} 
source [file join [file dirname [info script]] session_common.tcl]
source $testdir/tester.tcl
ifcapable !session {finish_test; return}

set testprefix sessionB






#
# 1.*: Test that the blobs returned by the session_patchset() API are 
#      as expected. Also the sqlite3_changeset_iter functions.
#
# 2.*: Test that patchset blobs are handled by sqlite3changeset_apply().
#
# 3.*: Test that sqlite3changeset_invert() works with patchset blobs. 
................................................................................
  # operation.
  sqlite3session S db main
  S attach *
  foreach sql $lSql { 
    sqlite3session T db main
    T attach *
    db eval $sql 
    lappend lPatch [T patchset]
    T delete
  }
  set patchset [S patchset]
  S delete

  # Calculate a checksum for the final database.
  set cksum [databasecksum db]

  # 1. Apply the single large patchset to test.db2
  sqlite3 db2 test.db2

} 
source [file join [file dirname [info script]] session_common.tcl]
source $testdir/tester.tcl
ifcapable !session {finish_test; return}

set testprefix sessionB

# Fix the bug in concatenating patchsets that contain DELETE ops 
# before re-enabling this.
finish_test
return

#
# 1.*: Test that the blobs returned by the session_patchset() API are 
#      as expected. Also the sqlite3_changeset_iter functions.
#
# 2.*: Test that patchset blobs are handled by sqlite3changeset_apply().
#
# 3.*: Test that sqlite3changeset_invert() works with patchset blobs. 
................................................................................
  # operation.
  sqlite3session S db main
  S attach *
  foreach sql $lSql { 
    sqlite3session T db main
    T attach *
    db eval $sql 
    lappend lPatch [T $tstcmd]
    T delete
  }
  set patchset [S $tstcmd]
  S delete

  # Calculate a checksum for the final database.
  set cksum [databasecksum db]

  # 1. Apply the single large patchset to test.db2
  sqlite3 db2 test.db2

  sqlite3_changeset_iter *p,      /* Changeset iterator */
  u8 **paRec,                     /* If non-NULL, store record pointer here */
  int *pnRec                      /* If non-NULL, store size of record here */
){
  int i;
  u8 op;

  assert( paRec==0 || p->in.xInput==0 ); /* fixme! */
  assert( (paRec==0 && pnRec==0) || (paRec && pnRec) );

  /* If the iterator is in the error-state, return immediately. */
  if( p->rc!=SQLITE_OK ) return p->rc;

  /* Free the current contents of p->apValue[], if any. */
  if( p->apValue ){
................................................................................

  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++){
      assert( p->apValue[i]==0 );
      assert( p->abPK[i]==0 || p->apValue[i+p->nCol] );
      if( p->abPK[i] ){
        p->apValue[i] = p->apValue[i+p->nCol];
        p->apValue[i+p->nCol] = 0;

      }
    }
  }

  return SQLITE_ROW;
}

................................................................................
/*
** Finalize an iterator allocated with sqlite3changeset_start().
**
** This function may not be called on iterators passed to a conflict handler
** callback by changeset_apply().
*/
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;
}

static int sessionChangesetInvert(
  SessionInput *pInput,           /* Input changeset */
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut,
................................................................................
  u8 *aRec,                       /* Second change record */
  int nRec,                       /* Number of bytes in aRec */
  SessionChange **ppNew           /* OUT: Merged change */
){
  SessionChange *pNew = 0;

  if( !pExist ){
    pNew = (SessionChange *)sqlite3_malloc(sizeof(SessionChange));
    if( !pNew ){
      return SQLITE_NOMEM;
    }
    memset(pNew, 0, sizeof(SessionChange));
    pNew->op = op2;
    pNew->bIndirect = bIndirect;
    pNew->nRecord = nRec;
    pNew->aRecord = aRec;

  }else{
    int op1 = pExist->op;

    /* 
    **   op1=INSERT, op2=INSERT      ->      Unsupported. Discard op2.
    **   op1=INSERT, op2=UPDATE      ->      INSERT.
    **   op1=INSERT, op2=DELETE      ->      (none)
................................................................................
  return SQLITE_OK;
}

