current state of
** schema S in database connection D.  ^On success, the
** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
** ^If schema S of [database connection] D is not a [WAL mode] database
** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)]
** leaves the *P value unchanged and returns an appropriate [error code].
**
** The [sqlite3_snapshot] object returned from a successful call to
** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
** to avoid a memory leak.
**
** The [sqlite3_snapshot_get()] interface is only available when the
** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
*/
SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
  sqlite3 *db,
  const char *zSchema,
  sqlite3_snapshot **ppSnapshot
);

/*
** CAPI3REF: Start a read transaction on an historical snapshot
** EXPERIMENTAL
**
** ^The [sqlite3_snapshot_open(D,S,P)] interface attempts to move the
** read transaction that is currently open on schema S of
** [database connection] D so that it refers to historical [snapshot] P.
** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
** or an appropriate [error code] if it fails.
**
** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
** the first operation, apart from other sqlite3_snapshot_open() calls,
** following the [BEGIN] that starts a new read transaction.
** ^A [snapshot] will fail to open if it has been overwritten by a 
** [checkpoint].  
**
** The [sqlite3_snapshot_open()] interface is only available when the
** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
*/
SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
  sqlite3 *db,
  const char *zSchema,
  sqlite3_snapshot *pSnapshot
);

/*
** CAPI3REF: Destroy a snapshot
** EXPERIMENTAL
**
** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
** The application must eventually free every [sqlite3_snapshot] object
** using this routine to avoid a memory leak.
**
** The [sqlite3_snapshot_free()] interface is only available when the
** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
*/
SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);

/*
** Undo the hack that converts floating point types to integer for
** builds on processors without floating point support.
*/
#ifdef SQLITE_OMIT_FLOATING_POINT
# undef double
#endif

#ifdef __cplusplus
}  /* End of the 'extern "C"' block */
#endif
#endif /* _SQLITE3_H_ */

  void (*value_free)(sqlite3_value*);
  int (*result_zeroblob64)(sqlite3_context*,sqlite3_uint64);
  int (*bind_zeroblob64)(sqlite3_stmt*, int, sqlite3_uint64);
  /* Version 3.9.0 and later */
  unsigned int (*value_subtype)(sqlite3_value*);
  void (*result_subtype)(sqlite3_context*,unsigned int);
  /* Version 3.10.0 and later */
  int (*status64)(int,sqlite3_int64*,sqlite3_int64*,int);
  int (*strlike)(const char*,const char*,unsigned int);
  int (*db_cacheflush)(sqlite3*);
};

/*
** The following macros redefine the API routines so that they are
** redirected through the global sqlite3_api structure.
**
** This header file is also used by the loadext.c source file

#define sqlite3_value_free             sqlite3_api->value_free
#define sqlite3_result_zeroblob64      sqlite3_api->result_zeroblob64
#define sqlite3_bind_zeroblob64        sqlite3_api->bind_zeroblob64
/* Version 3.9.0 and later */
#define sqlite3_value_subtype          sqlite3_api->value_subtype
#define sqlite3_result_subtype         sqlite3_api->result_subtype
/* Version 3.10.0 and later */
#define sqlite3_status64               sqlite3_api->status64
#define sqlite3_strlike                sqlite3_api->strlike
#define sqlite3_db_cacheflush          sqlite3_api->db_cacheflush
#endif /* !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION) */

#if !defined(SQLITE_CORE) && !defined(SQLITE_OMIT_LOAD_EXTENSION)
  /* This case when the file really is being compiled as a loadable 
  ** extension */
# define SQLITE_EXTENSION_INIT1     const sqlite3_api_routines *sqlite3_api=0;
# define SQLITE_EXTENSION_INIT2(v)  sqlite3_api=v;

# define SQLITE_INT_TO_PTR(X)  ((void*)(intptr_t)(X))
# define SQLITE_PTR_TO_INT(X)  ((int)(intptr_t)(X))
#else                          /* Generates a warning - but it always works */
# define SQLITE_INT_TO_PTR(X)  ((void*)(X))
# define SQLITE_PTR_TO_INT(X)  ((int)(X))
#endif

/*
** The SQLITE_WITHIN(P,S,E) macro checks to see if pointer P points to
** something between S (inclusive) and E (exclusive).
**
** In other words, S is a buffer and E is a pointer to the first byte after
** the end of buffer S.  This macro returns true if P points to something
** contained within the buffer S.
*/
#if defined(HAVE_STDINT_H)
# define SQLITE_WITHIN(P,S,E) \
    ((uintptr_t)(P)>=(uintptr_t)(S) && (uintptr_t)(P)<(uintptr_t)(E))
#else
# define SQLITE_WITHIN(P,S,E) ((P)>=(S) && (P)<(E))
#endif

/*
** A macro to hint to the compiler that a function should not be
** inlined.
*/
#if defined(__GNUC__)
#  define SQLITE_NOINLINE  __attribute__((noinline))
#elif defined(_MSC_VER) && _MSC_VER>=1310

  sqlite3 *db;         /* Optional database for lookaside.  Can be NULL */
  char *zBase;         /* A base allocation.  Not from malloc. */
  char *zText;         /* The string collected so far */
  int  nChar;          /* Length of the string so far */
  int  nAlloc;         /* Amount of space allocated in zText */
  int  mxAlloc;        /* Maximum allowed allocation.  0 for no malloc usage */
  u8   accError;       /* STRACCUM_NOMEM or STRACCUM_TOOBIG */
  u8   bMalloced;      /* zText points to allocated space */
};
#define STRACCUM_NOMEM   1
#define STRACCUM_TOOBIG  2

/*
** A pointer to this structure is used to communicate information
** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.

    return TCL_ERROR;
  }
  pVfs->xCurrentTimeInt64(pVfs, &t);
  Tcl_SetObjResult(interp, Tcl_NewWideIntObj(t));
  return TCL_OK;
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** Usage: sqlite3_snapshot_get DB DBNAME
*/
static int test_snapshot_get(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;
  sqlite3 *db;
  char *zName;
  sqlite3_snapshot *pSnapshot = 0;

  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB DBNAME");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zName = Tcl_GetString(objv[2]);

  rc = sqlite3_snapshot_get(db, zName, &pSnapshot);
  if( rc!=SQLITE_OK ){
    Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
    return TCL_ERROR;
  }else{
    char zBuf[100];
    if( sqlite3TestMakePointerStr(interp, zBuf, pSnapshot) ) return TCL_ERROR;
    Tcl_SetObjResult(interp, Tcl_NewStringObj(zBuf, -1));
  }
  return TCL_OK;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** Usage: sqlite3_snapshot_open DB DBNAME SNAPSHOT
*/
static int test_snapshot_open(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;
  sqlite3 *db;
  char *zName;
  sqlite3_snapshot *pSnapshot;

  if( objc!=4 ){
    Tcl_WrongNumArgs(interp, 1, objv, "DB DBNAME SNAPSHOT");
    return TCL_ERROR;
  }
  if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;
  zName = Tcl_GetString(objv[2]);
  pSnapshot = (sqlite3_snapshot*)sqlite3TestTextToPtr(Tcl_GetString(objv[3]));

  rc = sqlite3_snapshot_open(db, zName, pSnapshot);
  if( rc!=SQLITE_OK ){
    Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
    return TCL_ERROR;
  }
  return TCL_OK;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

#ifdef SQLITE_ENABLE_SNAPSHOT
/*
** Usage: sqlite3_snapshot_free SNAPSHOT
*/
static int test_snapshot_free(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_snapshot *pSnapshot;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SNAPSHOT");
    return TCL_ERROR;
  }
  pSnapshot = (sqlite3_snapshot*)sqlite3TestTextToPtr(Tcl_GetString(objv[1]));
  sqlite3_snapshot_free(pSnapshot);
  return TCL_OK;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

