SQLite

  return rc;
}

static void tvfsShmBarrier(sqlite3_file *pFile){
  TestvfsFd *pFd = tvfsGetFd(pFile);
  Testvfs *p = (Testvfs *)(pFd->pVfs->pAppData);

  if( p->pScript && p->mask&TESTVFS_SHMBARRIER_MASK ){
    const char *z = pFd->pShm ? pFd->pShm->zFile : "";
    tvfsExecTcl(p, "xShmBarrier", Tcl_NewStringObj(z, -1), pFd->pShmId, 0, 0);
  }

  if( p->isFullshm ){
    sqlite3OsShmBarrier(pFd->pReal);
    return;
  }






}

static int tvfsShmUnmap(
  sqlite3_file *pFile,
  int deleteFlag
){
  int rc = SQLITE_OK;

  p->mask = TESTVFS_ALL_MASK;

  sqlite3_vfs_register(pVfs, isDefault);

  return TCL_OK;

 bad_args:
  Tcl_WrongNumArgs(interp, 1, objv, "VFSNAME ?-noshm BOOL? ?-fullshm BOOL? ?-default BOOL? ?-mxpathname INT? ?-szosfile INT? ?-iversion INT?");
  return TCL_ERROR;
}

int Sqlitetestvfs_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "testvfs", testvfs_cmd, 0, 0);
  return TCL_OK;
}

#endif

  }
  return $chan
}

# Execute a command in a child testfixture process, connected by two-way
# channel $chan. Return the result of the command, or an error message.
#
proc testfixture {chan cmd args} {

  if {[llength $args] == 0} {
    fconfigure $chan -blocking 1
    puts $chan $cmd
    puts $chan OVER

    set r ""
    while { 1 } {
      set line [gets $chan]
      if { $line == "OVER" } { 
        set res [lindex $r 1]
        if { [lindex $r 0] } { error $res }
        return $res
      }
      if {[eof $chan]} {
        return "ERROR: Child process hung up"
      }
      append r $line
    }
    return $r
  } else {
    set ::tfnb($chan) ""
    fconfigure $chan -blocking 0 -buffering none
    puts $chan $cmd
    puts $chan OVER
    fileevent $chan readable [list testfixture_script_cb $chan [lindex $args 0]]
    return ""
  }
}

proc testfixture_script_cb {chan script} {
  if {[eof $chan]} {
    append ::tfnb($chan) "ERROR: Child process hung up"
    set line "OVER"
  } else {
    set line [gets $chan]
  }

  if { $line == "OVER" } {
    uplevel #0 $script [list [lindex $::tfnb($chan) 1]]
    unset ::tfnb($chan)
    fileevent $chan readable ""
  } else {
    append ::tfnb($chan) $line
  }
}

proc testfixture_nb_cb {varname chan} {
  if {[eof $chan]} {
    append ::tfnb($chan) "ERROR: Child process hung up"
    set line "OVER"

# 2015 Mar 17
#
# 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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
source $testdir/wal_common.tcl

ifcapable !wal {finish_test ; return }
if {$::tcl_platform(platform)!="unix"} { finish_test ; return }
set testprefix walblock

catch { db close }
testvfs tvfs -fullshm 1
foreach f [glob test.db*] { forcedelete $f }

sqlite3 db test.db -vfs tvfs
do_execsql_test 1.1.0 {
  CREATE TABLE t1(x, y);
  INSERT INTO t1 VALUES(1, 2);
  INSERT INTO t1 VALUES(3, 4);
  INSERT INTO t1 VALUES(5, 6);
  PRAGMA journal_mode = wal;
  INSERT INTO t1 VALUES(7, 8);
} {wal}

do_test 1.1.1 { 
  lsort [glob test.db*] 
} {test.db test.db-shm test.db-wal}

do_test 1.1.2 { 
  set C [launch_testfixture]
  testfixture $C {
    sqlite3 db test.db
    db eval { SELECT * FROM t1 }
  }
} {1 2 3 4 5 6 7 8}

do_test 1.1.3 { 
  set ::out [list]
  testfixture $C {
    db eval { SELECT * FROM t1 }
  } [list set ::out]
  set ::out
} {}

do_test 1.1.4 { 
  vwait ::out
  set ::out
} {1 2 3 4 5 6 7 8}

#
# Test that if a read client cannot read the wal-index header because a
# write client is in the middle of updating it, the reader blocks until
# the writer finishes.
#
#   1. Open a write transaction using client [db] in this process.
#
#   2. Attempt to commit the write transaction. Intercept the xShmBarrier()
#      call made by the writer between updating the two copies of the
#      wal-index header.
#
#   3. Within the xShmBarrier() callback, make an asynchronous request to
#      the other process to read from the database. It should block, as it
#      cannot get read the wal-index header.
#
#   4. Still in xShmBarrier(), wait for 5 seconds. Check that the other
#      process has not answered the request.
#
#   5: Finish committing the transaction. Then wait for 0.5 seconds more.
#      Ensure that the second process has by this stage read the database
#      and that the snapshot it read included the transaction committed in
#      step (4).
#
do_execsql_test 1.2.1 {
  BEGIN;
    INSERT INTO t1 VALUES(9, 10);
} {}

tvfs script barrier_callback
tvfs filter xShmBarrier
proc barrier_callback {method args} {
  set ::out ""
  testfixture $::C { db eval { SELECT * FROM t1 } } {set ::out}

  do_test "1.2.2.(blocking 5 seconds)" { 
    set ::continue 0
    after 5000 {set ::continue 1}
    vwait ::continue
    set ::out 
  } {}
}

execsql COMMIT

do_test "1.2.3.(blocking 0.5 seconds)" { 
  set ::continue 0
  after 500 {set ::continue 1}
  vwait ::continue
  set ::out 
} {1 2 3 4 5 6 7 8 9 10}


finish_test