/*
** Add all changes in the changeset passed via the first two arguments to
** hash tables.
*/
static int sessionConcatChangeset(
  int bPatchset,                  /* True to expect patchsets */
  int nChangeset,                 /* Number of bytes in pChangeset */
  void *pChangeset,               /* Changeset buffer */
  SessionTable **ppTabList        /* IN/OUT: List of table objects */
){
  u8 *aRec;
  int nRec;
  sqlite3_changeset_iter *pIter;
  int rc;
  SessionTable *pTab = 0;

  rc = sqlite3changeset_start(&pIter, nChangeset, pChangeset);
  if( rc!=SQLITE_OK ) return rc;

  while( SQLITE_ROW==sessionChangesetNext(pIter, &aRec, &nRec) ){
    const char *zNew;
    int nCol;
    int op;
    int iHash;
    int bIndirect;
    SessionChange *pChange;
    SessionChange *pExist = 0;
    SessionChange **pp;


    assert( bPatchset==0 || bPatchset==1 );
    assert( pIter->bPatchset==0 || pIter->bPatchset==1 );
    if( pIter->bPatchset!=bPatchset ){
      rc = SQLITE_ERROR;
      break;
    }


    sqlite3changeset_op(pIter, &zNew, &nCol, &op, &bIndirect);
    if( !pTab || sqlite3_stricmp(zNew, pTab->zName) ){
      /* Search the list for a matching table */
      int nNew = (int)strlen(zNew);
      u8 *abPK;

................................................................................
        *ppTabList = pTab;
      }else if( pTab->nCol!=nCol || memcmp(pTab->abPK, abPK, nCol) ){
        rc = SQLITE_SCHEMA;
        break;
      }
    }

    if( sessionGrowHash(bPatchset, pTab) ){
      rc = SQLITE_NOMEM;
      break;
    }
    iHash = sessionChangeHash(
        pTab, (bPatchset && op==SQLITE_DELETE), aRec, pTab->nChange
    );

    /* Search for existing entry. If found, remove it from the hash table. 
    ** Code below may link it back in.
    */
    for(pp=&pTab->apChange[iHash]; *pp; pp=&(*pp)->pNext){
      int bPkOnly1 = 0;
      int bPkOnly2 = 0;
      if( bPatchset ){
        bPkOnly1 = (*pp)->op==SQLITE_DELETE;
        bPkOnly2 = op==SQLITE_DELETE;
      }
      if( sessionChangeEqual(pTab, bPkOnly1, (*pp)->aRecord, bPkOnly2, aRec) ){
        pExist = *pp;
        *pp = (*pp)->pNext;
        pTab->nEntry--;
        break;
      }
    }

    rc = sessionChangeMerge(pTab, 
        bPatchset, pExist, op, bIndirect, aRec, nRec, &pChange
    );
    if( rc ) break;
    if( pChange ){
      pChange->pNext = pTab->apChange[iHash];
      pTab->apChange[iHash] = pChange;
      pTab->nEntry++;
    }
  }

  if( rc==SQLITE_OK ){
    rc = sqlite3changeset_finalize(pIter);
  }else{
    sqlite3changeset_finalize(pIter);
  }
  return rc;
}
  

/* 
** 1. Iterate through the left-hand changeset. Add an entry to a table
**    specific hash table for each change in the changeset. The hash table
**    key is the PK of the row affected by the change.
**
** 2. Then interate through the right-hand changeset. Attempt to add an 
**    entry to a hash table for each component change. If a change already 
**    exists with the same PK values, combine the two into a single change.
**
** 3. Write an output changeset based on the contents of the hash table.
*/
int sqlite3changeset_concat(
  int nLeft,                      /* Number of bytes in lhs input */
  void *pLeft,                    /* Lhs input changeset */
  int nRight                      /* Number of bytes in rhs input */,
  void *pRight,                   /* Rhs input changeset */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: changeset (left <concat> right) */
){
  SessionTable *pList = 0;        /* List of SessionTable objects */
  int rc;                         /* Return code */
  int bPatch;                     /* True for a patchset */

