SQLite

typedef struct SessionChange SessionChange;
typedef struct SessionBuffer SessionBuffer;
typedef struct SessionInput SessionInput;

/*
** Minimum chunk size used by streaming versions of functions.
*/
#ifdef SQLITE_TEST
#define SESSIONS_STR_CHUNK_SIZE 1
#else
#define SESSIONS_STR_CHUNK_SIZE 1024
#endif

/*
** Session handle structure.
*/
struct sqlite3_session {
  sqlite3 *db;                    /* Database handle session is attached to */
  char *zDb;                      /* Name of database session is attached to */

/*
** An object of this type is used internally as an abstraction for the 
** input data read by changeset iterators. Input data may be supplied 
** either as a single large buffer (sqlite3changeset_start()) or using
** a stream function (sqlite3changeset_start_str()).
*/
struct SessionInput {
  int iNext;                      /* Offset in aData[] of next change */
  u8 *aData;                      /* Pointer to buffer containing changeset */
  int nData;                      /* Number of bytes in aData */

  SessionBuffer buf;              /* Current read buffer */
  int (*xInput)(void*, void*, int*);        /* Input stream call (or NULL) */
  void *pIn;                                /* First argument to xInput */
  int bEof;                       /* Set to true after xInput finished */
};

/*

  *pp = 0;

  /* Allocate and initialize the iterator structure. */
  nByte = sizeof(sqlite3_changeset_iter);
  pRet = (sqlite3_changeset_iter *)sqlite3_malloc(nByte);
  if( !pRet ) return SQLITE_NOMEM;
  memset(pRet, 0, sizeof(sqlite3_changeset_iter));
  pRet->in.aData = (u8 *)pChangeset;
  pRet->in.nData = nChangeset;
  pRet->in.xInput = xInput;
  pRet->in.pIn = pIn;
  pRet->in.iNext = 0;
  pRet->in.bEof = (xInput ? 0 : 1);

  /* Populate the output variable and return success. */
  *pp = pRet;

/*
** Ensure that there are at least nByte bytes available in the buffer. Or,
** if there are not nByte bytes remaining in the input, that all available
** data is in the buffer.
**
** Return an SQLite error code if an error occurs, or SQLITE_OK otherwise.
*/
static int sessionInputBuffer(SessionInput *pIn, int nByte){
  int rc = SQLITE_OK;
  if( pIn->xInput ){
    while( !pIn->bEof && (pIn->iNext+nByte)>=pIn->nData && rc==SQLITE_OK ){
      int nNew = SESSIONS_STR_CHUNK_SIZE;

      if( pIn->iNext>=SESSIONS_STR_CHUNK_SIZE ){
        int nMove = pIn->buf.nBuf - pIn->iNext;
        memmove(pIn->buf.aBuf, &pIn->buf.aBuf[pIn->iNext], nMove);
        pIn->buf.nBuf -= pIn->iNext;
        pIn->iNext = 0;
      }

      if( SQLITE_OK==sessionBufferGrow(&pIn->buf, nNew, &rc) ){
        rc = pIn->xInput(pIn->pIn, &pIn->buf.aBuf[pIn->buf.nBuf], &nNew);
        if( nNew==0 ){
          pIn->bEof = 1;
        }else{
          pIn->buf.nBuf += nNew;
        }
      }

      pIn->aData = pIn->buf.aBuf;
      pIn->nData = pIn->buf.nBuf;
    }
  }
  return rc;
}

/*
** When this function is called, *ppRec points to the start of a record
** that contains nCol values. This function advances the pointer *ppRec

    }else if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
      aRec += 8;
    }
  }

