SQLite

# 2021 November 06
#
# 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.
#
#***********************************************************************
#

source [file join [file dirname [info script]] rbu_common.tcl]
set ::testprefix rbuexlock

db close
sqlite3_shutdown
sqlite3_config_uri 1

# Create a simple RBU database. That expects to write to a table:
#
#   CREATE TABLE t1(a INTEGER PRIMARY KEY, b, c);
#
proc create_rbu {filename} {
  forcedelete $filename
  sqlite3 rbu1 $filename  
  rbu1 eval {
    CREATE TABLE data_t1(a, b, c, rbu_control);
    INSERT INTO data_t1 VALUES(10, random(), random(), 0);
    INSERT INTO data_t1 VALUES(20, random(), random(), 0);
    INSERT INTO data_t1 VALUES(30, random(), random(), 0);
    INSERT INTO data_t1 VALUES(40, random(), random(), 0);
    INSERT INTO data_t1 VALUES(50, random(), random(), 0);
    INSERT INTO data_t1 VALUES(60, random(), random(), 0);
    INSERT INTO data_t1 VALUES(70, random(), random(), 0);
    INSERT INTO data_t1 VALUES(80, random(), random(), 0);
  }
  rbu1 close
  return $filename
}

reset_db

do_execsql_test 1.0 {
  CREATE TABLE t1(a PRIMARY KEY, b INT, c INT);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  INSERT INTO t1 VALUES(1, 2, 3);
}
create_rbu rbu1.db

do_test 1.1.0 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=1 rbu1.db
  rbu step
} SQLITE_OK
do_catchsql_test 1.1.1 { SELECT * FROM t1 } {0 {1 2 3}}

do_test 1.2.0 {
  for {set ii 0} {$ii < 10} {incr ii} {
    rbu step
  }
  rbu step
} SQLITE_OK
do_catchsql_test 1.2.1 { SELECT * FROM t1 } {0 {1 2 3}}
do_test 1.2.2 {
  db eval {PRAGMA journal_mode}
} {delete}

do_test 1.3.0 {
  while {[file exists test.db-wal]==0} {
    rbu step
  }
} {}
do_catchsql_test 1.3.1 { SELECT * FROM t1 } {1 {database is locked}}
do_test 1.3.2 {
  db eval {PRAGMA journal_mode}
} {delete}


do_test 1.4.0 {
  rbu step
} SQLITE_OK
do_catchsql_test 1.4.1 { SELECT * FROM t1 } {1 {database is locked}}
do_test 1.4.2 {
  db eval {PRAGMA journal_mode}
} {delete}


rbu close

do_test 1.5.0 {
  file exists test.db-wal
} {1}
do_test 1.5.1 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=1 rbu1.db
  file exists test.db-wal
} 1
do_catchsql_test 1.5.2 { SELECT * FROM t1 } {1 {database is locked}}
do_test 1.5.2 {
  db eval {PRAGMA journal_mode}
} {delete}


do_test 1.6.0 {
  rbu step
} SQLITE_OK
do_catchsql_test 1.6.1 { SELECT * FROM t1 } {1 {database is locked}}
do_test 1.6.2 {
  db eval {PRAGMA journal_mode}
} {delete}

do_test 1.7.0 {
  while {[rbu step]=="SQLITE_OK"} {}
  rbu close
} SQLITE_DONE
do_catchsql_test 1.7.2 { SELECT count(*) FROM t1 } {0 9}
do_test 1.7.2 {
  db eval {PRAGMA journal_mode}
} {delete}

reset_db
do_execsql_test 2.0 {
  CREATE TABLE t1(a PRIMARY KEY, b INT, c INT);
  CREATE INDEX t1b ON t1(b);
  CREATE INDEX t1c ON t1(c);
  INSERT INTO t1 VALUES(1, 2, 3);
}
create_rbu rbu1.db

do_test 2.1.0 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
  rbu step
} SQLITE_OK
do_catchsql_test 2.1.1 { SELECT * FROM t1 } {0 {1 2 3}}

do_test 2.2.0 {
  for {set ii 0} {$ii < 10} {incr ii} {
    rbu step
  }
  rbu step
} SQLITE_OK
do_catchsql_test 2.2.1 { SELECT * FROM t1 } {0 {1 2 3}}

