}

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

if {![info exists testdir]} {
  set testdir [file join [file dirname [info script]] .. .. test]
} 
source [file join [file dirname [info script]] session_common.tcl]
source $testdir/tester.tcl
ifcapable !session {finish_test; return}
set testprefix sessionfault2

if 1 {

do_execsql_test 1.0.0 {
  CREATE TABLE t1(a PRIMARY KEY, b UNIQUE);
  INSERT INTO t1 VALUES(1, 1);
  INSERT INTO t1 VALUES(2, 2);
  INSERT INTO t1 VALUES(3, 3);

  faultsim_restore_and_reopen
} -body {
  sqlite3changeset_apply db $::C xConflict
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
  faultsim_integrity_check
}

#-------------------------------------------------------------------------
# OOM when collecting and apply a changeset that uses sqlite_stat1.
#
reset_db
forcedelete test.db2
sqlite3 db2 test.db2
do_common_sql {
  CREATE TABLE t1(a PRIMARY KEY, b UNIQUE, c);
  CREATE INDEX i1 ON t1(c);
  INSERT INTO t1 VALUES(1, 2, 3);
  INSERT INTO t1 VALUES(4, 5, 6);
  INSERT INTO t1 VALUES(7, 8, 9);
  CREATE TABLE t2(a, b, c);
  INSERT INTO t2 VALUES(1, 2, 3);
  INSERT INTO t2 VALUES(4, 5, 6);
  INSERT INTO t2 VALUES(7, 8, 9);
  ANALYZE;
}
faultsim_save_and_close
db2 close

do_faultsim_test 1.1 -faults oom-* -prep {
  catch {db2 close}
  catch {db close}
  faultsim_restore_and_reopen
  sqlite3 db2 test.db2
} -body {
  do_then_apply_sql {
    INSERT INTO sqlite_stat1 VALUES('x', 'y', 45);
    UPDATE sqlite_stat1 SET stat = 123 WHERE tbl='t1' AND idx='i1';
    UPDATE sqlite_stat1 SET stat = 456 WHERE tbl='t2';
  }
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
  faultsim_integrity_check
  if {$testrc==0} { compare_db db db2 }
}

#-------------------------------------------------------------------------
# OOM when collecting and using a rebase changeset.
#
reset_db
do_execsql_test 2.0 {
  CREATE TABLE t3(a, b, c, PRIMARY KEY(b, c));
  CREATE TABLE t4(x PRIMARY KEY, y, z);

  INSERT INTO t3 VALUES(1, 2, 3);
  INSERT INTO t3 VALUES(4, 2, 5);
  INSERT INTO t3 VALUES(7, 2, 9);

  INSERT INTO t4 VALUES('a', 'b', 'c');
  INSERT INTO t4 VALUES('d', 'e', 'f');
  INSERT INTO t4 VALUES('g', 'h', 'i');
}
faultsim_save_and_close

proc xConflict {ret args} { return $ret }

do_test 2.1 {
  faultsim_restore_and_reopen
  set C1 [changeset_from_sql {
    INSERT INTO t3 VALUES(10, 11, 12);
    UPDATE t4 SET y='j' WHERE x='g';
    DELETE FROM t4 WHERE x='a';
  }]

  faultsim_restore_and_reopen
  set C2 [changeset_from_sql {
    INSERT INTO t3 VALUES(1000, 11, 12);
    DELETE FROM t4 WHERE x='g';
  }]

  faultsim_restore_and_reopen
  sqlite3changeset_apply db $C1 [list xConflict OMIT]
  faultsim_save_and_close
} {}

do_faultsim_test 2.2 -faults oom* -prep {
  catch {db2 close}
  catch {db close}
  faultsim_restore_and_reopen
  sqlite3 db2 test.db2
} -body {
  set rebase [sqlite3changeset_apply_v2 db $::C2 [list xConflict OMIT]]
  set {} {}
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}
do_faultsim_test 2.3 -faults oom* -prep {
  catch {db2 close}
  catch {db close}
  faultsim_restore_and_reopen
  sqlite3 db2 test.db2
} -body {
  set rebase [sqlite3changeset_apply_v2 db $::C2 [list xConflict REPLACE]]
  set {} {}
} -test {
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}
do_faultsim_test 2.4 -faults oom* -prep {
  catch {db2 close}
  catch {db close}
  faultsim_restore_and_reopen
  set ::rebase [sqlite3changeset_apply_v2 db $::C2 [list xConflict REPLACE]]
} -body {
  sqlite3rebaser_create R
  R configure $::rebase
  R rebase $::C1
  set {} {}
} -test {
  catch { R delete } 
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}
do_faultsim_test 2.5 -faults oom* -prep {
  catch {db2 close}
  catch {db close}
  faultsim_restore_and_reopen
  set ::rebase [sqlite3changeset_apply_v2 db $::C2 [list xConflict OMIT]]
} -body {
  sqlite3rebaser_create R
  R configure $::rebase
  R rebase $::C1
  set {} {}
} -test {
  catch { R delete } 
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}

}

reset_db
do_execsql_test 3.0 {
  CREATE TABLE t1(x PRIMARY KEY, y, z);
  INSERT INTO t1 VALUES(3, 1, 4);
  INSERT INTO t1 VALUES(1, 5, 9);
}
faultsim_save_and_close

proc xConflict {ret args} { return $ret }

do_test 3.1 {
  faultsim_restore_and_reopen

  execsql { BEGIN; UPDATE t1 SET z=11; }
  set C1 [changeset_from_sql {
    UPDATE t1 SET z=10 WHERE x=1;
  }]
  execsql { ROLLBACK }

  execsql { BEGIN; UPDATE t1 SET z=11; }
  set C2 [changeset_from_sql {
    UPDATE t1 SET z=55 WHERE x=1;
  }]
  execsql { ROLLBACK }

  set ::rebase1 [sqlite3changeset_apply_v2 db $::C1 [list xConflict OMIT]]
  set ::rebase2 [sqlite3changeset_apply_v2 db $::C2 [list xConflict OMIT]]
  set {} {}
  execsql { SELECT * FROM t1 }
} {3 1 4 1 5 9}


do_faultsim_test 3.2 -faults oom* -prep {
  faultsim_restore_and_reopen
} -body {
  sqlite3rebaser_create R
  R configure $::rebase1
  R configure $::rebase2
  set {} {}
} -test {
  catch { R delete } 
  faultsim_test_result {0 {}} {1 SQLITE_NOMEM}
}


finish_test

# 2018 March 14
#
# 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.
#

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

set testprefix sessionrebase

set ::lConflict [list]
proc xConflict {args} {
  set res [lindex $::lConflict 0]
  set ::lConflict [lrange $::lConflict 1 end]
  return $res
}

#-------------------------------------------------------------------------
# The following test cases - 1.* - test that the rebase blobs output by
# sqlite3_changeset_apply_v2 look correct in some simple cases. The blob
# is itself a changeset, containing records determined as follows:
#
#   * For each conflict resolved with REPLACE, the rebase blob contains
#     a DELETE record. All fields other than the PK fields are undefined.
#
#   * For each conflict resolved with OMIT, the rebase blob contains an
#     INSERT record. For an INSERT or UPDATE operation, the indirect flag
#     is clear and all updated fields are defined. For a DELETE operation,
#     the indirect flag is set and all non-PK fields left undefined.
#
proc do_apply_v2_test {tn sql modsql conflict_handler res} {
  
  execsql BEGIN
  sqlite3session S db main
  S attach *
  execsql $sql
  set changeset [S changeset]
  S delete
  execsql ROLLBACK

  execsql BEGIN
  execsql $modsql
  set ::lConflict $conflict_handler
  set blob [sqlite3changeset_apply_v2 db $changeset xConflict]
  execsql ROLLBACK

  uplevel [list do_test $tn [list changeset_to_list $blob] [list {*}$res]]
}


set ::lConflict [list]
proc xConflict {args} {
  set res [lindex $::lConflict 0]
  set ::lConflict [lrange $::lConflict 1 end]
  return $res
}

