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

set testprefix session5

proc do_concat_test {tn sql1 sql2} {
  sqlite3session S1 db main ; S1 attach *
  sqlite3session S2 db main ; S2 attach *

  execsql $sql1
  set C1 [S1 changeset]
  S1 delete

  sqlite3session S1 db main ; S1 attach *

  execsql $sql2
  set C2 [S1 changeset]
  S1 delete

  set C3 [S2 changeset]
  S2 delete

  set C4 [sqlite3changeset_concat $C1 $C2]

  set c3 [list]
  set c4 [list]
  sqlite3session_foreach c $C3 { lappend c3 $c }
  sqlite3session_foreach c $C4 { lappend c4 $c }
  set c3 [lsort $c3]
  set c4 [lsort $c4]

  do_test $tn [list set {} $c4] $c3













}

do_execsql_test 1.0 {
  CREATE TABLE t1(a PRIMARY KEY, b);
}

do_concat_test 1.1.1 {
................................................................................
  UPDATE t1 SET b = 'seven' WHERE a = 'I';
}
do_concat_test 1.2.7 {
  UPDATE t1 SET b = 'eight' WHERE a = 'I';
} {
  DELETE FROM t1 WHERE a = 'I';
}




















































finish_test

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

set testprefix session5

# Organization of tests:
#
#   session5-1.*: Simple tests to check the concat() function produces 
#                 correct results.
#
#   session5-2.*: More complicated tests.
#   
#   session5-3.*: Schema mismatch errors.
#

proc changeset_to_list {c} {
  set list [list]
  sqlite3session_foreach elem $c { lappend list $elem }
  lsort $list
}

proc do_concat_test {tn args} {

  set subtest 0
  foreach sql $args {
    incr subtest
    sqlite3session S db main ; S attach *
    execsql $sql

    set c [S changeset]
    if {[info commands s_prev] != ""} {
      set c_concat [sqlite3changeset_concat $c_prev $c]
      set c_two [s_prev changeset]
      s_prev delete

      set h_concat [changeset_to_list $c_concat]
      set h_two [changeset_to_list $c_two]

      do_test $tn.$subtest [list set {} $h_concat] $h_two
    }
    set c_prev $c
    rename S s_prev
  }

  catch { s_prev delete }
}

do_execsql_test 1.0 {
  CREATE TABLE t1(a PRIMARY KEY, b);
}

do_concat_test 1.1.1 {
................................................................................
  UPDATE t1 SET b = 'seven' WHERE a = 'I';
}
do_concat_test 1.2.7 {
  UPDATE t1 SET b = 'eight' WHERE a = 'I';
} {
  DELETE FROM t1 WHERE a = 'I';
}

db function indirect indirect 
proc indirect {{x -1}} {
  S indirect $x
  s_prev indirect $x
}

do_concat_test 2.1 {
  CREATE TABLE abc(a, b, c PRIMARY KEY);
  INSERT INTO abc VALUES(NULL, NULL, 1);
  INSERT INTO abc VALUES('abcdefghijkl', NULL, 2);
} {
  DELETE FROM abc WHERE c = 1;
  UPDATE abc SET c = 1 WHERE c = 2;
} {
  INSERT INTO abc VALUES('abcdefghijkl', NULL, 2);
  INSERT INTO abc VALUES(1.0, 2.0, 3);
} {
  UPDATE abc SET a = a-1;
} {
  CREATE TABLE def(d, e, f, PRIMARY KEY(e, f));
  INSERT INTO def VALUES('x', randomblob(11000), 67);
  INSERT INTO def SELECT d, e, f+1 FROM def;
  INSERT INTO def SELECT d, e, f+2 FROM def;
  INSERT INTO def SELECT d, e, f+4 FROM def;
} {
  DELETE FROM def WHERE rowid>4;
} { 
  INSERT INTO def SELECT d, e, f+4 FROM def; 
} {
  INSERT INTO abc VALUES(22, 44, -1);
} { 
  UPDATE abc SET c=-2 WHERE c=-1;
  UPDATE abc SET c=-3 WHERE c=-2;
} {
  UPDATE abc SET c=-4 WHERE c=-3;
} {
  UPDATE abc SET a=a+1 WHERE c=-3;
  UPDATE abc SET a=a+1 WHERE c=-3;
} {
  UPDATE abc SET a=a+1 WHERE c=-3;
  UPDATE abc SET a=a+1 WHERE c=-3;
} {
  INSERT INTO abc VALUES('one', 'two', 'three');
} {
  SELECT indirect(1);
  UPDATE abc SET a='one point five' WHERE c = 'three';
} {
  SELECT indirect(0);
  UPDATE abc SET a='one point six' WHERE c = 'three';
}

finish_test

      }
    }
  }

  *piHash = (h % pTab->nChange);
  return SQLITE_OK;
}















/*
** Based on the primary key values stored in change aRecord, calculate a
** hash key, assuming the has table has nBucket buckets. The hash keys
** calculated by this function are compatible with those calculated by
** sessionPreupdateHash().
*/
................................................................................
  int nBucket                     /* Assume this many buckets in hash table */
){
  unsigned int h = 0;             /* Value to return */
  int i;                          /* Used to iterate through columns */
  u8 *a = aRecord;                /* Used to iterate through change record */

  for(i=0; i<pTab->nCol; i++){
    int eType = *a++;
    int isPK = pTab->abPK[i];