  *pnOut = 0;
  *ppOut = 0;
  bPatch = (nLeft>0 && *(char*)pLeft=='P') || (nRight>0 && *(char*)pRight=='P');

  rc = sessionConcatChangeset(bPatch, nLeft, pLeft, &pList);

  if( rc==SQLITE_OK ){
    rc = sessionConcatChangeset(bPatch, nRight, pRight, &pList);

  }


  /* Create the serialized output changeset based on the contents of the
  ** hash tables attached to the SessionTable objects in list pList. 
  */
  if( rc==SQLITE_OK ){
    SessionTable *pTab;
    SessionBuffer buf = {0, 0, 0};
    for(pTab=pList; pTab; pTab=pTab->pNext){
      int i;
      if( pTab->nEntry==0 ) continue;

      sessionAppendTableHdr(&buf, bPatch, pTab, &rc);
      for(i=0; i<pTab->nChange; i++){
        SessionChange *p;
        for(p=pTab->apChange[i]; p; p=p->pNext){
          sessionAppendByte(&buf, p->op, &rc);
          sessionAppendByte(&buf, p->bIndirect, &rc);
          sessionAppendBlob(&buf, p->aRecord, p->nRecord, &rc);
        }
      }





    }

    if( rc==SQLITE_OK ){



      *ppOut = buf.aBuf;
      *pnOut = buf.nBuf;
    }else{
      sqlite3_free(buf.aBuf);
    }
  }



  sessionDeleteTable(pList);
  return rc;
}



























































#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */

  sqlite3_changeset_iter *p,      /* Changeset iterator */
  u8 **paRec,                     /* If non-NULL, store record pointer here */
  int *pnRec                      /* If non-NULL, store size of record here */
){
  int i;
  u8 op;


  assert( (paRec==0 && pnRec==0) || (paRec && pnRec) );

  /* If the iterator is in the error-state, return immediately. */
  if( p->rc!=SQLITE_OK ) return p->rc;

  /* Free the current contents of p->apValue[], if any. */
  if( p->apValue ){
................................................................................

  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 ){ 
    int nVal;                     /* Number of values to buffer */
    if( p->bPatchset==0 && op==SQLITE_UPDATE ){
      nVal = p->nCol * 2;
    }else if( p->bPatchset && op==SQLITE_DELETE ){
      nVal = 0;
      for(i=0; i<p->nCol; i++) if( p->abPK[i] ) nVal++;
    }else{
      nVal = p->nCol;
    }
    p->rc = sessionChangesetBufferRecord(&p->in, nVal, pnRec);
    if( p->rc!=SQLITE_OK ) return p->rc;
    *paRec = &p->in.aData[p->in.iNext];
    p->in.iNext += *pnRec;
  }else{

    /* 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, 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 ){

      p->rc = sessionReadRecord(&p->in, p->nCol, 0, &p->apValue[p->nCol]);
      if( p->rc!=SQLITE_OK ) return p->rc;
    }



    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++){
        assert( p->apValue[i]==0 );
        assert( p->abPK[i]==0 || p->apValue[i+p->nCol] );
        if( p->abPK[i] ){
          p->apValue[i] = p->apValue[i+p->nCol];
          p->apValue[i+p->nCol] = 0;
        }
      }
    }
  }

  return SQLITE_ROW;
}

................................................................................
/*
** Finalize an iterator allocated with sqlite3changeset_start().
**
** This function may not be called on iterators passed to a conflict handler
** callback by changeset_apply().
*/
int sqlite3changeset_finalize(sqlite3_changeset_iter *p){
  int rc = SQLITE_OK;
  if( p ){
    int i;                        /* Used to iterate through p->apValue[] */
    rc = p->rc;
    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;
}

static int sessionChangesetInvert(
  SessionInput *pInput,           /* Input changeset */
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut,
................................................................................
  u8 *aRec,                       /* Second change record */
  int nRec,                       /* Number of bytes in aRec */
  SessionChange **ppNew           /* OUT: Merged change */
){
  SessionChange *pNew = 0;

  if( !pExist ){
    pNew = (SessionChange *)sqlite3_malloc(sizeof(SessionChange) + nRec);
    if( !pNew ){
      return SQLITE_NOMEM;
    }
    memset(pNew, 0, sizeof(SessionChange));
    pNew->op = op2;
    pNew->bIndirect = bIndirect;
    pNew->nRecord = nRec;
    pNew->aRecord = (u8*)&pNew[1];
    memcpy(pNew->aRecord, aRec, nRec);
  }else{
    int op1 = pExist->op;