/*
** Usage:  sqlite3_next_stmt  DB  STMT
**
** Return the next statment in sequence after STMT.
*/
static int test_next_stmt(
  void * clientData,

    Tcl_WrongNumArgs(interp, 1, objv, "SCRIPT");
    return TCL_ERROR;
  }
  if( logcallback.pObj ){
    Tcl_DecrRefCount(logcallback.pObj);
    logcallback.pObj = 0;
    logcallback.pInterp = 0;
    sqlite3_config(SQLITE_CONFIG_LOG, (void*)0, (void*)0);
  }
  if( objc>1 ){
    logcallback.pObj = objv[1];
    Tcl_IncrRefCount(logcallback.pObj);
    logcallback.pInterp = interp;
    sqlite3_config(SQLITE_CONFIG_LOG, xLogcallback, (void*)0);
  }
  return TCL_OK;
}

/*
**     tcl_objproc COMMANDNAME ARGS...
**

     { "sqlite3_stmt_scanstatus",       test_stmt_scanstatus,   0 },
     { "sqlite3_stmt_scanstatus_reset", test_stmt_scanstatus_reset,   0 },
#endif
#ifdef SQLITE_ENABLE_SQLLOG
     { "sqlite3_config_sqllog",         test_config_sqllog,   0 },
#endif
     { "vfs_current_time_int64",           vfsCurrentTimeInt64,   0 },
#ifdef SQLITE_ENABLE_SNAPSHOT
     { "sqlite3_snapshot_get", test_snapshot_get, 0 },
     { "sqlite3_snapshot_open", test_snapshot_open, 0 },
     { "sqlite3_snapshot_free", test_snapshot_free, 0 },
#endif
  };
  static int bitmask_size = sizeof(Bitmask)*8;
  static int longdouble_size = sizeof(LONGDOUBLE_TYPE);
  int i;
  extern int sqlite3_sync_count, sqlite3_fullsync_count;
  extern int sqlite3_opentemp_count;
  extern int sqlite3_like_count;

#endif

#ifdef SQLITE_ENABLE_MEMSYS5
  Tcl_SetVar2(interp, "sqlite_options", "mem5", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "mem5", "0", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_ENABLE_SNAPSHOT
  Tcl_SetVar2(interp, "sqlite_options", "snapshot", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "snapshot", "0", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_MUTEX_OMIT
  Tcl_SetVar2(interp, "sqlite_options", "mutex", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "mutex", "1", TCL_GLOBAL_ONLY);
#endif

/*
** xOpen implementation.
**
** Open a new fsdir cursor.
*/
static int fsdirOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
  FsdirCsr *pCur;
  /* Allocate an extra 256 bytes because it is undefined how big dirent.d_name
  ** is and we need enough space.  Linux provides plenty already, but
  ** Solaris only provides one byte. */
  pCur = (FsdirCsr*)sqlite3_malloc(sizeof(FsdirCsr)+256);
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(FsdirCsr));
  *ppCursor = &pCur->base;
  return SQLITE_OK;
}

/*

    ** a zeroed allocator then calling GETMALLOC. */
    memset(&m2, 0, sizeof(m2));
    sqlite3_config(SQLITE_CONFIG_MALLOC, &m2);
    sqlite3_config(SQLITE_CONFIG_GETMALLOC, &m2);
    assert( memcmp(&m2, &memfault.m, sizeof(m2))==0 );

    rc = sqlite3_config(SQLITE_CONFIG_MALLOC, &memfault.m);
    sqlite3_test_control(SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS,
        (void*)0, (void*)0);
  }

  if( rc==SQLITE_OK ){
    memfault.isInstalled = 1;
  }
  return rc;
}

  sqlite3_io_methods sIoMethodsV2;

  /* True when this shim has been initialized.
  */
  int isInitialized;

  /* For run-time access any of the other global data structures in this
  ** shim, the following mutex must be held. In practice, all this mutex
  ** protects is add/remove operations to/from the linked list of group objects
  ** starting at pGroups below. More specifically, it protects the value of
  ** pGroups itself, and the pNext/pPrev fields of each multiplexGroup
  ** structure.  */
  sqlite3_mutex *pMutex;

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

  void *pBuf,
  int iAmt,
  sqlite3_int64 iOfst
){
  multiplexConn *p = (multiplexConn*)pConn;
  multiplexGroup *pGroup = p->pGroup;
  int rc = SQLITE_OK;


  if( !pGroup->bEnabled ){
    sqlite3_file *pSubOpen = multiplexSubOpen(pGroup, 0, &rc, NULL, 0);

    if( pSubOpen==0 ){
      rc = SQLITE_IOERR_READ;
    }else{
      rc = pSubOpen->pMethods->xRead(pSubOpen, pBuf, iAmt, iOfst);
    }
  }else{
    while( iAmt > 0 ){
      int i = (int)(iOfst / pGroup->szChunk);
      sqlite3_file *pSubOpen;

      pSubOpen = multiplexSubOpen(pGroup, i, &rc, NULL, 1);

      if( pSubOpen ){
        int extra = ((int)(iOfst % pGroup->szChunk) + iAmt) - pGroup->szChunk;
        if( extra<0 ) extra = 0;
        iAmt -= extra;
        rc = pSubOpen->pMethods->xRead(pSubOpen, pBuf, iAmt,
                                       iOfst % pGroup->szChunk);
        if( rc!=SQLITE_OK ) break;
        pBuf = (char *)pBuf + iAmt;
        iOfst += iAmt;
        iAmt = extra;
      }else{
        rc = SQLITE_IOERR_READ;
        break;
      }
    }
  }


  return rc;
}

/* Pass xWrite requests thru to the original VFS after
** determining the correct chunk to operate on.
** Break up writes across chunk boundaries.
*/
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;

  if( !pGroup->bEnabled ){
    sqlite3_file *pSubOpen = multiplexSubOpen(pGroup, 0, &rc, NULL, 0);
    if( pSubOpen==0 ){
      rc = SQLITE_IOERR_WRITE;
    }else{
      rc = pSubOpen->pMethods->xWrite(pSubOpen, pBuf, iAmt, iOfst);
    }

                                        iOfst % pGroup->szChunk);
        pBuf = (char *)pBuf + iAmt;
        iOfst += iAmt;
        iAmt = extra;
      }
    }
  }

  return rc;
}

/* Pass xTruncate requests thru to the original VFS after
** determining the correct chunk to operate on.  Delete any
** chunks above the truncate mark.
*/

  }
#endif

  /* Generate code to destroy the database record of the trigger.
  */
  assert( pTable!=0 );
  if( (v = sqlite3GetVdbe(pParse))!=0 ){
    sqlite3NestedParse(pParse,












       "DELETE FROM %Q.%s WHERE name=%Q AND type='trigger'",



       db->aDb[iDb].zName, SCHEMA_TABLE(iDb), pTrigger->zName

    );
    sqlite3ChangeCookie(pParse, iDb);

    sqlite3VdbeAddOp4(v, OP_DropTrigger, iDb, 0, 0, pTrigger->zName, 0);



  }
}

/*
** Remove a trigger from the hash tables of the sqlite* pointer.
*/
void sqlite3UnlinkAndDeleteTrigger(sqlite3 *db, int iDb, const char *zName){

  if( (i & (i-1))==0 ){
    p->aLabel = sqlite3DbReallocOrFree(p->db, p->aLabel, 
                                       (i*2+1)*sizeof(p->aLabel[0]));
  }
  if( p->aLabel ){
    p->aLabel[i] = -1;
  }
  return ADDR(i);
}