    /* It is not possible for eType to be SQLITE_NULL here. The session 
    ** module does not record changes for rows with NULL values stored in
    ** primary key columns. */
    assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT 
         || eType==SQLITE_TEXT || eType==SQLITE_BLOB 

    );




    if( isPK ) h = HASH_APPEND(h, eType);
    if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
      if( isPK ) h = sessionHashAppendI64(h, sessionGetI64(a));
      a += 8;
    }else{
      int n; 
      a += sessionVarintGet(a, &n);
      if( isPK ) h = sessionHashAppendBlob(h, n, a);
      a += n;



    }
  }
  return (h % nBucket);
}

static int sessionSerialLen(u8 *a){
  int e = *a;
  int n;
  if( e==0 ) return 1;
  if( e==SQLITE_NULL ) return 1;
  if( e==SQLITE_INTEGER || e==SQLITE_FLOAT ) return 9;
  return sessionVarintGet(&a[1], &n) + 1 + n;
}

static int sessionChangeEqual(
  SessionTable *pTab,
  u8 *aLeft,                      /* Change record */
  u8 *aRight                      /* Change record */
){
  u8 *a1 = aLeft;
  u8 *a2 = aRight;
................................................................................
    int n1 = sessionSerialLen(a1);
    int n2 = sessionSerialLen(a2);

    if( pTab->abPK[i] && (n1!=n2 || memcmp(a1, a2, n1)) ){
      return 0;
    }
    a1 += n1;
    a2 += n1;
  }

  return 1;
}

static void sessionMergeRecord(
  u8 **paOut, 

      }
    }
  }

  *piHash = (h % pTab->nChange);
  return SQLITE_OK;
}

/*
** The buffer that the argument points to contains a serialized SQL value.
** Return the number of bytes of space occupied by the value (including
** the type byte).
*/
static int sessionSerialLen(u8 *a){
  int e = *a;
  int n;
  if( e==0 ) return 1;
  if( e==SQLITE_NULL ) return 1;
  if( e==SQLITE_INTEGER || e==SQLITE_FLOAT ) return 9;
  return sessionVarintGet(&a[1], &n) + 1 + n;
}

/*
** Based on the primary key values stored in change aRecord, calculate a
** hash key, assuming the has table has nBucket buckets. The hash keys
** calculated by this function are compatible with those calculated by
** sessionPreupdateHash().
*/
................................................................................
  int nBucket                     /* Assume this many buckets in hash table */
){
  unsigned int h = 0;             /* Value to return */
  int i;                          /* Used to iterate through columns */
  u8 *a = aRecord;                /* Used to iterate through change record */

  for(i=0; i<pTab->nCol; i++){
    int eType = *a;
    int isPK = pTab->abPK[i];

    /* It is not possible for eType to be SQLITE_NULL here. The session 
    ** module does not record changes for rows with NULL values stored in
    ** primary key columns. */
    assert( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT 
         || eType==SQLITE_TEXT || eType==SQLITE_BLOB 
         || eType==SQLITE_NULL || eType==0 
    );
    assert( !isPK || (eType!=0 && eType!=SQLITE_NULL) );

    if( isPK ){
      a++;
      h = HASH_APPEND(h, eType);
      if( eType==SQLITE_INTEGER || eType==SQLITE_FLOAT ){
        if( isPK ) h = sessionHashAppendI64(h, sessionGetI64(a));
        a += 8;
      }else{
        int n; 
        a += sessionVarintGet(a, &n);
        if( isPK ) h = sessionHashAppendBlob(h, n, a);
        a += n;
      }
    }else{
      a += sessionSerialLen(a);
    }
  }
  return (h % nBucket);
}










static int sessionChangeEqual(
  SessionTable *pTab,
  u8 *aLeft,                      /* Change record */
  u8 *aRight                      /* Change record */
){
  u8 *a1 = aLeft;
  u8 *a2 = aRight;
................................................................................
    int n1 = sessionSerialLen(a1);
    int n2 = sessionSerialLen(a2);

    if( pTab->abPK[i] && (n1!=n2 || memcmp(a1, a2, n1)) ){
      return 0;
    }
    a1 += n1;
    a2 += n2;
  }

  return 1;
}

static void sessionMergeRecord(
  u8 **paOut, 

** changeset. If it is not, the results are undefined.
*/
int sqlite3changeset_invert(
  int nIn, void *pIn,             /* Input changeset */
  int *pnOut, void **ppOut        /* OUT: Inverse of input */
);




int sqlite3changeset_concat(
  int nLeft, void *pLeft,         /* Input changeset */
  int nRight, void *Right,        /* Input changeset */
  int *pnOut, void **ppOut        /* OUT: Inverse of input */
);

/*
** 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. If it is not, the results are undefined.
*/
int sqlite3changeset_invert(
  int nIn, void *pIn,             /* Input changeset */
  int *pnOut, void **ppOut        /* OUT: Inverse of input */
);

/*
** CAPI3REF: Combine Two Changeset Objects
*/
int sqlite3changeset_concat(
  int nLeft, void *pLeft,         /* First input changeset */
  int nRight, void *Right,        /* Second input changeset */
  int *pnOut, void **ppOut        /* OUT: 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