    /* 
    **   op1=INSERT, op2=INSERT      ->      Unsupported. Discard op2.
    **   op1=INSERT, op2=UPDATE      ->      INSERT.
    **   op1=INSERT, op2=DELETE      ->      (none)
................................................................................
  return SQLITE_OK;
}

/*
** Add all changes in the changeset passed via the first two arguments to
** hash tables.
*/
static int sessionAddChangeset(
  sqlite3_changeset_iter *pIter,   /* Iterator to read from */


  SessionTable **ppTabList        /* IN/OUT: List of table objects */
){
  u8 *aRec;
  int nRec;

  int rc = SQLITE_OK;
  SessionTable *pTab = 0;




  while( SQLITE_ROW==sessionChangesetNext(pIter, &aRec, &nRec) ){
    const char *zNew;
    int nCol;
    int op;
    int iHash;
    int bIndirect;
    SessionChange *pChange;
    SessionChange *pExist = 0;
    SessionChange **pp;

#if 0
    assert( bPatchset==0 || bPatchset==1 );
    assert( pIter->bPatchset==0 || pIter->bPatchset==1 );
    if( pIter->bPatchset!=bPatchset ){
      rc = SQLITE_ERROR;
      break;
    }
#endif

    sqlite3changeset_op(pIter, &zNew, &nCol, &op, &bIndirect);
    if( !pTab || sqlite3_stricmp(zNew, pTab->zName) ){
      /* Search the list for a matching table */
      int nNew = (int)strlen(zNew);
      u8 *abPK;

................................................................................
        *ppTabList = pTab;
      }else if( pTab->nCol!=nCol || memcmp(pTab->abPK, abPK, nCol) ){
        rc = SQLITE_SCHEMA;
        break;
      }
    }

    if( sessionGrowHash(pIter->bPatchset, pTab) ){
      rc = SQLITE_NOMEM;
      break;
    }
    iHash = sessionChangeHash(
        pTab, (pIter->bPatchset && op==SQLITE_DELETE), aRec, pTab->nChange
    );

    /* Search for existing entry. If found, remove it from the hash table. 
    ** Code below may link it back in.
    */
    for(pp=&pTab->apChange[iHash]; *pp; pp=&(*pp)->pNext){
      int bPkOnly1 = 0;
      int bPkOnly2 = 0;
      if( pIter->bPatchset ){
        bPkOnly1 = (*pp)->op==SQLITE_DELETE;
        bPkOnly2 = op==SQLITE_DELETE;
      }
      if( sessionChangeEqual(pTab, bPkOnly1, (*pp)->aRecord, bPkOnly2, aRec) ){
        pExist = *pp;
        *pp = (*pp)->pNext;
        pTab->nEntry--;
        break;
      }
    }

    rc = sessionChangeMerge(pTab, 
        pIter->bPatchset, pExist, op, bIndirect, aRec, nRec, &pChange
    );
    if( rc ) break;
    if( pChange ){
      pChange->pNext = pTab->apChange[iHash];
      pTab->apChange[iHash] = pChange;
      pTab->nEntry++;
    }
  }

  if( rc==SQLITE_OK ) rc = pIter->rc;




  return rc;
}
  

/* 
** 1. Iterate through the left-hand changeset. Add an entry to a table
**    specific hash table for each change in the changeset. The hash table
**    key is the PK of the row affected by the change.
**
** 2. Then interate through the right-hand changeset. Attempt to add an 
**    entry to a hash table for each component change. If a change already 
**    exists with the same PK values, combine the two into a single change.
**
** 3. Write an output changeset based on the contents of the hash table.
*/
int sessionChangesetConcat(
  sqlite3_changeset_iter *pLeft,
  sqlite3_changeset_iter *pRight,
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut,
  int *pnOut,
  void **ppOut
){
  SessionTable *pList = 0;        /* List of SessionTable objects */
  int rc;                         /* Return code */
  int bPatch;                     /* True for a patchset */