/*
** Resolve label "x" to be the address of the next instruction to
** be inserted.  The parameter "x" must have been obtained from
** a prior call to sqlite3VdbeMakeLabel().
*/
void sqlite3VdbeResolveLabel(Vdbe *v, int x){
  Parse *p = v->pParse;
  int j = ADDR(x);
  assert( v->magic==VDBE_MAGIC_INIT );
  assert( j<p->nLabel );
  assert( j>=0 );
  if( p->aLabel ){
    p->aLabel[j] = v->nOp;
  }
  p->iFixedOp = v->nOp - 1;

        pOp->p4type = P4_ADVANCE;
        break;
      }
    }

    pOp->opflags = sqlite3OpcodeProperty[opcode];
    if( (pOp->opflags & OPFLG_JUMP)!=0 && pOp->p2<0 ){
      assert( ADDR(pOp->p2)<pParse->nLabel );
      pOp->p2 = aLabel[ADDR(pOp->p2)];
    }
  }
  sqlite3DbFree(p->db, pParse->aLabel);
  pParse->aLabel = 0;
  pParse->nLabel = 0;
  *pMaxFuncArgs = nMaxArgs;
  assert( p->bIsReader!=0 || DbMaskAllZero(p->btreeMask) );

  assert( p->magic==VDBE_MAGIC_INIT );
  if( p->nOp + nOp > p->pParse->nOpAlloc && growOpArray(p, nOp) ){
    return 0;
  }
  addr = p->nOp;
  pOut = &p->aOp[addr];
  for(i=0; i<nOp; i++, aOp++, pOut++){

    pOut->opcode = aOp->opcode;
    pOut->p1 = aOp->p1;


    pOut->p2 = aOp->p2;

    assert( aOp->p2>=0 );

    pOut->p3 = aOp->p3;
    pOut->p4type = P4_NOTUSED;
    pOut->p4.p = 0;
    pOut->p5 = 0;
#ifdef SQLITE_ENABLE_EXPLAIN_COMMENTS
    pOut->zComment = 0;
#endif

** NULL, it means that memory space has already been allocated and that
** this routine should not allocate any new memory.  When pBuf is not
** NULL simply return pBuf.  Only allocate new memory space when pBuf
** is NULL.
**
** nByte is the number of bytes of space needed.
**

** pFrom points to *pnFrom bytes of available space.  New space is allocated
** from the end of the pFrom buffer and *pnFrom is decremented.
**
** *pnNeeded is a counter of the number of bytes of space that have failed
** to allocate.  If there is insufficient space in pFrom to satisfy the
** request, then increment *pnNeeded by the amount of the request.
*/
static void *allocSpace(
  void *pBuf,          /* Where return pointer will be stored */
  int nByte,           /* Number of bytes to allocate */
  u8 *pFrom,           /* Memory available for allocation */
  int *pnFrom,         /* IN/OUT: Space available at pFrom */

  int *pnNeeded        /* If allocation cannot be made, increment *pnByte */
){
  assert( EIGHT_BYTE_ALIGNMENT(pFrom) );
  if( pBuf==0 ){
    nByte = ROUND8(nByte);
    if( nByte <= *pnFrom ){

      *pnFrom -= nByte;
      pBuf = &pFrom[*pnFrom];
    }else{
      *pnNeeded += nByte;
    }
  }
  assert( EIGHT_BYTE_ALIGNMENT(pBuf) );
  return pBuf;
}

/*
** Rewind the VDBE back to the beginning in preparation for
** running it.
*/

  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 nOnce;                     /* Number of OP_Once instructions */
  int n;                         /* Loop counter */
  int nFree;                     /* Available free space */
  u8 *zCsr;                      /* Memory available for allocation */

  int nByte;                     /* How much extra memory is needed */

  assert( p!=0 );
  assert( p->nOp>0 );
  assert( pParse!=0 );
  assert( p->magic==VDBE_MAGIC_INIT );
  assert( pParse==p->pParse );

  */
  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 */
  assert( pParse->nOpAlloc*sizeof(Op) <= 0x7fffff00 );
  nFree = (pParse->nOpAlloc - p->nOp)*sizeof(p->aOp[0]); /* Available space */

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

  p->expired = 0;
  
  /* 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, &nFree, &nByte);
    p->aVar = allocSpace(p->aVar, nVar*sizeof(Mem), zCsr, &nFree, &nByte);
    p->apArg = allocSpace(p->apArg, nArg*sizeof(Mem*), zCsr, &nFree, &nByte);
    p->azVar = allocSpace(p->azVar, nVar*sizeof(char*), zCsr, &nFree, &nByte);
    p->apCsr = allocSpace(p->apCsr, nCursor*sizeof(VdbeCursor*),
                          zCsr, &nFree, &nByte);
    p->aOnceFlag = allocSpace(p->aOnceFlag, nOnce, zCsr, &nFree, &nByte);
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
    p->anExec = allocSpace(p->anExec, p->nOp*sizeof(i64), zCsr, &nFree, &nByte);
#endif
    if( nByte ){
      p->pFree = sqlite3DbMallocZero(db, nByte);
    }
    zCsr = p->pFree;
    nFree = nByte;
  }while( nByte && !db->mallocFailed );

  p->nCursor = nCursor;
  p->nOnceFlag = nOnce;
  if( p->aVar ){
    p->nVar = (ynVar)nVar;
    for(n=0; n<nVar; n++){

  }

  /* String or blob */
  if( serial_type>=12 ){
    assert( pMem->n + ((pMem->flags & MEM_Zero)?pMem->u.nZero:0)
             == (int)sqlite3VdbeSerialTypeLen(serial_type) );
    len = pMem->n;
    if( len>0 ) memcpy(buf, pMem->z, len);
    return len;
  }

  /* NULL or constants 0 or 1 */
  return 0;
}

** returns SQLITE_CANTOPEN.
*/
#define WAL_MAX_VERSION      3007000
#define WALINDEX_MAX_VERSION 3007000

/*
** Indices of various locking bytes.   WAL_NREADER is the number
** of available reader locks and should be at least 3.  The default
** is SQLITE_SHM_NLOCK==8 and  WAL_NREADER==5.
*/
#define WAL_WRITE_LOCK         0
#define WAL_ALL_BUT_WRITE      1
#define WAL_CKPT_LOCK          1
#define WAL_RECOVER_LOCK       2
#define WAL_READ_LOCK(I)       (3+(I))
#define WAL_NREADER            (SQLITE_SHM_NLOCK-3)


/* Object declarations */
typedef struct WalIndexHdr WalIndexHdr;
typedef struct WalIterator WalIterator;
typedef struct WalCkptInfo WalCkptInfo;


/*
** The following object holds a copy of the wal-index header content.
**
** The actual header in the wal-index consists of two copies of this
** object followed by one instance of the WalCkptInfo object.
** For all versions of SQLite through 3.10.0 and probably beyond,
** the locking bytes (WalCkptInfo.aLock) start at offset 120 and
** the total header size is 136 bytes.
**
** The szPage value can be any power of 2 between 512 and 32768, inclusive.
** Or it can be 1 to represent a 65536-byte page.  The latter case was
** added in 3.7.1 when support for 64K pages was added.  
*/
struct WalIndexHdr {
  u32 iVersion;                   /* Wal-index version */