# Take a copy of database test.db in file test.db2. Execute $sql1
# against test.db and $sql2 against test.db2. Capture a changeset
# for each. Then send the test.db2 changeset to test.db and apply
# it with the conflict handlers in $conflict_handler. Patch the
# test.db changeset and then execute it against test.db2. Test that
# the two databases come out the same.
#
proc do_rebase_test {tn sql1 sql2 conflict_handler {testsql ""} {testres ""}} {

  for {set i 1} {$i <= 2} {incr i} {
    forcedelete test.db2 test.db2-journal test.db2-wal
    forcecopy test.db test.db2
    sqlite3 db2 test.db2

    db eval BEGIN

    sqlite3session S1 db main
    S1 attach *
    execsql $sql1 db
    set c1 [S1 changeset]
    S1 delete

    if {$i==1} {
      sqlite3session S2 db2 main
      S2 attach *
      execsql $sql2 db2
      set c2 [S2 changeset]
      S2 delete
    } else {
      set c2 [list]
      foreach sql [split $sql2 ";"] {
        if {[string is space $sql]} continue
        sqlite3session S2 db2 main
        S2 attach *
        execsql $sql db2
        lappend c2 [S2 changeset]
        S2 delete
      }
    }

    set ::lConflict $conflict_handler
    set rebase [list]
    if {$i==1} {
      lappend rebase [sqlite3changeset_apply_v2 db $c2 xConflict]
    } else {
      foreach c $c2 {
#puts "apply_v2: [changeset_to_list $c]"
        lappend rebase [sqlite3changeset_apply_v2 db $c xConflict]
      }
      #puts "llength: [llength $rebase]"
    }
    #if {$tn=="2.1.4"} { puts [changeset_to_list $rebase] ; breakpoint }
    #puts [changeset_to_list [lindex $rebase 0]] ; breakpoint
    #puts [llength $rebase]
  
    sqlite3rebaser_create R
    foreach r $rebase {
#puts [changeset_to_list $r]
      R configure $r
    }
    set c1r [R rebase $c1]
    R delete
    #if {$tn=="2.1.4"} { puts [changeset_to_list $c1r] }
  
    sqlite3changeset_apply_v2 db2 $c1r xConflictAbort
  
    if {[string range $tn end end]!="*"} {
      uplevel [list do_test $tn.$i.1 [list compare_db db db2] {}]
    }
    db2 close
  
    if {$testsql!=""} {
      uplevel [list do_execsql_test $tn.$i.2 $testsql $testres]
    }
  
    db eval ROLLBACK
  }
}

do_execsql_test 1.0 {
  CREATE TABLE t1(a INTEGER PRIMARY KEY, b);
  INSERT INTO t1 VALUES(1, 'value A');
}

do_apply_v2_test 1.1.1 {
  UPDATE t1 SET b = 'value B' WHERE a=1;
} {
  UPDATE t1 SET b = 'value C' WHERE a=1;
} {
  OMIT
} {
  {INSERT t1 0 X. {} {i 1 t {value B}}}
}

do_apply_v2_test 1.1.2 {
  UPDATE t1 SET b = 'value B' WHERE a=1;
} {
  UPDATE t1 SET b = 'value C' WHERE a=1;
} {
  REPLACE
} {
  {INSERT t1 1 X. {} {i 1 t {value B}}}
}

do_apply_v2_test 1.2.1 {
  INSERT INTO t1 VALUES(2, 'first');
} {
  INSERT INTO t1 VALUES(2, 'second');
} {
  OMIT
} {
  {INSERT t1 0 X. {} {i 2 t first}}
}
do_apply_v2_test 1.2.2 {
  INSERT INTO t1 VALUES(2, 'first');
} {
  INSERT INTO t1 VALUES(2, 'second');
} {
  REPLACE
} {
  {INSERT t1 1 X. {} {i 2 t first}}
}

do_apply_v2_test 1.3.1 {
  DELETE FROM t1 WHERE a=1;
} {
  UPDATE t1 SET b='value D' WHERE a=1;
} {
  OMIT
} {
  {DELETE t1 0 X. {i 1 t {value A}} {}}
}
do_apply_v2_test 1.3.2 {
  DELETE FROM t1 WHERE a=1;
} {
  UPDATE t1 SET b='value D' WHERE a=1;
} {
  REPLACE
} {
  {DELETE t1 1 X. {i 1 t {value A}} {}}
}

#-------------------------------------------------------------------------
# Test cases 2.* - simple tests of rebasing actual changesets.
#
#    2.1.1 - 1u2u1r
#    2.1.2 - 1u2u2r
#    2.1.3 - 1d2d
#    2.1.4 - 1d2u1r
#    2.1.5 - 1d2u2r !!
#    2.1.6 - 1u2d1r
#    2.1.7 - 1u2d2r
#
#    2.1.8 - 1i2i2r
#    2.1.9 - 1i2i1r
#

proc xConflictAbort {args} {
  return "ABORT"
}

reset_db
do_execsql_test 2.1.0 {
  CREATE TABLE t1 (a INTEGER PRIMARY KEY, b TEXT);
  INSERT INTO t1 VALUES(1, 'one');
  INSERT INTO t1 VALUES(2, 'two');
  INSERT INTO t1 VALUES(3, 'three');
}
do_rebase_test 2.1.1 {
  UPDATE t1 SET b = 'two.1' WHERE a=2
} {
  UPDATE t1 SET b = 'two.2' WHERE a=2;
} {
  OMIT
} { SELECT * FROM t1 } {1 one 2 two.1 3 three}

do_rebase_test 2.1.2 {
  UPDATE t1 SET b = 'two.1' WHERE a=2
} {
  UPDATE t1 SET b = 'two.2' WHERE a=2;
} {
  REPLACE
} { SELECT * FROM t1 } {1 one 2 two.2 3 three}

do_rebase_test 2.1.3 {
  DELETE FROM t1 WHERE a=3
} {
  DELETE FROM t1 WHERE a=3;
} {
  OMIT
} { SELECT * FROM t1 } {1 one 2 two}

do_rebase_test 2.1.4 {
  DELETE FROM t1 WHERE a=1
} {
  UPDATE t1 SET b='one.2' WHERE a=1
} {
  OMIT
} { SELECT * FROM t1 } {2 two 3 three}

#do_rebase_test 2.1.5 {
#  DELETE FROM t1 WHERE a=1;
#} {
#  UPDATE t1 SET b='one.2' WHERE a=1
#} {
#  REPLACE
#} { SELECT * FROM t1 } {2 two 3 three}

do_rebase_test 2.1.6 {
  UPDATE t1 SET b='three.1' WHERE a=3
} {
  DELETE FROM t1 WHERE a=3;
} {
  OMIT
} { SELECT * FROM t1 } {1 one 2 two 3 three.1}

do_rebase_test 2.1.7 {
  UPDATE t1 SET b='three.1' WHERE a=3
} {
  DELETE FROM t1 WHERE a=3;
} {
  REPLACE
} { SELECT * FROM t1 } {1 one 2 two}

do_rebase_test 2.1.8 {
  INSERT INTO t1 VALUES(4, 'four.1')
} {
  INSERT INTO t1 VALUES(4, 'four.2');
} {
  REPLACE
} { SELECT * FROM t1 } {1 one 2 two 3 three 4 four.2}

do_rebase_test 2.1.9 {
  INSERT INTO t1 VALUES(4, 'four.1')
} {
  INSERT INTO t1 VALUES(4, 'four.2');
} {
  OMIT
} { SELECT * FROM t1 } {1 one 2 two 3 three 4 four.1}

do_execsql_test 2.2.0 {
  CREATE TABLE t2(x, y, z PRIMARY KEY);
  INSERT INTO t2 VALUES('i', 'a', 'A');
  INSERT INTO t2 VALUES('ii', 'b', 'B');
  INSERT INTO t2 VALUES('iii', 'c', 'C');

  CREATE TABLE t3(a INTEGER PRIMARY KEY, b, c);
  INSERT INTO t3 VALUES(-1, 'z', 'Z');
  INSERT INTO t3 VALUES(-2, 'y', 'Y');
}

do_rebase_test 2.2.1 {
  UPDATE t2 SET x=1 WHERE z='A'
} {
  UPDATE t2 SET y='one' WHERE z='A';
} {
} { SELECT * FROM t2 WHERE z='A' } { 1 one A }

do_rebase_test 2.2.2 {
  UPDATE t2 SET x=1, y='one' WHERE z='B'
} {
  UPDATE t2 SET y='two' WHERE z='B';
} {
  REPLACE
} { SELECT * FROM t2 WHERE z='B' } { 1 two B }

do_rebase_test 2.2.3 {
  UPDATE t2 SET x=1, y='one' WHERE z='B'
} {
  UPDATE t2 SET y='two' WHERE z='B';
} {
  OMIT
} { SELECT * FROM t2 WHERE z='B' } { 1 one B }

#-------------------------------------------------------------------------
reset_db
do_execsql_test 3.0 {
  CREATE TABLE t3(a, b, c, PRIMARY KEY(b, c));
  CREATE TABLE abcdefghijkl(x PRIMARY KEY, y, z);

  INSERT INTO t3 VALUES(1, 2, 3);
  INSERT INTO t3 VALUES(4, 2, 5);
  INSERT INTO t3 VALUES(7, 2, 9);