do_test 2.3.0 {
  while {[file exists test.db-wal]==0} {
    rbu step
  }
} {}
do_test 2.3.1 {
  llength [db eval {SELECT * FROM t1}]
} {27}
do_test 2.3.2 {
  db eval {PRAGMA journal_mode}
} {wal}

do_test 2.4.0 {
  rbu step
} SQLITE_OK
do_test 2.4.1 {
  llength [db eval  {SELECT * FROM t1}]
} {27}
do_test 2.4.2 {
  db eval {PRAGMA journal_mode}
} {wal}

rbu close

do_test 2.5.0 {
  db eval {PRAGMA journal_mode}
} {wal}
do_execsql_test 2.5.1 {
  DELETE FROM t1;
} {}

create_rbu rbu1.db
do_test 3.1.0 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
  rbu step
} SQLITE_ERROR

do_test 3.1.1 {
  set rc [catch {rbu close} msg]
  lappend rc $msg
} {1 {SQLITE_ERROR - cannot update wal mode database}}
db eval {PRAGMA journal_mode=DELETE}

create_rbu rbu1.db
do_test 3.2.0 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
  rbu step
} SQLITE_OK

do_test 3.3.1 {
  set rc [catch {rbu close} msg]
  lappend rc $msg
} {0 SQLITE_OK}

db close
create_rbu rbu1.db
do_test 3.4.0 {
  sqlite3rbu rbu file:test.db?rbu_exclusive_checkpoint=0 rbu1.db
  rbu step
} SQLITE_OK
rbu close


finish_test

/*
** Swap two objects of type TYPE.
*/
#if !defined(SQLITE_AMALGAMATION)
# define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}
#endif

/*
** Name of the URI option that causes RBU to take an exclusive lock as
** part of the incremental checkpoint operation.
*/
#define RBU_EXCLUSIVE_CHECKPOINT "rbu_exclusive_checkpoint"


/*
** The rbu_state table is used to save the state of a partially applied
** update so that it can be resumed later. The table consists of integer
** keys mapped to values as follows:
**
** RBU_STATE_STAGE:

  return pRet;
}


/*
** Open the database handle and attach the RBU database as "rbu". If an
** error occurs, leave an error code and message in the RBU handle.
**
** If argument dbMain is not NULL, then it is a database handle already
** open on the target database. Use this handle instead of opening a new
** one.
*/
static void rbuOpenDatabase(sqlite3rbu *p, sqlite3 *dbMain, int *pbRetry){
  assert( p->rc || (p->dbMain==0 && p->dbRbu==0) );
  assert( p->rc || rbuIsVacuum(p) || p->zTarget!=0 );
  assert( dbMain==0 || rbuIsVacuum(p)==0 );

  /* Open the RBU database */
  p->dbRbu = rbuOpenDbhandle(p, p->zRbu, 1);
  p->dbMain = dbMain;

  if( p->rc==SQLITE_OK && rbuIsVacuum(p) ){
    sqlite3_file_control(p->dbRbu, "main", SQLITE_FCNTL_RBUCNT, (void*)p);
    if( p->zState==0 ){
      const char *zFile = sqlite3_db_filename(p->dbRbu, "main");
      p->zState = rbuMPrintf(p, "file://%s-vacuum?modeof=%s", zFile, zFile);
    }

  iOff = (i64)(pFrame->iDbPage-1) * p->pgsz;
  p->rc = pDb->pMethods->xWrite(pDb, p->aBuf, p->pgsz, iOff);
}


/*
** Take an EXCLUSIVE lock on the database file. Return SQLITE_OK if
** successful, or an SQLite error code otherwise.
*/
static int rbuLockDatabase(sqlite3 *db){
  int rc = SQLITE_OK;
  sqlite3_file *fd = 0;
  sqlite3_file_control(db, "main", SQLITE_FCNTL_FILE_POINTER, &fd);

  if( fd->pMethods ){
    rc = fd->pMethods->xLock(fd, SQLITE_LOCK_SHARED);
    if( rc==SQLITE_OK ){
      rc = fd->pMethods->xLock(fd, SQLITE_LOCK_EXCLUSIVE);
    }
  }
  return rc;
}

/*
** Return true if the database handle passed as the only argument
** was opened with the rbu_exclusive_checkpoint=1 URI parameter
** specified. Or false otherwise.
*/
static int rbuExclusiveCheckpoint(sqlite3 *db){
  const char *zUri = sqlite3_db_filename(db, 0);
  return sqlite3_uri_boolean(zUri, RBU_EXCLUSIVE_CHECKPOINT, 0);
}

