SQLite

/*
** 2004 April 6
**
** 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: btree.c,v 1.304 2006/01/20 16:32:04 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

  #define lockTable(a,b,c) SQLITE_OK
  #define unlockAllTables(a)
  #define restoreOrClearCursorPosition(a,b) SQLITE_OK
  #define saveAllCursors(a,b,c) SQLITE_OK

#else

static void releasePage(MemPage *pPage);

/*
** Save the current cursor position in the variables BtCursor.nKey 
** and BtCursor.pKey. The cursor's state is set to CURSOR_REQUIRESEEK.
*/
static int saveCursorPosition(BtCursor *pCur){
  int rc;

    }else{
      rc = SQLITE_NOMEM;
    }
  }
  assert( !pCur->pPage->intKey || !pCur->pKey );

  /* Todo: Should we drop the reference to pCur->pPage here? */
  releasePage(pCur->pPage);
  pCur->pPage = 0;

  if( rc==SQLITE_OK ){
    pCur->eState = CURSOR_REQUIRESEEK;
  }

  return rc;
}

** is active this routine is a no-op.
**
** All cursors will be invalidated by this operation.  Any attempt
** to use a cursor that was open at the beginning of this operation
** will result in an error.
*/
int sqlite3BtreeRollbackStmt(Btree *p){
  int rc = SQLITE_OK;
  BtShared *pBt = p->pBt;
  sqlite3MallocDisallow();
  if( pBt->inStmt && !pBt->readOnly ){
    rc = sqlite3pager_stmt_rollback(pBt->pPager);
    assert( countWriteCursors(pBt)==0 );
    pBt->inStmt = 0;
  }
  sqlite3MallocAllow();
  return rc;
}

/*
** Default key comparison function to be used if no comparison function
** is specified on the sqlite3BtreeCursor() call.
*/

*/
static int moveToRoot(BtCursor *pCur){
  MemPage *pRoot;
  int rc = SQLITE_OK;
  BtShared *pBt = pCur->pBtree->pBt;

  restoreOrClearCursorPosition(pCur, 0);

  pRoot = pCur->pPage;
  if( pRoot && pRoot->pgno==pCur->pgnoRoot ){
    assert( pRoot->isInit );
  }else{
    if( 
      SQLITE_OK!=(rc = getAndInitPage(pBt, pCur->pgnoRoot, &pRoot, 0))
    ){
      pCur->eState = CURSOR_INVALID;
      return rc;

** Advance the cursor to the next entry in the database.  If
** successful then set *pRes=0.  If the cursor
** was already pointing to the last entry in the database before
** this routine was called, then set *pRes=1.
*/
int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
  int rc;
  MemPage *pPage;

#ifndef SQLITE_OMIT_SHARED_CACHE
  rc = restoreOrClearCursorPosition(pCur, 1);
  if( rc!=SQLITE_OK ){
    return rc;
  }
  if( pCur->skip>0 ){
    pCur->skip = 0;
    *pRes = 0;
    return SQLITE_OK;
  }
  pCur->skip = 0;
#endif 

  assert( pRes!=0 );
  pPage = pCur->pPage;
  if( CURSOR_INVALID==pCur->eState ){
    *pRes = 1;
    return SQLITE_OK;
  }
  assert( pPage->isInit );
  assert( pCur->idx<pPage->nCell );

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.247 2006/01/20 16:32:04 danielk1977 Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
#include "os.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

        rc = sqlite3OsRead(pPager->fd, PGHDR_TO_DATA(pPg),
                              pPager->pageSize);
      }
      TRACE3("FETCH %d page %d\n", PAGERID(pPager), pPg->pgno);
      CODEC(pPager, PGHDR_TO_DATA(pPg), pPg->pgno, 3);
      if( rc!=SQLITE_OK ){
        i64 fileSize;
        int rc2 = sqlite3OsFileSize(pPager->fd, &fileSize);
        if( rc2!=SQLITE_OK || fileSize>=pgno*pPager->pageSize ){
	  /* An IO error occured in one of the the sqlite3OsSeek() or
          ** sqlite3OsRead() calls above. Unreference the page and then
          ** set it's page number to 0 (0 means "not a page").
          */
          sqlite3pager_unref(PGHDR_TO_DATA(pPg));
          pPg->pgno = 0;
          return rc;
        }else{
          clear_simulated_io_error();
          memset(PGHDR_TO_DATA(pPg), 0, pPager->pageSize);
        }
      }else{
        TEST_INCR(pPager->nRead);
      }