  INSERT INTO abcdefghijkl VALUES('a', 'b', 'c');
  INSERT INTO abcdefghijkl VALUES('d', 'e', 'f');
  INSERT INTO abcdefghijkl VALUES('g', 'h', 'i');
}

breakpoint
#  do_rebase_test 3.6.tn {
#    UPDATE abcdefghijkl SET z='X', y='X' WHERE x='d';
#  } {
#    UPDATE abcdefghijkl SET y=1 WHERE x='d';
#    UPDATE abcdefghijkl SET z=1 WHERE x='d';
#  } [list REPLACE REPLACE REPLACE]

foreach {tn p} {
    1 OMIT 2 REPLACE
} {
  do_rebase_test 3.1.$tn {
    INSERT INTO t3 VALUES(1, 1, 1);
    UPDATE abcdefghijkl SET y=2;
  } {
    INSERT INTO t3 VALUES(4, 1, 1);
    DELETE FROM abcdefghijkl;
  } [list $p $p $p $p $p $p $p $p]

  do_rebase_test 3.2.$tn {
    INSERT INTO abcdefghijkl SELECT * FROM t3;
    UPDATE t3 SET b=b+1;
  } {
    INSERT INTO t3 VALUES(3, 3, 3);
    INSERT INTO abcdefghijkl SELECT * FROM t3;
  } [list $p $p $p $p $p $p $p $p]

  do_rebase_test 3.3.$tn {
    INSERT INTO abcdefghijkl VALUES(22, 23, 24);
  } {
    INSERT INTO abcdefghijkl VALUES(22, 25, 26);
    UPDATE abcdefghijkl SET y=400 WHERE x=22;
  } [list $p $p $p $p $p $p $p $p]

  do_rebase_test 3.4.$tn {
    INSERT INTO abcdefghijkl VALUES(22, 23, 24);
  } {
    INSERT INTO abcdefghijkl VALUES(22, 25, 26);
    UPDATE abcdefghijkl SET y=400 WHERE x=22;
  } [list REPLACE $p]

  do_rebase_test 3.5.$tn* {
    UPDATE abcdefghijkl SET y='X' WHERE x='d';
  } {
    DELETE FROM abcdefghijkl WHERE x='d';
    INSERT INTO abcdefghijkl VALUES('d', NULL, NULL);
  } [list $p $p $p]
  do_rebase_test 3.5.$tn {
    UPDATE abcdefghijkl SET y='X' WHERE x='d';
  } {
    DELETE FROM abcdefghijkl WHERE x='d';
    INSERT INTO abcdefghijkl VALUES('d', NULL, NULL);
  } [list REPLACE $p $p]

  do_rebase_test 3.6.$tn {
    UPDATE abcdefghijkl SET z='X', y='X' WHERE x='d';
  } {
    UPDATE abcdefghijkl SET y=1 WHERE x='d';
    UPDATE abcdefghijkl SET z=1 WHERE x='d';
  } [list REPLACE $p $p]
}

#-------------------------------------------------------------------------
# Check that apply_v2() does not create a rebase buffer for a patchset.
# And that it is not possible to rebase a patchset.
#
do_execsql_test 4.0 {
  CREATE TABLE t5(o PRIMARY KEY, p, q);
  INSERT INTO t5 VALUES(1, 2, 3);
  INSERT INTO t5 VALUES(4, 5, 6);
}
foreach {tn cmd rebasable} {
  1 patchset 0
  2 changeset 1
} {
  proc xConflict {args} { return "OMIT" }
  do_test 4.1.$tn {
    execsql {
      BEGIN;
      DELETE FROM t5 WHERE o=4;
    }

    sqlite3session S db main
    S attach *
    execsql {
      INSERT INTO t5 VALUES(4, 'five', 'six');
    }
    set P [S $cmd]
    S delete

    execsql ROLLBACK;

    set ::rebase [sqlite3changeset_apply_v2 db $P xConflict]
    expr [llength $::rebase]>0
  } $rebasable
}

foreach {tn cmd rebasable} {
  1 patchset 0
  2 changeset 1
} {
  do_test 4.2.$tn {
    sqlite3session S db main
    S attach *
    execsql {
      INSERT INTO t5 VALUES(5+$tn, 'five', 'six');
    }
    set P [S $cmd]
    S delete

    sqlite3rebaser_create R
    R configure $::rebase
    expr [catch {R rebase $P}]==0
  } $rebasable

  catch { R delete }
}
finish_test

**
** As in the changeset format, each field of the single record that is part
** of a patchset change is associated with the correspondingly positioned
** table column, counting from left to right within the CREATE TABLE 
** statement.
**
** For a DELETE change, all fields within the record except those associated
** with PRIMARY KEY columns are omitted. The PRIMARY KEY fields contain the
** values identifying the row to delete.
**
** For an UPDATE change, all fields except those associated with PRIMARY KEY
** columns and columns that are modified by the UPDATE are set to "undefined".
** PRIMARY KEY fields contain the values identifying the table row to update,
** and fields associated with modified columns contain the new column values.
**
** The records associated with INSERT changes are in the same format as for

** 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 || e==0xFF ) 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

  int iCol;                       /* Used to iterate through table columns */

  for(iCol=0; iCol<pTab->nCol; iCol++){
    if( pTab->abPK[iCol] ){
      int n1 = sessionSerialLen(a1);
      int n2 = sessionSerialLen(a2);

      if( n1!=n2 || memcmp(a1, a2, n1) ){
        return 0;
      }
      a1 += n1;
      a2 += n2;
    }else{
      if( bLeftPkOnly==0 ) a1 += sessionSerialLen(a1);
      if( bRightPkOnly==0 ) a2 += sessionSerialLen(a2);

  int nSql = -1;

  if( 0==sqlite3_stricmp("sqlite_stat1", zTab) ){
    zSql = sqlite3_mprintf(
        "SELECT tbl, ?2, stat FROM %Q.sqlite_stat1 WHERE tbl IS ?1 AND "
        "idx IS (CASE WHEN ?2=X'' THEN NULL ELSE ?2 END)", zDb
    );
    if( zSql==0 ) rc = SQLITE_NOMEM;
  }else{
    int i;
    const char *zSep = "";
    SessionBuffer buf = {0, 0, 0};

    sessionAppendStr(&buf, "SELECT * FROM ", &rc);
    sessionAppendIdent(&buf, zDb, &rc);

** successfully advanced to the next change in the changeset, an SQLite 
** error code if an error occurs, or SQLITE_DONE if there are no further 
** changes in the changeset.
*/
static int sessionChangesetNext(
  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 *pbNew                      /* If non-NULL, true if new table */
){
  int i;
  u8 op;

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

  /* If the iterator is in the error-state, return immediately. */

  }

  sessionDiscardData(&p->in);
  p->in.iCurrent = p->in.iNext;

  op = p->in.aData[p->in.iNext++];
  while( op=='T' || op=='P' ){
    if( pbNew ) *pbNew = 1;
    p->bPatchset = (op=='P');
    if( sessionChangesetReadTblhdr(p) ) return p->rc;
    if( (p->rc = sessionInputBuffer(&p->in, 2)) ) return p->rc;
    p->in.iCurrent = p->in.iNext;
    if( p->in.iNext>=p->in.nData ) return SQLITE_DONE;
    op = p->in.aData[p->in.iNext++];
  }

** change in the changeset. This function may return SQLITE_ROW, SQLITE_DONE
** or SQLITE_CORRUPT.
**
** This function may not be called on iterators passed to a conflict handler
** callback by changeset_apply().
*/
int sqlite3changeset_next(sqlite3_changeset_iter *p){
  return sessionChangesetNext(p, 0, 0, 0);
}

/*
** The following function extracts information on the current change
** from a changeset iterator. It may only be called after changeset_next()
** has returned SQLITE_ROW.
*/

  sqlite3_stmt *pSelect;          /* SELECT statement */
  int nCol;                       /* Size of azCol[] and abPK[] arrays */
  const char **azCol;             /* Array of column names */
  u8 *abPK;                       /* Boolean array - true if column is in PK */
  int bStat1;                     /* True if table is sqlite_stat1 */
  int bDeferConstraints;          /* True to defer constraints */
  SessionBuffer constraints;      /* Deferred constraints are stored here */
  SessionBuffer rebase;           /* Rebase information (if any) here */
  int bRebaseStarted;             /* If table header is already in rebase */
};