#if defined(_WIN32_WCE)
static LPWSTR rbuWinUtf8ToUnicode(const char *zFilename){
  int nChar;
  LPWSTR zWideFilename;

    /* Move the *-oal file to *-wal. At this point connection p->db is
    ** holding a SHARED lock on the target database file (because it is
    ** in WAL mode). So no other connection may be writing the db. 
    **
    ** In order to ensure that there are no database readers, an EXCLUSIVE
    ** lock is obtained here before the *-oal is moved to *-wal.
    */
    sqlite3 *dbMain = 0;

    rbuFileSuffix3(zBase, zWal);
    rbuFileSuffix3(zBase, zOal);

    /* Re-open the databases. */
    rbuObjIterFinalize(&p->objiter);
    sqlite3_close(p->dbRbu);
    sqlite3_close(p->dbMain);
    p->dbMain = 0;
    p->dbRbu = 0;

    dbMain = rbuOpenDbhandle(p, p->zTarget, 1);
    if( dbMain ){
      assert( p->rc==SQLITE_OK );
      p->rc = rbuLockDatabase(dbMain);
    }

    if( p->rc==SQLITE_OK ){
#if defined(_WIN32_WCE)
      {
        LPWSTR zWideOal;
        LPWSTR zWideWal;

        zWideOal = rbuWinUtf8ToUnicode(zOal);
        if( zWideOal ){

        }else{
          p->rc = SQLITE_IOERR_NOMEM;
        }
      }
#else
      p->rc = rename(zOal, zWal) ? SQLITE_IOERR : SQLITE_OK;
#endif
    }

    if( p->rc!=SQLITE_OK 
     || rbuIsVacuum(p) 
     || rbuExclusiveCheckpoint(dbMain)==0 
    ){
      sqlite3_close(dbMain);
      dbMain = 0;
    }

    if( p->rc==SQLITE_OK ){
      rbuOpenDatabase(p, dbMain, 0);
      rbuSetupCheckpoint(p, 0);

    }
  }

  sqlite3_free(zWal);
  sqlite3_free(zOal);
}

      /* If the first attempt to open the database file fails and the bRetry
      ** flag it set, this means that the db was not opened because it seemed
      ** to be a wal-mode db. But, this may have happened due to an earlier
      ** RBU vacuum operation leaving an old wal file in the directory.
      ** If this is the case, it will have been checkpointed and deleted
      ** when the handle was closed and a second attempt to open the 
      ** database may succeed.  */
      rbuOpenDatabase(p, 0, &bRetry);
      if( bRetry ){
        rbuOpenDatabase(p, 0, 0);
      }
    }

    if( p->rc==SQLITE_OK ){
      pState = rbuLoadState(p);
      assert( pState || p->rc!=SQLITE_OK );
      if( p->rc==SQLITE_OK ){

          if( p->rc==SQLITE_OK ){
            rbuSetupOal(p, pState);
          }
        }
      }else if( p->eStage==RBU_STAGE_MOVE ){
        /* no-op */
      }else if( p->eStage==RBU_STAGE_CKPT ){
        if( !rbuIsVacuum(p) && rbuExclusiveCheckpoint(p->dbMain) ){
          /* If the rbu_exclusive_checkpoint=1 URI parameter was specified
          ** and an incremental checkpoint is being resumed, attempt an
          ** exclusive lock on the db file. If this fails, so be it.  */
          p->eStage = RBU_STAGE_DONE;
          rbuLockDatabase(p->dbMain);
          p->eStage = RBU_STAGE_CKPT;
        }
        rbuSetupCheckpoint(p, pState);
      }else if( p->eStage==RBU_STAGE_DONE ){
        p->rc = SQLITE_DONE;
      }else{
        p->rc = SQLITE_CORRUPT;
      }
    }

*/
sqlite3rbu *sqlite3rbu_open(
  const char *zTarget, 
  const char *zRbu,
  const char *zState
){
  if( zTarget==0 || zRbu==0 ){ return rbuMisuseError(); }

  return openRbuHandle(zTarget, zRbu, zState);
}

/*
** Open a handle to begin or resume an RBU VACUUM operation.
*/
sqlite3rbu *sqlite3rbu_vacuum(