    assert( p->aOp[p->nOp-1].opcode==OP_Noop );
    assert( p->aOp[p->nOp-1].p3!=0 );
    assert( p->aOp[p->nOp-1].p3type==P3_DYNAMIC );
    db->xProfile(db->pProfileArg, p->aOp[p->nOp-1].p3, elapseTime);
  }
#endif

  sqlite3Error(p->db, rc, 0);
  p->rc = sqlite3ApiExit(p->db, p->rc);
  return rc;
}

/*
** Extract the user data from a sqlite3_context structure and return a
** pointer to it.

      if( !isReadOnly ){
        if( p->rc==SQLITE_NOMEM && isStatement ){
          xFunc = sqlite3BtreeRollbackStmt;
        }else{
          /* We are forced to roll back the active transaction. Before doing
          ** so, abort any other statements this handle currently has active.
          */
          abortOtherActiveVdbes(p);
          sqlite3RollbackAll(db);
          db->autoCommit = 1;
        }
      }
    }
  
    /* If the auto-commit flag is set and this is the only active vdbe, then
    ** we do either a commit or rollback of the current transaction. 

        ** is required.
        */
        int rc = vdbeCommit(db);
        if( rc==SQLITE_BUSY ){
          return SQLITE_BUSY;
        }else if( rc!=SQLITE_OK ){
          p->rc = rc;
          sqlite3RollbackAll(db);
        }else{
          sqlite3CommitInternalChanges(db);
        }
      }else{
        sqlite3RollbackAll(db);
      }
    }else if( !xFunc ){
      if( p->rc==SQLITE_OK || p->errorAction==OE_Fail ){
        xFunc = sqlite3BtreeCommitStmt;
      }else if( p->errorAction==OE_Abort ){
        xFunc = sqlite3BtreeRollbackStmt;
      }else{
        abortOtherActiveVdbes(p);
        sqlite3RollbackAll(db);
        db->autoCommit = 1;
      }
    }
  
    /* If xFunc is not NULL, then it is one of sqlite3BtreeRollbackStmt or
    ** sqlite3BtreeCommitStmt. Call it once on each backend. If an error occurs
    ** and the return code is still SQLITE_OK, set the return code to the new

  /* If the VDBE has be run even partially, then transfer the error code
  ** and error message from the VDBE into the main database structure.  But
  ** if the VDBE has just been set to run but has not actually executed any
  ** instructions yet, leave the main database error information unchanged.
  */
  if( p->pc>=0 ){
    if( p->zErrMsg ){
      sqlite3* db = p->db;
      sqlite3ValueSetStr(db->pErr, -1, p->zErrMsg, SQLITE_UTF8, sqlite3FreeX);
      db->errCode = p->rc;
      p->zErrMsg = 0;
    }else if( p->rc ){
      sqlite3Error(p->db, p->rc, 0);
    }else{
      sqlite3Error(p->db, SQLITE_OK, 0);
    }
  }else if( p->rc && p->expired ){

#
#***********************************************************************
#
# This file contains tests to ensure that the library handles malloc() failures
# correctly. The emphasis of these tests are the _prepare(), _step() and
# _finalize() calls.
#
# $Id: malloc3.test,v 1.8 2006/01/20 16:32:04 danielk1977 Exp $

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

# Only run these tests if memory debugging is turned on.
if {[info command sqlite_malloc_stat]==""} {
   puts "Skipping malloc tests: not compiled with -DSQLITE_MEMDEBUG..."

  if {![info exists ::STMT32]} {
    set sql "SELECT name FROM sqlite_master"
    set ::STMT32 [sqlite3_prepare $::DB $sql -1 DUMMY]
    do_test $testid {
      sqlite3_step $::STMT32
    } {SQLITE_ROW}
  }
}
SQL BEGIN
TEST 33 { 
  do_test $testid {
    execsql {SELECT * FROM ghi}
  } {a b c 1 2 3}
}
SQL -norollback { 

