Index: src/pager.c
==================================================================
--- src/pager.c
+++ src/pager.c
@@ -16,11 +16,11 @@
 ** 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 1.45 2002/04/18 01:56:58 drh Exp $
+** @(#) $Id: pager.c,v 1.46 2002/05/30 12:27:03 drh Exp $
 */
 #include "sqliteInt.h"
 #include "pager.h"
 #include "os.h"
 #include <assert.h>
@@ -112,10 +112,11 @@
   int nRef;                   /* Number of in-memory pages with PgHdr.nRef>0 */
   int mxPage;                 /* Maximum number of pages to hold in cache */
   int nHit, nMiss, nOvfl;     /* Cache hits, missing, and LRU overflows */
   u8 journalOpen;             /* True if journal file descriptors is valid */
   u8 ckptOpen;                /* True if the checkpoint journal is open */
+  u8 ckptInUse;               /* True we are in a checkpoint */
   u8 noSync;                  /* Do not sync the journal if true */
   u8 state;                   /* SQLITE_UNLOCK, _READLOCK or _WRITELOCK */
   u8 errMask;                 /* One of several kinds of errors */
   u8 tempFile;                /* zFilename is a temporary file */
   u8 readOnly;                /* True for a read-only database */
@@ -241,10 +242,14 @@
 static int pager_unwritelock(Pager *pPager){
   int rc;
   PgHdr *pPg;
   if( pPager->state<SQLITE_WRITELOCK ) return SQLITE_OK;
   sqlitepager_ckpt_commit(pPager);
+  if( pPager->ckptOpen ){
+    sqliteOsClose(&pPager->cpfd);
+    pPager->ckptOpen = 0;
+  }
   sqliteOsClose(&pPager->jfd);
   pPager->journalOpen = 0;
   sqliteOsDelete(pPager->zJournal);
   rc = sqliteOsReadLock(&pPager->fd);
   assert( rc==SQLITE_OK );
@@ -389,11 +394,11 @@
   rc = sqliteOsTruncate(&pPager->fd, pPager->ckptSize*SQLITE_PAGE_SIZE);
   pPager->dbSize = pPager->ckptSize;
 
   /* Figure out how many records are in the checkpoint journal.
   */
-  assert( pPager->ckptOpen && pPager->journalOpen );
+  assert( pPager->ckptInUse && pPager->journalOpen );
   sqliteOsSeek(&pPager->cpfd, 0);
   rc = sqliteOsFileSize(&pPager->cpfd, &nRec);
   if( rc!=SQLITE_OK ){
     goto end_ckpt_playback;
   }
@@ -526,10 +531,11 @@
   strcpy(pPager->zJournal, zFilename);
   strcpy(&pPager->zJournal[nameLen], "-journal");
   pPager->fd = fd;
   pPager->journalOpen = 0;
   pPager->ckptOpen = 0;
+  pPager->ckptInUse = 0;
   pPager->nRef = 0;
   pPager->dbSize = -1;
   pPager->ckptSize = 0;
   pPager->ckptJSize = 0;
   pPager->nPage = 0;
@@ -612,13 +618,15 @@
     pNext = pPg->pNextAll;
     sqliteFree(pPg);
   }
   sqliteOsClose(&pPager->fd);
   assert( pPager->journalOpen==0 );
-  if( pPager->tempFile ){
-    /* sqliteOsDelete(pPager->zFilename); */
-  }
+  /* Temp files are automatically deleted by the OS
+  ** if( pPager->tempFile ){
+  **   sqliteOsDelete(pPager->zFilename);
+  ** }
+  */
   sqliteFree(pPager);
   return SQLITE_OK;
 }
 
 /*
@@ -1088,11 +1096,11 @@
 
   /* Mark the page as dirty.  If the page has already been written
   ** to the journal then we can return right away.
   */
   pPg->dirty = 1;
-  if( pPg->inJournal && (pPg->inCkpt || pPager->ckptOpen==0) ){
+  if( pPg->inJournal && (pPg->inCkpt || pPager->ckptInUse==0) ){
     pPager->dirtyFile = 1;
     return SQLITE_OK;
   }
 
   /* If we get this far, it means that the page needs to be
@@ -1125,20 +1133,20 @@
     }
     assert( pPager->aInJournal!=0 );
     pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
     pPager->needSync = !pPager->noSync;
     pPg->inJournal = 1;
-    if( pPager->ckptOpen ){
+    if( pPager->ckptInUse ){
       pPager->aInCkpt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
       pPg->inCkpt = 1;
     }
   }
 