** nBackfill is the number of frames in the WAL that have been written
** back into the database. (We call the act of moving content from WAL to
** database "backfilling".)  The nBackfill number is never greater than
** WalIndexHdr.mxFrame.  nBackfill can only be increased by threads
** holding the WAL_CKPT_LOCK lock (which includes a recovery thread).
** However, a WAL_WRITE_LOCK thread can move the value of nBackfill from
** mxFrame back to zero when the WAL is reset.
**
** nBackfillAttempted is the largest value of nBackfill that a checkpoint
** has attempted to achieve.  Normally nBackfill==nBackfillAtempted, however
** the nBackfillAttempted is set before any backfilling is done and the
** nBackfill is only set after all backfilling completes.  So if a checkpoint
** crashes, nBackfillAttempted might be larger than nBackfill.  The
** WalIndexHdr.mxFrame must never be less than nBackfillAttempted.
**
** The aLock[] field is a set of bytes used for locking.  These bytes should
** never be read or written.
**
** There is one entry in aReadMark[] for each reader lock.  If a reader
** holds read-lock K, then the value in aReadMark[K] is no greater than
** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
** for any aReadMark[] means that entry is unused.  aReadMark[0] is 
** a special case; its value is never used and it exists as a place-holder
** to avoid having to offset aReadMark[] indexs by one.  Readers holding

**
** We assume that 32-bit loads are atomic and so no locks are needed in
** order to read from any aReadMark[] entries.
*/
struct WalCkptInfo {
  u32 nBackfill;                  /* Number of WAL frames backfilled into DB */
  u32 aReadMark[WAL_NREADER];     /* Reader marks */
  u8 aLock[SQLITE_SHM_NLOCK];     /* Reserved space for locks */
  u32 nBackfillAttempted;         /* WAL frames perhaps written, or maybe not */
  u32 notUsed0;                   /* Available for future enhancements */
};
#define READMARK_NOT_USED  0xffffffff


/* A block of WALINDEX_LOCK_RESERVED bytes beginning at
** WALINDEX_LOCK_OFFSET is reserved for locks. Since some systems
** only support mandatory file-locks, we do not read or write data
** from the region of the file on which locks are applied.
*/

#define WALINDEX_LOCK_OFFSET (sizeof(WalIndexHdr)*2+offsetof(WalCkptInfo,aLock))
#define WALINDEX_HDR_SIZE    (sizeof(WalIndexHdr)*2+sizeof(WalCkptInfo))

/* Size of header before each frame in wal */
#define WAL_FRAME_HDRSIZE 24

/* Size of write ahead log header, including checksum. */
/* #define WAL_HDRSIZE 24 */
#define WAL_HDRSIZE 32

  WalIndexHdr hdr;           /* Wal-index header for current transaction */
  u32 minFrame;              /* Ignore wal frames before this one */
  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
#ifdef SQLITE_ENABLE_SNAPSHOT
  WalIndexHdr *pSnapshot;    /* Start transaction here if not NULL */
#endif
};

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

    /* Reset the checkpoint-header. This is safe because this thread is 
    ** currently holding locks that exclude all other readers, writers and
    ** checkpointers.
    */
    pInfo = walCkptInfo(pWal);
    pInfo->nBackfill = 0;
    pInfo->nBackfillAttempted = pWal->hdr.mxFrame;
    pInfo->aReadMark[0] = 0;
    for(i=1; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
    if( pWal->hdr.mxFrame ) pInfo->aReadMark[1] = pWal->hdr.mxFrame;

    /* If more than one frame was recovered from the log file, report an
    ** event via sqlite3_log(). This is to help with identifying performance
    ** problems caused by applications routinely shutting down without

  assert( zWalName && zWalName[0] );
  assert( pDbFd );

  /* In the amalgamation, the os_unix.c and os_win.c source files come before
  ** this source file.  Verify that the #defines of the locking byte offsets
  ** in os_unix.c and os_win.c agree with the WALINDEX_LOCK_OFFSET value.
  ** For that matter, if the lock offset ever changes from its initial design
  ** value of 120, we need to know that so there is an assert() to check it.
  */
  assert( 120==WALINDEX_LOCK_OFFSET );
  assert( 136==WALINDEX_HDR_SIZE );
#ifdef WIN_SHM_BASE
  assert( WIN_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif
#ifdef UNIX_SHM_BASE
  assert( UNIX_SHM_BASE==WALINDEX_LOCK_OFFSET );
#endif

  u32 *aSalt = pWal->hdr.aSalt;   /* Big-endian salt values */
  pWal->nCkpt++;
  pWal->hdr.mxFrame = 0;
  sqlite3Put4byte((u8*)&aSalt[0], 1 + sqlite3Get4byte((u8*)&aSalt[0]));
  memcpy(&pWal->hdr.aSalt[1], &salt1, 4);
  walIndexWriteHdr(pWal);
  pInfo->nBackfill = 0;
  pInfo->nBackfillAttempted = 0;
  pInfo->aReadMark[1] = 0;
  for(i=2; i<WAL_NREADER; i++) pInfo->aReadMark[i] = READMARK_NOT_USED;
  assert( pInfo->aReadMark[0]==0 );
}

/*
** Copy as much content as we can from the WAL back into the database file

    }

    if( pInfo->nBackfill<mxSafeFrame
     && (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0),1))==SQLITE_OK
    ){
      i64 nSize;                    /* Current size of database file */
      u32 nBackfill = pInfo->nBackfill;

      pInfo->nBackfillAttempted = mxSafeFrame;

      /* Sync the WAL to disk */
      if( sync_flags ){
        rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
      }

      /* If the database may grow as a result of this checkpoint, hint

*/
static int walTryBeginRead(Wal *pWal, int *pChanged, int useWal, int cnt){
  volatile WalCkptInfo *pInfo;    /* Checkpoint information in wal-index */
  u32 mxReadMark;                 /* Largest aReadMark[] value */
  int mxI;                        /* Index of largest aReadMark[] value */
  int i;                          /* Loop counter */
  int rc = SQLITE_OK;             /* Return code  */
  u32 mxFrame;                    /* Wal frame to lock to */

  assert( pWal->readLock<0 );     /* Not currently locked */

  /* Take steps to avoid spinning forever if there is a protocol error.
  **
  ** Circumstances that cause a RETRY should only last for the briefest
  ** instances of time.  No I/O or other system calls are done while the

    }
    if( rc!=SQLITE_OK ){
      return rc;
    }
  }

  pInfo = walCkptInfo(pWal);
  if( !useWal && pInfo->nBackfill==pWal->hdr.mxFrame 
#ifdef SQLITE_ENABLE_SNAPSHOT
   && (pWal->pSnapshot==0 || pWal->hdr.mxFrame==0
     || 0==memcmp(&pWal->hdr, pWal->pSnapshot, sizeof(WalIndexHdr)))
#endif
  ){
    /* The WAL has been completely backfilled (or it is empty).
    ** and can be safely ignored.
    */
    rc = walLockShared(pWal, WAL_READ_LOCK(0));
    walShmBarrier(pWal);
    if( rc==SQLITE_OK ){
      if( memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr)) ){

  /* If we get this far, it means that the reader will want to use
  ** the WAL to get at content from recent commits.  The job now is
  ** to select one of the aReadMark[] entries that is closest to
  ** but not exceeding pWal->hdr.mxFrame and lock that entry.
  */
  mxReadMark = 0;
  mxI = 0;
  mxFrame = pWal->hdr.mxFrame;
#ifdef SQLITE_ENABLE_SNAPSHOT
  if( pWal->pSnapshot && pWal->pSnapshot->mxFrame<mxFrame ){
    mxFrame = pWal->pSnapshot->mxFrame;
  }
#endif
  for(i=1; i<WAL_NREADER; i++){
    u32 thisMark = pInfo->aReadMark[i];
    if( mxReadMark<=thisMark && thisMark<=mxFrame ){
      assert( thisMark!=READMARK_NOT_USED );
      mxReadMark = thisMark;
      mxI = i;
    }
  }