/*
** Formulate a statement to DELETE a row from database db. Assuming a table
** structure like this:
**
**     CREATE TABLE x(a, b, c, d, PRIMARY KEY(a, c));

  if( rc==SQLITE_OK ){
    rc = sessionPrepare(db, &p->pDelete,
        "DELETE FROM main.sqlite_stat1 WHERE tbl=?1 AND idx IS "
        "CASE WHEN length(?2)=0 AND typeof(?2)='blob' THEN NULL ELSE ?2 END "
        "AND (?4 OR stat IS ?3)"
    );
  }

  return rc;
}

/*
** A wrapper around sqlite3_bind_value() that detects an extra problem. 
** See comments in the body of this function for details.
*/

  if( rc==SQLITE_OK ){
    rc = sqlite3_step(pSelect);
    if( rc!=SQLITE_ROW ) rc = sqlite3_reset(pSelect);
  }

  return rc;
}

/*
** This function is called from within sqlite3changset_apply_v2() when
** a conflict is encountered and resolved using conflict resolution
** mode eType (either SQLITE_CHANGESET_OMIT or SQLITE_CHANGESET_REPLACE)..
** It adds a conflict resolution record to the buffer in 
** SessionApplyCtx.rebase, which will eventually be returned to the caller
** of apply_v2() as the "rebase" buffer.
**
** Return SQLITE_OK if successful, or an SQLite error code otherwise.
*/
static int sessionRebaseAdd(
  SessionApplyCtx *p,             /* Apply context */
  int eType,                      /* Conflict resolution (OMIT or REPLACE) */
  sqlite3_changeset_iter *pIter   /* Iterator pointing at current change */
){
  int rc = SQLITE_OK;
  int i;
  int eOp = pIter->op;
  if( p->bRebaseStarted==0 ){
    /* Append a table-header to the rebase buffer */
    const char *zTab = pIter->zTab;
    sessionAppendByte(&p->rebase, 'T', &rc);
    sessionAppendVarint(&p->rebase, p->nCol, &rc);
    sessionAppendBlob(&p->rebase, p->abPK, p->nCol, &rc);
    sessionAppendBlob(&p->rebase, (u8*)zTab, (int)strlen(zTab)+1, &rc);
    p->bRebaseStarted = 1;
  }

  assert( eType==SQLITE_CHANGESET_REPLACE||eType==SQLITE_CHANGESET_OMIT );
  assert( eOp==SQLITE_DELETE || eOp==SQLITE_INSERT || eOp==SQLITE_UPDATE );

  sessionAppendByte(&p->rebase, 
      (eOp==SQLITE_DELETE ? SQLITE_DELETE : SQLITE_INSERT), &rc
  );
  sessionAppendByte(&p->rebase, (eType==SQLITE_CHANGESET_REPLACE), &rc);
  for(i=0; i<p->nCol; i++){
    sqlite3_value *pVal = 0;
    if( eOp==SQLITE_DELETE || (eOp==SQLITE_UPDATE && p->abPK[i]) ){
      sqlite3changeset_old(pIter, i, &pVal);
    }else{
      sqlite3changeset_new(pIter, i, &pVal);
    }
    sessionAppendValue(&p->rebase, pVal, &rc);
  }

  return rc;
}

/*
** Invoke the conflict handler for the change that the changeset iterator
** currently points to.
**
** Argument eType must be either CHANGESET_DATA or CHANGESET_CONFLICT.
** If argument pbReplace is NULL, then the type of conflict handler invoked

  }else if( rc==SQLITE_OK ){
    if( p->bDeferConstraints && eType==SQLITE_CHANGESET_CONFLICT ){
      /* Instead of invoking the conflict handler, append the change blob
      ** to the SessionApplyCtx.constraints buffer. */
      u8 *aBlob = &pIter->in.aData[pIter->in.iCurrent];
      int nBlob = pIter->in.iNext - pIter->in.iCurrent;
      sessionAppendBlob(&p->constraints, aBlob, nBlob, &rc);
      return SQLITE_OK;
    }else{
      /* No other row with the new.* primary key. */
      res = xConflict(pCtx, eType+1, pIter);
      if( res==SQLITE_CHANGESET_REPLACE ) rc = SQLITE_MISUSE;
    }
  }

        rc = SQLITE_ABORT;
        break;

      default:
        rc = SQLITE_MISUSE;
        break;
    }
    if( rc==SQLITE_OK ){
      rc = sessionRebaseAdd(p, res, pIter);
    }
  }

  return rc;
}

/*
** Attempt to apply the change that the iterator passed as the first argument

  void *pCtx                      /* First argument passed to xConflict */
){
  int bReplace = 0;
  int bRetry = 0;
  int rc;

  rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, &bReplace, &bRetry);
  if( rc==SQLITE_OK ){

    /* If the bRetry flag is set, the change has not been applied due to an
    ** SQLITE_CHANGESET_DATA problem (i.e. this is an UPDATE or DELETE and
    ** a row with the correct PK is present in the db, but one or more other
    ** fields do not contain the expected values) and the conflict handler 
    ** returned SQLITE_CHANGESET_REPLACE. In this case retry the operation,
    ** but pass NULL as the final argument so that sessionApplyOneOp() ignores
    ** the SQLITE_CHANGESET_DATA problem.  */
    if( bRetry ){
      assert( pIter->op==SQLITE_UPDATE || pIter->op==SQLITE_DELETE );
      rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
    }

    /* If the bReplace flag is set, the change is an INSERT that has not
    ** been performed because the database already contains a row with the
    ** specified primary key and the conflict handler returned
    ** SQLITE_CHANGESET_REPLACE. In this case remove the conflicting row
    ** before reattempting the INSERT.  */
    else if( bReplace ){
      assert( pIter->op==SQLITE_INSERT );
      rc = sqlite3_exec(db, "SAVEPOINT replace_op", 0, 0, 0);
      if( rc==SQLITE_OK ){
        rc = sessionBindRow(pIter, 
            sqlite3changeset_new, pApply->nCol, pApply->abPK, pApply->pDelete);
        sqlite3_bind_int(pApply->pDelete, pApply->nCol+1, 1);
      }
      if( rc==SQLITE_OK ){
        sqlite3_step(pApply->pDelete);
        rc = sqlite3_reset(pApply->pDelete);
      }
      if( rc==SQLITE_OK ){
        rc = sessionApplyOneOp(pIter, pApply, xConflict, pCtx, 0, 0);
      }
      if( rc==SQLITE_OK ){
        rc = sqlite3_exec(db, "RELEASE replace_op", 0, 0, 0);
      }
    }
  }

  return rc;
}

/*

    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 */
  void **ppRebase, int *pnRebase  /* OUT: Rebase information */
){
  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 */
  int bPatchset;

      if( rc!=SQLITE_OK ) break;

      sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
      sqlite3_finalize(sApply.pDelete);
      sqlite3_finalize(sApply.pUpdate); 
      sqlite3_finalize(sApply.pInsert);
      sqlite3_finalize(sApply.pSelect);

      sApply.db = db;
      sApply.pDelete = 0;
      sApply.pUpdate = 0;
      sApply.pInsert = 0;
      sApply.pSelect = 0;
      sApply.nCol = 0;
      sApply.azCol = 0;
      sApply.abPK = 0;
      sApply.bStat1 = 0;
      sApply.bDeferConstraints = 1;
      sApply.bRebaseStarted = 0;
      memset(&sApply.constraints, 0, sizeof(SessionBuffer));

      /* If an xFilter() callback was specified, invoke it now. If the 
      ** xFilter callback returns zero, skip this table. If it returns
      ** non-zero, proceed. */
      schemaMismatch = (xFilter && (0==xFilter(pCtx, zNew)));
      if( schemaMismatch ){
        zTab = sqlite3_mprintf("%s", zNew);

  if( rc==SQLITE_OK ){
    rc = sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
  }else{
    sqlite3_exec(db, "ROLLBACK TO changeset_apply", 0, 0, 0);
    sqlite3_exec(db, "RELEASE changeset_apply", 0, 0, 0);
  }

  if( rc==SQLITE_OK && bPatchset==0 && ppRebase && pnRebase ){
    *ppRebase = (void*)sApply.rebase.aBuf;
    *pnRebase = sApply.rebase.nBuf;
    sApply.rebase.aBuf = 0;
  }
  sqlite3_finalize(sApply.pInsert);
  sqlite3_finalize(sApply.pDelete);
  sqlite3_finalize(sApply.pUpdate);
  sqlite3_finalize(sApply.pSelect);
  sqlite3_free((char*)sApply.azCol);  /* cast works around VC++ bug */
  sqlite3_free((char*)sApply.constraints.aBuf);
  sqlite3_free((char*)sApply.rebase.aBuf);
  sqlite3_mutex_leave(sqlite3_db_mutex(db));
  return rc;
}

/*
** Apply the changeset passed via pChangeset/nChangeset to the main 
** database attached to handle "db".
*/
int sqlite3changeset_apply_v2(
  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 */
  void **ppRebase, int *pnRebase
){
  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, ppRebase, pnRebase
    );
  }
  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(