  -- There is a unique index on ghi(g), so this statement may not cause
  -- an automatic ROLLBACK. Hence the "-norollback" switch.
  INSERT INTO ghi SELECT '2'||g, h, i FROM ghi;
}
TEST 34 {
  if {[info exists ::STMT32]} {
    do_test $testid {
      sqlite3_finalize $::STMT32
    } {SQLITE_OK}
    unset ::STMT32
  }
}
SQL COMMIT

#
# End of test program declaration
#--------------------------------------------------------------------------

proc run_test {arglist {pcstart 0} {iFailStart 1}} {
  if {[llength $arglist] %2} {

# if {$iFail > ($iFailStart+1)} return
  }
}

# Turn of the Tcl interface's prepared statement caching facility.
db cache size 0

run_test $::run_test_script
# run_test [lrange $::run_test_script 0 3] 0 63
sqlite_malloc_fail 0
db close

pp_check_for_leaks

finish_test

#
#***********************************************************************
#
# The focus of the tests in this file are IO errors that occur in a shared
# cache context. What happens to connection B if one connection A encounters
# an IO-error whilst reading or writing the file-system?
#
# $Id: shared_err.test,v 1.2 2006/01/20 16:32:05 danielk1977 Exp $

proc skip {args} {}


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

ifcapable !shared_cache||!subquery {
  finish_test
  return
}
set ::enable_shared_cache [sqlite3_enable_shared_cache 1]


do_ioerr_test shared_ioerr-1 -tclprep {
  sqlite3 db2 test.db
  execsql {
    PRAGMA read_uncommitted = 1;
    CREATE TABLE t1(a,b,c);
    BEGIN;
    SELECT * FROM sqlite_master;

  BEGIN TRANSACTION;
  INSERT INTO t1 VALUES(1,2,3);
  INSERT INTO t1 VALUES(4,5,6);
  COMMIT;
  SELECT * FROM t1;
  DELETE FROM t1 WHERE a<100;
} -cleanup {
  do_test shared_ioerr-1.$n.cleanup.1 {
    set res [catchsql {
      SELECT * FROM t1;
    } db2]
    set possible_results [list            \
      "1 {disk I/O error}"                \
      "0 {1 2 3}"                         \
      "0 {1 2 3 1 2 3 4 5 6}"             \

      puts ""
      puts "Result: \"$res\" ($::residx)"
    }
    set success
  } {1}
  db2 close
}

# This test is designed to provoke an IO error when a cursor position is
# "saved" (because another cursor is going to modify the underlying table). 
# 
do_ioerr_test shared_ioerr-3 -tclprep {
  sqlite3 db2 test.db
  execsql {
    PRAGMA read_uncommitted = 1;
    BEGIN;
    CREATE TABLE t1(a, b, UNIQUE(a, b));
  } db2
  for {set i 0} {$i < 5} {incr i} {
    set a [string repeat $i 10]
    set b [string repeat $i 2000]
    execsql {INSERT INTO t1 VALUES($a, $b)} db2
  }
  execsql {COMMIT} db2
  set ::DB2 [sqlite3_connection_pointer db2]
  set ::STMT [sqlite3_prepare $::DB2 "SELECT a FROM t1 ORDER BY a" -1 DUMMY]
  sqlite3_step $::STMT       ;# Cursor points at 0000000000
  sqlite3_step $::STMT       ;# Cursor points at 1111111111
} -tclbody {
  execsql {
    INSERT INTO t1 VALUES(6, NULL);
  }
} -cleanup {
  do_test shared_ioerr-3.$n.cleanup.1 {
    sqlite3_step $::STMT
  } {SQLITE_ROW}
  do_test shared_ioerr-3.$n.cleanup.2 {
    sqlite3_column_text $::STMT 0
  } {2222222222}
  do_test shared_ioerr-3.$n.cleanup.3 {
    sqlite3_finalize $::STMT
  } {SQLITE_OK}
# db2 eval {select * from sqlite_master}
  db2 close
}

catch {db close}
sqlite3_enable_shared_cache $::enable_shared_cache
finish_test