  *ppRec = aRec;
}

/*
** This function sets the value of the sqlite3_value object passed as the
** first argument to a copy of the string or blob held in the aData[] 
** buffer. SQLITE_OK is returned if successful, or SQLITE_NOMEM if an OOM
** error occurs.
*/
static int sessionValueSetStr(
  sqlite3_value *pVal,            /* Set the value of this object */
  u8 *aData,                      /* Buffer containing string or blob data */
  int nData,                      /* Size of buffer aData[] in bytes */
  u8 enc                          /* String encoding (0 for blobs) */
){
  u8 *aCopy = sqlite3_malloc(nData);
  if( aCopy==0 ) return SQLITE_NOMEM;
  memcpy(aCopy, aData, nData);
  sqlite3ValueSetStr(pVal, nData, (char*)aCopy, enc, sqlite3_free);
  return SQLITE_OK;
}

/*
** Deserialize a single record from a buffer in memory. See "RECORD FORMAT"
** for details.
**
** When this function is called, *paChange points to the start of the record
** to deserialize. Assuming no error occurs, *paChange is set to point to

  int rc = SQLITE_OK;

  for(i=0; i<nCol && rc==SQLITE_OK; i++){
    int eType = 0;                /* Type of value (SQLITE_NULL, TEXT etc.) */
    if( abPK && abPK[i]==0 ) continue;
    rc = sessionInputBuffer(pIn, 9);
    if( rc==SQLITE_OK ){
      eType = pIn->aData[pIn->iNext++];
    }

    assert( !apOut || apOut[i]==0 );
    if( eType ){
      if( apOut ){
        apOut[i] = sqlite3ValueNew(0);
        if( !apOut[i] ) rc = SQLITE_NOMEM;
      }
    }

    if( rc==SQLITE_OK ){
      u8 *aVal = &pIn->aData[pIn->iNext];
      if( eType==SQLITE_TEXT || eType==SQLITE_BLOB ){
        int nByte;
        pIn->iNext += sessionVarintGet(aVal, &nByte);
        rc = sessionInputBuffer(pIn, nByte);
        if( apOut && rc==SQLITE_OK ){

          u8 enc = (eType==SQLITE_TEXT ? SQLITE_UTF8 : 0);
          rc = sessionValueSetStr(apOut[i],&pIn->aData[pIn->iNext],nByte,enc);
        }
        pIn->iNext += nByte;
      }
      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
        if( apOut ){
          sqlite3_int64 v = sessionGetI64(aVal);
          if( eType==SQLITE_INTEGER ){

** buffer (i.e. that it can be accessed without any calls to xInput()).
** If successful, SQLITE_OK is returned. Otherwise, an SQLite error code.
** The input pointer is not moved.
*/
static int sessionChangesetBufferTblhdr(SessionInput *pIn, int *pnByte){
  int rc = SQLITE_OK;
  int nCol = 0;
  int nRead = 0;

  rc = sessionInputBuffer(pIn, 9);
  if( rc==SQLITE_OK ){
    nRead += sessionVarintGet(&pIn->aData[pIn->iNext + nRead], &nCol);
    rc = sessionInputBuffer(pIn, nRead+nCol+100);
    nRead += nCol;
  }

  while( rc==SQLITE_OK ){
    while( (pIn->iNext + nRead)<pIn->nData && pIn->aData[pIn->iNext + nRead] ){
      nRead++;
    }
    if( pIn->aData[pIn->iNext + nRead]==0 ) break;
    rc = sessionInputBuffer(pIn, nRead + 100);
  }
  if( pnByte ) *pnByte = nRead+1;
  return rc;
}

/*
** The input pointer currently points to the second byte of a table-header.
** Specifically, to the following:
**
**   + number of columns in table (varint)
**   + array of PK flags (1 byte per column),
**   + table name (nul terminated).
*/
static int sessionChangesetReadTblhdr(sqlite3_changeset_iter *p){
  int rc;
  int nCopy;
  assert( p->rc==SQLITE_OK );

  rc = sessionChangesetBufferTblhdr(&p->in, &nCopy);
  if( rc==SQLITE_OK ){
    int nByte;
    int nVarint;
    nVarint = sessionVarintGet(&p->in.aData[p->in.iNext], &p->nCol);
    nCopy -= nVarint;
    p->in.iNext += nVarint;
    nByte = p->nCol * sizeof(sqlite3_value*) * 2 + nCopy;
    p->tblhdr.nBuf = 0;
    sessionBufferGrow(&p->tblhdr, nByte, &rc);
  }