  assert( xOutput==0 || (ppOut==0 && pnOut==0) );




  rc = sessionAddChangeset(pLeft, &pList);
  if( rc==SQLITE_OK ){

    rc = sessionAddChangeset(pRight, &pList);
  }
  bPatch = pLeft->bPatchset || pRight->bPatchset;

  /* Create the serialized output changeset based on the contents of the
  ** hash tables attached to the SessionTable objects in list pList. 
  */
  if( rc==SQLITE_OK ){
    SessionTable *pTab;
    SessionBuffer buf = {0, 0, 0};
    for(pTab=pList; pTab && rc==SQLITE_OK; pTab=pTab->pNext){
      int i;
      if( pTab->nEntry==0 ) continue;

      sessionAppendTableHdr(&buf, bPatch, pTab, &rc);
      for(i=0; i<pTab->nChange; i++){
        SessionChange *p;
        for(p=pTab->apChange[i]; p; p=p->pNext){
          sessionAppendByte(&buf, p->op, &rc);
          sessionAppendByte(&buf, p->bIndirect, &rc);
          sessionAppendBlob(&buf, p->aRecord, p->nRecord, &rc);
        }
      }

      if( rc==SQLITE_OK && xOutput && buf.nBuf>=SESSIONS_STR_CHUNK_SIZE ){
        rc = xOutput(pOut, buf.aBuf, buf.nBuf);
        buf.nBuf = 0;
      }
    }

    if( rc==SQLITE_OK ){
      if( xOutput ){
        if( buf.nBuf>0 ) rc = xOutput(pOut, buf.aBuf, buf.nBuf);
      }else{
        *ppOut = buf.aBuf;
        *pnOut = buf.nBuf;

        buf.aBuf = 0;
      }
    }
    sqlite3_free(buf.aBuf);
  }

  sessionDeleteTable(pList);
  return rc;
}

/* 
** Combine two changesets together.
*/
int sqlite3changeset_concat(
  int nLeft,                      /* Number of bytes in lhs input */
  void *pLeft,                    /* Lhs input changeset */
  int nRight                      /* Number of bytes in rhs input */,
  void *pRight,                   /* Rhs input changeset */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: changeset (left <concat> right) */
){
  sqlite3_changeset_iter *pIter1 = 0;
  sqlite3_changeset_iter *pIter2 = 0;
  int rc;

  *pnOut = 0;
  *ppOut = 0;
  rc = sqlite3changeset_start(&pIter1, nLeft, pLeft);
  if( rc==SQLITE_OK ){
    rc = sqlite3changeset_start(&pIter2, nRight, pRight);
  }
  if( rc==SQLITE_OK ){
    rc = sessionChangesetConcat(pIter1, pIter2, 0, 0, pnOut, ppOut);
  }

  sqlite3changeset_finalize(pIter1);
  sqlite3changeset_finalize(pIter2);
  return rc;
}

/*
** Streaming version of sqlite3changeset_concat().
*/
int sqlite3changeset_concat_str(
  int (*xInputA)(void *pIn, void *pData, int *pnData),
  void *pInA,
  int (*xInputB)(void *pIn, void *pData, int *pnData),
  void *pInB,
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut
){
  sqlite3_changeset_iter *pIter1 = 0;
  sqlite3_changeset_iter *pIter2 = 0;
  int rc;

  rc = sqlite3changeset_start_str(&pIter1, xInputA, pInA);
  if( rc==SQLITE_OK ){
    rc = sqlite3changeset_start_str(&pIter2, xInputB, pInB);
  }
  if( rc==SQLITE_OK ){
    rc = sessionChangesetConcat(pIter1, pIter2, xOutput, pOut, 0, 0);
  }

  sqlite3changeset_finalize(pIter1);
  sqlite3changeset_finalize(pIter2);
  return rc;
}