  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 */
){

  return sqlite3changeset_apply_v2(

      db, nChangeset, pChangeset, xFilter, xConflict, pCtx, 0, 0


  );
}

/*
** 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_v2_strm(
  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 */
  void **ppRebase, int *pnRebase
){
  sqlite3_changeset_iter *pIter;  /* Iterator to skip through changeset */  
  int rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetApply(
        db, pIter, xFilter, xConflict, pCtx, ppRebase, pnRebase
    );
  }
  return rc;
}
int sqlite3changeset_apply_strm(
  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 */
){

  return sqlite3changeset_apply_v2_strm(

      db, xInput, pIn, xFilter, xConflict, pCtx, 0, 0


  );
}

/*
** sqlite3_changegroup handle.
*/
struct sqlite3_changegroup {
  int rc;                         /* Error code */
  int bPatch;                     /* True to accumulate patchsets */
  SessionTable *pList;            /* List of tables in current patch */
};

/*
** 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(
  SessionTable *pTab,             /* Table structure */
  int bRebase,                    /* True for a rebase hash-table */
  int bPatchset,                  /* True for patchsets */
  SessionChange *pExist,          /* Existing change */
  int op2,                        /* Second change operation */
  int bIndirect,                  /* True if second change is indirect */
  u8 *aRec,                       /* Second change record */
  int nRec,                       /* Number of bytes in aRec */
  SessionChange **ppNew           /* OUT: Merged change */
){
  SessionChange *pNew = 0;
  int rc = SQLITE_OK;

  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->aRecord = (u8*)&pNew[1];
    if( bIndirect==0 || bRebase==0 ){
      pNew->nRecord = nRec;
      memcpy(pNew->aRecord, aRec, nRec);
    }else{
      int i;
      u8 *pIn = aRec;
      u8 *pOut = pNew->aRecord;
      for(i=0; i<pTab->nCol; i++){
        int nIn = sessionSerialLen(pIn);
        if( *pIn==0 ){
          *pOut++ = 0;
        }else if( pTab->abPK[i]==0 ){
          *pOut++ = 0xFF;
        }else{
          memcpy(pOut, pIn, nIn);
          pOut += nIn;
        }
        pIn += nIn;
      }
      pNew->nRecord = pOut - pNew->aRecord;
    }
  }else if( bRebase ){
    if( pExist->op==SQLITE_DELETE && pExist->bIndirect ){
      *ppNew = pExist;
    }else{
      int nByte = nRec + pExist->nRecord + sizeof(SessionChange);
      pNew = (SessionChange*)sqlite3_malloc(nByte);
      if( pNew==0 ){
        rc = SQLITE_NOMEM;
      }else{
        int i;
        u8 *a1 = pExist->aRecord;
        u8 *a2 = aRec;
        u8 *pOut;

        memset(pNew, 0, nByte);
        pNew->bIndirect = bIndirect || pExist->bIndirect;
        pNew->op = op2;
        pOut = pNew->aRecord = (u8*)&pNew[1];

        for(i=0; i<pTab->nCol; i++){
          int n1 = sessionSerialLen(a1);
          int n2 = sessionSerialLen(a2);
          if( *a1==0xFF || (pTab->abPK[i]==0 && bIndirect) ){
            *pOut++ = 0xFF;
          }else if( *a2==0 ){
            memcpy(pOut, a1, n1);
            pOut += n1;
          }else{
            memcpy(pOut, a2, n2);
            pOut += n2;
          }
          a1 += n1;
          a2 += n2;
        }
        pNew->nRecord = pOut - pNew->aRecord;
      }
      sqlite3_free(pExist);
    }
  }else{
    int op1 = pExist->op;

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

        pNew->nRecord = (int)(aCsr - pNew->aRecord);
      }
      sqlite3_free(pExist);
    }
  }

  *ppNew = pNew;
  return rc;
}

/*
** Add all changes in the changeset traversed by the iterator passed as
** the first argument to the changegroup hash tables.
*/
static int sessionChangesetToHash(
  sqlite3_changeset_iter *pIter,   /* Iterator to read from */
  sqlite3_changegroup *pGrp,       /* Changegroup object to add changeset to */
  int bRebase                      /* True if hash table is for rebasing */
){
  u8 *aRec;
  int nRec;
  int rc = SQLITE_OK;
  SessionTable *pTab = 0;


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

        pExist = *pp;
        *pp = (*pp)->pNext;
        pTab->nEntry--;
        break;
      }
    }

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

*/
int sqlite3changegroup_add(sqlite3_changegroup *pGrp, int nData, void *pData){
  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
  int rc;                         /* Return code */

  rc = sqlite3changeset_start(&pIter, nData, pData);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetToHash(pIter, pGrp, 0);
  }
  sqlite3changeset_finalize(pIter);
  return rc;
}

/*
** Obtain a buffer containing a changeset representing the concatenation

  void *pIn
){
  sqlite3_changeset_iter *pIter;  /* Iterator opened on pData/nData */
  int rc;                         /* Return code */

  rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetToHash(pIter, pGrp, 0);
  }
  sqlite3changeset_finalize(pIter);
  return rc;
}

/*
** Streaming versions of changegroup_output().

  if( rc==SQLITE_OK ){
    rc = sqlite3changegroup_output_strm(pGrp, xOutput, pOut);
  }
  sqlite3changegroup_delete(pGrp);

  return rc;
}

/*
** Changeset rebaser handle.
*/
struct sqlite3_rebaser {
  sqlite3_changegroup grp;        /* Hash table */
};

/*
** Buffers a1 and a2 must both contain a sessions module record nCol
** fields in size. This function appends an nCol sessions module 
** record to buffer pBuf that is a copy of a1, except that for
** each field that is undefined in a1[], swap in the field from a2[].
*/
static void sessionAppendRecordMerge(
  SessionBuffer *pBuf,            /* Buffer to append to */
  int nCol,                       /* Number of columns in each record */
  u8 *a1, int n1,                 /* Record 1 */
  u8 *a2, int n2,                 /* Record 2 */
  int *pRc                        /* IN/OUT: error code */
){
  sessionBufferGrow(pBuf, n1+n2, pRc);
  if( *pRc==SQLITE_OK ){
    int i;
    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
    for(i=0; i<nCol; i++){
      int nn1 = sessionSerialLen(a1);
      int nn2 = sessionSerialLen(a2);
      if( *a1==0 || *a1==0xFF ){
        memcpy(pOut, a2, nn2);
        pOut += nn2;
      }else{
        memcpy(pOut, a1, nn1);
        pOut += nn1;
      }
      a1 += nn1;
      a2 += nn2;
    }

    pBuf->nBuf = pOut-pBuf->aBuf;
    assert( pBuf->nBuf<=pBuf->nAlloc );
  }
}

/*
** This function is called when rebasing a local UPDATE change against one 
** or more remote UPDATE changes. The aRec/nRec buffer contains the current
** old.* and new.* records for the change. The rebase buffer (a single
** record) is in aChange/nChange. The rebased change is appended to buffer
** pBuf.
**
** Rebasing the UPDATE involves: 
**
**   * Removing any changes to fields for which the corresponding field
**     in the rebase buffer is set to "replaced" (type 0xFF). If this
**     means the UPDATE change updates no fields, nothing is appended
**     to the output buffer.
**
**   * For each field modified by the local change for which the 
**     corresponding field in the rebase buffer is not "undefined" (0x00)
**     or "replaced" (0xFF), the old.* value is replaced by the value
**     in the rebase buffer.
*/
static void sessionAppendPartialUpdate(
  SessionBuffer *pBuf,            /* Append record here */
  sqlite3_changeset_iter *pIter,  /* Iterator pointed at local change */
  u8 *aRec, int nRec,             /* Local change */
  u8 *aChange, int nChange,       /* Record to rebase against */
  int *pRc                        /* IN/OUT: Return Code */
){
  sessionBufferGrow(pBuf, 2+nRec+nChange, pRc);
  if( *pRc==SQLITE_OK ){
    int bData = 0;
    u8 *pOut = &pBuf->aBuf[pBuf->nBuf];
    int i;
    u8 *a1 = aRec;
    u8 *a2 = aChange;