  if( rc==SQLITE_OK ){
    int iPK = sizeof(sqlite3_value*)*p->nCol*2;
    memset(p->tblhdr.aBuf, 0, iPK);
    memcpy(&p->tblhdr.aBuf[iPK], &p->in.aData[p->in.iNext], nCopy);
    p->in.iNext += nCopy;
  }

  p->apValue = (sqlite3_value**)p->tblhdr.aBuf;
  p->abPK = (u8*)&p->apValue[p->nCol*2];
  p->zTab = (char*)&p->abPK[p->nCol];
  return (p->rc = rc);

  ** remaining data if there are less than 10 bytes available. This is
  ** sufficient either for the 'T' or 'P' byte and the varint that follows
  ** it, or for the two single byte values otherwise. */
  p->rc = sessionInputBuffer(&p->in, 2);
  if( p->rc!=SQLITE_OK ) return p->rc;

  /* If the iterator is already at the end of the changeset, return DONE. */
  if( p->in.iNext>=p->in.nData ){
    return SQLITE_DONE;
  }

  op = p->in.aData[p->in.iNext++];
  if( op=='T' || op=='P' ){
    p->bPatchset = (op=='P');
    if( sessionChangesetReadTblhdr(p) ) return p->rc;
    if( (p->rc = sessionInputBuffer(&p->in, 2)) ) return p->rc;
    op = p->in.aData[p->in.iNext++];
  }

  p->op = op;
  p->bIndirect = p->in.aData[p->in.iNext++];
  if( p->op!=SQLITE_UPDATE && p->op!=SQLITE_DELETE && p->op!=SQLITE_INSERT ){
    return (p->rc = SQLITE_CORRUPT_BKPT);
  }

  if( paRec ){ *paRec = &p->in.aData[p->in.iNext]; }

  /* If this is an UPDATE or DELETE, read the old.* record. */
  if( p->op!=SQLITE_INSERT && (p->bPatchset==0 || p->op==SQLITE_DELETE) ){
    u8 *abPK = p->bPatchset ? p->abPK : 0;
    p->rc = sessionReadRecord(&p->in, p->nCol, abPK, paRec?0:p->apValue);
    if( p->rc!=SQLITE_OK ) return p->rc;
  }

  /* If this is an INSERT or UPDATE, read the new.* record. */
  if( p->op!=SQLITE_DELETE ){
    sqlite3_value **apOut = (paRec ? 0 : &p->apValue[p->nCol]);
    p->rc = sessionReadRecord(&p->in, p->nCol, 0, apOut);
    if( p->rc!=SQLITE_OK ) return p->rc;
  }

  if( pnRec ){
    *pnRec = (int)(&p->in.aData[p->in.iNext] - *paRec);
  }else if( p->bPatchset && p->op==SQLITE_UPDATE ){
    /* If this is an UPDATE that is part of a patchset, then all PK and
    ** modified fields are present in the new.* record. The old.* record
    ** is currently completely empty. This block shifts the PK fields from
    ** new.* to old.*, to accommodate the code that reads these arrays.  */
    int i;
    for(i=0; i<p->nCol; i++){

int sqlite3changeset_finalize(sqlite3_changeset_iter *p){
  int i;                          /* Used to iterate through p->apValue[] */
  int rc = p->rc;                 /* Return code */
  if( p->apValue ){
    for(i=0; i<p->nCol*2; i++) sqlite3ValueFree(p->apValue[i]);
  }
  sqlite3_free(p->tblhdr.aBuf);
  sqlite3_free(p->in.buf.aBuf);
  sqlite3_free(p);
  return rc;
}

/*
** Invert a changeset object.
*/

  /* Zero the output variables in case an error occurs. */
  *ppInverted = 0;
  *pnInverted = 0;
  if( nChangeset==0 ) return SQLITE_OK;