  if( (pWal->readOnly & WAL_SHM_RDONLY)==0
   && (mxReadMark<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] = 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 || (pWal->readOnly & WAL_SHM_RDONLY)!=0 );
    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
  ** value in the aReadMark[] array or the contents of the wal-index
  ** header have changed.
  **
  ** It is necessary to check that the wal-index header did not change
  ** between the time it was read and when the shared-lock was obtained
  ** on WAL_READ_LOCK(mxI) was obtained to account for the possibility
  ** that the log file may have been wrapped by a writer, or that frames
  ** that occur later in the log than pWal->hdr.mxFrame may have been
  ** copied into the database by a checkpointer. If either of these things
  ** happened, then reading the database with the current value of
  ** pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
  ** instead.
  **
  ** Before checking that the live wal-index header has not changed
  ** since it was read, set Wal.minFrame to the first frame in the wal
  ** file that has not yet been checkpointed. This client will not need
  ** to read any frames earlier than minFrame from the wal file - they
  ** can be safely read directly from the database file.
  **
  ** Because a ShmBarrier() call is made between taking the copy of 
  ** nBackfill and checking that the wal-header in shared-memory still
  ** matches the one cached in pWal->hdr, it is guaranteed that the 
  ** checkpointer that set nBackfill was not working with a wal-index
  ** header newer than that cached in pWal->hdr. If it were, that could
  ** cause a problem. The checkpointer could omit to checkpoint
  ** a version of page X that lies before pWal->minFrame (call that version
  ** A) on the basis that there is a newer version (version B) of the same
  ** page later in the wal file. But if version B happens to like past
  ** frame pWal->hdr.mxFrame - then the client would incorrectly assume
  ** that it can read version A from the database file. However, since
  ** we can guarantee that the checkpointer that set nBackfill could not
  ** see any pages past pWal->hdr.mxFrame, this problem does not come up.
  */
  pWal->minFrame = pInfo->nBackfill+1;
  walShmBarrier(pWal);
  if( pInfo->aReadMark[mxI]!=mxReadMark
   || memcmp((void *)walIndexHdr(pWal), &pWal->hdr, sizeof(WalIndexHdr))
  ){
    walUnlockShared(pWal, WAL_READ_LOCK(mxI));
    return WAL_RETRY;
  }else{
    assert( mxReadMark<=pWal->hdr.mxFrame );
    pWal->readLock = (i16)mxI;

  }
  return rc;
}

/*
** Begin a read transaction on the database.
**

** Pager layer will use this to know that is cache is stale and
** needs to be flushed.
*/
int sqlite3WalBeginReadTransaction(Wal *pWal, int *pChanged){
  int rc;                         /* Return code */
  int cnt = 0;                    /* Number of TryBeginRead attempts */

#ifdef SQLITE_ENABLE_SNAPSHOT
  int bChanged = 0;
  WalIndexHdr *pSnapshot = pWal->pSnapshot;
  if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
    bChanged = 1;
  }
#endif

  do{
    rc = walTryBeginRead(pWal, pChanged, 0, ++cnt);
  }while( rc==WAL_RETRY );
  testcase( (rc&0xff)==SQLITE_BUSY );
  testcase( (rc&0xff)==SQLITE_IOERR );
  testcase( rc==SQLITE_PROTOCOL );
  testcase( rc==SQLITE_OK );

#ifdef SQLITE_ENABLE_SNAPSHOT
  if( rc==SQLITE_OK ){
    if( pSnapshot && memcmp(pSnapshot, &pWal->hdr, sizeof(WalIndexHdr))!=0 ){
      /* At this point the client has a lock on an aReadMark[] slot holding
      ** a value equal to or smaller than pSnapshot->mxFrame, but pWal->hdr
      ** is populated with the wal-index header corresponding to the head
      ** of the wal file. Verify that pSnapshot is still valid before
      ** continuing.  Reasons why pSnapshot might no longer be valid:
      **
      **    (1)  The WAL file has been reset since the snapshot was taken.
      **         In this case, the salt will have changed.
      **
      **    (2)  A checkpoint as been attempted that wrote frames past
      **         pSnapshot->mxFrame into the database file.  Note that the
      **         checkpoint need not have completed for this to cause problems.
      */
      volatile WalCkptInfo *pInfo = walCkptInfo(pWal);

      assert( pWal->readLock>0 || pWal->hdr.mxFrame==0 );
      assert( pInfo->aReadMark[pWal->readLock]<=pSnapshot->mxFrame );

      /* It is possible that there is a checkpointer thread running 
      ** concurrent with this code. If this is the case, it may be that the
      ** checkpointer has already determined that it will checkpoint 
      ** snapshot X, where X is later in the wal file than pSnapshot, but 
      ** has not yet set the pInfo->nBackfillAttempted variable to indicate 
      ** its intent. To avoid the race condition this leads to, ensure that
      ** there is no checkpointer process by taking a shared CKPT lock 
      ** before checking pInfo->nBackfillAttempted.  */
      rc = walLockShared(pWal, WAL_CKPT_LOCK);

      if( rc==SQLITE_OK ){
        /* Check that the wal file has not been wrapped. Assuming that it has
        ** not, also check that no checkpointer has attempted to checkpoint any
        ** frames beyond pSnapshot->mxFrame. If either of these conditions are
        ** true, return SQLITE_BUSY_SNAPSHOT. Otherwise, overwrite pWal->hdr
        ** with *pSnapshot and set *pChanged as appropriate for opening the
        ** snapshot.  */
        if( !memcmp(pSnapshot->aSalt, pWal->hdr.aSalt, sizeof(pWal->hdr.aSalt))
         && pSnapshot->mxFrame>=pInfo->nBackfillAttempted
        ){
          memcpy(&pWal->hdr, pSnapshot, sizeof(WalIndexHdr));
          *pChanged = bChanged;
        }else{
          rc = SQLITE_BUSY_SNAPSHOT;
        }

        /* Release the shared CKPT lock obtained above. */
        walUnlockShared(pWal, WAL_CKPT_LOCK);
      }


      if( rc!=SQLITE_OK ){
        sqlite3WalEndReadTransaction(pWal);
      }
    }
  }
#endif
  return rc;
}

/*
** Finish with a read transaction.  All this does is release the
** read-lock.
*/

** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
** WAL module is using shared-memory, return false. 
*/
int sqlite3WalHeapMemory(Wal *pWal){
  return (pWal && pWal->exclusiveMode==WAL_HEAPMEMORY_MODE );
}

#ifdef SQLITE_ENABLE_SNAPSHOT
/* Create a snapshot object.  The content of a snapshot is opaque to
** every other subsystem, so the WAL module can put whatever it needs
** in the object.
*/
int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot){
  int rc = SQLITE_OK;
  WalIndexHdr *pRet;

  assert( pWal->readLock>=0 && pWal->writeLock==0 );

  pRet = (WalIndexHdr*)sqlite3_malloc(sizeof(WalIndexHdr));
  if( pRet==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memcpy(pRet, &pWal->hdr, sizeof(WalIndexHdr));
    *ppSnapshot = (sqlite3_snapshot*)pRet;
  }

  return rc;
}

/* Try to open on pSnapshot when the next read-transaction starts
*/
void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot){
  pWal->pSnapshot = (WalIndexHdr*)pSnapshot;
}
#endif /* SQLITE_ENABLE_SNAPSHOT */

#ifdef SQLITE_ENABLE_ZIPVFS
/*
** If the argument is not NULL, it points to a Wal object that holds a
** read-lock. This function returns the database page-size if it is known,
** or zero if it is not (or if pWal is NULL).
*/
int sqlite3WalFramesize(Wal *pWal){
  assert( pWal==0 || pWal->readLock>=0 );
  return (pWal ? pWal->szPage : 0);
}
#endif

#endif /* #ifndef SQLITE_OMIT_WAL */

int sqlite3WalExclusiveMode(Wal *pWal, int op);

/* Return true if the argument is non-NULL and the WAL module is using
** heap-memory for the wal-index. Otherwise, if the argument is NULL or the
** WAL module is using shared-memory, return false. 
*/
int sqlite3WalHeapMemory(Wal *pWal);