    *pOut++ = SQLITE_UPDATE;
    *pOut++ = pIter->bIndirect;
    for(i=0; i<pIter->nCol; i++){
      int n1 = sessionSerialLen(a1);
      int n2 = sessionSerialLen(a2);
      if( pIter->abPK[i] || a2[0]==0 ){
        if( !pIter->abPK[i] ) bData = 1;
        memcpy(pOut, a1, n1);
        pOut += n1;
      }else if( a2[0]!=0xFF ){
        bData = 1;
        memcpy(pOut, a2, n2);
        pOut += n2;
      }else{
        *pOut++ = '\0';
      }
      a1 += n1;
      a2 += n2;
    }
    if( bData ){
      a2 = aChange;
      for(i=0; i<pIter->nCol; i++){
        int n1 = sessionSerialLen(a1);
        int n2 = sessionSerialLen(a2);
        if( pIter->abPK[i] || a2[0]!=0xFF ){
          memcpy(pOut, a1, n1);
          pOut += n1;
        }else{
          *pOut++ = '\0';
        }
        a1 += n1;
        a2 += n2;
      }
      pBuf->nBuf = (pOut - pBuf->aBuf);
    }
  }
}

/*
** pIter is configured to iterate through a changeset. This function rebases 
** that changeset according to the current configuration of the rebaser 
** object passed as the first argument. If no error occurs and argument xOutput
** is not NULL, then the changeset is returned to the caller by invoking
** xOutput zero or more times and SQLITE_OK returned. Or, if xOutput is NULL,
** then (*ppOut) is set to point to a buffer containing the rebased changeset
** before this function returns. In this case (*pnOut) is set to the size of
** the buffer in bytes.  It is the responsibility of the caller to eventually
** free the (*ppOut) buffer using sqlite3_free(). 
**
** If an error occurs, an SQLite error code is returned. If ppOut and
** pnOut are not NULL, then the two output parameters are set to 0 before
** returning.
*/
static int sessionRebase(
  sqlite3_rebaser *p,             /* Rebaser hash table */
  sqlite3_changeset_iter *pIter,  /* Input data */
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut,                     /* Context for xOutput callback */
  int *pnOut,                     /* OUT: Number of bytes in output changeset */
  void **ppOut                    /* OUT: Inverse of pChangeset */
){
  int rc = SQLITE_OK;
  u8 *aRec = 0;
  int nRec = 0;
  int bNew = 0;
  SessionTable *pTab = 0;
  SessionBuffer sOut = {0,0,0};

  while( SQLITE_ROW==sessionChangesetNext(pIter, &aRec, &nRec, &bNew) ){
    SessionChange *pChange = 0;
    int bDone = 0;

    if( bNew ){
      const char *zTab = pIter->zTab;
      for(pTab=p->grp.pList; pTab; pTab=pTab->pNext){
        if( 0==sqlite3_stricmp(pTab->zName, zTab) ) break;
      }
      bNew = 0;

      /* A patchset may not be rebased */
      if( pIter->bPatchset ){
        rc = SQLITE_ERROR;
      }

      /* Append a table header to the output for this new table */
      sessionAppendByte(&sOut, pIter->bPatchset ? 'P' : 'T', &rc);
      sessionAppendVarint(&sOut, pIter->nCol, &rc);
      sessionAppendBlob(&sOut, pIter->abPK, pIter->nCol, &rc);
      sessionAppendBlob(&sOut, (u8*)pIter->zTab, strlen(pIter->zTab)+1, &rc);
    }

    if( pTab && rc==SQLITE_OK ){
      int iHash = sessionChangeHash(pTab, 0, aRec, pTab->nChange);

      for(pChange=pTab->apChange[iHash]; pChange; pChange=pChange->pNext){
        if( sessionChangeEqual(pTab, 0, aRec, 0, pChange->aRecord) ){
          break;
        }
      }
    }

    if( pChange ){
      assert( pChange->op==SQLITE_DELETE || pChange->op==SQLITE_INSERT );
      switch( pIter->op ){
        case SQLITE_INSERT:
          if( pChange->op==SQLITE_INSERT ){
            bDone = 1;
            if( pChange->bIndirect==0 ){
              sessionAppendByte(&sOut, SQLITE_UPDATE, &rc);
              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
              sessionAppendBlob(&sOut, pChange->aRecord, pChange->nRecord, &rc);
              sessionAppendBlob(&sOut, aRec, nRec, &rc);
            }
          }
          break;

        case SQLITE_UPDATE:
          bDone = 1;
          if( pChange->op==SQLITE_DELETE ){
            if( pChange->bIndirect==0 ){
              u8 *pCsr = aRec;
              sessionSkipRecord(&pCsr, pIter->nCol);
              sessionAppendByte(&sOut, SQLITE_INSERT, &rc);
              sessionAppendByte(&sOut, pIter->bIndirect, &rc);
              sessionAppendRecordMerge(&sOut, pIter->nCol,
                  pCsr, nRec-(pCsr-aRec), 
                  pChange->aRecord, pChange->nRecord, &rc
              );
            }
          }else{
            sessionAppendPartialUpdate(&sOut, pIter,
                aRec, nRec, pChange->aRecord, pChange->nRecord, &rc
            );
          }
          break;

        default:
          assert( pIter->op==SQLITE_DELETE );
          bDone = 1;
          if( pChange->op==SQLITE_INSERT ){
            sessionAppendByte(&sOut, SQLITE_DELETE, &rc);
            sessionAppendByte(&sOut, pIter->bIndirect, &rc);
            sessionAppendRecordMerge(&sOut, pIter->nCol,
                pChange->aRecord, pChange->nRecord, aRec, nRec, &rc
            );
          }
          break;
      }
    }

    if( bDone==0 ){
      sessionAppendByte(&sOut, pIter->op, &rc);
      sessionAppendByte(&sOut, pIter->bIndirect, &rc);
      sessionAppendBlob(&sOut, aRec, nRec, &rc);
    }
    if( rc==SQLITE_OK && xOutput && sOut.nBuf>SESSIONS_STRM_CHUNK_SIZE ){
      rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
      sOut.nBuf = 0;
    }
    if( rc ) break;
  }

  if( rc!=SQLITE_OK ){
    sqlite3_free(sOut.aBuf);
    memset(&sOut, 0, sizeof(sOut));
  }

  if( rc==SQLITE_OK ){
    if( xOutput ){
      if( sOut.nBuf>0 ){
        rc = xOutput(pOut, sOut.aBuf, sOut.nBuf);
      }
    }else{
      *ppOut = (void*)sOut.aBuf;
      *pnOut = sOut.nBuf;
      sOut.aBuf = 0;
    }
  }
  sqlite3_free(sOut.aBuf);
  return rc;
}

/* 
** Create a new rebaser object.
*/
int sqlite3rebaser_create(sqlite3_rebaser **ppNew){
  int rc = SQLITE_OK;
  sqlite3_rebaser *pNew;

  pNew = sqlite3_malloc(sizeof(sqlite3_rebaser));
  if( pNew==0 ){
    rc = SQLITE_NOMEM;
  }else{
    memset(pNew, 0, sizeof(sqlite3_rebaser));
  }
  *ppNew = pNew;
  return rc;
}

/* 
** Call this one or more times to configure a rebaser.
*/
int sqlite3rebaser_configure(
  sqlite3_rebaser *p, 
  int nRebase, const void *pRebase
){
  sqlite3_changeset_iter *pIter = 0;   /* Iterator opened on pData/nData */
  int rc;                              /* Return code */
  rc = sqlite3changeset_start(&pIter, nRebase, (void*)pRebase);
  if( rc==SQLITE_OK ){
    rc = sessionChangesetToHash(pIter, &p->grp, 1);
  }
  sqlite3changeset_finalize(pIter);
  return rc;
}

/* 
** Rebase a changeset according to current rebaser configuration 
*/
int sqlite3rebaser_rebase(
  sqlite3_rebaser *p,
  int nIn, const void *pIn, 
  int *pnOut, void **ppOut 
){
  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */  
  int rc = sqlite3changeset_start(&pIter, nIn, (void*)pIn);

  if( rc==SQLITE_OK ){
    rc = sessionRebase(p, pIter, 0, 0, pnOut, ppOut);
    sqlite3changeset_finalize(pIter);
  }

  return rc;
}

/* 
** Rebase a changeset according to current rebaser configuration 
*/
int sqlite3rebaser_rebase_strm(
  sqlite3_rebaser *p,
  int (*xInput)(void *pIn, void *pData, int *pnData),
  void *pIn,
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut
){
  sqlite3_changeset_iter *pIter = 0;   /* Iterator to skip through input */  
  int rc = sqlite3changeset_start_strm(&pIter, xInput, pIn);

  if( rc==SQLITE_OK ){
    rc = sessionRebase(p, pIter, xOutput, pOut, 0, 0);
    sqlite3changeset_finalize(pIter);
  }

  return rc;
}

/* 
** Destroy a rebaser object 
*/
void sqlite3rebaser_delete(sqlite3_rebaser *p){
  if( p ){
    sessionDeleteTable(p->grp.pList);
    sqlite3_free(p);
  }
}

#endif /* SQLITE_ENABLE_SESSION && SQLITE_ENABLE_PREUPDATE_HOOK */

** DESTRUCTOR: sqlite3_changegroup
*/
void sqlite3changegroup_delete(sqlite3_changegroup*);

/*
** CAPI3REF: Apply A Changeset To A Database
**
** Apply a changeset or patchset to a database. These functions attempt to
** update the "main" database attached to handle db with the changes found in
** the changeset passed via the second and third arguments. 
**
** The fourth argument (xFilter) passed to these functions is the "filter
** callback". If it is not NULL, then for each table affected by at least one
** change in the changeset, the filter callback is invoked with
** the table name as the second argument, and a copy of the context pointer
** passed as the sixth argument as the first. If the "filter callback"
** returns zero, then no attempt is made to apply any changes to the table.
** Otherwise, if the return value is non-zero or the xFilter argument to
** is NULL, all changes related to the table are attempted.