  /* Set up the input stream */
  memset(&sInput, 0, sizeof(SessionInput));
  sInput.nData = nChangeset;
  sInput.aData = (u8*)pChangeset;

  aOut = (u8 *)sqlite3_malloc(nChangeset);
  if( !aOut ) return SQLITE_NOMEM;
  aIn = (u8 *)pChangeset;

  i = 0;
  while( i<nChangeset ){
    u8 eType;
    if( (rc = sessionInputBuffer(&sInput, 2)) ) goto finished_invert;
    eType = sInput.aData[sInput.iNext];
    switch( eType ){
      case 'T': {
        /* A 'table' record consists of:
        **
        **   * A constant 'T' character,
        **   * Number of columns in said table (a varint),
        **   * An array of nCol bytes (sPK),
        **   * A nul-terminated table name.
        */
        int nByte;
        int nVarint;
        int iNext = sInput.iNext;
        sInput.iNext++;
        if( (rc = sessionChangesetBufferTblhdr(&sInput, &nByte)) ){
          goto finished_invert;
        }
        nVarint = sessionVarintGet(&sInput.aData[iNext+1], &nCol);
        sPK.nBuf = 0;
        sessionAppendBlob(&sPK, &sInput.aData[iNext+1+nVarint], nCol, &rc);
        if( rc ) goto finished_invert;
        sInput.iNext += nByte;
        memcpy(&aOut[i], &sInput.aData[iNext], nByte+1);
        i += nByte+1;
        sqlite3_free(apVal);
        apVal = 0;
        abPK = sPK.aBuf;
        break;
      }

      case SQLITE_INSERT:
      case SQLITE_DELETE: {
        int iStart;
        int nByte;
        sInput.iNext += 2;
        iStart = sInput.iNext;
        sessionReadRecord(&sInput, nCol, 0, 0);
        aOut[i] = (eType==SQLITE_DELETE ? SQLITE_INSERT : SQLITE_DELETE);
        aOut[i+1] = aIn[i+1];               /* indirect-flag */
        nByte = sInput.iNext - iStart;
        memcpy(&aOut[i+2], &sInput.aData[iStart], nByte);
        i += 2 + nByte;
        break;
      }

      case SQLITE_UPDATE: {
        int iCol;
        int nWrite = 0;

        if( 0==apVal ){
          apVal = (sqlite3_value **)sqlite3_malloc(sizeof(apVal[0])*nCol*2);
          if( 0==apVal ){
            rc = SQLITE_NOMEM;
            goto finished_invert;
          }
          memset(apVal, 0, sizeof(apVal[0])*nCol*2);
        }

        /* Write the header for the new UPDATE change. Same as the original. */
        aOut[i] = SQLITE_UPDATE;
        aOut[i+1] = sInput.aData[sInput.iNext+1];
        nWrite = 2;

        /* Read the old.* and new.* records for the update change. */
        sInput.iNext += 2;
        rc = sessionReadRecord(&sInput, nCol, 0, &apVal[0]);
        if( rc==SQLITE_OK ){
          rc = sessionReadRecord(&sInput, nCol, 0, &apVal[nCol]);

        i += nWrite;
        assert( i==sInput.iNext );
        break;
      }

      default:
        rc = SQLITE_CORRUPT_BKPT;
        goto finished_invert;
    }
  }

  assert( rc==SQLITE_OK );
  *pnInverted = nChangeset;
  *ppInverted = (void *)aOut;