#ifdef SQLITE_ENABLE_SNAPSHOT
int sqlite3WalSnapshotGet(Wal *pWal, sqlite3_snapshot **ppSnapshot);
void sqlite3WalSnapshotOpen(Wal *pWal, sqlite3_snapshot *pSnapshot);
#endif

#ifdef SQLITE_ENABLE_ZIPVFS
/* If the WAL file is not empty, return the number of bytes of content
** stored in each frame (i.e. the db page-size when the WAL was created).
*/
int sqlite3WalFramesize(Wal *pWal);
#endif

      PRAGMA aux.freelist_count;
    }
  } {9 9}
}

# Default setting of PRAGMA cache_spill is always ON
#
# EVIDENCE-OF: R-63549-59887 PRAGMA cache_spill; PRAGMA
# cache_spill=boolean; PRAGMA schema.cache_spill=N;
#
# EVIDENCE-OF: R-23955-02765 Cache_spill is enabled by default
#
db close
delete_file test.db test.db-journal
delete_file test2.db test2.db-journal
sqlite3 db test.db

    PRAGMA cache_spill=OFF;
    PRAGMA Cache_Spill;
    BEGIN;
    UPDATE t1 SET c=c+1;
    PRAGMA lock_status;
  }
} {0 main reserved temp unknown}   ;# No cache spill, so no exclusive lock


# EVIDENCE-OF: R-34657-61226 The "PRAGMA cache_spill=N" form of this
# pragma sets a minimum cache size threshold required for spilling to
# occur.
do_test pragma2-4.5.2 {
  db eval {
    ROLLBACK;
    PRAGMA cache_spill=100000;
    PRAGMA cache_spill;
    BEGIN;
    UPDATE t1 SET c=c+1;

# 2015 December 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 regression tests for SQLite library. The focus
# of this file is the sqlite3_snapshot_xxx() APIs.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
ifcapable !snapshot {finish_test; return}
set testprefix snapshot

#-------------------------------------------------------------------------
# Check some error conditions in snapshot_get(). It is an error if:
#
#  1) snapshot_get() is called on a non-WAL database, or
#  2) there is an open write transaction on the database.
#
do_execsql_test 1.0 {
  CREATE TABLE t1(a, b);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
}

do_test 1.1.1 {
  execsql { BEGIN; SELECT * FROM t1; }
  list [catch { sqlite3_snapshot_get db main } msg] $msg
} {1 SQLITE_ERROR}
do_execsql_test 1.1.2 COMMIT

do_test 1.2.1 {
  execsql {
    PRAGMA journal_mode = WAL;
    BEGIN;
      INSERT INTO t1 VALUES(5, 6);
      INSERT INTO t1 VALUES(7, 8);
  }
  list [catch { sqlite3_snapshot_get db main } msg] $msg
} {1 SQLITE_ERROR}
do_execsql_test 1.3.2 COMMIT

#-------------------------------------------------------------------------
# Check that a simple case works. Reuse the database created by the
# block of tests above.
#
do_execsql_test 2.1.0 {
  BEGIN;
    SELECT * FROM t1;
} {1 2 3 4 5 6 7 8}

breakpoint
do_test 2.1.1 {
  set snapshot [sqlite3_snapshot_get db main]
  execsql {
    COMMIT;
    INSERT INTO t1 VALUES(9, 10);
    SELECT * FROM t1;
  }
} {1 2 3 4 5 6 7 8 9 10}

do_test 2.1.2 {
  execsql BEGIN
  sqlite3_snapshot_open db main $snapshot
  execsql {
    SELECT * FROM t1;
  }
} {1 2 3 4 5 6 7 8}

do_test 2.1.3 {
  sqlite3_snapshot_free $snapshot
  execsql COMMIT
} {}

do_test 2.2.0 {
  sqlite3 db2 test.db
  execsql {
    BEGIN;
      SELECT * FROM t1;
  } db2
} {1 2 3 4 5 6 7 8 9 10}

do_test 2.2.1 {
  set snapshot [sqlite3_snapshot_get db2 main]
  execsql {
    INSERT INTO t1 VALUES(11, 12);
    SELECT * FROM t1;
  }
} {1 2 3 4 5 6 7 8 9 10 11 12}

do_test 2.2.2 {
  execsql BEGIN
  sqlite3_snapshot_open db main $snapshot
  execsql {
    SELECT * FROM t1;
  }
} {1 2 3 4 5 6 7 8 9 10}

do_test 2.2.3 {
  sqlite3_snapshot_free $snapshot
  execsql COMMIT
  execsql COMMIT db2
  db2 close
} {}

do_test 2.3.1 {
  execsql { DELETE FROM t1 WHERE a>6 }
  set snapshot [sqlite3_snapshot_get db main]
  execsql {
    INSERT INTO t1 VALUES('a', 'b');
    INSERT INTO t1 VALUES('c', 'd');
    SELECT * FROM t1;
  }
} {1 2 3 4 5 6 a b c d}
do_test 2.3.2 {
  execsql BEGIN
  sqlite3_snapshot_open db main $snapshot
  execsql { SELECT * FROM t1 }
} {1 2 3 4 5 6}

do_test 2.3.3 {
  catchsql {
    INSERT INTO t1 VALUES('x','y')
  }
} {1 {database is locked}}
do_test 2.3.4 {
  execsql COMMIT
  sqlite3_snapshot_free $snapshot
} {}

#-------------------------------------------------------------------------
# Check some errors in sqlite3_snapshot_open(). It is an error if:
#
#   1) the db is in auto-commit mode,
#   2) the db has an open (read or write) transaction,
#   3) the db is not a wal database,
#
# Reuse the database created by earlier tests.
#
do_execsql_test 3.0.0 {
  CREATE TABLE t2(x, y);
  INSERT INTO t2 VALUES('a', 'b');
  INSERT INTO t2 VALUES('c', 'd');
  BEGIN;
    SELECT * FROM t2;
} {a b c d}
do_test 3.0.1 {
  set snapshot [sqlite3_snapshot_get db main]
  execsql { COMMIT }
  execsql { INSERT INTO t2 VALUES('e', 'f'); }
} {}

do_test 3.1 {
  list [catch {sqlite3_snapshot_open db main $snapshot } msg] $msg
} {1 SQLITE_ERROR}

do_test 3.2.1 {
  execsql {
    BEGIN;
      SELECT * FROM t2;
  }
} {a b c d e f}
do_test 3.2.2 {
  list [catch {sqlite3_snapshot_open db main $snapshot } msg] $msg
} {1 SQLITE_ERROR}

do_test 3.2.3 {
  execsql {
    COMMIT;
    BEGIN;
      INSERT INTO t2 VALUES('g', 'h');
  }
  list [catch {sqlite3_snapshot_open db main $snapshot } msg] $msg
} {1 SQLITE_ERROR}
do_execsql_test 3.2.4 COMMIT

do_test 3.3.1 {
  execsql { PRAGMA journal_mode = DELETE }
  execsql { BEGIN }
  list [catch {sqlite3_snapshot_open db main $snapshot } msg] $msg
} {1 SQLITE_ERROR}

do_test 3.3.2 {
  sqlite3_snapshot_free $snapshot
  execsql COMMIT
} {}

#-------------------------------------------------------------------------
# Check that SQLITE_BUSY_SNAPSHOT is returned if the specified snapshot
# no longer exists because the wal file has been checkpointed.
#
#   1. Reading a snapshot from the middle of a wal file is not possible
#      after the wal file has been checkpointed.
#
#   2. That a snapshot from the end of a wal file can not be read once
#      the wal file has been wrapped.
#
do_execsql_test 4.1.0 {
  PRAGMA journal_mode = wal;
  CREATE TABLE t3(i, j);
  INSERT INTO t3 VALUES('o', 't');
  INSERT INTO t3 VALUES('t', 'f');
  BEGIN;
    SELECT * FROM t3;
} {wal o t t f}