**
** For each table that is not excluded by the filter callback, this function 
** tests that the target database contains a compatible table. A table is 
** considered compatible if all of the following are true:
**
** <ul>
**   <li> The table has the same name as the name recorded in the 

** actions are taken by sqlite3changeset_apply() depending on the value
** returned by each invocation of the conflict-handler function. Refer to
** the documentation for the three 
** [SQLITE_CHANGESET_OMIT|available return values] for details.
**
** <dl>
** <dt>DELETE Changes<dd>
**   For each DELETE change, the function checks if the target database 
**   contains a row with the same primary key value (or values) as the 
**   original row values stored in the changeset. If it does, and the values 
**   stored in all non-primary key columns also match the values stored in 
**   the changeset the row is deleted from the target database.
**
**   If a row with matching primary key values is found, but one or more of
**   the non-primary key fields contains a value different from the original

**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is 
**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
**   This includes the case where the INSERT operation is re-attempted because 
**   an earlier call to the conflict handler function returned 
**   [SQLITE_CHANGESET_REPLACE].
**
** <dt>UPDATE Changes<dd>
**   For each UPDATE change, the function checks if the target database 
**   contains a row with the same primary key value (or values) as the 
**   original row values stored in the changeset. If it does, and the values 
**   stored in all modified non-primary key columns also match the values
**   stored in the changeset the row is updated within the target database.
**
**   If a row with matching primary key values is found, but one or more of
**   the modified non-primary key fields contains a value different from an

** </dl>
**
** It is safe to execute SQL statements, including those that write to the
** table that the callback related to, from within the xConflict callback.
** This can be used to further customize the applications conflict
** resolution strategy.
**
** All changes made by these functions are enclosed in a savepoint transaction.
** If any other error (aside from a constraint failure when attempting to
** write to the target database) occurs, then the savepoint transaction is
** rolled back, restoring the target database to its original state, and an 
** SQLite error code returned.
**
** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
** may set (*ppRebase) to point to a "rebase" that may be used with the 
** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
** is set to the size of the buffer in bytes. It is the responsibility of the
** caller to eventually free any such buffer using sqlite3_free(). The buffer
** is only allocated and populated if one or more conflicts were encountered
** while applying the patchset. See comments surrounding the sqlite3_rebaser
** APIs for further details.
*/
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 */
);
int sqlite3changeset_apply_v2(
  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 */
  void **ppRebase, int *pnRebase
);

/* 
** CAPI3REF: Constants Passed To The Conflict Handler
**
** Values that may be passed as the second argument to a conflict-handler.
**
** <dl>

**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
** </dl>
*/
#define SQLITE_CHANGESET_OMIT       0
#define SQLITE_CHANGESET_REPLACE    1
#define SQLITE_CHANGESET_ABORT      2

/* 
** CAPI3REF: Rebasing changesets
**
** Suppose there is a site hosting a database in state S0. And that
** modifications are made that move that database to state S1 and a
** changeset recorded (the "local" changeset). Then, a changeset based
** on S0 is received from another site (the "remote" changeset) and 
** applied to the database. The database is then in state 
** (S1+"remote"), where the exact state depends on any conflict
** resolution decisions (OMIT or REPLACE) made while applying "remote".
** Rebasing a changeset is to update it to take those conflict 
** resolution decisions into account, so that the same conflicts
** do not have to be resolved elsewhere in the network. 
**
** For example, if both the local and remote changesets contain an
** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
**
**   local:  INSERT INTO t1 VALUES(1, 'v1');
**   remote: INSERT INTO t1 VALUES(1, 'v2');
**
** and the conflict resolution is REPLACE, then the INSERT change is
** removed from the local changeset (it was overridden). Or, if the
** conflict resolution was "OMIT", then the local changeset is modified
** to instead contain:
**
**           UPDATE t1 SET b = 'v2' WHERE a=1;
**
** Changes within the local changeset are rebased as follows:
**
** <dl>
** <dt>Local INSERT<dd>
**   This may only conflict with a remote INSERT. If the conflict 
**   resolution was OMIT, then add an UPDATE change to the rebased
**   changeset. Or, if the conflict resolution was REPLACE, add
**   nothing to the rebased changeset.
**
** <dt>Local DELETE<dd>
**   This may conflict with a remote UPDATE or DELETE. In both cases the
**   only possible resolution is OMIT. If the remote operation was a
**   DELETE, then add no change to the rebased changeset. If the remote
**   operation was an UPDATE, then the old.* fields of change are updated
**   to reflect the new.* values in the UPDATE.
**
** <dt>Local UPDATE<dd>
**   This may conflict with a remote UPDATE or DELETE. If it conflicts
**   with a DELETE, and the conflict resolution was OMIT, then the update
**   is changed into an INSERT. Any undefined values in the new.* record
**   from the update change are filled in using the old.* values from
**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
**   the UPDATE change is simply omitted from the rebased changeset.
**
**   If conflict is with a remote UPDATE and the resolution is OMIT, then
**   the old.* values are rebased using the new.* values in the remote
**   change. Or, if the resolution is REPLACE, then the change is copied
**   into the rebased changeset with updates to columns also updated by
**   the conflicting remote UPDATE removed. If this means no columns would 
**   be updated, the change is omitted.
** </dl>
**
** A local change may be rebased against multiple remote changes 
** simultaneously. If a single key is modified by multiple remote 
** changesets, they are combined as follows before the local changeset
** is rebased:
**
** <ul>
**    <li> If there has been one or more REPLACE resolutions on a
**         key, it is rebased according to a REPLACE.
**
**    <li> If there have been no REPLACE resolutions on a key, then
**         the local changeset is rebased according to the most recent
**         of the OMIT resolutions.
** </ul>
**
** Note that conflict resolutions from multiple remote changesets are 
** combined on a per-field basis, not per-row. This means that in the 
** case of multiple remote UPDATE operations, some fields of a single 
** local change may be rebased for REPLACE while others are rebased for 
** OMIT.
**
** In order to rebase a local changeset, the remote changeset must first
** be applied to the local database using sqlite3changeset_apply_v2() and
** the buffer of rebase information captured. Then:
**
** <ol>
**   <li> An sqlite3_rebaser object is created by calling 
**        sqlite3rebaser_create().
**   <li> The new object is configured with the rebase buffer obtained from
**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
**        If the local changeset is to be rebased against multiple remote
**        changesets, then sqlite3rebaser_configure() should be called
**        multiple times, in the same order that the multiple
**        sqlite3changeset_apply_v2() calls were made.
**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
**   <li> The sqlite3_rebaser object is deleted by calling
**        sqlite3rebaser_delete().
** </ol>
*/
typedef struct sqlite3_rebaser sqlite3_rebaser;

/*
** CAPIREF: Create a changeset rebaser object.
**
** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
** point to the new object and return SQLITE_OK. Otherwise, if an error
** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew) 
** to NULL. 
*/
int sqlite3rebaser_create(sqlite3_rebaser **ppNew);

/*
** CAPIREF: Configure a changeset rebaser object.
**
** Configure the changeset rebaser object to rebase changesets according
** to the conflict resolutions described by buffer pRebase (size nRebase
** bytes), which must have been obtained from a previous call to
** sqlite3changeset_apply_v2().
*/
int sqlite3rebaser_configure(
  sqlite3_rebaser*, 
  int nRebase, const void *pRebase
); 

/*
** CAPIREF: Rebase a changeset
**
** Argument pIn must point to a buffer containing a changeset nIn bytes
** in size. This function allocates and populates a buffer with a copy
** of the changeset rebased rebased according to the configuration of the
** rebaser object passed as the first argument. If successful, (*ppOut)
** is set to point to the new buffer containing the rebased changset and 
** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
** responsibility of the caller to eventually free the new buffer using
** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
** are set to zero and an SQLite error code returned.
*/
int sqlite3rebaser_rebase(
  sqlite3_rebaser*,
  int nIn, const void *pIn, 
  int *pnOut, void **ppOut 
);