    }
  }

  return rc;
}

/*
** Argument pIter is a changeset iterator that has been initialized, but
** not yet passed to sqlite3changeset_next(). This function applies the 
** changeset to the main database attached to handle "db". The supplied
** conflict handler callback is invoked to resolve any conflicts encountered
** while applying the change.
*/
static int sessionChangesetApply(
  sqlite3 *db,                    /* Apply change to "main" db of this handle */

  sqlite3_changeset_iter *pIter,  /* Changeset to apply */
  int(*xFilter)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    const char *zTab              /* Table name */
  ),
  int(*xConflict)(
    void *pCtx,                   /* Copy of fifth arg to _apply() */
    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
  ),
  void *pCtx                      /* First argument passed to xConflict */
){
  int schemaMismatch = 0;

  int rc;                         /* Return code */
  const char *zTab = 0;           /* Name of current table */
  int nTab = 0;                   /* Result of sqlite3Strlen30(zTab) */
  SessionApplyCtx sApply;         /* changeset_apply() context object */

  assert( xConflict!=0 );

  memset(&sApply, 0, sizeof(sApply));



  sqlite3_mutex_enter(sqlite3_db_mutex(db));
  rc = sqlite3_exec(db, "SAVEPOINT changeset_apply", 0, 0, 0);
  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(db, "PRAGMA defer_foreign_keys = 1", 0, 0, 0);
  }
  while( rc==SQLITE_OK && SQLITE_ROW==sqlite3changeset_next(pIter) ){
    int nCol;

  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);
  sqlite3_finalize(sApply.pSelect);
  sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
  sqlite3_mutex_leave(sqlite3_db_mutex(db));
  return rc;
}

/*
** Apply the changeset passed via pChangeset/nChangeset to the main database
** attached to handle "db". Invoke the supplied conflict handler callback
** to resolve any conflicts encountered while applying the change.
*/
int sqlite3changeset_apply(
  sqlite3 *db,                    /* Apply change to "main" db of this handle */
  int nChangeset,                 /* Size of changeset in bytes */
  void *pChangeset,               /* Changeset blob */
  int(*xFilter)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    const char *zTab              /* Table name */
  ),
  int(*xConflict)(
    void *pCtx,                   /* Copy of fifth arg to _apply() */
    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
  ),
  void *pCtx                      /* First argument passed to xConflict */
){
  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */  
  int rc = sqlite3changeset_start(&pIter, nChangeset, pChangeset);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetApply(db, pIter, xFilter, xConflict, pCtx);
  }
  return rc;
}

/*
** Apply the changeset passed via xInput/pIn to the main database
** attached to handle "db". Invoke the supplied conflict handler callback
** to resolve any conflicts encountered while applying the change.
*/
int sqlite3changeset_apply_str(
  sqlite3 *db,                    /* Apply change to "main" db of this handle */
  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
  void *pIn,                                          /* First arg for xInput */
  int(*xFilter)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    const char *zTab              /* Table name */
  ),
  int(*xConflict)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
  ),
  void *pCtx                      /* First argument passed to xConflict */
){
  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */  
  int rc = sqlite3changeset_start_str(&pIter, xInput, pIn);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetApply(db, pIter, xFilter, xConflict, pCtx);
  }
  return rc;
}

/*
** This function is called to merge two changes to the same row together as
** part of an sqlite3changeset_concat() operation. A new change object is
** allocated and a pointer to it stored in *ppNew.
*/
static int sessionChangeMerge(

** SQLite error code returned.
*/
int sqlite3changeset_apply(
  sqlite3 *db,                    /* Apply change to "main" db of this handle */
  int nChangeset,                 /* Size of changeset in bytes */
  void *pChangeset,               /* Changeset blob */
  int(*xFilter)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    const char *zTab              /* Table name */
  ),
  int(*xConflict)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
  ),
  void *pCtx                      /* First argument passed to xConflict */
);

