From 5e1fa03dcae6aad2bf633d5693a76d9dd3c1e310 Mon Sep 17 00:00:00 2001
From: drh <drh@noemail.net>
Date: Sat, 25 Jul 2009 15:24:13 +0000
Subject: [PATCH] Simplifications and comment improvements to pager.c in
 support of coverage testing. (CVS 6938)

FossilOrigin-Name: 5b70b5c19cd587a8afbf2909ac7a4c04aea20f44
---
 manifest      | 12 ++++++------
 manifest.uuid |  2 +-
 src/pager.c   | 21 +++++++++++----------
 3 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/manifest b/manifest
index 1f4d4aaa21..c41fa03d57 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sa\sNEVER()\son\san\salways-false\sconditional\sin\spager.c.\nMake\ssure\sthe\stext\sof\sthe\smaster\sjournal\sfile\sis\szero-terminated\sbefore\ntrying\sto\sprocess\sit\s-\sto\sprevent\sa\sbuffer\soverrun\sin\sstrlen().\s(CVS\s6937)
-D 2009-07-25T14:18:57
+C Simplifications\sand\scomment\simprovements\sto\spager.c\sin\ssupport\sof\scoverage\ntesting.\s(CVS\s6938)
+D 2009-07-25T15:24:14
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in df9359da7a726ccb67a45db905c5447d5c00c6ef
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -147,7 +147,7 @@ F src/os_common.h 8c61457df58f1a4bd5f5adc3e90e01b37bf7afbc
 F src/os_os2.c bed77dc26e3a95ce4a204936b9a1ca6fe612fcc5
 F src/os_unix.c cdb2a08b9ce4aa13b3f7b91d4dd60fb48be9f56a
 F src/os_win.c 725c38a524d168ce280446ad8761d731bc516405
-F src/pager.c 23c9823d72b0213d7cbf3ca6e5aeb9735b467d5d
+F src/pager.c 9ba1c7412f5f8fc1c98d0662a81f3842b0995300
 F src/pager.h 11852d044c86cf5a9d6e34171fb0c4fcf1f6265f
 F src/parse.y bcd46d43fbd23a22b8c020a3eb1806b794794ed5
 F src/pcache.c c92ffd4f3e1279b3766854c6d18b5bf4aac0d1fa
@@ -738,7 +738,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
-P 03153831635342a744ee42f14cb041499cdece2a
-R 4106cc756a07d0d168a7b40655b87b37
+P cc9430e334fe98e1c35d408f81a2d8953377cda6
+R e5fb6459ed2755d7a158ac65e619d65e
 U drh
-Z 8238038a139f353098e7137beba5542a
+Z ab499bece38a6094beca9b024b831cb1
diff --git a/manifest.uuid b/manifest.uuid
index e16fc81ced..7738bb4222 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-cc9430e334fe98e1c35d408f81a2d8953377cda6
\ No newline at end of file
+5b70b5c19cd587a8afbf2909ac7a4c04aea20f44
\ No newline at end of file
diff --git a/src/pager.c b/src/pager.c
index b5c7ca5f27..fd97acccff 100644
--- a/src/pager.c
+++ b/src/pager.c
@@ -18,7 +18,7 @@
 ** file simultaneously, or one process from reading the database while
 ** another is writing.
 **
-** @(#) $Id: pager.c,v 1.622 2009/07/25 14:18:57 drh Exp $
+** @(#) $Id: pager.c,v 1.623 2009/07/25 15:24:14 drh Exp $
 */
 #ifndef SQLITE_OMIT_DISKIO
 #include "sqliteInt.h"
@@ -1302,11 +1302,8 @@ static int pager_end_transaction(Pager *pPager, int hasMaster){
 
     /* Finalize the journal file. */
     if( pPager->journalMode==PAGER_JOURNALMODE_MEMORY ){
-      int isMemoryJournal = sqlite3IsMemJournal(pPager->jfd);
+      assert( sqlite3IsMemJournal(pPager->jfd) );
       sqlite3OsClose(pPager->jfd);
-      if( !isMemoryJournal ){
-        rc = sqlite3OsDelete(pPager->pVfs, pPager->zJournal, 0);
-      }
     }else if( pPager->journalMode==PAGER_JOURNALMODE_TRUNCATE ){
       if( pPager->journalOff==0 ){
         rc = SQLITE_OK;
@@ -4211,6 +4208,11 @@ static int pager_write(PgHdr *pPg){
   Pager *pPager = pPg->pPager;
   int rc = SQLITE_OK;
 
+  /* This routine is not called unless a transaction has already been
+  ** started.
+  */
+  assert( pPager->state>=PAGER_RESERVED );
+
   /* If an error has been previously detected, we should not be
   ** calling this routine.  Repeat the error for robustness.
   */
@@ -4236,15 +4238,14 @@ static int pager_write(PgHdr *pPg){
     ** written to the transaction journal or the ckeckpoint journal
     ** or both.
     **
-    ** First check to see that the transaction journal exists and
-    ** create it if it does not.
+    ** Higher level routines should have already started a transaction,
+    ** which means they have acquired the necessary locks and opened
+    ** a rollback journal.  Double-check to makes sure this is the case.
     */
-    assert( pPager->state!=PAGER_UNLOCK );
     rc = sqlite3PagerBegin(pPager, 0, pPager->subjInMemory);
-    if( rc!=SQLITE_OK ){
+    if( NEVER(rc!=SQLITE_OK) ){
       return rc;
     }
-    assert( pPager->state>=PAGER_RESERVED );
     if( !isOpen(pPager->jfd) && pPager->journalMode!=PAGER_JOURNALMODE_OFF ){
       assert( pPager->useJournal );
       rc = pager_open_journal(pPager);