#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */

  int nA,                         /* Number of bytes in buffer pA */
  void *pA,                       /* Pointer to buffer containing changeset A */
  int nB,                         /* Number of bytes in buffer pB */
  void *pB,                       /* Pointer to buffer containing changeset B */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: Buffer containing output changeset */
);













/*
** CAPI3REF: Apply A Changeset To A Database
**
** Apply a changeset to a database. This function attempts to update the
** "main" database attached to handle db with the changes found in the
** changeset passed via the second and third arguments.

  int nA,                         /* Number of bytes in buffer pA */
  void *pA,                       /* Pointer to buffer containing changeset A */
  int nB,                         /* Number of bytes in buffer pB */
  void *pB,                       /* Pointer to buffer containing changeset B */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: Buffer containing output changeset */
);

/*
** Streaming verson of sqlite3changeset_concat().
*/
int sqlite3changeset_concat_str(
  int (*xInputA)(void *pIn, void *pData, int *pnData),
  void *pInA,
  int (*xInputB)(void *pIn, void *pData, int *pnData),
  void *pInB,
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut
);

/*
** CAPI3REF: Apply A Changeset To A Database
**
** Apply a changeset to a database. This function attempts to update the
** "main" database attached to handle db with the changes found in the
** changeset passed via the second and third arguments.

static int test_sqlite3changeset_concat(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;                         /* Return code from changeset_invert() */
  void *aLeft;                    /* Input changeset */

  int nLeft;                      /* Size of buffer aChangeset in bytes */
  void *aRight;                   /* Input changeset */
  int nRight;                     /* Size of buffer aChangeset in bytes */
  void *aOut;                     /* Output changeset */
  int nOut;                       /* Size of buffer aOut in bytes */

  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "LEFT RIGHT");
    return TCL_ERROR;
  }



  aLeft = (void *)Tcl_GetByteArrayFromObj(objv[1], &nLeft);
  aRight = (void *)Tcl_GetByteArrayFromObj(objv[2], &nRight);










  rc = sqlite3changeset_concat(nLeft, aLeft, nRight, aRight, &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;
}

/*
** sqlite3session_foreach VARNAME CHANGESET SCRIPT
*/
static int test_sqlite3session_foreach(
  void * clientData,

static int test_sqlite3changeset_concat(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;                         /* Return code from changeset_invert() */


  TestStreamInput sLeft;          /* Input stream */
  TestStreamInput sRight;         /* Input stream */
  TestSessionsBlob sOut = {0,0};  /* Output blob */



  if( objc!=3 ){
    Tcl_WrongNumArgs(interp, 1, objv, "LEFT RIGHT");
    return TCL_ERROR;
  }

  memset(&sLeft, 0, sizeof(sLeft));
  memset(&sRight, 0, sizeof(sRight));
  sLeft.aData = Tcl_GetByteArrayFromObj(objv[1], &sLeft.nData);
  sRight.aData = Tcl_GetByteArrayFromObj(objv[2], &sRight.nData);
  sLeft.nStream = test_tcl_integer(interp, SESSION_STREAM_TCL_VAR);
  sRight.nStream = sLeft.nStream;

  if( sLeft.nStream>0 ){
    rc = sqlite3changeset_concat_str(
        testStreamInput, (void*)&sLeft,
        testStreamInput, (void*)&sRight,
        testSessionsOutput, (void*)&sOut
    );
  }else{
    rc = sqlite3changeset_concat(
        sLeft.nData, sLeft.aData, sRight.nData, sRight.aData, &sOut.n, &sOut.p
    );
  }

  if( rc!=SQLITE_OK ){
    rc = test_session_error(interp, rc);
  }else{
    Tcl_SetObjResult(interp,Tcl_NewByteArrayObj((unsigned char*)sOut.p,sOut.n));
  }

  sqlite3_free(sOut.p);
  return rc;
}

/*
** sqlite3session_foreach VARNAME CHANGESET SCRIPT
*/
static int test_sqlite3session_foreach(
  void * clientData,