/*
** This function is similar to sqlite3changeset_apply(), except that instead
** of reading data from a single buffer, it requests it one chunk at a time
** from the application by invoking the supplied xInput() callback.
**
** See the documentation for sqlite3changeset_start_str() for a description
** of how the xInput callback should be implemented.
*/
int sqlite3changeset_apply_str(
  sqlite3 *db,                    /* Apply change to "main" db of this handle */
  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
  void *pIn,                                          /* First arg for xInput */
  int(*xFilter)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    const char *zTab              /* Table name */
  ),
  int(*xConflict)(
    void *pCtx,                   /* Copy of sixth arg to _apply() */
    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
    sqlite3_changeset_iter *p     /* Handle describing change and conflict */

typedef struct TestSession TestSession;
struct TestSession {
  sqlite3_session *pSession;
  Tcl_Interp *interp;
  Tcl_Obj *pFilterScript;
};

typedef struct TestStreamInput TestStreamInput;
struct TestStreamInput {
  int nStream;                    /* Maximum chunk size */
  unsigned char *aData;           /* Pointer to buffer containing data */
  int nData;                      /* Size of buffer aData in bytes */
  int iData;                      /* Bytes of data already read by sessions */
};

#define SESSION_STREAM_TCL_VAR "sqlite3session_streams"

/*
** Attempt to find the global variable zVar within interpreter interp
** and extract an integer value from it. Return this value.
**
** If the named variable cannot be found, or if it cannot be interpreted
** as a integer, return 0.
*/
static int test_tcl_integer(Tcl_Interp *interp, const char *zVar){
  Tcl_Obj *pObj;
  int iVal = 0;
  pObj = Tcl_ObjGetVar2(interp, Tcl_NewStringObj(zVar, -1), 0, TCL_GLOBAL_ONLY);
  if( pObj ) Tcl_GetIntFromObj(0, pObj, &iVal);
  return iVal;
}

static int test_session_error(Tcl_Interp *interp, int rc){
  extern const char *sqlite3ErrName(int);
  Tcl_SetObjResult(interp, Tcl_NewStringObj(sqlite3ErrName(rc), -1));
  return TCL_ERROR;
}

      }
      break;
    }

    case 7:        /* patchset */
    case 1: {      /* changeset */
      TestSessionsBlob o = {0, 0};
      if( test_tcl_integer(interp, SESSION_STREAM_TCL_VAR) ){
        void *pCtx = (void*)&o;
        if( iSub==7 ){
          rc = sqlite3session_patchset_str(pSession, testSessionsOutput, pCtx);
        }else{
          rc = sqlite3session_changeset_str(pSession, testSessionsOutput, pCtx);
        }
      }else{

  }

  if( eConf==SQLITE_CHANGESET_DATA ){
    return SQLITE_CHANGESET_REPLACE;
  }
  return SQLITE_CHANGESET_OMIT;
}

static int testStreamInput(
  void *pCtx,                     /* Context pointer */
  void *pData,                    /* Buffer to populate */
  int *pnData                     /* IN/OUT: Bytes requested/supplied */
){
  TestStreamInput *p = (TestStreamInput*)pCtx;
  int nReq = *pnData;             /* Bytes of data requested */
  int nRem = p->nData - p->iData; /* Bytes of data available */
  int nRet = p->nStream;          /* Bytes actually returned */

  if( nRet>nReq ) nRet = nReq;
  if( nRet>nRem ) nRet = nRem;

  assert( nRet>=0 );
  if( nRet>0 ){
    memcpy(pData, &p->aData[p->iData], nRet);
    p->iData += nRet;
  }

  *pnData = nRet;
  return SQLITE_OK;
}


/*
** sqlite3changeset_apply DB CHANGESET CONFLICT-SCRIPT ?FILTER-SCRIPT?
*/
static int test_sqlite3changeset_apply(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3 *db;                    /* Database handle */
  Tcl_CmdInfo info;               /* Database Tcl command (objv[1]) info */
  int rc;                         /* Return code from changeset_invert() */
  void *pChangeset;               /* Buffer containing changeset */
  int nChangeset;                 /* Size of buffer aChangeset in bytes */
  TestConflictHandler ctx;
  TestStreamInput sStr;

  memset(&sStr, 0, sizeof(sStr));
  sStr.nStream = test_tcl_integer(interp, SESSION_STREAM_TCL_VAR);