/*
** CAPIREF: Delete a changeset rebaser object.
**
** Delete the changeset rebaser object and all associated resources. There
** should be one call to this function for each successful invocation
** of sqlite3rebaser_create().
*/
void sqlite3rebaser_delete(sqlite3_rebaser *p); 

/*
** CAPI3REF: Streaming Versions of API functions.
**
** The six streaming API xxx_strm() functions serve similar purposes to the 
** corresponding non-streaming API functions:
**
** <table border=1 style="margin-left:8ex;margin-right:8ex">

  ),
  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 */
);
int sqlite3changeset_apply_v2_strm(
  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 */
  void **ppRebase, int *pnRebase
);
int sqlite3changeset_concat_strm(
  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),

int sqlite3changegroup_add_strm(sqlite3_changegroup*, 
    int (*xInput)(void *pIn, void *pData, int *pnData),
    void *pIn
);
int sqlite3changegroup_output_strm(sqlite3_changegroup*,
    int (*xOutput)(void *pOut, const void *pData, int nData), 
    void *pOut
);
int sqlite3rebaser_rebase_strm(
  sqlite3_rebaser *pRebaser,
  int (*xInput)(void *pIn, void *pData, int *pnData),
  void *pIn,
  int (*xOutput)(void *pOut, const void *pData, int nData),
  void *pOut
);


/*
** Make sure we can call this stuff from C++.
*/
#ifdef __cplusplus
}
#endif

#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */

#  include "sqlite_tcl.h"
#else
#  include "tcl.h"
#  ifndef SQLITE_TCLAPI
#    define SQLITE_TCLAPI
#  endif
#endif

#ifndef SQLITE_AMALGAMATION
  typedef unsigned char u8;
#endif

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

  }

  *pnData = nRet;
  return SQLITE_OK;
}





static int SQLITE_TCLAPI testSqlite3changesetApply(
  int bV2,
  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;
  void *pRebase = 0;
  int nRebase = 0;

  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?"

  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 ){
    if( bV2==0 ){
      rc = sqlite3changeset_apply(db, nChangeset, pChangeset, 
          (objc==5)?test_filter_handler:0, test_conflict_handler, (void *)&ctx
      );
    }else{
      rc = sqlite3changeset_apply_v2(db, nChangeset, pChangeset, 
          (objc==5)?test_filter_handler:0, test_conflict_handler, (void *)&ctx,
          &pRebase, &nRebase
      );
    }
  }else{
    sStr.aData = (unsigned char*)pChangeset;
    sStr.nData = nChangeset;
    if( bV2==0 ){
      rc = sqlite3changeset_apply_strm(db, testStreamInput, (void*)&sStr,
          (objc==5) ? test_filter_handler : 0, 
          test_conflict_handler, (void *)&ctx
      );
    }else{
      rc = sqlite3changeset_apply_v2_strm(db, testStreamInput, (void*)&sStr,
          (objc==5) ? test_filter_handler : 0, 
          test_conflict_handler, (void *)&ctx,
          &pRebase, &nRebase
      );
    }
  }

  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc, 0);
  }else{
    Tcl_ResetResult(interp);
    if( bV2 && pRebase ){
      Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(pRebase, nRebase));
    }
  }
  sqlite3_free(pRebase);
  return TCL_OK;
}

/*
** sqlite3changeset_apply DB CHANGESET CONFLICT-SCRIPT ?FILTER-SCRIPT?
*/
static int SQLITE_TCLAPI test_sqlite3changeset_apply(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  return testSqlite3changesetApply(0, clientData, interp, objc, objv);
}
/*
** sqlite3changeset_apply_v2 DB CHANGESET CONFLICT-SCRIPT ?FILTER-SCRIPT?
*/
static int SQLITE_TCLAPI test_sqlite3changeset_apply_v2(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  return testSqlite3changesetApply(1, clientData, interp, objc, objv);
}

/*
** sqlite3changeset_apply_replace_all DB CHANGESET 
*/
static int SQLITE_TCLAPI test_sqlite3changeset_apply_replace_all(
  void * clientData,
  Tcl_Interp *interp,

  }
  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc, 0);
  }

  return TCL_OK;
}

/*
** tclcmd: CMD configure REBASE-BLOB
** tclcmd: CMD rebase CHANGESET
** tclcmd: CMD delete
*/
static int SQLITE_TCLAPI test_rebaser_cmd(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  struct RebaseSubcmd {
    const char *zSub;
    int nArg;
    const char *zMsg;
    int iSub;
  } aSub[] = {
    { "configure",    1, "REBASE-BLOB" }, /* 0 */
    { "delete",       0, ""            }, /* 1 */
    { "rebase",       1, "CHANGESET"   }, /* 2 */
    { 0 }
  };

  sqlite3_rebaser *p = (sqlite3_rebaser*)clientData;
  int iSub;
  int rc;

  if( objc<2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "SUBCOMMAND ...");
    return TCL_ERROR;
  }
  rc = Tcl_GetIndexFromObjStruct(interp, 
      objv[1], aSub, sizeof(aSub[0]), "sub-command", 0, &iSub
  );
  if( rc!=TCL_OK ) return rc;
  if( objc!=2+aSub[iSub].nArg ){
    Tcl_WrongNumArgs(interp, 2, objv, aSub[iSub].zMsg);
    return TCL_ERROR;
  }

  assert( iSub==0 || iSub==1 || iSub==2 );
  assert( rc==SQLITE_OK );
  switch( iSub ){
    case 0: {   /* configure */
      int nRebase = 0;
      unsigned char *pRebase = Tcl_GetByteArrayFromObj(objv[2], &nRebase);
      rc = sqlite3rebaser_configure(p, nRebase, pRebase);
      break;
    }

    case 1:     /* delete */
      Tcl_DeleteCommand(interp, Tcl_GetString(objv[0]));
      break;

    default: {  /* rebase */
      TestStreamInput sStr;                 /* Input stream */
      TestSessionsBlob sOut;                /* Output blob */

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

      if( sStr.nStream ){
        rc = sqlite3rebaser_rebase_strm(p, 
            testStreamInput, (void*)&sStr,
            testStreamOutput, (void*)&sOut
        );
      }else{
        rc = sqlite3rebaser_rebase(p, sStr.nData, sStr.aData, &sOut.n, &sOut.p);
      }

      if( rc==SQLITE_OK ){
        Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(sOut.p, sOut.n));
      }
      sqlite3_free(sOut.p);
      break;
    }
  }

  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc, 0);
  }
  return TCL_OK;
}

static void SQLITE_TCLAPI test_rebaser_del(void *clientData){
  sqlite3_rebaser *p = (sqlite3_rebaser*)clientData;
  sqlite3rebaser_delete(p);
}

/*
** tclcmd: sqlite3rebaser_create NAME
*/
static int SQLITE_TCLAPI test_sqlite3rebaser_create(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int rc;
  sqlite3_rebaser *pNew = 0;
  if( objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "NAME");
    return SQLITE_ERROR;
  }

  rc = sqlite3rebaser_create(&pNew);
  if( rc!=SQLITE_OK ){
    return test_session_error(interp, rc, 0);
  }

  Tcl_CreateObjCommand(interp, Tcl_GetString(objv[1]), test_rebaser_cmd,
      (ClientData)pNew, test_rebaser_del
  );
  Tcl_SetObjResult(interp, objv[1]);
  return TCL_OK;
}

int TestSession_Init(Tcl_Interp *interp){
  struct Cmd {
    const char *zCmd;
    Tcl_ObjCmdProc *xProc;
  } aCmd[] = {
    { "sqlite3session", test_sqlite3session },
    { "sqlite3session_foreach", test_sqlite3session_foreach },
    { "sqlite3changeset_invert", test_sqlite3changeset_invert },
    { "sqlite3changeset_concat", test_sqlite3changeset_concat },
    { "sqlite3changeset_apply", test_sqlite3changeset_apply },
    { "sqlite3changeset_apply_v2", test_sqlite3changeset_apply_v2 },
    { "sqlite3changeset_apply_replace_all", 
      test_sqlite3changeset_apply_replace_all },
    { "sql_exec_changeset", test_sql_exec_changeset },
    { "sqlite3rebaser_create", test_sqlite3rebaser_create },
  };
  int i;

  for(i=0; i<sizeof(aCmd)/sizeof(struct Cmd); i++){
    struct Cmd *p = &aCmd[i];
    Tcl_CreateObjCommand(interp, p->zCmd, p->xProc, 0, 0);
  }

  return TCL_OK;
}

#endif /* SQLITE_TEST && SQLITE_SESSION && SQLITE_PREUPDATE_HOOK */