   /* If the checkpoint journal is open and the page is not in it,
   ** then write the current page to the checkpoint journal.
   */
-  if( pPager->ckptOpen && !pPg->inCkpt && (int)pPg->pgno<=pPager->ckptSize ){
+  if( pPager->ckptInUse && !pPg->inCkpt && (int)pPg->pgno<=pPager->ckptSize ){
     assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
     rc = sqliteOsWrite(&pPager->cpfd, &pPg->pgno, sizeof(Pgno));
     if( rc==SQLITE_OK ){
       rc = sqliteOsWrite(&pPager->cpfd, pData, SQLITE_PAGE_SIZE);
     }
@@ -1204,16 +1212,16 @@
   if( pPager->state!=SQLITE_WRITELOCK || pPager->journalOpen==0 ) return;
   if( !pPg->inJournal && (int)pPg->pgno <= pPager->origDbSize ){
     assert( pPager->aInJournal!=0 );
     pPager->aInJournal[pPg->pgno/8] |= 1<<(pPg->pgno&7);
     pPg->inJournal = 1;
-    if( pPager->ckptOpen ){
+    if( pPager->ckptInUse ){
       pPager->aInCkpt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
       pPg->inCkpt = 1;
     }
   }
-  if( pPager->ckptOpen && !pPg->inCkpt && (int)pPg->pgno<=pPager->ckptSize ){
+  if( pPager->ckptInUse && !pPg->inCkpt && (int)pPg->pgno<=pPager->ckptSize ){
     assert( pPg->inJournal || (int)pPg->pgno>pPager->origDbSize );
     assert( pPager->aInCkpt!=0 );
     pPager->aInCkpt[pPg->pgno/8] |= 1<<(pPg->pgno&7);
     pPg->inCkpt = 1;
   }
@@ -1343,22 +1351,25 @@
 */
 int sqlitepager_ckpt_begin(Pager *pPager){
   int rc;
   char zTemp[SQLITE_TEMPNAME_SIZE];
   assert( pPager->journalOpen );
-  assert( !pPager->ckptOpen );
+  assert( !pPager->ckptInUse );
   pPager->aInCkpt = sqliteMalloc( pPager->dbSize/8 + 1 );
   if( pPager->aInCkpt==0 ){
     sqliteOsReadLock(&pPager->fd);
     return SQLITE_NOMEM;
   }
   rc = sqliteOsFileSize(&pPager->jfd, &pPager->ckptJSize);
   if( rc ) goto ckpt_begin_failed;
   pPager->ckptSize = pPager->dbSize;
-  rc = sqlitepager_opentemp(zTemp, &pPager->cpfd);
-  if( rc ) goto ckpt_begin_failed;
-  pPager->ckptOpen = 1;
+  if( !pPager->ckptOpen ){
+    rc = sqlitepager_opentemp(zTemp, &pPager->cpfd);
+    if( rc ) goto ckpt_begin_failed;
+    pPager->ckptOpen = 1;
+  }
+  pPager->ckptInUse = 1;
   return SQLITE_OK;
  
 ckpt_begin_failed:
   if( pPager->aInCkpt ){
     sqliteFree(pPager->aInCkpt);
@@ -1369,14 +1380,14 @@
 
 /*
 ** Commit a checkpoint.
 */
 int sqlitepager_ckpt_commit(Pager *pPager){
-  if( pPager->ckptOpen ){
+  if( pPager->ckptInUse ){
     PgHdr *pPg;
-    sqliteOsClose(&pPager->cpfd);
-    pPager->ckptOpen = 0;
+    sqliteOsTruncate(&pPager->cpfd, 0);
+    pPager->ckptInUse = 0;
     sqliteFree( pPager->aInCkpt );
     pPager->aInCkpt = 0;
     for(pPg=pPager->pAll; pPg; pPg=pPg->pNextAll){
       pPg->inCkpt = 0;
     }
@@ -1387,11 +1398,11 @@
 /*
 ** Rollback a checkpoint.
 */
 int sqlitepager_ckpt_rollback(Pager *pPager){
   int rc;
-  if( pPager->ckptOpen ){
+  if( pPager->ckptInUse ){
     rc = pager_ckpt_playback(pPager);
     sqlitepager_ckpt_commit(pPager);
   }else{
     rc = SQLITE_OK;
   }

Index: test/expr.test
==================================================================
--- test/expr.test
+++ test/expr.test
@@ -9,11 +9,11 @@
 #
 #***********************************************************************
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing expressions.
 #
-# $Id: expr.test,v 1.22 2002/05/30 02:35:12 drh Exp $
+# $Id: expr.test,v 1.23 2002/05/30 12:27:03 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 
 # Create a table to work with.
@@ -352,11 +352,13 @@
 	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 'error' END} error
 test_expr expr-case.10 {i1=3} \
 	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' END} {{}}
 test_expr expr-case.11 {i1=null} \
 	{CASE i1 WHEN 1 THEN 'one' WHEN 2 THEN 'two' ELSE 3 END} {{}}
-test_expr expr-case.12 {i1=7} \
+test_expr expr-case.12 {i1=1} \
+	{CASE i1 WHEN 1 THEN null WHEN 2 THEN 'two' ELSE 3 END} {{}}
+test_expr expr-case.13 {i1=7} \
 	{ CASE WHEN i1 < 5 THEN 'low' 
 	       WHEN i1 < 10 THEN 'medium' 
                WHEN i1 < 15 THEN 'high' ELSE 'error' END} medium