do_test 4.1.1 {
  set snapshot [sqlite3_snapshot_get db main]
  execsql COMMIT
} {}
do_test 4.1.2 {
  execsql { 
    INSERT INTO t3 VALUES('f', 's'); 
    BEGIN;
  }
  sqlite3_snapshot_open db main $snapshot
  execsql { SELECT * FROM t3 }
} {o t t f}

do_test 4.1.3 {
  execsql { 
    COMMIT;
    PRAGMA wal_checkpoint;
    BEGIN;
  }
  list [catch {sqlite3_snapshot_open db main $snapshot} msg] $msg
} {1 SQLITE_BUSY_SNAPSHOT}
do_test 4.1.4 {
  sqlite3_snapshot_free $snapshot
  execsql COMMIT
} {}

do_test 4.2.1 {
  execsql {
    INSERT INTO t3 VALUES('s', 'e');
    INSERT INTO t3 VALUES('n', 't');
    BEGIN;
      SELECT * FROM t3;
  }
} {o t t f f s s e n t}
do_test 4.2.2 {
  set snapshot [sqlite3_snapshot_get db main]
  execsql {
    COMMIT;
    PRAGMA wal_checkpoint;
    BEGIN;
  }
  sqlite3_snapshot_open db main $snapshot
  execsql { SELECT * FROM t3 }
} {o t t f f s s e n t}
do_test 4.2.3 {
  execsql {
    COMMIT;
    INSERT INTO t3 VALUES('e', 't');
    BEGIN;
  }
  list [catch {sqlite3_snapshot_open db main $snapshot} msg] $msg
} {1 SQLITE_BUSY_SNAPSHOT}
do_test 4.2.4 {
  sqlite3_snapshot_free $snapshot
} {}

#-------------------------------------------------------------------------
# Check that SQLITE_BUSY is returned if a checkpoint is running when
# sqlite3_snapshot_open() is called.
#
reset_db
db close
testvfs tvfs
sqlite3 db test.db -vfs tvfs

do_execsql_test 5.1 {
  PRAGMA journal_mode = wal;
  CREATE TABLE x1(x, xx, xxx);
  INSERT INTO x1 VALUES('z', 'zz', 'zzz');
  BEGIN;
    SELECT * FROM x1;
} {wal z zz zzz}

do_test 5.2 {
  set ::snapshot [sqlite3_snapshot_get db main]
  sqlite3 db2 test.db -vfs tvfs
  execsql {
    INSERT INTO x1 VALUES('a', 'aa', 'aaa');
    COMMIT;
  }
} {}

set t53 0
proc write_callback {args} {
  do_test 5.3.[incr ::t53] {
    execsql BEGIN
    list [catch { sqlite3_snapshot_open db main $::snapshot } msg] $msg
  } {1 SQLITE_BUSY}
  catchsql COMMIT
}

tvfs filter xWrite
tvfs script write_callback
db2 eval { PRAGMA wal_checkpoint }
db close
db2 close
tvfs delete
sqlite3_snapshot_free $snapshot

#-------------------------------------------------------------------------
# Test that sqlite3_snapshot_get() may be called immediately after
# "BEGIN; PRAGMA user_version;". And that sqlite3_snapshot_open() may
# be called after opening the db handle and running the script
# "PRAGMA user_version; BEGIN".
reset_db
do_execsql_test 6.1 {
  PRAGMA journal_mode = wal;
  CREATE TABLE x1(x, xx, xxx);
  INSERT INTO x1 VALUES('z', 'zz', 'zzz');
  BEGIN;
    PRAGMA user_version;
} {wal 0}
do_test 6.2 {
  set ::snapshot [sqlite3_snapshot_get db main]
  execsql {
    INSERT INTO x1 VALUES('a', 'aa', 'aaa');
    COMMIT;
  }
} {}
do_test 6.3 {
  sqlite3 db2 test.db 
  db2 eval "PRAGMA user_version ; BEGIN"
  sqlite3_snapshot_open db2 main $::snapshot
  db2 eval { SELECT * FROM x1 }
} {z zz zzz}
sqlite3_snapshot_free $snapshot

finish_test

# 2015 December 10
#
# 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 regression tests for SQLite library. The focus
# of this file is the sqlite3_snapshot_xxx() APIs.
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
ifcapable !snapshot {finish_test; return}
set testprefix snapshot_fault

#-------------------------------------------------------------------------
# Check that an sqlite3_snapshot_open() client cannot be tricked into
# reading a corrupt snapshot even if a second client fails while 
# checkpointing the db.
#
do_faultsim_test 1.0 -prep {
  faultsim_delete_and_reopen
  sqlite3 db2 test.db
  db2 eval { 
    CREATE TABLE t1(a, b UNIQUE, c UNIQUE);
    INSERT INTO t1 VALUES(1, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(2, randomblob(500), randomblob(500));
    PRAGMA journal_mode = wal;
    INSERT INTO t1 VALUES(3, randomblob(500), randomblob(500));
    BEGIN;
      SELECT a FROM t1;
  }
  set ::snapshot [sqlite3_snapshot_get db2 main] 
  db2 eval COMMIT
  db2 eval {
    UPDATE t1 SET b=randomblob(501), c=randomblob(501) WHERE a=1;
    INSERT INTO t1 VALUES(4, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(5, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(6, randomblob(500), randomblob(500));
  }
} -body {
  db eval { PRAGMA wal_checkpoint }
} -test {
  db2 eval BEGIN
  if {[catch { sqlite3_snapshot_open db2 main $::snapshot } msg]} {
    if {$msg != "SQLITE_BUSY_SNAPSHOT" && $msg != "SQLITE_BUSY"} {
      error "error is $msg" 
    }
  } else {
    set res [db2 eval { 
      SELECT a FROM t1;
      PRAGMA integrity_check;
    }]
    if {$res != "1 2 3 ok"} { error "res is $res" }
  }

  sqlite3_snapshot_free $::snapshot
}

#-------------------------------------------------------------------------
# This test is similar to the previous one. Except, after the 
# "PRAGMA wal_checkpoint" command fails the db is closed and reopened
# so as to require wal file recovery. It should not be possible to open
# a snapshot that is part of the body of a recovered wal file.
#
do_faultsim_test 2.0 -prep {
  faultsim_delete_and_reopen
  db eval { 
    CREATE TABLE t1(a, b UNIQUE, c UNIQUE);
    INSERT INTO t1 VALUES(1, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(2, randomblob(500), randomblob(500));
    PRAGMA journal_mode = wal;
    INSERT INTO t1 VALUES(3, randomblob(500), randomblob(500));
    BEGIN;
      SELECT a FROM t1;
  }
  set ::snapshot [sqlite3_snapshot_get db main] 
  db eval COMMIT

  db eval {
    UPDATE t1 SET b=randomblob(501), c=randomblob(501) WHERE a=1;
    INSERT INTO t1 VALUES(4, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(5, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(6, randomblob(500), randomblob(500));
  }
} -body {
  db eval { PRAGMA wal_checkpoint }
} -test {

  db_save
  db close
  db_restore_and_reopen
  db eval { SELECT * FROM t1 }
  
  db eval BEGIN
  if {[catch { sqlite3_snapshot_open db main $::snapshot } msg]} {
    if {$msg != "SQLITE_BUSY_SNAPSHOT" && $msg != "SQLITE_BUSY"} {
      error "error is $msg" 
    }
  } else {
    # This branch should actually never be taken. But it was useful in
    # determining whether or not this test was actually working (by 
    # running a modified version of SQLite that allowed snapshots to be
    # opened following a recovery).
    error "TEST HAS FAILED"

