SQLite

**
*************************************************************************
**
** This file contains the implementation of some Tcl commands used to
** test that sqlite3 database handles may be concurrently accessed by 
** multiple threads. Right now this only works on unix.
**
** $Id: test_thread.c,v 1.3 2007/09/10 06:23:54 danielk1977 Exp $
*/

#include "sqliteInt.h"

#if SQLITE_THREADSAFE && defined(TCL_THREADS)

#include <tcl.h>

  rc = Tcl_Eval(interp, p->zScript);
  pRes = Tcl_GetObjResult(interp);
  pList = Tcl_NewObj();
  Tcl_IncrRefCount(pList);
  Tcl_IncrRefCount(pRes);

  if( rc!=TCL_OK ){
    Tcl_ListObjAppendElement(interp, pList, Tcl_NewStringObj("error", -1));
    Tcl_ListObjAppendElement(interp, pList, pRes);
    postToParent(p, pList);
    Tcl_DecrRefCount(pList);
    pList = Tcl_NewObj();
  }

  Tcl_ListObjAppendElement(interp, pList, Tcl_NewStringObj("set", -1));

  Tcl_ListObjAppendElement(interp, pList, Tcl_NewStringObj(p->zVarname, -1));
  Tcl_ListObjAppendElement(interp, pList, pRes);
  postToParent(p, pList);

  ckfree((void *)p);
  Tcl_DecrRefCount(pList);
  Tcl_DecrRefCount(pRes);
  Tcl_DeleteInterp(interp);
  return;

  memcpy(pEvent->zScript, zMsg, nMsg+1);
  pEvent->interp = p->interp;
  Tcl_ThreadQueueEvent(p->parent, (Tcl_Event *)pEvent, TCL_QUEUE_TAIL);
  Tcl_ThreadAlert(p->parent);

  return TCL_OK;
}

static int xBusy(void *pArg, int nBusy){
  sqlite3_sleep(50);
  return 1;             /* Try again... */
}

static int sqlthread_open(
  ClientData clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  int sqlite3TestMakePointerStr(Tcl_Interp *interp, char *zPtr, void *p);

  const char *zFilename;
  sqlite3 *db;
  int rc;
  char zBuf[100];
  extern void Md5_Register(sqlite3*);

  zFilename = Tcl_GetString(objv[2]);
  rc = sqlite3_open(zFilename, &db);
  Md5_Register(db);
  sqlite3_busy_handler(db, xBusy, 0);
  
  if( sqlite3TestMakePointerStr(interp, zBuf, db) ) return TCL_ERROR;
  Tcl_AppendResult(interp, zBuf, 0);

  return TCL_OK;
}


/*
** Dispatch routine for the sub-commands of [sqlthread].
*/
static int sqlthread_proc(
  ClientData clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  struct SubCommand {
    char *zName;
    Tcl_ObjCmdProc *xProc;
    int nArg;
    char *zUsage;
  } aSub[] = {
    {"parent", sqlthread_parent, 1, "SCRIPT"},
    {"spawn",  sqlthread_spawn,  2, "VARNAME SCRIPT"},
    {"open",   sqlthread_open,   1, "DBNAME"},
    {0, 0, 0}
  };
  struct SubCommand *pSub;
  int rc;
  int iIndex;

  if( objc<2 ){

# 2007 September 7
#
# 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.
#
#***********************************************************************
#
# $Id: thread001.test,v 1.3 2007/09/10 06:23:54 danielk1977 Exp $

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

if {[info commands sqlthread] eq ""} {
  puts -nonewline "Skipping thread-safety tests - "
  puts            " not running a threadsafe sqlite/tcl build"
  puts -nonewline "Both SQLITE_THREADSAFE and TCL_THREADS must be defined when"
  puts            " building testfixture"
  finish_test
  return
}









set ::NTHREAD 10














# The following script is sourced by every thread spawned using 
# [sqlthread spawn]:
set thread_procs {


  # Execute the supplied SQL using database handle $::DB.
  #
  proc execsql {sql} {
    set res [list]
    set ::STMT [sqlite3_prepare $::DB $sql -1 dummy_tail]
    while {[sqlite3_step $::STMT] eq "SQLITE_ROW"} {

  proc do_test {name script result} {
    set res [eval $script]
    if {$res ne $result} {
      error "$name failed: expected \"$result\" got \"$res\""
    }
  }
}

proc thread_spawn {varname args} {
  sqlthread spawn $varname [join $args ;]
}

#########################################################################
# End of infrastruture. Start of test cases.
#########################################################################


# Run this test twice: Once with all threads using the same database
# connection, and once with each using it's own connection.
#
foreach {dbconfig tn} [list "set ::DB $::DB" 1 "" 2] {

  # Empty the database.
  #
  catchsql { DROP TABLE ab; }

  # Set up a database and a schema. The database contains a single
  # table with two columns. The first column ("a") is an INTEGER PRIMARY 
  # KEY. The second contains the md5sum of all rows in the table with
  # a smaller value stored in column "a".
  #
  do_test thread001.$tn.1 {
    execsql {
      CREATE TABLE ab(a INTEGER PRIMARY KEY, b);
      CREATE INDEX ab_i ON ab(b);
      INSERT INTO ab SELECT NULL, md5sum(a, b) FROM ab;
      SELECT count(*) FROM ab;
    }
  } {1}
  do_test thread001.$tn.2 {
    execsql {
      SELECT 
        (SELECT md5sum(a, b) FROM ab WHERE a < (SELECT max(a) FROM ab)) ==
        (SELECT b FROM ab WHERE a = (SELECT max(a) FROM ab))
    }
  } {1}
  do_test thread001.$tn.3 {
    execsql { PRAGMA integrity_check }
  } {ok}
  
  set thread_program {
    set needToClose 0
    if {![info exists ::DB]} {
      set ::DB [sqlthread open test.db]
      set needToClose 1
    }
  
    for {set i 0} {$i < 100} {incr i} {
      # Test that the invariant is true.
      do_test t1 {
        execsql {
          SELECT 
            (SELECT md5sum(a, b) FROM ab WHERE a < (SELECT max(a) FROM ab)) ==
            (SELECT b FROM ab WHERE a = (SELECT max(a) FROM ab))
        }
      } {1}
  
      # Add another row to the database.
      execsql { INSERT INTO ab SELECT NULL, md5sum(a, b) FROM ab }
    }
  
    if {$needToClose} {
      sqlite3_close $::DB
    }
  
    list OK

  }
  
  # Kick off $::NTHREAD threads:
  #
  array unset finished
  for {set i 0} {$i < $::NTHREAD} {incr i} {
    thread_spawn finished($i) $dbconfig $thread_procs $thread_program
  }
  
  # Wait for all threads to finish,  then check they all returned "OK".
  #
  for {set i 0} {$i < $::NTHREAD} {incr i} {
    if {![info exists finished($i)]} {
      vwait finished($i)
    }
    do_test thread001.$tn.4.$i {
      set ::finished($i)
    } OK
  }
  
  # Check the database still looks Ok.
  #
  do_test thread001.$tn.5 {
    execsql { SELECT count(*) FROM ab; }
  } [expr {1 + $::NTHREAD*100}]
  do_test thread001.$tn.6 {
    execsql {
      SELECT 
        (SELECT md5sum(a, b) FROM ab WHERE a < (SELECT max(a) FROM ab)) ==
        (SELECT b FROM ab WHERE a = (SELECT max(a) FROM ab))
    }
  } {1}
  do_test thread001.$tn.7 {
    execsql { PRAGMA integrity_check }
  } {ok}
}







finish_test