  if( objc!=4 && objc!=5 ){
    Tcl_WrongNumArgs(interp, 1, objv, 
        "DB CHANGESET CONFLICT-SCRIPT ?FILTER-SCRIPT?"
    );
    return TCL_ERROR;
  }
  if( 0==Tcl_GetCommandInfo(interp, Tcl_GetString(objv[1]), &info) ){
    Tcl_AppendResult(interp, "no such handle: ", Tcl_GetString(objv[2]), 0);
    return TCL_ERROR;
  }
  db = *(sqlite3 **)info.objClientData;
  pChangeset = (void *)Tcl_GetByteArrayFromObj(objv[2], &nChangeset);
  ctx.pConflictScript = objv[3];
  ctx.pFilterScript = objc==5 ? objv[4] : 0;
  ctx.interp = interp;

  if( sStr.nStream==0 ){
    rc = sqlite3changeset_apply(db, nChangeset, pChangeset, 
        (objc==5) ? test_filter_handler : 0, test_conflict_handler, (void *)&ctx
    );
  }else{
    sStr.aData = (unsigned char*)pChangeset;
    sStr.nData = nChangeset;
    rc = sqlite3changeset_apply_str(db, testStreamInput, (void*)&sStr,
        (objc==5) ? test_filter_handler : 0, test_conflict_handler, (void *)&ctx
    );
  }

  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc);
  }
  Tcl_ResetResult(interp);
  return TCL_OK;
}

  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;                         /* Return code from changeset_invert() */
  void *aChangeset;               /* Input changeset */
  int nChangeset;                 /* Size of buffer aChangeset in bytes */
  void *aOut;                     /* Output changeset */
  int nOut;                       /* Size of buffer aOut in bytes */

  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "CHANGESET");
    return TCL_ERROR;
  }
  aChangeset = (void *)Tcl_GetByteArrayFromObj(objv[1], &nChangeset);

  rc = sqlite3changeset_invert(nChangeset, aChangeset, &nOut, &aOut);
  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc);
  }
  Tcl_SetObjResult(interp, Tcl_NewByteArrayObj((unsigned char *)aOut, nOut));
  sqlite3_free(aOut);
  return TCL_OK;
}

*/
static int test_sqlite3session_foreach(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  void *pChangeset;
  int nChangeset;
  sqlite3_changeset_iter *pIter;
  int rc;
  Tcl_Obj *pVarname;
  Tcl_Obj *pCS;
  Tcl_Obj *pScript;
  int isCheckNext = 0;

  TestStreamInput sStr;
  memset(&sStr, 0, sizeof(sStr));

  if( objc>1 ){
    char *zOpt = Tcl_GetString(objv[1]);
    isCheckNext = (strcmp(zOpt, "-next")==0);
  }
  if( objc!=4+isCheckNext ){
    Tcl_WrongNumArgs(interp, 1, objv, "?-next? VARNAME CHANGESET SCRIPT");
    return TCL_ERROR;
  }

  pVarname = objv[1+isCheckNext];
  pCS = objv[2+isCheckNext];
  pScript = objv[3+isCheckNext];

  pChangeset = (void *)Tcl_GetByteArrayFromObj(pCS, &nChangeset);
  sStr.nStream = test_tcl_integer(interp, SESSION_STREAM_TCL_VAR);
  if( sStr.nStream==0 ){
    rc = sqlite3changeset_start(&pIter, nChangeset, pChangeset);
  }else{
    sStr.aData = (unsigned char*)pChangeset;
    sStr.nData = nChangeset;
    rc = sqlite3changeset_start_str(&pIter, testStreamInput, (void*)&sStr);
  }
  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc);
  }

  while( SQLITE_ROW==sqlite3changeset_next(pIter) ){
    int nCol;                     /* Number of columns in table */
    int nCol2;                    /* Number of columns in table */

source $testdir/permutations.test

ifcapable session {
  # First run tests with sqlite3_extended_error_codes() set, then
  # again with it clear.
  run_test_suite session_eec
  run_test_suite session
  run_test_suite session_str
}

finish_test