    set res [db eval { 
      SELECT a FROM t1;
      PRAGMA integrity_check;
    }]
    if {$res != "1 2 3 ok"} { error "res is $res" }
  }

  sqlite3_snapshot_free $::snapshot
}

#-------------------------------------------------------------------------
# Test the handling of faults that occur within sqlite3_snapshot_open().
#
do_faultsim_test 3.0 -prep {
  faultsim_delete_and_reopen
  db eval { 
    CREATE TABLE t1(a, b UNIQUE, c UNIQUE);
    INSERT INTO t1 VALUES(1, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(2, randomblob(500), randomblob(500));
    PRAGMA journal_mode = wal;
    INSERT INTO t1 VALUES(3, randomblob(500), randomblob(500));
    BEGIN;
      SELECT a FROM t1;
  }
  set ::snapshot [sqlite3_snapshot_get db main] 
  db eval COMMIT
  db eval {
    UPDATE t1 SET b=randomblob(501), c=randomblob(501) WHERE a=1;
    INSERT INTO t1 VALUES(4, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(5, randomblob(500), randomblob(500));
    INSERT INTO t1 VALUES(6, randomblob(500), randomblob(500));
    BEGIN;
  }
} -body {
  if { [catch { sqlite3_snapshot_open db main $::snapshot } msg] } {
    error $msg
  }
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_IOERR} \
                              {1 SQLITE_IOERR_NOMEM} {1 SQLITE_IOERR_READ}
  if {$testrc==0} {
    set res [db eval { 
      SELECT a FROM t1;
      PRAGMA integrity_check;
    }]
    if {$res != "1 2 3 ok"} { error "res is $res" }
  }

  sqlite3_snapshot_free $::snapshot
}



finish_test

  test_syscall reset
  test_syscall install {fstat fallocate}
}
do_faultsim_test 3 -faults vfsfault-* -prep {
  faultsim_delete_and_reopen
  file_control_chunksize_test db main 8192
  execsql {
    PRAGMA synchronous=OFF;
    CREATE TABLE t1(a, b);
    BEGIN;
      SELECT * FROM t1;
  }
} -body {
  test_syscall errno fstat     EIO
  test_syscall errno fallocate EIO

#include <assert.h>
#include <sys/types.h> 
#include <sys/stat.h> 
#include <string.h>
#include <fcntl.h>
#include <errno.h>

#include "test_multiplex.h"

/* Required to link test_multiplex.c */
#ifndef SQLITE_OMIT_WSD
int sqlite3PendingByte = 0x40000000;
#endif

/*
 * This code implements the MD5 message-digest algorithm.
 * The algorithm is due to Ron Rivest.  This code was
 * written by Colin Plumb in 1993, no copyright is claimed.
 * This code is in the public domain; do with it what you wish.
 *
 * Equivalent code is available from RSA Data Security, Inc.

  int nTestfound = 0;

  sqlite3_config(SQLITE_CONFIG_MULTITHREAD);
  if( argc<2 ){
    argc = 2;
    argv = substArgv;
  }

  /* Loop through the command-line arguments to ensure that each argument
  ** selects at least one test. If not, assume there is a typo on the 
  ** command-line and bail out with the usage message.  */
  for(iArg=1; iArg<argc; iArg++){
    const char *zArg = argv[iArg];
    if( zArg[0]=='-' ){
      if( sqlite3_stricmp(zArg, "-multiplexor")==0 ){
        /* Install the multiplexor VFS as the default */
        int rc = sqlite3_multiplex_initialize(0, 1);
        if( rc!=SQLITE_OK ){
          fprintf(stderr, "Failed to install multiplexor VFS (%d)\n", rc);
          return 253;
        }
      }
      else {
        goto usage;
      }

      continue;
    }

    for(i=0; i<sizeof(aTest)/sizeof(aTest[0]); i++){
      if( sqlite3_strglob(zArg, aTest[i].zTest)==0 ) break;
    }
    if( i>=sizeof(aTest)/sizeof(aTest[0]) ) goto usage;   
  }

  for(iArg=1; iArg<argc; iArg++){
    if( argv[iArg][0]=='-' ) continue;
    for(i=0; i<sizeof(aTest)/sizeof(aTest[0]); i++){
      char const *z = aTest[i].zTest;
      if( sqlite3_strglob(argv[iArg],z)==0 ){
        printf("Running %s for %d seconds...\n", z, aTest[i].nMs/1000);
        fflush(stdout);
        aTest[i].xTest(aTest[i].nMs);
        nTestfound++;
      }
    }
  }
  if( nTestfound==0 ) goto usage;

  printf("%d errors out of %d tests\n", nGlobalErr, nTestfound);
  return (nGlobalErr>0 ? 255 : 0);

 usage:
  printf("Usage: %s [-multiplexor] [testname|testprefix*]...\n", argv[0]);
  printf("Available tests are:\n");
  for(i=0; i<sizeof(aTest)/sizeof(aTest[0]); i++){
    printf("   %s\n", aTest[i].zTest);
  }

  return 254;
}

      set res [list]
      foreach name [glob -directory $::env(SystemDrive)/ -- *] {
        if {[string index [file tail $name] 0] eq "."} continue
        lappend res $name
      }
      return $res
    } else {
      return [string map {/ {}} [glob /*]]
    }
  }

  proc list_files { pattern } {
    if {$::tcl_platform(platform) eq "windows"} {
      set res [list]
      foreach name [glob -nocomplain $pattern] {

    SELECT size FROM fstree WHERE path = $pwd || '/subdir/x1.txt'
  } 143

}


finish_test

    INSERT INTO t1 VALUES(4,5,10,15);
    INSERT INTO t1 VALUES(5,10,100,1000);
    CREATE INDEX t1b ON t1(b);
    CREATE INDEX t1c ON t1(c);
    SELECT * FROM t1;
  }
} {1 2 3 4 2 3 4 5 3 4 6 8 4 5 10 15 5 10 100 1000}
do_execsql_test where7-1.1.1 {
  CREATE TABLE t(a);
  CREATE INDEX ta ON t(a);
  INSERT INTO t(a) VALUES(1),(2);
  SELECT * FROM t ORDER BY a;
  SELECT * FROM t WHERE a<2 OR a<3 ORDER BY a;
  PRAGMA count_changes=ON;
  DELETE FROM t WHERE a<2 OR a<3;
  SELECT * FROM t;
  PRAGMA count_changes=OFF;
  DROP TABLE t;
} {1 2 1 2 2}
do_test where7-1.2 {
  count_steps {
    SELECT a FROM t1 WHERE b=3 OR c=6 ORDER BY a
  }
} {2 3 scan 0 sort 1}
do_test where7-1.3 {
  count_steps {

  ECHO The TEMP environment variable must be set first.
  GOTO errors
)

%_VECHO% Temp = '%TEMP%'

IF NOT DEFINED TCLKIT_URI (
  SET TCLKIT_URI=https://tclsh.com/
)

%_VECHO% TclKitUri = '%TCLKIT_URI%'

IF /I "%PROCESSOR%" == "x86" (
  CALL :fn_TclKitX86Variables
) ELSE IF /I "%PROCESSOR%" == "x64" (

REM
REM NOTE: This is the name of the sub-directory where the UCRT libraries may
REM       be found.  It is only used when compiling against the UCRT.
REM
IF DEFINED UCRTVersion (
  SET NUCRTVER=%UCRTVersion%
) ELSE (
  SET NUCRTVER=10.0.10586.0
)

REM
REM NOTE: This is the name of the sub-directory where the Windows 10.0 SDK
REM       libraries may be found.  It is only used when compiling with the
REM       Windows 10.0 SDK.
REM